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.

EPA, DHA, and ALA: What is the difference? 

Omega-3 fatty acids come in various forms, each with their own unique benefits. DHA is a structural fat that makes up the brain, nervous system, and eyeballs and produces compounds critical for cognitive health. EPA produces anti-inflammatory compounds and lowers heart-damaging triglycerides. Alpha-linolenic acid (ALA)—found in vegetarian sources such as hemp foods, flaxseeds, leafy green vegetables, and chia seeds—can counteract the pro-inflammatory impact of eating too many omega-6 fatty acids and (to a limited degree) be converted to DHA and EPA in the body.

EPA and DHA get most of the credit for omega-3s’ health benefits. However, you might assume that if you’re getting enough ALA—often the source of omega-3s in fortified foods—you’re covered. That’s not the case (see number 5 below).

How much should I get? 

Murray recommends 1,000 mg EPA-DHA (not just “fish oil”) per day for general health and as much as 3,000 mg daily for specific health concerns, such as heart disease risk. Some practitioners worry that taking too much can lead to excess bleeding or interfere with blood sugar control, but in 2012 the European Food Safety Authority published a statement saying that people can take as much as 5,000 mg EPA-DHA per day without increasing bleeding risk or impacting metabolism. For higher amounts, it’s still best to consult a doctor; ask for a blood test to check your current levels.

Can I get enough omega-3s from food? 

“Absolutely, but with caveats,” says Stuart Tomc, CNHP. First, cut back on foods high in omega-6s, such as safflower, soybean, and corn oils; these promote inflammation and appear to interfere with the conversion of ALA to EPA-DHA. Next, enjoy two to three servings of oily fish, such as sardines and wild-caught salmon, per week, and top it off with ALA via greens, chia seeds, hemp oil or seeds, and flaxseed meal. The more omega-3s you get from food, the fewer pills you’ll need.

I’m a vegetarian. How can I get enough EPA and DHA? 

“It’s very difficult,” Murray says. Studies show vegetarians take in only about
5 mg EPA and 33 mg DHA daily, far short of what dietitians recommend. Although you can load up on plant-based ALA, the body converts less than 10 percent ➻ of it to EPA and less than 1 percent to DHA, according to a 2006 review. That’s of particular concern for pregnant and nursing women, whose babies depend on EPA-DHA for proper development. Vannice’s advice: Take an algae-based supplement (one of the few vegetarian sources naturally rich in DHA), and eat DHA-fortified egg yolks and other foods.

What is krill? 

Antarctic krill are tiny, shrimplike crustaceans that feed on algae, accumulating long-chain EPA and DHA in the process. Because Antarctic waters are among the cleanest on earth and krill are at the bottom of the food chain, they contain fewer environmental contaminants than fish. Krill oil pills cost more and don’t contain as much EPA and DHA as a typical fish oil capsule, but krill’s omegas have a phospholipid molecular structure more similar to human cell membranes than that of fish oil—which, fans say, makes krill oil easier to digest and absorb.

Although there’s not yet enough research to prove those qualities, in a new, double-blind, randomized trial involving 300 people with borderline or high triglyceride levels, those taking 4 grams krill oil daily for 12 weeks lowered their triglycerides by 10 percent without increasing LDL (bad) cholesterol. Other benefits: “About half the people who use krill had previously taken fish oil and stopped because they had problems with fish burps,” says Adam Ismail, executive director of GOED. “They don’t have those problems with krill oil.” Krill capsules are also much smaller and easier to swallow than typical fish oil pills.

Do the oceans have enough fish to meet the demand for fish oil supplements? 

For now, yes. Ismail says roughly 80 percent of fish oil supplements are derived from anchovies (which have the highest EPA-DHA concentration of any fish) from one fishery in Peru. Currently, demand doesn’t outstrip supply. “But if the demand keeps growing the way it is, in three to four years we may reach the limits of what the anchovy fishery can provide,” Ismail says. With that in mind, companies are working on efficiencies to produce more EPA-DHA using fewer fish. Others are turning to different sources, such as krill, salmon, menhaden, and algae.

What about contaminants like heavy metals? 

In reality, supplements probably contain fewer toxins than whole fish, Ismail says. Most fish oil purveyors remove heavy metals like mercury and lead during the manufacturing process. And supplements made from virgin, unprocessed oils such as krill or salmon tend to come from pristine waters with few contaminants. “Within the past year we tested 60 products from shelves around the world, and we never found one that had detectable levels of lead, cadmium, or arsenic,” Ismail says. Another recent study found that although every product tested contained mercury, it was only in trace amounts.

That said, you’re better off choosing a medium- to high-grade product, says Vannice. “The least expensive fish oil usually has the lowest concentration per pill, and it may not have the attention to purity or freshness that other products do,” she says.

Should children take EPA and DHA supplements?

If kids aren’t getting enough EPA-DHA from their diets—which most don’t—then yes, says Gretchen Vannice, RD, who adds that omega-3s are “absolutely critical in infant development.” In addition to nurturing cells in growing organs and providing a lipid barrier that plumps up skin—making the complexion and hair look more healthy (a bonus for teens)—long-chain fatty acids may also combat attention deficits and behavior issues, she says.

“We know that children with ADHD and other focus problems have lower omega-3 levels in their blood compared with other children, and some clinical trials show supplementation yields benefit,” Vannice says. One 2012 study looked at 90 children ages 7 to 12 who rated high on ADHD measures. Some were given 500 mg EPA-DHA fish oil daily; others were given safflower oil. After four months, those with boosted DHA levels showed significant improvements in reading and behavior problems. Another 2012 trial tracked 224 kids ages 7 to 9 who scored poorly on reading tests. After supplementing with 600 mg daily of algae-based DHA, the poorest readers’ scores improved as much as 50 percent above expectations.

Not all studies have been so encouraging. One recent review of 13 trials with 1,011 subjects found “little evidence that supplementation provides any benefit for the symptoms of ADHD” and lamented weaknesses in existing studies.

Vannice agrees more research is needed on the EPA-DHA-behavior link. But there are plenty of other reasons growing kids should get enough omega-3s. “It’s like making a cake; if you forget the oil, the recipe is just not going to be quite right.” She recommends at least 500 mg daily via food and supplements. Consider liquid formulas and chewables until kids can swallow pills.