Sleep extension improves diet quality, health
Sleep extension (SE) may be a feasible approach to improving diet quality and overall health, according to a recent trial, which showed that SE interventions decreased the intake of free sugars.
“We conclude that a tailored behavioural SE intervention targeting sleep hygiene is feasible in healthy, free-living young adults, which shows the utility of including sleep hygiene guidelines in public health messages,” said researchers, noting that the trial did not report substantial impacts on disease risks and body indices.
“No effects were observed on indexes of body composition, energy balance, cardiometabolic risk, appetite hormones or heart rate variability as a result of the intervention,” they added.
Researchers randomized 42 normal-weight, healthy, habitual short-sleepers to receive either a personalized SE protocol (n=21) or a control intervention (n=21), which required them to maintain habitual sleep.
Sugar intake was significantly affected by the SE intervention. Those who received the SE protocol reported significantly lower consumption of free sugars compared with controls (mean difference, ‒10.3 g/day; 95 percent CI, ‒20.2 to ‒0.4; p=0.042). [Am J Clin Nutr 2017;doi:10.1093/ajcn/nqx030]
The change in free sugar intake from baseline was also significant only in the SE group (change, ‒9.6 g/day; ‒16.0 to ‒3.1; p=0.002), but not in the control group (change, 0.7 g/d; ‒5.7 to 7.2).
Intake of carbohydrates (mean difference, ‒25.0 g/day; ‒53.4 to 3.4; p=0.083) and fat (mean difference, ‒3.0 percentage of energy; ‒6.4 to 0.3; p=0.074) likewise showed borderline significant reductions in the SE group relative to the control group.
Notably, while protein intake, in terms of percentage of energy, was significantly higher in controls than in SE participants (mean difference, 3.4 percentage of energy; 0.6–6.2; p=0.018), no difference in the grams of protein consumed per day was observed (mean difference, 4.5 g/day; 11.5–20.6; p=0.570).
On the other hand, the SE intervention protocol did not exert significant effects on anthropometric, energy expenditure and physical activity measures, such as body mass index (mean difference, 0.1 kg/m2; ‒0.1 to 0.4), body weight (mean difference, 0.3 kg; ‒0.4 to 1.1), resting metabolic rate (mean difference, 23 kcal; ‒58 to 104) and vigorous physical activity (mean difference, ‒0.3 percent of active time; ‒2.1 to 1.5).
“[T]he change in the percentage of energy from free sugars was not different between groups, suggesting that the reduction in sugary foods was not independent of reported total energy consumed,” said researchers.
While the study has produced new and interesting findings about the importance of sleep hygiene, its quality is limited by its failure to blind participants to the SE intervention, introducing potential confounders and bias.
“The results of this trial need to be confirmed by using methods less prone to bias, necessitating inpatient dietary assessment or biomarker studies,” researchers said, adding that future improvements of the study could also investigate SE on a longitudinal scale.
“Larger and longer-term [randomized controlled trials] are needed to examine the effects of continued adherence to sleep hygiene advice and preservation of sleep quality on energy balance, particularly in ‘at risk’ populations,” they said.