Dietary patterns and insomnia symptoms Original paper

In this meta-analysis of observational studies, healthier diets tended to be associated with a reduced risk of insomnia symptoms.

Whether dietary patterns are associated with insomnia symptoms.

A total of 591,223 participants (average ages of 14–80).

A meta-analysis of 37 observational studies (29 cross-sectional studies, 5 cohort studies, and 3 case-control studies) was performed. Twelve studies were conducted in Iran, 7 in the United States, 3 in Spain, 2 in China, 2 in Greece, 2 in Japan, and 1 each in Sweden, Mexico, Poland, Italy, Turkey, Korea, Iran, France, and Finland.

Almost all of the studies assessed dietary intake using a food frequency questionnaire. A variety of assessment tools were used to measure insomnia symptoms, but the majority of studies used the Insomnia Severity Index. Data comparing the participants with the highest adherence to a dietary pattern to those with the lowest adherence were obtained from the included studies.

The following associations were reported:

• Higher adherence to a Mediterranean diet was associated with 14% lower odds of insomnia symptoms (based on 10 studies).
• A higher-quality diet was associated with 34% lower odds of insomnia symptoms (based on 6 studies).
• A higher-glycemic-index diet was associated with 16% higher odds of insomnia symptoms (based on 2 studies).

Adherence to the Dietary Approaches to Stop Hypertension Diet was not associated with insomnia symptoms (based on 4 studies) .

All of the studies included in the analysis for diet quality used a different scoring system, including the Healthy Eating Index 2015, the Alternative Healthy Eating Index 2010, the Diet Quality Index, the Spanish Healthy Eating Index, and the Healthy Diet Indicator. Thus, what exactly is meant by a “higher quality diet” isn’t entirely clear, although diets that score high on all of these systems share some common principles, such as being rich in whole grains, legumes, and fruits and vegetables and low in ultraprocessed foods.