Two recent studies have found that eating or supplementing with Grapes may help people struggling with obesity or those at risk of metabolic conditions.
The University of North Carolina carried out the studies and looked into grape polyphenols and their ability to impact weight gain, insulin resistance, markers of inflammation and gut microbiota.
The believed that Grapes may offer a dietary strategy for those struggling with obesity or those at risk of metabolic conditions
The first study found that participants eating butter (33% of energy from fat) combined with grapes for 11 weeks had a lower percentage of overall body fat.
This finding was attributed to increases in some beneficial bacteria, decreases in some less desirable bacterial strains, increases in microbial diversity and improved gut barrier function.
The second study used butter with an even higher fat content (44% of energy from fat), which was supplemented with lard, beef tallow, and shortening to mimic a Western-type diet.
This high-fat diet was then combined with either the polyphenol fraction of grapes or the non-polyphenol portion of grapes, as well as whole grapes.
Results from the second study showed a high-fat diet, combined with grape polyphenols, reduced the markers of inflammation in the liver
Results here showed that the high-fat diet, combined with grape polyphenols, lowered body fat percentage, markers of inflammation in the liver, and improved glucose tolerance and intestinal barrier function over a 16 week period.
While the 5% whole grape diet did not improve the metabolic profile in this study, it did increase microbial diversity and decreased abundance of several harmful bacteria in the intestinal tract.
The second study attempted to replicate a diet that is typical of the USA.
Researchers pointed towards the antiobesity and antidiabetic effects of anthocyanins which have been reported to exert these effects in vitro and in some instances in vivo.
One study identified anthocyanins from black soybeans reversed weight gain, reduced the levels of serum TG and cholesterol and increased the levels of high-density lipoproteins
Likewise, beneficial improvements in glucose tolerance were observed with supplementation of anthocyanins from maqui berry in high fat-fed mice
Source: The Journal of Nutritional Biochemistry (Published online ahead of print)
Title: A polyphenol-rich fraction obtained from table grapes decreases adiposity, insulin resistance and markers of inflammation and impacts gut microbiota in high-fat-fed mice.
Authors: Brian Collins et al.