Body fat supports your health in surprisingly complex ways

Too much body fat isn’t healthy, but some kinds can be beneficial DR RAY CLARK & MERVYN GOFF/SCIENCE PHOTO LIBRARY If you thought body fat was just a passive storage depot for calories, think again. Research increasingly suggests that it plays an important role in our overall health , with two studies shedding new light on its complexity. Fat exists in several forms. For instance, there’s white fat, which stores energy and releases hormones that influence metabolism; brown fat, which generates heat; and beige fat, which sits somewhere in between, switching on heat production under certain conditions. Even within these categories, location matters: fat under the skin is generally less harmful, while fat deep inside the abdomen - known as visceral fat - is strongly linked to inflammation, type 2 diabetes and heart disease. Advertisement The latest research adds further flesh to this picture, suggesting that fat, or adipose tissue, actively helps to regulate blood pressure and coordinate immune responses at key locations. In one of the studies, Jutta Jalkanen at Karolinska University Hospital in Stockholm, Sweden, and her colleagues mapped the cellular architecture of visceral fat from multiple locations within the abdomen. They found that epiploic fat, which wraps around the large intestine, is unusually rich in immune cells, as well as specialised fat cells that produce inflammatory proteins associated with immune activation. Further experiments showed that microbial products originating in the gut trigger these fat cells to activate nearby immune cells. “Our work shows that fat depots appear to be specialised according to their anatomical location, and those that sit right next to the intestine seem particularly adapted for immune interaction,” says Jalkanen. Free newsletter Sign up to Eight Weeks to a Healthier You Your science-backed guide to the easy habits that will help you sleep well, stress less, eat smarter and age better. Although the study involved people with obesity , Jalkanen suspects that epiploic fat serves similar core functions in people of all body weights, since everyone has some fat surrounding their intestine. “The intestine is constantly exposed to nutrients, microbial products and substances coming from our environment,” says Jalkanen. “Having fat tissue nearby that can sense, respond to, and help coordinate immune reactions could provide an additional layer of protection.” In obesity, however, this system may become chronically overactivated. Eating too much, or too much of certain foods, and having particular bacterial compositions within the gut microbiome could potentially drive persistent immune signalling in intestinal fat, contributing to the low-grade inflammation linked to a range of metabolic conditions, such as type 2 diabetes and obesity. The second study reveals another unexpected role for fat: controlling blood pressure. Mascha Koenen at The Rockefeller University in New York and her colleagues set out to understand why obesity, characterised by excess white fat, is linked to high blood pressure, while brown and beige fat appear to be protective. They focused on perivascular adipose tissue, a fatty layer rich in beige fat calls that surrounds blood vessels. In mice...

Preview: ~500 words