The participants were assigned to drink either purple Concord grape juice or a placebo beverage for 14 days. Afterward, they abstained from both drinks for 14 days. Finally, they repeated the test using whichever drink they hadn't already tried.
"Good" HDL levels "significantly increased" in participants when they drank grape juice, write the researchers.
Grape juice drinkers had HDL levels of 50 mg/dL, compared with almost 45 mg/dL in the placebo group. An HDL level below 40 mg/dL is considered a risk factor for heart disease.
The grape juice group also had lower levels of two indicators of inflammation: superoxide and soluble CD40 ligand. Inflammation plays a key role in atherosclerosis, or hardening of the arteries.
Soluble CD40 ligand is thought to contribute to the development of atherosclerosis and vascular inflammation, says Freedman in a news release.
The results suggest that alcohol-free grape juice might provide some of the cardiovascular benefits seen in studies of wine.
