Moderate Increase in Protein Intake Promotes a Small Additional Improvement in Functional Capacity, But Not in Muscle Strength and Lean Mass Quality, in Postmenopausal Women Following Resistance Exercise: A Randomized Clinical Trial

Abstract

The aim of this study was to evaluate the effect of a moderate increase in protein intake on muscle strength, functional capacity and lean mass quality improvements in postmenopausal women following resistance exercise. Forty-seven postmenopausal women were randomized in two groups: Normal protein (NP, n = 25), who received a dietary plan containing ~0.8 g protein·kg−1·d−1 (recommended dietary allowance—RDA recommendations); and higher protein (HP, n = 22), which a moderate increase in protein intake was recommended (~1.2 g protein·kg−1·d−1). Resistance training was performed for 10 weeks, three times/week. Muscle strength (handgrip strength and one repetition maximum test—1-RM), functional capacity and lean mass (LM) quality (muscle strength to lean mass ratio) were evaluated. Dietary intake was assessed by nine 24 h food recalls. After intervention, both groups increased similarly the leg extension 1-RM and handgrip strength. Regarding functional capacity tests, both groups increased the balance test score (SPPB) and 10 m walk test speed, with no differences between the groups. In addition, an increase in speed to perform the 6 min and 400 m walk tests was observed over the time, with an additional improvement in the HP group (time × group interaction; p = 0.007 and p = 0.004, respectively). About LM quality, leg extension 1-RM/leg LM improved over the time in both groups (p = 0.050), with no time × group interaction. All these significant changes had a low effect size. In conclusion, a moderate increase in protein intake promoted a small additional improvement in functional capacity, but it did not induce a greater increase in strength and LM quality after 10 weeks of resistance exercise in postmenopausal women. This trial was registered at ClinicalTrials.gov as NCT03024125.

Systematic review and meta‐analysis of protein intake to support muscle mass and function in healthy adults

“…Sixty‐six out of 74 studies were included in the lean body mass change analysis, utilizing 2665 subjects 33–99 . Six studies presented intervention groups not using RE training 41,46,94,97–99 ; of these, four studies tested protein ingestion exclusively, 41,97–99 and two studies tested protein ingestion in groups without and with resistance exercise 46,94 .…”

“…Six studies presented intervention groups not using RE training 41,46,94,97–99 ; of these, four studies tested protein ingestion exclusively, 41,97–99 and two studies tested protein ingestion in groups without and with resistance exercise 46,94 . Changes in strength data resulting from the additional protein intervention were extracted from 50 studies testing 2283 subjects for lower‐body strength 33,36–39,43,44,47–49,52–58,61–65,67–70,72,74–78,82,84,86,88–92,94,96,100–104 and only three studies with intervention groups without RE 41,99,105 . Thirty‐four studies tested bench‐press strength 33,36–38,43,47–49,53–55,62–65,67,68,70,72,74,75,77,78,82,84,86–88,90,91,93,95,96,99 with 1049 subjects.…”

“…Changes in strength data resulting from the additional protein intervention were extracted from 50 studies testing 2283 subjects for lower‐body strength 33,36–39,43,44,47–49,52–58,61–65,67–70,72,74–78,82,84,86,88–92,94,96,100–104 and only three studies with intervention groups without RE 41,99,105 . Thirty‐four studies tested bench‐press strength 33,36–38,43,47–49,53–55,62–65,67,68,70,72,74,75,77,78,82,84,86–88,90,91,93,95,96,99 with 1049 subjects. The duration of the studies was, on average, 12 weeks for both bench‐press and lower body strength.…”

“…Sixty‐six out of 74 studies were included in the lean body mass change analysis, utilizing 2665 subjects. 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 ,…”

Nutrient-dense protein as a primary dietary strategy in healthy ageing: please sir, may we have more?

“…1⋅6 g/kg/d) with concomitant RE. In the second trial, the authors reported that higher protein intake improved functional capacity, as measured by the participants' performance on the Short Physical Performance Battery and various walking tests, but did not improve strength or lean mass (108) . Despite being somewhat inconsistent, these findings still show that consuming more protein and completing RE can yield beneficial results.…”