According to George Eisman, a registered dietician, the study of fatty acids is complicated, but the only two fatty acids that are truly essential for everyone are: linoleic acid (18:2, n−6), an omega-6 fatty acid; and alpha-linolenic acid (18:3, n−3), an omega-3 fatty acid, both of which are found in flax seed. The human body appears to be able to make any other necessary fatty acids from other fatty acids within the body.
Thus, the only omega-3 fatty acid that we need to eat in our diet is alpha-linolenic acid (ALA), which is found in plant foods such as flax seed.
It seems that every day we see a promotion for consuming fish oil to get the necessary omega-3 fatty acids that our body needs; but over the past decade, we have seen these claims challenged.
In 2011 Physicians Committee for Responsible Medicine (PCRM) reported:
- The American Journal of Epidemiology reports that men with higher levels of DHA, one of the omega-3 fatty acids found in fish oil, were at increased risk of developing prostate cancer.
- Researchers from Seattle’s Fred Hutchinson Cancer Research Center looked at 3,461 participants in the Prostate Cancer Prevention Trial and found that men with the most DHA in their bloodstreams were two-and-a-half times more likely to have an aggressive form of prostate cancer.
- Similar results were found in the European Prospective Investigation into Cancer and Nutrition study, where men who had the highest omega-3 levels had the highest risk for prostate cancer.
In a letter published October 31, 2000, the United States Food and Drug Administration Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements noted that known or suspected risks of EPA and DHA consumed in excess of 3 grams per day may include the possibility of:
- Increased incidence of bleeding
- Hemorrhagic stroke
- Oxidation of omega-3 fatty acids, forming biologically active oxidation products
- Increased levels of low density lipoproteins (LDL) cholesterol (bad cholesterol) or apoproteins associated with LDL cholesterol among diabetics and hyperlipidemics
- Reduced glycemic control among diabetics
And even with all this information, subsequent advice from the FDA and national counterparts have permitted health claims associated with heart health.
Note that both of these reports talk about problems associated with DHA, docosahexaenoic acid (22:6, n−3), another, but non-essential omega-3 fatty acid.
In conclusion, the evidence strongly suggests that providing that our diets give our bodies the two essential fatty acids from plant foods, our bodies will produce all the other required fatty acids that our bodies require, and in just the correct amounts. Taking supplements, particularly from animal sources, or eating animal products, causes the problems mentioned above.