Blueberries and strawberries: modest numbers from many small trials

In a meta-analysis of 14 randomized trials in 632 healthy people, eating blueberries raised flow-mediated dilation, a measure of how well arteries widen, by 1.11 percentage points (95% CI 0.50 to 1.72), with dose, form and trial length varying a lot between studies. A separate meta-analysis of 14 strawberry trials found diastolic blood pressure 2.2 mmHg lower, total cholesterol 6.5 mg/dL lower and fasting blood sugar 2.1 mg/dL higher, mostly with freeze-dried strawberry powder, and its abstract gives p values without confidence intervals. The two berries differ most in vitamin C. In USDA samples, raw strawberries averaged about 60 mg per 3.5 oz (100 g) and raw blueberries about 8 mg, and blueberries ranged widely, from 4.3 to 11.1 mg. The brain claims are thinner than the marketing. Pooling 6 blueberry trials showed no significant change in mood score (WMD 0.03, 95% CI -0.80 to 0.87). One working memory test, two-back accuracy, improved slightly.

How much is actually in it

• Raw strawberries average about 60 mg of vitamin C per 3.5 oz (100 g) (range 47 to 72 across 8 samples), roughly seven times the 8 mg of raw blueberries (range 4.3 to 11.1). — USDA Foundation Foods samples, 8 per fruit (n = 8 + 8) Evidence E source
  Strawberries 59.62 mg/100 g (47.25-72.1); blueberries 8.059 mg/100 g (4.295-11.1)
• Per 100 g raw, blueberries carry about 4.9 g fructose and 4.4 g glucose, nearly twice the 2.6 g and 2.2 g in strawberries. — USDA Foundation Foods samples, 8 per fruit (n = 8 + 8) Evidence E source
  Blueberries fructose 4.939 g (3.92-6.9), glucose 4.417 g (3.38-6.39); strawberries fructose 2.618 g (1.91-3.13), glucose 2.244 g (1.6-2.795)

What a real portion looks like

• In the US dietary survey database, one cup of either raw blueberries or raw strawberries is coded as 150 g, while one strawberry is 18 g and one blueberry 2 g. — FNDDS portion weights Evidence E source
  1 cup = 150 g (both); 1 fruit strawberry 18 g; 1 berry blueberry 2 g

What your body absorbs

• In a small randomized trial, a strawberry drink made with milk instead of water cut the relative bioavailability of strawberry anthocyanins by about 50% when taken without a meal, with no such effect alongside a meal. — 9 healthy participants; subset of 4 for the no-meal condition (n = 9) Evidence B source
  Relative oral bioavailability of pelargonidin anthocyanins about -50% with milk, fasting only
• In a crossover trial in 9 adults eating 8.8 oz (250 g) of blueberries, whole fruit left 108 urinary ions higher than juiced fruit 2 hours later, against 8 higher after juice. — 9 healthy subjects, single 250 g dose, samples at 2 h (n = 9) Evidence B source
  108 vs 8 urinary ions significantly higher (whole vs juiced)
• In a 4-way crossover RCT in 18 adults, a 5.3 oz (150 g) serving of raw blueberries and a protein bar with the same blueberries gave similar serum polyphenol exposure over 48 hours, though timing of the peak differed. — 18 adults, 42 +/- 12.5 years, 5.3 oz (150 g) serving, 48 h sampling (n = 18) Evidence B source
  Serum AUC similar; Tmax 3.84 h (raw) vs 2.60 h (bar) for one metabolite

What cooking and storage change

• By the USDA retention table for Fruits and Fruit Juices, frozen fruit keeps about 70% of its vitamin C and 90% of its potassium, with iron and magnesium unchanged. — food group Fruits and Fruit Juices, method FRUITS,FROZEN Evidence E source
  Vitamin C 70% retained; potassium 90%; folate 95%; iron, magnesium 100%

What it does to your health

• In a meta-analysis of 14 RCTs (632 healthy people), eating blueberries raised flow-mediated dilation by 1.11 percentage points, with no measurable change in blood pressure. — healthy individuals, 14 RCTs, 632 participants (n = 632) Evidence A source
  FMD +1.11% (95% CI 0.50 to 1.72); SBP -0.11 mmHg (95% CI -2.82 to 2.60), not significant
• A meta-analysis of 14 trials found strawberry supplementation lowered diastolic blood pressure by about 2.2 mmHg and total cholesterol by about 6.5 mg/dL, while fasting blood sugar rose by about 2.1 mg/dL. — 20 groups from 14 clinical trials (n = 14 trials) Evidence A source
  DBP MD -2.220 mmHg; total cholesterol MD -6.49 mg/dL; fasting glucose MD +2.083 mg/dL

