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Blueberries, strawberries and other berries: what the evidence says

Blueberries, strawberries, raspberries and their kin are rich in the pigments called anthocyanins. The trials are small and short, and the clearest result is for blood vessel function.

By the editors of Alimentotherapy Last reviewed October 19, 2026 4 min read Not medical advice

Berries

Best-supported use: Blood vessel function (blueberries)

EvidenceModeratebest use

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The short answer

Berries have moderate evidence for one thing: across 14 randomized trials, blueberries improved flow-mediated dilation, a measure of how well arteries widen, by about 1 percentage point He 2026. Effects on blood pressure, cholesterol, memory and blood sugar come from small, short trials with mixed results, so they are graded limited Huang 2016; Dasilva 2025.

The evidence, use by use

Each claim graded on human studies only. How we grade

Use	Grade	What the research found
Blood vessel function (flow-mediated dilation)	Moderate	A 2026 meta-analysis of 14 randomized trials (632 healthy people) found blueberries improved flow-mediated dilation by 1.11 percentage points. In a 6-month trial in 115 adults with metabolic syndrome, 1 cup of blueberries a day improved vascular function; half a cup did not. He 2026; Curtis 2019
Blood pressure and LDL cholesterol	Limited	A meta-analysis of 22 trials of various berries (1,251 people) found small falls in LDL and systolic blood pressure (about 2.7 mm Hg). A later blueberry meta-analysis found no blood pressure effect in healthy people. Huang 2016; He 2026; Johnson 2015
Memory in older adults with mild cognitive decline	Limited	Nine trials (513 older adults with mild cognitive impairment or subjective decline) found a small improvement in episodic memory with blueberries, but no change in processing speed or working memory. In healthy people, 14 trials found no clear effect on thinking or mood. Dasilva 2025; He 2026
Blood sugar	Limited	The 22-trial berry meta-analysis found a small fall in fasting glucose and HbA1c. A 25-person crossover trial in prediabetes found 32 g of freeze-dried strawberries a day for 12 weeks improved insulin resistance and HbA1c. Huang 2016; Basu 2025

What the trials actually tested

Most berry trials give people freeze-dried berry powder so it can be matched against a look-alike placebo powder. The amounts are meant to be realistic: the longest blueberry trial compared powder equal to half a cup and a full cup of fresh blueberries a day Curtis 2019, and a strawberry trial used 32 g of freeze-dried strawberries, described as about 2.5 servings of fresh fruit Basu 2025. That makes the results easier to apply to a breakfast bowl than many herbal trials, but the trials are small, and many last only weeks.

Blood vessels and blood pressure

The most consistent finding is for flow-mediated dilation, an ultrasound test of how well an artery widens when blood flow increases. A 2026 meta-analysis of 14 blueberry trials with 632 healthy participants found an average improvement of 1.11 percentage points, with low variation between trials. The same analysis found no change in systolic or diastolic blood pressure He 2026.

The best single trial ran for six months in 115 adults with metabolic syndrome, average age 63. One cup of blueberries a day improved arterial stiffness and, in people not taking statins, raised HDL cholesterol. Half a cup a day changed nothing, and insulin resistance, the main outcome, did not improveCurtis 2019.

Some smaller trials did find lower blood pressure. In 48 postmenopausal women with raised blood pressure, 22 g of freeze-dried blueberry powder a day for eight weeks lowered systolic pressure from 138 to 131 mm Hg, with no change on placebo Johnson 2015. A 2016 meta-analysis of 22 trials across different berries found an average fall of about 2.7 mm Hg in systolic pressure and a small drop in LDLHuang 2016. Put together, a small blood pressure effect is possible, mostly in people whose pressure is already raised, and not reliable enough to count on.

Memory and thinking

Blueberries are often sold as brain food. The trials are less sure. In healthy people, the 14-trial meta-analysis found no significant effect on executive function or mood He 2026. In older adults with mild cognitive impairment or subjective memory complaints, nine trials with 513 people found a small improvement in episodic memory, with no change in processing speed, recognition or working memoryDasilva 2025. In a crossover trial in 35 healthy older adults, freeze-dried strawberry powder equal to 2 cups of fresh strawberries a day improved processing speed and lowered systolic blood pressure over eight weeks Delaney 2025.

None of this shows that berries change the course of dementia. Anyone worried about memory should see a clinician; berries are a fine part of the diet either way.

Fresh, frozen or dried

Frozen berries keep for months and are often cheaper than fresh out of season. Dried berries and juices often carry added sugar, so check the label. Freeze-dried powders are closest to what the trials used.

In the kitchen

FDA advises keeping perishable fruit such as strawberries in a refrigerator at 40°F or below, and rinsing produce under running water just before eating it, without soap or produce washFDA. Rinse berries just before you eat them, not before storing, so they do not go soft.

Fresh or frozen berries from the supermarket are the obvious choice. If you want the freeze-dried form used in many trials, iHerb lists freeze-dried blueberries; choose ones with no added sugar.

Before you try it: safety and interactions

Who should avoid it or ask first

You are allergic to a particular berry: avoid that fruit.
You are relying on berries for blood pressure, blood sugar or memory problems: the trial effects are small, so keep your clinician involved and take any prescribed medicines as directed.

Possible side effects

Berries are a normal food and side effects at food amounts are uncommon. Large amounts of fruit can loosen stools in some people.
Dried berries, juices and sweetened powders can carry a lot of added sugar.

Pregnancy and breastfeeding

Berries are a normal food in pregnancy and breastfeeding. Wash fresh berries under running water before eating, as with all produce. FDA; Huang 2016

Medicine interactions

We found no well-documented medicine interactions for berries at food amounts. That is not proof there are none: tell your pharmacist about any herb or supplement you take.

Check another food or medicine in the interactions list.

Common questions

Do blueberries lower blood pressure?

Not reliably. One trial in 48 postmenopausal women with raised blood pressure found 22 g of freeze-dried blueberry powder a day lowered it over eight weeks, but a 2026 meta-analysis of 14 trials in healthy people found no blood pressure change. The clearer effect is a small improvement in how well arteries widen.

Are blueberries good for memory?

The evidence is limited. A 2025 meta-analysis of nine trials in older adults with mild memory problems found a small improvement in episodic memory, but trials in healthy people found no clear effect on thinking or mood.

Are frozen berries as good as fresh?

Trials have not compared them directly, and most used freeze-dried powder rather than fresh fruit. Frozen berries without added sugar are a practical, cheaper way to eat berries year-round.

Sources

Primary research and government sources, each checked on the date this page was reviewed.