Grapes and strawberries: close in the fruit bowl, far apart on the label

The strongest study touching these two fruits is a meta-analysis of 45 randomized trials, in which berries as a group lowered systolic blood pressure by 3.68 mmHg, with a 95% confidence interval of 0.58 to 6.79 mmHg. Grape and freeze-dried strawberry were in that pool, but neither showed a significant effect of its own, so the number cannot be credited to them. The clear difference between the two is on the label. Raw strawberries carry 59.62 mg of vitamin C per 3.5 oz (100 g) against 3.0 to 3.3 mg in red and green grapes, across 8 USDA samples per food, and even the richest grape sample stayed far below the poorest strawberry. The UK table gives grapes 65 calories and 16.1 g of sugar per 3.5 oz (100 g) against 30 calories and 6.1 g in strawberries, with a third of the fiber. A cup of either weighs 5.3 oz (150 g) in the US dietary survey, while one grape weighs 7 g and one strawberry 18 g.

How much is actually in it

• Raw strawberries carry about 18 to 20 times more vitamin C than raw grapes, 59.62 mg against 3.0 to 3.3 mg per 3.5 oz (100 g) in USDA Foundation samples. — USDA Foundation Foods samples of Strawberries, raw and Grapes, red and green, seedless, raw (n = 8 samples per food) Evidence E source
  Strawberries vitamin C 59.62 mg per 3.5 oz (100 g) (range 47.25 to 72.1); red grapes 3.308 mg (range 2.18 to 4.905); green grapes 3.017 mg (range 1.55 to 4.41); potassium 160.7 mg in strawberries against 229.4 and 218.1 mg in red and green grapes
• In the UK food table grapes have about twice the energy and sugar of strawberries and about a third of the fiber. — CoFID 2021 records 14-350 Grapes, average and 14-324 Strawberries, raw (n = 2 records) Evidence E source
  Grapes 65 calories, total sugars 16.1 g, AOAC fiber 1.3 g, vitamin C 2 mg per 3.5 oz (100 g); strawberries 30 calories, total sugars 6.1 g, AOAC fiber 3.8 g, vitamin C 57 mg per 3.5 oz (100 g)

What a real portion looks like

• The US dietary survey counts a cup of either fruit as 150 g, but one grape weighs 7 g and one strawberry 18 g. — FNDDS portion weights for Grapes, raw (63123000) and Strawberries, raw (63223020) (n = 2 foods) Evidence E source
  1 cup 150 g for both; 1 grape 7 g; 1 strawberry 18 g; quantity not specified 75 g for both

What your body absorbs

• In a small crossover trial, making a strawberry drink with milk instead of water cut the relative bioavailability of strawberry anthocyanins by about 50% when taken without a meal. — 9 healthy participants, subset of 4 for the no-meal condition (n = 9) Evidence B source
  Milk lowered peak plasma pelargonidin-3-glucoside, pelargonidin-glucuronide and pelargonidin-3-rutinoside; relative bioavailability about 50% lower without a meal (p < 0.05), no change with a meal
• About a quarter of the flavan-3-ols from grapes reach the body in measurable form, a figure resting on only two grape studies. — 49 human intervention studies of flavan-3-ol intake, 2 of them with grape (n = 49 studies) Evidence C source
  Mean flavan-3-ol bioavailability 31% (SD 23); about 25% after tea, cocoa, apples and grape (grape n = 2); 82% for pure epicatechin

What cooking and storage change

• Freezing or stewing fruit keeps about 70% of its vitamin C in the USDA retention table, which matters for strawberries far more than for grapes. — USDA retention factors for the group Fruits and Fruit Juices, the group of both fruits Evidence E source
  Vitamin C 70% retained frozen (Retn_Code 156) and stewed (Retn_Code 155); folate 95% frozen and 50% stewed; potassium 90% in both

