Vegetarian diets and health

Update on Plant-Based Diets and Cardiometabolic Risk

PURPOSE OF REVIEW

The number of published studies on the health effects of plant-based diets has increased dramatically in the last decade. The purpose of this narrative review is to update the most recent evidence from large prospective cohort studies and meta-analyses on the effects of plant-based dietary patterns on cardiovascular outcomes and risk factors and total mortality.

RECENT FINDINGS

Most new data from large prospective cohort studies carried out in the USA, Europe, and Asia continue to show inverse associations between plant-based diets and the incidence of ischemic heart disease and stroke, while less data exist for heart failure incidence. New analyses suggest that only some components of plant-based diets are associated with cardiovascular benefit. Recent meta-analyses show inverse associations between plant-protein intake and all-cause mortality, although heterogeneity exists, and small mortality risks from some animal proteins, notably processed meats. New studies continue to demonstrate small but favorable effects of plant-based diets on traditional risk factors and suggest other emerging mechanisms by which plant-based diets exert cardiovascular benefits. The recommendation to consume a plant-based diet to reduce cardiovascular risk remains an evidence-based strategy based on observational studies. New data highlight the importance of ensuring that these diets are nutrient-rich and low in plant foods associated with signals of harm. For this reason, assessment of diet quality is important even in patients who report adherence to plant-based diets. Large randomized trials with hard cardiovascular endpoints might strengthen this evidence-base, but feasibility is limited.

The effect of milk and rapeseed protein on growth factors in 7-8 year-old healthy children - A randomized controlled trial

OBJECTIVE

Milk protein may stimulate linear growth through insulin-like growth factor-1 (IGF-1). However, the effect of plant proteins on growth factors is largely unknown. This study assesses the effect of combinations of milk and rapeseed protein versus milk protein alone on growth factors in children.

DESIGN

An exploratory 3-armed randomized, double-blind, controlled trial was conducted in 129 healthy 7-8 year-old Danish children. Children received 35 g milk and rapeseed protein (ratio 54:46 or 30:70) or 35 g milk protein per day for 4 weeks. The primary outcome was difference in IGF-1 changes between intervention groups after 4 weeks. Secondary outcomes included changes in IGF-1 after 1 week and changes in insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3, insulin, height, weight and body composition after 1 and 4 weeks. Results were analysed by multiple linear mixed-effect models.

RESULTS

There were no differences in changes of plasma IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3 ratio or insulin between groups after 1 or 4 weeks based on 89 complete cases (P > 0.10). IGF-1 increased by 13.7 (95% CI 9.7;17.7) ng/mL and 18.0 (14.0;22.0) ng/mL from baseline to week 1 and 4, respectively, a 16% increase during the intervention. Similarly, insulin increased by 31% (14; 50) and 33% (16; 53) from baseline to week 1 and 4. Fat-free mass index (FFMI) increments were higher with milk alone than rapeseed blends (P < 0.05), coinciding with a trend towards a lower height increment. Body mass index increased within all groups (P < 0.05), mainly due to an increase in FFMI (P < 0.01).

CONCLUSION

There were no differences in changes of growth factors between the combinations of milk and rapeseed protein and milk protein alone in healthy, well-nourished children with a habitual intake of milk. Within groups, growth factors increased considerably. Future studies are needed to investigate how intakes of plant and animal proteins affect childhood growth.

Vegetarian Diets, Ayurveda, and the Case for an Integrative Nutrition Science

Two recent studies of the health effects of vegetarian diets reported conflicting results: the EPIC-Oxford study reported a significant increase in strokes among vegetarians compared to meat-eaters among a predominantly Caucasian cohort, while another, performed on Taiwanese Buddhists, reported significantly lower incidence of strokes among vegetarians. This was doubly puzzling given the pronounced decrease in cardiovascular events among the EPIC-Oxford group. In this article, we make a detailed comparison of the actual dietary intake of various food groups by the cohorts in these studies. We then use the nutritional principles of Ayurveda—traditional Indian medicine—to show how these apparently contradictory results may be explained. Systems of traditional medicine such as Ayurveda possess profound knowledge of the effects of food on physiology. Ayurveda takes into account not just the type of food, but also multiple other factors such as taste, temperature, and time of consumption. Traditional cuisines have evolved hand in hand with such systems of medicine to optimize nutrition in the context of local climate and food availability. Harnessing the experiential wisdom of these traditional systems to create an integrative nutrition science would help fight the ongoing epidemic of chronic lifestyle diseases, and improve health and wellness.

