Moreover, they found that the women exhibited an increase in high-density lipoprotein cholesterol, which in turn may reduce the risk of cardiovascular disease, after consuming white grape juice for 30 days.
Suvalan, a Brazilian manufacturer of juice, supplied the white grape juice (Vitis labrusca, or ‘Fox grape’) used in the study. Suvalan markets white grape juice in Brazilian grocery channels (‘Suvalan 100% Suco Uva Branca’).
“Although studies on purple grape juice already exist, this is, to our knowledge, the first study to evaluate the effect of white grape juice supplementation in humans,” the researchers wrote in their study, published in the January 2019 edition of the journal Nutrition.
With a relatively small sample population (25) and no placebo, the authors characterized the study as a pilot. “Nevertheless, our study yielded very reproducible results that can be attributed to the supplementation,” they wrote.
“Further studies are necessary to confirm the effect of grape juice supplementation in both men and women,” they added.
Twenty-five women aged 50 to 67 participated in the study. They consumed 7 mL of the juice without other changes in diet energy consumption or habitual lifestyles over 30 days. The researchers collected body measurements and blood samples before and after the 30-day intervention period.
The researchers advised participants to not consume other grape-derived products throughout the 30-day period.
During lab visits on the first and last day of the study period, nursing technicians collected blood samples and gave out three questionnaires, which participants filled under the supervision of a dietitian. The questionnaires collected the women’s sociodemographic characteristics, diet recall, as well as body measurements.
Compared to the baseline measurements taken at the beginning of the study, the women exhibited lowered total cholesterol, driven by a lowering of LDL cholesterol though there was an increase of HDL cholesterol.
The women also exhibited a decrease in triacylglycerols, and some decreases in body mass index, waist circumference, and abdominal circumference.
Published online ahead of print, https://doi.org/10.1016/j.nut.2018.05.026
“White grape juice increases high-density lipoprotein cholesterol levels and reduces body mass index and abdominal and waist circumference in women”
Authors: Caroline Zuanazzi, et al.