Vegetarian diets and incidence of diabetes in the Adventist Health Study-2

Diet and longevity: The effects of traditional eating habits on human lifespan extension

Since the dawn of time human beings have been trying to improve the quality of the existence and extend their lifespan. Genetic, environmental, behavioral and dietary factors influence the pathways that regulate aging and life expectancy, thus rendering longevity a very complex phenomenon. Although a long-lived elixir has not yet been found, physicians and scientists agree that nutrition has a major impact on the overall mortality and morbidity, hence becoming the subject of a widespread scientific research. This review describes, analyzes and compares the effects of different types of diets in reducing the onset of typical Western countries non-communicable diseases (NCDs) (cardiovascular diseases, tumors, chronic respiratory diseases, diabetes, etc.), thus increasing the average lifespan. It will first depict the most relevant characteristics, nutraceutical properties and effects on the populations of the Mediterranean, Japanese, Vegetarian and New Nordic Diet. Finally, it will describe the impact of different dietary restrictions in modulating the genetic pathways that regulate metabolism and aging. Overall, this work reinforces the evidence that specific eating habits, in addition to healthy and active lifestyles, are crucial to increase people’s health span and to achieve an optimal longevity.

Rate of appearance of amino acids after a meal regulates insulin and glucagon secretion in patients with type 2 diabetes: a randomized clinical trial

Background

Meal composition regulates the postprandial response of pancreatic and gastrointestinal hormones and plays an important role in patients with type 2 diabetes (T2D). Proteins have glucagon and insulinotropic effects, which may differ depending on amino acid composition, form of intake, and rate of digestibility and absorption.

Objective

The aim of this study was to test effects of isolated pea protein-based (PP) compared with casein protein-based (CP) meals differing in amino acid compositions on endocrine responses to meal tolerance tests (MTTs) in patients with T2D.

Design

Thirty-seven individuals with T2D [mean ± SD age: 64 ± 6 y; mean ± SD body mass index (kg/m2): 30.2 ± 3.6; mean ± SD glycated hemoglobin: 7.0% ± 0.6%] were randomly assigned to receive either high-animal-protein (∼80% of total protein) or high-plant-protein (∼72% of total protein) diets (30% of energy from protein, 40% of energy from carbohydrate, 30% of energy from fat) for 6 wk. MTTs were performed at study onset and after 6 wk. Participants received standardized high-protein (30% of energy) meals 2 times/d containing either CP-rich (∼85% wt:wt) or PP-rich (∼95% wt:wt) foods.

Results

The CP and PP meals produced differences in insulin, C-peptide, glucagon, and glucose-dependent insulinotropic peptide (GIP) release. Total areas under the curve after CP were significantly lower than after the PP lunch by 40% for insulin and 23% for glucagon. Indexes of insulin sensitivity and secretion were significantly improved for the second CP MTT. This was accompanied by differential rates of appearance of amino acids. The ingestion of PP resulted in significant increases in amino acids after both meals, with a decline between meals. By contrast, CP intake resulted in increases in most amino acids after breakfast, which remained elevated but did not increase further after lunch.

Conclusions

PP elicits greater postprandial increases in glucagon than does CP and consequently requires higher insulin to control glucose metabolism, which appears to be related to the rate of amino acid appearance. The metabolic impact of protein quality could be used as a strategy to lower insulin needs in patients with T2D. This trial was registered at www.clinicaltrials.gov as NCT02402985.

Flexitarian Diet and Weight Control: Healthy or Risky Eating Behavior?

A carefully planned vegetarian diet meets nutrition recommendations by providing essential nutrients and lowering levels of saturated fat and cholesterol. Because balanced diets that limit or exclude meat tend to be lower in calories than omnivorous diets, it has been suggested that vegetarian eating patterns may be motivated by weight control. This view has been supported by findings demonstrating that vegetarians have a higher rate of disordered and restrained eating than non-vegetarians. Other findings suggest that weight control is a primary reason identified by adolescents and young adults for eliminating items such as meat and other animal products from their diet. Thus, it has been suggested that vegetarianism may provide a socially acceptable means to control body weight. However, this may be an over-generalization. Vegetarians are a heterogeneous group of individuals with radically different eating habits. Moreover, they are often compared to omnivores who eat meat on a regular basis. These omnivorous eating habits do not represent a growing subset of the population, many of whom are adopting a flexitarian diet that involves only the occasional consumption of meat. The goal of the current paper will be to demonstrate that semi-vegetarians and flexitarians are categorically different from vegans, lacto-ovo-vegetarians, and omnivores and describe the motivations as well as the positive and negative health implications that are associated with dietary patterns that limit the intake of meat. It is important for us to understand the motivations and behaviors that are characteristic of flexitarians in order to develop effective evidence-based strategies to address unhealthy eating behaviors.

Advancing Health Equity With Lifestyle Medicine

The Optimal Health and Wellness Clinic of Morehouse Healthcare seeks to advance health equity by providing lifestyle medicine services to its predominantly African American patient population. Health equity means eliminating health disparities by providing services that meet the needs of the population served. African Americans have a higher burden of cardiovascular disease and diabetes than other American ethnic groups. Recent evidence indicates that eating a plant-based diet may eliminate disparities in cardiovascular disease and diabetes. The clinic provides lifestyle intervention services such as stress and sleep management, but the focus is on helping patients to adopt and maintain a plant-based diet. A range of encounter options that include shared medical appointments and cooking classes are offered. The clinic is an example of a lifestyle medicine specialty practice within the multispecialty practice arm of a medical school. The shared mission to promote health equity provides substantial resources to the clinic and allows for collaborative efforts to improve the health of the community.

Plant versus animal based diets and insulin resistance, prediabetes and type 2 diabetes: the Rotterdam Study

Vegan or vegetarian diets have been suggested to reduce type 2 diabetes (T2D) risk. However, not much is known on whether variation in the degree of having a plant-based versus animal-based diet may be beneficial for prevention of T2D. We aimed to investigate whether level of adherence to a diet high in plant-based foods and low in animal-based foods is associated with insulin resistance, prediabetes, and T2D. Our analysis included 6798 participants (62.7 ± 7.8 years) from the Rotterdam Study (RS), a prospective population-based cohort in the Netherlands. Dietary intake data were collected with food-frequency questionnaires at baseline of three sub-cohorts of RS (RS-I-1: 1989–1993, RS-II-1: 2000–2001, RS-III-1: 2006–2008). We constructed a continuous plant-based dietary index (range 0–92) assessing adherence to a plant-based versus animal-based diet. Insulin resistance at baseline and follow-up was assessed using homeostasis model assessment of insulin resistance (HOMA-IR). Prediabetes and T2D were collected from general practitioners’ records, pharmacies’ databases, and follow-up examinations in our research center until 2012. We used multivariable linear mixed models to examine association of the index with longitudinal HOMA-IR, and multivariable Cox proportional-hazards regression models to examine associations of the index with risk of prediabetes and T2D. During median 5.7, and 7.3 years of follow-up, we documented 928 prediabetes cases and 642 T2D cases. After adjusting for sociodemographic and lifestyle factors, a higher score on the plant-based dietary index was associated with lower insulin resistance (per 10 units higher score: β = −0.09; 95% CI: − 0.10; − 0.08), lower prediabetes risk (HR = 0.89; 95% CI: 0.81; 0.98), and lower T2D risk [HR = 0.82 (0.73; 0.92)]. After additional adjustment for BMI, associations attenuated and remained statistically significant for longitudinal insulin resistance [β = −0.05 (− 0.06; − 0.04)] and T2D risk [HR = 0.87 (0.79; 0.99)], but no longer for prediabetes risk [HR = 0.93 (0.85; 1.03)]. In conclusion, a more plant-based and less animal-based diet may lower risk of insulin resistance, prediabetes and T2D. These findings strengthen recent dietary recommendations to adopt a more plant-based diet.

