Protein intake by master swimmers: Implications for practice in Sports Nutrition-A cross-sectional study

Background: Proteins are essential for the maintenance, repair, and growth of muscle mass. This is particularly important for master athletes because aging has been associated with loss of muscle mass, function, and strength. Moreover, the timing of intake has been shown important for the best protein utilization. Aim: To analyze timing, quantity, and source of dietary protein in competitive master athletes according to current recommendations. Methods: Twenty-one male master swimmers (47.9 ± 10.0 years; 79.2 ± 6.5 kg; 179.1 ± 5.5 cm; 23.5 ± 4.9% body fat; 73.3 ± 4.2% lean mass) participated in this cross-sectional study. Protein intake was analyzed based on 7-day food records, regarding quantity, timing, and sources of intake. Protein intake was evaluated according to current international sports nutrition guidelines, including the International Society of Sports Nutrition Position Stand. Body fat (%) and lean mass (%) were evaluated using dual-energy X-ray absorptiometry. Results: Participants' mean protein intakes were 1.9 ± 0.5 g/kg/day, 0.6 ± 0.2 g/kg/meal post-training, and 33.5 ± 23.9 g during the pre-sleep period. Daily intake was within the recommended values of 1.4 and 2.0 g/kg/day (p = 0.01 and 0.147, respectively). Mean pre-sleep intake was within the recommendation values of 30-40 g (p = 0.28 and 0.147, respectively). Most of the daily protein intake was consumed at lunch (66.7 ± 6.9 g) and dinner (48.0 ± 4.5 g). Regarding protein sources, intakes from animal, vegetal, and supplements were, respectively, 65.7%, 29.2%, and 5.1%. Conclusion: Master swimmers presented a total protein intake within the recommendations for a daily basis, but the majority of intake was at lunch and dinner. Protein intake could be better distributed throughout the day to optimize protein synthesis. Guidance on daily protein intake distribution should be reinforced in clinical practice.