Plant proteins improve sleep quality, while animal proteins disrupt it
Last reviewed: 07.06.2024
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In a recent study published in European Journal of Clinical Nutrition, researchers report that consuming protein from plant-based sources may improve sleep quality. While increased intake of animal protein worsens sleep quality.
How does diet affect sleep?
Quality sleep at night is essential for a healthy lifestyle. During sleep there are changes in metabolism, blood circulation, hormone production and immune regulation functions, all of which are necessary to maintain homeostasis in the body.
Adults need seven to eight hours of sleep each day to reduce the risk of chronic disease and mortality. However, in recent decades, there has been a significant reduction in sleep duration in society, with many people reporting difficulty falling asleep and staying asleep, as well as waking up several times a night and early in the morning. There has also been an increase in the prevalence of both sleep disorders and disorders that can lead to impaired daytime functioning and an increase in numerous chronic diseases.
A poor quality diet characterized by increased intake of saturated fat, refined carbohydrates, and processed foods may reduce sleep quality and duration. Studies have yielded conflicting results regarding the effect of protein intake on sleep quality, which may be due to the varying ratios of specific amino acids in different protein sources.
Basic information about the study
In the present study, researchers investigated the effects of total protein intake and protein intake from various sources on sleep quality. To do so, data on dietary intake and measures of sleep quality were collected from three ongoing prospective cohort studies among health care workers in the United States, including the Nurses' Health Science Study (NHS), NHS2, and the Health Professionals Follow-up Study (HPFS).
In these cohort studies, participants' food intake was assessed every four years using validated food frequency questionnaires. Sleep quality was assessed using the original or modified version of the Pittsburgh Sleep Quality Index.
Data from a total of 32,212 and 51,126 women from the NHS and NHS2 studies, respectively, and 14,796 men from the HPFS were analyzed to determine the association between protein intake and sleep quality.
Important observations
In all three cohorts, participants with the highest protein intake had higher body mass index (BMI) values and a greater prevalence of previous health conditions than those with lower protein intake. More than 65% of study participants reported seven to eight hours of sleep each night.
Regular use of sleeping pills was noted in 5-6% of study participants. The presence of sleep apnea was more common among participants with the highest protein intake, and the prevalence of this condition was higher in men than in women.
Study participants with better sleep quality were associated with lower BMIs, more physical activity, better diet quality, higher alcohol consumption, and fewer previous illnesses.
The relationship between protein intake and sleep quality
In the present study, no association was found between total protein intake and sleep quality. Although total animal protein intake was not associated with sleep quality, higher vegetable protein intake was associated with better sleep quality.
Among the different sources of animal protein, milk protein intake had multidirectional associations. While no association between milk protein intake and sleep quality was found in the NHS and HPFS cohorts, a positive association was found in the NHS2 cohort.
Among the different meat sources, consumption of processed and unprocessed red meat and poultry was associated with worse sleep quality. This association was not observed for fish consumption.
Conclusions
In the present study, no association was found between total protein intake and sleep quality among men and women; however, a positive association was found between plant protein intake and sleep quality. After adjustment for potential mixed-effects factors, this association was less striking in men and weaker in women.
Plant-based protein sources are often rich in carbohydrates and fiber, both of which improve sleep quality. In comparison, processed red meat and poultry, which are rich in fat, can also lead to worse sleep quality, as observed in this study.