Glucometer, Potatoes
Glucometer, Potatoes

Does sweet potato reduce blood sugar?

Diabetes is a chronic health condition that is characterised by the accumulation of glucose (sugar) in the blood.


The food we eat is broken down into glucose (a form of sugar) by the body and released into our bloodstream.

The body then produces a chemical called insulin to help move the glucose from the blood into the muscles and other tissues of the body for use as energy.

In diabetes, the insulin produced by the body is either not enough or the body cells do not respond to it appropriately, leading to excess glucose in the bloodstream.

Over time, that can cause serious health problems such as heart disease, vision loss and kidney disease.

Sweet potato is a root vegetable that has a sweet taste as the name suggests.

The ‘brix’ level (the level of sweetness) varies between the different varieties which is partly accounted for by the place where they were grown.

The various varieties of sweet potato are characterised by different flesh colours with varying phytochemical composition.

Globally, there are over 400 varieties.

Some of the varieties in Ghana are  “Apomuden” – deep orange, “Bohye” – light orange, “Diedi”– purple flesh” and “Obari”– white flesh.

Nutrtional Value (Per 100g)

Nutrient        Quantity
Water         77.28g
Energy        359KJ
Protein        1.57g
Fat            0.05g
Ash            0.99g
Carbohydrate        20.12g
Fiber            3.00g
Calcium        30.00g
Iron            0.61mg
Magnesium        25.00mg
Phosphorus        47.00mg    
Potassium        337mg
Sodium        55.00mg
Vitamin C         2.40mg
Vitamin A         709mcg
Pantothenic acid    0.80mg
Vitamin B-6        0.21mg

Sweet potato’s anti-diabetic properties are due to its antioxidant and nutrient content.

They contain antioxidants and are also rich sources of vitamins A and C, which both have antioxidant properties.

Antioxidants help to remove free radicals (harmful by-products of metabolism which can cause disease) from circulation.

Several studies have shown that there is an increased formation of free radicals and a decrease in antioxidant potential in diabetics, the antioxidant and free radical scavenging ability of sweet potato is suggested to improve insulin sensitivity, resulting in blood sugar control.  

Additionally, the high potassium and magnesium level of sweet potato enhances the production of insulin. 

High fiber

It has a high fibre content, which is further increased when eaten with the skin.

Fibre is the part of plant food which cannot be digested.

It protects the body in many ways, including controlling the rate of carbohydrate digestion into glucose, which slows down the rate at which the glucose enters the blood and reduces the blood sugar spikes after eating.

Resistant starch

The starch content has been described as particularly suitable for resistance starch formation.

Resistant starch is a type of carbohydrate that travels through the small intestine without fully digesting, due to a resistance to enzymatic breakdown in the small intestine.  


It, therefore, enters the colon of the large intestine barely digested, where it is fermented and serves as food (prebiotic) for the good bacteria in the small intestine.  

These good gut bacteria in turn produce short-chain fatty acids that play a key role in reducing blood sugar.

Resistant starch in sweet potato can be formed by cooking it and allowing it to cool before eating.

The starch granules in sweet potato gelatinise during cooking and retrograde into a more crystalline nature which becomes resistant to enzymatic digestion when it is cooled.


Consuming sweet potato by cooling after cooking, therefore, can help to control blood sugar.

Diabetic patients should, however, consult a registered dietitian to determine safe quantities they can eat.

How to eat it

Sweet potato can be enjoyed with or without the skin and can be baked, boiled, roasted or steamed.

Their natural sweetness pairs well with many different seasonings, and they can be enjoyed in both savory and sweet dishes.


Excessive consumption of sweet potatoes may lead to Vitamin A toxicity (skin rashes and headaches), bloating, stomach pain and diarrhea.

The writers are with the Department of Dietetics, 
College of Health Sciences, 
University of Ghana.

E-mail: [email protected]

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