NutriDex

The Supplement Research Compendium
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Red Grape

Vitis vinifera

Polyphenol-rich berries with modest cardiometabolic signals

Moderate evidence 🍎Fruits

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
10 verified / 10
Classification
Fruits
❝
What the evidence says. Several controlled trials; effects real but modest or context-dependent.

Nutrition per serving 1 cup (151 g)

151gSERVING
  • Water 121.6 g81%
  • Sugars 23.4 g16%
  • Fibre 1.4 g1%
  • Other carbs 2.5 g2%
  • Protein 1.1 g1%
  • Fat 0.2 g0%
What's in one serving, by weight — average composition (USDA).
Vitamin K18.4%Copper21.1%Vitamin C5.4%Potassium6.1%Thiamin (B1)8.8%Vitamin B67.6%Manganese4.6%
One serving as % of the adult daily requirement (FDA Daily Values). The bold outer ring = 100% of a day's needs.
104 kcal1.1 g protein1.4 g fiber0.24 g fat
NutrientPer serving% daily value
Vitamin K22 ug18.4%
Copper0.19 mg21.1%
Vitamin C4.8 mg5.4%
Potassium288 mg6.1%
Thiamin (B1)0.11 mg8.8%
Vitamin B60.13 mg7.6%
Manganese0.11 mg4.6%
Riboflavin (B2)0.11 mg8.1%
Fibre1.4 g5%

Composition data: USDA FoodData Central ↗

What is Red Grape?

Red Grape (Vitis vinifera) is a fruit used for modest reduction in systolic blood pressure (whole-grape rcts). NutriDex grades the human evidence as Moderate. Human evidence for red grapes rests mainly on whole-grape and grape-product RCTs plus large prospective cohorts. Meta-analyses of randomized trials show a small but significant fall in systolic blood pressure (around 3 mmHg) with grape products, with whole forms (powder, raisins) outperforming juice, but no consistent effect on diastolic pressure or endothelial markers. In the Nurses' Health and Health Professionals cohorts, higher intake of grapes/raisins and other anthocyanin-rich fruits tracked with modestly lower type 2 diabetes risk. Small Concord grape-juice trials suggest memory benefits in older adults with cognitive decline, but samples are tiny. Overall the data are consistent for cardiometabolic surrogate endpoints yet limited by short durations, surrogate outcomes, heterogeneous grape products, and generally low certainty of evidence. No RCTs demonstrate that eating grapes reduces hard clinical events.

Purported Benefits

✓Modest reduction in systolic blood pressure (whole-grape RCTs)
✓Improved endothelial/vascular function in some trials
✓Associated with lower type 2 diabetes risk in large cohorts
✓Favourable effects on LDL oxidation and oxidative stress
✓Possible support for memory in older adults (small grape-juice RCTs)
✓Antioxidant and anti-inflammatory polyphenol intake

Dosing & Compounds

Typical Dose
A typical serving is about 1 cup (~150 g, ~17 grapes); intervention trials use roughly 0.5-2 cups equivalent of whole grapes, grape powder, or 250-500 mL juice daily over 4-16 weeks.
Active Compounds
Anthocyanins (peonidin/cyanidin/malvidin-3-glucoside)Flavan-3-ols (catechin, epicatechin, proanthocyanidins)Stilbenes (resveratrol, piceid)Flavonols (quercetin, kaempferol)Phenolic acids (caftaric, gallic acid)Vitamin KCopperPotassiumVitamin C

Safety & Cautions

High in free sugars (~23 g per cup) and easy to overeat, so portion control matters for glycaemic control and weight. A common choking hazard for young children (halve them). Grape allergy and oral allergy syndrome occur but are uncommon. Note this is GRAPE, not grapefruit: ordinary grapes lack the furanocoumarins that cause grapefruit-CYP3A4 drug interactions, though concentrated grape-seed or resveratrol supplements may have mild interactions and antiplatelet effects. Dried grapes (raisins) concentrate sugar; pesticide residue is reduced by washing. Educational only — always check with your doctor or pharmacist before combining Red Grape with any medicine.

