Background: A higher protein intake is suggested to preserve muscle mass during aging and may therefore reduce the risk of sarcopenia.Objectives: We explored whether the amount and type (animal or vegetable) of protein intake were associated with 5-y change in mid-thigh muscle cross-sectional area (CSA) in older adults (n = 1561).Methods: Protein intake was assessed at year 2 by a Block foodfrequency questionnaire in participants (aged 70–79 y) of the Health, Aging, and Body Composition (Health ABC) Study, a prospective cohort study. At year 1 and year 6 mid-thigh muscle CSA in square centimeters was measured by computed tomography. Multiple linearregression analysis was used to examine the association between energy-adjusted protein residuals in grams per day (total, animal, and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity, and 5-y change in fat mass.Results: Mean (95% CI) protein intake was 0.90 (0.88, 0.92) g ·kg–1 · d–1 and mean (95% CI) 5-y change in muscle CSA was −9.8 (−10.6, −8.9) cm2. No association was observed between energyadjusted total (β = −0.00; 95% CI: −0.06, 0.06 cm2; P = 0.982), animal (β = −0.00; 95% CI: −0.06, 0.05 cm2; P = 0.923), or plant(β = +0.07; 95% CI: −0.06, 0.21 cm2; P = 0.276) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle CSA and potential confounders.Conclusions: This study suggests that a higher total, animal, or vegetable protein intake is not associated with 5-y change in midthigh muscle CSA in older adults. This conclusion contradicts some, but not all, previous research. This trial was registered at www.trialregister.nl as NTR6930.
Rationale: A higher protein intake is suggested to preserve muscle mass during aging, and may therefore reduce the risk for sarcopenia. We explored whether the amount, type (animal/vegetable) and essential amino acid (EAA) composition of protein intake were associated with 5-year change in mid-thigh muscle cross-sectional area (CSA) in older adults.Methods: Protein intake was assessed at year 2 by a Block food frequency questionnaire in 2,597 participants of the Health ABC study, aged 70–79 y. At year 1 and year 6 mid-thigh muscle CSA (cm2) was measured by computed tomography. Multiple linear regression analysis was used to examine the association between energy adjusted protein residuals (total, animal and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity and 5-year change in fat mass. EAAintake was expressed as percentage of total protein intake.Results: Mean protein intake was 0.90 (SD 0.36) g/kg/d and mean 5-year change in muscle CSA was −9.8 (17.0) cm2 (n = 1,561). No association was observed between energy adjusted total (β = −0.00 cm2 ; SE = 0.03; P = 0.98), animal (β = −0.00 cm2; SE = 0.03; P = 0.92), and plant (β = +0.07 cm2; SE = 0.07; P = 0.291) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle area and potential confounders. No associations were observed for the EAAs.Conclusion: A higher total, animal or vegetable protein intake was not associated with 5 year change in mid-thigh cross sectional area in older adults. This conclusion contradicts some, but not all previous research, therefore optimal protein intake for older adults is currently not known.
Background & aims: Optimal nutritional support during the acute phase of critical illness remains controversial. We hypothesized that patients with low skeletal muscle area and -density may specifically benefit from early high protein intake. Aim of the present study was to determine the association between early protein intake (day 2–4) and mortality in critically ill intensive care unit (ICU) patients with normal skeletal muscle area, low skeletal muscle area, or combined low skeletal muscle area and -density. Methods: Retrospective database study in mechanically ventilated, adult critically ill patients with an abdominal CT-scan suitable for skeletal muscle assessment around ICU admission, admitted from January 2004 to January 2016 (n = 739). Patients received protocolized nutrition with protein target 1.2–1.5 g/kg/day. Skeletal muscle area and -density were assessed on abdominal CT-scans at the 3rd lumbar vertebra level using previously defined cut-offs. Results: Of 739 included patients (mean age 58 years, 483 male (65%), APACHE II score 23), 294 (40%) were admitted with normal skeletal muscle area and 445 (60%) with low skeletal muscle area. Two hundred (45% of the low skeletal muscle area group) had combined low skeletal muscle area and -density. In the normal skeletal muscle area group, no significant associations were found. In the low skeletal muscle area group, higher early protein intake was associated with lower 60-day mortality (adjusted hazard ratio (HR) per 0.1 g/kg/day 0.82, 95%CI 0.73–0.94) and lower 6-month mortality (HR 0.88, 95%CI 0.79–0.98). Similar associations were found in the combined low skeletal muscle area and -density subgroup (HR 0.76, 95%CI 0.64–0.90 for 60-day mortality and HR 0.80, 95%CI 0.68–0.93 for 6-month mortality). Conclusions: Early high protein intake is associated with lower mortality in critically ill patients with low skeletal muscle area and -density, but not in patients with normal skeletal muscle area on admission. These findings may be a further step to personalized nutrition, although randomized studies are needed to assess causality.
