A new study shows rats who ate a diet rich in blueberries lost abdominal fat -- the kind of fat linked to heart disease and diabetes -- as well as experienced other health benefits like lowered cholesterol and improved glucose control even if their diet wasn’t otherwise heart-healthy.
"Some measurements were changed by blueberry even if the rats were on a high-fat diet," researcher E. Mitchell Seymour, MS, of the University of Michigan’s Cardioprotection Research Laboratory, says in a news release.
Researchers say the results suggest that antioxidant-rich blueberries may change how the body stores and processes glucose or sugar for energy, thereby reducing the risk of both heart disease and diabetes.
"The benefits of eating fruits and vegetables have been well researched, but our findings in regard to blueberries show the naturally occurring chemicals they contain, such as anthocyanins, show promise in mitigating these health conditions," researcher Steven Bolling, MD, of the University of Michigan, says in the release.
Blueberries Boost Heart Health
In the study, presented at Experimental Biology 2009, researchers fed rats bred to become obese either a high-fat or low-fat diet enriched with whole blueberry powder or carbohydrates as 2% of their total diet.
After 90 days, the rats fed blueberries had less abdominal fat, lower cholesterol, and improved glucose control and insulin sensitivity. The latter two factors are markers of how well the body processes sugar for energy and are related to diabetes risk.
These health benefits of blueberries were evident in rats fed both high- and low-fat diets enriched with the blueberry powder. But the benefits were greatest among those who ate a low-fat diet.
In addition to the other heart health benefits of blueberries, those fed the low-fat blueberry diet also lost body weight and fat mass compared to those on the high-fat diet.
Although more research is needed to confirm these results in humans, a related study presented at the same conference showed that men with risk factors for heart disease who drank wild blueberry juice for three weeks seemed to experience slight improvements in glucose and insulin control.