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Scientists at California’s Loma Linda University suggest that a vegetarian diet increases mortality. The benefits may be coming from lower blood pressure and better cholesterol levels compared with those who eat meat. Vegetarian diets also tend to be higher in fibre and lower in saturated fat. Caloric intake didn’t affect things one way or another in the study, reports Kalyan Ray
This news will cheer millions of Indians who prefer a vegetarian diet. Diligently following diets of more than 73,000 individuals from the US and Canada for six years, medical researchers have claimed that a vegetarian diet lowers death risk. Men seem to benefit more too.
For years, researchers have explored the relationship between diet and mortality. Previous studies have found links between vegetarian diets and reductions in risk for several chronic diseases including hypertension, metabolic syndrome, diabetes mellitus and ischemic heart disease (IHD).
Now scientists at Loma Linda University in California examined all-cause and cause-specific mortality in a group of 73,308 men and women. They were members of a specific Church-going community called Seventh-day Adventists, which promotes vegetarian diet.
Researchers assessed the subjects using a questionnaire that categorised study participants into five groups: non vegetarian, semi-vegetarian (very low animal protein consumption), pesco-vegetarian (includes fish and seafood), lacto-ovo-vegetarian (includes dairy and egg products) and vegan (excludes all animal products).
For some of the analyses in the study, the last four categories were broadly called vegetarians, which was compared with non-vegetarians.
Among the 73,308 individuals, there were 5,548 (7.6 per cent ) vegans; 21,1777 (28.9 per cent) lacto-ovo-vegetarians; 7194 (9.8 per cent) pesco-vegetarians; 4031 (5.5 per cent) semi-vegetarians and 35,359 (48.2 per cent) non-vegetarians. The average period for the study subjects following their basic dietary pattern was 21 years for vegans, 39 years for lacto-ovo-vegetarians, 19 years for pesco-vegetarians, 24 years for semi-vegetarians and 48 years for non-vegetarians.
There were 2,570 deaths among the study participants during the follow-up period of almost six years. The overall mortality rate suggests vegetarians were 12 per cent less likely to die from any cause. Vegans saw a 15 per cent lower risk of death, which varies from nine per cent among lacto-ovo-vegetarians to 19 per cent in fish and sea-food eaters. For semi-vegetarians, the risk is 8 per cent less than non-vegetarians.
“It is likely to be a combination of reduced meat intake and increased intake of a variety of healthy plant-based whole foods that brings down the risk,” Michael J Orlich, the corresponding author at Loma Linda University told Deccan Herald. The findings have been published in the June 3 issue of JAMA Internal Medicine. The benefits may be coming from lower blood pressure and better cholesterol levels compared with those who eat meat. Vegetarian diets also tend to be higher in fibre and lower in saturated fat. Caloric intake didn’t affect things one way or another in the study.
Several other factors
The study, however, does not necessarily mean avoiding meat is what lowered the risk of dying. There could be others factors beyond meat and vegetable consumption.
Vegetarians, for instance, tend to be more likely to be married, have more education and exercise more, all variables that could lead to a longer life. They are also less likely to smoke or drink.
“In our study, vegans, lacto-ovo vegetarians, and pesco-vegetarians, as we defined them, all showed reduced risk of death compared to non-vegetarians. We do not yet have enough statistical power to meaningfully compare these vegetarian groups to each other,” he said.
Asked whether the results would be applicable to a vast majority of Indian who prefer vegetarian diet, Orlich said it would depend how similar the diets are between the two groups. Vegetarian diets with an emphasis on a variety of whole plant foods, whole grains, legumes and nuts and lower in added sugars, added fats, and refined foods would likely show similar benefits.
Orlich’s colleague in the university and one of the co-authors, Pramil N Singh, in a separate paper in February claimed a substantial increase in the prevalence of diabetes, coronary heart disease and stroke in India points to the occurrence of an epidemiologic transition due to a higher prevalence of traditional cardiovascular disease risk factors such as diet (higher saturated fat and meat intake), physical inactivity, and tobacco use.
The Loma Linda University researchers found faith-based Indian vegetarians who changed their diet pattern from zero meat intake to weekly meat intake during a 17-year period, experienced weight gain, obesity, an increased risk of non-communicable disease (diabetes, stroke, and CHD), and a 3.6-year decrease in life expectancy.
“Evidence for this process occurring in rural and urban India is emerging. The prevalence of overweight or obesity cases in rural areas exceeds 20 per cent,” Singh said.
High-risk profile
Moreover, non-communicable disease biomarker data from Asian Indians have long raised the possibility of an ‘Asian Indian Phenotype’ which produces a high-risk metabolic profile (such as insulin resistance, metabolic syndrome, elevated homocysteine and inflammatory cytokines) that makes Asian Indians especially sensitive to excess body fat, he suggested in a paper presented at a conference in February. The WHO proposed a more sensitive indicator (body mass index greater than or equal to 23) of overweight or obesity for Asian populations and, using this cut point, large-scale prevalence surveys in South India indicate more than 30 per cent of rural adults are either overweight or obese, he said.
“The focus of our study was on the relationship of diet to death risk. Our vegetarians, particularly vegans, also tended to be a lot leaner than non-vegetarians. The mean BMI for our vegans (adjusted for age, race, and sex) was 24.1 kg/meters-squared compared to that for non-vegetarians of 28.3,” Olrich summed up.