A simple Mediterranean-style diet in pregnancy does not reduce the overall risk of adverse maternal and offspring complications, but has the potential to reduce weight gain in pregnancy and the risk of gestational diabetes, according to a clinical trial led by Queen Mary University of London and the University of Warwick.
The results, published in the journal PLOS Medicine and funded by Barts Charity, show that having a Mediterranean-style diet (including 30g of mixed nuts per day and extra virgin olive oil) led to a 35 per cent lower risk of developing diabetes in pregnancy, and on average 1.25 Kg less weight gain in pregnancy, compared to those who received routine antenatal care.
The study suggests a Mediterranean-style diet could be an effective intervention for women who enter pregnancy with pre-existing obesity, chronic hypertension or raised lipid levels.
The ESTEEM study involved 1,252 women at five UK maternity units (four in London, including hospitals at Barts Health NHS Trust and St George’s University Hospitals NHS Foundation Trust, and one in Birmingham).
Multi-ethnic inner-city pregnant women with metabolic risk factors, including obesity and chronic hypertension, were randomised to either receive routine antenatal care or a Mediterranean-style diet in addition to their antenatal care. The diet included a high intake of nuts, extra virgin olive oil, fruit, vegetables, non-refined grains and legumes; moderate to high consumption of fish, small-moderate intake of poultry and dairy products; and low intake of red meat and processed meat; and avoidance of sugary drinks, fast food, and food rich in animal fat.
Despite the improvements in gestational diabetes and pregnancy weight gain, there was no improvement in other important pregnancy complications such as high blood pressure, pre-eclampsia, stillbirth, small for gestational age foetus, or admission to a neonatal care unit.
The participants in the Mediterranean-style diet group reported better overall quality of life than those in the control group and reduced bloatedness in pregnancy, but there was no effect on other symptoms such as nausea, vomiting or indigestion.
When the data from the study was combined with published data from a Spanish study involving 874 pregnant women on a Mediterranean diet, the team observed a similarly large reduction in gestational diabetes (a 33 per cent reduction), but no effect on other outcomes.
The work was carried out at Barts Research Centre for Women’s Health, based at Queen Mary University of London, funded by Barts Charity.
The study has limitations including its reliance on participant feedback for measuring adherence to the intervention, without use of objective biomarkers to measure nutritional intake. The team also only obtained information on dietary intake in about 40% of participants in both groups, which limits the interpretation of dietary intake data.
Research paper: Wattar B, et al. (2019). Mediterranean-style diet in pregnant women with metabolic risk factors (ESTEEM): a pragmatic multicentre randomised trial. PLOS Medicine; http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002857