This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.
What happens to seeds from wine grapes? They’re typically put in compost, mixed in cattle feed, or dumped in landfills. But this may be seen as a waste for bakers who like cooking with specialty ingredients and those of us who are looking for foods that could benefit our health.
The USDA’s Agricultural Research Service (ARS) is partnering with WholeVine Products in Sonoma, California, to explore the health benefits of unique wine grape seed flours, which can be used in breads, cookies, crackers and other goodies.
Chemist Wally Yokoyama and his colleagues at the USDA-ARS Western Regional Research Center (WRRC) in Albany, California, discovered that blood cholesterol, hepatic steatosis—known as “fatty liver”—and weight gain were reduced in laboratory hamsters fed rations mixed with flour milled from Chardonnay wine grape seeds, as compared with hamsters fed rations containing Cabernet Sauvignon or Syrah grape seed flour.
In the past, research by others has shown the effects of extract mixtures of winemaking byproducts in lowering cholesterol and controlling weight. However, “this is the first study to show that flours milled from whole grape seeds, without most of their natural oil, can reduce blood cholesterol levels, particularly the ‘bad’ LDL (low density lipoprotein) and VLDL (Very low-density lipoprotein) cholesterols,” says Yokoyama, who works in WRRC’s Healthy Processed Foods Research Unit.
Yokoyama and his team also looked at changes in the activity of genes associated with obesity—the way our bodies metabolize fats and cholesterol. “We found that leptin, a hormone produced by fat cells that is typically high in obese individuals, decreased,” Yokoyama says. “On the other hand, there was an increase in adiponectin, a protein believed to help prevent diabetes and atherosclerosis.”
In a separate study, they added Chardonnay grape seed flour to rations of mice to determine if the flour changes the kinds and amounts of bacteria dwelling in the animals’ gut. “This is important because some gut bacteria may play a beneficial role in controlling obesity or reducing the risk of type 2 diabetes,” Yokoyama says. “Our research showed a dramatic decrease in the numbers of gut bacteria, and we were able to relate some species to changes in ‘bad’ LDL cholesterol and weight gain.”
A patent application for these wine grape seed flour discoveries has been filed by ARS and WholeVine Products.