The association between plant-based diet and erectile dysfunction in Chinese men

Background

Diet, one of the components of lifestyle, has been believed to have associations with erectile dysfunction (ED). However, whether there is an association between plant-based diet and ED is remains to be explored. Thus, we conducted the nested case-control study to investigate the relationship between the plant-based diet and ED in China.

Results

ED group (92 subjeczts) and ED free group (92 subjects) were similar in terms of basic features (P > 0.05), except for lifestyle (P < 0.05). The plant-diet index (PDI) and healthy plant-diet index (hPDI) in the ED group were significantly lower than those in the control group (P < 0.001). Adjusted multivariate analysis indicated that the presence of ED was negatively associated with nitric oxide levels, PDI, and hPDI (all P < 0.05), and was positively related to body mass index, metabolic syndrome, and E-selectin levels. Furthermore, both the PDI and hPDI increased significantly as the International Index of Erectile Function (IIEF-5) scores increased within the ED group (P < 0.05). Multi-model multivariate analysis indicated the robustness of results.

Conclusions

More plant-based diet intake was associated with a reduced presence of ED and less severe ED in China. Committing to plant-based diet can be encouraged for many health benefits and to lower ED burden. Further well-designed studies are warranted to validate our findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12610-021-00129-5.

The association between plant-based diet and erectile function in Chinese young healthy men: A population-based study

The study was designed and conducted to evaluate the plant-based diet status and its association with erectile function (EF) in Chinese young healthy men. From July 2018 to May 2020, 116 objectively proved physically and psychologically healthy men were selected. Clinical questionnaires, detailed physical examinations and blood tests were all assessed. An overall plant-based diet index (PDI) and a healthful plant-based diet index (hPDI) were developed from each participant to measure plant-based diet quantitatively. The EF was measured by both the International Index of Erectile Function-5 (IIEF-5) and the surrogated measures of endothelial function, peripheral levels of nitric oxide (NO) and E-selectin. In subjects, the mean PDI and hPDI were 53.8 ± 8.2 and 54.7 ± 8.9 respectively. Results of multivariate analysis showed that both PDI and hPDI were negatively associated with BMI (all p < .05), but had no relationships with NO, E-selectin, TT levels and IIEF-5 scores (all p > .05). In a subgroup of male population, Chinese young healthy men, the plant-based diet, measured by PDI and hPDI, was not related to erectile function. The population can adhere to plant-based diet to keep healthy without concerns of negative influence on erectile function.

Intake and adequacy of the vegan diet. A systematic review of the evidence

BACKGROUND

Vegan diets, where animal- and all their by-products are excluded from the diet, have gained popularity, especially in the last decade. However, the evaluation of this type of diet has not been well addressed in the scientific literature. This study aimed to investigate the adequacy of vegan diets in European populations and of their macro- and micronutrient intakes compared to World Health Organization recommendations.

METHODS

A systematic search in PubMed, Web of Science, IBSS, Cochrane library and Google Scholar was conducted and 48 studies (12 cohorts and 36 cross-sectional) were included.

RESULTS

Regarding macronutrients, vegan diets are lower in protein intake compared with all other diet types. Veganism is also associated with low intake of vitamins B₂, Niacin (B₃), B₁₂, D, iodine, zinc, calcium, potassium, selenium. Vitamin B₁₂ intake among vegans is significantly lower (0.24-0.49 μg, recommendations are 2.4 μg) and calcium intake in the majority of vegans was below recommendations (750 mg/d). No significant differences in fat intake were observed. Vegan diets are not related to deficiencies in vitamins A, B₁, Β₆, C, E, iron, phosphorus, magnesium, copper and folate and have a low glycemic load.

CONCLUSIONS

Following a vegan diet may result in deficiencies in micronutrients (vitamin B₁₂, zinc, calcium and selenium) which should not be disregarded. However, low micro- and macronutrient intakes are not always associated with health impairments. Individuals who consume a vegan diet should be aware of the risk of potential dietary deficiencies.