A fermented bilberry extract out-performed a standard extract, leasing the French researchers to suggest that yeast fermentation produces new bioactive compounds with heart health effects.
The research team was led by Aurelie Mauray, now with France’s Institut National de la Research Agronomique (INRA), but formerly with Ferlux, which also sponsored the research. The study used the company's Extracyan bilberry product.
The team used apolipoprotein-E-deficient mice, putting the animals at an increased risk of heart disease. Apolipoprotein-E (Apo-E) is essential for the normal breakdown of triglyceride-rich lipoprotein constituents.
“The yeast-fermented bilberries extract exerts more effective antiatherogenic activity in vivo than the anthocyanin-rich bilberry extract, suggesting that fermentation generates some newcompoundswith improved health-promoting properties as compared to the anthocyaninrich standardized extract,” report the researchers in the Journal of Agricultural and Food Chemistry.
However, being a study in animals the researchers stressed that more studies are necessary to “identify the compounds responsible for these effects and to investigate possible mechanisms underlying such effects”.
Atherosclerosis, or hardening of the arteries, is a major risk factor for cardiovascular disease (CVD), which causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy about €169bn ($202bn) per year.
Mauray and her co-workers divided the mice into three groups. All groups were fed the standard control diet, but two groups received one of two bilberry extracts: One rich in anthocyanins extracted from untreated bilberries, and a second one extracted from yeast-fermented bilberries at a level of 0.02 per cent. Such an intake corresponds to about 30 mg of anthocyanidins per day in humans, said the researchers.
At the end of 16 weeks of study, significant inhibition of the development of plaques associated with atherosclerosis was observed in both bilberry groups.
“The lesion area was decreased by 15 per cent in the [untreated bilberry extract] group and by 36 per cent in the yeast-fermented bilberry-extract group compared to the control group,” report the researchers. “Additionally, mice fed the yeast-fermented bilberry-extract supplemented diet showed a 25 per cent higher reduction of the lesion area compared to the [untreated bilberry extract] group,” they added.
Mauray and her co-workers note that the active compounds in the fermented extract have yet to be identified, but suggested they may be anthocyanin-derived polymeric pigments.
Bilberries are closely related to the North American blueberry but contain a very distinct anthocyanin profile. Bilberry extracts are relatively expensive. Concerns are rife within the industry of lower-price extracts reported to be mixed with mulberry or black bean skins or azo-dyes.
Concerns were raised last year when Australian scientists discovered that azo dyes were used to mimic the colour of bilberries in a commercial product (J. Agric. Food Chem 2006, Vol. 54, Issue 19, pp. 7378 -7382). This has since expanded to reports of mulberry or black bean skins being used to increase the anthocyanin content of the extracts.
The anthocyanins content is used as the standard for bilberry, and UV spectrometry is needed to verify the 25 per cent anthocyanins. However, according to unconfirmed reports, this has led to extracts masquerading as bilberry but actually containing mulberry (22-24 per cent), or black bean skin (20 per cent).
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, doi: 10.1021/jf9035468
“ Atheroprotective Effects of Bilberry Extracts in Apo E-Deficient Mice”
Authors: Aurelie Mauray, D. Milenkovic, C. Besson, N. Caccia, C. Morand, F. Michel, A. Mazur, A. Scalbert, C. Felgines