There is a common debate that yams and sweet potatoes are the same. But they are not. Not only are they different in appearance, but they also taste different. This confusion occurs typically because you can buy sweet potatoes as yams in superstores or in canned form. So if you think you just ate yams, check again.
Nutrition in Yams vs. Sweet Potatoes
Even though both yams and sweet potatoes are stem tubers, they have different nutrition values. When comparing 100 grams of boiled or baked sweet potatoes and yams, calories found in sweet potatoes are fewer than in yams. Sweet potatoes also contain a higher percentage of Vitamin C and 3 times more beta-carotene, converted to Vitamin A.
Sweet potatoes can provide your body with the daily recommended dosage of Vitamin A, which is essential for the immune system. However, yams have higher fiber content, a lower glycemic index, and lesser sugars than sweet potatoes. While sweet potatoes are richer in Vitamin A, yams have higher amounts of various forms of Vitamin B. 
What’s the Difference?
Both yams and sweet potatoes are tuber vegetables but have some significant differences that set them apart. They differ in appearance since sweet potatoes are long and tapered in size while yams are slightly bigger. Sweet potatoes have smooth skin, but yams have rough and tough skin.
The flesh of both vegetables is also different. Sweet potatoes have sweeter flesh which can vary in color from orange to purple and white. Yams can have white, purple, pink, or yellow flesh, which is comparatively dry and starchy than sweet potato flesh. They first found sweet potatoes in South and Central America, while Yams were found in Asia and Africa.
Yams vs. Sweet Potatoes Taste
Yams and sweet potatoes are versatile vegetables, and you can cook them differently for various textures. While sweet potatoes have a sweeter taste, yams are neutral and have an earthy touch in their taste. The mildly sweet taste of yams usually disappears when you add spices and seasonings, and they take on that flavor. It is necessary to cook yams since they are toxic when raw.
Yams can be roasted, boiled, or fried, depending on the dish you want to make. In African culture, they mash yams and add it to soups and gravies. Many people also dry out yam flesh to grind it into powder which you can add to boiling water to make a starchy paste. This is known as Amala, and you can serve this along with dishes and soups.
The sweet taste of sweet potatoes is heightened when you cook them. If you want to enhance and caramelize the sweet part, baking sweet potatoes will do that. Many people use natural sugars like molasses and maple syrup with sweet potatoes to enhance and complement the sweet flavor of the vegetables.
Yams vs. Sweet Potatoes for Diabetics
Studies suggest that both yams and sweet potatoes can be good for diabetic patients. White-skinned yams and sweet potatoes help decrease insulin resistance since they have glucose and lipid metabolism in the system.
Caiapo is a type of sweet potato with white skin which shows improvement in the symptoms of type 2 diabetes. It increases insulin sensitivity while decreasing fasting blood sugar levels and LDL cholesterol levels termed bad cholesterol. However, further research is a need on humans to see the effects of sweet potatoes on type 2 diabetes. 
Benefits of Yams vs. Sweet Potatoes
Yams and sweet potatoes have different health benefits. Yams contain diosgenin, which controls and prevents osteoporosis and rheumatoid arthritis symptoms. A study conducted on mice showed that mice fed yam extracts for 90 days showed a decrease in inflammation levels and lower pain levels. Human studies is a need to see the effects on human cases of inflammation and pain. 
When diosgenin was extracted from yams and given to mice, it decreased their cholesterol and LDL levels within 4 weeks. Researchers claim that diosgenin could have similar effects on humans, but research is a need in this field.
Yams are also great to improve hormonal imbalance since diosgenin is for producing estrogen and progesterone. Women eat yams to help with menopause, but there is no proof that diosgenin can naturally be converted to hormones in the body.
Sweet potatoes also have multiple health benefits, mainly helping with Vitamin A deficiency. Lack of Vitamin A can lead to damage to the eyes permanently. It is high in beta-carotene, which converts to Vitamin A in the body. 
Sweet potatoes also help control blood glucose levels and LDL cholesterol by increasing insulin sensitivity. Sweet potatoes are full of antioxidants and protect cells from oxidative damage. Carotenoids in sweet potatoes help prevent stomach, kidney, and breast cancers. Purple sweet potatoes have the highest level of antioxidants.
Yams vs. Sweet Potatoes Disadvantages
Despite being popular in diets, these tuber vegetables can also cause issues. Sweet potatoes are high in compounds known as oxalates which tend to increase the risk of kidney stones in people. If you are already facing kidney and liver issues, you should avoid eating sweet potatoes since they can cause permanent failure.
Consuming too many sweet potatoes may lead to Vitamin A toxicity due to the high amounts of Vitamin A found in it. It may also increase potassium levels in the body, damaging the heart. 
Yams need to be cooked since they contain toxins that could be fatal if consumed raw. Moreover, yams should not be consumed by pregnant and lactating women since they can have fatal effects on children.
Yams and sweet potatoes should be consumed in moderation since they have many beneficial properties to improve health. However, if consumed more than required, they can negatively affect the body. They’re versatile and nutritious and can be added to various dishes or eaten alone with seasonings.
However, they’re both different with different textures and tastes. You should know the difference between the 2 before buying either.
Disclaimer: This article is only a guide. It does not substitute the advice given by your own healthcare professional. Before making any health-related decision, consult your healthcare professional.
Editorial References And Fact-Checking
- Bahado-Singh, P. S., Wheatley, A. O., Ahmad, M. H., Morrison, E. Y., & Asemota, H. N. (2006). Food processing methods influence the glycaemic indices of some commonly eaten West Indian carbohydrate-rich foods. The British journal of nutrition, 96(3), 476–481.
- Kusano, S., & Abe, H. (2000). Antidiabetic activity of white skinned sweet potato (Ipomoea batatas L.) in obese Zucker fatty rats. Biological & pharmaceutical bulletin, 23(1), 23–26. https://doi.org/10.1248/bpb.23.23
- Son, I. S., Lee, J. S., Lee, J. Y., & Kwon, C. S. (2014). Antioxidant and Anti-inflammatory Effects of Yam (Dioscorea batatas Decne.) on Azoxymethane-induced Colonic Aberrant Crypt Foci in F344 Rats. Preventive nutrition and food science, 19(2), 82–88. https://doi.org/10.3746/pnf.2014.19.2.082
- West K. P., Jr (2003). Vitamin A deficiency disorders in children and women. Food and nutrition bulletin, 24(4 Suppl), S78–S90. https://doi.org/10.1177/15648265030244S204