Get Your Personalized Supplement StackSupplement Stack Quiz

Concord Grape Juice Concentrate

Also known as: Concord grape, Concord grape juice concentrate, Grape juice concentrate, Vitis labrusca L.

Overview

Concord grape juice concentrate is a concentrated extract from Concord grapes (*Vitis labrusca*), a variety native to North America. It is primarily used as a dietary supplement for its high polyphenol content, including anthocyanins, flavonols (like quercetin), and stilbenes (like resveratrol). These compounds contribute to its antioxidant properties, which are believed to support cardiovascular health and protect against oxidative DNA damage. The concentrate is derived from natural sources and contains natural sugars. Research on Concord grape juice concentrate is moderately mature, with several studies on grape products in general, but fewer high-quality trials specifically focused on the concentrate. Evidence for its benefits is mixed, with some studies showing antioxidant effects, while others report inconsistent results regarding inflammation and metabolic markers.

Benefits

Concord grape juice concentrate has demonstrated the ability to increase antioxidant capacity in the blood, potentially protecting cells from oxidative DNA damage. Meta-analyses of grape products suggest an increase in antioxidant agents, but no significant effect on inflammatory markers. Some evidence indicates that grape products may increase fasting blood glucose levels, suggesting a potential metabolic concern. Meta-analyses of 100% fruit juice consumption, including grape juice, show mostly neutral effects on body weight and cardiovascular health, with some small effect sizes indicating possible benefits for cardiovascular markers. Most studies include healthy adults or animal models, limiting population-specific benefit data. Antioxidant effects are statistically significant; however, clinical significance regarding inflammation or cholesterol is less clear or absent. Antioxidant effects are observed with subchronic treatment (weeks to months).

How it works

The antioxidant polyphenols in Concord grape juice concentrate scavenge reactive oxygen species, reducing oxidative stress and DNA damage. It primarily acts on peripheral blood and liver cells to protect against oxidative damage, potentially modulating cardiovascular and metabolic pathways. Polyphenols such as quercetin and resveratrol target oxidative stress pathways and may influence inflammatory signaling, though inflammation effects are inconsistent. Polyphenols are absorbed in the gut, metabolized to glucuronide forms (e.g., quercetin glucuronide), and circulate systemically.

Side effects

Concord grape juice concentrate is generally considered safe, with no significant adverse effects reported in animal studies or human trials at typical doses. Common, uncommon, and rare side effects are not documented. Potential interactions with blood sugar-lowering drugs may occur due to effects on glucose metabolism, so caution is advised. There are no clearly established contraindications, but caution is advised in individuals with glucose intolerance or diabetes due to the possible increase in fasting glucose. Limited data exists for children, pregnant women, or those with chronic diseases.

Dosage

Clinical studies on grape products use doses ranging from moderate (e.g., 100-300 mL juice equivalent) to higher amounts; specific Concord grape concentrate dosing requires further research. The minimum effective dose is not well established. The maximum safe dose is not clearly defined, but no toxicity has been reported at typical supplemental doses. Benefits are observed with subchronic daily intake. The concentrate form may provide a higher polyphenol content per volume compared to juice. Polyphenol bioavailability may be influenced by the food matrix and gut microbiota. No specific cofactors are identified as required.

FAQs

Is Concord grape juice concentrate effective for reducing inflammation?

Current evidence shows no significant effect on inflammatory markers despite increased antioxidant capacity.

Can it affect blood sugar?

Yes, grape products including Concord grape juice may increase fasting blood glucose, so caution is warranted in people with glucose regulation issues.

Is it safe for long-term use?

Available data suggest it is safe with no major adverse effects reported in studies lasting weeks to months.

Does it help with cholesterol?

No significant cholesterol-lowering effect was observed in animal studies.

How soon can benefits be expected?

Antioxidant benefits appear after weeks of regular consumption.

Research Sources

https://onlinelibrary.wiley.com/doi/10.1155/2024/5086541 – A systematic review and meta-analysis on grape products found increased antioxidant agents but no significant effect on inflammatory markers. The study included RCTs with adequate controls and sample sizes, but was limited by the heterogeneity of grape products studied.
https://www.mdpi.com/2072-6643/14/17/3539 – A meta-analysis comparing Concord grape puree and other grape products showed increased fasting blood glucose levels, indicating a metabolic effect. The RCTs included had n≥30 and proper controls, but the study was limited by variability in product forms and doses.
https://jamanetwork.com/journals/jamapediatrics/fullarticle/2813987 – An umbrella review of 100% fruit juice (including grape juice) consumption showed mostly neutral effects on body weight and cardiovascular health, with small effect sizes for some outcomes. The systematic review followed Cochrane and PRISMA guidelines, but was limited by observational data confounding and dose variability.
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007114510004368 – An animal study demonstrated that subchronic treatment with grape juice concentrate protected against oxidative DNA damage without affecting cholesterol or causing adverse effects. The study included biochemical analysis of polyphenols and metabolites, but was limited by extrapolation from animal to human.