Lack of adequate prenatal nutrition increases the risk of developing Type 2 diabetes, researchers at Joslin Diabetes Center have found. A study on mice has indicated that poor prenatal nutrition causes impairment in the activity of the pancreas later in life, hampering the production of insulin according to the levels of blood glucose. The study, which was published in the March edition of Diabetes, has provided some reasons for the previous links found between low birth weight and diabetes.
Joslin Medical Center’s Dr Mary-Elizabeth Patti, who is also the assistant professor of medicine at Harvard Medical School, headed the research. “The bottom line is that if you don’t have delivery of enough nutrients from the mother to the baby, the baby’s pancreatic cells will be programmed abnormally,” she said adding that the effect doesn’t show up until adolescence or adulthood.
Under the study, researchers separated pregnant mice into two groups, with those in one group, called the control group, eating as much as they wanted throughout the pregnancy. The other group, though given enough nutrition in the first two weeks, was given only half the required food in the third week. At birth, the babies of the second group weighed 23 per cent less than that of the first.
Even though the underweight mice caught up with the others soon, a close monitoring of their blood sugar levels upon maturity showed differences between the two groups. Towards the completion of six months, the low birth weight babies started showing very high blood glucose levels, as much as that of a person with full-blown diabetes. “The levels had spiked abnormally to 500 mg/dl,” Dr Patti said.
The study, however, showed that the risk was not because of underdeveloped pancreas. The pancreas size and numbers of pancreatic beta cells, which produce insulin, remained the same in both groups. But cultures of the beta cells revealed that the low birth weight mice responded abnormally to glucose. Their cells were ‘programmed’ to secrete a limited amount of insulin, irrespective of the signal they received from glucose. In addition, the impairment was found to be permanent.
Certain experts, however, questioned the relevance of the findings in relation to humans. Dr Rebecca Anne Simmons, assistant professor (pediatrics), University of Pennsylvania, felt that the nutrition that the undernourished pregnant mice received was far less than what is seen in humans. She also felt that the damage caused to the insulin-producing cells occurred because of lowered blood supply to the fetus, and not because of malnutrition. Dr Patti, however, said that those born with low weight should pay special attention to prevention tactics, including exercise and weight control to minimize insulin resistance.
According to the Centers for Disease Control and Prevention (CDC), the incidence of low weight babies in the United States has gone up by 12 per cent between 1980 and 2000 among babies weighing 2500 gm, and 24 per cent in babies weighing 1500 gm or less. In 2002, around 314,077 low birth weight babies were born, representing 7.8 per cent of all births that year.
