2013 PRESENTATION ABSTRACTS
Diet pattern and longevity: Do simple rules suffice?
David R. Jacobs, PhD | Plenary Address Sunday, February 24, 2013
Among the most consistent findings in nutritional epidemiology is that certain diet patterns are associated with lower chronic disease risk over very long follow-up periods. The favorable patterns are typically called “Prudent”, while the corresponding unfavorable patterns are “Western”. The Prudent patterns are notably plant-centered and focus on favorable preparation methods and minimal preprocessing by industry. The Western patterns favor high intake of meat, plant foods in which phytochemicals have been stripped, and preparation/processing to satisfy sweet or salt tastes and for long shelf life. Furthermore, such patterns appear to be remarkably stable across adult life. These findings have profound implications for advice to the public and for the future of nutrition research. People eat food (not nutrients) in patterns. Each food is a nonrandom mixture of constituents, operating in concert for the life of the organism eaten and presumably for the life of the eater. Any nutrition advice should be based on and respect this remarkable complexity of food and the patterns in which it is eaten. Nutrition research has been hampered by focus on individual nutrients; the advice to the public based on nutrients has been inconsistent and unreliable, often fostering the supplement industry, rather than the food industry. A useful direction for nutrition research would be to start with known complex dietary patterns and food as the unit of study, then examine what happens to various outcome variables as these complex patterns are tweaked to make them even better. There are many highly satisfactory dietary patterns. Simple rules are sufficient to describe them, with much left to individual choice. We may double Michael Pollan’s 7 word dictum to 14 words: Eat food. Mostly plants. Not too much. In colorful variety. Maximize nutrients per bite.
Walnuts and berries for the brain
Barbara Shukitt-Hale, PhD | Symposium: Plan based diet patterns and healthy aging
Average lifespans have increased dramatically over the last century and by the year 2050 fully 30% of the total population will be over 65 years of age. There is a high probability that these people will be exhibiting the most common behavioral changes that occur in “normal” aging - impaired mobility and cognitive performance. These deficits may be due oxidative damage caused by free-radicals and inflammatory response to this and other cellular damage. Therefore, foods high in antioxidant and anti-inflammatory activity, such as berries and nuts could prevent and even reverse the occurrence of the neurochemical and behavioral changes that occur in aging. Previously, we have shown that whole, crude berry extracts and walnuts are able to reverse several parameters of brain aging as well as age-related motor and cognitive deficits when fed to rats from 19-21 months of age. These effects may be the result of direct effects on brain signaling or indirect effects through antioxidant and anti-inflammatory properties of the polyphenols in these foods. If these effects translate to older adults, dietary interventions, such as the inclusion of additional servings of berry fruits or nuts, present a potential means of delaying or minimizing the negative effects of aging on the brain.
Dietary n-3 fatty acids and Alzheimer disease: Does the source matter?
Gregory Cole, PhD | Symposium: Plant based diet patterns and healthy aging
Risk for dementia, most notably Alzheimer Disease (AD), rises with age, doubling every 5 years after age 65 to eventually impact 30 to 50 percent of those over 90 years of age. With an aging population and no cure in sight, researchers have discovered effective biomarkers to diagnose AD pathogenesis during the decades long prodromal period of accumulating beta amyloid in plaques, phosphor-tau in tangles and neurodegenerative pathology. Candidate treatment approaches have repeatedly failed and if successful are likely to be very expensive. No successful prevention method has been demonstrated. Therefore, our research has focused on low cost prevention approaches including non-steroidal anti-inflammatory drugs, antioxidants and other natural polyphenols. Epidemiology shows reduced AD risk in persons with higher fatty fish intake or higher blood levels of the omega-3 fatty acid, DHA. DHA is enriched in neurons and with six double bonds, susceptible to lipid peroxidation, a process known to be accelerated in AD brain despite evidence for reduced DHA levels. We found that a DHA-depleting diet increased excitatory synaptic marker loss in beta amyloid accumulating AD model mice. In contrast, supplementing with DHA protected synaptic markers and behavior and reduced amyloid peptide accumulation. Further studies by our group and others show that DHA protects from other AD pathogenic processes including Abeta peptide toxicity, phospho-tau accumulation and neuronal insulin signaling defects. Clinical trial evidence reports DHA containing products are protective for mild cognitive impairments but not effective in mild to moderate AD. Data from some but not all epidemiology, a clinical trial and an animal model suggests some n-3 protective effects depend on subject genotype for common alleles of the major AD genetic risk gene, Apolipoprotein E. DHA can be from fish, fish oil or marine algae or synthesized from plant sourced linolenic acid.
Plant based diets, n-3 fatty acids and risk of osteoporosis
Katherine Tucker, PhD | Symposium: Plant based diet patterns and healthy aging
In contrast to an earlier almost exclusive focus on calcium and vitamin D for protecting bone, recent investigation of diet and osteoporosis has identified many components that affect bone mineral density and risk of fracture. This includes the importance of fruit and vegetables and their antioxidant and anti-inflammatory vitamins and other phytonutrients, as well as reinforcement of the need for other minerals, particularly magnesium and potassium. An interesting area of ongoing research is that of protein. Formerly thought to have a negative effect on calcium balance, many studies have now shown that higher protein in the diet is protective of bone mineral density and against fracture. Whether plant or animal source protein is important remains an important question. Fatty acids are also important, although the evidence suggests that their relationship to bone is even more complex. It is increasingly clear that total dietary patterns that are healthy and balanced and heavily plant based are beneficial to bone as well as to heart disease and other chronic conditions. In addition to calcium, vitamin D, protein and n-3 fatty acids, particular nutrients to be aware of when following totally plant based diets include vitamin B12.
Plant-based macular xanthophylls, n-3 fatty acids and age-related macular degeneration
John Paul SanGiovanni, ScD, MS, MA | Symposium: Plant based diet patterns and healthy aging
Advanced age-related macular degenration (AAMD) is the leading cause of blindness in elderly people of western European ancestry. More than 2 million U.S. residents have AAMD. Current treatments (intraocular injections with anti-angiogenic drugs) are a substantial financial burden on society, with direct annual medical costs reaching ~570 million dollars. AMD-related outpatient services are accessed annually by ~1.4 million people in the U.S.. Less expensive and non-invasive treatment options for AAMD are needed. Nutrient-based approaches to AMD prevention and treatment have focused on compounds demonstrating: 1) intake-dependent and –modifiable accretion to retinal cell types affected in AMD; and 2) biochemical capacity to act on processes implicated in AMD pathogenesis. Large-scale human studies on AMD suggest a reduced likelihood of having neovascular AMD among people reporting highest dietary intakes of lutein/zeaxanthin (L/Z) and omega-3 (ω-3) long-chain polyunsaturated fatty acids (LCPUFAs). L/Z and ω-3 LCPUFAs have the capacity to act as key structural and signaling molecules in the retina. Here, we review the state of science supporting the putative roles of these nutirents, their biosynthetic and cleavage enzymes, transporters, receptors, and transcriptional regulators in prevention and treatment of AAMD. We will discuss novel findings on AMD-associated DNA sequence variants in genes encoding proteins influencing or influenced by L/Z.
