Low Vitamin B12: a hidden cause of diabetes explosion in India?

Ask any pregnant woman and she will vouch for the Group B vitamin known as folic acid. Chances are that her doctor has explained to her how this is a proven cornerstone of good pregnancy nutrition. 

But a new finding by a Pune-based diabetologist reveals that babies born to mothers with high folate levels and low vitamin B12 levels are more insulin resistant. Insulin resistance is the body’s inability to use the insulin it produces. It may be linked to obesity, hypertension and high levels of fat in the blood. 

Result: A considerable contribution to the epidemic of adiposity and Type 2 diabetes in India, concludes Dr CS Yajnik, diabetologist and head of Pune KEM hospital’s diabetes unit, in a paper published in Diabetologia this January. 

“We studied the association between the vitamin B12, folate and total homocysteine status during pregnancy and offspring adiposity and insulin resistance,” says Yagnik. What they found was that it led to low birthweight babies — a risk factor for Type 2 diabetes. 

THE STUDY 

The Pune researchers — including anthropometrists, statisticians, gynaecologists and medical social workers -- studied 700 pregnant women across six villages. Two thirds of mothers had low vitamin B12 levels. Their protein intake was much lower than the recommended daily allowance. 

When their children were six years old, it was found that although the kids were short and thin, they were relatively adipose as per UK standards. The test that established this was skinfold thickness. 

These babies grow into shorter, thinner (low BMI) but more adipose (higher body fat per cent and higher central fat) adults compared with whites, and have a many times higher risk of Type 2 diabetes. Children born to mothers with low vitamin B12 concentrations but high folate concentrations were the most insulin resistant. 

WHAT IT MEANS FOR INDIA 

India has the largest number of diabetics in the world, says Yajnik. This may be related to the fact that Indian babies are among the smallest in the world. The Pune study was the first to demonstrate that low birthweight of Indian babies predicts insulin resistance and adiposity in childhood. Apart from genetic and modern day lifestyle factors, the intrauterine environment may also influence the risk of Type 2 diabetes mellitus. 

WHAT’S THE BEST DIET? 

The Indian policy is to provide iron and folic acid (60 mg and 500 µg per day) to all pregnant mothers. But there is no official guideline regarding the intake of vitamin B12 as against folic acid in the country, says paediatrician Dr Urmila Deshmukh. Despite the evidence of widespread deficiency vitamin B12 supplementation is not a consideration in pregnant Indian women. 

Vegetarianism and low milk intakes contribute to low vitamin B12 status in Indians. Nutritionist Himangi Lubree says their study indicates that finding novel sources of vitamin B12 acceptable to vegetarians should be a priority now. 

Low vitamin B12 levels can affect the brain, increase the risk of stroke and risk of cognitive impairment. The ultimate source of the vitamin in nature is microbes and humans obtain it mainly from non-vegetarian food. While pilot studies are now underway on assessing whether vitamin B12 supplements are effective for children, the researchers say a balanced diet includes green leafy vegetables, milk and milk products and consumption of red meat once a week.