Exploring Oral Function, Protein Intake, and Risk of Sarcopenia: A Scoping Review

Abstract

Introduction: Sarcopenia is loss of both muscle mass and function with age and is associated with inadequate protein intake. However, evidence to suggest an association with oral health is less clear. Objective: To scope peer-reviewed published evidence (2000–2022) pertaining to oral function in relation to sarcopenia and/or protein intake in older people. Methods: CINAHL, Embase, PubMed, and Scopus were searched. Included were peer-reviewed studies measuring oral function (e.g., tooth loss, salivary flow masticatory function, strength of muscles of mastication, and tongue pressure) and a measure of protein intake and/or a measure of sarcopenia (appendicular muscle mass and function). Full article screening was conducted by 1 reviewer with a random 10% screened in duplicate by a second reviewer. Relevant content pertaining to study type, country of origin, measures of exposure, and outcomes and key findings was mapped and the balance of data showing a positive versus null association of oral health with outcomes charted. Results: Of 376 studies identified, 126 were screened in full, yielding 32 included texts, of which 29 were original articles. Seven reported intake of protein and 22 reported measures of sarcopenia. Nine distinct oral health exposures were identified, with ≤4 studies relating to any one of these measures. Most data were cross-sectional in nature (27 studies) and from Japan (20 studies). The balance of data showed associations between tooth loss and measures of sarcopenia and protein intake. However, the balance of data pertaining to any association between chewing function, tongue pressure, or indices of oral hypofunction and sarcopenia was mixed. Conclusion: A broad range of oral health measures have been studied in relation to sarcopenia. The balance of data suggests that tooth loss is associated with risk, but data pertaining to the oral musculature and indices of oral hypofunction are mixed. Knowledge Transfer Statement: The findings of this research will increase awareness among clinicians of the amount and nature of evidence pertaining to the relationship between oral health and risk of compromised muscle mass and function, including data showing that loss of teeth is associated with increased risk of sarcopenia in older people. The findings highlight to researchers the gaps in the evidence and where further research and clarification of the relationship between oral health and risk of sarcopenia is warranted.