Blueberries Studied

Blueberry's Effects on Cholesterol Examined in New Laboratory Study

Laboratory hamsters that were fed rations enriched with
blueberry peels and other blueberry-juice-processing pulp
had better cholesterol health than subjects whose rations weren't enhanced with blueberries. That's according to a
study led by U.S. Department of Agriculture (USDA) researchers, at the Western Regional Research Center operated in Albany Calif., by the Agricultural Research
Service (ARS), the principal scientific research agency
of USDA.

In the investigation, the lab subjects were fed high-fat food rations. For some, those rations were supplemented with one of three different kinds of juice by-products: blueberry skins- the peels leftover when berries are pressed to make juice; fiber extracted from the peels; or natural compounds known as polyphenols, also extracted from the peels. Blueberry polyphenols give the fruit its natural purple, blue, and red coloration.

In an article published in the Journal of Agricultural and Food Chemistry in 2010, the investigators reported that all the subjects that were fed blueberry-enhanced rations had from 22 to 27 percent lower total plasma cholesterol than those fed rations that didn't contain blueberry juice by-products.

Levels of VLDL (very low density lipoprotein and considered a form of "bad" cholesterol) were about 44 percent lower in the
blueberry-fed subjects.

The researchers used a procedure known as real-time reverse transcription polymerase chain reaction, or RT-PCR, to learn about the genes responsible for these effects. This approach allowed the scientists to pinpoint differences in the level of activity of specific liver genes.

The liver makes cholesterol and also helps get rid of excessive levels of it. Results suggest that activity of some liver genes that either produce or use cholesterol resulted in the lower blood cholesterol levels.

The study is the first published account of cholesterol-lowering effects in laboratory subjects fed blueberry peels or fiber or polyphenols extracted from those peels. At this stage of investigation, the researchers don't know which berry compound or compounds activated the liver genes, or which parts of the berry have the highest levels of these compounds.


Story Source: May/June 2011 issue of Agricultural Research magazine.
Journal Reference: Journal of Agricultural and Food Chemistry, 2010;
USDA/Agricultural Research Service (2011, June 1)