Update on Adventist Health Study-2
Gary Fraser, MB ChB, PhD | Symposium: Epidemiological studies of vegetarians
The Adventist Health Study-2 cohort consists of 96,000 subjects from U.S. and Canada. Comprehensive dietary information was gathered at study baseline (2002-2007), and then subjects were followed for mortality and cancer incidence. Sub-studies gathered blood and other bio-specimens from 2,700 subjects. Many biomarkers of dietary intake have been analyzed in 900 representative subjects. At present we have more than 5000 fatal end-points and about 2,700 incident cancer endpoints (we expect this to be 5,000 in about one year after completing matching with state cancer registries). Results to date show that vegetarians, especially vegans have much lower BMI than non-vegetarians, and this is so also for Black subjects. In addition blood pressures and serum cholesterols are lower in vegetarians, as are prevalences of hypertension and hyperlipidemia. Prevalence and incidence of diabetes is lower, as are levels of fasting glucose. Risk factors for cancer, including blood insulin, and CRP are lower in vegetarians, but IGF-1 and IGFBP-3 are low in vegans and non-vegetarians but higher in lacto-ovo vegetarians. Measures of immune function such as IL-6, IL-10 and TNF-alpha did not vary significantly by dietary pattern. Preliminary total cancer incidence data indicates lower risk among vegans when compared to non-vegetarians, but no clear difference yet between vegans and lacto-ovo vegetarians. When compared to non-vegetarians, vegans have lower risk of female cancers, and lacto-ovo vegetarians have lower risk of gastro-intestinal cancers. Regarding total mortality the main observation is that all vegetarian categories combined have significantly lower mortality than non-vegetarians, and that this is statistically significant also for pesco-vegetarians, and very nearly so for lacto-ovo vegetarians and vegans. Cardiovascular, endocrine (mainly diabetes), and renal deaths were significantly lower among vegetarians. In summary it is clear that a plant-based vegetarian diet has many health advantages, although we cannot yet discriminate between different types of vegetarian diets.
Update from the EPIC-Oxford Study
Timothy Key, PhD | Symposium: Epidemiological studies of vegetarians
EPIC-Oxford is a prospective study of 65,500 men and women living in the United Kingdom, who were recruited between 1993 and 1999. The population comprises approximately 34,000 meat-eaters, 10,000 “fish-eaters” (people who do not eat meat but do eat fish), 19,000 vegetarians and 2,500 vegans. The nutritional status and health of these people has been studied by examining dietary intake, anthropometry and blood levels of nutrients at the time of recruitment, and by following individuals with repeat questionnaires and data linkage with cancer registries, mortality indexes and, more recently, records of hospital diagnoses. These findings will be discussed, including examination of vitamin B12 and vitamin D status, incidence of ischemic heart disease, diverticular disease and cataracts, and incidence of the major cancer sites.
Cognition: The new frontier for nuts
Peter Pribis, MD, DrPH | Symposium: Role of nuts in disease prevention
In the last twenty years nutritional neuroscience has developed into a recognized discipline with the potential to make significant contributions to our understanding of the relationship between nutrition and cognition. Research conducted on animals and humans indicates that different neural systems could be affected by dietary manipulations including fruits, vegetables, fish and nuts. Nuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative phytochemicals (flavonoids, anthocyanidins, phenolic acids) and Alpha-linolenic acid (C18:3n-3) which is the precursor for the long-chain omega-3 fatty acids (EPA and DHA) which could be incorporated into the brain cell membranes and subsequently influence cognitive processing. Tree nuts may prove to be important nutritional interventions in the prevention and treatment of cognitive decline and mood disorders. Further research is needed to study the long- and short-term effects of nut consumption on cognitive processes.
Nuts in the prevention and treatment of cardio-metabolic syndrome
Jordi Salas-Salvado, MD, PhD | Symposium: Role of nuts in disease prevention
The prevalence of metabolic syndrome (MetS) has increased worldwide in the last decades, becoming a major public health problem. Nuts have a healthy nutritional profile that is known to exert beneficial effects on cardiovascular health. We review the evidence relating nut consumption and MetS and its components. Few epidemiological studies have assessed the association between nuts and abdominal obesity, although an increase association with BMI or risk of general obesity has been reported; also available data indicates that consuming nuts in moderate amounts does not lead to any appreciable weight gain. Nut consumption was associated with lower risk of diabetes incidence only in women. Acute feeding trials support that nuts reduce the postprandial glycemic response; however, the evidence from long-term clinical trials evaluating the impacts of nuts on insulin resistance and glycemic control in diabetic individuals is controversial. Limited evidence from epidemiologic studies and trials suggest a protective effect of nuts on blood pressure. Even though it is recognized that nuts have a cholesterol-lowering effect, the relationship between nuts and hypertriglyceridemia and HDL-cholesterol is not well established. However, a recent pooled meta-analysis of clinical trials showed that nuts are inversely related to triglycerides concentrations only in subjects with hypertriglyceridemia. In relation to the MetS, an inverse association between the frequency of nuts consumption and the prevalence and the incidence of MetS was shown. Several clinical trials have evaluated the effects of nuts on subjects with MetS, suggesting beneficial effects in some MetS components. Compared to a low-fat diet, a Mediterranean diet enriched with nuts has been demonstrated to be beneficial in the MetS management. The protective effects on metabolism could be explained by several mechanisms through the modulation of the inflammatory processes and oxidation. Further trials are needed to clarify the role of nuts on MetS prevention and treatment.
Nut consumption, body weight and obesity
Frank Hu, MD, MPH, PhD | Symposium: Role of nuts in disease prevention
Abstract not available at time of print.
Nut consumption: Acceptability, satiety and metabolism
Richard Mattes, MPH, PhD, RD | Symposium: Role of nuts in disease prevention
Nuts are good sources of many nutrients including protein, fiber, vitamins (e.g. vitamin E), minerals (e.g. magnesium, zinc) as well as selected polyphenolic antioxidants (e.g. resveratrol). Additionally, their fat is primarily unsaturated. Epidemiological data and clinical trials indicate nut consumption is associated with reduced chronic disease risk through moderation of lipid profiles, glycemia and blood pressure. Consequently, there have been increasing recommendations to include nuts in the diet. One barrier to adoption of this advice has been concern about their high energy density and potential to promote weight gain. However, epidemiological data consistently reveal either no association or an inverse relationship between nut consumption and body mass index. Short term clinical trials confirm the inclusion of nuts in the diet does not promote weight gain, nor does it impede weight loss. Three primary mechanisms account for these observations. The largest is the high satiety value of nuts. They elicit strong dietary compensation that offsets approximately 2/3-3/4 of the energy they yield. Second, due to poor bioaccessability, there is limited efficiency of absorption of the energy they contain. Estimates of energy losses range from 5-20% of their content. Third, though the evidence is weaker, there are findings that chronic nut consumption is associated with an increase of resting metabolic rate. This results in the loss of another 5-10% of the energy obtained from nuts. Combined, these three responses account for nearly all of the energy contained in a moderate portion. Recognizing snacking may pose a threat for weight gain, recent studies have explored responses to nuts as snacks versus meal accompaniments. Early findings suggest there is strong compensation for nuts even when ingested between meals. Another potential barrier increased chronic nut consumption is sensory monotony. Studies of this issue reveal stable acceptance ratings over time independent of flavor additions.
Obesity Trends in a Vegetarian Subcontinent: India
Pramil Singh, DrPH | Symposium: Vegetarian diet patterns and obesity
The substantial increase in the prevalence of diabetes, CHD, and stroke in India points to the occurrence of an epidemiologic transition due to a higher prevalence of traditional cardiovascular disease risk factors such as diet (higher saturated fat and meat intake), physical inactivity, and tobacco use. Our group at Loma Linda University found that faith-based vegetarians who changed their diet pattern from zero meat intake to weekly meat intake during a 17-year period, then experienced weight gain, obesity, an increased risk of non-communicable disease (diabetes, stroke, and CHD), and a 3.6 year decrease in life expectancy. Evidence for this process occurring in rural and urban India is emerging. The prevalence of overweight/obesity in many rural areas exceeds 20%. Moreover, NCD biomarker data from Asian Indians have long raised the possibility of an "Asian Indian Phenotype" which produces a high-risk metabolic profile (i.e. insulin resistance, metabolic syndrome, elevated homocysteine and inflammatory cytokines) that makes Asian Indians especially sensitive to excess body fat. The WHO proposed a more sensitive indicator (body mass index >=23) of overweight/obesity for Asian populations and, using this cutpoint, large-scale prevalence surveys in South India indicate that more than 30% of rural adults are overweight/obese. Implications of the changing trends in meat intake and obesity in India are discussed, and data from Asian cohort members of Adventist Health Study-2 is presented.
