ARS scientists have teamed up with WholeVine Products, a maker of a variety of wine grape seed flours, cookies and crackers made with the flours, as well as grape seed oil. They have shown that Chardonnay grape seed flours reduce cholesterol and weight gain and modify gut bacteria in animal models of obesity.Photo credit: Peggy GrebA U.S. Department of Agriculture (USDA) scientist is investigating the potential health benefits of specialty flours-particularly those made from wine grape seeds.

Working with WholeVine Products, a Sonoma, California, company that makes wine grape flours, Agricultural Research Service (ARS) chemist Wallace Yokoyama found that hamsters fed diets similar in caloric content to the American diet mixed with Chardonnay white wine grape seeds had reduced blood cholesterol, hepatic steatosis—also known as "fatty liver"—and weight gain compared to hamsters fed diets without grape seeds or Cabernet Sauvignon or Syrah red grape seed flour. According Yokoyama, hamsters were used in these preliminary laboratory experiments, because they absorb cholesterol from food, and synthesize it in the liver, in much the same way as humans.

Although earlier research by other scientists has shown cholesterol-lowering and weight-control effects from highly purified extracts of winemaking byproducts, this ARS study is the first to show that flour milled from whole grape seeds, with a little of their natural oil, is able to reduce blood cholesterol levels.

Yokoyama and his team also examined changes in the activity of some of the genes associated with obesity. They found that leptin, which is usually high in people who are obese, decreased. Adiponectin, which is believed to help prevent diabetes and atherosclerosis, increased.

Other grape seed research underway involves looking at the effect of grape seed flour and bacteria living in the animal's gut. Yokoyama and his colleagues are adding Chardonnay grape seed flour to rations fed to laboratory mice to find out if this changes the kinds and amounts of bacteria dwelling in their gut. This research is important because some gut bacteria may be beneficial in controlling obesity or reducing risk of type 2 diabetes, according to Yokoyama.

ARS and its collaborator, WholeVine Products, have applied for a patent for their grape seed flour discoveries.

ARS is USDA's principal intramural scientific research agency.

Read more about this work in the September 2015 issue of AgResearch.