Q&A by David Richards, D.C., M.D.
Do you recommend that diabetics avoid white potatoes?
I certainly do not. I encourage my diabetic patients to eat freely of baked, steamed, microwaved, or boiled potatoes of any variety (prepared without added salt, oil, or sugar) as part of a healthy diet that also includes fruits, raw and cooked vegetables, whole grains, and legumes.
The idea that white potatoes are problematic for diabetics stems partly from the concept of the glycemic index, and partly from the inaccurate way that potatoes have been categorized in some scientific studies.
The glycemic index measures the extent to which a food raises blood sugar levels after it is eaten.1 Because white potatoes have been characterized as having a high glycemic index, it is often assumed that they can worsen diabetes. However, the glycemic index has not been found to be a useful concept when devising optimal diets for diabetics.2,3 One of the major problems with the glycemic index is its variability; not only do blood sugar responses to similar foods differ between individuals, they can vary significantly in the same person on different occasions.4 A recent review of the scientific literature conducted by the American Diabetes Association concluded that there is little difference in blood sugar control between “low-glycemic index” and “high-glycemic index” diets.5 For this reason, in their most updated guidelines, the American Diabetes Association has deleted a statement suggesting benefit from the glycemic index.6
Studies that have associated white potatoes with worsening of blood sugar control included the consumption of fried potato products (i.e., French fries and potato chips) under the category of “potatoes.”7,8 It is, therefore, not surprising that potato intake led to worse health outcomes when studied in this way. However, when processed potatoes are excluded, there is no evidence that white potato consumption is linked to diabetes or other negative effects on health. On the contrary, when looking at the nutritional makeup of a potato, it becomes clear that it can be included in a health-promoting eating plan. While I don’t want people to become obsessed with the nutrient composition of the foods that they are eating, it is important to know that potatoes rank high in a number of areas.
For example, a medium-sized Russet potato:(9, 10, 11)
- has only 168 calories
- is an excellent source of vitamin C
- has no sodium, fat, or cholesterol
- is a good source of potassium and vitamin B6
- has 8 percent of the daily requirement for fiber
- has one of the highest overall antioxidant activity among vegetables (more than broccoli)
- is a source of “resistant starch,” which improves insulin sensitivity
I can assure you that our epidemic of diabetes is not a result of Americans eating too many baked or boiled potatoes. Furthermore, there is no evidence that in people already diagnosed with diabetes, white potato consumption (when consumed without added oil, salt, or sugar) worsens control of blood sugar levels. Diabetes (as well as obesity and metabolic syndrome) are due to eating a diet composed of foods that are calorically dense, low in fiber and other beneficial nutrients, and high in fat. Potatoes have none of these attributes and should be regarded as an excellent food for both diabetics and nondiabetics. Labeling white potatoes as unhealthy because of the problems associated with French fries and potato chips is akin to claiming that apples are not wholesome because eating apple pie causes weight gain.
1. Monro JA, Shaw M. Glycemic impact, glycemic glucose equivalents, glycemic index, and glycemic load: definitions, distinctions, and implications. Am J Clin Nutr. 2008 Jan;87(1):237S-243S.
2. Wolever TM, Gibbs AL, Mehling C et al. The Canadian Trial of Carbohydrates in Diabetes (CCD), a 1-y controlled trial of low-glycemic-index dietary carbohydrate in Type 2 diabetes: no effect on glycated hemoglobin but reduction in C-reactive protein. Am. J. Clin. Nutr. 87(1), 114–125 (2008).
3. Ma Y, Olendzki BC, Merriam PA et al. A randomized clinical trial comparing low-glycemic index versus ADA dietary education among individuals with Type 2 diabetes. Nutrition 24(1), 45–56 (2008).
4. Vega-López S, Ausman LM, Griffith JL, Lichtenstein AH. Interindividual variability and intra-individual reproducibility of glycemic index values for commercial white bread. Diabetes Care 30(6), 1412–1417 (2007).
5. Wheeler ML, Dunbar SA, Jaacks LM et al. Macronutrients, food groups, and eating patterns in the management of diabetes: a systematic review of the literature, 2010. Diabetes Care 35(2), 434–445 (2012).
6. American Diabetes Association. Evidence for changes in recommendations. Standards of Medical Care in Diabetes – 2012. http://www.care.diabetes%20journals.org/content/suppl/2012/01/06/35%20Supplement_1.S11_DC2/EvidenceTable
7. Halton TL, et al. Potato and French fry consumption and risk of type 2 diabetes in women. Am J Clin Nutr. 2006;83(2):284-290.
8. Mozaffarian D, et al. Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. N Engl J Med 2011; 364:2392-2404.
9. USDA National Nutrient Database for Standard Reference, Release 25. http://ndb.nal.usda.gov/ndb/foods/show/3069?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=russet+potato
10. Wu X, Beecher GR, Holden JM, et al. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. Journal of Agricultural and Food Chemistry. 2004; 52:4026-4037.
11. Murphy MM, Douglass JS, Birkett A. Resistant starch intakes in the United States. J Am Diet Assoc. 2008;108:67-78.
David Richards, D.C., M.D., is a chiropractor and board certified internist currently practicing internal medicine in St Louis, MO. His philosophy is to provide the highest quality, evidence-based health care with as little medical intervention as possible.
Reprinted from the magazine, Health Science, Winter 2013 https://www.facebook.com/notes/national-health-association/do-you-recommend-that-diabetics-avoid-white-potatoes/10151143052782614