Association Between Dietary Protein Intake and Sleep Quality in Middle-Aged and Older Adults in Singapore

Abstract

Poor sleep has been associated with the increased risk of developing detrimental health conditions. Diet and certain nutrients, such as dietary protein (PRO) may improve sleep. This cross-sectional study aimed to investigate the relationship between PRO intake, their amino acid components, and sources with sleep quality in middle-aged and older adults residing in Singapore. A dataset of 104 healthy subjects between the age of 50 and 75 years old were used. Collected data included 3-day food record and sleep quality [sleep duration, global sleep score (GSS), sleep latency (SL), and sleep efficiency (SE)]. The collected 3-day food records were extracted for PRO, tryptophan (Trp), and large neutral amino acid (LNAA) intake. PRO intake was further categorized into plant and animal PRO. A multivariate multiple linear regression (MLR) was performed to assess the association between PRO intake and sleep quality. Dietary Trp:LNAA ratio was positively associated with sleep duration (βtotal: 108.234 h; p: 0.005) after multiple covariates adjustment. Similarly, plant Trp (βplant: 2.653 h/g; p: 0.020) and plant Trp:LNAA (βplant: 54.006 h; p: 0.008) was positively associated with sleep duration. No significant associations were observed for both SL and SE. Sleep duration in middle-aged and older Singaporean adults was positively associated with dietary Trp and Trp:LNAA, especially when obtained from plant sources.

The effects of low calorie, high protein diet on body composition, duration and sleep quality on obese adults: A randomized clinical trial

“…16 Sutanto and colleagues showed that dietary tryptophan has a significant positive correlation with sleep duration. 31 However, they reported that that there is no clear correlation between high-protein diets and sleep quality and latency. Halson and colleagues state that increasing carbohydrate intake can decrease sleep latency and increasing protein intake can increase sleep quality.…”

“…A number of studies have shown that high‐protein diets enhance sleep quality indices, 22,29,30 although some studies do not report an explicit relationship between high protein intake and sleep quality 16 . Sutanto and colleagues showed that dietary tryptophan has a significant positive correlation with sleep duration 31 . However, they reported that that there is no clear correlation between high‐protein diets and sleep quality and latency.…”

The interplay between macronutrients and sleep: focus on circadian and homeostatic processes

“…As already discussed, Trp is an essential amino acid that, after passing the brain blood barrier, is converted in serotonin and ultimately to melatonin, which promotes sleep. Sleep duration is positively associated with the dietary Trp: LNAA ratio ( 37 ). The reason for which this ratio among dietary intake of Trp and LNAA is related to sleep duration may be due to the fact that LNAA compete with Trp to bind to a carrier protein to pass the blood–brain barrier ( 157 ), influencing brain Trp bioavailability.…”

“…The authors observed that sleep duration was directly related to the protein intake ( 140 ). A study in 104 healthy adults and older individuals from Singapore investigated the relationship among protein intake and sleep, focusing on tryptophan intake ( 37 ). Sleep duration was positively associated to dietary Trp: LNAA ratio but also to plant Trp and plant Trp: LNAA, and this interestingly suggest that the source of protein may play a role.…”

“…Some hormones may be involved in the association between metabolic disturbances and reduced sleep. The higher levels of cortisol due to the condition of chronic stress related to sleep deprivation may explain this relationship, through the increased levels of insulin resistance and inflammation ( 37 ). Moreover, the appetite regulation hormones are altered, and lead to an increased energy intake.…”