What it does to your health

• A single dose of 46 g grape powder, equal to 8.9 oz (252 g) of fresh grapes, did not change blood glucose or triglycerides after two meals in 25 adults with obesity. — 25 adults with obesity (BMI 30 to under 40), crossover, single dose (n = 25) Evidence B source
  No significant difference from placebo in postprandial glucose, insulin, triglycerides or plasma antioxidant capacity over 6 hours
• Observational data link eating raisins or grapes with a lower risk of hypertension, within a meta-analysis where total fruit gave RR 0.93 per 200 g a day. — 18 prospective studies, 451,291 participants, 145,492 cases (n = 451291) Evidence C source
  Fruit RR 0.93 (95% CI 0.89 to 0.98) per 200 g/day; inverse association reported for raisins or grapes (2 to 5 studies per subtype), no size given in the abstract

Safety, limits and interactions

• In 14 healthy volunteers, 8 oz of grape juice before a dose of flurbiprofen did not change its clearance, although grape juice blocked the same enzyme (CYP2C9) in the test tube. — 14 healthy volunteers, 5-period crossover (n = 14) Evidence B source
  Flurbiprofen clearance 29 to 33 mL/min and half-life 3.3 to 3.4 h unchanged by grape juice; fluconazole control cut clearance to 17 mL/min
• One case report describes a 73-year-old woman on warfarin whose INR rose above target after two months of eating scuppernong muscadine grapes. — 1 woman aged 73 on warfarin (n = 1) Evidence D source
  INR elevated to supratherapeutic levels, judged a probable interaction
• In people with lipid transfer protein allergy, grapes can trigger anaphylaxis, and a painkiller such as ketoprofen taken at the same time can act as a cofactor. — 1 woman aged 26 with lipid transfer protein allergy (n = 1) Evidence D source
  Swelling of lips, tongue and throat, shortness of breath and loss of consciousness after grapes plus ketoprofen

What people believe that the data does not support

• A meta-analysis of 45 randomized trials found berries as a group, including grape and freeze-dried strawberry, lowered systolic pressure by 3.68 mmHg, but in subgroups the effect held only for cranberry and cherry juice. — 45 chronic randomized controlled trials of at least 1 week (n = 45 trials) Evidence A source
  Berries: systolic -3.68 mmHg (95% CI -6.79 to -0.58), diastolic -1.52 mmHg (-2.87 to -0.18); subgroup effects significant only for cranberry and cherry juice
• Europe refused the claim that red grape skin extract helps protect cells from free radical damage, and the EU register holds no authorized claim for strawberries either. — — Evidence E source
  POL-HC-7081 status Non-authorized; 3 grape entries, all Non-authorized; 0 entries for strawberries; no US 21 CFR 101 health claim for either fruit

Who this works differently for

• In a 28-week crossover trial in 25 adults with prediabetes, 1.1 oz (32 g) of freeze-dried strawberries a day for 12 weeks lowered fasting insulin by 6.9 uIU/mL and HbA1c by 0.2 percentage points against no strawberries. — adults with prediabetes, 25 per period, 12 weeks per period (n = 25) Evidence B source
  Insulin -6.9 uIU/mL (95% CI -3.2 to -10.7); HOMA-IR -2.3 (-1.3 to -3.4); fasting glucose -8.9 mg/dL (-4.7 to -13.2); HbA1c -0.2% (-0.1 to -0.3); total cholesterol -7.0 mg/dL (-2.0 to -12.0)
• In 35 healthy older adults, 0.92 oz (26 g) of freeze-dried strawberry a day for 8 weeks lowered systolic blood pressure and sped processing, while episodic memory improved in the control phase instead. — 35 healthy older adults, age 72 +/- 6 years, 8 weeks per phase, crossover (n = 35) Evidence B source
  Systolic blood pressure reduced (p = 0.044), processing speed improved (p < 0.001); episodic memory improved in the control phase (p = 0.002); size of the pressure change not given in the abstract
• Among 582 people on hemodialysis, eating grapes was linked to less fluid overload, while cherries and carrots were linked to more. — 582 patients from 37 Portuguese hemodialysis centers, followed 24 months (n = 582) Evidence C source
  Grape intake associated with lower hyperhydration, independent of age, sex, diabetes and dialysis duration; effect size not given in the abstract