Clinical Trial Registry number and website NTR6831, http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=6831.

Vegetarian Dietary Patterns and Cardiovascular Disease

Cardiovascular (CV) disease (CVD) is the leading global cause of mortality, being responsible for 46% of non-communicable disease deaths. It has been estimated that about 85.6 million Americans are living with some form of CVD, which continues to rise. Healthy lifestyle choices may reduce the risk of myocardial infarction by >80%, with nutrition playing a key role. Vegetarian dietary patterns reduce CVD mortality and the risk of coronary heart disease (CHD) by 40%. Plant-based diets are the only dietary pattern to have shown reversal of CHD. Additionally, evidence suggests benefits of vegetarian dietary patterns in both the prevention and the treatment of heart failure and cerebrovascular disease. Plant-based diets are associated with lower blood pressure, lower blood lipids, and reduced platelet aggregation than non-vegetarian diets and are beneficial in weight management, reduce the risk of developing metabolic syndrome, and type 2 diabetes. They have also been shown an effective treatment method in diabetes management. Well planned vegetarian diets provide benefits in preventing and reversing atherosclerosis and in decreasing CVD risk factors and should be promoted through dietary guidelines and recommendations.

Vegetarian diet, change in dietary patterns, and diabetes risk: a prospective study

Background/objectives

Vegetarian diets are inversely associated with diabetes in Westerners but their impact on Asians—whose pathophysiology differ from Westerners—is unknown. We aim to investigate the association between a vegetarian diet, change in dietary patterns and diabetes risk in a Taiwanese Buddhist population.

Methods

We prospectively followed 2918 non-smoking, non-alcohol drinking Buddhists free of diabetes, cancer, and cardiovascular diseases at baseline, for a median of 5 years, with 183 incident diabetes cases confirmed. Diet was assessed through a validated food frequency questionnaire at baseline and a simple questionnaire during follow-ups. Incident cases of diabetes were ascertained through follow-up questionnaires, fasting glucose and HbA1C. Stratified Cox Proportional Hazards Regression was used to assess the effect of diets on risk of diabetes.

Results

Consistent vegetarian diet was associated with 35% lower hazards (HR: 0.65, 95% CI: 0.46, 0.92), while converting from a nonvegetarian to a vegetarian pattern was associated with 53% lower hazards (HR: 0.47, 95% CI: 0.30, 0.71) for diabetes, comparing with nonvegetarians while adjusting for age, gender, education, physical activity, family history of diabetes, follow-up methods, use of lipid-lowering medications, and baseline BMI.

Conclusion

Vegetarian diet and converting to vegetarian diet may protect against diabetes independent of BMI among Taiwanese.

Assessing the Influence of Vegan, Vegetarian and Omnivore Oriented Westernized Dietary Styles on Human Gut Microbiota: A Cross Sectional Study

Diet and lifestyle have a strong influence on gut microbiota, which in turn has important implications on a variety of health-related aspects. Despite great advances in the field, it remains unclear to which extent the composition of the gut microbiota is modulated by the intake of animal derived products, compared to a vegetable based diet. Here the specific impact of vegan, vegetarian, and omnivore feeding type on the composition of gut microbiota of 101 adults was investigated among groups homogeneous for variables known to have a role in modulating gut microbial composition such as age, anthropometric variables, ethnicity, and geographic area. The results displayed a picture where the three different dietetic profiles could be well distinguished on the basis of participant's dietetic regimen. Regarding the gut microbiota; vegetarians had a significantly greater richness compared to omnivorous. Moreover, counts of Bacteroidetes related operational taxonomic units (OTUs) were greater in vegans and vegetarians compared to omnivores. Interestingly considering the whole bacterial community composition the three cohorts were unexpectedly similar, which is probably due to their common intake in terms of nutrients rather than food, e.g., high fat content and reduced protein and carbohydrate intake. This finding suggests that fundamental nutritional choices such as vegan, vegetarian, or omnivore do influence the microbiota but do not allow to infer conclusions on gut microbial composition, and suggested the possibility for a preferential impact of other variables, probably related to the general life style on shaping human gut microbial community in spite of dietary influence. Consequently, research were individuals are categorized on the basis of their claimed feeding types is of limited use for scientific studies, since it appears to be oversimplified.

Plant-based diets and cardiovascular health

Plant-based diets, defined in terms of low frequency of animal food consumption, have been increasingly recommended for their health benefits. Numerous studies have found plant-based diets, especially when rich in high quality plant foods such as whole grains, fruits, vegetables, and nuts, to be associated with lower risk of cardiovascular outcomes and intermediate risk factors. This review summarizes the current evidence base examining the associations of plant-based diets with cardiovascular endpoints, and discusses the potential biological mechanisms underlying their health effects, practical recommendations and applications of this research, and directions for future research. Healthful plant-based diets should be recommended as an environmentally sustainable dietary option for improved cardiovascular health.

Protective role of physical activity on type 2 diabetes: Analysis of effect modification by race-ethnicity

BACKGROUND

It is well known physical activity (PA) plays a role in the prevention of type 2 diabetes (T2D). However, the extent to which PA may affect T2D risk among different race-ethnic groups is unknown. Therefore, the aim of the present study was to systematically examine the effect modification of race-ethnicity on PA and T2D.

METHODS

The PubMed and Embase databases were systematically searched through June 2016. Study assessment for inclusion was conducted in three phases: title review (n = 13 022), abstract review (n = 2200), and full text review (n = 265). In all, 27 studies met the inclusion criteria and were used in the analysis. Relative risks (RRs) and 95% confidence intervals (CIs) were extracted and analyzed using Comprehensive Meta-Analysis software. All analyses used a random-effects model.

RESULTS

A significant protective summary RR, comparing the most active group with the least active PA group, was found for non-Hispanic White (RR 0.71, 95% CI 0.60-0.85), Asians (RR 0.76, 95% CI 0.67-0.85), Hispanics (RR 0.75, 95% CI 0.64-0.89), and American Indians (RR 0.73, 95% CI 0.60-0.88). The summary effect for non-Hispanic Blacks (RR 0.91, 95% CI 0.76-1.08) was not significant.

