A diet first designed to help treat high blood pressure has shown some promising results in improving pregnancy outcomes in women with gestational diabetes.

Gestational diabetes (GDM) is a form of diabetes that occurs during pregnancy, affecting around 8 percent of all pregnancies. The high blood sugars from the diabetes can result in the developing baby growing too large, causing birth complications. Following delivery, the baby can also experience low blood glucose levels caused from being removed from the glucose-rich environment of the mother. The mother also suffers a much higher lifetime risk of developing type 2 diabetes.

The first steps in treating GDM are lifestyle changes, including changes to diet where needed. There is some evidence that a lower glycaemic index (GI) diet may help with GDM, but overall there is not a lot of solid evidence for what are the best dietary changes to make.

One novel dietary pattern that has been considered as a candidate for treating GDM is the Dietary Approaches to Stop Hypertension (DASH) diet. First designed to treat high blood pressure, it has also been positively tested in type 2 diabetes and metabolic syndrome.

A DASH diet is rich in fruits, vegetables, legumes and nuts, moderate in low-fat dairy and low in animal proteins, refined grains and high sugar foods. The DASH diet is also considered a low GI diet so it appears on the money for a positive recommendation for treating GDM.

Involving 52 women living in Iran diagnosed with GDM, a 4-week trial looked at how a DASH diet or a balanced nutrient profile control diet fared as their pregnancy progressed to delivery. Each woman was randomly allocated to one of the two diets and adherence to their allocated diet was checked by weekly phone interviews and self-completed diet diaries. The average gestational age at the start of the diet was close to 26 weeks.

What the study found

For such a small trial, the results appeared quite impressive. Twelve of the 26 women (46%) in the DASH diet group required a caesarean section compared to 21 out of 26 (81%) in the control diet group. The number of women that eventually required insulin therapy to manage their GDM showed a similar difference with just 6 (23%) in the DASH group compared to 19 (73%) in the control group.

The average weight of infants born to mothers on the DASH diet was significantly lower at 3.2 kg versus 3.8 kg in the control diet group. This was a positive outcome as GDM is a major risk factor for large birth weight infants.

What it all means

This first use of a DASH style diet to treat GDM has shown some impressive results. If such results can be replicated in other clinical trials, then a DASH dietary pattern could be on the menu soon for all women with GDM.