The bottom line

The trials that did find something used dried powders. In 25 adults with prediabetes, 1.1 oz (32 g) of freeze-dried strawberries a day for 12 weeks, about 2.5 servings of the fresh fruit, lowered fasting insulin by 6.9 uIU/mL and HbA1c by 0.2 percentage points against a period without strawberries. That trial was small and had no placebo powder. In 35 healthy older adults, 0.92 oz (26 g) of freeze-dried strawberry a day for 8 weeks lowered systolic pressure with p = 0.044, the abstract gives no size, and episodic memory improved in the control phase instead. For grapes, a single 46 g dose of grape powder, equal to 8.9 oz (252 g) of fresh fruit, did not change blood glucose, insulin or triglycerides over 6 hours in 25 adults with obesity. Observational data link raisins or grapes with a lower risk of hypertension, from 2 to 5 studies per fruit type and with no size given. Europe refused all three grape claims on its register, among them one about red grape skin extract and free radicals, and holds no claim for strawberries. Freezing or stewing keeps about 70% of vitamin C in the USDA group table for fruit, which matters for strawberries far more than for grapes. In a trial of 9 people, with only 4 in the no-meal arm, a strawberry drink made with milk instead of water cut anthocyanin bioavailability by about 50% when taken without a meal. Taken with a meal, milk made no difference. Who should be careful. One case report describes a 73-year-old woman on warfarin whose INR rose above target after two months of eating scuppernong muscadine grapes, a single case with a quercetin-rich variety. In 14 healthy volunteers, 8 oz of grape juice did not change the clearance of flurbiprofen, a marker drug for the same liver enzyme, and the authors called an interaction with warfarin highly unlikely. Read the case as a signal for caution, not a proven interaction. People with lipid transfer protein allergy can react to grapes, and one case of anaphylaxis in a 26-year-old woman followed grapes taken together with ketoprofen. Among 582 people on hemodialysis, grape intake was linked to less fluid overload, an observational finding with no size given, from a study that tested many foods at once. For anyone limiting potassium, USDA samples give 229 and 218 mg per 3.5 oz (100 g) in red and green grapes against 161 mg in strawberries.

