Should you avoid white vegetables?

Last Saturday I was at a rural Georgia Farm Festival and I bought a bag of potatoes from a local farmer (photo of my purchase to the left). As I carried the 5-pound bag to my car, a stranger approached me wagging her finger at me. She said, “You shouldn’t eat those. I stopped eating potatoes years ago because white vegetables are horrible and you might as well pour sugar down your throat.”  I was stunned by her comment on many levels. First, when did it become acceptable for a stranger to give out nutrition advice? Second, she was just plain wrong.

A recent paper (executive summary available for free at http://advances.nutrition.org/content/4/3/318S.full.pdf) published a roundtable discussion convened on the campus of Purdue with leading nutrition experts. The topic of the roundtable and the summary was, “White vegetables: A forgotten sources of nutrients.”  As nutritionists, we often tell our clients to choose a colorful diet but maybe we should have emphasized that white vegetables are healthy, too, and certainly are not devoid of nutrients. One of the experts cited in the paper reminded us that white vegetables contain important nutrients like vitamins C and D, potassium, calcium, and dietary fiber, and color is not an accurate indicator of these nutrients. In addition to potatoes, other white vegetables include onions, cauliflower, mushrooms, and turnips and if we only used color as a guide to choosing our veggies we would miss some key nutrients.

Only 2-3% of Americans get the recommended intake of potassium and potatoes are one of our best sources of this important mineral. Higher potassium intakes are associated with lower blood pressure and the DASH diet, a meal plan designed to lower blood pressure, contains many potassium-rich foods, including potatoes. Potatoes are naturally low in sodium and high in potassium; a healthy combination.

Potatoes are also a good source of dietary fiber and not just in the skin. The flesh of the potato has soluble fiber, the kind of fiber that helps to lower blood cholesterol levels.

As for the comment that potatoes=sugar, well, that is a reference to the glycemic index; a measure of how a fixed amount of a carbohydrate in a food affects blood sugar. Potatoes have a higher glycemic index than other vegetables but that doesn’t mean they are the same as eating sugar. Most of use eat potatoes as part of a meal and the other foods in the meal can alter or lower the glycemic response of a single food.

I am going to prepare my potatoes by roasting them with a drizzle of olive oil and dried rosemary for a delicious side dish. Oh, and by the way, I saw the woman who admonished me later on at the festival eating hot dogs and, you guessed it, a bag of potato chips!