Vegetarian diets for weight loss: Evidence from clinical trials
Neal Barnard, MD | Symposium: Vegetarian diet patterns and obesity
In observational studies, people following vegetarian diets typically have lower body weights, compared with individuals following omnivorous diets. To estimate the effect of vegetarian (including vegan) diets on the body weight of omnivores who adopt them, we reviewed findings from clinical intervention trials that quantified the relationships between plant-based diets instituted without restrictions on energy intake and body weight. We identified 14 intervention trials including 608 participants who adopted vegetarian diets (170 ovo-lacto-vegetarian and 438 vegan), with study durations ranging from 4 weeks to over 2 years. In 13 of these studies, participants lost weight, with mean weight change ranging from -1.8 kg to -7.8 kg, with considerable variation between individuals. One study, conducted in young, physically active, normal-weight individuals, reported a weight gain of 0.5 kg over 9 weeks. Higher baseline body weight was associated with greater weight loss during trials, and vegan diets generally let to greater weight loss, compared with ovo-lacto-vegetarian diets. Two mechanisms appear to account for the weight-reducing effect of plant-based diets. The high-fiber content of plant-based meals, often accompanied by a low fat content, reduced energy density of the diet, which in turn, reduced energy intake. In addition, plant-based diets may increase the postprandial metabolic rate. Specifically, a low-fat vegan diet has been shown to improve insulin sensitivity which, in turn, increases the thermic effect of food, apparently by increasing the passage of glucose into cells. We conclude that consistent evidence from clinical trials shows that vegetarian (including vegan) diets reduce body weight.
Population-based studies have shown that body mass index is lower for vegetarians than non-vegetarians, and that caloric intake for vegetarian diet patterns can be as much as 460 kcal less than those of non-vegetarians. This suggests the usefulness of vegetarian diet patterns as an approach for weight management. However, the perception exists that vegetarian diets are deficient in important nutrients, including protein, calcium, iron and vitamin B12. Data from recent NHANES analyses, as well as previous population studies, characterizing a lacto-ovo vegetarian diet pattern do not entirely support these concerns. A comparison of one-day nutrient intakes adjusted for calories showed that a lacto-ovo vegetarian diet was more nutrient dense than a non-vegetarian diet. However, a comparison of subgroups defined as dieters showed that diet quality was better for the non-vegetarians. In a subsequent analysis, the National Cancer Institute method was used to determine usual intake of nutrients for the lacto-ovo vegetarian diet pattern compared to a non-vegetarian diet, and dietary adequacy was assessed by comparing nutrient intakes to Estimated Average Requirements. High risk for inadequate nutrient intake was defined as one-third to more than one-half of the population having inadequate intakes. Following this approach, the risk for inadequate intake of vitamin B12 and iron were not considered high for either group, although the risk was greater for vegetarians. Both groups had high risk for inadequate intake of calcium and vitamin D. While quality and adequacy of a lacto-ovo vegetarian diet may be similar to or better than that of non-vegetarians, there may be a critical point at which decreasing energy intake would result in nutrient intakes below recommendations. Vegetarians typically consume fewer calories than non-vegetarians, so nutrition professionals should recommend vegetarian diets for weight management without further reductions in energy intake.
Thyroid disease according to type of vegetarian diet
Serena Tonstad, MD, PhD, MPH | Symposium: Vegetarian diet patterns and obesity
BACKGROUND & METHODS: Diets eliminating animal products may protect against autoimmune disease. We studied a range of vegetarian diets in relation to risk of hypo- and hyperthyroidism in the Adventist Health Study-2. Participants provided demographic and medical history data in a self-administered questionnaire. Thyroid disease was queried at baseline in 2002 and at follow-up to 2008. Determinants of prevalent (n=4,237 of 65,981 [6.4%]) and incident cases (1,184 of 41,212 [2.9%]) of hypothyroidism and prevalent cases of hyperthyroidism (603 of 65,981 [0.9%]) were examined in multivariate logistic regression models controlled for demographics and salt use. RESULTS: As expected, male gender protected against prevalent hypo- and hyperthyroidism while Blacks (OR 0.21, 95% CI, 0.19-0.24) were protected against prevalent hypothyroidism. Overweight and obesity were associated with increased odds of hypothyroidism (OR 1.32, 95% CI 1.22-1.42 and 1.78, 95% CI 1.64-1.93, respectively) and obesity with higher odds of hyperthyroidism (OR 1.29, 95% CI 1.05-1.58). Vegan versus omnivorous diets tended to reduce risk of hypothyroidism (OR 0.89, 95% CI 0.78-1.01) while a lacto-ovo diet was associated with increased risk (OR 1.06, 95% CI 1.01-1.18). Incident hypothyroidism was associated with female gender, White ethnicity, higher education and BMI; additionally, following a vegan diet was protective (OR 0.74, 95% CI 0.58-0.95). Vegan, lacto-ovo and pesco-vegetarian diets were associated with lower odds of hyperthyroidism (OR 0.38, 95% CI 0.32-0.71; OR 0.64, 95% CI 0.52-0.79; OR 0.73, 95% CI 0.55-0.98). CONCLUSION: Exclusion of animal foods was associated with lower risk of thyroid disease after control of confounders, though under-diagnosis in dietary groups cannot be excluded.
Vegetarian diets: Past, present and the future
Claus Leitzmann, PhD | Plenary Address February 25, 2013
The history of vegetarian nutrition began in the 6th century B.C. with the famous Greek philosopher and mathematician Pythagoras. Considered the father of ethical vegetarianism, he influenced many of his peers like Plato and Plutarch. With the fall of ancient Greece, vegetarian nutrition almost disappeared in Europe until the renaissance era, when the genius Leonardo da Vinci revitalized the idea of vegetarian nutrition. During the age of enlightenment personalities like Rousseau, Voltaire and Wesley practiced vegetarian nutrition. The first vegetarian society was initiated in England in 1847, followed by other countries. The International Vegetarian Union was founded in 1908, the first Vegan Society started in 1944 and the European Vegetarian Union was formed in 1985. Prominent representatives of vegetarian nutrition during this period included EG White, Sylvester Graham, John Harvey Kellogg, and Maximilian Bircher-Benner. Today, vegetarian nutrition has a growing international following and it represents an increasingly popular diet. The main reasons for this modern movement are medical, environmental, and social concerns, in addition to religious and moral inspirations. Presently the dominant driving forces behind vegetarian nutrition are ethical and ecological considerations. The confirmed advantages of vegetarian nutrition are documented in many recent publications including large population based studies, such as the British EPIC study and the AHS I and II in North America. The current popularity of vegetarian nutrition is supported by an increasing number of vegetarians in the arts and sciences, in culture, and in sports. The growing interest and the standing of vegetarian nutrition in society are also documented in the great interest in national, regional and the World Vegetarian Nutrition Conferences. Vegetarian nutrition is flourishing.
The future of vegetarian nutrition is most promising. The prediction of an entirely vegetarian world within this century, however, may remain a dream. But, it could be one of the critical necessities for mankind to survive.
Meat, dairy, and cancer
Rashmi Sinha, PhD | Symposium: Vegetarian diet and prevention of cancer
The World Cancer Research Fund and American Institute for Cancer Research (WCRF/AICR) report in 2007 judged that red and processed meat consumption were “convincing” linked to colorectal cancer, and that milk consumption was “probably” protective against colorectal cancer. Since the publication of that report, the relationship between meat, dairy and cancer remains a matter of scientific debate in the literature. The focus has shifted toward studying compounds in meat—including heterocyclic amines, polycyclic aromatic hydrocarbons, N-nitroso compounds, and heme iron. The role of genetic polymorphisms in the relationship between meat-related compounds intake and cancer has also generated interest among researchers. Despite these new approaches, however, the findings remain somewhat inconsistent. While the evidence in favor of link between red and processed meat and colorectal cancer remain convincing, the relationships with other cancers are unclear. The WCRF/AICR concluded that milk was “probably” associated with inverse relationship with colorectal cancer, while there was “limited” evidence to suggest that milk had a similar relationship with bladder cancer. Diets high in calcium, however, were reported to “probably” increase the risk of prostate cancer, while milk and dairy products showed “limited” evidence of increasing the risk of prostate cancer. Likewise, the panel concluded that there was “limited” evidence in support of an inverse relationship between cheese intake and colorectal cancer.