Sources

1. gvs-r8-01 · USDA FoodData Central Foundation Foods, dataset
   Strawberries, raw: Vitamin C, total ascorbic acid 59.62 mg per 100 g, range 47.25-72.1, 8 samples; Potassium 160.7 mg, range 121.5-195.0. Grapes, red, seedless, raw: Vitamin C 3.308 mg, range 2.18-4.905, 8 samples; Potassium 229.4 mg. Grapes, green, seedless, raw: Vitamin C 3.017 mg, range 1.55-4.41, 8 samples; Potassium 218.1 mg
   USDA FoodData Central, Foundation Foods, release 2026-04-30 · checked 2026-09-29
2. gvs-r8-02 · CoFID 2021, dataset
   CoFID 14-350 Grapes, average: Energy 65 kcal, Total sugars 16.1 g, AOAC fibre 1.3 g, Potassium 215 mg, Vitamin C 2 mg per 100 g; CoFID 14-324 Strawberries, raw: Energy 30 kcal, Total sugars 6.1 g, AOAC fibre 3.8 g, Potassium 170 mg, Vitamin C 57 mg per 100 g
   CoFID 2021, Public Health England, codes 14-350 and 14-324 · checked 2026-09-29
3. gvs-r8-03 · USDA FNDDS, dataset
   Grapes, raw (FNDDS 63123000, fdc_id 2709237): 1 grape 7 g; 1 cup 150 g; Quantity not specified 75 g. Strawberries, raw (FNDDS 63223020, fdc_id 2709283): 1 fruit 18 g; 1 cup 150 g; Quantity not specified 75 g
   USDA FNDDS, fdc_id 2709237 and 2709283 · checked 2026-09-29
4. gvs-r8-05 · randomized crossover trial
   Milk did not influence the oral relative bioavailability of pelargonidin anthocyanins under meal conditions; however, the oral relative bioavailability of pelargonidin anthocyanins was reduced by ∼50% by milk under without meal conditions (p < 0.05).
   Food Funct, 2017 · checked 2026-09-29
5. gvs-r8-06 · systematic review
   Mean bioavailability for flavan-3-ols was moderate (31 ± 23%, n bioavailability values = 20), and it seems to be scarcely affected by the amount of ingested compounds.
   Mol Aspects Med, 2023 · checked 2026-09-29
6. gvs-r8-04 · USDA Table of Nutrient Retention Factors, dataset
   USDA-RETN-R6:156 FRUITS,FROZEN, group Fruits and Fruit Juices: vitamin_c_mg 70% retained, potassium_mg 90%, folate_total_ug 95%; USDA-RETN-R6:155 FRUITS,FRESH(NOT CITRUS),STEWED: vitamin_c_mg 70% retained, folate_total_ug 50%, potassium_mg 90%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Codes 155 and 156 · checked 2026-09-29
7. gvs-r8-09 · randomized crossover trial
   The grape powder supplementation did not cause any significant modification compared to placebo, in these parameters; nor did it significantly modify plasma antioxidant capacity in the 6 h postprandial period.
   Eur J Nutr, 2021 · checked 2026-09-29
8. gvs-r8-11 · meta-analysis of cohorts
   Inverse associations were observed for apples or pears, blueberries, raisins or grapes, avocado, broccoli, carrots and lettuce
   Eur J Nutr, 2023 · checked 2026-09-29
9. gvs-r8-12 · randomized crossover trial
   Although grape juice and tea impaired CYP2C9 activity in vitro, none of the 3 beverages altered CYP2C9-mediated clearance of flurbiprofen in humans, making a pharmacokinetic interaction with warfarin highly unlikely.
   Clin Pharmacol Ther, 2006 · checked 2026-09-29
10. gvs-r8-13 · case report
    ingestion of scuppernongs, a variety of quercetin-containing muscadine grapes, over a period of 2 months was associated with elevations in the International Normalised Ratio to supratherapeutic levels
    BMJ Case Rep, 2014 · checked 2026-09-29
11. gvs-r8-14 · case report
    This case report describes a 26-year-old female who developed anaphylactic symptoms after ingesting grapes and taking ketoprofen.
    Int J Mol Sci, 2025 · checked 2026-09-29
12. gvs-r8-10 · meta-analysis of RCTs
    Berries including juice of barberry, cranberry, grape, pomegranate, powder of blueberry, grape, raspberry and freeze-dried strawberry significantly reduced SBP by 3.68 mmHg (95% CI - 6.79 to - 0.58; P = 0.02) and DBP by 1.52 mmHg (95% CI - 2.87 to - 0.18, P = 0.04).
    Eur J Nutr, 2021 · checked 2026-09-29
13. gvs-r8-15 · regulatory register entry
    POL-HC-7081 Extract from the red grapes skin Helps to protect cells from the free-radical damage Helps to protect cells from the damage caused by free-radical Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7081, snapshot 2026-09-21 · checked 2026-09-29
14. gvs-r8-07 · randomized crossover trial
    Strawberry period significantly improved glycemic control (serum insulin, insulin resistance, fasting glucose and glycated hemoglobin) and serum total cholesterol in an adjusted model compared with control
    J Nutr, 2025 · checked 2026-09-29
15. gvs-r8-08 · randomized crossover trial
    Processing speed (p < 0.001) improved during the strawberry phase and episodic memory (p = 0.002) improved during the control phase. For cardiovascular measures, strawberry consumption reduced systolic blood pressure (p = 0.044)
    Nutr Metab Cardiovasc Dis, 2025 · checked 2026-09-29
16. gvs-r8-16 · cohort
    Consumption of bacon, savory snacks, carrots, bell peppers, cherries, and soup predicted greater hyperhydration, while rice, cookies, and grapes show the opposite effect, regardless of age, sex, diabetes, and HD duration.
    Clin Nutr ESPEN, 2026 · checked 2026-09-29