Maybe so. New research suggests that grapes can help reduce the symptoms of heart failure associated with chronic high blood pressure, at least in rats. Researchers at the University of Michigan Health System found that the grapes benefited the animals' cardiac physiology by influencing the activities of genes and metabolic pathways that boost levels of glutathione, the most abundant cellular antioxidant in the heart. The Michigan researchers fed rats that were hypertensive and prone to heart failure a grape-enriched diet. After 18 weeks, they found that the grape consumption reduced the occurrence of heart muscle enlargement and fibrosis, decreased the formation of excess fibrous connective tissue, and improved the heart’s diastolic function. Heart failure stemming from chronic hypertension can result in an enlarged heart muscle that becomes thick and rigid (fibrosis), and unable to fill with blood properly (diastolic dysfunction) or pump blood effectively, the researchers explained. Grapes are a good source of antioxidants and other polyphenols, which the investigators credited with their beneficial effects on the heart. The study was published online on March 25, 2013 by The Journal of Nutritional Biochemistry.
E. Mitchell Seymour et al, “Diet-relevant phytochemical intake affects the cardiac AhR and nrf2 transcriptome and reduces heart failure in hypertensive rats,” The Journal of Nutritional Biochemistry, http://dx.doi.org/10.1016/j.jnutbio.2013.01.008