Safety, limits and interactions

• In an RCT of 61 breastfed infants given up to 10 g a day of freeze-dried blueberry powder from 5 to 12 months, allergy-related symptoms resolved more often than with placebo. — breastfed US infants, 5 to 12 months of age, 61 completers (n = 61) Evidence B source
  Symptom trajectories differed (p = 0.05); serum IL-13 reduced (p = 0.035)
• In healthy volunteers, blueberry juice did not significantly change blood levels of buspirone or flurbiprofen, unlike grapefruit juice, which doubled buspirone exposure. — healthy volunteers Evidence C source
  Buspirone AUC ratio 1.39 (not significant) vs 2.12 for grapefruit juice; flurbiprofen AUC ratio 1.03

What people believe that the data does not support

• The EU did not authorize a claim that blueberries have anti-aging properties and maintain urinary tract and vision health. — EU claims register, claim POL-HC-7636 Evidence E source
  Non-authorized

Who this works differently for

• In a crossover RCT in 35 healthy older adults, 26 g a day of freeze-dried strawberry powder (about 2 cups fresh) for 8 weeks lowered systolic blood pressure and improved processing speed. — 35 healthy older adults, age 72 +/- 6 years, 8 weeks per phase (n = 35) Evidence B source
  SBP reduced (p = 0.044); processing speed improved (p < 0.001); size not given in abstract

What is still unknown

• Evidence that blueberries improve gut health comes from 16 animal studies in mice and rats, and the reviewers flag significant knowledge gaps for humans. — 16 preclinical studies, 11 in mice and 5 in rats (n = 16 studies) Evidence D source
  Narrative synthesis, no pooled estimate
• A meta-analysis of blueberry trials found no significant change in mood score, with a small gain in two-back test accuracy. — 14 randomized trials reviewed, 6 pooled (n = 6 pooled trials) Evidence A source
  Mood WMD 0.03 (95% CI -0.80 to 0.87); two-back accuracy WMD 0.08 (95% CI 0.02 to 0.13)

The bottom line

A cup of either berry is 150 g in the US dietary survey. A single strawberry is counted at 18 g and a single blueberry at 2 g. Per 100 g, blueberries carry about 4.9 g of fructose and 4.4 g of glucose, close to twice the 2.6 g and 2.2 g in strawberries. By the USDA retention table, frozen fruit keeps about 70 percent of its vitamin C and 90 percent of its potassium, a factor for the whole fruit group set in 1975, untested on these berries specifically. How you eat them matters a little, in small studies. When 9 adults ate 8.8 oz (250 g) of blueberries, the whole fruit left 108 compounds higher in urine two hours later than the juiced fruit, and juice left only 8 higher, measured at a single time point. In 18 adults, 5.3 oz (150 g) of raw blueberries and a protein bar made with the same berries gave similar blood polyphenol exposure over 48 hours. Mixing a strawberry drink with milk instead of water cut anthocyanin uptake by about half on an empty stomach, a result from only 4 people, and made no difference with a meal. In 35 healthy adults around 72 years old, 26 g a day of freeze-dried strawberry powder for 8 weeks lowered systolic blood pressure (p = 0.044) and sped up processing. Episodic memory improved during the control phase instead, and the abstract gives no sizes. Claims that blueberries help the gut rest on 16 studies in mice and rats, and the reviewers say the human evidence has significant gaps. A blueberry juice drink was refused an EU claim that blueberries have anti-aging properties and maintain urinary tract and vision health. That refusal means the evidence was not enough at the time, which is different from proof of no effect. For medicines, blueberry juice did not significantly change blood levels of buspirone or flurbiprofen in healthy volunteers (exposure ratios 1.39 and 1.03), while grapefruit juice doubled buspirone exposure. That study tested juice in a small non-randomized design, and strawberries were not studied. On children, 61 breastfed infants given up to 10 g a day of freeze-dried blueberry powder from 5 to 12 months saw allergy-related symptoms resolve more often than on placebo (p = 0.05), though the blueberry group started with more symptoms. It is one small trial of a powder, not a guide to feeding infants. We have no card on berry allergy or pregnancy, so this page cannot say who should avoid either berry.

