Mediterranean diet in pregnancy: A recipe for reduced stress and improved sleep

By Tarun Sai LomteJun 4 2023Reviewed by Benedette Cuffari, M.Sc.

A recent study published in Nutrients evaluates the impact of a Mediterranean diet (MedDiet) intervention in pregnancy on maternal well-being, sleep quality, and stress.

Study: Effects of a Mediterranean Diet Intervention on Maternal Stress, Well-Being, and Sleep Quality throughout Gestation—The IMPACT-BCN Trial. Image Credit: Antonina Vlasova / Shutterstock.com

The health benefits of the MedDiet

The MedDiet has profound positive health effects, with randomized control trials (RCTs) demonstrating the contribution of the MedDiet to alleviate major cardiovascular events and improve cardiovascular profiles in persons at risk of cognitive decline, diabetes, cancer, and inflammatory disorders. There is also growing interest in the effects of the MedDiet on quality of life, mental health, and stress.

Anxiety and stress are common among pregnant individuals, with numerous mental disorders occurring before pregnancy and even changing during and after pregnancy.

Previous studies have reported the effectiveness of non-pharmacologic interventions (NPIs), such as biofeedback, mindfulness meditation, yoga, and exercise, in improving stress and other mental problems during pregnancy. Nevertheless, there is limited evidence on the effects of dietary approaches on these conditions during pregnancy. 

Structured MedDiet-based interventions can have potential benefits for pregnant individuals and their children. For example, a recent clinical trial reported that a MedDiet intervention was associated with a reduced incidence of perinatal complications and small neonates among pregnant subjects at a high risk of having small-for-gestational-age (SGA) neonates. However, the MedDiet's impact on individuals' well-being during pregnancy remains undefined. 

About the study

In the present study, researchers evaluate the effects of a structured MedDiet intervention during pregnancy on maternal stress, sleep, anxiety, quality of life, and mindfulness. The improving mothers for a better prenatal care trial (IMPACT) is an RCT that is being conducted at a large hospital in Barcelona, Spain.

Individuals were screened during their regular ultrasonography appointment in the second trimester for the risk of having an SGA neonate. Participants were randomized to three intervention arms, which included a mindfulness-based stress reduction program, MedDiet intervention, and usual care, with the current study assessing participants from the MedDiet intervention and usual care groups.

MedDiet subjects were instructed to consume more fresh fruits, legumes, whole-grain cereals, dairy products, vegetables, white meat, fish, and nuts and use olive oil for dressings and cooking. Controls received the usual care in pregnancy without any intervention. Subjects in either group did not receive advice or intervention on mental health, sleep quality, well-being, stress, or anxiety.

The primary outcome was the effect of the MedDiet intervention on maternal well-being, sleep quality, mindfulness, stress, and anxiety. At baseline and final assessment, a subset of participants underwent measurements of urinary cortisone, cortisol, and other related metabolites. The cortisone/cortisol ratio was calculated to assess the activity of 11β-hydroxysteroid dehydrogenase type 2.

Clinical and sociodemographic data of subjects were obtained. Subjects attended baseline and final visits with a dietician to assess their diets using food-frequency questionnaires, seven-day dietary registries, and MedDiet adherence scores. Participants completed lifestyle questionnaires on stress and anxiety, well-being, mindfulness, and sleep quality at enrollment and 34-36 gestational weeks.

MedDiet improves mental health and sleep quality in pregnant women

The study included 331 participants in the MedDiet intervention and 349 in the usual care group, with similar baseline characteristics observed between these groups. Perinatal and pregnancy outcomes were not significantly different between groups. Perceived stress, poor sleep quality, and anxiety increased in all participants throughout gestation.

MedDiet participants exhibited significantly lower perceived stress at the end of the intervention period as compared to controls. Likewise, MedDiet subjects had lower final anxiety scores than controls and improved sleep quality.

Approximately 20% of MedDiet subjects had poor well-being as compared to over 27% of controls. There were no significant differences in mindfulness scores between groups.

The 24-hour cortisone/cortisol ratio increased during gestation and was similar between groups; however, this increase was more pronounced among MedDiet subjects. Furthermore, MedDiet subjects had higher total cortisone concentration and percentage but lower 5β-tetrahydrocortisone/cortisone ratio at the final assessment than controls.

Conclusions

The MedDiet intervention led to a significant reduction in maternal stress and anxiety, with improvements in sleep quality and well-being among pregnant individuals at risk for an SGA newborn. However, the researchers could not estimate long-term dietary intake, including pre-pregnancy dietary patterns and changes during pregnancy.

Most subjects were ethnically White with middle or high socioeconomic status. As a result, these findings may not apply to other populations and should be considered preliminary. 

Given the growing significance of mental health contributions to pregnancy outcomes, the study findings may imply that pregnancy-adapted MedDiet could be a vital public health strategy.