A reader of this blog knows that I am not a fan of supplementation. Notwithstanding, one dietary supplement that I have been kind to has been fish oil pills. It has been my understanding that these pills generally do good and in the absence of eating actual fish, are the next best thing. It turns out I was too generous. I too now cry out in capitulation, "Et tu fish oil?"
Fish oils (omega 3s) are often recommended, even by many in the medical establishment, as a natural means to lower cholesterol and prevent cardiovascular disease. Given the prevalence of heart disease in our society, it's not surprising that pills containing it are among the most widely used dietary supplements. Many fish oil marketers make claims that fish oil is not only good for preventing disease, but also reversing it. In addition, many marketers of fish oil sell mega-doses with the implication that the more you take the better.
Two recent reports shed some meaningful light on these two assertions.
In a Nutritional Research Report developed by Tufts University (Boston, MA) and prepared for the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services, Tuft's researchers concluded that the maximal positive effect of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), the two fatty acids known as Omega-3s, appears to plateau at a mean daily intake of 0.20 grams or 200 milligrams. There is no evidence that the effect of EPA and DHA on mortality phenotypes differs across populations and settings. In plain-speak, this means these findings hold true for all populations and that above 200 mg per day there is no additional benefit (it does make you fatter, however) from taking extra fish oil.
The second study looked at the benefits of taking fish oil when heart disease already exists. The study published in the Archives of Internal Medicine throws the theory into doubt: based on an analysis of 14 controlled trials in which nearly 20,500 patients with a history of heart disease were randomly assigned to take omega-3 supplements or placebo. It turns out that those taking the fatty acid pills had about the same rates of heart disease, including dying from heart attacks, congestive heart failure and stroke as did those who took placebos. The authors of the study were quick to caution that this applies to fish oil supplement pills, but may not apply to consuming fish oil by eating fish that naturally contain these fatty acids..