Plant based dietary patterns, plants foods and cancer risk: findings from EPIC
Timothy Key, PhD | Symposium: Vegetarian diet and prevention of cancer
Ecological studies have shown that, for several of the major cancer sites, the incidence is higher in rich countries with high intakes of meat and dairy products than in poor countries with proportionately higher intakes of plant foods. This is the basis of several hypotheses concerning diet and cancer risk, but it has been unclear whether the associations might be due to adverse effects of meats and dairy products or to protective effects of plant foods. This topic will be examined in the light of results from EPIC - the European Prospective Investigation into Cancer and Nutrition. EPIC includes over 500,000 men and women in 10 European countries, spanning a substantial range of dietary patterns. The cohort has been followed since the early 1990s and there are now over 50,000 incident cancers. The results will be discussed with a focus on the relationships of fruits, vegetables and dietary fibre with the risk for the major cancer sites.
Nutrigenomics, plant based dietary patterns and cancer
Sharon Ross, PhD, MPH | Symposium: Vegetarian diet and prevention of cancer
Both epidemiological and preclinical evidence suggest that consumption of dietary phytochemicals (e.g., genistein and other isoflavones from soy products, epigallocatechin-3-gallate and other polyphenols in tea, isothiocyanates and indole-3-carbinol from cruciferous vegetables) are likely to alter susceptibility to cancer. Studies also suggest that a plant-based dietary pattern (including plant-based dietary patterns which also allow small intakes of red meat, fish and dairy products) may offer protection from cancer. In fact, one of the recommendations of the World Cancer Research Fund and the American Institute of Cancer Research (WCRF/AICR) in their report entitled, “Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective” is to “Eat more of a variety of vegetables, fruits, whole grains and legumes such as beans. Basing our diets on plant foods (like vegetables, fruits, whole grains and legumes such as beans), which contain fiber and other nutrients, can reduce our risk of cancer” (http://www.aicr.org/research/research_science_home.html). Not all studies, however, suggest a beneficial effect from consumption of phytochemicals or a plant based diet. Several factors may contribute to these incongruent findings, including host genetic variation in enzyme activity or pathways that affect absorption, metabolism, and distribution of phytochemicals. How such variation in response influences exposure at the tissue level and modifying disease risk in individuals is an area of active study. Nutrigenomics or nutritional genomics encompasses an understanding about how the response to bioactive food components depend on an individual’s genetic background or nutrigenetics, nutrient induced changes in DNA methylation and chromatin alterations or nutritional epigenetics, and nutrient induced changes in gene expression or nutritional transcriptomics. An overview of nutritional genomics, as well as examples and future directions will be presented in the context of phytochemicals, plant based dietary patterns and cancer prevention research.
Soy and women’s health
Mark Messina, PhD, MS | Symposium: Role of soy in health and disease
Soyfoods have received considerable attention for their role in women’s health and especially for helping women address conditions associated with the menopause transition. Interest in soyfoods is primarily because they are uniquely rich in dietary sources of isoflavones. Isoflavones are classified as both phytoestrogens and selective estrogen receptor modulators. Since 1995, at least 50 clinical studies have evaluated the ability of isoflavones from a variety of sources to alleviate menopause-related hot flashes. A recent meta-analysis that included 17 placebo-controlled studies found soy isoflavone supplements significantly alleviated both hot flash frequency and (n=13, p=0.00001) and severity (n=9, p=0.001) by approximately 50-60%. Isoflavones have also been shown to improve endothelial function in postmenopausal women with impaired endothelium and limited research indicates isoflavone intake is associated with higher circulating levels of endothelial progenitor cells. In contrast, although there are epidemiologic data from both Asia and the United States showing intake is protective against fracture, the results from clinical studies are very inconsistent. Most importantly, the three largest multi-year trials failed to find that isoflavone supplements affect postmenopausal bone mineral density. The longest (3 y) and largest trial also failed to find that isoflavone-rich soy protein affects global cognitive function although it may improve visual memory. Finally, the soy and breast cancer relationship has been the subject of rigorous investigation and considerable controversy. Intriguing evidence suggests that soy reduces breast cancer risk, but to derive this benefit requires consumption during childhood and/or adolescent. Interestingly, although animal data raised concerns that soy consumption could be harmful to breast cancer patients, a pooled analysis that included 9,514 survivors found that post-diagnosis soy intake was associated with a statistically significant 25% reduction in recurrence. Overall, the epidemiologic data, and especially the clinical data are supportive of soy consumption providing several benefits to postmenopausal women.
Soy and CHD: “The timing hypothesis”
Howard Hodis, MD | Symposium: Role of soy in health and disease
Although observational and case-control studies have consistently shown that hormone therapy (HT) reduces coronary heart disease (CHD) and total mortality, randomized controlled trials have failed to support these benefits when analyzed across all women regardless of age and/or time-since-menopause. However, it is now understood that the characteristics of women who participated in observational studies are markedly different from those of women enrolled in randomized controlled trials. Data strongly support that the discordance between observational studies and randomized controlled trials is related to timing of initiation of HT relative to age and/or proximity of menopause. Studies are in agreement when CHD and total mortality are analyzed according to timing of HT initiation; specifically, reduction in CHD and total mortality when HT is initiated in women <60 years old and/or <10 years-since-menopause. Selective estrogen receptor modulator (SERM) therapy has also been shown to reduce CHD in women who initiate therapy when <60 years old broadening the “timing hypothesis” across another class of medications. More recently, high-dose isoflavone soy protein supplementation has been shown to reduce the progression of atherosclerosis in women who were randomized within 5 years of menopause whereas women randomized more than 5 years beyond menopause showed no reduction of atherosclerosis progression with isoflavone soy protein supplementation. The totality of data support the hypothesis that reduction of CHD and total mortality is dependent upon the binding of compounds to the estrogen receptor when women are perimenopausal or recently postmenopausal.
Soy and prostate cancer
Raymond Bergan, MD | Symposium: Role of soy in health and disease
Natural products contain highly informative bioactive compounds. Their properties can facilitate the identification of heretofore unknown regulatory pathways of high biological as well as therapeutic relevance. Natural products can then be used to target those pathways. Starting from the anti-motility properties of the soy constituent, genistein, we have gone on to elucidate novel and key pathways responsible for regulating transformation of human prostate cancer to an aggressive and metastatic phenotype. We then used genistein to target those pathwaysm and have done so in pre-clinical models as well as in prospective human clinical trials. From this platform, we used genistein as chemical scaffold to support the synthesis and discovery of a more potent and specific new drug that inhibits human prostate cancer metastasis.
German vegans and vegetarians
Markus Keller, PhD | Mini-Symposium: Vegetarian studies: A global perspective
Since the late 1970s several studies have been carried out in Germany, with a total of about 2000 lacto- and lacto-ovo vegetarians (LOV) and 400 vegans (VG). The only prospective cohort study (1225 LOV, 60 VG) was carried out by the German Cancer Research Center, starting in 1978, with follow-ups in 1989 (11 years) and 1999 (21 years). The study examined the associations between a health conscious lifestyle, a vegetarian diet and mortality. The cross-sectional studies comprised smaller sample sizes (27-142 LOV, 24-154 VG). These studies predominantly evaluated the food habits, health behavior, nutrient intake, nutrient status and the health status. The main outcomes of the studies as compared with the general German population are as follows: 1. LOV have a reduced mortality. 2. LOV and VG have high intakes and show preventive blood levels of protective nutrients, especially of antioxidants; they have low intakes of risk factors (e.g. total fat, saturated fatty acids, cholesterol, and alcohol). 3. LOV show favorable levels of blood lipids, suggesting a lower CVD risk, a low BMI, low blood pressure and a very low prevalence of type 2 diabetes. 4. VG have favorable blood levels of total and LDL cholesterol, but unfavorable HDL cholesterol, homocysteine, and lipoprotein(a) blood levels, signifying a risk for CHD. 5. VG and many LOV show an impaired vitamin B12 status and a marginal vitamin B6 status. Vegan women of reproductive age show a high prevalence of iron deficiency.
