Recent Reports on Fish Oil: Should You Stop Taking It?
Occasionally, the news media can add to my daily work load as a medical doctor. Research studies are reported that seem to counter the medical status quo. Sometimes, these reports are legitimate, but mostly they create an unfounded frenzy of worry and confusion. One recent study suggested that there was no benefit in taking fish oil supplements to prevent heart disease. Is this the new standard? Should people stop taking fish oil based on these findings?
Last month, the results of a 10-year large-scale study on fish oil were published in The New England Journal of Medicine. The research enrolled 12,000 people who were considered "high risk" for heart disease without actually having the condition. 60% of those enrolled had diabetes and 70% had high cholesterol, both significant heart disease risk factors. No participants had suffered a heart attack, however. Subjects were randomized to take 1 gram of fish oil or a placebo of olive oil. In the end, there was no difference between the fish oil and the olive oil placebo.
Yes, this was the conclusion based on a study performed on thousands of people and reported in one of the most prestigious medical journals in the world. A few important points need to be made, though.
- The fish oil dose was 1 gram. It's been widely shown in other studies that a higher dose of fish oil is needed to attain a lowering affect on triglycerides and lower inflammatory markers in the blood. Both of these factors are associated with heart disease. It is generally recommended that a person try to attain a daily dose of 4 grams taken either as one dose or dosed through the day. With store-bought fish oil supplements, it is sometimes difficult to know exactly how much omega-3 is present. And, while the prescription supplement Lovaza has the assurance that 1 gram of omega-3 is present per capsule (and a lot of the "fishiness" has been refined out), it is quite a bit more expensive. I have patients shop for store-bought fish oil, trying to get to around 4 total grams per day, reserving the prescription for those who cannot tolerate it due to a fishy after taste or upset stomach.
- Olive oil is not a placebo. It's well known that the Mediterranean Diet, which is rich in olive oil, confers a lower heart disease risk. So, comparing fish oil to olive oil and saying that there is no difference in reduction in heart disease leaves open the possibility that perhaps they both work.
- Many other studies show the benefit fish oil in cardiovascular risk and a whole host of other issues. Well-done studies preceding this one brought interest to fish oil as a therapeutic option for heart disease prevention. It is well known, as mentioned above, that fish oil reduces triglycerides and inflammatory markers. Fish oil also has a thinning affect on the blood due to some effects on the platelets in the blood. Other studies have shown that fish oil helps with depression, cognition (memory), anxiety, and dry eye syndrome. Granted, none of these are large, landmark, "defining" studies.
There are a lot of mixed messages out there regarding fish oil. I would watch the horizon for further research which will likely delineate things more conclusively. In particular, watch for the results of a trial called VITAL (Vitamin D and Omega-3 Trial) out of Harvard. This study is nationwide with over 20,000 subjects of normal heart risk and will look at prevention of the things which fish oil (and vitamin D) is touted to prevent.
Fish oil is not harmful to our bodies, and science has some mixed messages about a whole host of potential benefits. If you want to play it cautious, stay tuned for more delineating evidence on exactly what benefits are out there. If you don't want to miss the boat, and don't mind taking the fish oil capsules, do so. Make sure you are getting around 4 grams per day. Still, don't forget that putting fish into your diet is another healthy way to get those omega-3's, in addition to a nice source of protein!
And when you hear about science "revelations" on the news, appreciate that it is often part of a "honing" process, as just part of the big picture, which may, or may not, be pertinent.
Omega-3: Fishing Out the Recent Evidence. Medscape. Jun 04, 2013.