Sweet potatoes are yellow or orange tubers that taper to a point on both ends. One type has a paler, thin, light yellow skin with a pale yellow flesh that is not sweet and has a dry, crumbly texture similar to a white baking potato. The other type has a darker, thicker, orange to reddish skin with a sweet, deep orange flesh with a moist texture. This darker type is often mistakenly called “yam”.
A true yam is a tuber of Dioscorea batatas, a tropical vine. Yams are in no way related to the sweet potato. Yams are generally sweeter than sweet potatoes, and can also be much larger.
While both are great sources of fiber and other nutrients, there are differences in terms of nutrition. Both are assumed to be rich in vitamin A due to their orange flesh, an indicator of foods rich in beta-carotene, a precursor to vitamin A. One hundred fifty grams (g) of sweet potatoes (about one cup diced) has 18,866 IU of vitamin A, well over three times the daily requirement for vitamin A. Here’s a surprise: the same amount of yams (150 g) has only 207 IU of vitamin A, only about 4% of the daily requirement.
That same 150 g of yams have 1,224 milligrams (mg) of potassium, over one third of the daily requirement. Compare that with 150 g of sweet potatoes, which has 448 mg of potassium. Yams have more vitamin C than sweet potatoes with 25.6 mg (43% of the daily requirements) compared to only 3.2 mg in sweet potatoes. Yams have 600 micrograms of manganese, 30% of the daily requirements and twice the amount of sweet potatoes. Yams also pack more calories and total carbohydrates than sweet potatoes. One hundred fifty grams of yams have 177 calories and 42 g total carbohydrate compared to sweet potatoes, with 114 calories and 27 g total carbohydrate.
Whether you are eating a sweet potato or a yam, you are getting fiber plus many great nutrients and phytonutrients. Serve your potatoes with a variety of other vegetables, including leafy greens, to be sure you’re getting all your daily nutritional requirements.
I love roasted sweet potatoes (or yams?). What is your favorite way to prepare sweet potatoes or yams?