Potatoes linked to gestational diabetes, Harvard research
Researchers from Eunice Kennedy Shriver National Institute of Child Health and Human Development and Harvard University tracked 15,632 women who were part of the Nurses’ Health Study II and who became pregnant over a 10-year period (1991-2001).
They had no previous gestational diabetes or chronic disease before pregnancy.
Consumption of potatoes and other foods was assessed every four years and cases of gestational diabetes were ascertained from self-reports of a physician diagnosis of GDM, which was validated by medical records.
Over the 10 year follow-up period, the team identified 21,693 single pregnancies of which 854 were affected by gestational diabetes.
After taking account of other risk factors for gestational diabetes such as age, family history of diabetes, physical activity, overall diet quality, and BMI, they found that higher total potato consumption was significantly associated with an increased risk of gestational diabetes.
However, substituting two servings of potatoes a week with other vegetables, legumes, or whole grain foods was significantly associated with a 9-12% lower risk.
The authors point out that potatoes have a high glycaemic index compared with other vegetables, so can trigger a sharp rise in blood sugar levels, and this could be one explanation for the findings.
Potatoes are one of the world’s most commonly consumed foods. US dietary guidelines continue to include potatoes in the vegetable food group and encourage consumption, though previous studies suggest that potatoes can have a detrimental effect on blood sugar levels due to their high starch content.
Gestational diabetes is a common pregnancy complication that has long term health risks for both mothers and babies, but the association between potato consumption and risk of gestational diabetes remains unknown.
The researchers acknowledge study limitations and because of the observational nature of the work no definitive conclusions can be drawn however they ultimately conclude that higher levels of potato consumption before pregnancy are associated with greater risk of gestational diabetes.