Can Blackberries Help to Reduce Blood Sugar?

Blackberries are high in soluble fiber and can help lower your blood sugar.


A diet rich in fruits such as blackberries is healthy for many reasons, but one of the most important is the potential impact they have on your blood sugar. Besides being a generally low-calorie food packed with vitamins, minerals and healthy phytonutrients, blackberries are extremely rich in soluble fiber, a type of dietary fiber that can help keep your blood sugar in a healthy range.

Blood Sugar

Your body converts carbohydrate nutrients into glucose, an essential energy source that travels in your blood to reach all your tissues and organs. Insulin, a hormone made by your pancreas, moves glucose into your cells, helping lower its blood level after a meal. But when you consume sugary, carbohydrate-rich foods, your blood sugar can rise quickly, reaching high levels and remaining high for long periods. This puts stress on your pancreas to produce large amounts of insulin. Over time, consistently high blood sugar levels can raise your risk of Type 2 diabetes, which develops when you no longer produce insulin or your body becomes insensitive to the insulin you do make.

Soluble Fiber

Although dietary fiber provides no nutrition, it helps your body in many ways. Two types of fiber exist -- insoluble, which moves through your digestive tract unchanged, and soluble, which forms a gel when mixed with fluid in your stomach. Soluble fiber can slow the absorption of carbohydrate nutrients from your food, producing a gradual increase in blood sugar after you eat and preventing spikes in blood sugar that require large amounts of insulin. All berries generally contain abundant fiber and are especially rich in soluble fiber. Blackberries provide relatively large amounts of both types of fiber: 3/4 cup of berries contains 2 grams of soluble fiber and 4 grams of insoluble fiber. The 2010 Dietary Guidelines for Americans recommend that adult men and women consume about 38 and 25 grams of total fiber, respectively, each day.


Many clinical research studies have examined the possible benefit of soluble fiber in helping manage blood sugar. For example, in a study published in "Diabetes in Research and Clinical Practice," healthy subjects consumed a diet containing either modest or high levels of soluble fiber for 3 months. Those that consumed a diet high in soluble fiber had a 12 percent decrease in their average blood sugar compared to the other group. Another study involved human subjects with diabetes of varying severity who consumed differing amounts of soluble fiber. The study, published in the "Journal of Nutritional Biochemistry," found that those who consumed the most soluble fiber experienced a 29 percent reduction in their average blood sugar levels and had lower blood insulin, suggesting that consuming soluble fiber reduced the demand on their bodies for the hormone.

Eating Blackberries

Choose firm, plump berries that are free of external moisture and show no evidence of mold, and look for berries with a uniform dark purple color since these have the highest content of healthy phytonutrients. Blackberries are naturally sweet and require no added sugar, making them especially healthy. At breakfast, add them to your cereal or yogurt, or consume them as a side serving of fresh fruit. At lunch or dinner, add blackberries to a fresh salad or combine them with steamed green beans or other vegetables to provide a sweet yet tart taste. You can also add blackberries to homemade baked goods, reducing the sugar in recipes since they add sweetness of their own.

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