March 31, 2006 – The benefits of omega-3s on heart health are questioned by British researchers in the pages of British Medical Journal1.
As part of a meta-analysis, they reviewed 89 studies conducted on the effects of these fatty acids from 1990 to 2003. Their conclusion? The effects of omega-3 against mortality, cardiovascular disorders and cancer are not evident.
The authors of the study, however, hasten to qualify their remarks. There is no question for them to advise the population to abandon the consumption of oily fish or omega-3 supplements since they are good for the health of neurons and for other cells of the body.
However, they do clarify about people with cardiovascular disease. According to them, omega-3s would offer some protection to people who have already suffered an acute myocardial infarction. This has not been shown in those who suffer from angina pectoris. Omega-3s would not protect against strokes either. They could even be harmful to people with heart rhythm problems who wear a defibrillator.
These researchers affiliated with the University of East Anglia, in Great Britain, also indicate that omega-3 does not seem to reduce the risk of developing cancer. Their impact on total mortality remains uncertain, although some of the studies reviewed seem to attribute some protective effect to them.
However, the conclusions of their study are not unanimous, some experts highlighting some weaknesses. This is the case of the omega-3 specialist, Michel Lucas, of the Lucie and André Chagnon Chair for the advancement of an integrated approach to prevention at Laval University in Quebec.
“I find it unfortunate that the Barr study, carried out in 2003, was incorporated into this meta-analysis”, underlines Michel Lucas, epidemiologist and nutritionist. The Barr study brought together about 3,000 participants and its findings cast doubts on the virtues of omega-3s. However, its methodology was so flawed that it had only been published in a second-rate medical journal. Its inclusion in this new meta-analysis could skew the conclusions the researchers drew.
Michel Lucas also regrets that the authors of the meta-analysis do not make a clear distinction between omega-3 of marine origin and those of plant origin.
So far, studies demonstrating the health benefits of omega-3s have focused on fish oils. These would help prevent heart and cardiovascular disorders, slow their progression and reduce the risk of recurrence. As for flax seeds, an important source of omega-3 from vegetable sources, their effectiveness is considered uncertain in slightly reducing blood cholesterol levels.
“I think that this study indicates above all that we need others which will be better carried out”, concludes Michel Lucas.
Jean-Benoit Legault – PasseportSanté.net
According to theFrance Media Agency.
1. Hooper L, Thompson RL, Harrison RA, et al. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review, British Medical Journal, doi: 10.1136 / bmj.38755.366331.2F, March 24, 2006.