There's little doubt remaining that omega-3 fatty acids from fish oil reduce dangerous events from heart disease (heart attack and sudden death), abnormal heart rhythms (particularly atrial fibrillation), stroke, and are an effective therapeutic agent to reduce triglycerides. In fact, fish oil is so effective that a prescription form is now available, in addition to the over-the-counter nutritional supplements that have been available for several years.
A typical fish oil capsule 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.
Is that enough? Is more desirable? Is less sufficient?
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.
What if you are trying to reduce triglycerides? (The National Cholesterol Panel Adult Treatment Panel-III guidelines suggest triglycerides ≤150 mg/dl; in our heart disease reversal program, we aim for <60 mg/dl.) Then higher doses may be required. Four standard fish oil capsules, providing 1200 mg EPA and DHA, reduces triglycerides around 20%. 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. Prescription Lovaza® contains 850 mg omega-3s per capsule. (Of course, you should be working with your health care provider when high triglycerides are being treated).
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.