Is it time to challenge common beliefs? The ongoing debate about “good versus bad carbs” has long plagued consumers. However, new research published in Frontiers in Nutrition sheds light on the carbohydrates we should prioritize in our meals. Keith Ayoob, the study author and associate professor emeritus at Albert Einstein College of Medicine in the Bronx, explains, “It’s easy to think of all carbohydrate foods as interchangeable. However, these foods are grouped differently for a reason, particularly because they have varying vitamin and mineral contents.”
Ayoob’s study reveals that replacing starchy vegetables, such as potatoes, with grain-based foods like rice and whole-grain bread for just one day caused a significant decrease in essential nutrients. Specifically, there was a 21% drop in potassium, 17% reduction in vitamin B6, 11% decrease in vitamin C, and a 10% decline in fiber. Ayoob emphasizes, “It’s easy to think of all carbohydrate foods as interchangeable, but they are grouped differently for a reason.”
To illustrate his findings, Ayoob created two one-day menu models. The first model focused on starchy vegetables, including hash browns for breakfast and a baked potato for dinner. The second model replaced potatoes with whole wheat bread for breakfast and white rice for dinner. A comparison between starchy vegetables and grains showed that while grains tend to possess lower levels of potassium and vitamin C, they offer higher amounts of thiamine, zinc, and vitamin E. Ayoob notes, “Many starchy vegetables are excellent sources of potassium, with a medium-sized potato providing 15% of the recommended daily value. Replacing starchy vegetables with grains may widen the gap between recommended and actual potassium intakes.”
Furthermore, the study found that the substitution of grains for potatoes resulted in a meaningful decrease in fiber intake, highlighting the importance of including both starchy vegetables and grains in one’s diet. The Dietary Guidelines for Americans suggest that most adults should consume 5 cups of starchy vegetables each week. Examples of starchy vegetables include breadfruit, burdock root, cassava, corn, jicama, lima beans, lotus root, plantains, salsify, tapioca, turnips, water chestnuts, white potatoes, yams, and yucca.
Ayoob acknowledges the limitations of his study. It only included potatoes as the representative starchy vegetable and examined the effects over a single day. Conducting modeling with other starchy vegetables over a more extended period may yield different results. Ayoob stresses that starchy vegetables have distinct nutrient profiles compared to grain foods, and this should be taken into account in dietary guidance.
As is often the case in nutrition, Ayoob reminds us that balance, variety, and moderation are key. Although it may seem mundane, incorporating all types of vegetables and grains, both starchy and non-starchy, is crucial for meeting our nutritional needs, both macro and micronutrients alike.
