The dietary intake, serum levels, and urinary excretion of magnesium, zinc, and copper were studied in 78 women involved in different sports (karate, handball, basketball, and running) and in 65 sedentary women. Seven-day, weighed-food dietary reports revealed that no group of female athletes reached the minimal intake recommended for magnesium (280 mg/day) and zinc (12 mg/day), although their values were superior to those offne control group. The estimated safe and adequate minimal intake of copper (1.5 mg/day) was amply surpassed by the basketball players and runners but was not reached by the handball players. Serum levels and urinary excretion of magnesium, zinc, and copper did not seem related either to their intake or to the type of physical activity performed. The influence of other factors such as nutritional status, bioavailability, intestinal absorption mechanisms, and muscle-level modifications might explain the differences between the different groups of female athletes.
Ramón J. Nuviala, María G. Lapieza and Enrique Bernal
Ioanna Athanasiadou, Sven Christian Voss, Wesal El Saftawy, Hind Al-Jaber, Najib Dbes, Sameera Al-Yazedi, Waseem Samsam, Vidya Mohamed-Ali, Mohammed Alsayrafi, Georgia Valsami and Costas Georgakopoulos
Low urinary luteinizing hormone (LH) values have been discussed as a marker to detect steroid abuse. However, suppressed LH concentrations related to highly diluted urine samples could be a misleading indication of anabolic steroid abuse. One aim of the present study was to examine the effect of hyperhydration on the interpretation of LH findings during doping control analysis and to investigate different possibilities to correct volume-related changes in urinary LH concentrations. Seven healthy, physically active, nonsmoking White males were examined for a 72-hr period, using water and a commercial sports drink as hyperhydration agents (20 ml/kg body weight). Urine samples were collected and analyzed according to the World Anti-Doping Agency’s technical documents. Baseline urinary LH concentrations, expressed as the mean ± SD for each individual, were within the acceptable physiological range (7.11 ± 5.42 IU/L). A comparison of the measured LH values for both hyperhydration phases (Phase A: 4.24 ± 5.60 IU/L and Phase B: 4.74 ± 4.72 IU/L) with the baseline (“normal”) values showed significant differences (Phase A: p < .001 and Phase B: p < .001), suggesting the clear effect of urine dilution due to hyperhydration. However, an adjustment of urinary LH concentrations by specific gravity based on a reference value of 1.020 seems to adequately correct the hyperhydration-induced decrease on the LH levels.
Rebekah D. Alcock, Gregory C. Shaw, Nicolin Tee, Marijke Welvaert and Louise M. Burke
) did not elevate the Hyp excretion at any time point compared with the BL values ( p > .05). There was no difference in the urinary Hyp excretion among the participants for any of the BL measures ( p > .05). Figure 1 —Urinary excretion of hydroxyproline (normalized to creatinine) over 0–6, 6–12, and
Wayne W. Campbell, Lyndon J.O. Joseph, Richard E. Ostlund Jr., Richard A. Anderson, Peter A. Farrell and William J. Evans
This study assessed the effects of resistive training (RT) with or without chromium picolinate (Cr-pic) supplementation on the 24-h urinary excretions of myo-inositol, D-chiro-inositol, and pinitol, as well as clinical indices of kidney and liver functions. Thirty-two nondiabetic subjects, age 62 ± 4 y, performed RT twice weekly for 12 wk and consumed either 924 μg Cr/d as Cr-pic (n = 17) or a placebo (n = 15). Whole-body strength increased in all subjects by 20% and urinary chromium excretion increased 47-fold in the Cr-pic group. Urinary myo-inositol, D-chiro-inositol, and pinitol were not changed with RT or influenced by Cr-pic. Serum indices of kidney and liver functions were within clinically normal ranges at baseline and the end of the study. These results suggest that RT did not influence the urinary excretions of inositols. High dose Cr-pic did not influence the urinary excretion of inositols and the selected indices of kidney and liver functions in conjunction with RT
Rachel D. Smetanka, C. Patrick Lambert, Robert Murray, Dennis Eddy, Mary Horn and Carl V. Gisolfi
Abdominal cramping, nausea, diarrhea, and GI bleeding are often reported in long-distance runners. This study set out to determine the effects of prolonged (2-4 hrs) exercise and NSAID ingestion on gastric and intestinal permeability during the first 5 hrs following the 1996 Chicago Marathon. Thirty-four healthy volunteers (20 M, 14 F; ages 30-50) completed the race and ingested the test solution (5 g sucrose, 5 g lactulose, 2 g rhamnose, in 40 ml water) within 10-15 min. The urinary excretion ratio of lactulose/rhamnose was used to assess small intestine permeability; sucrose excretion was used to evaluate gastric impairment. There were no significant differences for mean training mileage, postrace rectal temperature, and percent dehydration between runners who ingested NSAIDs and those who did not. In all, 75% of subjects reported aspirin or ibuprofen ingestion before or during the race. Runners who ingested ibuprofen had significant elevations in urinary lactulose excretion and lactulose/rhamnose ratio, whereas those who ingested aspirin or who did not ingest either NSAID had no significant differences in urinary excretion of lactulose, rhamnose, sucrose, or lactulose/rhamnose ratio compared to resting controls. Thirteen of the 26 NSAID users and 4 of the 8 non-users reported GI symptoms. It is concluded that (a) ibuprofen but not aspirin ingestion during prolonged exercise may increase gastrointestinal permeability and lead to GI symptoms, and (b) prolonged exercise alone can produce GI symptoms.
