Shades of Fat: Why One Leads To Obesity and Another to Hibernation

Come fall, being a bear starts to look better and better. They load up on fat, sleep the winter away and wake up hungry.

There is one key, yet little-explored difference between humans and bears that explains why hibernation doesn’t work for us, and it has nothing to do with too little vacation time for an annual three-month nap. It’s a difference in types of fat.

Hibernating bears, as they fill up in the autumn months, are banking brown fat – tissue full of mitochondria that burns calories and produces heat, making it more like muscle than typical fat. Humans do have some brown fat, especially as newborns, but humans accumulate mostly white fat as they age. White fat, although it produces some beneficial substances, can in excess lead to inflammation, obesity, heart disease and other related ailments.

The medical and science communities have a wealth of information about white fat and its adverse effects. They don’t know as much about brown fat, how the human body produces it and what steps people can take to increase the amount of brown fat in their bodies, thus lowering their risk of heart disease, diabetes and obesity. A Texas Tech University researcher is working to fill in that knowledge gap thanks in part to a grant from the National Institutes of Health’s National Center for Complementary & Integrative Health (NCCIH).

Naima Moustaid-Moussa, director of the Obesity Research Cluster and a professor in the Department of Nutritional Sciences, received official notice that she won a grant from the NCCIH under award number R15AT008879. Her co-investigator in this grant is Latha Ramalingam, a research assistant professor in Moustaid-Moussa’s Nutrigenomics, Inflammation & Obesity Research Laboratory. Nishan Kalupahana, a professor at the University of Peradeniya in Sri Lanka and an adjunct professor in the Department of Nutritional Sciences and doctoral candidate Mandana Pahlavani also have been actively working on this project, for which a manuscript was just accepted for publication in the Journal of Nutritional Biochemistry.

The three-year award is for more than $430,000 to fund continued research into brown fat. Moustaid-Moussa and her team have already shown that dietary omega-3 fatty acids found in fish oil reduce inflammation in white fat. In this project, they will investigate mechanisms by which these omega-3 fatty acids activate brown fat in obese mice and in cultured brown fat cells from mice and human adipose stem cells.

“Dr. Moustaid-Moussa is a world-class researcher who has dedicated her career to solving some of the mysteries about obesity,” said Linda Hoover, dean of the College of Human Sciences. “In addition to her own research, Dr. Moustaid-Moussa has proven to be a very effective mentor for her graduate students. As a result, her students have received numerous national awards and recognitions. Her efforts demonstrate she truly is an integrated scholar.”

Brown fat is a relatively recent area of exploration; it is much less common in humans than white fat and for years has been difficult to detect and measure. As imaging technology advanced, the interest in brown fat and its role in preventing obesity and related diseases has increased. In her research thus far using animal models, Moustaid-Moussa has looked at ways to activate brown fat, allowing it to increase and whether there are nutritional means to convert white fat into brown fat.

This project will include feeding mice a diet that’s high in fat, some with a diet supplemented by omega-3s. Moustaid-Moussa and her team will use brown and white fat cells from those mice and stem cells from human adipose tissue to determine how brown fat cells are activated. The eventual goal, Moustaid-Moussa said, is to find dietary means as alternatives to pharmacological or medical interventions that will help people improve their human metabolic health and treat or prevent obesity and related diseases.

This content is solely the responsibility of Texas Tech and does not necessarily represent the official views of the National Institutes of Health.

Byline: Newswise