Background: The cardiovascular and other health benefits and potential harms of protein and micronutrient deficiency of vegetarian diets continue to be debated.
Methods: Study participants included urban migrants, their rural siblings and urban residents (n = 6555, mean age - 40.9 yrs) of the Indian Migration Study from Lucknow, Nagpur, Hyderabad and Bangalore. Information on diet (validated interviewer-administered semi-quantitative food frequency questionnaire), tobacco, alcohol, physical activity, medical histories, as well as blood pressure, fasting blood and anthropometric measurements were collected. Nutrient databases were used to calculate nutrient content of regional recipes. Vegetarians ate no eggs, fish, poultry and meat. Using multivariate linear regression with robust standard error model, we compared the macro- and micro-nutrient profile of vegetarian and non-vegetarian diets.
Results: Vegetarians, (32.8% of the population), consumed greater amounts of legumes, vegetables, roots and tubers, dairy and sugar, while non-vegetarians had a greater intake of cereals, fruits, spices, salt (p < 0.01), fats and oils. Vegetarians had a higher socioeconomic status, and were less likely to smoke, drink alcohol (p < 0.0001) and engage in less physical activity (p = 0.04). On multivariate analysis, vegetarians consumed more carbohydrates (β = 7.0 g/day (95% CI: 9.9 to 4.0), p < 0.0001), vitamin C (β = 8.7 mg/day (95% CI: 4.3 to13.0), p < 0.0001) and folate (β = 8.0 mcg/day (95% CI: 3.3 to 12.7), p = 0.001) and lower levels of fat (β = -1.6 g/day (95% CI: -0.62 to -2.7), p = 0.002), protein (β = -6.4 g/day (95% CI: -5.8 to -7.0), p < 0.0001), vitamin B12 (β = -1.4 mcg/day (95% CI: -1.2 to -1.5), p < 0.0001) and zinc (β = -0.6 mg/day (95% CI: -0.4 to -0.7), p < 0.0001).
Conclusion: Overall, Indian vegetarian diets were found to be adequate to sustain nutritional demands according to recommended dietary allowances with less fat. Lower vitamin B12 bio-availability remains a concern and requires exploration of acceptable dietary sources for vegetarians.