James A. Lang, Carl V. Gisolfi and G. Patrick Lambert
The purpose of this study was to determine the effects of exercise intensity on active and passive intestinal glucose absorption. Eight trained runners (age = 23 ± 2 y; VO2max = 62.1 ± 5.8 mL · kg−1 · min−1) performed a 1 h resting experiment and three 1 h treadmill experiments at 30, 50, or 70% VO2max in a thermoneutral environment. Immediately prior to each experiment, euhydrated subjects ingested a solution containing two non-metabolizable glucose analogs, 3-O-methyl-D-glucose (3MG; actively absorbed; 5 g) and D-xylose (passively absorbed; 5 g). During the following 5 h, all urine was collected and the amount of 3MG and D-xylose in the urine was determined. Using repeated measures ANOVA, a significant (P < 0.05) reduction in urinary excretion of each carbohydrate was observed at 70% VO2max compared to the other intensities suggesting that both active and passive intestinal absorption of glucose may be reduced during prolonged running at this intensity.
Shawn M. Talbott and Sue A. Shapses
The purpose of this study was to investigate the influence of an acute 24-hr fast versus usual 24-hr dietary intake on markers of bone turnover in collegiate lightweight male rowers. Bone turnover was measured by serum osteocalcin (OC) and urinary excretion of pyridinium cross-links (pyridinoline [PYD] and deoxypyridinoline [DPD]). Fasting subjects (F) (n = 14) reduced body weight by 1.7 ± 0.5 kg but there was no significant change among nonfasting subjects (NF) (n = 13). Following 24 hr of fasting, PYD and DPD were lower in F (14.1 ± 2.2 and 5.2 ± 0.7 nmol/mmol creatinine, respectively) compared to NF (16.4 ± 3.6 and 6.0 ± 0.8 nmol/mmol creatinine) (p < .05). Fasting also reduced OC levels (4.8 ± 0.4 ng/ml) compared to NF (6.1 ± 0.9 ng/ml) (p < .01). Stepwise regression analysis of NF dietary intake indicated that energy intake explained a greater portion of the variation in bone turnover for PYD (34%), DPD (36%), and osteocalcin (46%) compared to other nutrients (p < .05). These results indicate that bone turnover is reduced by 24 hr of fasting and suggest a role for dietary energy intake in regulating bone turnover.
Paola Rodriguez-Giustiniani and Stuart D.R. Galloway
ingested beverage is low (<23 mmol/L), a large urinary excretion is stimulated if a large volume of fluid is consumed. However, with the ingestion of a large volume of a high sodium beverage (61 mmol/L), a larger proportion of fluid is retained, resulting in a better net fluid balance ( Shirreffs et
D. Enette Larson-Meyer, Kathleen Woolf and Louise Burke
, laxative abuse. Increased urinary excretion of calcium, magnesium and potassium, bone pain, muscle weakness, impaired growth, low oxygen delivery. d Excess: impaired calcium regulation Serum phosphorus has low sensitivity and specificity. Potassium Most vegetables and fruits Common measure: potassium in