CONCLUSIONS

The results of the present study indicate that PA (comparing most to least active groups) provides significant protection from T2D, with the exception of non-Hispanic Blacks. The results also indicate a need for race-ethnicity-specific reporting of RRs in prospective cohort studies that incorporate multiethnic samples.

Effectiveness of plant-based diets in promoting well-being in the management of type 2 diabetes: a systematic review

Diet interventions have suggested an association between plant-based diets and improvements in psychological well-being, quality of life and glycated hemoglobin (HbA1c) control in populations with diabetes. The aims of this review are to systematically analyze the available literature on plant-based diet interventions targeting diabetes in adults and to clearly define the benefits on well-being of such interventions. This is a systematic review of controlled trials. A computerized systematic literature search was conducted in the following electronic databases: Allied and Complementary Medicine, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, E-Journals, Excerpta Medica Database, MEDLINE, Health Management Information Consortium, PsycARTICLES, PsycINFO, PubMed, SocINDEX and Web of Science. The search strategy retrieved 1240 articles, of which 11 met the inclusion criteria (n=433; mean sample age 54.8 years). Plant-based diets were associated with significant improvement in emotional well-being, physical well-being, depression, quality of life, general health, HbA1c levels, weight, total cholesterol and low-density lipoprotein cholesterol, compared with several diabetic associations' official guidelines and other comparator diets. Plant-based diets can significantly improve psychological health, quality of life, HbA1c levels and weight and therefore the management of diabetes.

Long-chain n-3 PUFA in vegetarian women: a metabolic perspective

Vegetarian diets have been associated with health benefits, but paradoxically are low in EPA and DHA which are important for development, particularly of the central nervous system, and for health. Humans have limited capacity for synthesis of EPA and DHA from α-linolenic acid, although this is greater in women than men. Oily fish and, to a lesser extent, dairy foods and meat are the primary sources of EPA and DHA in the diet. Exclusion of these foods from the diet by vegetarians is associated consistently with lower EPA and DHA status in vegetarian women compared with omnivores. The purpose of the present review was to assess the impact of low EPA and DHA status in vegetarian pregnancies on the development and health of children. EPA and DHA status was lower in breast milk and in infants of vegetarian mothers than those born to omnivore mothers, which suggests that in the absence of pre-formed dietary EPA and DHA, synthesis from α-linolenic acid is an important process in determining maternal EPA and DHA status in pregnancy. However, there have been no studies that have investigated the effect of low maternal DHA status in vegetarians on cognitive function in children. It is important to address this gap in knowledge in order to be confident that vegetarian and vegan diets during pregnancy are safe in the context of child development.

A New Approach to Assess Lifetime Dietary Patterns Finds Lower Consumption of Animal Foods with Aging in a Longitudinal Analysis of a Health-Oriented Adventist Population

Life-course diet patterns may impact risk of disease, but little is known about dietary trends with aging. In a retrospective longitudinal analysis we estimated lifetime intake of animal products and adherence to vegetarian dietary patterns among 51,082 Adventist Health Study-2 (AHS-2) subjects using data from a reliable life-course dietary (meats, dairy, eggs) questionnaire. Results showed a marked tendency to consume fewer animal products (in total) in older years and to reduce consumption of meat, poultry and fish, but not eggs or dairy. Among the 29% of elderly subjects who during their lifetime kept the same dietary pattern (LTS) were: LTS-vegans (1.1%), LTS-lacto-ovo vegetarians (31.2%), LTS-pesco vegetarians (0.49%), LTS-semi vegetarians (3.7%), and LTS-non-vegetarians (63.5%). Among the 71% of switchers were “Converters” (59.7%) who moved towards and “Reverters” (9.1%) who moved away from vegetarian diets, and Multiverters (31.2%), who had moved in both directions. LTS-non-vegetarians, and also reverters, were more overweight and showed a less healthy lifestyle than others. We conclude that the dietary patterns are dynamic with strong trends to reduce animal foods and to adopt more vegetarian patterns with aging. The disease experience of subjects with different lifetime dietary patterns can be compared.

Obesity, Metabolic Syndrome, and Cardiovascular Risk in Gluten-Free Followers Without Celiac Disease in the United States: Results from the National Health and Nutrition Examination Survey 2009-2014

BACKGROUND

Despite unclear benefits of gluten-free diets (GFD) in the general population, gluten-free followers without medical indications are driving the market. Few studies have investigated health benefits of GFD in the general population.

AIMS

To estimate metabolic and cardiovascular disease (CVD) risk profiles among gluten-free followers without celiac disease (CD).

METHODS

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2009-2014. There were 13,523 persons without CD who had GFD information. People with known CVD were excluded. We compared gluten-free followers without CD and the general population by selective metabolic and CVD risk profiles using survey-weighted generalized logistic regression.

RESULTS

There were 155 gluten-free followers without CD and CVD, corresponding to a weighted prevalence of 1.3% (3.2 million Americans). Gluten-free followers tended to be women and have a smaller waist circumference and higher HDL cholesterol. They also had a lower BMI with a borderline p value (0.053) and significant self-reported weight loss (-1.33 kg) over one year. Moreover, gluten-free followers were more likely to consider their weight appropriate. There was no statistical difference by age, smoking, hypertension, total cholesterol, triglyceride cholesterol, HbA1c, or fasting glucose. Despite a lower probability of having metabolic syndrome (33.0 vs 38.5%) and lower 10-year CVD risk score (4.52 vs 5.70%) in gluten-free followers, there was no statistical difference.

CONCLUSIONS

Although being on a GFD may be beneficial in weight management, there was no significant difference in terms of prevalence of metabolic syndrome and CVD risk score in gluten-free followers without CD.

Association of vegetarian diet with inflammatory biomarkers: a systematic review and meta-analysis of observational studies

OBJECTIVE

Vegetarian diets contain various anti-inflammatory components. We aimed to investigate the effects of vegetarianism on inflammatory biomarkers when compared with omnivores.

DESIGN

Systematic review and meta-analysis.

SETTING

Literature search was conducted in Science Direct, Proquest, MEDLINE and Google Scholar up to June 2016. Summary estimates and corresponding 95 % CI were derived via the DerSimonian and Laird method using random effects, subgroup analyses were run to find the source of heterogeneity and a fixed-effect model examined between-subgroup heterogeneity.

SUBJECTS

Studies were included if they evaluated effects of any type of vegetarianism compared with omnivores on circulating levels of inflammatory biomarkers. No restriction was made in terms of language or the date of study publications.

