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According to modern dietary standards, it is recommended to consume at least 400 grams of vegetables and fruits per day. Vegetable servings should include non-starchy and starchy vegetables. Meanwhile, there is confusion regarding “healthy” and “harmful” carbohydrates, and people are increasingly avoiding starchy foods altogether. Scientists from the Albert Einstein Medical College have studied the possible consequences of replacing starchy vegetables with grains.
Distinguishing Starchy Vegetables and Grains
Both types of products contain complex carbohydrates, and in the case of whole grains, they also provide fiber. However, most of their similarities end there. Primarily, the difference lies in the presence of vital vitamins, macro- and micronutrients.
It’s tempting to think of all carbohydrate foods as interchangeable. But these foods are categorized within different food groups for a reason – perhaps most importantly, they tend to have vastly different vitamin and mineral contents.
Keith Ayoob, EdD, RDN, Associate Professor Emeritus, Albert Einstein College of Medicine
A medium-sized potato with skin (5.3 oz) and two slices of whole grain bread have similar energy values, approximately 110 versus 160 calories, respectively. The disparities in nutrient content are more significant.
- Potassium:
- Potatoes: 15% of Daily Value (DV);
- Whole Grain Bread: 3% DV;
- Vitamin C:
- Potatoes: 30% DV;
- Whole Grain Bread: 0% DV;
- Vitamin B6:
- Potatoes: 10% DV;
- Whole Grain Bread: 8% DV;
- Iron:
- Potatoes: 6% DV;
- Whole Grain Bread: 9% DV;
- Dietary Fiber:
- Medium-sized Potato: 8% DV;
- Whole Grain Bread: 14% DV.
The low phosphorus content in potatoes makes iron more bioavailable than iron in plant-based products with higher phytate content. Phytate is the salt of phytic acid, the primary storage form of phosphorus in seeds and present in all plant cells. Additionally, the high vitamin C content in potatoes enhances iron absorption.
Research Overview
Dr. Ayob analyzed two one-day menu models to assess the nutritional contribution of starchy vegetables and grain products to the daily diet.
For comparison, a ~2000-calorie menu was utilized based on the Dietary Guidelines for Americans 2020-2025 and in accordance with the “Food Patterns” from the USDA. The model included hash browns (fried potato pancakes, a traditional American dish) with a slice of whole grain bread for breakfast. Baked potatoes with white rice were served for dinner.
Results
All starchy vegetables in the model were replaced with grains. As a result, potassium decreased by 21%, vitamin B6 by 17%, vitamin C by 11%, and dietary fiber by 10%. At least half of the grains were whole grains.
Changes in dietary fiber and potassium content raised concerns among scientists. According to the conclusion of the Dietary Guidelines Advisory Committee for 2020-2025, these nutrients are a “public health concern.” Additionally, currently, 90% of women and 97% of men do not meet the recommendations for the necessary amount of dietary fiber.
Researchers’ Conclusions
Scientists emphasize that potatoes do not substitute other valuable non-starchy vegetables and are not interchangeable with them. According to their statements, currently, only one in ten adults meets the medical recommendations regarding the quantity of vegetables in their diet.
Researchers assert the need for further studies due to the limitations of existing data. Additional simulations over a more extended period will help further explore the dietary consequences of avoiding both starchy vegetables and carbohydrate-rich foods.
Thanks to modern technology and diagnostics, scientists are revisiting recommendations for healthy eating. Recent research has indicated that a lack of dairy products can lead to iodine deficiency in women. It’s worth noting that in the USA, the development of dietary guidelines for the United States for 2025-2030 is currently underway.
