The potato ranks in third place when it comes to the most commonly consumed food crops worldwide. For reproductive-aged women, this is not a good thing. Compared to women who rarely eat spuds, women who consume the most servings of potatoes before becoming pregnant have higher rates of gestational diabetes, suggests a National Institutes of Health (NIH) study.

The movie star of the vegetable world is rich in vitamin C, potassium, dietary fiber, and some phytochemicals, the researchers explain. Yet taters also contain large amounts of rapidly absorbable starch, so unlike other veggies, they can have detrimental effects on your glucose metabolism. In fact, high consumption of potatoes is linked to an increased risk of type 2 diabetes, due to high levels of blood sugar (glucose).

Because of this, the researchers of the current study wondered, Are potatoes also linked to a higher risk of gestational diabetes? This form of diabetes is a common pregnancy complication. And, gestational diabetes not only causes high blood sugar levels in the mother but it can lead to future health problems for both mother and child.

A research team from the NIH and Harvard University evaluated more than 15,000 women taking part in the Nurses’ Health Study II. Every four years, participants filled out a questionnaire on foods they had eaten during the previous year. The women reported how often they consumed baked, boiled, or mashed potatoes, fries or potato chips, by checking off an amount in the range of "never" to "six or more times a day."

Results of the Survey

Crunching the numbers, the researchers discovered women who ate more potatoes had a higher risk of gestational diabetes than those who ate fewer potatoes.

During 10 years of follow-up, the research team documented 854 incident gestational diabetes cases among 21,693 singleton pregnancies. After adjusting for age and other factors, the researchers calculated the relative risks of developing diabetes during pregnancy. Women who ate one serving of potatoes were 1.2 times more likely to develop gestational diabetes compared to those who ate less than a serving per week; women who ate 2 to 4 servings were 1.34 times more likely; and those who ate more than 5 servings were 1.62 times more likely. 

The researchers say more study is needed as their results do not prove conclusively that potato consumption directly leads to gestational diabetes. However, they've made their case.

Approximately 35 percent of American women between 19 and 50 years old consume potatoes daily, the researchers say. To reduce their risk of gestational diabetes, women should consider swapping potatoes for other vegetables, legumes, or whole grains. 

Source: Bao W, Tobias DK, Hu FB, Chavarro JE, Zhang C. Pre-pregnancy potato consumption and risk of gestational diabetes mellitus: prospective cohort study. BMJ. 2016.