Higher protein intake improves sleep and blood pressure, and influences the relation between changes in blood pressure and sleep during energy restriction in middle‐aged overweight and obese adults

Background Short sleep duration and low sleep quality predict higher blood pressure (BP). BP is also shown to be improved by higher protein intake. However, limited research exists on the effects of dietary protein intake on indices of sleep and whether it influences the relation between BP and sleep. Purpose We assessed the effect of protein intake during dietary energy restriction on indices of sleep and BP in overweight/obese adults (randomized, parallel, and controlled diet design). Method Forty‐four participants (12M:32F, aged 52±1 y, BMI 31.4±0.5 kg/m 2 , Mean±SE) consumed an energy‐balance diet with 0.8 g protein·kg baseline body mass −1 ·d −1 for 3 wk (baseline). They then consumed either a normal protein (NP, control, n=23) or high protein (HP, n=21) (0.8 vs. 1.5 g•kg −1 •d −1 ) energy‐restricted diet (750 kcal/d deficit) for 16 wk. The HP group consumed 0.7 g·kg −1 ·d −1 additional protein using milk protein isolate. At baseline wk 3 and intervention wk 4, 8, 12, and 16, global sleep score (GSS) was assessed using the Pittsburgh Sleep Quality Index questionnaire. GSS ranges from 0–21 arbitrary units (au) with a higher value representing worse GSS during the preceding month. Fasting state reclining systolic (SYS) and diastolic (DIA) BPs were also measured. The main effects of group (protein intake) and time (energy restriction) and group*time interaction on GSS and BP were assessed using repeated measures ANOVA, adjusting for age and gender. The relation between BP and GSS at baseline and during the intervention (wk 4, 8, 12, and 16) and the relation between their changes from baseline to post intervention (wk 16) were assessed using general linear model, adjusting for age and gender. Results At baseline, GSS was not different between NP (5.2±0.5 au) and HP (5.4±0.5 au). Over time, GSS was unchanged for NP and improved for HP (group‐by‐time, p <0.05). Post‐intervention, GSS for NP and HP were 5.9±0.5 and 4.0±0.6 au, respectively ( p <0.01). SYS and DIA BPs were not different between NP (119±2 and 81±2 mmHg, respectively) and HP (121±3 and 84±2 mmHg, respectively) at baseline. SYS BP remained unchanged in NP (2±2 mmHg), but decreased in HP (−4±2 mmHg). DIA BP was reduced over time, with a trend toward a smaller improvement in NP vs. HP (group by time interaction: p =0.09, respectively). At baseline, a relation between BP and GSS was not observed. During the intervention, GSS positively predicted SYS and DIA BPs (β = 1.38 and 1.04, respectively, p <0.05) for NP, but was not related to SYS BP and negatively predicted DIA BP (β = −0.64, p <0.05) for HP. From baseline wk 3 to intervention wk 16, changes in GSS positively predicted changes in SYS and DIA BPs (β = 1.48 and 0.69, respectively, p <0.05) in NP, but negatively predicted SYS and DIA BPs (β=−1.70 and −1.48, respectively, p <0.05) in HP. Collectively, higher/increases in BPs were associated with worse/worsened sleep in NP but not HP. Conclusion Consuming a higher protein diet achieved using milk protein isolate while dieting may improve indices of sleep and blood pressure, and protect against the negative influence of worse sleep on blood pressure in overweight/obese adults. Support or Funding Information National Dairy Council, Purdue Ingestive Behavior Research Center, and NIH UL1TR001108