Superfood to control blood sugar levels? Here’s how diabetics can add sweet potatoes to their diet

It is advisable to have sweet potatoes boiled for about 30 minutes. It lowers glycemic index (GI) to about 46. Leave the skin on. When boiled and eaten with skin, it provides fibre which controls blood glucose levels, says Aishwarya Kumbhakoni, Consultant Dietician, Diabetes, Kokilaben Dhirubhai Ambani Hospital Mumbai

Sweet potato (Ipomoea Batatas) is a starchy tuber that grows on the roots of the plant (Source: Pixabay)

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Sweet potato (Ipomoea Batatas) is a starchy tuber that grows on the roots of the plant and, compared to potato fries and wedges, can be a better source of carbohydrates. It is native to the Central and South America region. It is one of the most consumed carbohydrate-rich sources in the world. There are almost over 400 varieties of sweet potatoes grown worldwide. In many developing countries, it is preferred as a staple dish along with other carbohydrate-rich grains such as rice, wheat and maize (corn).

What are the health benefits of consuming sweet potatoes?

Red and purple varieties of sweet potatoes are rich in Vitamin A in the form of β- carotene. They are an important source of manganese (an essential trace mineral), which helps improve bone health and carbohydrate metabolism in diabetes. They contain a mixture of soluble and insoluble fibre, beneficial for gut health and building satiety, and, therefore, contribute to weight loss. They are also a rich source of antioxidants known to be anti-inflammatory and play a protective role in cancer. They are one of the sources of vitamin B6, which is beneficial in pregnancy and other body functions. They are rich in vitamin C, which boosts immunity. Moreover, sweet potatoes are rich in iron.

Can people with diabetes consume sweet potatoes?

The quantity and quality of carbohydrates significantly impacts blood glucose levels. The Glycemic Index (GI) of foods is a way of classifying carbohydrate-containing foods according to their ability to raise blood glucose levels. People with diabetes should prefer food with low (≤ 55) to moderate GI (56- 69). Foods with high GI value (≥ 70) should be avoided in the diet.

Sweet potatoes are rich in carbohydrates (100 gm of sweet potato has approximately 24 gm of carbohydrates). The consumption of sweet potatoes could increase blood glucose levels if taken along with other carbohydrate-rich sources. Therefore, you need to follow carb-counting and cut out other carb sources. Besides, you need to limit the portion size of the sweet potato itself and combine that with protein or fibre to keep blood glucose levels in check. It is itself rich in fibre, that keeps you full for a longer time, adds bulk to your diet and delays release of glucose in the blood. It has resistant starch, which takes time to digest, boosts gut bacteria and stabilises blood glucose levels.

There are some cooking techniques which can lower the GI of sweet potatoes. It is advisable to have boiled sweet potatoes (GI 46) with a longer boiling time (about 30 minutes). Leave the skin on. When boiled and eaten with skin, it provides approximately 4 grams of fibre for every 100 grams.

Peeled-roasted (GI 82), peeled-baked (GI 94), or fried preparations (GI 76) have a relatively high GI, making them an unsuitable choice of consumption for persons with diabetes. According to Harvard TH Chan School of Public Health, “boiling sweet potatoes retains more beta-carotene and makes the nutrient more absorbable than other cooking methods such as baking or frying. Up to 92 per cent of the nutrient can be retained by limiting the cooking time, such as boiling in a pot with a tightly covered lid for 20 minutes. Cooking with the skin on further helps to minimize leaching of nutrients including beta-carotene and vitamin C.”

What is the take-home message?