Sunday, December 11, 2011

Help! My fish oil has gone bad! by Jerry Brainum

Omega-3 fatty acids, as found preformed in fatty fish and fish oil, provide a variety of health benefits. The primary benefits are related to cardiovascular health. Fish oil lowers elevated blood triglyceride (fat) levels, which is a risk factor for cardiovascular disease (CVD). Fish oil also seems to help control blood pressure, another CVD risk factor when elevated.Based on countess studies published over the last few years, the recommendation is to consume at least two fatty fish meals per week (such as mackerel,herring, sardines, and others), or ingest fish oil supplements if you refuse to eat fish.
    But there is a problem with fish oil supplements. Fish oil is a high polyunsaturated fat source. What this means is that it is prone to oxidation and rancidity. Oxidized fats have been shown to directly damage blood vessel linings, leading to accelerated atherosclerosis and subsequent CVD. Several studies that have tested commercial fish oil supplements have found that the supplements did contain oxidized fats. Since fish oil is prone to oxidation, does this mean that consuming fish oil may do more damage than good?
    Not according to a new study. The study consisted of healthy subjects with an age range of 18 to 50, who were divided into three groups. The first group ingested 8 grams of day of fish oil, which was consumed with two meals. The second group ingested 8 grams a day of oxidized fish oil capsules. The third group ingested 8 grams a day of high-oleic safflower oil, an omega-6 fat. Fasting blood samples were collected at the start of the study, and at weeks 3 and 7, with the study lasting 7 weeks.To determine the effects of oxidation, several tests that measure oxidative by-products were administered, as well as tests of the endogenous anti-oxidant system in the body (glutathione) and vitamin E levels to see if any changes occurred in the oxidative defense system of the body.
     The results after 7 weeks (and also at the 3-week mark) showed that both the fresh and oxidized fish oil were equally effective at increasing blood levels of omega-3 fatty acids. But no markers of oxidative stress were affected, nor was any indication of lipid peroxidation affected, or inflammation markers. In short, ingesting the oxidized fish oil had no bad effects. How can this be? The gastrointestinal tract acts as a barrier against the uptake of oxidized lipids into the blood. It this manner, it filters the potentially dangerous oxidized fats out of the fish oil. Although there is no evidence that is what happened in this study, this explanation is plausible, and would explain the lack of any side effects after ingesting oxidized fish oil for 7 weeks.
     So next time you read how "cheap" fish oil supplements contain oxidized fat and can harm your health, so you should instead purchase that $85 bottle of fresh "pharmacological grade" fish oil, just turn the page and save yourself some money.

Ottestad, I ,et al. Oxidized fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomized controlled trial.Br J Nut 2011: in press.

©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.

Have you been ripped off  by supplement makers whose products don’t work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at


The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.


See Jerry's book at


Want more evidence-based information on exercise science, nutrition and food supplements, ergogenic aids, and anti-aging research? Check out Applied Metabolics Newsletter at