Most of the data is rather old. New testing methods and recently established biomarkers will give more accurate results. Also the new generation of LOV and especially VG follow lifestyles that differ in many aspects, especially in health behavior and eating patterns from that of the older generation. Hence, there is an urgent need for new studies with German vegans and vegetarians.
Peter Clarys, PhD | Mini-Symposium: Vegetarian studies: A global perspective
The most recent national nutrition survey (2004) indicates that the number of vegetarians in Belgium and Flanders is low (1.2%) with the highest prevalence amongst the youngest age group tested (up to 3% amongst the 15 to 18 years old). Earlier studies on different groups of vegetarians indicate that a vegetarian diet as consumed in Flanders can be complete and adequate for all age groups (from 1 to 90 years old). The health aspects of vegetarian diets are well documented in the literature and also applicable on Flemish vegetarians. Notwithstanding the scientific evidence and the ecological advantages of switching from meat to vegetable proteins the number of people switching to a more plant based diet is limited. Knowledge of the determinants in the decision process to opt for a vegetarian diet or a vegetarian meal is required to improve the effectiveness of interventions towards more plant based diets. In the present contribution results of a recent online survey amongst Flemish vegans, lacto-ovo-vegetarians, pesco-vegetarians, semi- vegetarians and non–vegetarian (total n=1632) will be presented including nutritional analysis and healthy eating index analysis. Furthermore, the results of an online survey conducted by a professional market research agency probing towards eating habits; towards attitudes and beliefs concerning meat and vegetarian meal consumption; and towards the acceptance of campaigns such as Thursday Veggie day in male and female vegetarians; semi-vegetarians; and omnivores. (total n=2440) will be presented. Finally, a survey amongst vegetarian; occasionally vegetarian; and omnivorous university students (total n=200) concerning the motives and attitudes towards vegetarian diets and vegetarian meals will be presented. This ongoing research does not only allow us to follow trends concerning vegetarian nutrition in Flanders but equally to detect barriers for switching towards more plant based diets.
Cardiometabolic risk factors for Taiwanese omnivores and vegetarians
Tina Chiu, MPH, RD | Mini-Symposium: Vegetarian studies: A global perspective
While ample evidence on health effect of vegetarian diet exist for American and European populations. Very little is known about the Asian population, where vegetarians consume a very different diet and may have different diseases patterns. The Tzu Chi Health Study is a new cohort in Taiwan (n=6002), consisted mainly of devoted volunteers at the Buddhist Tzu Chi Foundation, who are required to abstain from tobacco and alcohol. One-third of participants were vegetarians. All participants received a comprehensive health examination and completed a diet-lifestyle and medical history questionnaire at baseline. Vegetarians had better profiles for many cardiometabolic risk factors but had higher homocysteine (Hcy) and lower serum vitamin B12. Vegetarians had a non-significant lower arterial stiffness as indicated by brachial-ankle Pulse-Wave Velocity (baPWV) compared with omnivores. Additional analysis showed that homocysteine is a main determinant of baPWV in vegetarians older than 55 years of age, but not in younger vegetarian or omnivores, adjusting for SBP, age, and heart rate. This suggests that maintaining an optimal level of Hcy may be important in preventing atherosclerosis in vegetarians. With the comprehensive health examination, dietary and lifestyle measurements, and biological specimen; future follow-up on disease occurrence and mortality will be valuable in determining (1) health outcome, (2) nutritional recommendation, and (3) optimal biomarker ranges, for the vegetarian population in Taiwan and in Asia.
Pros and cons of vegetarian nutrition in Slovak population
Zora Krivošíková, RND, PhD | Mini-Symposium: Vegetarian studies: A global perspective
The biggest shift to alternative nutrition - vegetarianism occurred in Slovakia after the change of the political system in 1989. According to the European Vegetarian Union, there were estimated about 54,000 vegetarians (1% of the population) in Slovakia in 2007. There was initially the tendency to veganism or lacto-ovo vegetarianism but it is mainly semivegetarianism nowadays. The research about the impact of the vegetarian diet on health in Slovakia has been run mainly by nutrition group from The Slovak Medical University in Bratislava. There is an overview of their results from the years 1994 to 2012.
The results from adult vegans showed several health risks such as vitamin B12 deficiency, mild hyperhomocysteinemia, iron and calcium deficiency, low intake of methionine, hypoproteinemia, low content of n-3 fatty acids, iodine deficiency, higher cadmium and NeCarboxymethyl-lysine content in blood. Lower bone mass density was also confirmed in the association with higher homocysteine levels in postmenopausal vegetarian women. There were found hyposiderinaemia, hypoalbuminaemia, vitamin B12 deficiency, mild hyperhomocysteinemia, reduced plasma content of eicosapentenoic and docosahexaenoic acid in children on vegan or vegetarian diets in comparison to children on mixed diet. On the other hand, there were found some unquestionable beneficial effects of vegetarian diet such as lower BMI, higher plasma concentrations of antioxidative vitamins, significantly reduced concentrations of total and LDL-cholesterol, triacylglycerols, oxidized purines and pyrimidines, insulin as well as the values of atherogenic index and insulin resistance.
Based on the identified health risks, the vegan diet is considered to be risky for both adults and children. On the contrary, semivegetarian diet that is enriched with eggs, milk and dairy products, poultry and fish seems to be without the risk. Therefore we consider enriching the traditional diet with the positive principles of the vegetarian diet to be beneficial in times when there is a need to reduce free radical diseases, particularly cardiovascular diseases and cancer.
Vegetarian diets among Latin Americans: Past, present and future
Julio Acosta Navarro, MD, PhD | Mini-Symposium: Vegetarian studies: A global perspective
The native people of Latin America have different ethnical origins and high rates of internal migration. The immigrants coming from Europe, Asia and Africa in several waves also have contributed to define communities with the original profile, not only in terms of genetic, but also with respect to several nutritional habits and lifestyles. This is the reason of the importance of research in these people. Actual scientific evidence gives us a sight into ancient American food habits which apparently varies. The first reports of Mesoamerican diet before the Spanish conquest led contemporary Europeans to believe that “the style of life is so frugal that the Hermists in the desert could not live with more sobriety”. We present the main studies in Latin America about the relation between vegetarian diet and health. In 1964 Pazzanese examined clinically 53 Indians with a predominantly vegetarian diet and high level of physical activity, living in Brazil and they observed very low values for serum lipids and no evidence of atheroesclerosis. In 1966 Netto observed lower levels of LDL in 53 natives of Xingu River jungle with a predominantly vegetarian diet and high level of physical activity. In 1968 Ruiz and Peńaloza reported on the blood pressure of Peru’s highlanders with a predominantly vegetarian diet. In the Lima Study (1997) and the Săo Paulo Study (2001) we compared the prevalence of cardiovascular risk factors among vegetarians, semi-vegetarians and omnivorous subjects. All these studies do not find evidences of overt nutritional deficiencies in the vegetarian groups investigated. De Carvalho observed that excessive meat intake was associated with poorer diet quality and dangerous impact on the environment due to deforestation for livestock grazing, emission of greenhouse gases and water pollution. At present, the CARVOS Study from Săo Paulo University is a mini-thematic project that is running.
Health benefits of plant n-3 fatty acids
Sujatha Rajaram, DrPH | Symposium: Are all n-3 fatty acids created equal?
Alpha-linolenic acid (ALA, 18:3 n-3) is an essential plant derived n-3 fatty acid that is found in foods such as flaxseed, walnuts, canola and soybean oils. While ALA is converted in the human body to longer chain n-3 fatty acids including EPA and DHA, there are clearly independent health benefits for ALA which often times get overlooked. As important it is to address the question of biological equivalence of plant derived ALA and the marine n-3 fatty acids EPA and DHA, it is equally important to address the direct health benefirs of ALA and whether or not the current western diets help achieve adequate status of ALA. This review will discuss the gap between the recommended dietary intake of ALA and the current in take in the US population and also consider the adequacy of the current recommendations. Further, the independent health benefits of ALA will be discussed with evidence from epidemiological and clinical studies. These health effects will go beyond their impact via the conversion to the longer chain n-3 fatty acids. There is some evidence to suggest a role for ALA in reducing the risk of coronary heart disease and type 2 diabetes. The evidence for this and potential mechanisms will be discussed in this presentation.
