Eating an avocado and a cup of mango daily improved blood vessel function in adults with prediabetes

Adults with prediabetes who ate one medium Hass avocado and one cup of fresh mango every day for eight weeks ended the trial with better blood vessel function than a comparison group. In the study from Illinois Institute of Technology, flow-mediated dilation, a standard ultrasound measure of how well arteries widen, rose to 6.7% in the avocado-mango group and fell to 4.6% in controls. The work appears in the Journal of the American Heart Association and was funded by the two fruit industries.

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Britt Burton-Freeman, the Illinois Tech professor who was the principal investigator, said the research reinforces the power of food-first strategies to help reduce cardiovascular disease risk.

Flow-mediated dilation as the measuring stick

The primary outcome was endothelial function, meaning how well the cells lining the arteries respond when blood flow increases. Flow-mediated dilation measures the percentage a brachial artery widens after a short period of restricted flow, and lower values are associated with greater cardiovascular risk. The published paper, “Effects of Increasing Total Fruit Intake With Avocado and Mango on Endothelial Function and Cardiometabolic Risk Factors in Adults With Prediabetes”, appears in volume 15, issue 4 of the journal.

ScienceDaily’s summary of the university release reports the avocado-mango group improved significantly while controls declined. Because the control number fell, the gap between groups owes something to a drop on the comparison diet as well as to a gain on the fruit.

The two-point gap between the groups, 6.7% against 4.6%, is the central result of the trial, and the paper reports it as a significant difference in the primary outcome. Burton-Freeman said small, nutrient-dense additions may support heart health without the need for strict rules or major dietary overhauls, a framing that fits a study built around adding foods rather than removing them.

Eighty-two adults and a calorie-matched control diet

The trial enrolled 82 adults aged 25 to 60 who had prediabetes and a body mass index between 25 and 35, in the overweight or obese range. Participants were generally healthy non-smokers with no major chronic conditions and no specialized diets. They followed calorie-controlled plans modeled on typical American eating patterns for eight weeks in a two-group parallel design.

The intervention group added one medium Hass avocado and one cup of fresh mango each day. The control group received carbohydrate-based foods with equivalent calories, so any difference could not be put down to simply eating more. Researchers prepared and supplied meals covering 75% of each participant’s estimated daily calorie needs, and participants chose the rest themselves. Prediabetes is common, and the university release cites Centers for Disease Control and Prevention figures of one in three Americans, about 98 million people.

The control arm shapes how the result should be read. Participants in that group ate carbohydrate-based foods with matching calories, so the trial compares added fruit with added starch rather than with no addition at all. Weight did not change in either group, which rules out weight loss as the explanation for the vascular difference over eight weeks.

Blood pressure, kidneys and what did not change

Secondary results were mixed. Among men, central blood pressure in the control group rose by an average of 5 mmHg while it fell by about 1.9 mmHg in the avocado-mango group, and diastolic readings improved particularly in men. Estimated glomerular filtration rate, a kidney measure, also improved. The fruit group ate more fiber, vitamin C and monounsaturated fat.

Cholesterol, blood glucose and inflammation markers were largely unchanged relative to controls, and neither body weight nor total calorie intake shifted significantly. For people with prediabetes, the lack of a glucose effect is worth stating plainly: the benefit reported here is vascular, not a lowering of blood sugar.

The release gives rough nutrient figures for context. Three-quarters of a cup of mango supplies about 2 grams of fiber, or 7% of the daily value, and half of its vitamin C requirement at 50% of the daily value. A 50-gram serving of avocado, about a third of a medium fruit, adds 3 grams of fiber, 6 grams of unsaturated fat and 250 milligrams of potassium. The trial used a whole avocado and a full cup of mango, larger portions than those reference servings.

Industry funding and the limits of eight weeks

The study was supported by an unrestricted grant from the National Mango Board and the Hass Avocado Board. The university release states the boards had no role in the design or findings, but both organizations exist to promote the fruit, and readers should weigh the result accordingly.

The researchers acknowledge the trial lasted only eight weeks, so it cannot show whether the effect persists. It enrolled a narrow group, adults with prediabetes who were overweight or obese, and it measured risk indicators rather than heart attacks or strokes. It also did not test whether eating both fruits together beats either one alone, leaving the avocado-versus-mango question open.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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