Legume consumption and its association with fasting glucose, insulin resistance and type 2 diabetes in the Indian Migration Study.

OBJECTIVE: Legume consumption is associated with lower fasting glucose (FG) and insulin levels in nutrition trials and lower CVD mortality in large-scale epidemiological studies. In India, legumes are widely consumed in various preparations, yet no epidemiological study has evaluated the association of legumes with FG levels, insulin resistance and diabetes risk. The present study aimed to fill this gap. DESIGN: Fasting blood samples, in-person interviews to obtain information on demographic/socio-economic factors, physical activity, alcohol and tobacco use, and anthropometric measurements were collected. Dietary intakes were assessed by an interviewer-administered, validated, semi-quantitative FFQ. SETTING: Lucknow, Nagpur, Hyderabad and Bangalore, India. SUBJECTS: Men and women (n 6367) aged 15-76 years - urban residents, urban migrants and their rural siblings. RESULTS: In multivariate random-effects models adjusted for age, BMI, total energy intake, macronutrients, physical activity and rural/migration status, daily legume consumption was not associated with FG (P-for-trend=0·78), insulin resistance (homeostasis model assessment score; P-for-trend=0·73) or the prevalence of type 2 diabetes mellitus (P-for-trend=0·41). Stratified analyses by vegetarian diet and migration status did not change the findings. Inverse associations between legumes and FG emerged for participants with lower BMI and higher carbohydrate, protein, fat and sugar intakes. CONCLUSIONS: Although legumes are essential in traditional Indian diets, as well as in prudent and Mediterranean diets in the West, we did not find an association between legumes and markers of glycaemic control, insulin resistance or diabetes, except for subgroups based on BMI and macronutrient intake. The ubiquitous presence and complexity of legume preparations in Indian diets may contribute to these findings.

The association between a vegetarian diet and cardiovascular disease (CVD) risk factors in India: the Indian Migration Study.

BACKGROUND: Studies in the West have shown lower cardiovascular disease (CVD) risk among people taking a vegetarian diet, but these findings may be confounded and only a minority selects these diets. We evaluated the association between vegetarian diets (chosen by 35%) and CVD risk factors across four regions of India. METHODS: Study participants included urban migrants, their rural siblings and urban residents, of the Indian Migration Study from Lucknow, Nagpur, Hyderabad and Bangalore (n = 6555, mean age-40.9 yrs). Information on diet (validated interviewer-administered semi-quantitative food frequency questionnaire), tobacco, alcohol, physical history, medical history, as well as blood pressure, fasting blood and anthropometric measurements were collected. Vegetarians ate no eggs, fish, poultry or meat. Using robust standard error multivariate linear regression models, we investigated the association of vegetarian diets with blood cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides, fasting blood glucose (FBG), systolic (SBP) and diastolic blood pressure (DBP). RESULTS: Vegetarians (32.8% of the study population) did not differ from non-vegetarians with respect to age, use of smokeless tobacco, body mass index, and prevalence of diabetes or hypertension. Vegetarians had a higher standard of living and were less likely to smoke, drink alcohol (p<0.0001) and were less physically active (p = 0.04). In multivariate analysis, vegetarians had lower levels of total cholesterol (ß =  -0.1 mmol/L (95% CI: -0.03 to -0.2), p = 0.006), triglycerides (ß =  -0.05 mmol/L (95% CI: -0.007 to -0.01), p = 0.02), LDL (ß =  -0.06 mmol/L (95% CI: -0.005 to -0.1), p = 0.03) and lower DBP (ß =  -0.7 mmHg (95% CI: -1.2 to -0.07), p = 0.02). Vegetarians also had decreases in SBP (ß =  -0.9 mmHg (95% CI: -1.9 to 0.08), p = 0.07) and FBG level (ß =  -0.07 mmol/L (95% CI: -0.2 to 0.01), p = 0.09) when compared to non-vegetarians. CONCLUSION: We found beneficial association of vegetarian diet with cardiovascular risk factors compared to non-vegetarian diet.

Nutritional profile of Indian vegetarian diets--the Indian Migration Study (IMS).

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 (ß = 7.0 g/day (95% CI: 9.9 to 4.0), p < 0.0001), vitamin C (ß = 8.7 mg/day (95% CI: 4.3 to13.0), p < 0.0001) and folate (ß = 8.0 mcg/day (95% CI: 3.3 to 12.7), p = 0.001) and lower levels of fat (ß = -1.6 g/day (95% CI: -0.62 to -2.7), p = 0.002), protein (ß = -6.4 g/day (95% CI: -5.8 to -7.0), p < 0.0001), vitamin B12 (ß = -1.4 mcg/day (95% CI: -1.2 to -1.5), p < 0.0001) and zinc (ß = -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.