Achieving adequate n-3 fatty acid status: How to go about it
William S. Harris, PhD | Symposium: Are all n-3 fatty acids created equal?
Higher intakes and blood levels of the long-chain omega-3 fatty acids (EPA and DHA) has been shown to reduce risk for cardiovascular disease and to possibly slow neurocognitive decline. For non-vegetarians, this can be easily achieved by taking fish oil supplements or eating more fish, but for vegetarians, the options are more limited. Alpha-linolenic acid (ALA), naturally present in certain seed oils, is converted to both EPA and DHA but at very low rates. The extent to which lower intakes of the omega-6 fatty acid linoleic acid (LA) could facilitate conversion of ALA to EPA and DHA is controversial. Strategies involving genetic engineering of either soybeans (to produce oils rich in stearidonic acid, SDA) or yeast (to produce EPA), or identifying strains of microalgae that produce EPA and/or DHA are all potential solutions to improving omega-3 nutrition in vegetarians.
Plant vs. marine n-3 fatty acids and cardiovascular outcomes: What is the verdict?
Thomas Sanders, PhD, DSc | Symposium: Are all n-3 fatty acids created equal?
Linolenic acid (18:3n-3) is regarded as an essential nutrient whereas its long chain derivatives such as eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) are regarded as non-essential because they can be derived from it. The consumption of preformed long-chain n-3 fatty acids have different physiological effects from those of linolenic acid because of their longer chain length but these effects on cardiovascular risk factors are observed with intakes in excess of 1.8g/d or more which is well beyond the range of intake in most human diets. Meta-analysis of prospective cohort studies indicate a lower risk of CHD associated with increasing intakes of linolenic acid as well as long-chain n-3 PUFA. Increased intakes of both linolenic acid and long-chain n-3 fatty acids have been reported to have favourable outcomes in some studies but a recent meta-analysis of randomized controlled trials indicated no additional benefit of long-chain n-3 PUFA for patients with pre-existing CHD whose blood lipids and blood pressure are well managed. Vegetarians and vegans have virtually no long-chain n-3 fatty acid intake and although proportions of DHA are lower in the blood and tissues of omnivores especially in vegans, the levels are in a steady state. The cardiovascular risk profile of vegetarians and vegans is much more favourable than omnivores because of substantially lower LDL cholesterol concentrations, lower body mass index and moderately lower blood pressure. Arterial ageing as measured by arterial stiffness appears lower in vegans than in omnivores. A recent UK study has found lower incident CHD in vegetarians compared with omnivores. Present evidence does not justify advice to vegetarians and vegans to consume long-chain n-3 fatty acids. In the meantime dietary advice should focus on ensuring that intakes of linolenic acid not less than 0.5% energy.
Plant based diets in the prevention of heart disease and diabetes: Findings from PREDIMED
Miguel Ángel Martínez González, MD, PhD, MPH | Symposium: Vegetarian diet patterns and cardiometabolic syndrome
Observational cohort studies and a secondary prevention trial have reported an inverse association between Mediterranean diet adherence and cardiovascular risk, but no randomized trial has ever tested this dietary pattern for the primary prevention of cardiovascular events.
METHODS: In a multicenter, controlled trial, we randomly assigned 7447 participants (55 to 80 years of age; women, 57%) at high cardiovascular risk, but no cardiovascular disease at enrolment, to one of three diets: Mediterranean diet supplemented with extra-virgin olive oil, Mediterranean diet supplemented with mixed nuts, or control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small non-food gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke or cardiovascular death).
RESULTS: The two Mediterranean diet groups achieved good adherence to the intervention based on self-reported intakes and biomarker analyses. The results of an interim analysis prompted stopping the trial after a median follow-up of 4.8 years. A major cardiovascular event occurred in 288 participants. The multivariable-adjusted hazard ratios (95% confidence intervals) were 0.70 (0.54 to 0.92) and 0.72 (0.54 to 0.96) for the Mediterranean diet with virgin olive oil (96 events) and Mediterranean diet with nuts groups (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported.
CONCLUSIONS: In subjects at high cardiovascular risk, Mediterranean diets supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events.
Vegetarian diets for blood lipid management: An Eco-Atkins perspective
Cyril Kendall, PhD | Symposium: Vegetarian diet patterns and cardiometabolic syndrome
Vegan and vegetarian diets are associated with lower LDL-C and reduced rates of coronary heart disease (CHD) in cohort studies and with reduced progression of CHD and improved diabetes control in clinical studies. Furthermore, a number of plant food components including vegetable proteins, vegetable oils, viscous fibers, plant sterols and nuts have been shown individually to reduce serum lipids in many studies and collectively in the portfolio diet have been shown to produce statin-like reductions in LDL-C. However, one of the greatest public health concerns related to cardiometabolic health is the increasing incidence of overweight and obesity and determining the most effective diets to achieve optimal body weight has received considerable attention. In this regard, low-carbohydrate diets have become widely popular (e.g. Atkins, South Beach, Zone) and have had success when good compliance is achieved. However, animal products are high in saturated fat and cholesterol, and there is concern that they may negatively affect blood lipids. Some studies have found that even during active weight loss on high saturated fat diets, LDL-C may rise above baseline and there is concern that if such diets continue to be eaten when weight loss has ceased, a more atherogenic blood lipid profile may result. These concerns have prompted exploration of other weight loss strategies. While a Mediterranean weight loss diet reported only modest reductions in LDL-C, a cohort study found that low-carbohydrate diets, high in vegetable oils and proteins, was associated with reduced CHD events and incidence of diabetes in women. We have conducted clinical studies to further assess the effects of low-carbohydrate vegetarian diets for weight loss and CHD risk factors and found that a low-carbohydrate diet, high in vegetable proteins and oils, had lipid-lowering advantages over a high-carbohydrate, low fat weight loss diet, and improved other CHD risk factors.
Anti-inflammatory life style for prevention and treatment of cancer and other chronic diseases: Facts and fiction
Bharat Aggarwal, PhD | Symposium: Vegetarian diet patterns and cardiometabolic syndrome
Chronic infections, obesity, alcohol, tobacco, radiation, environmental pollutants, and high-calorie diets have been recognized as major risk factors for the most chronic diseases, including cancer. All these risk factors are linked to chronic diseases through inflammation. While acute inflammation that persists for short-term mediates host defense against infections, chronic inflammation that lasts for long-term can predispose that host to various chronic illnesses, including cancer. Linkage between cancer and inflammation is indicated by numerous lines of evidence: first, transcription factors NF-kB and STAT3, two major pathways for inflammation, are activated by most cancer risk factors; second, an inflammatory condition preceded most cancers; third, NF-kB and STAT3 are constitutively active in most cancers; fourth, hypoxia and acidic conditions found in solid tumors activate NF-kB; fifth, chemotherapeutic agents and gamma-irradiation activate NF-kB and lead to chemoresistance; sixth, most gene products linked to inflammation, survival, proliferation, invasion, angiogenesis, and metastasis are regulated by NF-kB and STAT3; seventh, suppression of NF-kB and STAT3 inhibits the proliferation and invasion of tumors; and eighth, most chemopreventive agents mediate their effects through inhibition of NF-kB and STAT3 activation pathways. Thus, suppression of these proinflammatory pathways may provide opportunities for both prevention and treatment of cancer. We will discuss the potential of various dietary agents, also called nutraceuticals derived from spices, lentils, nuts, fruits, and vegetables: and agents from traditional Ayurvedic medicine in suppression of inflammatory pathways and their role in prevention and therapy of cancer and other chronic diseases.
