Should women limit potato consumption before pregnancy?

Thursday, September 01, 2016

 

Pre-pregnancy potato consumption linked to risk of developing diabetes during pregnancy

Women who eat more potatoes before pregnancy are more likely to develop gestational diabetes (i.e., the form of diabetes that occurs during pregnancy), a new study suggests.

The study was first-authored by Dr. Wei Bao, a new faculty in the UI Department of Epidemiology and a previous postdoc fellow at the National Institutes of Health (NIH). Dr. Bao is also a member of the UI Obesity Research and Education Initiative (OREI) and the Fraternal Order of Eagles Diabetes Research Center (FOEDRC).

Potatoes are one of the most commonly consumed crops in the world. The Dietary Guidelines for Americans continue to include potatoes in the vegetable food group and encourage consumption. However, previous studies suggest that potatoes may have a detrimental effect on blood glucose levels due to their high starch content. Gestational diabetes is a common pregnancy complication that affects around 9% of all pregnancies in the United States. Gestational diabetes has both short-term and long-term health risks for the mothers and children. The association between potato consumption and risk of gestational diabetes remains unknown until the present study.

Teamed up with researchers from NIH and Harvard University, Dr. Bao analyzed data from 15,632 women in the Nurses’ Health Study II over a 10-year period (1991-2001). The women had no history of gestational diabetes or chronic diseases before the index pregnancy. Consumption of potatoes and other foods was assessed every four years. Gestational diabetes was ascertained from self-reports of a physician diagnosis, which was previously validated by medical records.

They found that higher total potato consumption was significantly associated with an increased risk of gestational diabetes. Though the detailed mechanisms for the observed association remain to be understood, the researchers pointed out the high starch content with high glycemic index as a possible explanation. As a result, high consumption of potatoes can result in a sharp rise in blood glucose concentrations after a meal putting stress on pancreatic islet cells.

Substituting potatoes with other vegetables, legumes, or whole grain foods might lower the risk 

The researchers also estimated the effect of substituting of total potatoes with alternative, healthier foods. They found that substitution of two servings per week of total potatoes with the same amount of other vegetables, legumes, and whole grain foods was significantly associated with a lower risk of GDM: 9% lower risk for other vegetables, 10% for legumes, and 12% for whole grain foods.

The authors cautioned, however, that because their study was an observational study rather than an intervention study, their results do not prove the cause and effect relation that potato consumption directly leads to gestational diabetes.

These findings were published in the scientific journal BMJ (the British Medical Journal).