For healthy adults without major medical issues, the European Food Safety Agency recommends a daily dose of 250 milligrams of combined EPA and DHA, while the National Heart Foundation of Australia suggests 500 milligrams. A NATO workshop recommended 800 milligrams per day. EPA and DHA are often taken, and measured, together.
People with heart disease, according to the American Heart Assn., should get 1 gram of EPA and DHA a day. People with high triglycerides should take 2 to 4 grams under a doctor's supervision.
Pregnant and breast-feeding women should focus on DHA, aiming for at least 200 to 300 milligrams a day, according to several expert groups. If they don't eat fish, women should take fish oil pills or supplements that have a 3-to-1 ratio of DHA to EPA, says nutritional scientist Bruce Holub of the University of Guelph in Ontario and executive director of the DHA/EPA Omega-3 Institute there. That's the same ratio found naturally in fish, he says, and getting too much EPA compared to DHA during pregnancy might diminish DHA's benefits.
Kids, says Philip Calder, a nutritionist and omega-3 researcher at the University of Southampton in England, should probably get between 100 milligrams and 250 milligrams a day.
Very few Americans reach those recommended amounts. One study found that the average pregnant woman in Canada consumed just 80 milligrams of EPA and DHA a day. Another study, which looked at everything a group of Canadian children ate over the course of a week, found that an average 2-year-old got just 19 milligrams per day, with half getting less than that. Four- to 8-year-olds did only slightly better with 55 milligrams per day. The average American adult, according to other research, gets 120 milligrams to 150 milligrams daily.
In extremely large doses, omega-3s can increase the amount of time it takes for blood to clot — a potential danger for people taking blood-thinners or those with clotting problems. Otherwise, it's hard to reach an upper limit, Calder says. People in arthritis studies take 3.5 grams of omega-3s, or nine standard fish oil pills, every day for up to a year without any problems.
"I think it is really difficult to overdose on omega-3 fatty acids," Calder says.
Foods or pills
Eating fish is an easy way to stock up. Fatty and oily fish such as salmon and mackerel score higher than lean fish, like cod or tilapia. Even within a single variety of fish, though, levels can vary widely, based on what the fish ate while it was alive.
A 100-gram serving of salmon, for example, may contain 400 milligrams to more than a gram of DHA, and from less than 200 milligrams of EPA to more than 800 milligrams.
