You probably already know that blueberries’ high levels of antioxidants are but one among many of their health benefits; now comes news that they may help fight belly fat.

WebMD is reporting on a new study presented at Experimental Biology 2009, that shows rats given a diet high in blueberries lost fat around their abdomen, along with other health benefits like improved glucose regulation and lower cholesterol, even when their diet is otherwise unhealthy.

Abdominal fat is linked to diabetes and heart disease.

"Some measurements were changed by blueberry even if the rats were on a high-fat diet," says University of Michigan researcher E. Mitchell Seymour, in a news release.

The results imply that blueberries may alter how we process and store glucose or carbohydrate for energy, say the researchers, reducing both diabetes and heart disease risks.

"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," University of Michigan researcher Steven Bolling, says in the release.

The study involved researchers feeding rats bred to be obese either a low-fat or high-fat diet with added whole blueberry powder or carbohydrates as 2% of their total diet.

The rats fed blueberries had lower cholesterol, better insulin sensitivity and glucose control – and less abdominal fat – after three months on the diet.

Whether the rats were fed a low- or high-fat diet the health benefits were apparent if they took the blueberry powder, although the benefits were biggest with those who consumed a low-fat diet.

In results that should shock no one, rats on the low-fat diet lost the most fat mass and total body weight compared to those on the high-fat diet, alongside the other heart health benefits.

More research is yet needed to replicate these results in humans, but a related study at the same conference shows men with risk factors for heart disease showed minor improvements in glucose and insulin control after drinking wild blueberry juice for three weeks.