Heart Health Research Highlights
Research indicates that consuming grapes, as part of a healthy diet and lifestyle, contributes to heart health. The studies below looked at the impact of table grapes on heart health, and contribute to the mounting evidence supporting the role of grapes in heart health. Good science involves repetition of studies and their results, of course, and additional studies will be important.
In each of the studies cited below, the researchers used whole grape powder made solely from whole fresh grapes – a mix of red, green, and black varieties – that were ground and freeze-dried. Using the grape powder allows for year-round study of grapes by researchers. The whole grape powder is a substitute for whole fresh grapes.
Grape consumption significantly reduced cholesterols and bile acids in healthy subjects.1
In a four-week human study, healthy subjects consumed grape powder equal to1.5 cups of grapes per day. As a result, researchers observed a significant decrease in blood cholesterols including total cholesterol by 6.1%, HDL cholesterol by 7.6%, and LDL cholesterol by 5.9%. Bile acids, which are linked to cholesterol metabolism, were decreased by 40.9%.
In a follow up analysis2 that examined the mechanism for the cholesterol reduction, researchers found that grapes significantly reduced lathosterol, a precursor to cholesterol synthesis. Grapes also decreased the plasma cholesterol oxidation product known as 27-hydroxycholesterol.
Grape consumption helped improve antioxidant capacity and blood vessel function in healthy men.3
In this small human study, consuming grape powder in an amount equivalent to 1 1/4 cups of fresh grapes per day helped improve blood vessel function in five healthy adult male subjects. Consuming the same amount of grape powder, but twice a day for 21 days, caused even greater improvements in blood vessel function and antioxidant capacity.
Grape consumption helped reduce certain risk factors for heart disease and oxidative stress.4, 5, 6, 7
Pre- and post-menopausal women consuming the equivalent of 1 1/4 cups of grapes per day saw the reduction of key risk factors for coronary heart disease. These included a reduction in blood triglyceride levels, LDL cholesterol levels, and key markers for inflammation in the body. Additionally, the researchers observed a significant reduction in whole body oxidative stress.
In a study of men with metabolic syndrome, adding grapes to the diet helped improve vascular function by promoting relaxation of the arteries, reducing blood pressure, and a marker of inflammation.
An animal study showed that a grape-enriched diet helped prevent the accumulation of harmful oxidized cholesterol and inhibited the development of atherosclerotic lesions. Specifically, the animals consuming the grape-enriched diet exhibited reduced oxidative stress, increased serum antioxidant capacity, reduced cell uptake of oxidized cholesterol, and decreased oxidation of LDL cholesterol.
Another animal study found that adding grapes to the diet lowered the concentration of cholesterol in the aorta and also lowered plasma triglycerides and VLDL cholesterol.
Grapes added to the diet helped lower blood pressure, improve heart function, reduce inflammation and reduce heart muscle damage associated with a high-salt diet.8, 9, 10
In a series of animal studies, a grape-enriched diet helped protect against high blood pressure and the development of heart failure commonly associated with a high-salt diet. One study examined the impact of adding grapes to the diet of animals consuming either a high- or low-salt diet and also those receiving a mild dose of a common blood pressure drug, hydrazine. Those consuming a grape-enriched diet had lower blood pressure, better heart function, reduced inflammation throughout their bodies, and fewer signs of heart muscle damage than those consuming the same diet but without grapes. The group receiving the blood pressure medicine but no grapes saw a reduction in blood pressure, but their hearts were not protected from damage as they were in the grape-fed group. Two additional studies, using a similar study model and feeding a grape-enriched diet, also demonstrated these types of protective effects.
Consuming grapes increased antioxidant capacity in humans and helped prevent the damaging effects of post-meal oxidative stress.11, 12
Consuming grapes with a high fat meal helped prevent the damaging impact (reduced blood flow) that was observed with a high fat meal consumed without grapes.
In another human study, grape consumption increased blood antioxidant capacity and helped prevent post-meal oxidative stress, a natural state of oxidative stress in the body that results from eating a meal containing just protein, carbohydrates, and fat, with no antioxidants.