Sources

1. bbsb3-07 · food composition data
   Blueberries, raw (Foundation Foods): Vitamin C, total ascorbic acid 8.059 mg per 100 g, range 4.295-11.1, 8 samples; Strawberries, raw (Foundation Foods): Vitamin C, total ascorbic acid 59.62 mg per 100 g, range 47.25-72.1, 8 samples
   USDA FoodData Central, Foundation Foods, release 2026-04-30 (Blueberries, raw; Strawberries, raw; Vitamin C, total ascorbic acid) · checked 2026-10-02
2. bbsb3-08 · food composition data
   Blueberries, raw (Foundation Foods): Fructose 4.939 g, range 3.92-6.9; Glucose 4.417 g, range 3.38-6.39, 8 samples; Strawberries, raw (Foundation Foods): Fructose 2.618 g, range 1.91-3.13; Glucose 2.244 g, range 1.6-2.795, 8 samples
   USDA FoodData Central, Foundation Foods, release 2026-04-30 (Blueberries, raw; Strawberries, raw; Fructose, Glucose) · checked 2026-10-02
3. bbsb3-09 · dataset
   FNDDS 63203010 Blueberries, raw: 1 berry = 2 g; 1 cup = 150 g. FNDDS 63223020 Strawberries, raw: 1 fruit = 18 g; 1 cup = 150 g
   USDA FNDDS (fdc_id 2709275 Blueberries, raw; 2709283 Strawberries, raw) · checked 2026-10-02
4. bbsb3-04 · RCT, pharmacokinetics
   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 2026-10-02
5. bbsb3-05 · RCT, metabolomics
   Nine healthy subjects consumed 250 g of fresh blueberries either as the whole fruit or after juicing ... In urinary samples, whole blueberry treatment resulted in 108 ions that were significantly higher compared with juiced treatment (positive and negative mode combined), whereas only eight were significantly higher after juiced treatment.
   Br J Nutr, 2018 · checked 2026-10-02
6. bbsb3-06 · RCT, pharmacokinetics
   Serum AUC was similar across berry-derived treatments, whereas differences in maximum concentration (Cmax) and time at maximum concentration (Tmax) were observed
   Am J Clin Nutr, 2025 · checked 2026-10-02
7. bbsb3-10 · dataset
   USDA-RETN-R6:156 FRUITS,FROZEN, Fruits and Fruit Juices: vitamin_c_mg 70%; potassium_mg 90%; folate_total_ug 95%; iron_mg 100%; magnesium_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 156 · checked 2026-10-02
8. bbsb3-01 · meta-analysis of RCTs
   we analyzed 14 randomized controlled trials (RCTs) involving 632 participants. Results indicated that blueberry intervention significantly improved flow-mediated dilation (FMD) by 1.11% (95% CI: 0.50, 1.72
   Nutr Res, 2026 · checked 2026-10-02
9. bbsb3-02 · meta-analysis of RCTs
   A total of 20 groups from 14 clinical trials were included for final analysis. ... total cholesterol (MD = -6.49 mg dL-1, p = 0.019), and diastolic blood pressure (MD = -2.220 mmHg, p = 0.033). It also demonstrated raised fasting blood sugar (MD = 2.083 mg dl-1; p = 0.040)
   Food Funct, 2019 · checked 2026-10-02
10. bbsb3-12 · RCT
    infants from the Denver metro area were assigned to receive up to 10 g/day of freeze-dried blueberry powder or an isocaloric placebo from 5 to 12 months of age. ... While more infants in the blueberry group had allergy-related symptoms at baseline, they had significantly different longitudinal symptom trajectories than the placebo (p = 0.05), showing a greater resolution rate of symptoms by study end.
    Nutrients, 2025 · checked 2026-10-02
11. bbsb3-13 · controlled clinical trial
    The geometric mean ratio (GMR = AUC with GFJ divided by AUC with water) was 2.12. In contrast, the effect of BBJ (GMR = 1.39) was not significant. In the study of flurbiprofen (CYP2C9 substrate), the positive control inhibitor fluconazole significantly increased flurbiprofen AUC (GMR = 1.71), but BBJ had no significant effect (GMR = 1.03).
    Br J Clin Pharmacol, 2013 · checked 2026-10-02
12. bbsb3-11 · regulatory decision
    POL-HC-7636 Name of Food product: Sqeez Wild Blueberry Juice Drink Description of food in terms of food legislation categories: food not covered by specific food legislation Was food on Irish market before 1st July 2007: Yes Exact wording of claim as it appears on product: Blueberries have a wide range of health benefits including anti-ageing properties and the maintenance of urinary tract and vision health Is claim a picture: No Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7636, snapshot 2026-09-21 · checked 2026-10-02
13. bbsb3-03 · RCT
    35 healthy older adults (17 women, 18 men, age 72 ± 6 years, BMI 26.4 ± 3.9 kg/m2) consumed 26 g of freeze-dried strawberry powder (strawberry) and a control powder (control) daily for 8 weeks each with a 4-week washout period. ... 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 2026-10-02
14. bbsb3-14 · systematic review, animal
    Sixteen studies included from four countries are reviewed and the results are synthesized narratively. ... However, there are significant knowledge gaps in this field.
    Mol Nutr Food Res, 2023 · checked 2026-10-02
15. bbsb3-15 · meta-analysis of RCTs
    Blueberry intervention resulted in no significant change in mood state score (WMD = 0.03; 95% CI: -0.80 to 0.87, P = 0.16). ... Significant effect was indicated (WMD = 0.08; 95% CI: 0.02 to 0.13, P = 0.005) in two-back test accuracy.
    CNS Neurol Disord Drug Targets, 2023 · checked 2026-10-02