RESULTS

Eighteen articles were included. Pooled effect size showed no difference in high-sensitivity C-reactive protein (hs-CRP) levels in vegetarians v. omnivores (Hedges' g=-0·15; 95 % CI -0·35, 0·05), with high heterogeneity (I 2=75·6 %, P<0·01). A subgroup analysis by minimum duration of vegetarianism showed that a minimum duration of 2 years vegetarianism was associated with lower hs-CRP levels v. omnivores (Hedges' g=-0·29; 95 % CI -0·59, 0·01), with moderate heterogeneity (I 2=68·9 %, P<0·01). No significant effect was found in studies using a minimum duration of 6 months of vegetarianism, with low heterogeneity. Vegetarianism was associated with increased IL-6 concentrations (0·21 pg/ml; 95 % CI 0·18, 0·25), with no heterogeneity (I 2=0·0 %, P=0·60).

CONCLUSIONS

The meta-analysis provides evidence that vegetarianism is associated with lower serum concentrations of hs-CRP when individuals follow a vegetarian diet for at least 2 years. Further research is necessary to draw appropriate conclusions regarding potential associations between vegetarianism and IL-6 levels. A vegetarian diet might be a useful approach to manage inflammaging in the long term.

Two Physical Activity Measures: Paffenbarger Physical Activity Questionnaire Versus Aerobics Center Longitudinal Study as Predictors of Adult-Onset Type 2 Diabetes in a Follow-Up Study

PURPOSE

To compare 2 self-report methods of measuring weekly minutes of physical activity based on the Aerobics Center Longitudinal Study (ACLS) questionnaire and question 6 of the Paffenbarger Physical Activity Questionnaire (PPAQ) to determine the better predictor of adult-onset type 2 diabetes mellitus (T2DM).

DESIGN

An observational, prospective study.

SETTING

Survey data from the Adventist Health Study-2 (AHS-2) collected between 2002 and 2006 (baseline) and the Psychosocial Manifestations of Religion Sub-Study (PsyMRS), an AHS-2 subset collected 1 to 4 years later.

PATIENTS

Nine thousand eight hundred seventy-three male and female participants aged 23 to 106 years (mean, 63 years). Three hundred eighty participants reported adult-onset T2DM at follow-up.

MEASURES

Question 6 from the PPAQ and a question adopted from the ACLS were assessed at baseline. Incident diabetes was defined as participants who reported receiving treatment for adult-onset T2DM in the last 12 months in the PsyMRS and not at baseline.

ANALYSIS

Multivariate logistic regression analyses controlled for age, gender, ethnicity, education, body mass index (BMI), diet, and sedentary activity. Each exposure variable was compared to nonexercisers.

RESULTS

The PPAQ (odds ratio [OR]: 0.998; 95% confidence interval [CI]: 0.997-1.000) and the ACLS (OR: 0.999; 95% CI: 0.998-1.001) exhibited similar likelihood of predicting incident adult-onset T2DM in a healthy, mixed-gender population when controlling for several confounders.

CONCLUSIONS

The demonstrative nomenclature of the PPAQ may be more effectual in capturing physically active individuals than the ACLS notwithstanding generalizability and response bias limitations.

Cardio-Metabolic Benefits of Plant-Based Diets

Cardio-metabolic disease, namely ischemic heart disease, stroke, obesity, and type 2 diabetes, represent substantial health and economic burdens. Almost one half of cardio-metabolic deaths in the U.S. might be prevented through proper nutrition. Plant-based (vegetarian and vegan) diets are an effective strategy for improving nutrient intake. At the same time, they are associated with decreased all-cause mortality and decreased risk of obesity, type 2 diabetes, and coronary heart disease. Evidence suggests that plant-based diets may reduce the risk of coronary heart disease events by an estimated 40% and the risk of cerebral vascular disease events by 29%. These diets also reduce the risk of developing metabolic syndrome and type 2 diabetes by about one half. Properly planned vegetarian diets are healthful, effective for weight and glycemic control, and provide metabolic and cardiovascular benefits, including reversing atherosclerosis and decreasing blood lipids and blood pressure. The use of plant-based diets as a means of prevention and treatment of cardio-metabolic disease should be promoted through dietary guidelines and recommendations.

Dietary patterns and the risk of obesity, type 2 diabetes mellitus, cardiovascular diseases, asthma, and neurodegenerative diseases

Diet and lifestyle play a significant role in the development chronic diseases; however the full complexity of this relationship is not yet understood. Dietary pattern investigation, which reflects the complexity of dietary intake, has emerged as an alternative and complementary approach for examining the association between diet and chronic diseases. Literature on this association has largely focused on individual nutrients, with conflicting outcomes, but individuals consume a combination of foods from many groups that form dietary patterns. Our objective was to systematically review the current findings on the effects of dietary patterns on chronic diseases. In this review, we describe and discuss the relationships between dietary patterns, such as the Mediterranean, the Dietary Approach to Stop Hypertension, Prudent, Seventh-day Adventists, and Western, with risk of obesity, type-2 diabetes mellitus, cardiovascular diseases, asthma, and neurodegenearive diseases. Evidence is increasing from both observational and clinical studies that plant-based dietary patterns, which are rich in fruits, vegetables, and whole grains, are valuable in preventing various chronic diseases, whereas a diet high in red and processed meat, refined grains and added sugar seems to increase said risk. Dietary pattern analysis might be especially valuable to the development and evaluation of food-based dietary guidelines.

Position of the Academy of Nutrition and Dietetics: Vegetarian Diets

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage. Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease. Vegans need reliable sources of vitamin B-12, such as fortified foods or supplements.

Adherence to a Vegetarian Diet and Diabetes Risk: A Systematic Review and Meta-Analysis of Observational Studies

We quantitatively assessed the association between a vegetarian diet and diabetes risk using pooled estimates from observational studies. Electronic database searches for articles published from January 1980 to May 2016 were independently performed by two investigators, and 13 articles (14 studies) were identified. The pooled odds ratio (OR) for diabetes in vegetarians vs. non-vegetarians was 0.726 (95% confidence interval (CI): 0.608, 0.867). In the subgroup analyses, this inverse association was stronger for the studies conducted in the Western Pacific region (OR 0.514, 95% CI: 0.304, 0.871) and Europe/North America (OR 0.756, 95% CI: 0.589, 0.971) than studies conducted in Southeast Asia (OR 0.888, 95% CI: 0.718, 1.099). No study had a substantial effect on the pooled effect size in the influence analysis, and the Egger's (p = 0.465) and Begg's tests (p = 0.584) revealed no publication bias. This meta-analysis indicates that a vegetarian diet is inversely associated with diabetes risk. Our results support the need for further investigations into the effects of the motivations for vegetarianism, the duration of the adherence to a vegetarian diet, and type of vegetarian on diabetes risk.

Association between Dietary Energy Density and Incident Type 2 Diabetes in the Women's Health Initiative

BACKGROUND

Dietary energy density, or energy available in relation to gram intake, can inform disease risk.

OBJECTIVE

The objective of this study was to investigate the association between baseline dietary energy density and risk of incident type 2 diabetes in postmenopausal women.

DESIGN

Dietary energy density, weight status, and type 2 diabetes incidence were prospectively characterized in a large cohort of postmenopausal women participating in one or more clinical trials or an observational study.

