Fish oil is one of the most frequently used supplements. Recent data have questioned its efficacy, as well as raised concerns about its safety.
Fish oil supplementation arose as an idea from population-based studies which found lower than expected rates of coronary heart disease in populations, such as eskimos, for a given level of serum cholesterol. Subsequent investigation in other populations showed that fatty fish in the diet seemed to be inversely correlated with lower rates of coronary disease, with higher fish consumption associated with lower rates. Mechanistic studies suggested that oils that are rich in omega-3 fatty acids, such as occur in fatty fish, may reduce triglycerides, have an anti-platelet effect, and have been hypothesized to reduce atherosclerosis. Sounds good….but do they really work?
The first and only large clinical trial, the GISSI prevention study, compared about 15,000 patients randomized to supplementation with either olive oil, or a high-quality omega-3 preparation currently available in the US as Lovaza (but not comparable to the fish oil supplements currently available over the counter). This study showed no difference in mortality, a slight decrease in the rate of sudden death, and no difference in heart attack. Fish oil therefore became incorporated into guidelines and popular use, because there were no safety concerns. However, the study was performed before the widespread use of statins. Since statins are so safe and effective, and not only reduce total and LDL cholesterol but also reduce death, stroke, heart attack, stenting, and bypass surgery, what is the role of fish oil in a person who takes statins?
Recent data, including a high-quality meta-analysis, has shown that fish oil in statin-treated groups of patients has no beneficial effect and may be associated with a slight risk of bleeding.
We would therefore make the following suggestions:
- Statins are the primary strategy for reducing risk of vascular events in both low and high risk patients
- Fish oil adds very little beneficial for patients on statins
- Because of the bleeding risk, fish oil should be avoided in patients on Coumadin, xarelto, pradaxa and eliquis, and possibly in patients on aspirin plus either Plavix, effient or brillinta
- Hi-dose fish oil (4 g of lovaza) can lower triglycerides if they are significantly elevated (> 500)
- As always, ask your cardiologist and internist about whether this drug is good for you or not
Dr. Steven Borzak