Think aging happens in your skin (wrinkles!), your joints (the aargh when you get out of a chair), and maybe your mind (what did I come into the living room for?)? Truth is, aging happens deep within your cells, in little structures called telomeres. New research adds to evidence that you have some control over them.

Telomeres are structures at the ends of your chromosomes that get a little shorter every time a cell reproduces, making it harder for the cell to replicate, grow, and replenish your body. Stresses, including worry, tobacco smoke, inactivity, and belly fat, shorten those telomeres faster, making your body even older. So far, only difficult things like stress reduction, meditation, and hard exercise have been found to restore telomere length. But new research suggests you might get help from a pill.

In a group of people with coronary artery disease, researchers saw that those with the most omega-3 fatty acids in their bodies also had the slowest rate of telomere shortening over 5 years. But they weren't any old omega-3s; they were EPA and DHA, the healthy fats in fish.

We recommend supplementing every day with a fish oil supplement that contains a combined total of 2,000 milligrams of DHA and EPA, or with a vegetarian source of 600 milligrams of DHA (pills from algae, which is where fish get their DHA). Side effects: EPA can add to blood thinning (desirable, unless you already have something that does that, like aspirin); we don't know of any side effects of DHA. These fats also help prevent wet macular degeneration, joint arthritis, and memory deterioration for only 15 calories a day.