Habitual dietary collagen intake is lower in women and older Irish adults compared to younger men.

Background: Collagen ingestion is purported to benefit connective tissues, such as skin, bone, muscle, tendon, and ligament. However, the quantity of collagen intake in the diet of European adults is unknown.

Objective: To investigate collagen intake in the habitual diets of Irish adults, and whether it differed according to sex and/or age.

Methods: We conducted secondary analysis of the Irish National Adult Nutrition Survey, which assessed typical dietary intake using a four-day food diary in 1,500 adults, aged 18-90 years. We categorized participants into three age groups: young (18-39 years, n=630), middle-aged (40-64 years, n=644), and older (≥65 years, n=226) adults. Collagen composition of each individual food item in the database was determined by applying a percentage collagen value from analytical sources, allowing computation of collagen mean daily intake (MDI), collagen MDI relative to body mass, and collagen/total protein MDI. Differences in intakes between age groups and sexes were evaluated using physical activity level as a covariate.

Results: Collagen MDI for the entire population was 3.2±2.0 g∙day, representing 3.6±1.9% total protein intake. Men had higher absolute and relative collagen MDI than women, regardless of age (4.0±2.1 g∙day vs. 2.3±1.4 g∙day, p<0.001), while older adults had lower absolute collagen MDI than middle-aged adults (2.9±1.8 g∙day vs. 3.3±2.0g∙day, p=0.021).

Conclusions: Collagen intake in the Irish adult population was considered low (relative to total protein intake and to dose-response studies), particularly in women and older individuals. Increasing daily collagen intake may therefore be warranted to optimise the health of collagen-rich tissues.