Flax seeds: virtues of omega-3 of plant origin?

April 5, 2006 – Omega-3s in flax seeds are believed to reduce the risk of atherosclerosis and regulate heart rhythms, at least in laboratory animals.

This is what Grant N. Pierce, director of research at the Saint-Boniface General Hospital Research Center in Manitoba, said during a conference given to students from the University of Montreal.

These benefits have been observed in laboratory tests first on rabbits and then on mice. In rabbits, a diet supplemented with flax seeds increased the blood level of vegetable omega-3s, alpha-linolenic acids (ALA), by up to 12%. The arteries of rabbits fed flaxseed showed less accumulation of cholesterol, responsible for atherosclerosis. This is a precursor of cardiovascular disorders and cerebrovascular accidents (CVA). The hearts of these rabbits also had less arrhythmia than those of the others.

In mice, flaxseed also reduced signs of atherosclerosis, under similar clinical conditions.

If the mechanism remains imprecise, Grant N. Pierce considers that the benefits obtained are attributable to ALA, and not to eicosapentanoic acids (EPA) or docosahexanoic acids (DHA), omega-3 found in fatty fish. This is because the rabbit body did not convert ALA to EPA or DHA during the study. In mice, there was only a modest conversion of ALA to EPA.

“ALA appears to be as effective as the other two types of omega-3s and its action may lie in lowering cholesterol or lowering inflammation,” said Grant N. Pierce.

The researcher also conducted a clinical trial with 30 healthy people. According to him, the preliminary results are full of promise. After incorporating 30 g of flaxseed (between three and four tablespoons) per day into their diet, study participants saw their blood ALA levels rise rapidly: at four weeks, they were as high as ‘after three months.

The nutrients in flax seed oil were better absorbed by the body than ground seeds and whole seeds. “Flaxseed and its oil have an advantage over fish,” said Grant N. Pierce. In addition to omega-3s, they contain fiber and phytoestrogens. “

Encouraging, but …

Asked to comment on the research of Grant N. Pierce, D^D Sylvie Dodin¹ from Laval University in Quebec, which itself has done studies on flaxseed, has been cautious. “These results are encouraging, but we do not yet know whether they are transferable to humans,” she said.

In a recent article she published², D^D Sylvie Dodin revealed that a diet supplemented with flax seeds had produced, after 12 months, no change in the blood lipid levels of a hundred healthy postmenopausal women. “I do not question the results of Mr. Pierce, but we must see what the effects will be in humans, and with what doses,” she tempers.

So far, studies with flax seeds indicate that their effectiveness is considered uncertain in slightly reducing blood cholesterol levels and preventing cardiovascular disorders.

Martin LaSalle – PasseportSanté.net

1. Dr Sylvie Dodin holds the Lucie and André Chagnon Chair for teaching an integrated approach to prevention, at Laval University, in Quebec.
2. Dodin S, Lemay A, Jacques H, et al. The effects of flaxseed dietary supplement on lipid profile, bone mineral density, and symptoms in menopausal women: a randomized, double-blind, wheat germ placebo-controlled clinical trial, Journal of Clinical Endocrinology & Metabolism, March 2005, Vol. 90, N^o 3, 1390-7.