How much blueberries per day is too much?

No nutrient here reaches an NIH upper limit, the FDA caffeine figure or a Dietary Guidelines limit within 60 of these servings a day. One cup = 1 cup (5.2 oz, 148 g). USDA FoodData Central, Blueberries, raw. Limits count everything you eat and drink that day, so other foods and supplements use up part of each one.

• Level B In an RCT of 57 cognitively healthy adults aged about 73, 20 g a day of freeze-dried blueberry powder for 24 weeks did not change blood markers of brain damage or cognitive test scores. Clin Nutr ESPEN, 2026
• Level B In a 12-week double-blind RCT of 43 postmenopausal women with raised blood pressure, 22 g a day of freeze-dried blueberries improved endothelial function but not blood pressure. Food Funct, 2023
• Level B In an RCT in 34 pregnant women with obesity, 9.9 oz (280 g) of blueberries plus 12 g of soluble fiber a day for 18 weeks had lower gestational weight gain, 6.8 kg versus 26 lb (12.0 kg) on standard care. The share of the berries versus the fiber is unknown. J Nutr, 2021
• Level C Cohort data from 451,291 adults link each extra 7.1 oz (200 g) of fruit a day with a 7% lower risk of hypertension, with inverse associations for blueberries among individual fruits. Eur J Nutr, 2023

Only studies that give the amount eaten. Levels: A is a meta-analysis of trials, B a randomized trial, C an observational study. How we grade evidence.

• Level E NIH ODS states that in people who cannot excrete potassium normally, because of chronic kidney disease or drugs such as ACE inhibitors or potassium-sparing diuretics, even dietary potassium intakes below the Adequate Intake can cause hyperkalemia. This includes potassium from blueberries and grapes. NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals

If you have kidney disease, take blood thinners or other medicines, or are pregnant, the right amount for you is a question for your clinician.

Nothing in blueberries comes near an upper limit, and a cup is 85 calories, so the amount is about what fits your day. The 280 g dose came from a trial in 34 pregnant women with obesity that also added 12 g of soluble fiber, so the berries' share of its result is unknown (Level B).

Results at these doses are mixed. In 43 postmenopausal women, 22 g a day of freeze-dried blueberries improved blood vessel function but not blood pressure (Level B). In 57 older adults, 20 g a day of freeze-dried powder for 24 weeks did not change cognitive scores (Level B).

Blueberries are low in potassium: a cup has about 127 mg in the USDA record, and gram for gram ripe bananas carry almost four times as much (Level E). If you have chronic kidney disease or take ACE inhibitors or potassium-sparing diuretics, NIH ODS says even modest potassium intakes can raise blood potassium, so the cups still count toward your daily total (Level E).

Evidence behind this note

1. Level B In an RCT in 34 pregnant women with obesity, 9.9 oz (280 g) of blueberries plus 12 g of soluble fiber a day for 18 weeks had lower gestational weight gain, 6.8 kg versus 26 lb (12.0 kg) on standard care. The share of the berries versus the fiber is unknown. J Nutr, 2021
2. Level B The trial dose was 1.1 oz (30 g) of freeze-dried blueberry powder a day, equal to about 6.3 oz (180 g) of fresh blueberries. Nutrients, 2023, 15(10):2396 (Blueberries improve abdominal symptoms, well-being and functioning in patients with functional gastrointestinal disorders)
3. Level B In a 12-week double-blind RCT of 43 postmenopausal women with raised blood pressure, 22 g a day of freeze-dried blueberries improved endothelial function but not blood pressure. Food Funct, 2023
4. Level B In an RCT of 57 cognitively healthy adults aged about 73, 20 g a day of freeze-dried blueberry powder for 24 weeks did not change blood markers of brain damage or cognitive test scores. Clin Nutr ESPEN, 2026
5. Level E USDA measured almost four times more potassium in ripe bananas (326 mg per 3.5 oz (100 g)) than in raw blueberries (86 mg per 3.5 oz (100 g)). USDA FoodData Central, Foundation Foods, release 2026-04-30
6. Level E NIH ODS states that in people who cannot excrete potassium normally, because of chronic kidney disease or drugs such as ACE inhibitors or potassium-sparing diuretics, even dietary potassium intakes below the Adequate Intake can cause hyperkalemia. This includes potassium from blueberries and grapes. NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals

Written from the data and studies on this page, reviewed by the Bioma editorial system. How we verify.

• Blueberries: what the research says