Published May 6, 2013
Feeding infants foods high in carbohydrates immediately after birth programs them for lifelong increased weight gain and obesity, according to the results of a UB rat pup study.
Even when caloric intake is restricted for a period of time in adulthood, this metabolic programming is not reversed, the groundbreaking study shows.
“Our hypothesis has been that the introduction of baby foods too early in life increases carbohydrate intake, thereby boosting insulin secretion and causing metabolic programming that in turn, predisposes the child to obesity later in life,” he explains.
In the study, newborn rat pups were fed special milk formulas that were either similar to rat milk or enriched with carbohydrate-derived calories.
The pups that consumed the high-carbohydrate (HC) milk formula received a different kind of nourishment than they normally would, which metabolically programmed them to develop a precursor for obesity and type 2 diabetes, Patel and his collaborators found.
An altered nutritional experience during the immediate postnatal period can modify the way organs in the body develop, resulting in programming effects that manifest later in life, explains Patel, who is also associate dean for research and biomedical education.
“During this critical period, the hypothalamus, which regulates appetite, becomes programmed to drive the individual to eat more food,” he says.
For more than 20 years, Patel and his UB colleagues have studied how the increased intake of carbohydrate-enriched calories just after birth can program individuals to overeat.
When the HC rats were 3 weeks old, they were weaned onto rat chow either with free access to food or with a moderate calorie restriction, so that their level of consumption would be the same as pups reared naturally.
“When food intake for the HC rats was controlled to a normal level, the pups grew at a normal rate, similar to that of pups fed by their mothers,” Patel says.
“But we wanted to know, did that period of moderate calorie restriction cause the animals to be truly reprogrammed? We knew that the proof would come once we allowed them to eat ad libitum, without any restrictions.”
The study found that when the HC rats underwent metabolic reprogramming for development of obesity in early postnatal life and then were subjected to moderate caloric restriction, the programming was suppressed but not erased, explains Patel.
“This is the first time that we have shown in our rat model of obesity that there is a resistance to the reversal of this programming effect in adult life,” he says.
This study involved only moderate caloric restriction, so Patel and his colleagues would like to investigate whether more severe caloric restriction for a limited period can result in true metabolic reprogramming to normal metabolic phenotype.
“Many American baby foods and juices are high in carbohydrates, mainly simple sugars,” says Patel.
He suggests that parents follow the American Academy of Pediatric guidelines to avoid metabolic reprogramming that predisposes babies to obesity.
These guidelines state that solid foods should not be given before a baby is about 6 months old.
Because caloric restriction does not reverse programming for obesity, addressing the obesity epidemic in the United States requires true lifestyle change, including permanent caloric restriction.
“As long as you restrict intake, you can maintain normal body weight,” Patel says.
The study, supported by the National Institute of Diabetes and Digestive and Kidney Diseases, was published in the American Journal of Physiology: Endocrinology and Metabolism in March; it was published online in December.
Patel’s co-authors, both from the Department of Biochemistry, are: