omega-3 fish oil

Omega-3s are a type of fat that occurs naturally in foods and in the body, and they are also sold as dietary supplements such as fish oil. According to NCCIH, most research focuses on EPA and DHA — the omega-3s concentrated in seafood and cold-water fish like salmon, mackerel, and tuna — along with ALA, which comes from plant oils such as flaxseed.

The evidence is mixed and often weak. NCCIH notes that eating seafood rich in EPA and DHA is part of a heart-healthy diet, but EPA/DHA supplements have generally not been shown to protect the general population against heart disease; any benefit appears mainly in people who already have heart disease or high triglycerides. Omega-3 supplements can lower triglycerides by about 15 percent and may modestly help rheumatoid arthritis symptoms (evidence rated low). For conditions such as depression, ADHD, and dry eye disease, the evidence is uncertain, conflicting, or no better than placebo. NCCIH states that, overall, the health benefits of omega-3 supplements are unclear, and that whether taking them is beneficial is uncertain.

There is no single established supplement dose for general health. Federal dietary guidance recommends that adults eat 8 ounces or more of a variety of seafood per week rather than relying on supplements, and NCCIH cites an analysis suggesting that consuming about 1 gram per day of omega-3 fatty acids provides some cardiovascular benefit. Because the appropriate amount — and whether a supplement is suitable for you at all — depends on your individual health, talk to a clinician or pharmacist before starting omega-3 supplements, particularly at higher doses.

NCCIH reports that side effects of omega-3 supplements are usually mild. It is especially important to consult your (or your child's) health care provider before use if you are pregnant or breastfeeding, take medicine that affects blood clotting, or are allergic to seafood. As with any complementary approach, discuss omega-3 supplement use with your health care providers so you can make shared, well-informed decisions, and do not change prescribed medications without consulting them.

According to NCCIH, side effects are usually mild. Reported effects include an unpleasant taste, bad breath, body odor, and headache, as well as digestive complaints such as heartburn, nausea, and diarrhea.

NCCIH advises consulting a health care provider before taking omega-3 supplements if you take medicine that affects blood clotting, such as anticoagulant ("blood thinner") drugs. People who are pregnant, breastfeeding, or allergic to seafood should also check with a provider first. Discuss any potential interactions with your clinician or pharmacist before combining omega-3 supplements with prescription medications.