1.Hu, W., Zheng, R., Feng, Y., Tan, D., Chung-Tsing, G.C., Su, X., and Kim, J.E. (2023). Impacts of regular consumption of grapes on macular pigment accumulation in Singapore older adults: a randomized, controlled trial. Food Funct. 14, 8321-8330. doi: 10.1039/d3fo02105j
2. Liu, X., Yu, Y., Garcia, L.A., Au, M.L., Tran, M., Zhang, J., Lou, A., Liu, Y., & Wu, H. (2024). A grape-supplemented diet prevented ultraviolet (UV) radiation-induced cataract by regulating Nrf2 and XIAP pathways. The Journal of Nutritional Biochemistry, doi.org/10.1016/j.jnutbio.2024.109636
3. Chaves A.A., Joshi, M.S., Coyle, C.M., Brady, J.E., Dech, S.J., Schanbacher, B.L., Baliga, R., Basuray, A., & Bauer, J.A. (2009). Vasoprotective endothelial effects of a standardized grape product in humans. Vascular Pharmacology, 50, 20-26. doi: 10.1016/j.vph.2008.08.004
4. Zern, T.L., Wood, J.R., Greene, C., West, K.L., Liu, Y., Aggarwal, D., Shachter, N.S., & Fernandez, M.L. (2005). Grape polyphenols exert a cardioprotective effect in pre- and post-menopausal women by lowering plasma lipids and reducing oxidative stress. Journal of Nutrition, 135, 1911. doi.org/10.1093/jn/135.8.1911
5. Barona, J., Aristizabal, J.D., Blesso, C.N., Volek, J.S., and Fernandez, M.L. (2012, July). Grape polyphenols reduce blood pressure and increase flow-mediated vasodilation in men with metabolic syndrome. Journal of Nutrition, 1-7. doi: 10.3945/jn.112.162743.
6. Fuhrman, B., Volkova, N., Coleman, R., & Aviram, M. (2005, May). Grape powder polyphenols attenuate atherosclerosis development in apolipoprotein e deficient mice and reduce macrophage atherogenicity. Journal of Nutrition, 135, 722-728. doi.org/10.1093/jn/135.4.722
7. Zern, T.L., West, K.L., & Fernandez, M.L. (2003) Grape polyphenols decrease plasma triglycerides and cholesterol accumulation in the aorta of ovariectomized guinea pigs. Journal of Nutrition, 133, 2268-2272. doi: 10.1093/jn/133.7.2268
8. Seymour, E.M., Singer, A.A.M., Bennink, M.R., Parikh, R.V., Kirakosyan, A., Kaufman, P.B., & Bolling, S.F. (2008). Chronic intake of a phytochemical-enriched diet reduced cardiac fibrosis and diastolic dysfunction caused by prolonged salt-sensitive hypertension. Journal of Gerontology: Biological Sciences, Vol. 63A, No. 10, 1034-1042. doi:10.1093/gerona/63.10.1034
9. Seymour, E.M., Singer, A.A.M., Kirakosyan, A., Kaufman, P.B., & Bolling, S.F. (2009). Grape intake reduces heart failure pathogenesis in rats. Acta Horticulturae, 841, 207-213.
10. Seymour, E.M., Bennink, M.R., Watts, S.W., & Bolling, S.F. (2010, May). Whole grape intake impacts cardiac peroxisome proliferator-activated receptor and nuclear factor kB activity and cytokine expression in rats with diastolic dysfunction. Hypertension, Vol.55, No. 5. doi: 10.1161/HYPERTENSIONAHA.109.149393
11. Chaves A.A., Joshi, M.S., Coyle, C.M., Brady, J.E., Dech, S.J., Schanbacher, B.L., Baliga, R., Basuray, A., & Bauer, J.A. (2009). Vasoprotective endothelial effects of a standardized grape product in humans. Vascular Pharmacology, 50: 20-26. doi: 10.1016/j.vph.2008.08.004
12. Prior, R.L., Gu, L., Wu, X., Jacob, R.A., Sotoudeh, G., Kader, A.A., & Cook, R.A. (2007). Plasma antioxidant capacity changes following a meal as a measure of the ability of a food to alter in vivo antioxidant status. Journal of the American College of Nutrition, 26, No. 2, 170-181. doi: 10.1080/07315724.2007.10719599.
