Recently, I mentioned that medical evidence is lacking as to whether fish oil has medical benefit (see here). A study published today in the Journal of the American Medical Association (JAMA) confirms data I had cited from the New England Journal of Medicine: fish oil does not appear to provide cardiovascular benefits.
The JAMA study is a meta-analysis – a pooled analysis of multiple smaller trials which should allow scientists to identify even small benefits with a high level of accuracy. In total, this analysis looked at data from 68,680 patients. Even with a patient pool this large, taking fish oil did not show a benefit on cardiovascular outcomes. There was no reduction in myocardial infarction (heart attacks) and no benefit on mortality.
Importantly, the study also looked at benefits (or lack thereof) according to the amount of lowering of triglyceride levels (triglycerides are harmful fats, somewhat analogous to LDL cholesterol). Fish oil lowers triglyceride levels. This is the reason why it had been expected to be beneficial. The JAMA study found that higher doses of fish oil did not influence the conclusion.
Unfortunately, there is no party marketing to doctors that they should not use certain products. Pharmaceutical companies that sell fish oil will continue to market these drugs. There is a lot of information for doctors to absorb in order to stay current. As I forecast the future, I expect that the use of fish oil is unlikely to change much (current US sales are approximately $1 billion per year). Based on the medical evidence that exists today, that’s a shame.