The berry contains polyphenols that interact with carbohydrates and proteins so that the rise in blood glucose is lower and slower.
Black currants help regulate blood glucose levels. Researchers from the University of Eastern Finland and the Saxony University of Applied Sciences have found that a 75 g serving of black currants is able to lower blood sugar concentration after meals (postprandial). This amount of currants is half that previous studies had determined as effective.
The study authors state that black currants flatten and lengthen the rise in blood glucose that occurs after meals. The key is in the content of polyphenolic compounds, especially anthocyanins, the pigments that give gooseberries their purple color.
GOOSEBERRY POLYPHENOLS FLATTEN THE GLUCOSE CURVE
Anthocyanins and other polyphenols slow the absorption of glucose in the small intestine by interacting with enzymes that digest carbohydrates and glucose transporting proteins. Additionally, the compounds reduce oxidative stress and inflammation.
In previous studies that had already shown the positive effect of black currants on postprandial glucose metabolism, a 150 g serving had been used. The Finnish researchers decided to investigate whether a similar effect could be achieved with half as many currants, and the result has been positive.
In the study, 26 healthy participants consumed four different test products on four separate occasions after fasting overnight. The test products were sugar water (control), black currant puree with added sugar, a black currant product on a fermented quinoa base, and the fermented quinoa base without black currants.
Blood samples were taken to analyze glucose, insulin and free fatty acid levels before fasting meals and 15, 30, 45, 60, 90, 120 and 180 minutes after consuming the products.
Compared to sugar water, both blackcurrant products induced an attenuated postprandial glycemic response, which was seen in a maximal reduction in glucose and insulin, a delayed drop in glucose levels, and a delayed increase in free fatty acids.
“Ingestion of the sugar water induced a rapid and high initial rise in glucose and insulin concentrations. Glucose concentrations rapidly fell below the fasting level and reached the lowest concentration (below the fasting level) in one hour.
These effects on glucose and insulin responses were attenuated when 75 g of black currant were consumed with the same amount of sugar. “Ingesting black currants produced a more beneficial glycemic profile,” the researchers wrote.
The researchers hope that the study results may encourage people to incorporate black currants into their diets by reducing the risk of developing obesity and diabetes.
“Black currants are very nutrient-rich berries. They are a very good addition to a healthy and balanced diet “, say the Finnish researchers. They add that as currants can taste too sour and bitter for the palate of some people, you can add some sweetener, which can even be a moderate amount of sugar, without the body’s response becoming as bad as if only sugar were consumed.
The study’s lead author, Dr. Jenni Lappi, explains that gooseberries can be taken alongside quinoa or high-fiber whole grains. Lappi will soon investigate whether blueberries have similar properties in relation to glucose levels.