The influence of vegetarian nutrition on health: A systematic review

Aim: This study is a systematic review conducted to evaluate the effect of vegetarian nutrition on nutritional deficiencies, weight management, risk factors of metabolic syndrome and some diseases. Materials and methods: In this systematic review, declaration of the PRISMA (Preferred Reporting Items for Systematic review and MetaAnalysis) has been used as guidance. Literature search was done in PubMed and Google Scholar databases. Criteria for inclusion of the studies reviewed; randomized-controlled, experimental studies and access to the full text of the article. Results: Fifty-five research articles, 20 of which were randomized controlled, 13 of which were experimental and 22 of which were semi-experimental studies, were examined. Deficiency of vitamin B12, calcium, selenium and vitamin D is potential problems for vegetarians. Adequate and balanced vegetarian diet provides lower body weight and BMI than meat-eaters. Vegetarian diets can effectively lower TC, LDL-C, HDL-C and blood pressure. These findings have important public health effects for the management of dyslipidemia, particularly hypercholesterolemia and hypertension through dietary intervention. A vegetarian diet for health conscious individuals in Type 2 diabetes, cardiovascular disease and may provide benefits against cancer, but these results due to small sample sizes and few studies evaluating this aspect should be interpreted cautiously. Conclusion: For adequate defining of vegetarian diets and optimal health, further intervention is needed before broadly defended. Long-term, randomized controlled studies with large sample size should be conducted in our country for the effect of vegetarian nutrition on health. The findings of our systematic review may be a guide for further studies. Key Words: Deficiency, health, nurtients, vegan, vegetarian.