Worldwide, supplement use amongst athletes ranges between 40 and 60%(Reference Petroczi and Naughton1). Despite the fact supplement use is commonplace no study has measured the effect of taking supplements on protein and amino acid intake. Additionally the recommended daily intake for protein varies depending on athlete type(Reference Campbell, Kreider and Ziegenfuss2). Requirement for protein has also been suggested to vary according to lean body mass(Reference Sears3). The aim of this study was to examine protein intake of exercising males who do and do not take protein supplements and investigate whether they were achieving their desired intake level according to current recommendations.
Following ethical approval 65 physically active males who did not take protein supplements and 62 males who took supplements were recruited. Subjects completed a 3 day food diary, were asked if they eat a high protein diet and recorded any supplements consumed. Dietary analysis was completed through CompEatTM. Lean body mass was measured by a DEXA scan. Supplemental protein and essential amino acid intake were obtained from the supplement label.
a Protein RDA based on individual physical activity levels(Reference Campbell, Kreider and Ziegenfuss2).
b Protein intake based on lean body mass is recommended at 2.75 g/Kg LBM.
c RDA's for essential amino acids based on Dietary Reference Intakes (DRIs) for Macronutrients and Energy.
Protein intake calculated based on physical activity levels(Reference Campbell, Kreider and Ziegenfuss2)) was 37% and 56% greater than recommended intakes with supplement use. When intake was calculated based on lean body mass, subjects not consuming supplements, taking extra dietary protein only or extra protein supplements only, failed to meet their protein requirements. Subjects relying on diet only for essential amino acids failed to meet their recommended intake for phenylalanine, methionine and lysine with these shortfalls being eliminated through supplement intake.
This work was supported by Strand I funding under the Technological Sector Research grant.