Key Studies ★ 10 studies

Meta-analysis Ashoori 2023 ✓ PubMed
Systematic review/meta-analysis of 30 RCTs: whole grape products significantly lowered systolic BP (~-3.2 mmHg; whole forms more than juice) but not diastolic BP, endothelial function or heart rate; certainty low.
Meta-analysis Mohammadi 2025 (Int J Food Sci Nutr) ✓ PubMed
Systematic review/meta-analysis of RCTs found whole grapes or grape products had no significant effect on body weight, waist circumference, body fat, leptin or adiponectin; only a trivial BMI reduction (WMD -0.14 kg) of low certainty, with small effects limited to females and metabolic-syndrome subgroups.
Meta-analysis Asbaghi 2022 (Pharmacol Res) ✓ PubMed
Meta-analysis of 19 controlled trials found grape (Vitis vinifera) seed extract significantly lowered diastolic BP (-2.20 mmHg, 95% CI -3.79 to -0.60) and heart rate (-1.25 bpm) but did not significantly change systolic BP (-3.55 mmHg, 95% CI -7.59 to 0.49) or flow-mediated dilation.
Meta-analysis Anjom-Shoae 2020 (Br J Nutr) ✓ PubMed
Dose-response meta-analysis of 11 RCTs (536 participants) found grape seed extract significantly reduced LDL-cholesterol (-0.17 mmol/L, 95% CI -0.34 to -0.01) and triglycerides (-0.11 mmol/L), with no significant change in total or HDL cholesterol.
Agency / regulator NCCIH (NIH) Grape Seed Extract ✓ Source
US National Center for Complementary and Integrative Health states grape seed extract is generally well tolerated but evidence is insufficient to conclude it benefits any health condition, and that high doses or long-term use have not been adequately studied.
RCT Krikorian 2010 ✓ PubMed
12-week Concord grape juice RCT improved verbal learning in older adults with mild memory decline (very small n=12; recall gains non-significant).
RCT Krikorian 2012 ✓ PubMed
16-week Concord grape juice RCT reduced semantic interference on memory tasks and increased task-related brain activation (fMRI) in older adults with mild memory decline.
Review Rasines-Perea 2017 ✓ Full text
Narrative review of grape polyphenols' effects on human cardiovascular disease and diabetes, summarizing antioxidant, anti-inflammatory and vascular mechanisms.
Cohort Muraki 2013 ✓ PubMed
Higher intake of whole grapes/raisins and other fruits associated with lower type 2 diabetes risk (pooled HR 0.88 per 3 servings/wk) across 3 US cohorts; fruit juice raised risk (HR 1.08).
Cohort Wedick 2012 ✓ PubMed
In ~200,000 US adults across 3 cohorts, higher anthocyanin intake was associated with lower incidence of type 2 diabetes (pooled HR ~0.85, extreme quintiles).
10 sources cited · 10 verified Search all studies on PubMed ↗

Common questions about Red Grape

What is Red Grape used for?

Red Grape is most often taken for Modest reduction in systolic blood pressure (whole-grape RCTs), Improved endothelial/vascular function in some trials, Associated with lower type 2 diabetes risk in large cohorts, Favourable effects on LDL oxidation and oxidative stress. Polyphenol-rich berries with modest cardiometabolic signals

Does Red Grape work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Human evidence for red grapes rests mainly on whole-grape and grape-product RCTs plus large prospective cohorts. Meta-analyses of randomized trials show a small but significant fall in systolic blood pressure (around 3 mmHg) with grape products, with whole forms (powder, raisins) outperforming juice, but no consistent effect on diastolic pressure or endothelial markers. In the Nurses' Health and Health Professionals cohorts, higher intake of grapes/raisins and other anthocyanin-rich fruits tracked with modestly lower type 2 diabetes risk. Small Concord grape-juice trials suggest memory benefits in older adults with cognitive decline, but samples are tiny. Overall the data are consistent for cardiometabolic surrogate endpoints yet limited by short durations, surrogate outcomes, heterogeneous grape products, and generally low certainty of evidence. No RCTs demonstrate that eating grapes reduces hard clinical events.

What is the typical dose of Red Grape?

A typical serving is about 1 cup (~150 g, ~17 grapes); intervention trials use roughly 0.5-2 cups equivalent of whole grapes, grape powder, or 250-500 mL juice daily over 4-16 weeks.

Is Red Grape safe? Any cautions or side effects?

High in free sugars (~23 g per cup) and easy to overeat, so portion control matters for glycaemic control and weight. A common choking hazard for young children (halve them). Grape allergy and oral allergy syndrome occur but are uncommon. Note this is GRAPE, not grapefruit: ordinary grapes lack the furanocoumarins that cause grapefruit-CYP3A4 drug interactions, though concentrated grape-seed or resveratrol supplements may have mild interactions and antiplatelet effects. Dried grapes (raisins) concentrate sugar; pesticide residue is reduced by washing.

How many studies support Red Grape?

NutriDex cites 10 sources for Red Grape, graded "Moderate".

Cite this page
APA

Peh, D. (2026). Red Grape (Vitis vinifera): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/red-grape

BibTeX
@misc{nutridex_red_grape,
  author       = {Peh, Daryl},
  title        = {Red Grape (Vitis vinifera): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/red-grape},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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