woman on scale for obesity treatment

BWH research is shedding new light on fat, which may lead to shedding of pounds.

By now, it’s common knowledge that not all fats are created equal. But did you know that this goes not just for the fats in our foods, but also the fat in our bodies?

When it comes to diet, you control which fats you eat. But what about the fat inside your body? Inside, there is visceral fat – the fat around the organs that expands the waistline and is linked with diabetes and heart disease. Then there is subcutaneous – the less dangerous fat under the skin. Separately, we also have white fat, which stores energy, and  brown fat, which releases energy.

When it comes to fat, brown may be the color of choice, Studies suggest that increased brown (good) fat is associated with being leaner, even without additional exercise, since the brown fat burns more calories.

Now, new research from Brigham and Women’s Hospital (BWH) is shedding new light on fat, which may lead to shedding of pounds. Researchers led by Dr. Jorge Plutzky, director of the BWH Vascular Disease Prevention Program in the Cardiovascular Division, recently discovered a way to give bad white fat the characteristics of good brown fat. In the battle against obesity, this may prove to be very good news indeed.

The question is: How do you make bad fat turn good? The secret, according the BWH research team, is to block a particular enzyme (Aldh1al) found in white cells. Once that enzyme is inhibited, the white fat cells start acting like brown cells.

In the BWH study, researchers turned off the Aldh1al enzyme in overweight mice by injecting antisense molecules (which silence a specific gene). The result: The mice receiving the Aldh1a1 antisense lost weight, decreased their visceral fat, and lowered their glucose levels as compared to mice injected with a nonspecific, random antisense. One defining characteristic of brown fat is its ability to release energy as heat. In the study, the mice with inhibited Aldh1a1 became protected against exposure to cold – a classic indicator of brown fat and its ability to generate heat by oxidizing fat. Antisense approaches are also being pursued to treat other diseases in humans.

“Brown fat, and mechanisms that might allow white fat to take on brown fat characteristics, has been receiving increasing attention as a possible way to treat obesity and its complications,” notes Dr. Plutzky. However, more research is still needed before the findings can have clinical benefits in humans. This work, by Dr. Plutzky, the first author Dr. Florian Kiefer, and their colleagues, appeared online on May 6, 2012 in the journal Nature Medicine.

In the meantime, until Aldh1a1 studies yield new therapies, the battle of good versus bad fat, in both our bodies and our diets, will stay focused on what we eat and our activity.

– Linda W., Lori S.

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