How Much Omega-3 Should You Take?

by William Davis, M.D. Health Professional

Many studies have shown that supplementing with omega-3 fatty acids from fish oil may reduce dangerous events from heart disease and improve triglycerides. However, a 2018 scientific meta-analysis found that Omega-3 supplementation may not have the protective impact it was once believed to provide. Further dose-dependent studies have been called for to determine effectiveness.

Fish oil supplementation is available by prescription or over the counter. A typical fish oil capsule that is obtainable at most health food stores, pharmacies, or even department stores contains 180 mg of the omega-3 EPA, 120 mg of the omega-3 DHA, for a total of 300 mg per capsule. Many bottles will suggest a dosage of 2-3 capsules per day.

How much omega-3 do you need?

The dose of omega-3 fatty acids depends on what you are using it for. For instance, if you are 30 years old and are just looking to reduce the likelihood heart disease in your lifetime, then the suggested dosage on the label of 2-3 capsules per day is reasonable advice. This daily dosage approximates the two servings of fish per week that has been shown in several large studies to be enough to impact on dangerous heart events.

If you're trying to improve triglycerides, higher doses may be required. Four standard fish oil capsules, providing 1200 mg EPA and DHA, may reduce triglycerides around 20 percent. Higher doses reduce triglycerides an even greater amount. A solid dose for high triglycerides is 1800 mg per day or more (six capsules of the standard supplement). When doses get this high, it may be time to consider a more concentrated form of fish oil. Some over-the-counter nutritional supplements contain 500, 600, and all the way up to 850 mg omega-3 fatty acids per capsule.

Are omega-3 supplements safe?

Fish oil is very safe even at high doses with virtually no side-effects beyond stomach upset or belching (which can be minimized by taking with meals, refrigerating the capsules, or taking enteric-coated fish oil tablets). Occasionally doses of omega-3s as high as 5000 mg or more are required for unusual disorders like "familial hypertriglyceridemia," in which triglycerides can reach into the thousands, and lipoprotein(a), a high-risk marker for heart disease. Dosages this high should only be prescribed by your doctor.

Incidentally, along with reducing triglycerides, fish oil raises HDL a few points, reduces the important triglyceride-containing particle, very low-density lipoprotein (VLDL), and dramatically accelerates the clearance of after-eating by-products of food, all of which translate in to reduced risk for heart attack and stroke.

How are omega-3 fatty acids tied to heart health?

How about the dose of fish oil for confident reduction of heart attack and sudden death? According to the GISSI-Prevenzione Trial of 11,000 participants, a dosage of 850 mg EPA and DHA per day provided substantial benefit: 28 percent reduction in heart attack, 45 percent reduction in sudden death. Benefits began as soon as three months after the starting of supplementation. (Interestingly, omega-3s exert no cholesterol-reducing benefit at all and, in fact, may increase LDL cholesterol modestly).

However, as with most science, there are studies that show opposing views. In the 2018 meta-analysis, scientists concluded that Omega-3 supplementation at 1g/d did not provide significant benefits to those with pre-existing coronary heart disease, history of heart attacks, or other cardiovascular issues. These scientists called for further studies on higher doses to determine efficacy.

For reduction of heart rhythm disorders, the dosage of omega-3 is not well sorted out. However, omega-3 doses of 1000-4500 mg per day have been studied, with most studies suggesting significant reduction in the occurrence of abnormal heart rhythms. Benefits may take many weeks or months to develop and so the omega-3s from fish oil are most effective as a preventive strategy, not an acute treatment once rhythms occur.

A final note about omega-3

Omega-3 is one of the most common independently taken and doctor prescribed nutritional supplements on the market today. The benefits of fish oil continue to be studied for myriad health conditions and ailments.

William Davis, M.D.
Meet Our Writer
William Davis, M.D.

William R. Davis is a Milwaukee-based American cardiologist and author. He wrote for HealthCentral as a health professional for Heart Health and High Cholesterol.