By Joseph Brownstein
Among the many nutrition supplements trumpeted for potential health benefits, fish oil supplements have been among the most ballyhooed. But as the research on fish oil rolls in, it’s unclear whether the supplements provide all the touted benefits, or are as harmless as claimed.
Some of the possible benefits of fish oil that appeared in early studies of the supplement seem to have vanished. Along with the difficulty of isolating the effects of a single nutrient, it’s possible that those early studies had small sample sizes, or participants who were truly deficient in the nutrient. Since then, long-term studies have revealed potential harms from taking fish oil unnecessarily.
Fish oil supplements contain several vitamins and two significant omega-3 fatty acids, called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While these nutrients are important, like many vitamins, many people get sufficient amounts from diet. These fatty acids are found in a number of fish, so it is often recommended to get proper doses by eating oily fish twice a week.
Additionally, the amount of these fatty acids in a supplement can vary, so it is important to check the label. There are risks and benefits to the supplements, so it’s important to speak with your physician when deciding whether you are likely to benefit from taking them.
1. Heart health
When it comes to heart disease, eating fish is recommended as a heart-healthy protein, to substitute in place of red meat.
There is strong evidence for the potential of fish oil supplements to help in lowering triglycerides, which are associated with heart disease, as well as to lower the risk of heart attack.
But although fish oil supplements may have benefits for people at risk of heart problems, their benefit has been strongly questioned for healthy people, as high levels of omega-3 intake been linked with increased risk for stroke. High levels may also interfere with some medications, such as blood thinners, according to the National Institutes of Health.
2. Brain health
The omega-3 fatty acid DHA is found in both the gray and white matter of the brain, and is an important nutrient in early development, which is why there have been efforts to supplement child foods with it, whether it be the mother who breast-feeds or infant formula.
But taking DHA supplements has not shown clear benefits at the other end of life, where studies have been done to see if the compound may help people maintain cognitive function as they age. Although a few studies have shown benefits in reaching certain endpoints, such as maintaining brain size, there has not been a demonstration that DHA accomplishes the overall goal of helping prevent Alzheimer’s.
A June 2012 study published by the Cochrane Collaboration, a group that looks at the studies done on a topic to help make decisions for medical practitioners, found no benefit from fish oil supplements for cognitively healthy older people, but the authors said longer studies would be necessary to come to a firmer conclusion.
3. Autoimmune disease
DHA has long been studied in relation to immune function. As far back as the 1970s, the compound was found to play a role in the immune system and it was thought to possibly benefit patients with autoimmune diseases, such as multiple sclerosis, in which the immune system is overactive. Since then, DHA has been tested in people with other autoimmune diseases, such as rheumatoid arthritis.