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Concord Grapes in the News

Juicy New Research on Immune Health

New Study Suggests 100% Grape Juice May Play a Role in a Healthy Immune System

January 14, 2011

More than a decade’s worth of research suggests that drinking Concord grape juice may benefit the heart.1-8 While emerging research has also pointed to Concord grape polyphenols’ possible immune health benefits,9-12 for the first time, a study involving humans reinforces that grape juice made with Concord grapes and vitamin C may play a role in supporting adults’ immune system health.

To date, the emerging research on Concord grapes and immune health has involved studies using animal and cell models.9-12 This new research by University of Florida scientists, which was published in the January/February 2011 issue of the Journal of Medicinal Food, is the first study with humans and it points to the opportunity for more research on the possible immune health benefits of grape juice made with Concord grapes.13

Grape Juice and Immune Health
The conclusions drawn suggest that daily consumption of 100% grape juice made with Concord grapes and added vitamin C may help support a healthy immune system in healthy adults, though further research is needed. In their study, 85 adults between the ages of 50-75 years consumed either 12 ounces of 100% grape juice or a placebo, grape-flavored drink every day for 9 weeks. Subjects who consumed the 100% grape juice made with Concord grapes showed significantly higher numbers and increased proliferation of a specific type of immune cell, the gamma delta T-cell, compared to the placebo group. (An increase in gamma delta T-cell proliferation indicates an improved ability for these cells to be primed for action and ready to respond to potential invaders.)

The subjects who consumed the 100% grape juice made with Concord grapes and vitamin C also had significantly higher levels of serum vitamin C, which functions as an antioxidant to support a healthy immune system; maintenance of serum antioxidant capacity levels (while the antioxidant capacity of those consuming the placebo drink dropped over the study period); and significantly lower induced DNA strand breaks versus the placebo, suggesting antioxidant protection against oxidative stressors that can damage healthy cells.

It is important to note that in addition to containing polyphenols, each serving of 100% grape juice made with Concord grapes consumed in this study delivered more than 100% of the daily value for vitamin C. The observed positive effects could be the result of the vitamin C, the polyphenols, or both working together. More research is needed before any conclusions can be drawn.

Expert Outlook
According to study author Dr. Susan S. Percival of the University of Florida in Gainesville, “Plant foods contain an array of vitamins, minerals and beneficial plant nutrients (like polyphenols). And, purple plant foods, such as the Concord grape, deliver natural plant nutrients not found in many other colors of fruits and vegetables.” She added, “While this study can’t directly pinpoint a specific plant-derived nutrient responsible for the positive results seen, it further supports that a healthy diet, rich in colorful fruits and vegetables, like Concord grapes and 100% grape juice, can support a healthy immune system.”


1 Anselm E, Chataigneau M, Ndiaye M, Chataigneau T and Schini-Kerth VB. Grape juice causes endothelium-dependent relaxation via a redox-sensitive Src- and Akt-dependent activation of eNOS. Cardiovasc Res. 2007. 73(2):404-413.
2 Freedman JE, Parker C, 3rd, Li L, Perlman JA, Frei B, Ivanov V, Deak LR, Iafrati MD and Folts JD. Select flavonoids and whole juice from purple grapes inhibit platelet function and enhance nitric oxide release. Circulation. 2001. 103(23):2792-2798.
3Chou EJ, Keevil JG, Aeschlimann S, Wiebe DA, Folts JD and Stein JH. Effect of ingestion of purple grape juice on endothelial function in patients with coronary heart disease. Am J Cardiol. 2001.88(5):553-555.
4 Fitzpatrick DF, Hirschfield SL and Coffey RG. Endothelium-dependent vasorelaxing activity of wine and other grape products. Am J Physiol. 1993. 265(2):H774-H778.
5 Stein JH, Keevil JG, Wiebe DA, Aeschlimann S and Folts JD. Purple grape juice improves endothelial function and reduces the susceptibility of LDL cholesterol to oxidation in patients with coronary artery disease. Circulation. 1999. 100(10):1050-1055.
6O’Byrne DJ, Devaraj S, Grundy SM and Jialal I. Comparison of the antioxidant effects of Concord grape juice flavonoids alpha-tocopherol on markers of oxidative stress in healthy adults. Am J Clin Nutr. 2002. 76(6):1367-1374.
7Vinson JA, Yang J, Proch J and Liang X. Grape juice, but not orange juice, has in vitro, ex vivo and in vivo antioxidant properties. Journal of Medicinal Food 2000 3(4):167-171.
8 Vislocky LM and Fernandez ML. Biomedical Effects of Grape Products. Nutr Rev. 2010. 68(11):656-670.
9 Lipson SM, Cohen P, Zhou J, Burdowski A and Stotzky G. Cranberry cocktail juice, cranberry concentrates, and proanthocyanidins reduce reovirus infectivity titers in African green monkey kidney epithelial cell cultures. Molec Nutr Food Res. 2007. 51(6):752-758.
10 Ferrari C, Monge L, Zaccheo A, Gordon R, Livingston R, Stotzky G, Burdowski A and Lipson SM. Effect of store-purchased and pure cranberry and grape juice drinks on the reduction of Reoviridae infectivity titers in cell culture and cell-free suspensions. Presented at The American Society for Microbiology 109th General Meeting. Philadelphia, PA. May 17-21, 2009.
11 Leon MS, Kibrik P, Karthikeyan L, Gordon Ronald E and Lipson Steven M. Cranberry and Grape Juices Reduce Rotavirus Infectivity in Cell-Free Suspension and Maintain Tight Junction Integrity of Infected Epithelial Cells in Monolayer Culture. Presented at The American Society for Microbiology 110th General Meeting. San Diego, CA. May 23-27, 2010.
12 Lipson SM, Gordon RE, Karthikeyan L, Singh M, Burdowski A, Roy M and Stotzky G. Cranberry and Grape Juice Drinks Affect Infectivity, Integrity, and Pathology of Enteric Viruses in an Animal Model. Ch. 11. In Flavor and Health Benefits of Small Fruits. Qian MC and Rimando AM, Eds. American Chemical Society: Washington, DC.
13 Rowe CA, Nantz MP, Nieves C, West RL and Percival SS. Regular Consumption of Concord Grape Juice Benefits Human Immunity. J Med Food. 2011. 14(1-2):69-78.

