Researchers at the Joslin Diabetes Center, Harvard, and the Ohio State University have identified, for the first time, a fat molecule that circulates in the blood after exercise that causes metabolic changes linked to physical activity, and boosting it may help reduce triglyceride levels, improve cardiovascular health, and regulate weight, says a recent study.
The study found that even a short bout of moderate exercise increased levels of a lipid called 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME) in male, female, young, old, sedentary, and active human subjects. In a previous study, researchers had found that blood levels of the same lipid shot up when subjects were exposed to cold.
"Our data provide some of the first evidence that exercise can alter the endocrine function of brown fat by increasing 12,13-diHOME," says co-author Laurie Goodyear, senior investigator at the Joslin Diabetes Center and associate professor at Harvard Medical School. "These data highlight another mechanism for the beneficial effects of exercise."
The lipid 12,13-diHOME is produced by brown adipose tissue (BAT), or brown fat, which burns more calories than the white fat linked to type 2 diabetes and heart disease. Newborns burn a reserve of brown fat to stay warm, but the purpose of the few grams of brown fat that adults retain is unclear.
While cold exposure is known to stimulate BAT, while previous studies have shown that exercise decreases BAT activity. ", so to see that 12,13-diHOME was released from BAT after both exercise and cold exposure was unexpected," said co-author Kristin Stanford of the Ohio State University's Wexner Medical Center.
In mice, both a single burst of exercise and longer-term training increased circulating 12,13-diHOME. Surgically removing the animals' brown fat eliminated the effect, suggesting that brown fat itself generates the lipid. The study found that BAT reacts in subjects after both exercise and cold exposure might lead to new ways to manipulate it.
The study has appeared Tuesday, May 1 in the journal Cell Metabolism.