Gut microbiota and health outcomes: Influence of diet patterns
Julia Wong, PhD, RD | Symposium: Vegetarian diet patterns and cardiometabolic syndrome
Modulation of the gut microbiota is an area of growing interest, particularly for its link to improving and maintaining the systemic health of the host. It has been suggested to have the potential to reduce risk factors associated with chronic diseases. Emerging evidence also suggests a potential link between interindividual differences in the gut microbiota and variations in physiology or predisposition to certain chronic disease risk factors. Studies of those following vegetarian and vegan diets have been associated with reduced risk of CHD events and incidence of diabetes. Plant-based diets may promote a more favorable gut microbial profile. Such diets are high in dietary fiber and fermentable substrate (i.e. non-digestible or undigested carbohydrates) which are sources of metabolic fuel for gut microbial fermentation, which in turn, result in end products that may be utilized by the host (e.g. short chain fatty acids). These end products may have direct or indirect effects on modulating the health of its host. Alterations in the gut microbiota may also stimulate certain populations and may assist in biotransformation of bioactive components found in plant foods. Strategies to modify microbial communities may therefore provide a novel approach in the treatment and management of chronic diseases.
Sustainability of Plant-based Diets: Back to the Future
Joan Sabaté, MD, DrPH | Plenary Address: Tuesday, February 26, 2013
Sustainable diets have low environmental impacts while contributing to nutrition security and to healthy life for present and future generations. For millennia mankind has obtained the necessary food for its sustenance in a sustainable manner. Presently this is not the case. Against the backdrop of current worldwide population growth, particularly the rise of the middle class and its appetite for foods of animal origin, current global food production and consumption patterns are not sustainable. Scientists have recently shown that we have already trespassed several of the safety boundaries that govern planetary homeostasis, including loss of biodiversity and climate change. Recent reports have recognized the connections between the food system, consumption patterns and climate change. The modern food industrial sector, especially livestock production, accounts for 20-50% of global greenhouse-gas emissions, thus contributing to climate change and its adverse environmental and health consequences. Modifying food production practices will contribute toward decreasing the environmental footprint of the food system. However, changing consumer demands and food choices to plant-based diets will more effectively achieve climate stabilization goals and reduce resource utilization. The time has come to seriously consider educating the general population to reduce the consumption of meat and other animal products in their diet, a shift which is likely to result in better health outcomes, while sustaining the long-term health of the biosphere.
Protein production: Planet, profit or people?
Harry Aiking, PHD, ERT | Symposium: Efficiency and environmental aspects of meatless diets
Food sustainability and food security are increasingly in the spotlight. According to FAO projections we will need to nearly double food production in the next four decades. This paper argues that protein production and consumption are pivotal, for anthropogenic contributions to the nitrogen cycle are 100-200% (compared to 1-2% to the carbon cycle), with biodiversity as the main casualty. Since 1 kg animal protein requires circa 6 kg plant protein, its production is a major driver of biodiversity loss, freshwater depletion, climate change, eutrophication, and incidence of emerging diseases, such as avian influenza. Therefore, a reversed diet transition back to more plant protein could really make a difference. Historically, human protein sources depended on soil, climate and ecology. During the 20th century a diet transition from plant to animal proteins took place in Europe. Interestingly, the latter are surrounded by an aura of social and cultural traditions. An overview of diet proteins in EU-15 member states is used to illustrate the current diversity and the underlying forces that shaped it. European countries such as the UK, Sweden and the Netherlands have published policy reports addressing food security, sustainability and health combined. The food industry is focussing on food safety and increasingly on sustainability. An important issue is consumer communication, because their “framing” is radically different from those of governmental and industrial policymakers. There is no “one size fits all”. Evidently, a huge range of differences exist between countries and between distinct groups of consumers within countries. In summary, making consumers change their diets into a more sustainable direction will not be a piece of cake.
Evaluating the global warming mitigation potential of healthy vegetarian dietary patterns
Samuel Soret, PhD, MPH | Symposium: Efficiency and environmental aspects of meatless diets
Worldwide, agricultural activities account for about 20-50% of total greenhouse gas emissions (GHGEs), thus contributing to climate change and its adverse environmental and health consequences. According to recent estimates, 80% of GHGEs of all food production arises from livestock. Hence, the carbon footprint of vegetarian diets appears to be substantially lower compared to meat-based diets. The key objective of this study is to advance a methodology for realistically quantifying the GHGEs resulting from meat-based and meatless whole dietary patterns in a healthy population. We compare five dietary patterns identified in the Adventist Health Study (AHS) population: vegan, lacto-ovo-vegetarian, semi-vegetarian, pesco-vegetarian, and omnivorous. We implemented an energy analysis methodology to calculate emission intensities across the various stages of the life cycle of foods as actually consumed by the subjects. We employed the SimaPro7 software to calculate the CO2 and non-CO2 GHGEs. Using AHS individual-level data; we also assessed the differences in health outcomes across the examined dietary groups. In addition, to place the magnitude of the GHGEs footprint of dietary choices in a broader context, we discuss comparative scenarios related to common human activities, such as the number of miles driven annually by a person. Our analyses show non-trivial differences in greenhouse gas intensities with respect to dietary patterns. These differences highlight the potential of plant-based diets in the mitigation of climate change.
Is iron and zinc nutrition a concern for vegetarian infants and young children
Rosalind Gibson, PhD, FRSNZ | Symposium: Foods and nutrients of interest to vegetarians: The science and application
With the growing number of fortified plant-based foods, well-planned vegetarian diets are considered adequate for all stages of the lifecycle, despite limited data on the zinc status of vegetarians during early childhood. Bioavailability of zinc and iron in vegetarian diets is poor, because of their higher content of absorption inhibitors such as phytate and polyphenols, and the absence of flesh foods. Consequently, vegetarians during childhood often have lower serum ferritin concentrations (indicative of reduced iron stores) than omnivores, despite comparable intakes of total iron; hemoglobin differences are small, and rarely associated with anemia. However, serum zinc data are sparse and difficult to interpret because recommended analytical procedures have not been followed. Adolescent data suggest zinc deficiency is likely in some vegetarian children, although growth appears normal; more subtle clinical consequences have not been investigated. Fortified foods consumed by vegetarian children are more likely to reduce iron deficiency than zinc deficiency. In some vegetarian immigrants from low income households, non-dietary factors such as genetic hemoglobin disorders, chronic inflammation, overweight, and parasitic infections may predispose them to iron and zinc deficiency. To reduce their risk, the content and bioavailability of iron and zinc should be enhanced in vegetarian diets by consumption of leavened whole grains, fermented soy foods, sprouted legumes, and cereals and toddler milk drinks fortified with bioavailable iron; soaking dried legumes before cooking; and replacing tea and coffee consumed with meals by vitamin C-rich drinks, fruits or vegetables. Supplements may be necessary for those following very restricted vegetarian diets.
The vitamin B12 story: Why is it still a concern?
Ella Haddad, DrPH, RD | Symposium: Foods and nutrients of interest to vegetarians: The science and application
As the only known naturally available biomolecule with a stable metal-carbon bond, vitamin B12 is one of the most important molecules in food and human nutrition. The purpose of this presentation is to review why B12 continues to be a nutrient of concern for both vegetarians and non-vegetarians alike and to interpret findings from the Adventist Health Study 2 (AHS-2) on the B12 status of participants. Blood concentrations of active B12 (holotranscobalamin) were obtained from >900 participants of the Calibration Study arm of AHS-2. The prevalence of low B12 status among vegans, lacto-ovo vegetarians and non vegetarians was approximately 6.8%, 7.5% and 7.9% respectively. Our data suggests that factors other than animal food intake impact human B12 status.
Bone nutrients for vegetarians
Reed Mangels, PhD, RD, LDN, FADA | Symposium: Foods and nutrients of interest to vegetarians: The science and application
The process of bone mineralization and resorption is complex and is affected by numerous factors, including dietary constituents. Although some dietary factors involved in bone health, such as calcium and vitamin D, are typically associated with dairy products, plant-based sources of these nutrients also supply other key nutrients involved in bone maintenance. Some research suggests that vegetarian diets, especially vegan diets, are associated with lower bone mineral density (BMD) but this does not appear to be clinically significant. Vegan diets are not associated with an increased fracture risk, provided calcium intake is adequate. Dietary factors in plant-based diets that support the development and maintenance of bone mass include calcium, vitamin D, protein, potassium, magnesium, vitamin K, and soy isoflavones. Other factors present in plant-based diets such as phytates, fiber, oxalates, and sodium can potentially interfere with absorption and retention of calcium and thereby have a negative effect on BMD. The role of protein in calcium balance is multifaceted. Factors to be considered in assessing protein’s effect on calcium balance include the amount and type of protein, calcium intake, other dietary constituents, and age and gender of subjects. Overall, calcium and protein intakes in accord with the Dietary Reference Intakes are recommended for vegetarians, including vegans. Fortified foods are often helpful in meeting recommendations for calcium and vitamin D. Plant-based diets can provide adequate amounts of key nutrients for bone health.