Grape Research Overview

For nearly 20 years, researchers have been exploring an important mix of plant nutrients – polyphenols – found in Concord grapes and the effects they have on the body, including possible benefits in supporting cardiovascular health. In addition, emerging research is being conducted to determine whether Concord grapes play a role in supporting a healthy mind and immune system. See the research.


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An observational study, usually a retrospective study (a study that looks backward in time) that compares two groups of people: 1) those with the specific condition (e.g., disease) being studied (cases) and, 2) a similar group of people without that condition (controls). Researchers compare these two groups of people and important characteristics, such as certain lifestyle choices, to determine what factors may be associated with the condition under investigation.

A type of study that often includes patients with specific health conditions who could benefit from receiving a new treatment. These studies can also be performed in healthy subjects. The end goal of a clinical study (also called clinical research or clinical trial) is to determine effectiveness and safety of a health intervention in humans.

An observational study, usually prospective (looking forward), that follows a group of similar people over time. The goal is to determine which factors and exposures affect the development of a specific outcome or health condition (e.g., disease) during the study’s time period.

A type of observational study, often given as a survey, that examines a group of subjects during a single occasion, or over a very short period of time. This type of study aims to describe the relationship between health-related conditions (e.g., metabolic syndrome, hypertension) and other factors that exist in the general population (e.g., dietary intake, physical activity levels), during a particular time period.

A type of study in which researchers simply observe subjects and measure the associations between certain characteristics (e.g., fruit/vegetable intake) and specific outcomes (e.g., obesity). Examples of observational studies include case-control studies, cross-sectional studies, and cohort studies. While these studies gather important information, they cannot prove that a specific treatment or factor affects health.

A small scale, preliminary study that is conducted to determine the potential for a larger study.

A stage of research that often occurs prior to trials involving humans. This type of research can help determine mechanisms of action of a treatment, or how the treatment is causing the effect, as well as help ensure the safety of treatment in subsequent human trials.

In vitro
Testing performed in a controlled environment, such as a test tube or a Petri dish, instead of living organisms. In vitro literally means "within the glass" in Latin.

Ex vivo
These experiments are performed on tissue (e.g., animal or human cells) taking place outside of the organism, such as in a laboratory setting. In Latin, this means "out of the living."

In vivo
These tests are done on whole, living organisms. Technically, animal and human testing are two forms of in vivo research, which means "within the living." These experiments may be performed outside of a laboratory setting.

A study designed to provide the most credible information about the cause and effects of treatment. These types of studies are recognized as unbiased because they involve the random assignment of treatments to subjects being studied.

The tendency throughout any stage of research to generate findings that may not reflect "true values." In clinical trials, researchers try to avoid many kinds of bias, including selection by randomizing subjects, measurement by creating placebos and performing blind trials, and confounding by carefully designing the study and analyzing the findings.

Study in which subjects do not know whether they receive the treatment or the placebo, which assists in prevention of bias. Double-blinded studies are a higher level of scientific rigor because neither the participants nor the investigators know who is receiving the treatment or the placebo. A double-blind crossover study means each participant undergoes both the treatment and control scenario, typically with a wash-out period in between.

Study that allows researchers to isolate the effect size of the treatment by comparing a group given a simulated treatment (e.g., grape flavored drink) to those with the real treatment (e.g., Concord grape juice), which reduces measurement bias. The placebo should match as closely as possible to the treatment without containing the active ingredients.

Study involving participants who are randomly assigned to either the treatment or the placebo group, reducing selection bias.