Omega-3 fats found in oily fish (like salmon, trout, mackerel and herring) are often said to help protect against cardiovascular disease (e.g. heart attacks and strokes). However, a recent review of the evidence points out that while earlier studies found that giving individuals omega-3 fats had protective effects, more recent studies have not. The authors of this study then set about examining the possible reasons for this disparity.
One potential explanation they offer is related to the fact that omega-3 fats are most likely to be beneficial to those who are deficient in these nutrients. The suggestion here is that, previously, populations tended to be on the deficient side. However, with the increasing promotion of omega-3 fats recently, more and more people have been consuming more of these fats in their diet or taking them in supplement form, resulting in less deficiency as a whole. The less deficient a population is, the less likely they are to benefit from additional supplementation of omega-3 fats. The use of people in trials who tend not to be deficient in omega-3 fats may therefore explain the negative results seen in more recent studies.
The authors of the study offer another potential explanation for the recent negative findings. This concerns a possible interaction between omega-3 fats and cholesterol-lowering statin drugs. The authors cite three main studies in which omega-3 supplements were given to individuals who may also have been taking a statin.
In one of these studies, in those taking statins, rates of complications of cardiovascular disease were 13 per cent in individuals taking omega-3 supplements compared with 15 per cent in those not taking these supplements.
However, in those not taking statins, the rates of complications were 9 per cent and 18 per cent, respectively. The difference in these results was not statistically significant, but this might have had something to do with factors such as small study size. Overall, there is a suggestion here that statins may nullify the effects of omega-3, which is an idea put forward by the authors of this study themselves.
The authors of the review then go on to suggest mechanisms through which omega-3 fats and statins may interact. For example, they point out that statins promote the metabolism of omega-6’s fats (such as arachidonic acid) which antagonise the effects of omega-3 fats. Omega-6 fats tend to be inflammatory in nature and therefore counteract the known anti-inflammatory effects of omega-3 fats (inflammation has emerged as a potent underlying cause of cardiovascular disease).
All drugs have potential upsides and downsides. This latest review draws our attention to a potential downside of statins, namely their ability to disrupt the anti-inflammatory properties of heart-healthy omega-3 fats. On the plus side for statins, they are inherently anti-inflammatory themselves. In fact, some believe that whatever benefits they have has a lot to do with this property, and little to do with the impact they have on cholesterol.
When it comes to inflammation, it seems statins give with one hand but take with the other. This may explain why, overall, they do about as much harm as good.
To find out how Omega 3 Fats can benefit your heart, click here:
Here’s to a healthy heart
Dr John Briffa
for The Cholesterol Truth
Bear in mind we are not addressing anyone’s personal situation and you should rely on this for informational purposes only. Please consult with your own physician before acting on any recommendations contained herein.
1. de Lorgeril M, et al. Recent findings on the health effects of omega-3 fatty acids and statins, and their interactions: do statins inhibit omega-3? BMC Medicine 2013, 11:5 doi:10.1186/1741-7015-11-5
2. Kromhout D, et al. Alpha Omega Trial Group: n-3 fatty acids and cardiovascular events after myocardial infarction. N Engl J Med 2010;363:2015-2026.
3. Eussen SR, et al. Effects of n-3 fatty acids on major cardiovascular events in statin users and nonusers with a history of myocardial infarction. Eur Heart J 2012;33:1582-1588