Avocado and Mango Daily for 8 Weeks Improved Blood Vessel Function in Prediabetes Trial
About 98 million Americans live with prediabetes - a condition characterized by elevated blood glucose that has not yet crossed the clinical threshold for type 2 diabetes, but that carries substantially elevated cardiovascular risk. Dietary interventions that can improve vascular function in this population without requiring wholesale diet overhauls are of considerable practical interest. A randomized trial conducted at Illinois Institute of Technology now offers controlled evidence that a specific fruit combination may do exactly that.
The study, published in the Journal of the American Heart Association, enrolled 82 adults with prediabetes and found that those who ate one Hass avocado and one cup of fresh mango daily for eight weeks showed meaningful improvements in two markers of cardiovascular health - blood vessel function and diastolic blood pressure - compared with a calorie-matched control group. Neither group gained weight during the intervention.
Study design: controlled feeding over eight weeks
Participants were generally healthy adults aged 25 to 60 with prediabetes and overweight or obesity (body mass index 25-35 kg/m2), who were non-smokers, not on special diets, and free from major chronic conditions. The Avocado-Mango (AM) group received one medium Hass avocado and one cup of fresh mango daily, incorporated into meals and snacks. The control group received calorie-matched carbohydrate-based foods as replacements.
All meals provided 75 percent of participants' daily caloric needs and were prepared and distributed by the research team, ensuring consistency and compliance. Participants self-selected their remaining calories. The primary outcome was flow-mediated dilation (FMD), a non-invasive ultrasound measure of endothelial function - how well blood vessels dilate in response to increased blood flow, a reliable indicator of vascular health.
The vascular improvements in numbers
FMD increased to 6.7 percent in the AM group over eight weeks. In the control group, FMD declined to 4.6 percent. The difference is clinically meaningful: each one-percentage-point improvement in FMD is associated with reduced cardiovascular event risk in longitudinal studies, and the 2.1-percentage-point gap between groups represents a substantial divergence over a relatively short intervention.
Diastolic blood pressure improvements were observed particularly in male participants. Men in the control group experienced an average increase of 5 mmHg in central blood pressure. Men in the AM group experienced a reduction of approximately 1.9 mmHg - a difference of nearly 7 mmHg that, if sustained over time, would be clinically significant for cardiovascular risk.
The AM group also increased their intake of dietary fiber, vitamin C, and monounsaturated fat - nutrients associated with cardiovascular benefit - without corresponding increases in total caloric intake or body weight. Some kidney function markers, including estimated glomerular filtration rate, also improved in the AM group.
What the study did not show
No significant differences were found between groups in cholesterol levels, blood glucose, or markers of systemic inflammation. The study was eight weeks long, which limits conclusions about whether the vascular improvements would persist or accumulate with longer consumption. The participant population was specific - prediabetic adults with overweight or obesity - and the findings may not generalize to people without metabolic risk factors or to broader age ranges.
The nutrient combination driving the observed effects remains unclear. Avocados contribute monounsaturated fats, potassium, and fiber. Mangoes contribute vitamin C and additional fiber. Whether the combination is necessary for the observed benefit - or whether either fruit alone would produce equivalent results - was not tested in this trial design.
"This research reinforces the power of food-first strategies to help reduce cardiovascular disease risk, particularly in vulnerable populations like those with prediabetes," said principal investigator Britt Burton-Freeman, professor at Illinois Tech. "Small, nutrient-dense additions - like incorporating avocado and mango into meals and snacks - may support heart health without the need for strict rules or major dietary overhauls."
Funding context
The study was supported through an unrestricted grant from the National Mango Board and the Hass Avocado Board, neither of which had any role in study design or findings. Unrestricted industry funding in nutritional research is common and does not invalidate results, but readers should note the funding source when interpreting claims about the specific products involved.