COPENHAGEN, DENMARK — Studies reviewed by University of Copenhagen researchers did not provide “convincing evidence” to suggest an association between intake of potatoes and risks of obesity, type 2 diabetes or cardiovascular disease. French fries, however, may be associated with increased risks of obesity and type 2 diabetes, according to the review in the Aug. 1 issue of The American Journal of Clinical Nutrition.
Researchers deemed 13 studies as eligible. Five were related to obesity, seven were related to type 2 diabetes, and one was related to cardiovascular disease.
The researchers cited a prospective pooled cohort study that showed increasing potato consumption by one serving per day of all types of potatoes combined was associated with a mean body weight gain of 0.58 kilograms (1.28 lbs) over a four-year period. Comparing the different types of potato preparations, boiled, baked and mashed potatoes were associated with the least weight gain at 0.26 kilograms and french fries were associated with the most weight gain at 1.52 kilograms.
“This result may have been due to the higher energy density of french fries than of baked, boiled and mashed potatoes,” the University of Copenhagen researchers said. “However, because these were observational studies, we could not completely exclude confounding because of an unhealthy lifestyle that was possibly related to intake of french fries.”
The researchers from the University of Copenhagen said to interpret the results on the obesity studies cautiously because no long-term randomized controlled trials were found.
Among the seven prospective observational studies involving type 2 diabetes, two studies observed a positive association, three studies showed no association, and two studies showed a negative association. A positive association with type 2 diabetes and french fries was shown in all three studies that distinguished preparation type.
The researchers noted that while potatoes generally are considered to have a high-glycemic index, they also provide potassium, vitamin C, phosphorus, magnesium, folate, dietary fiber and polyphenols.A single eligible study investigated cardiovascular disease. No association between intake of potatoes and risk of ischemic stroke was shown when the highest quintile of intake was compared with the lowest quintile. The study did not specify how the potatoes were prepared.