PARTICIPANTS/SETTING

The study involved 161,808 postmenopausal women recruited to the Women's Health Initiative observational study or clinical trials at 40 centers across the United States between 1993 and 1998.

MAIN OUTCOME MEASURES

The primary outcome was incident type 2 diabetes.

STATISTICAL ANALYSES PERFORMED

The association between dietary energy density quintiles and incident diabetes was tested using Cox proportional hazards regression.

RESULTS

A total of 143,204 participants without self-reported diabetes at enrollment completed baseline dietary assessment and were followed for 12.7±4.6 years. Risk of diabetes developing was 24% greater for women in the highest dietary energy density quintile compared with the lowest after adjusting for confounders (95% CI 1.17 to 1.32). Body mass index (calculated as kg/m2) and waist circumference mediated the relationship between dietary energy density and diabetes. In waist circumference-stratified analysis, women in dietary energy density quintiles 2 to 5 with waist circumferences >88 cm were at 9% to 12% greater risk of diabetes developing compared with women with waist circumference ≤88 cm.

CONCLUSIONS

In this prospective study, a higher baseline dietary energy density was associated with higher incidence of type 2 diabetes among postmenopausal women, both overall, and in women with elevated waist circumference.

Vegetarian Diets in the Prevention and Management of Diabetes and Its Complications

IN BRIEF Epidemiological studies have found a lower prevalence of type 2 diabetes among vegetarians compared to nonvegetarians. This reduced risk is likely a function of improved weight status, higher intake of dietary fiber, and the absence of animal protein and heme iron in the diet. Interventional studies have shown that vegetarian diets, especially a vegan diet, are effective tools in glycemic control and that these diets control plasma glucose to a greater level than do control diets, including diets traditionally recommended for patients with diabetes (e.g., diets based on carbohydrate counting). Vegetarian diets are associated with improvement in secondary outcomes such as weight reduction, serum lipid profile, and blood pressure. Studies indicate that vegetarian diets can be universally used in type 2 diabetes prevention and as tools to improve blood glucose management.

Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies

The aim of this systematic review and meta-analysis was to synthesize the knowledge about the relation between intake of 12 major food groups and risk of type 2 diabetes (T2D). We conducted a systematic search in PubMed, Embase, Medline (Ovid), Cochrane Central, and Google Scholar for prospective studies investigating the association between whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSB) on risk of T2D. Summary relative risks were estimated using a random effects model by contrasting categories, and for linear and non-linear dose–response relationships. Six out of the 12 food-groups showed a significant relation with risk of T2D, three of them a decrease of risk with increasing consumption (whole grains, fruits, and dairy), and three an increase of risk with increasing consumption (red meat, processed meat, and SSB) in the linear dose–response meta-analysis. There was evidence of a non-linear relationship between fruits, vegetables, processed meat, whole grains, and SSB and T2D risk. Optimal consumption of risk-decreasing foods resulted in a 42% reduction, and consumption of risk-increasing foods was associated with a threefold T2D risk, compared to non-consumption. The meta-evidence was graded “low” for legumes and nuts; “moderate” for refined grains, vegetables, fruit, eggs, dairy, and fish; and “high” for processed meat, red meat, whole grains, and SSB. Among the investigated food groups, selecting specific optimal intakes can lead to a considerable change in risk of T2D.

Animal-Protein Intake Is Associated with Insulin Resistance in Adventist Health Study 2 (AHS-2) Calibration Substudy Participants: A Cross-Sectional Analysis

Background: High intakes of total and animal protein are associated with the risk of type 2 diabetes (T2D). The influence of protein type on insulin resistance, a key precursor of T2D, has not been extensively studied. Objective: The aim of this study was to determine the associations between dietary total, animal, and plant protein intakes as well as the animal-to-plant protein (AP) intake ratio with insulin resistance in middle-aged and older adults. Methods: This was a cross-sectional analysis in 548 participants (mean ± SD age: 66.2 ± 13.7 y) from the calibration substudy of the AHS-2 (Adventist Health Study 2) cohort. Participants consumed diets with a low AP intake ratio. Dietary intakes of total and particular types of protein were calculated from six 24-h dietary recalls. Participants completed a self-administered questionnaire on demographic, lifestyle, health, diet intake, and physical activity characteristics. Anthropometric variables including weight, height, and waist circumference were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated by using fasting serum glucose and insulin. Multiple linear regression models were used to test the relations between total and specific protein intakes with insulin resistance. Results: The ranges of dietary intakes of animal and plant protein and the AP intake ratio were 0.4-87.4 and 14.0-79.2 g/d and 0.02-4.43, respectively. Dietary intakes per 10-g/d increments of total protein (β: 0.11; 95% CI: 0.02, 0.21) and animal protein (β: 0.11; 95% CI: 0.01, 0.20) and the AP intake ratio (β: 1.82; 95% CI: 0.80, 2.84) were positively related to HOMA-IR. Plant protein was not significantly related to insulin resistance. Conclusion: Total and animal protein intakes and the AP intake ratio were positively associated with HOMA-IR in adults with relatively a low intake of animal protein and a high consumption of plant protein.

Vegetarian diet and all-cause mortality: Evidence from a large population-based Australian cohort - the 45 and Up Study

The vegetarian diet is thought to have health benefits including reductions in type 2 diabetes, hypertension, and obesity. Evidence to date suggests that vegetarians tend to have lower mortality rates when compared with non-vegetarians, but most studies are not population-based and other healthy lifestyle factors may have confounded apparent protective effects. The aim of this study was to evaluate the association between categories of vegetarian diet (including complete, semi and pesco-vegetarian) and all-cause mortality in a large population-based Australian cohort. The 45 and Up Study is a cohort study of 267,180 men and women aged ≥45years in New South Wales (NSW), Australia. Vegetarian diet status was assessed by baseline questionnaire and participants were categorized into complete vegetarians, semi-vegetarians (eat meat≤once/week), pesco-vegetarians and regular meat eaters. All-cause mortality was determined by linked registry data to mid-2014. Cox proportional hazards models quantified the association between vegetarian diet and all-cause mortality adjusting for a range of potential confounding factors. Among 243,096 participants (mean age: 62.3years, 46.7% men) there were 16,836 deaths over a mean 6.1years of follow-up. Following extensive adjustment for potential confounding factors there was no significant difference in all-cause mortality for vegetarians versus non-vegetarians [HR=1.16 (95% CI 0.93-1.45)]. There was also no significant difference in mortality risk between pesco-vegetarians [HR=0.79 (95% CI 0.59-1.06)] or semi-vegetarians [HR=1.12 (95% CI 0.96-1.31)] versus regular meat eaters. We found no evidence that following a vegetarian diet, semi-vegetarian diet or a pesco-vegetarian diet has an independent protective effect on all-cause mortality.

