May 22, 2012

Potatoes and Your Nutrition

Have you ever wondered about the difference between a sweet potato and a yam? Are they the same? Is one healthier than the other? And what about potatoes? Should you be eating them? Let's talk about this topic via the latest reader question.


Dear Tiffany the Dietitian,
I’m confused about potatoes, sweet potatoes and yams. I’ve read that sweet potatoes are “much more nutritious” than potatoes, but those same articles include pictures of things that look more like yams. And I recently read an article saying the yams aren’t terribly nutritious, which was even more confusing. Leaving aside the sugary, fatty or salty toppings that sometimes accompany these foods, can you please explain the nutritional profile of potatoes, sweet potatoes and yams so I can figure out how these food fit into our diet? -- Jen


Thanks for your question, Jen. Seems like since the Atkins diet has waned in popularity, now potatoes and other starchy vegetables are back in business. To which I say, Hoooray! Potatoes, sweet potatoes and yams are all healthy foods to eat; they're plants and therefore contain plant-nutrients (called phytochemicals), which may reduce the risk of cancer. However - while all healthy - potatoes, sweet potatoes and yams have slightly unique nutritional profiles.

Let's talk definitions first. According to the Academy of Nutrition and Dietetics, what we typically call "yams" in the US (the more orange vegetable) are actually sweet potatoes. Real yams are rarely grown here and are more common in Central and South American, Asia and Africa. Yams can be white or yellow, even purple or pink. They have less vitamin A than sweet potatoes, but are loaded with fiber, potassium and vitamin C.

Sweet potatoes have the highest amount of Vitamin A out of the three, while also containing fiber, potassium and other vitamins and minerals. Traditional (white) potatoes offer a good source of fiber, vitamin C and potassium, but lack vitamin A. 

The take-home point is that potatoes, yams and sweet potatoes are all nutritious foods. Vitamin for vitamin, mineral for mineral, I would say sweet potatoes win the battle. But variety is important, so we typically eat all three kinds of potatoes at my house. I serve it as a "starch" side dish, since potatoes are quite high in carbohydrates.

Steaming, baking or roasting with a little olive oil, salt and pepper usually does just fine, but when I'm in the mood for something different, I like these recipes:


  1. So let me get this straight--the orange things called labeled "yams" (or sometimes "garnet yams") at the grocery store (and on the right in your picture at the top) are really sweet potatoes?

    And the the things on the left in your picture at the top (labeled "sweet potatoes") are also sweet potatoes?

    Thanks for this post, btw!

    1. YES! A little confusing, right? The more orange sweet potatoes contain more vitamin A. The definitions are a bit strange, but at least we can easily conclude that they're all healthy - when cooked in a healthy way - and can be incorporated into our diets without the slightest shred of guilt :)