Information on dietary composition is vitally important for elite athletes to optimise their performance and recovery, which requires valid tools. The aim of the present study was to investigate the validity of assessing protein intake using three web-based 24-h recalls and questionnaires, by comparing these with three urinary N excretions on the same day. A total of forty-seven Dutch elite top athletes, both disabled and non-disabled, aged between 18 and 35 years, with a BMI of 17·5-31 kg/m 2 , exercising >12 h/week were recruited. Estimated mean dietary protein intake was 109·6 (SD 33·0) g/d by recalls and questionnaires v. 141·3 (SD 38·2) g/d based on N excretions in urine; the difference was 25·5 (SD 21·3) % between the methods (P < 0·05). We found a reasonably good association between methods for protein intake of 0·65 (95 % CI 0·45, 0·79). On an individual level, under-reporting was larger with higher protein intakes than with lower intakes. No significant differences were found in reporting absolute differences between subcategories (sex, under-reporting, BMI, collection of recalls within a certain amount of time and using protein supplements or not). In conclusion, combined, multiple, 24-h recalls and questionnaires underestimated protein intake in these young elite athletes more than that reported for non-athlete populations. The method proved to be suitable for ranking athletes according to their protein intake as needed in epidemiological studies. On an individual level, the magnitude of underestimation was about equal for all athletes except for those with very high protein intakes.

PurposeThe effects of moderate beer consumption after physical activity on rehydration and fluid balance are not completely clear. Therefore, in this study, we investigated the effect of beer consumption, with varying alcohol content, on fluid balance after exercise-induced dehydration.MethodsEleven healthy males were included in this cross over study (age 24.5 ± 4.7 years, body weight 75.4 ± 3.3 kg, VO2max 58.3 ± 6.4 mL kg min−1). Subjects exercised on a cycle ergometer for 45 min at 60% of their maximal power output (Wmax) until mild dehydration (1% body mass loss). Thereafter, in random order, one of five experimental beverages was consumed, in an amount equal to 100% of their sweat loss: non-alcoholic beer (0.0%), low-alcohol beer (2.0%), full-strength beer (5.0%), an isotonic sports drink, and water. Fluid balance was assessed up till 5 h after rehydration.ResultsAfter 1 h, urine production was significantly higher for 5% beer compared to the isotonic sports drink (299 ± 143 vs. 105 ± 67 mL; p < 0.01). At the end of the 5-h observation period, net fluid balance (NFB) was negative for all conditions (p = 0.681), with the poorest fluid retention percentage for 5% beer (21% fluid retention) and the best percentage for the isotonic sports drink (42%). Non-alcoholic beer, low-alcoholic beer, and water resulted in fluid retention of 36, 36, and 34%, respectively (p = 0.460).ConclusionThere was no difference in NFB between the different beverages. Only a short-lived difference between full-strength beer and the isotonic sports drink in urine output and NFB was observed after mild exercise-induced dehydration. Fluid replacement – either in the form of non-alcoholic beer, low-alcoholic beer, full-strength beer, water, or an isotonic sports drink of 100% of body mass loss was not sufficient to achieve full rehydration. The combination of a moderate amount of beer, with varying alcohol content, enough water or electrolyte- and carbohydrate beverages, and salty foods might improve rehydration, but more research is needed.