Variations in dietary intake and plasma concentrations of plant sterols across plant-based diets among North American adults

SCOPE

Phytosterols are bioactive compounds in plants with similar cholesterol-lowering properties as vegetarian diets. However, information on phytosterol intake and plasma plant sterols among vegetarians is sparse.

METHODS AND RESULTS

We examined dietary intake and plasma concentration of plant sterols and cholesterol across five dietary patterns in the Adventist Health Study-2 Calibration Sub-study (n = 861, 66% females, average age 61 years). To measure intake and plasma concentrations of these compounds, we used 24-h dietary recalls and gas-liquid chromatography-flame ionization detection, respectively. Mean (SD) total phytosterol and cholesterol intake were 363 (176) mg/day and 131 (111) mg/day; plasma β-sitosterol, campesterol, and cholesterol were 3.3 (1.7) μg/mL, 4.2 (2.3) μg/mL, and 1.9 (0.4) mg/mL, respectively. Total phytosterol intake was lowest among non-vegetarians (263 mg/day) and highest among vegans (428 mg/day) (p < 0.0001). Cholesterol intake was lowest among vegans (15.2 mg/day) and highest among non-vegetarians (124.6 mg/day) (p < 0.0001). Plasma plant sterols and cholesterol did not differ by diet. Cholesterol-adjusted plasma β-sitosterol and campesterol were significantly higher in Blacks than Whites, though no ethnic differences were observed in dietary intake of these plant sterols.

CONCLUSION

Dietary intake but not plasma concentration of plant sterols and cholesterol varies across distinct plant-based diets.

Self-Report Dietary Assessment Tools Used in Canadian Research: A Scoping Review

Choosing the most appropriate dietary assessment tool for a study can be a challenge. Through a scoping review, we characterized self-report tools used to assess diet in Canada to identify patterns in tool use and to inform strategies to strengthen nutrition research. The research databases Medline, PubMed, PsycINFO, and CINAHL were used to identify Canadian studies published from 2009 to 2014 that included a self-report assessment of dietary intake. The search elicited 2358 records that were screened to identify those that reported on self-report dietary intake among nonclinical, non-Aboriginal adult populations. A pool of 189 articles (reflecting 92 studies) was examined in-depth to assess the dietary assessment tools used. Food-frequency questionnaires (FFQs) and screeners were used in 64% of studies, whereas food records and 24-h recalls were used in 18% and 14% of studies, respectively. Three studies (3%) used a single question to assess diet, and for 3 studies the tool used was not clear. A variety of distinct FFQs and screeners, including those developed and/or adapted for use in Canada and those developed elsewhere, were used. Some tools were reported to have been evaluated previously in terms of validity or reliability, but details of psychometric testing were often lacking. Energy and fat were the most commonly studied, reported by 42% and 39% of studies, respectively. For ∼20% of studies, dietary data were used to assess dietary quality or patterns, whereas close to half assessed ≤5 dietary components. A variety of dietary assessment tools are used in Canadian research. Strategies to improve the application of current evidence on best practices in dietary assessment have the potential to support a stronger and more cohesive literature on diet and health. Such strategies could benefit from national and global collaboration.

Flexitarian Diets and Health: A Review of the Evidence-Based Literature

A flexitarian or semi-vegetarian diet (SVD) is one that is primarily vegetarian with the occasional inclusion of meat or fish. Of late, there appears to be an increasing movement toward this practice. There has not been a recent update on these diets from a health perspective. Using the National Centre for Biotechnology Information PubMed database, a search was made for all studies published between 2000 and 2016 that met defined inclusion criteria. A total of 25 studies were located with 12 focusing on body weight and diet quality. There was emerging evidence suggestive of benefits for body weight, improved markers of metabolic health, blood pressure, and reduced risk of type 2 diabetes. SVD may also have a role to play in the treatment of inflammatory bowel diseases, such as Crohn’s disease. Given that there is a higher tendency for females to be flexitarian yet males are more likely to overconsume meat, there is a clear need to communicate the potential health benefits of these diets to males.

Red Meat and Health

Despite its nutritional benefits, there is an increasing body of evidence to suggest that regular consumption of red meat may negatively impact health and disease risk, including the risk of most common chronic diseases. This chapter reviews the current evidence linking red and processed meat intakes with chronic disease, obesity and mortality risks and discusses possible mechanisms to explain these associations. Research on the health benefits of diets low in red meat, including vegetarian, vegan, Mediterranean and other plant-based diets, is also reviewed.

Worse inflammatory profile in omnivores than in vegetarians associates with the gut microbiota composition

AIMS

To describe the abundance of major phyla and some genera in the gut microbiota of individuals according to dietary habits and examine their associations with inflammatory markers, insulin resistance, and cardiovascular risk profile.

METHODS

A total of 268 non-diabetic individuals were stratified into groups of dietary types (strict vegetarians, lacto-ovo-vegetarians, and omnivores). The taxonomic composition and phylogenetic structure of the microbiota were obtained through the analysis of the 16S rRNA gene. Samples were clustered into operational taxonomic units at 97% similarity using GreenGenes 13.5 database. Clinical, biochemical, and circulating inflammatory markers were compared by ANOVA or Kruskal-Wallis test.

RESULTS

The sample (54.2% women, mean age 49.5 years) was composed of 66 strict vegetarians, 102 lacto-ovo-vegetarians and 100 omnivores. Considering the entire sample, the greatest abundant phyla were Firmicutes (40.7 ± 15.9%) and Bacteroidetes (39.5 ± 19.9%), and no difference in abundances was found between individuals with normal and excess weight. Stratifying by dietary types, the proportion of Firmicutes was lower and of Bacteroidetes was higher in strict vegetarians when compared to lacto-ovo-vegetarians and omnivores. At the genus level, strict vegetarians had a higher Prevotella abundance and Prevotella/Bacteroides ratio than the other groups. They also had a lower proportion of Faecalibacterium than lacto-ovo-vegetarians, and both vegetarian groups had higher proportions than did omnivores. Succinivibrio and Halomonas from the Proteobacteria phylum were overrepresented in omnivores. The omnivorous group showed higher values of anthropometric data, insulin, HOMA-IR, and a worse lipid profile. Inflammatory markers exhibited a gradual and significant increase from the vegetarians and lacto-ovo-vegetarians to the omnivorous group.

CONCLUSIONS

There are differences in gut microbiota composition of individuals with distinct dietary habits, who differ according to their inflammatory and metabolic profiles. Based on the findings relative to bacteria abundances and on their recognized actions in the metabolism, we suggest that exposure to animal foods may favor an intestinal environment which could trigger systemic inflammation and insulin resistance-dependent metabolic disorders.

