Low Vitamin B12 in Pregnancy Linked to Insulin Resistance in Offspring

Low plasma vitamin B12 in the first trimester and high folate levels in the second trimester of pregnancy predispose offspring to insulin resistance, according to the results of a study.

As a part of the Pune Maternal Nutrition Study, Dr. Chittaranjan S. Yajnik from the King Edward Memorial Hospital, Pune, in western India, and his multinational colleagues evaluated the dietary intake, vitamin B12, folate, total homocysteine and methylmalonic acid levels of 700 women at 18 weeks’ and 28 weeks’ gestation.

Six hundred fifty-three offspring of these mothers were followed-up at 6 years of age with physical and biochemical measurements, body composition using X-ray absorptiometry, and insulin resistance using homeostatic models.

The plasma B12 levels were low (<150 pmol/L) in a majority of the women at 18 weeks and 28 weeks gestation, but were significantly higher among mothers whose diet included dairy products and non-vegetarian foods, the researchers report. The median red cell folate was significantly elevated at 28 weeks gestation, they note.

Insulin resistance at 6 years of age was significantly more common in the offspring of mothers who had low B12 levels at 18 weeks and high folate levels at 28 weeks of pregnancy, and was highest among those with a combination of both, Dr. Yajnik’s team reports.

Adiposity was greater among the offspring of mothers with higher folate levels, they add.
Increased plasma levels of homocysteine and methylmalonic acid as a consequence of low plasma B12 results in lipogenesis, reduced protein synthesis and reduced lean body mass, and may be the precursor of insulin resistance, the researchers postulate. "Epigenetic regulation, involving DNA methylation, may be another mechanism of nutritional programming," they add.

Dr. Yajnik stated that, “An imbalance in the vitamin B12 and folic acid levels produces the "undesirable effects.".
"Multigenerational vegetarianism means that vitamin B12 deficiency is common in Indians, but folate deficiency is relatively rare," Dr. Yajnik explained. "High folate intakes in vitamin B12-deficient mothers could increase the risk of type 2 diabetes in the offspring."

"The National Anemia Program recommends use of iron and folic acid in pregnancy but ignores vitamin B12. This needs to be reconsidered and due attention needs to be given to vitamin B12," Dr. Yajnik concluded.

Diabetologia 2008; 51:29-38.

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FACT:
Sugary Drinks Tied to Obesity, Type 2 Diabetes: Women who drink higher amounts of sugar-sweetened drinks are likelier to gain weight and develop type 2 diabetes, new research says. The study adds new fuel to the debate on the sources of weight gain and their ultimate impact on the ever-growing diabetes epidemic. Both the study’s authors and its critics agree that caloric intake is crucial to the problem.  About half of the increase in the risk of type 2 diabetes is due to the weight gain that occurs with sugar-sweetened beverages, but the other half may be related to the fact that these sugars are rapidly absorbable," said Dr. JoAnn Manson, a study co-author. "High-fructose corn syrup leads to fast and dramatic rises in glucose and insulin levels, and that can lead to insulin resistance and the development of type 2 diabetes," added Manson, chief of preventive medicine at Brigham and Women’s Hospital in Boston and a professor of medicine at Harvard Medical School.