You probably know that eating more fruit is supposed to be good for the heart. Most of us hear it so often that it starts to sound like background noise. A new US trial tried to pin down what actually happens when you commit to it with two specific fruits.
Adults with prediabetes who ate one Hass avocado and one cup of fresh mango every day for eight weeks showed better blood vessel function than a comparison group.
The findings come from a controlled trial by researchers at the Illinois Institute of Technology, published in February 2026 in the Journal of the American Heart Association.
The trial involved 82 adults aged 25 to 60 who were overweight and had prediabetes. That means their blood sugar was high enough to signal elevated diabetes risk, but not high enough for a diabetes diagnosis.
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What the two groups ate every day
Half of the participants added the avocado and the mango to their meals and snacks. The other half ate the same number of calories from starchy alternatives instead.
Everyone followed a meal pattern typical of American diets, with most of the food provided by the researchers. Nobody was asked to cut calories or lose weight.
The one measure that actually moved
The main thing the researchers tracked was a test called flow-mediated dilation. Technicians measure how well an artery in the arm widens when blood flow surges through it. A stiffer, less responsive artery is an early warning sign for heart disease.
In the fruit group that number rose over the eight weeks. In the control group it drifted the wrong way. The difference between the two groups was statistically significant, meaning it was unlikely to be down to chance.
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Men in the fruit group also saw a modest drop in diastolic blood pressure, the lower number on a blood pressure reading. Women did not show the same effect.
What the trial did not change
Cholesterol levels, fasting blood sugar and standard inflammation markers did not improve in the fruit group compared with the controls. Despite adding whole fruit on top of a typical American diet, participants also did not lose weight.
So this is not a cholesterol story. The headline finding from the Illinois team is about vascular function, not a broad reset of cardiometabolic numbers.
Who paid for the research
The study was funded by the National Mango Board and the Hass Avocado Board, two US industry groups. According to Healio, principal investigator Britt Burton-Freeman also received an honorarium and travel reimbursement from the National Mango Board.
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Industry-funded nutrition research is common and not automatically unreliable. Independent experts still flagged important limits.
Cardiologist Brett A. Sealove, chair of cardiology at Hackensack Meridian Jersey Shore University Medical Center, told Healthline that the trial was small and short. Only 68 of the 82 enrolled participants finished the protocol over eight weeks.
A more realistic daily portion
Registered dietitian Karen E. Todd told Healthline that for most people a more moderate pattern is half an avocado and half to one cup of mango several times a week. It works folded into salads, yogurt bowls or smoothies.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.