Mediterranean Diet and Metabolic Risk Factors in Pregnancy: Esteem Trial

The ESTEEM trial looked at whether the Mediterranean diet can decrease the chances of gestational diabetes and preeclampsia.

Women who are pregnant are at risk for developing complications that could put both their child and the mother in danger. These complications are very serious and include gestational diabetes, hypertensive disorders of pregnancy, and the increased risk of obesity. There are preventative measures that mothers can take that can reduce the risk of developing these conditions like lifestyle modifications, which include increasing exercise frequency; healthier eating; and stress management. 

There are various diet regimens that patients are recommended and placed on. The Mediterranean-style and DASH Diets are two of the main diets that are recommended to patients who are at an increased metabolic risk. Dietary Approaches to Stop Hypertension, or DASH, is a diet that is recommended by the National Heart, Lung, and Blood Institute (NHLBI) and its primary focus are to prevent or improve hypertension outcomes. Although DASH is recommended for anyone with a risk of developing hypertension, it is important to note that there is no clear consensus on the dietary recommendation for pregnant women with high metabolic risks, Bassel Al Wattar of Queen Mary University in London and his colleagues set out to perform a trial that would put the Mediterranean style diet to the test and to evaluate the effectiveness of the diet in pregnant women.

Using a multicenter, randomized trial, Al Wattar and his colleagues recruited women from 5 inner-city maternal units between September 2014 and February 2016. To be eligible, the women that were recruited were at least 16 years of age and less than 18 weeks into the pregnancy. Because the Mediterranean diet includes nuts and olive oil, the women who were recruited could not have an allergy to either substance. All women with pre-existing diabetes, gestational diabetes, CKD, or autoimmune disease were excluded from the trial. Once all the baseline measurements were obtained, the women in the trial were randomized into control or intervention groups. The ESTEEM intervention was the Mediterranean diet. There was 1 personalized session and 2 group sessions to guide the women on the techniques of the Mediterranean diet. The control group was given dietary guidelines per the UK National recommendations.

The primary outcome measures for this study combined the number of preeclampsia, stillbirth, gestational diabetes, and low birthweight incidence in each group. The criteria and eligibility of the different outcome measures are explained in detail in the article. Of the 3,421 women, 1,252 women were positive for metabolic risk and were randomized into either the control or intervention group. Many of the primary outcomes yielded insignificant results; this included preeclampsia, low birth weight rates, stillbirths, and admission to the neonatal unit. The only group outcome that yielded a significant result was that of the gestational diabetes assessment. There was a significant reduction in the odds ratio of developing diabetes (OR 0.65, 95% CI 0.47–0.91, p = 0.01).

Although the data of the trial yielded insignificant results for most of the primary outcome measures, it is important to note that the diet and lifestyle modifications are very difficult to implement, from a research point of view, and that the clash between culture and health may have made implementation and adherence difficult. The upside of this trial is the reduction in gestational diabetes in the mothers who received the intervention. The importance cannot be overstated and the prevention of just one pregnancy complication is worth investigating and celebrating.

Practice Pearls:

• Trial data on the Mediterranean diet in pregnant women is lacking and further research was needed
• Data yielded significantly decreased odds of developing gestational diabetes during pregnancy. All other endpoints were not significant.
• Although the endpoints did not show much significance, it is important to note that the decrease in one endpoint is still significant and worth celebrating.

Reference for “Mediterranean Diet and Metabolic Risk Factors in Pregnancy: Esteem Trial”:

Wattar, Bassel H. Al, et al. “Mediterranean-Style Diet in Pregnant Women with Metabolic Risk Factors (ESTEEM): A Pragmatic Multicentre Randomized Trial.” PLOS Medicine, vol. 16, no. 7, 23 July 2019, doi:10.1371/journal.pmed.1002857.

Usif Darwish, PharmD Candidate, Florida A&M University, College of Pharmacy & Pharmaceutical Sciences