Linking dietary patterns with gut microbial composition and function

Emerging insights have implicated the gut microbiota as an important factor in the maintenance of human health. Although nutrition research has focused on how direct interactions between dietary components and host systems influence human health, it is becoming increasingly important to consider nutrient effects on the gut microbiome for a more complete picture. Understanding nutrient-host-microbiome interactions promises to reveal novel mechanisms of disease etiology and progression, offers new disease prevention strategies and therapeutic possibilities, and may mandate alternative criteria to evaluate the safety of food ingredients. Here we review the current literature on diet effects on the microbiome and the generation of microbial metabolites of dietary constituents that may influence human health. We conclude with a discussion of the relevance of these studies to nutrition and public health and summarize further research needs required to realize the potential of exploiting diet-microbiota interactions for improved health.

Sugar and Type 2 diabetes

BACKGROUND

Consumption of sugar, specifically sugar-sweetened beverages, has been widely held responsible by the media for the global rise in Type 2 diabetes (T2DM).

SOURCES OF DATA

Systematic reviews and dietary guidelines relating dietary sugars to T2DM.

AREAS OF AGREEMENT

Weight gain and T2DM incidence are associated with diet and lifestyle patterns characterized by high consumptions of any sweetened beverages. High sugar intakes impair risk factors for macrovascular complications of T2DM.

AREAS OF CONTROVERSY

Much of the association between sugars and T2DM is eliminated by adjusting data for body mass index (BMI). However, BMI adjustment does not fully account for adiposity (r²=0.65-0.75). Excess sugar can promote weight gain, thus T2DM, through extra calories, but has no unique diabetogenic effect at physiological levels.

GROWING POINTS

Ethical concerns about caffeine added to sweetened beverages, undetectable by consumers, to increase consumption.

AREAS TIMELY FOR DEVELOPING RESEARCH

Evidence needed for limiting dietary sugar below 10% energy intake.

The long-term health of vegetarians and vegans

Vegetarians, who do not eat any meat, poultry or fish, constitute a significant minority of the world's population. Lacto-ovo-vegetarians consume dairy products and/or eggs, whereas vegans do not eat any foods derived wholly or partly from animals. Concerns over the health, environmental and economic consequences of a diet rich in meat and other animal products have focussed attention on those who exclude some or all of these foods from their diet. There has been extensive research into the nutritional adequacy of vegetarian diets, but less is known about the long-term health of vegetarians and vegans. We summarise the main findings from large cross-sectional and prospective cohort studies in western countries with a high proportion of vegetarian participants. Vegetarians have a lower prevalence of overweight and obesity and a lower risk of IHD compared with non-vegetarians from a similar background, whereas the data are equivocal for stroke. For cancer, there is some evidence that the risk for all cancer sites combined is slightly lower in vegetarians than in non-vegetarians, but findings for individual cancer sites are inconclusive. Vegetarians have also been found to have lower risks for diabetes, diverticular disease and eye cataract. Overall mortality is similar for vegetarians and comparable non-vegetarians, but vegetarian groups compare favourably with the general population. The long-term health of vegetarians appears to be generally good, and for some diseases and medical conditions it may be better than that of comparable omnivores. Much more research is needed, particularly on the long-term health of vegans.

A Comprehensive Review of the Literature Supporting Recommendations From the Canadian Diabetes Association for the Use of a Plant-Based Diet for Management of Type 2 Diabetes

Type 2 diabetes mellitus is considered one of the fastest growing diseases in Canada, representing a serious public health concern. Thus, clinicians have begun targeting modifiable risk factors to manage type 2 diabetes, including dietary patterns such as a plant-based diets (PBDs). The Canadian Diabetes Association has included PBDs among the recommended dietary patterns to be used in medical nutrition therapy for persons with type 2 diabetes. To support knowledge translation, this review summarizes the current literature relating to PBDs and the prevalence of type 2 diabetes, its clinical applications and its acceptability in the management of type 2 diabetes as well as its application in community settings. This comprehensive review seeks to close the literature gap by providing background and rationale to support the use of PBDs as medical nutrition therapy. Within this review is support from large observational studies, which have shown that PBDs were associated with lower prevalence of type 2 diabetes. As well, intervention studies have shown that PBDs were just as effective, if not more effective, than other diabetes diets in improving body weight, cardiovascular risk factors, insulin sensitivity, glycated hemoglobin levels, oxidative stress markers and renovascular markers. Furthermore, patient acceptability was comparable to other diabetes diets, and PBDs reduced the need for diabetes medications. Diabetes education centres in Canada could improve patients' perceptions of PBDs by developing PBD-focused education and support as well as providing individualized counselling sessions addressing barriers to change. The development of more standardized and user-friendly PBD practice guidelines could overcome the disparity in recommendations and, thereby, increase how frequently practitioners recommend PBDs. Based on current published research, PBDs lend support in the management of type 2 diabetes.

Plant-Based Dietary Patterns and Incidence of Type 2 Diabetes in US Men and Women: Results from Three Prospective Cohort Studies

BACKGROUND

Plant-based diets have been recommended to reduce the risk of type 2 diabetes (T2D). However, not all plant foods are necessarily beneficial. We examined the association of an overall plant-based diet and hypothesized healthful and unhealthful versions of a plant-based diet with T2D incidence in three prospective cohort studies in the US.

METHODS AND FINDINGS

We included 69,949 women from the Nurses' Health Study (1984-2012), 90,239 women from the Nurses' Health Study 2 (1991-2011), and 40,539 men from the Health Professionals Follow-Up Study (1986-2010), free of chronic diseases at baseline. Dietary data were collected every 2-4 y using a semi-quantitative food frequency questionnaire. Using these data, we created an overall plant-based diet index (PDI), where plant foods received positive scores, while animal foods (animal fats, dairy, eggs, fish/seafood, poultry/red meat, miscellaneous animal-based foods) received reverse scores. We also created a healthful plant-based diet index (hPDI), where healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, vegetable oils, tea/coffee) received positive scores, while less healthy plant foods (fruit juices, sweetened beverages, refined grains, potatoes, sweets/desserts) and animal foods received reverse scores. Lastly, we created an unhealthful plant-based diet index (uPDI) by assigning positive scores to less healthy plant foods and reverse scores to healthy plant foods and animal foods. We documented 16,162 incident T2D cases during 4,102,369 person-years of follow-up. In pooled multivariable-adjusted analysis, both PDI and hPDI were inversely associated with T2D (PDI: hazard ratio [HR] for extreme deciles 0.51, 95% CI 0.47-0.55, p trend < 0.001; hPDI: HR for extreme deciles 0.55, 95% CI 0.51-0.59, p trend < 0.001). The association of T2D with PDI was considerably attenuated when we additionally adjusted for body mass index (BMI) categories (HR 0.80, 95% CI 0.74-0.87, p trend < 0.001), while that with hPDI remained largely unchanged (HR 0.66, 95% CI 0.61-0.72, p trend < 0.001). uPDI was positively associated with T2D even after BMI adjustment (HR for extreme deciles 1.16, 95% CI 1.08-1.25, p trend < 0.001). Limitations of the study include self-reported diet assessment, with the possibility of measurement error, and the potential for residual or unmeasured confounding given the observational nature of the study design.

