New study shows red raspberries may help with glucose control in people with pre-diabetes

A study released today from the Illinois Institute of Technology shows the benefits of including red raspberries in the diet of individuals with pre-diabetes and insulin resistance.

According to the Centers for Disease Control and Prevention (CDC), an estimated 34 percent of American adults, around 84.1 million in all, had prediabetes in 2015. Patients with prediabetes are at higher risk for a number of conditions—including developing type 2 diabetes, cardiovascular disease and Alzheimer's disease.

The study, published in Obesity, investigated the effects of red raspberries in a group of people at-risk for diabetes who were overweight or obese and presented with prediabetes and insulin resistance. A metabolically healthy control group was also included in the study for reference.

Using a randomized, controlled, acute study design, 32 adults between the ages of 20-60 years had their blood tested over a 24-hour period after eating breakfast on three separate days. The three breakfast meals were similar in calories and macronutrients, but differed in the amount of frozen red raspberries—one meal contained no raspberries, one contained one cup of raspberries and one contained two cups of raspberries.

The results showed that as the amount of raspberry intake increased, individuals at risk for diabetes needed less insulin to manage their blood glucose. When two cups of red raspberries were included in the meal, glucose concentrations were lower compared to the meal with no red raspberries. The data suggests that simple inclusion of certain fruits, such as red raspberries with meals, can have glucose lowering benefits with indications of improvements in insulin responses. These effects are particularly important for people who are overweight or obese with pre-diabetes.

"People at risk for diabetes are often told to not eat fruit because of their sugar content. However, certain fruits—such as red raspberries—not only provide essential micronutrients, but also components such as anthocyanins, which give them their red color, ellagitannins and fibers that have anti-diabetic actions," said Britt Burton-Freeman, Ph.D., director, Center for Nutrition Research at Illinois Tech. "For people who are at risk for diabetes, cardiovascular disease and other health risks, knowing what foods have protective benefits and working them into your diet now can be an important strategy for slowing or reversing progression to disease."