By Stephen Daniells, 06-Feb-2009
Women with increased intake of lignans, and subsequently levels of
metabolites in the blood, tend to have lower BMIs and total body fat mass,
says a new study from Canada.
A study of 115 post-menopausal women showed that those with the highest
blood levels of enterolactone, a lignan metabolite, had a BMI 4 kg/m2 less
than women with the lowest average blood levels, according to results
published online ahead of print in the British Journal of Nutrition.
Moreover, the highest blood levels of enterolactone were also associated
with 8.5 kg less body fat, compared to women with the lowest levels, report
researchers from Laval University in Quebec.
While the study does not show establish a causal link between lignans and
the women's metabolic profile, the research does add to the list of
potential health benefits of the plant compounds.
Plant lignans, from sources such as flax seed,
whole grain cereals, berries, vegetables and fruits, are metabolised in the
colon by microflora into enterodiol and enterolactone. Previous research
has focussed on plant lignans as reducing the risk of prostate cancer, and
in improving menopause health.
The main lignan from flaxseed is secoisolariciresinol diglucoside (SDG),
which is metabolised to give enterodiol and enterolactone. These two
metabolites are then absorbed from the gut and transported to the liver
where they undergo further reactions before entering circulation.
SDG-containing products are well-represented on the market, including
Melrose Health's Lignan Life.
The researchers, led by André Tchernof, evaluated the intake of lignans
using a three-day dietary record. The 115 women (average age of 56.8) also
had blood taken to evaluate blood levels of enterolactone.
High intake of lignans was associated with lower body fat mass and BMI,
compared to women with the lowest average intakes. Moreover, women with the
highest average blood levels of enterolactone had improved glucose disposal
rates (8.3 versus 5.5) and significantly lower blood glucose levels,
compared to women with the lowest average blood levels.
"In conclusion, women with the highest enterolactone concentrations had a
better metabolic profile including higher insulin sensitivity and lower
adiposity measures," wrote the researchers.
A number of studies have reported links between increased dietary lignan
intake, and/or increased levels of enterolactone and/or enterodiol and
protection/ reduced risk of a wide range of conditions, most notably breast
cancer, prostate cancer, and reduced hair loss. Clearly, more research is
needed to evaluate the potential role, and to determine causality, for the
potential role of lignans and their metabolites for metabolic profiles.
Source: British Journal of Nutrition
Anne-Sophie Morisset, Simone Lemieux, Alain Veilleux, Jean Bergeron, S.
John Weisnagel and André Tchernof Impact of a lignan-rich diet on adiposity
and insulin sensitivity in post-menopausal women. British Journal of
Nutrition, Published online by Cambridge University Press 13 Jan 2009