CONCLUSIONS

Our study suggests that plant-based diets, especially when rich in high-quality plant foods, are associated with substantially lower risk of developing T2D. This supports current recommendations to shift to diets rich in healthy plant foods, with lower intake of less healthy plant and animal foods.

Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study

Background

Beneficial and detrimental effects of various vegetarian and vegan diets on the health status are well known. Considering the growing background numbers of vegetarians and vegans, the number of vegetarian and vegan runners is likely to rise, too. Therefore, the Nutrition and Running High Mileage (NURMI) Study was designed as a comparative study to investigate the prevalence of omnivores, vegetarians, and vegans in running events and to detect potential differences in running performance comparing these three subgroups.

Methods/design

The NURMI Study will be conducted in three steps following a cross-sectional design. Step 1 will determine epidemiological aspects of endurance runners (any distance) using a short standardized questionnaire. Step 2 will investigate dietary habits and running history from eligible participants (capable of running a half-marathon at least) using an extended standardized questionnaire. Step 3 will collect data after a running event on finishing time and final ranking as well as a post-race rating of perceived exertion, mood status, nutrient and fluid intake during the race.

Discussion

Our study will provide a major contribution to overcome the lack of data on the prevalence and running performance of vegetarian and vegan runners in endurance running events. We estimate the prevalence of vegetarians and vegans participating in a running event to be less compared to the respective proportion of vegetarians and vegans to the general population. Furthermore we will validate the subject’s self-assessment of their respective diet. This comparative study may identify possible effects of dietary behavior on running performance und may detect possible differences between the respective subgroups: omnivorous, vegetarian and vegan runners.

Trial registration Current controlled trials, ISRCTN73074080

Atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.

The moderate essential amino acid restriction entailed by low-protein vegan diets may promote vascular health by stimulating FGF21 secretion

The serum total and LDL cholesterol levels of long-term vegans tend to be very low. The characteristically low ratio of saturated to unsaturated fat in vegan diets, and the absence of cholesterol in such diets, clearly contribute to this effect. But there is reason to suspect that the quantity and composition of dietary protein also play a role in this regard. Vegan diets of moderate protein intake tend to be relatively low in certain essential amino acids, and as a result may increase hepatic activity of the kinase GCN2, which functions as a gauge of amino acid status. GCN2 activation boosts the liver's production of fibroblast growth factor 21 (FGF21), a factor which favorably affects serum lipids and metabolic syndrome. The ability of FGF21 to decrease LDL cholesterol has now been traced to at least two mechanisms: a suppression of hepatocyte expression of sterol response element-binding protein-2 (SREBP-2), which in turn leads to a reduction in cholesterol synthesis; and up-regulated expression of hepatocyte LDL receptors, reflecting inhibition of a mechanism that promotes proteasomal degradation of these receptors. In mice, the vascular benefits of FGF21 are also mediated by favorable effects on adipocyte function - most notably, increased adipocyte secretion of adiponectin, which directly exerts anti-inflammatory effects on the vasculature which complement the concurrent reduction in LDL particles in preventing or reversing atherosclerosis. If, as has been proposed, plant proteins preferentially stimulate glucagon secretion owing to their amino acid composition, this would represent an additional mechanism whereby plant protein promotes FGF21 activity, as glucagon acts on the liver to boost transcription of the FGF21 gene.

Red Meat and Health

Despite its nutritional benefits, there is an increasing body of evidence to suggest that regular consumption of red meat may negatively impact health and disease risk, including the risk of most common chronic diseases. This chapter reviews the current evidence linking red and processed meat intakes with chronic disease, obesity and mortality risks and discusses possible mechanisms to explain these associations. Research on the health benefits of diets low in red meat, including vegetarian, vegan, Mediterranean and other plant-based diets, is also reviewed.

Novel Risk Factors for Type 2 Diabetes in African-Americans

In the USA, compared to whites, African-Americans are disproportionately impacted by the diabetes epidemic. Traditional diabetes risk factors, such as obesity, are more common among African-Americans, but these traditional risk factors do not explain all of the disparity in diabetes risk. Recent research has identified novel environmental, lifestyle, physiologic, and genetic risk factors for diabetes, some of which appear to impact African-Americans more than whites. This manuscript reviews the recent literature to highlight some of these novel risk factors that may be contributing to the racial disparity in diabetes risk. Further study is needed of the modifiable risk factors for development of interventions to reduce the risk of diabetes in African-Americans, as well as other high-risk populations.

Effect of Replacing Animal Protein with Plant Protein on Glycemic Control in Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Previous research on the effect of replacing sources of animal protein with plant protein on glycemic control has been inconsistent. We therefore conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of this replacement on glycemic control in individuals with diabetes. We searched MEDLINE, EMBASE, and Cochrane databases through 26 August 2015. We included RCTs ≥ 3-weeks comparing the effect of replacing animal with plant protein on HbA1c, fasting glucose (FG), and fasting insulin (FI). Two independent reviewers extracted relevant data, assessed study quality and risk of bias. Data were pooled by the generic inverse variance method and expressed as mean differences (MD) with 95% confidence intervals (CIs). Heterogeneity was assessed (Cochran Q-statistic) and quantified (I²-statistic). Thirteen RCTs (n = 280) met the eligibility criteria. Diets emphasizing a replacement of animal with plant protein at a median level of ~35% of total protein per day significantly lowered HbA1c (MD = -0.15%; 95%-CI: -0.26, -0.05%), FG (MD = -0.53 mmol/L; 95%-CI: -0.92, -0.13 mmol/L) and FI (MD = -10.09 pmol/L; 95%-CI: -17.31, -2.86 pmol/L) compared with control arms. Overall, the results indicate that replacing sources of animal with plant protein leads to modest improvements in glycemic control in individuals with diabetes. Owing to uncertainties in our analyses there is a need for larger, longer, higher quality trials.

TRIAL REGISTRATION

ClinicalTrials.gov registration number: NCT02037321.

The Mediterranean Lifestyle as a Non-Pharmacological and Natural Antioxidant for Healthy Aging

Oxidative stress has been suggested to affect age-associated physiological dysfunction. Therefore, it is speculated that antioxidant supplements could have a potential role in preventing age-related diseases and death. Among different dietary habits, the highly antioxidant Mediterranean dietary pattern, which includes high vegetable and fruit intake, consumption of legumes, cereals, and fish, low intake of meat and dairy derivatives, moderate red wine consumption, and use of extra-virgin olive oil, is characterized by other aspects than food, such as conviviality, sensory stimulation, socialization, biodiversity, and seasonality that can reinforce the Mediterranean diet’s (MeD) beneficial effects on wellbeing, quality of life, and healthy aging. The present review aims to discuss available data on the relationship between oxidative stress and aging, biomarkers of oxidative stress status, protective effects of the MeD, and the adoption of the Mediterranean lifestyle as a non-pharmacological and natural tool to cope with oxidative stress damage for a longer life span, and—even more important—healthy aging beyond the biological, psychological, and social challenges that old age entails.