Legumes and beans: Nutrition and health benefits
Virginia Messina, MPH, RD | Symposium: Foods and nutrients of interest to vegetarians: The science and application
Legumes play an important role in traditional diets throughout the world where they are valued for their rich protein content, ease of preparation, and culinary appeal. In contrast, these foods play only a minor role in the diets of most people in North America and northern Europe. Replacing animal-derived foods with legumes in western diets would improve overall dietary quality. These foods are generally low in saturated fat, free of cholesterol and are rich in fiber as well as important micronutrients such as folate and potassium. As good sources of the essential amino acid lysine and of iron, legumes can play a particularly important role in the diets of vegetarians. Because they are rich in resistant and soluble fiber, beans can be an important component of diets aimed at reducing serum cholesterol levels and protecting against heart disease. These foods also have a low glycemic index, making them useful in diets for control of diabetes. Finally, legumes contain several biologically active non-nutritive components, such as phenolic antioxidants, which may exert beneficial effects on health. While these foods also contain anti-nutrients such as protease inhibitors, levels in properly cooked legumes are almost certainly too low to exert any adverse effects. In conclusion, their rich content of protein, fiber, micronutrients and phytochemicals, and low content of saturated fat make legumes an important component of vegetarian diets and a valuable addition to all diets aimed at reducing chronic disease.
Metabolic syndrome, insulin resistance and diabetes: does dairy help?
Peter Elwood, MD, DSc, FRCP, FFPHM | Symposium: Foods and nutrients of interest to vegetarians: The science and application
The metabolic syndrome has been termed ‘the deadly quartet’ and has been said to be the fastest growing ‘disease entity’ in the world. On the other hand, it is probably not a true syndrome but simply an elaborate risk formula. Nevertheless, a number of reports have shown negative relationships between the ‘syndrome’ and the consumption of milk or dairy products Beliefs about and dairy foods are all too often based upon associations in short term studies between the consumption of a food, such as milk, and a biochemical factor, such as cholesterol, or insulin resistance. This approach can be highly misleading, because most foods, and dairy in particular, are a complex mixture of nutrients, and these have effects on many biological mechanisms. Thus, a focus upon one biochemical factor, such as cholesterol, ignores changes in other factors, such as blood pressure. Dependable judgements about diet and health can only come from large, long-term ‘cohort’, or ‘prospective’ studies, in which large samples of subjects, for whom dietary intake and other life-style factors are recorded, are then followed forwards in time so that new disease events and deaths can be identified and related to base-line milk or diary consumption.
The very best evidence therefore come from an ‘overview’ or ‘meta-analysis’ of all the relevant cohort study. A search of the published literature identified 34 large, prospective studies on the consumption of dairy foods and associations with disease or death, seven of which gave data on the incidence of diabetes. Overviews of all these cohort studies will be presented.
Epigenetics and plant based diets: Application for clinicians
John Kelly, MD, MPH | Symposium: Foods & Nutrients of interest to Vegetarians
The epigenome is more important than the genome in the clinical application of beneficial effects from plant-based nutrition in the treatment of chronic disease. Non-coding DNA and chaperone molecules, far from being “inert filler,” play an essential role in modulating gene expression. Plant-based diets have been shown to exert powerful, long-lasting effects on gene expression via the epigenome. Helping patients and caregivers understand the power of plant nutrition to modulate gene expression in beneficial ways can have profound impact on patient health and longevity. Simple tools can have large effects in a short period of time. The practical science of applied epigenetics is revealing exciting treatment options and methods.
Self-defined vegetarian status: usefulness and validity
Timothy Key, PhD | Symposium: Classification of vegetarian dietary patterns: Panel
For large epidemiological studies, vegetarian status is generally defined using a small number of questions on usual diet. For example, in the EPIC-Oxford prospective study participants are asked four questions about whether they eat any: meat (including bacon, ham, poultry, game, meat pies and sausages); fish; dairy products (including milk, cheese, butter, yogurt); and eggs (including eggs in cakes and other baked foods). These four questions are then used to classify participants into four diet groups: meat-eaters, who eat meat, irrespective of whether they eat fish, dairy products or eggs; fish eaters, who do not eat meat but do eat fish; vegetarians, who do not eat meat or fish; and vegans, who do not eat meat, fish, dairy products or eggs. The characteristics of these four diet groups will be described, with reference to food and nutrient intakes and some plasma nutrient concentrations, together with analyses of the stability of these diet groups at approximately 5, 10 and 15 years since recruitment into EPIC-Oxford. Finally the pros and cons of this classification and possible modifications for future research will be discussed.
Definition of vegetarian status according to the absence of meat
Gary Fraser, MB ChB, PhD | Symposium: Classification of vegetarian dietary patterns: Panel
It is somewhat of a paradox that a diet pattern with the name "vegetarian" (emphasizing vegetables) should generally be thought of instead in terms of the few foods excluded (i.e. the absence of meats). Yet, despite this I believe that we should continue to embrace this label, as it has name recognition for nearly all in Western societies, and perhaps beyond. Vegetarian options in eating establishments, and in cook-books are common, well-recognized and often sought after. How often do you see Mediterranean diet options in restaurants, and how does the "man in the street" interpret this diet? The simplicity of the label and its interpretation, enables all to easily understand a basic concept --the absence of meats. But this is also an "Achilles heel". The absence of one food group cannot adequately define a dietary pattern. This leads to difficulties in comparing vegetarian research results among different societies and cultures. Secondly, it makes it difficult for authoritative groups to provide guidelines for a vegetarian diet, as the definitions are so vague, beyond the absence of meat. One initial solution would be to define and publish a Recommended U.S. Vegetarian Diet, that could most easily be patterned after the typical lacto-ovo Adventist vegetarian diet, as a starting point. This would make sense as it is the diet that at present has by far the most published evidence of broad health benefits. In the future this could quite quickly progress to a recommended European vegetarian diet, Recommended Indian vegetarian diet, Recommended U.S. vegan diet, Recommended African-American Vegetarian diet etc etc. In different communities and settings, different vegetarian foods will be available at reasonable price, there will be different cultural preferences, and different proprietary products available.
Data reduction techniques to classify plant based dietary patterns: Pros and cons
David R. Jacobs, PhD | Symposium: Classification of vegetarian dietary patterns: Panel
In statistical theory, data reduction is a method for reducing dimensionality of a multivariable problem to isolate one or a few dimensions that capture the essence of the full, multivariable data. This reduction in dimensionality enables the analyst to make simple, yet still comprehensive statements. In the field of dietary patterns, researchers initially took this perspective to reduce the complex nutritional problem encompassing many foods and nutrients consumed to a single score. They employed factor/principal components analysis. To the surprise of some, the resulting diet patterns predicted chronic disease. Recently we showed that diet patterns are stable over many years in free-living people, thereby constituting a nutritional characteristic with stability similar to that of measured characteristics such as serum cholesterol. Yet apart from broad strokes such as “I like meat” or “I am vegetarian”, diet pattern does not seem to be something that people think about. They think about food in meals over a few days, but most people do not obviously have a plan to eat in a certain pattern. Rather, diet pattern that persists over years may be an epidemiologic discovery. Issues in forming diet patterns include what foods or nutrients to include as elements of the pattern, how nuanced to make these elements, whether to combine them into groups based on gram weight, energy content, servings/day, or something else, how to combine across groups, and whether the rules that connect all these elements should be data-driven or a priori. Classification of plant-based diets into patterns may be able to capture nuances that are not accessible when plant food consumption is low. Several similar diet patterns all predict chronic disease. Methods are needed to compare and contrast these patterns in order to form an enhanced, even better, pattern.