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Concord Grapes in the News

New Research Supports Concord Grape Juice and Healthy Circulation

Laboratory Study Finds Concord Grape Juice Outperforms Other Fruit Juices in Support of Blood Vessel Health

October 1, 2014

In addition to a healthy lifestyle, a diet rich in fruits and vegetables can help support a healthy heart. Fruits in particular contain a variety of health-promoting plant nutrients (or polyphenols) that can play a role in cardiovascular health, yet not all fruits contain the same types of polyphenols and not all polyphenols have the same effect on the body.

A new study, directed by Dr. Valérie Schini-Kerth at the Université de Strasbourg, shows that the type of polyphenol, not just the amount, is central to the effect on promoting blood vessel relaxation,1 which is associated with healthy circulation and cardiovascular wellbeing. Building off her previous work in this area,2 Schini-Kerth and colleagues sampled a variety of commercially-available fruit juices to determine their ability to induce endothelium-dependent relaxation in a laboratory model.1

Of the 51 fruit juice products examined, three products: a blackcurrant juice, a red juice blend, and specifically Welch’s Concord grape juice had the most potent positive effect on blood vessel health. While these three products also had the highest polyphenol content of the juices, the data suggest that it’s not only the polyphenol concentration that correlates to the relaxation effect, but also the types of polyphenols present. Additionally, the sugar concentration did not correlate with the blood vessel relaxation, which may suggest that sugars do not alter the beneficial effects of polyphenols in fruit juice.

This study builds on the author’s earlier work showing that Concord grape juice has positive effects on blood vessel health3,4 and the nearly twenty years of research suggesting that this juice can support a healthy heart. In fact, the authors note that in the case of Concord grape juice, research has shown an improved endothelial function5,6 and a benefit on both systolic and diastolic blood pressure,7 in certain at-risk people who drink Concord grape juice.

Expert Outlook:
According to the authors: “The present findings are in good agreement with our previous work and indicate that the fruit-derived juices with the largest benefit on vascular activity are predominantly those from berries, including the Concord grape.”

1Auger C, Pollet B, Arnold C, Marx C and Schini-Kerth VB. Great Heterogeneity of Commercial Fruit Juices to Induce Endothelium-Dependent Relaxations in Isolated Porcine Coronary Arteries: Role of the Phenolic Content and Composition. J Med Food. 2014. Epub ahead of print.

2Auger C, Kim JH, Trinh S, Chataigneau T, Popken AM, Schini-Kerth VB. Fruit juice-induced endothelium-dependent relaxations in isolated porcine coronary arteries: evaluation of different fruit juices and purees and optimization of a red fruit juice blend. Food Funct. 2011. 2(5):245–250.

3Alhosin M, Anselm E, Rashid S, Kim JH, Madeira SV, Bronner C and Schini-Kerth VB. Redox-Sensitive Up-Regulation of eNOS by Purple Grape Juice in Endothelial Cells: Role of PI3-Kinase/Akt, p38 MAPK, JNK, FoxO1 and FoxO3a. PLoS ONE. 2013. 8(3):e57883.

4Anselm 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.

5Chou 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.

6Stein 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.

7Park YK, Kim J-S and Kang M-H. Concord grape juice supplementation reduces blood pressure in Korean hypertensive men: double-blind, placebo controlled intervention trial. Biofactors. 2004. 22(1-4):145-147.

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.