Fats are, as they say, having a moment. Riding on scientific support for their ability to protect the heart, boost brain health, and even improve hair and skin, omega-3 fatty acids supplements garnered $3.2 billion in sales in 2012, according to the Global Organization for EPA and DHA Omega-3 (GOED). That rate is growing at a clip of 8 percent to 10 percent per year as companies roll out everything from simple fish oil pills to ultraconcentrated designer formulas and products targeted at kids and vegetarians.

With the expanding omega-3 cornucopia comes one major downside: “People are confused,” says Gretchen Vannice, RD, author of Omega-3 Handbook (CreateSpace, 2011). “We’re bombarded with marketing messages and different ways to get omega-3s, but how much, what type, and how to get them can be hard to figure out.” Here’s your fat-facts cheat sheet.

Why are omega-3s important? 

With the typical American diet now overloaded with refined oils, processed snack foods, and meats rich in omega-6 fats (which counteract omega-3s’ benefits), fat levels are badly imbalanced—with serious consequences. “A diet deficient in omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), results in altered cell membranes,” says Michael Murray, ND, author of more than 30 natural health books, including What the Drug Companies Won’t Tell You and Your Doctor Doesn’t Know (Atria, 2010). “Without a healthy membrane, cells lose their ability to hold water, vital nutrients, and electrolytes and to communicate with other cells.”

By far, most of the current omega-3s research focuses on heart health. In 2008, a seminal study published in The American Journal of Clinical Nutrition demonstrated that people who ate just 250 mg combined EPA-DHA daily were 36 percent less likely to die of a heart attack than those who ate none. Since then, numerous studies have suggested that boosting EPA-DHA intake can improve heart health by preventing irregular heartbeats and blood clots, boosting vascular function, and decreasing plaque growth and inflammation.

Then there’s eye and brain health. Studies show that DHA in particular abounds in retina and gray-matter cells and that animals who lack it at critical developmental stages are more likely to have vision problems and learning deficits.

Mounting evidence also suggests that people who get more DHA throughout life are less likely to develop dementia; one paper in The American Journal of Clinical Nutrition concluded that 180 mg daily of DHA (roughly three servings of fish per week or a 1-gram fish oil capsule daily) reduced dementia risk by 50 percent. Vannice says it’s best to start getting enough omega-3s early, rather than waiting until your senior years and trying to catch up.