Sweet potatoes play a very important role in African nutrition and some people may consider them a second staple food. The colour of sweet potato flesh varies with variety. You may know the common white, yellow and orange fleshed ones. However, you may also find grey or purple fleshed sweet potatoes. Sweet potato colour is associated or connected to its nutritional and sensory acceptability. In my village people only growth the white and yellow fleshed ones, rarely the orange fleshed sweet potatoes. Whilst it depends on location and what people are used too, people should try sweet potatoes with different flesh colours. This can help you make up for the micronutrient deficiencies that are common with cereal diets. Most sweet potato varieties are rich in sugars, resistant starch, vitamins, minerals, bioactive proteins, polyphenols, vitamin C and coumarins. All these phytochemicals can contribute to your good health in a well-balanced diet.
Sweet potato flesh colours and their health benefits.
Orange fleshed sweet potatoes
Orange fleshed sweet potatoes are among the most common sweet potato varieties among nutritionist. This is mainly due to their ability to fight vitamin A deficiency among low income populations. Vitamin A deficiency is among one of the most common micronutrient deficiency. According to a 2018 study, UNICEF has identified vitamin A deficiency to be the cause of illness and death in over 140 million children. And in most cases it is responsible for poor eyesight, night blindness and poor adaptation to dark conditions.
Now, the problem is that most sources of vitamin A like meat are beyond the rich of many low income families. And for vegetarians meat, one of the richest sources of vitamin A is a no go area. Now, an orange fleshed sweet potato is not really expensive, or costly. At the same time it can help you and your family fight vitamin A deficiency. Many people love orange fleshed sweet potatoes due to their sweetness, nutrition as well as appealing colour. But, how does it do that?
How orange sweet potatoes solve vitamin A deficiency
Well, it’s very easy. Your orange fleshed sweet potatoes as well as other orange fleshed foods are rich in yellow orange compounds called carotenoids. These carotenoids give the sweet potatoes their yellowish orange colours. Now, these carotenoids are very unique compounds, because they have the ability to act as vitamin A. In nutrition, we say that carotenoids have provitamin A activity. Having provitamin A activity means that when you eat the carotenoids in orange fleshed sweet potatoes, they will be converted to vitamin A in your body. And all this means you can use these sweet potatoes to improve your vitamin A status. The vitamin A you gain from this sweet potato promotes good health by boosting your immune system, as well as improving your skin and eye health.
Most foods will have their carotenoids when you boil or heat them during the cooking process. However, orange fleshed sweet potatoes have the best carotenoid retention after cooking in foods.
What else can orange fleshed sweet potatoes give you?
Orange fleshed sweet potatoes are not only special for their ability to improve your vitamin A intake. They are actually also known to be a cheap source of other antioxidant and beneficial compounds. Such compounds have many physiological benefits which include:
- Chronic inflammation fighting
- Cancer and genetic mutation protection
- Oxidative stress protection and fighting
- Diabetes and cardiovascular disease prevention properties.
These include non provitamin A carotenoids and anthocyanins. These compounds do not have provitamin A activity, but it doesn’t make them any less healthy. Because they are known for their powerful antioxidant and health promoting properties. It has been shown that many healthful compounds in orange sweet potato plants help in protecting your body from oxidative damage. Compounds in orange fleshed sweet potatoes help in protecting you from inflammation and oxidative stress based health problems such as cardiovascular diseases, cancers and inflammatory diseases. In addition eating orange fleshed sweet potatoes provide you with many other nutrients and health promoting factors that can promote good health.
Purple fleshed sweet potato varieties
Orange fleshed sweet potatoes are rich in both carotenoids and anthocyanins. Both groups of compounds are responsible for the colour of the sweet potatoes. In yellow-orange fleshed sweet potatoes, orange coloured carotenoids are predominant. On the other hand, in purple fleshed sweet potatoes anthocyanins are the predominant phytochemicals. And like carotenoids, they also come packed with health promoting properties.
Purple fleshed sweet potatoes are rich sources of purple coloured compounds called anthocyanins. And many studies have shown that anthocyanins have valuable nutraceutical properties. Now, nutraceuticals are compounds that you can find in food. These compounds usually serve both a nutritional value as well as medicinal value. So, they have many health benefits when you eat foods rich in them.
What do we get from purple flesh sweet potatoes?
Anthocyanins have been shown to be able to promote good health when taken in good health. Studies show that eating foods rich in anthocyanins like purple fleshed sweet potatoes has preventative effects on chronic diseases. These include, diabetes, cancer, age related neurodegenerative decline as well as cardiovascular diseases. And in one 2013, study, sweet potatoes with purple flesh were shown to reduce colorectal cancer risks. This was done through arresting and preventing cell proliferation as well as killing cancer cells.
Anthocyanins have been associated with preventative and protective effects against chronic inflammation and oxidative stress induced chronic diseases. Some studies show that anthocyanins present in purple fleshed sweet potatoes may have many health benefits as well as protective and preventative properties against diseases. These properties include:
- Reduced risks of age related macular degeneration.
- Anticancer and cancer protective activities.
- The ability to fight and protect you from oxidative stress and chronic inflammation.
- Reduced risks of cardiovascular diseases and heart problems.
- Antiulcer activities.
Anthocyanins in sweet potatoes have some of the strongest antioxidant activities among food pigments. This may help you in reducing oxidative stress and related chronic diseases. So, purple fleshed sweet potatoes are not just tubers, they are health promoting tubers.
Read: (PDF) Flesh Colour Diversity of Sweet Potato: An Overview of the Composition, Functions, Biosynthesis, and Gene Regulation of the Major Pigments (researchgate.net)
A sweet potato is a nutritionally rich food crop that has powerful bioactive compounds that promote good health. There are many different sweet potato varieties, with different flesh colours. And each specific flesh colour signals a different heal promoting nutrient. Orange fleshed sweet potatoes are rich in carotenoids. These sweet potatoes have more carotenoids than anthocyanins. On the other hand, purple fleshed sweet potatoes are in anthocyanins which also promote good health. Now the only thing you have to know is that the deeper the colour the higher the phytonutrient content. And lastly, you can use sweet potatoes with different flesh colours to promote good health and improve your diet quality.