Blueberries are rich in a variety of nutrients, including:
- vitamin C
- vitamin E
- vitamin K
One cup of fresh blueberries contains about:
- 84 calories
- 22 grams of carbohydrate
- 4 grams of fiber
- 0 grams of fat
In fact, the American Diabetes Association (ADA) calls blueberries a diabetes superfood. While there’s no technical definition of the term “superfood,” blueberries are packed with vitamins, antioxidants, minerals, and fiber that promote overall health. They may also help prevent disease.
For people living with diabetes, blueberries may help with glucose processing, weight loss, and insulin sensitivity. Read on to learn more about the benefits of blueberries for diabetes.
Glycemic index (GI) measures the effects of carbohydrate-containing foods on your blood sugar level, also called blood glucose level.
The GI index ranks foods on a scale of 0 to 100. Foods with a high GI number raise blood glucose levels more quickly than foods with a medium or low GI number. GI rankings are defined as:
- Low: 55 or less
- Medium: 56–69
- High: 70 or more
The glycemic index of blueberries is 53, which is a low GI. This is about the same as kiwi fruit, bananas, pineapple and mango. Understanding the GI of foods, as well as the glycemic load, can help people with diabetes plan their meals.
Glycemic load (GL) includes portion size and digestible carbohydrates along with GI. This gives you a more complete picture of a food’s effect on blood sugar by measuring:
- how quickly a food makes glucose enter the bloodstream
- how much glucose per serving it delivers
Like the GI, the GL has three classifications:
- Low: 10 or less
- Medium: 11–19
- High: 20 or more
One cup of blueberries with an average portion size of 5 ounces (150 g) has a GL of 9.6. A smaller serving (100 g) would have a GL of 6.4.
By comparison, a standard-sized potato has a GL of 12. This means a single potato has nearly twice the glycemic effect of a small serving of blueberries.
Blueberries might aid in the efficient processing of glucose. A University of Michigan study on rats found that feeding the rats powdered blueberry lowered abdominal fat, triglycerides, and cholesterol. It also improved fasting glucose and insulin sensitivity.
When combined with a low-fat diet, the blueberries also resulted in lower fat mass as well as lower overall body weight. Liver mass was also reduced. An enlarged liver is linked to insulin resistance and obesity, which are common features of diabetes.
More research is needed to determine the effects of blueberries on glucose processing in humans.
According to a 2010 study published in The Journal of Nutrition, obese adults with prediabetes improved insulin sensitivity by drinking blueberry smoothies. The study suggested that blueberries can make the body more responsive to insulin, which may help people with prediabetes.
Since blueberries are low in calories but high in nutrients, they may help with weight loss. For people who are overweight or obese, eating a healthy balanced diet that includes fruits such as blueberries may help prevent diabetes and improve overall health.
A 2015 study of 118,000 people over 24 years concluded that increasing fruit consumption — specifically berries, apples, and pears — results in weight loss.
The study suggested that this information could offer guidance for the prevention of obesity, which is a primary risk factor of health conditions such as diabetes.
Although more studies are needed to determine the biological effect of blueberries, some research suggests that eating blueberries can help people lose weight and improve insulin sensitivity. As such, blueberries could be beneficial for people with diabetes. Speak with your doctor or dietician for more information on eating a healthy diet for diabetes.