September 2013 Issue

Don’t Judge a Vegetable by its Lack of Color

“Eat the rainbow.” You’ve heard nutrition professionals say it over and over again when advising the public about making healthy choices in produce. What they’re really emphasizing is variety—it is best to eat an array of colors in order to maximize nutrient intake. But, researchers are beginning to find that white vegetables often go overlooked, and color may not be the only indicator of nutritional quality. While the U.S. Department of Agriculture’s MyPlate recognizes two vegetable subcategories on the basis of color—green and red/orange—no distinction is given to white vegetables, even though they also appear to play an important role in the phytochemical rainbow.

White veggies have health benefits, too. In June 2012, a group of scientists met at Purdue University to address the common misconceptions and fallacies surrounding white vegetables. The scientists concluded that increasing the intake of white vegetables such as cauliflower, kohlrabi, onions, white mushrooms, and white potatoes can notably increase the consumption of key nutrients lacking in the American diet, such as potassium, magnesium and fiber.

Not only that, intake of white vegetables has been linked to a variety of health benefits, ranging from reduced inflammation and “bad” cholesterol levels to promoting heart health and cancer protection. 

Potatoes in particular. Many misguided efforts to reduce the consumption of “white foods”—such as white bread and white sugar—in recent years have given potatoes a bad name. However, potatoes should not be relegated to a category of low-nutrient foods. Potatoes, the most popular American vegetable, serves as an important source of vegetable intake as a whole. And when they are heated and cooled, such as in potato salad, potatoes provide a good source of resistant starch, a form of fiber that can aid in weight and blood sugar control. The humble potato (along with beans) gives you the most nutritional bang for your buck when it comes to potassium and fiber content compared to dark-green and deep-yellow vegetables, according to a study published in May of 2013. However, potatoes are moderately high in carbohydrates (1 small baked potato has 29 grams, about the same amount found in a medium bagel half), so should be consumed in moderation. 

—McKenzie Hall, R.D.