A large Tufts and Queen’s University Belfast team pooled 18 long-term population studies and 65 randomized trials to ask a narrow but important question: do anthocyanins, the red and blue pigments in berries, grapes and red cabbage, help people who are already healthy, rather than people who are already sick. The answer is a qualified yes for blood vessel function. Habitual high intake tracked with lower rates of heart disease, heart attack, diabetes and high blood pressure in observational cohorts, and controlled trials confirmed a real, measurable improvement in how arteries dilate at intakes as low as 50 mg per day, roughly a cup of blueberries. The effects on blood pressure, cholesterol and blood sugar, however, were essentially absent in healthy people. The headline is modest but genuine: anthocyanins are a plausible, food based lever for vascular aging, not a cure for anything.
For decades, nutrition scientists have noticed that people who eat more berries and other deeply pigmented fruit tend to have healthier hearts. The problem has always been untangling correlation from cause, and separating the genuinely healthy population from the already diseased. This new systematic review, published in the American Journal of Clinical Nutrition, is the most careful attempt yet to isolate that signal in people who are not sick.
The big idea is that anthocyanins may act as a preventive tool rather than a treatment. The team deliberately restricted their analysis to healthy, overweight or obese participants and required trials to deliver at least 50 mg of anthocyanins per day, a dose you can actually reach through diet. That threshold matters, because many earlier reviews were muddied by tiny doses or by mixing in patients with established disease, who tend to show exaggerated benefits.
Two lines of evidence converge. In the observational cohorts, spanning hundreds of thousands of people followed for years, those with the highest habitual anthocyanin intake had a 26 percent lower risk of cardiovascular disease, an 18 percent lower risk of heart attack, an 11 percent lower risk of type 2 diabetes, a 9 percent lower risk of dying from cardiovascular causes and an 8 percent lower risk of developing high blood pressure. Stroke risk did not budge.
The randomized trials, the stronger form of evidence, then supplied a mechanism. Anthocyanins reliably improved flow mediated dilation, a measure of how well the inner lining of arteries relaxes and widens. This improvement showed up both within hours of a single dose and after weeks of regular intake. The authors rate the acute effect as strong evidence and the chronic effect as moderate. Fasting insulin dropped slightly as well.
What did not move is as instructive as what did. In healthy people, anthocyanins produced no meaningful change in blood pressure, cholesterol, blood sugar, HbA1c or inflammatory markers. The most likely explanation is a ceiling effect: healthy bodies already regulate these tightly, so there is little room for a food compound to improve them. The takeaway is measured. Anthocyanins look like a legitimate, low risk contributor to vascular health, and the evidence is now strong enough to inform dietary guidelines, but the magnitude is incremental, not transformative.
Actionable Insights
The single most practical message is this: eating anthocyanin rich foods, meaning berries, grapes, cherries, plums, red cabbage and similar deeply colored produce, at roughly 50 to 200 mg per day appears to genuinely improve how well your arteries function, and this shows up even in healthy people.
To put the effect size in plain terms. Flow mediated dilation, the main benefit, improved by about 1.4 percentage points with regular intake. Typical healthy adults sit around 6 to 7 percent, so this is roughly a 20 percent relative improvement in that measure. Translated to a standardized effect size, this is approximately a Cohen’s d of 0.5 to 0.6, which counts as a medium effect. That is real and clinically interesting. The authors note that a 1.4 point rise in this measure has been linked in other research to roughly a 13 to 17 percent lower rate of future cardiovascular events, though that is an extrapolation, not a proven outcome in this study.
By contrast, the fasting insulin drop was tiny, an estimated Cohen’s d near 0.1, which is practically negligible for a healthy person. Blood pressure, cholesterol and blood sugar did not improve at all in healthy people.
Bottom line: a daily cup of blueberries or equivalent is a low cost, low risk habit with a modest but measurable payoff for vascular aging. It is not a substitute for exercise, not smoking, or managing blood pressure and lipids directly.
Context and Source
- Open Access Paper: Dietary intakes of anthocyanins and cardiometabolic health: a systematic review and meta-analysis of randomized trials and prospective cohort studies in healthy participants.
- Authors and institutions: Lead author Esther E. Avendano and colleagues at the Tufts Center for Clinical Evidence Synthesis and Tufts Medical Center, Boston, USA, with collaborators at the University of East Anglia, Norwich, United Kingdom, and senior author Aedin Cassidy at Queen’s University Belfast, United Kingdom.
- Country: United States and United Kingdom collaboration.
- Journal: The American Journal of Clinical Nutrition (Elsevier, on behalf of the American Society for Nutrition), volume 124, 2026.
- Impact evaluation: The impact score of this journal is 6.9 (2024 Journal Impact Factor, released 2025), evaluated against a typical high-end range of 0 to 60+ for top general science, therefore this is a Medium impact journal.