Grape Science Center

round corners side_grapes

Immune System Health

Immune system health

We invite you to discover the emerging science behind Concord grapes. While more research is needed to confirm Concord grapes’ link to health, in this section you will find the very latest information on grape science.

Please note: The following research overviews are based on a thorough assessment of the studies, but they are intended to be summaries only. Please refer to publications in each section for further details. As always, please keep study designs and limitations in mind when assessing how this research may or may not relate to your health or the health of your clients.

Emerging research suggests that certain micronutrients and polyphenols, like those found in Concord grapes, have the potential to play a role in immune system health.1-8 Because few studies have looked at the role of grapes and immunity in humans, this area is considered very preliminary until further data is available.

  • A study by Rowe et al. of 85 healthy adults, some of which were given 360 mL of 100% grape juice made with Concord grapes, plus vitamin C, for 9 weeks vs. a placebo, found an increase in a specific type of immune cell, the gamma delta T-cell, in the grape juice group compared to the placebo group. (This type of T-cell detects potential pathogens and alerts the immune system to respond.) The study also found that, compared to the placebo group, 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, suggesting antioxidant protection against oxidative stressors that can damage healthy cells. The authors note that these observed effects could be the result of the micronutrient vitamin C, the polyphenols, or both. One theory is that gamma delta T-cells recognize and utilize the polyphenols, since their structures resemble foreign antigens.7
  • Previous in vitro experiments have examined the role that certain polyphenols that may be found in Concord grapes play in immunity. Falchetti et al. reported that resveratrol exerted a dose-dependent protective effect on peripheral human immune cells, through stimulation of two different immune T-cells (CD4+ and CD8+).9 Another in vitro and in vivo (mice) experiment by Zhang et al. in 2005 concluded that proanthocyanidins (polyphenols) from grape seed extract, in combination with doxorubicin (chemotherapeutic agent), inhibited tumor-growth by a proposed enhancement of immune function, including lymphocyte stimulation.2

Laboratory studies performed on animal and human cells also suggest that polyphenols may block or neutralize certain viruses.3,6 However, a great deal of additional research is needed before we know if grape juice will protect humans against viruses in real-life conditions.

  • In 2007 and 2010, Lipson et al. reported that both cranberry and grape juice extracts, or their purified proanthocyanidins, reduced infection of the reovirus (which is associated with gastrointestinal infection) in ex vivo animal kidney epithelial cells.3,6
  • Other researchers have found that resveratrol inhibited different viruses, specifically the polyomavirus10 and cytomegalovirus, from infecting cells.11 Evers and colleagues (2004) found that in human embryonic lung fibroblasts, resveratrol thwarted all phases of infection from cytomegalovirus.11 Similarly, Berardi et al. (2009) published findings from mice fibroblast and human tumor cell lines indicate that a dose-dependent relationship exists between resveratrol and the inhibition of polyomavirus proliferation.10 The researchers suggest that polyphenols may destroy the cells’ membranes or entry into the cell, thus preventing the virus from getting into the cell and reducing its ability to replicate.10,11

Early research on fruit juices supports the findings of the work on polyphenol extracts, indicating a role for grape juice in reducing/inhibiting virus activity.4,5

  • A laboratory study presented by Ferrari and colleagues in 2009 found that rotavirus introduced to monkey kidney cells treated with store-bought cranberry or grape juice beverages showed no virus attachment to or penetration within the cells.4
  • A similar study using Concord and Niagara grape juices and cranberry juice cocktail found that cells treated with these juices helped prevent viruses from infecting by protecting tight junctions, regions between cell membranes. While all the beverages showed a significant protective effect on tight junctions, the effect was greater with Concord and Niagara grape juices.5

Bottom Line

Research in immune function and Concord grape juice has not been well studied in humans or animal models. In vitro studies at this point have focused on Concord grape products and other polyphenolic compounds, like resveratrol. Much additional research is needed in this area to support the initial findings.


  1. Percival SS. Grape consumption supports immunity in animals and humans. J Nutr. 2009. 139(9):1801S-1805S.
  2. Zhang XY, Li WG, Wu YJ, Zheng TZ, Li W, Qu SY and Liu NF. Proanthocyanidin from grape seeds potentiates anti-tumor activity of doxorubicin via immunomodulatory mechanism. Int Immunopharmacol. 2005. 5(7-8):1247-1257.
  3. 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. Mol Nutr Food Res. 2007. 51(6):752-758.
  4. 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.
  5. 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.
  6. 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. 2010. 177-195.
  7. Rowe CA, Nantz MP, Nieves CJ, West RL and Percival SS. Regular Consumption of Concord Grape Juice Benefits Human Immunity. J Med Food. 2011. 14(1-2):69-78.
  8. Vislocky LM and Fernandez MLF. Biomedical Effects of Grape Products. Nutrition Reviews. 2010. 68(11): 656-670.
  9. Falchetti R, Fuggetta MP, Lanzilli G, Tricarico M and Ravagnan G. Effects of resveratrol on human immune cell function. Life Sci. 2001. 70(1):81-96.
  10. Berardi V, Ricci F, Castelli M, Galati G and Risuleo G. Resveratrol exhibits a strong cytotoxic activity in cultured cells and has an antiviral action against polyomavirus: potential clinical use. J Exp Clin Cancer Res. 2009. 28:96.
  11. Evers DL, Wang X, Huong SM, Huang DY and Huang ES. 3,4',5-Trihydroxy-trans-stilbene (resveratrol) inhibits human cytomegalovirus replication and virus-induced cellular signaling. Antiviral Res. 2004. 63(2):85-95.
Eating a balanced diet rich in a variety of fruits and vegetables is important for maintaining overall health. Delicious Concord grapes and 100% grape juice are part of a nutritious diet, but they should not be used to treat health problems. If you are worried about your health or are faced with a medical concern, be sure to consult with your doctor.

Guide to Navigating Research Studies

The definition of scientific research is performing a methodical study in order to prove a theory or answer a question. The following is a brief overview of different types of research used in health and nutrition exploration 1:

Case-Control Study
Clinical Study
Cohort Study
Cross-Sectional Study
Observational Study
Pilot Study
Preclinical or Laboratory Studies
Randomized Controlled Trials


1. Hulley SB, Cummings SR, Browner WS, Grady D, Hearst N, Newman TB. Designing Clinical Research: An Epidemiologic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.

round corners

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.