A study published in the Journal of Clinical Investigation shows that dietary iron intake may suppress leptin, a hormone that regulates appetite. Iron is the one mineral that humans can’t excrete, so the more iron that is consumed the greater the likelihood that leptin levels will drop, resulting in increased appetite and the potential to overeat.
In the study, male mice were fed high (2000 mg/kg) and low-normal (35 mg/kg) iron diets for two months, followed by measuring the levels of iron in fat tissue. The researchers observed a 115% increase of iron in the mice fed a high-iron diet as compared to the mice fed the low-normal diet. In addition, leptin levels in blood were 42% lower in mice on the high-iron diet compared to those on the low-normal diet.
Results from the animal model were verified through ferritin blood tests from 76 human participants in a previous clinical study. Ferritin blood tests measure the amount of iron stored in the body. The researchers showed that fat tissue responds to iron availability to adjust the expression of leptin, a major regulator of appetite, energy expenditure and metabolism.
“We don’t know yet what optimal iron tissue level is, but we are hoping to do a large clinical trial to determine if decreasing iron levels has any effect on weight and diabetes risk,” said Don McClain, director of the Center on Diabetes, Obesity and Metabolism at Wake Forest Baptist and senior author of the study. “The better we understand how iron works in the body, the better chance we have of finding new pathways that may be targets for the prevention and treatment of diabetes and other diseases.”
