Vegetarian diet linked to lower risk of insomnia, study suggests

By Dr. Sanchari Sinha Dutta, Ph.D.Dec 12 2023

A study published in the European Journal of Clinical Nutrition reveals that people following a vegetarian diet may have a lower risk of insomnia, a common sleep disorder.

Study: Plant-based dietary patterns and risk of insomnia: a prospective study

Background

Insomnia is a common sleep disorder characterized by difficulty falling and staying asleep for at least three nights per week for at least three months. The condition is associated with a higher risk of cardiovascular disease, stroke, abnormal blood lipid profile, diabetes, anxiety, and depression. In addition, insomnia can reduce the overall quality of life, cognitive functions, and work productivity and increase automobile accident risk.

Cognitive behavioral therapy and sedative-hypnotic drugs are two effective treatment options for insomnia. However, various disadvantages, such as accessibility, adherence, cost, risk of drug abuse, addiction, and withdrawal, potentially restrict the use of these treatments. This highlights the need to identify modifiable lifestyle factors to reduce insomnia risk.

Recent evidence indicates that adherence to the Mediterranean dietary pattern can improve sleep quality and reduce insomnia risk. A healthy dietary pattern is known to reduce inflammation and maintain gut microbial composition, which in turn can improve sleep quality.

In this study, scientists have investigated the relationship between plant-based dietary patterns and the risk of insomnia.

Study design

The study was conducted on a total of 5,821 participants from The Tzu Chi Health Study. This prospective cohort study recruited participants from the Tzu Chi population between 2007 and 2009 and followed up with them until 2018. All participants were advised to consume plant-based (vegetarian) diets and avoid smoking and drinking alcohol. Participants who avoided meat and seafood for over a year were considered vegetarians.

A healthful plant-based index (hPDI) was calculated to determine adherence to a healthy plant-based diet. A higher hPDI would represent higher intakes of healthful plant foods and lower intakes of both unhealthful plant foods and animal foods.

Incident cases of insomnia were obtained from the National Health Insurance Research Database (NHIRD). All participants were followed up via this database until the date of insomnia diagnosis, death, termination of enrollment in the NHI program, or the end of the study period (December 31, 2018), whichever came first. Appropriate statistical analyses were carried out to determine the association between plant-based diet and insomnia risk.

Important observations

A total of 5,821 Tzu Chi volunteers participated in the study, of whom about 29% were vegetarians and had higher hPDI scores compared to non-vegetarians.

The dietary intake analysis of the participants indicated that vegetarians have a higher intake of healthy and unhealthy plant-based foods and a lower intake of animal-based foods than non-vegetarians. Consumption of dairy products was lower among female vegetarians than among female non-vegetarians. Notably, consumption of meat was also low among non-vegetarians.

Risk of insomnia

A total of 464 incident cases of insomnia were identified in the study population during the study follow-up period.

After adjusting for potential confounders, a lower risk of insomnia was observed among vegetarians compared to that among non-vegetarians. In particular, a significantly lower risk of insomnia was seen among male participants with the highest hPDI scores. However, no such association was observed among female participants.

Furthermore, a significant association was observed between the consumption of healthful plant-based foods and lower risk of insomnia. In contrast, consumption of animal-based foods was found to increase the risk of insomnia significantly. These associations were observed only among male participants. Among female participants, consumption of healthful and unhealthful plant-based foods was found to reduce the risk of insomnia marginally.

Study significance

The study finds that people consuming plant-based foods have a lower risk of insomnia. The study findings suggest that plant-based diets may improve sleep quality and reduce insomnia risk.

As discussed by the scientists in the paper, a vegetarian diet can help improve sleep quality in many ways. Such diets contain high amounts of fruits, vegetables, legumes, and nuts, which are rich sources of tryptophan and melatonin. Tryptophan is a precursor of melatonin and serotonin, which play vital roles in regulating the sleep cycle. Moreover, evidence indicates that vegetarian diets are effective in reducing inflammation and improving gut microbial composition, which collectively can have a beneficial impact on sleep quality.