Scientists figure out what makes fish oil so good for you


This is a corrected version of the original post; see the note below.

You’ve probably heard of omega-3 fatty acids, the nutrients that make fish oil so healthy. You may even have heard of particular ones, such as DHA (docosahexaenoic acid), ALA (alpha-linolenic acid) or EPA (eicosapentaenoic acid).

But unless you’re one of the scientists who worked on a study being published in Friday’s edition of the journal Cell, you surely have no idea why omega-3 fatty acids are so good at tamping down inflammation and enhancing sensitivity to insulin. The study is rather dense, so we’ll do our best to boil it down for you.

Researchers from UC San Diego, Tethys Bioscience of West Sacramento, and Shiga University of Medical Science in Japan figured out that omega-3s stimulate an important cell signaling molecule known as GPR120. This molecule is particularly popular in fat cells. It’s also abundant in a type of white blood cells that promote inflammation. Normally, inflammation helps the immune system do its job, but when inflammation becomes chronic it can lead to problems like insulin insensitivity.

When normal mice ate a high-fat diet, they gained weight. That extra fat triggered chronic inflammation and caused the mice to have trouble responding to insulin, which can lead to Type 2 diabetes. But after having their chow supplemented with omega-3s, the fatty acids took care of the inflammation and the mice were able to respond normally to insulin once again.

To prove that GPR120 was the key to this chain of events, they repeated the same experiment in mice that were genetically manipulated so they couldn’t make the molecule. Like the normal mice, they gained weight on the high-fat diet. But the addition of omega-3s did nothing to alleviate their symptoms.

It may be awhile before scientists are able to use these findings to come up with a drug or supplement that would make people healthier. One possibility is to develop a small molecule that does an even better job of activating GPR120, they said.

For a primer on omega-3 fatty acids, check out this story from the Health section.

[For the Record, added at 8:50 p.m. Sept. 9: We originally referred to a key cell signaling molecule as GRP120. We’ve changed this post to use the correct name, GPR120.]

-- Karen Kaplan / Los Angeles Times