Type 2 diabetes patients can eat potatoes without blood sugar control issues, study shows

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MELBOURNE, Australia — While sugar and potatoes may not sound like they have much in common, patients with Type 2 diabetes are often told to avoid them. Researchers in Australia say the long-held belief is eating these vegetables makes it hard to control blood sugar levels. Their study however finds this may not be the case at all. A clinical trial reveals eating potatoes, along with other food, will not negatively impact a diabetes patient’s levels.

The team from Australian Catholic University reports potatoes are among the foods which have a high Glycemic Index (GI). Eating these foods at night can be particularly risky, when blood sugar levels tend to spike.

Researchers examined 24 adults with type 2 diabetes who either had a dinner with one of three different versions of skinless white potatoes or basmati rice — a low GI carbohydrate food. After continuous monitoring of their blood levels, the results reveal GI is an inaccurate measure of glycemic response (GR). Study authors add participants eating potatoes with their meal actually had a better “nocturnal” GR than those eating rice.

“There are limitations using the GI of single foods and their acute effect on blood glucose when trying to determine their influence on long-term health indices, particularly in people with type 2 diabetes as individual foods are rarely consumed in isolation but are more likely to be eaten with other foods as part of mixed meals,” says primary investigator Dr. Brooke Devlin, PhD in a university release.

“It’s rare that people eat foods in isolation, and findings from this study demonstrate how other factors, such as the time of day or food pairings, need to be considered when investigating the glucose release of mixed meals in individuals with Type 2 diabetes.”

No change awake or asleep

Type 2 diabetes patients ate the same breakfast and lunch during the experiment, but then had four dinner options. The test meals featured either skinless white potatoes which were either boiled, roasted, or boiled then cooled and reheated. The control meal gave participants rice.

The group cycled through all of these meals with a nine-day break in between each. Researchers took blood samples right after each meal and again every 30 minutes for two hours. The study also monitored each diabetes patient as they slept to track glucose levels throughout the night.

The results find a person’s GR does not change whether they’re eating rice or a high-GI food like potatoes. The Australian team adds overnight GR readings stayed more stable after eating potatoes with dinner compared to a low-GI alternative.

“These findings are contrary to that of observational research and traditional dietary guidance that has led some to believe potatoes are not an appropriate food choice for people with Type 2 diabetes,” Devlin adds in a media release. “Our study shows high GI foods, like potatoes, can be consumed as part of a healthy evening meal without negatively affecting GR — and while delivering key nutrients in relatively few calories, which is essential for people with Type 2 diabetes.”

Can Type 2 diabetes patients eat potatoes every day?

Devlin and her team note the study only focuses on the GR effects of one meal. The meal size was also larger than what is typically recommended for T2D patients, but was still in line with the country’s normal eating patterns. Researchers will also need to determine the long-term impact of adding potatoes to a diabetic diet.

“Potatoes are a vegetable that is sustainable, affordable and nutrient-dense, and thus, they can play an important role in modern diets irrespective of metabolic health status,” the study authors conclude.

The study appears in the journal Clinical Nutrition.