Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group

Abstract

New evidence shows that older adults need more dietary protein than do younger adults to support good health, promote recovery from illness, and maintain functionality. Older people need to make up for age-related changes in protein metabolism, such as high splanchnic extraction and declining anabolic responses to ingested protein. They also need more protein to offset inflammatory and catabolic conditions associated with chronic and acute diseases that occur commonly with aging. With the goal of developing updated, evidence-based recommendations for optimal protein intake by older people, the European Union Geriatric Medicine Society (EUGMS), in cooperation with other scientific organizations, appointed an international study group to review dietary protein needs with aging (PROT-AGE Study Group). To help older people (>65 years) maintain and regain lean body mass and function, the PROT-AGE study group recommends average daily intake at least in the range of 1.0 to 1.2 g protein per kilogram of body weight per day. Both endurance- and resistance-type exercises are recommended at individualized levels that are safe and tolerated, and higher protein intake (ie, ≥ 1.2 g/kg body weight/d) is advised for those who are exercising and otherwise active. Most older adults who have acute or chronic diseases need even more dietary protein (ie, 1.2-1.5 g/kg body weight/d). Older people with severe kidney disease (ie, estimated GFR <30 mL/min/1.73 m(2)), but who are not on dialysis, are an exception to this rule; these individuals may need to limit protein intake. Protein quality, timing of ingestion, and intake of other nutritional supplements may be relevant, but evidence is not yet sufficient to support specific recommendations. Older people are vulnerable to losses in physical function capacity, and such losses predict loss of independence, falls, and even mortality. Thus, future studies aimed at pinpointing optimal protein intake in specific populations of older people need to include measures of physical function.

An increased need for dietary cysteine in support of glutathione synthesis may underlie the increased risk for mortality associated with low protein intake in the elderly

“…In contrast, among subjects over 65 at baseline, such a low protein intake was associated with increased risk for overall and cancer-linked mortality. This latter finding is concordant with considerable evidence that the elderly may have an increased requirement for dietary proteinperhaps even higher than current recommendations (Rafii et al 2014)-and that increased protein intakes in the elderly tend to be associated with improved health outcomes (Bauer et al 2013).…”

“…Other studies have correlated higher protein intakes in the elderly with higher bone mass, or, prospectively, less loss of bone mass and lower fracture risk (Kerstetter et al 2000;Rapuri et al 2003;Hannan et al 2000;Misra et al 2011). There is a growing consensus among gerontologists that protein requirements are higher in elderly people than in younger people (Bauer et al 2013).…”

Mediterranean Diet attenuates risk of frailty and sarcopenia: New insights and future directions

“…Moreover, the need for more dietary protein with ageing is in part due to a compromised ability to efficiently utilize amino acids for MPS, resulting in a blunted muscle protein synthetic response to an anabolic stimuli, a phenomenon termed anabolic resistance [105,106]. As of consequence, evidence based recommendations for protein intake in older adults have recently been published [107,108]. Despite the potential role of dietary protein in relation to muscle preservation and function, an important determinant of MPS is not only an adequate intake of dietary protein but also the signalling of anabolic molecules [109].…”

Anorexia of ageing: a key component in the pathogenesis of both sarcopenia and cachexia

“…For these reasons, we strongly recommend regularly monitoring and treating nutritional abnormalities in older persons 55, 56, 57, 58. When anorexia is associated with weight loss, the appropriate nutritional supplement is a leucine‐enriched essential amino acid mixture 59, 60. Drugs such as dronabinol and megestrol acetate have a small effect in increasing food intake 61, 62.…”