According to the latest statistics available from the World Health Organization (WHO), about 9% of adults had diabetes in 2014. Diabetes was the primary cause of 1.5 million deaths in 2012. More than 80% of diabetes deaths take place in developing countries.
Type 2 diabetes comprises 90% of individuals with diabetes around the world. Obesity and physical inactivity are linked to risk factors for type 2 diabetes. The body's ineffective use of insulin results in type 2 diabetes.
"Potato food consumption should be reduced for people with elevated risk of developing diabetes or insulin resistance. Healthy foods such as vegetables, fruits, whole grains, and nuts, rather than potatoes, should be encouraged for the prevention of type 2 diabetes," said first author Isao Muraki, MD, PhD, of the Osaka Center for Cancer and Cardiovascular Disease Prevention, Japan, and Harvard TH Chan School of Public Health, Boston, Massachusetts.
The study analyzed data from three US studies on 70,773 women from the Nurses' Health Study conducted between 1984 and 2010, a total of 87,739 women from the Nurses' Health Study II (1991-2011), and as many as 40,669 men from the Health Professionals Follow-Up Study (1986-2010).
Participants did not have cancer, cardiovascular disease, or diabetes at the beginning of the study. Researchers examined potato consumption using validated food frequency questionnaires. They also observed the 4-year change in potato consumption. They spotted type 2 diabetes using self-report and confirmed it with a questionnaire.
The study results showed that individuals with a higher consumption of potatoes - baked, boiled, mashed, or french fried - had a greater risk of type 2 diabetes.
Persons who had less than two to four servings of potatoes per week had a 7% increased risk of type 2 diabetes. Also, participants who ate seven or more servings per week had 33% increased risk compared to those who consume less than one serving per week.
People who consumed french fries had a higher risk of type 2 diabetes than those who had mashed, baked or boiled potatoes.
Participants who improved their potato consumption over time - particularly french fries - had an increased risk of diabetes. For every three portions per week increase, they had a 4% increased risk of diabetes compared with those who ate the same amounts of potatoes over time.
Estimations showed that replacing three servings per week of potatoes - regardless of type - with whole grains would decrease the risk of type 2 diabetes by 12%.
Whether to hold potatoes as a vegetable in dietary recommendations has recently been a point of contention in the United States and the United Kingdom, with the two countries coming to contradictory conclusions.
MyPlate, the current nutrition guide issued by the United States Department of Agriculture, recognize potatoes to be a "healthful vegetable."
In contrast, the UK national food guide, the Eatwell plate, lists potatoes as a cereal, according to background information in the article.
"Although potatoes are considered a vegetable in the US Guideline of Healthy Eating, potatoes should not be regarded as an essential component of a healthful diet. These data support the notion that potatoes should be considered a source of carbohydrates like grains, especially refined grains, rather than vegetables," said Muraki.
"Potatoes contain a large amount of starch and a relatively small amount of fiber, vitamins, minerals, and polyphenols. Lower quality and quantity of carbohydrate is associated with a higher risk of type 2 diabetes," he added.
Researchers acknowledge that these results may not extend to other ethnic and demographic groups because study participants were healthcare professionals of European ancestry.
References:1. Isao Muraki, Eric B. Rimm, Walter C. Willett, JoAnn E. Manson, Frank B. Hu and Qi Sun
Published online before print December 17, 2015, doi: 10.2337/dc15-0547