The omega-3 fatty acid docosahexaenoic acid, better known as "DHA," is available in fish oil capsule supplements and baby formulas. DHA is found naturally in foods like coldwater fish, but some health-conscious individuals take additional DHA in an effort to promote general health. Like many supplements, too much of a good thing comes with consequences.
The most commonly reported adverse side effects of taking too much supplementation containing DHA are severe headaches, nausea, vomiting, dizzy spells and fainting. Normally, these side effects subside upon cessation of taking excess amounts of DHA, either in supplement form in food form. If you are experiencing these types of symptoms, you should stop taking any DHA or DHA-rich foods and seek advice from a doctor. At the time of publication, no overly harmful or potentially fatal side effects have been recorded from ingesting too much DHA. Still, it pays to err on the side of caution to reduce your chances of experiencing the known negative side effects.
How Much is Too Much
There seems to be some controversy over how DHA constitutes as too much. At the time of publication, the U.S. Food and Drug Administration has yet to post standards for what actually constitutes as an “overdose” of DHA, while the FDA’s European counterpart recommends users not to exceed 250 mg a day. Conversely, Australian doctors advise their patients not to exceed 500 mg of DHA a day. According to Emily Sohn, a contributor to "The Los Angeles Times," most experts from the American Heart Association advise heart patients take no more than 1 gram day and those with high triglyceride “blood fat” counts take between 2 and 4 g. Many obstetricians and gynecologists recommended pregnant and lactating mothers consume between 200 to 300 mg of DHA daily.
Most Americans already obtain those amounts of DHA regularly in their diets, thus negating the need to take additional supplementation. According to the authors of “Nutrition: Concepts & Controversies,” plenty of DHA can be found in salmon and halibut, two examples of coldwater fish. The authors caution that the amount of DHA consumed by eating these types of fish vary according to portion size, the overall size of the fish when it was caught and the fish’s diet before it was harvested, so more or less than the above amounts of DHA may be consumed.
A Word of Caution
If you are interested in taking a supplement containing DHA, such as vitamin E or fish oil capsules or upping your intake of DHA-rich foods, you should first consult with a doctor or registered dietitian. An overabundance of DHA in the blood slows down your body’s ability to clot, thus hampering your immunity to disease and your ability to recover from wounds. If you are taking a prescribed blood thinner for a heart ailment, you should definitely speak to the physician prior to taking additional DHA.