Grape seed flour’s metabolic benefits linked to gut changes: Study
The grape seed flour was associated with a significant reduction in the ratio of Firmicutes to Bacteroidetes in Golden Syrian hamsters fed a high-fat, report scientists from UC Davis, Konkuk University (Korea), and Sonomaceuticals LLC/WholeVine Products. The Firmicutes/Bacteroidetes ratio is a good biomarker for obesity.
The Chardonnay grape seed flour was also associated with prevention of LDL- and total-cholesterol increases, as well as prevention of abdominal fat tissue weight gain and body weight gain, according to results published in the Journal of Agricultural and Food Chemistry.
On the flip side, populations of Bifidobacterium spp. and Lactobacillus spp were lower in the hamsters fed the high-fat diets supplemented with the Chardonnay grape seed flour.
“[A]lthough our study did not provide evidence for direct interaction of Chardonnay grape seed flour with intestinal microbiota, these findings suggest that the effect of Chardonnay grape seed flour on ameliorating high fat- and high cholesterol-induced metabolic disorders is closely linked to modulation of intestinal microbiota,” wrote the researchers, led by Hyunsook Kim.
The authors stressed that the results should be “considered cautiously because only a few species and genera were quantified”.
“In-depth analysis of intestinal microbiota composition following consumption of Chardonnay grape seed flour warrants further investigation.”
Gut health and obesity
The study adds to emerging body of science supporting the effects of gut microflora on metabolic factors and obesity.
A 2005 study by Jeffrey Gordon and his group at Washington University in St. Louis indicated that obese mice had lower levels of Bacteroidetes and higher levels of Firmicutes, compared with lean mice.
One year later and Dr Gordon’s reported similar findings in humans: The microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person, suggesting that obesity may have a microbial component (Nature, Vol. 444, pp. 1022-1023, 1027-1031).
A more recent paper from the same group in Science Translational Medicine (Vol. 3, 106ra106) reported that ingestion of probiotic bacteria produced a change in many metabolic pathways, particularly those related to carbohydrate metabolism.
The new study, albeit limited, suggests a role for flavonoids to alter bacterial populations in the gut and influence metabolic processes.
The researchers divided male Golden Syrian hamsters into three groups. All the groups were fed a high-fat diet, and two groups received additional grape seed flours from either Chardonnay or Cabernet Sauvignon for three weeks. Both grape seed flours were provided by Sonomaceuticals, LLC/WholeVine Products.
Results showed that fecal levels of Bifidobacterium spp., Lactobacillus spp., and Firmicutes significantly decreased in the Chardonnay group, compared with to control, while Bacteroides fragilis increased.
Enterobacteriaceae levels in feces decreased in the Cabernet group, compared with the control diet.
The decrease in Lactobacillus spp. in the Chardonnay group was accompanied by an effect on hepatic bile acid metabolism and improved plasma cholesterol concentrations, said the researchers.
“Quantification of selected species/genera and phylum of fecal bacteria from obese and hypercholesterolemic hamsters revealed that supplementation of flavonoid-rich Chardonnay grape seed flour significantly altered intestinal microbiota composition and total number,” wrote the researchers.
“The present study provides further indirect evidence for the potential role of the intestinal microbiota in metabolic dyslipidemia.”
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, Article ASAP, doi: 10.1021/jf5026373
“Modulation of the Intestinal Microbiota Is Associated with Lower Plasma Cholesterol and Weight Gain in Hamsters Fed Chardonnay Grape Seed Flour”
Authors: H. Kim, D.H. Kim, K.H. Seo, et al.