Dietary Intake of Protein and Essential Amino Acids for Sustainable Muscle Development in Elite Male Athletes

Athletes need to develop a relatively high muscle mass and low body adipose tissue for the sake of better athletic performance. A full range of nine essential amino acids and eleven non-essential amino acids have to attend in appropriate amounts for protein biosynthesis. The aim of the observational comparative cross-sectional study was to assess the association between the diet quality profile and training-induced muscle mass estimated by bioelectrical impedance among elite male athletes. The research sample comprised 18.1 ± 3.1 year-old Lithuanian professional male athletes (n = 234). The study participants were enrolled to complete 24-h dietary recalls of three non-consecutive days. The body composition was assessed using the bioelectrical impedance analysis (BIA) method. The present study showed a significant insufficiency of the mean carbohydrate intake of 5.7 g/kg/day in a group of aerobic male athletes. The lower muscle mass of aerobic male athletes was related to the lower-carbohydrate diet (adjusted odd ratio (ORadj) 0.3; 95% confidence interval (CI): 0.1-0.7). The mean protein intake of 1.8 g/kg/day was optimal for anabolism in the samples of both anaerobic and aerobic male athletes. The protein intake in appropriate doses was potentially associated with an increase in muscle mass only in anaerobic male athletes (ORadj 2.2; 95% CI: 1.3-3.7). The positive relationship was revealed between the possible muscle mass gain and the increased intakes of amino acids such as isoleucine and histidine among anaerobic athletes (ORadj 2.9; 95% CI: 1.1-4.7 and ORadj 2.9; 95% CI: 1.0-4.3, respectively). An inverse feasible association was indicated between a higher intake of valine and lower muscle mass quantities among anaerobic male athletes (ORadj 0.1; 95% CI: 0.1-0.5). The recommendations for sports nutritionists should emphasize the necessity of advising professional athletes on dietary strategies on how to manipulate dietary amino acid composition with respect to achieving long-term body composition goals.

Comparison between DOQI and Canadian Guidelines for Peritoneal Dialysis

The recently published Canadian Society of Nephrology (CSN) Guidelines for Peritoneal Dialysis Adequacy differ in a number of ways from the United States National Kidney Foundation Dialysis Outcomes Quality Initiative (DOQI) guidelines on the same topic. The three main differences are ( 1 ) the CSN targets are the same for continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD), whereas the DOQI targets are higher for APD; ( 2 ) the CSN guidelines have a lower creatinine clearance (CCr) target of 50 L/wk for low and low-average transporters compared to 60 L/wk for high and high-average transporters, but no such distinction is made by DOQI; and ( 3 ) the CSN has set lower limit targets as well as preferred targets for Kt/V and CCr.

Other differences are that the CSN recommendations do not give Kt/V the same primacy over CCr that DOQI does. Also, the CSN recommendations give greater emphasis to the risks associated with high transport status.

This review looks at the reasons for these differences and demonstrates that some are due to information that has become available since the publication of the DOQI guidelines. However, it is emphasized that, when recommendations are predominantly opinion- rather than evidence-based, geographic and economic factors may also account for differences.

Impact of C-reactive protein and pulse pressure evaluated at the start of peritoneal dialysis on cardiovascular events in the course of treatment with peritoneal dialysis

BACKGROUND

Despite a reduced number of infectious complications, cardiovascular (CV) mortality remains unchanged in peritoneal dialysis (PD) patients. The aim of this study was to evaluate the effects of high-sensitivity C-reactive protein (hs-CRP) and pulse pressure (PP) at the start of PD on the development of CV events (CVEs) in these patients.

METHODS

The study population was comprised of 291 patients that started PD between January 2003 and June 2008 and were treated for more than 6 months. Baseline clinical, biochemical, and echocardiographic data, indices of dialysis adequacy, and peritoneal transport rate were reviewed retrospectively. The clinical outcome was the occurrence of a CVE.

RESULTS

Mean duration of follow-up was 28 (range 6 - 70) months. A CVE was observed in 33 patients (11.3%). The 1-, 3-, and 5-year cumulative incidences of CVEs were 4.0%, 13.7%, and 27.5%, respectively. Although multiple variables were correlated with the prevalence of a CVE in the univariate analysis, hs-CRP, PP, and comorbidity remained significant after adjustment: hs-CRP: odds ratio (OR) 4.09 (1.53 - 10.95), p = 0.005; PP: OR 2.79 (1.26 - 6.17), p = 0.012. PP and hs-CRP, which were not intercorrelated in our data, combined adversely to increase the incidence of CVEs. The incidence of CVEs increased with the number of risk factors, which included high hs-CRP, high PP, and the presence of comorbidity (no risk factor, 0%; 1 risk factor, 1.5%; 2 risk factors, 30.8%; 3 risk factors, 53.9%).

CONCLUSIONS

Our study suggests that measurements of hs-CRP and PP at the start of PD may be helpful in predicting the development of CVEs in the course of treatment with PD.

Assessment of protein nitrogen appearance in Chinese peritoneal dialysis patients-which method to use?

OBJECTIVE

We compared the Bergstrom's and Randerson's formula for PNA determination, and compared the normalization of PNA by ideal body weight (IBW) and standard body weight (SBW) as estimated by the Watson's formula. METHODS. We studied 208 Chinese PD patients. Two 24-h dialysate and urine collections were performed six months apart. Protein nitrogen appearance was determined by the Randerson's formula (PNA-Rand) and Bergstrom's formula (PNA-Berg), the latter used as the gold standard. PNA-Berg was normalized with IBW and SBW, denoted as NPNA-IBW and NPNA-Watson respectively. The change of PNA over six months, denoted as APNA-Rand and APNA-Berg, were calculated. The results were compared by the Bland and Altman's method.

RESULTS

At zero month, the average PNA-Berg was 61.8 +/- 14.8 g/day, and the average PNA-Rand was 58.1 +/- 14.5 g/day. The value of PNA-Rand was consistently lower than the corresponding PNA-Berg. The bias of PNA-Rand was -3.7g/day. The limits of agreement were -9.2 to +1.8 g/day. When NPNA-Watson was compared to NPNA-IBW, the bias of NPNA-Watson, using NPNA-IBW as gold standard, was 0.01 g/kg/day; the limits of agreement were -0.22 to +0.23 g/kg/day. The difference between NPNA-Watson and NPNA-IBW correlated with the body mass index (r = -0.820, p < 0.001) and body weight (r = -0.834, r < 0.001). After six month, there was a significant reduction in urine protein loss. However, total protein loss was only slightly reduced (7.3 +/- 3.0 to 6.9 +/- 2.8 g/day, p = 0.029). The correlation between APNA-Berg and APNA-Rand remained excellent (r = 0.983, p < 0.001). The bias of APNA-Rand was +0.3 g/day; the limits of agreement were -4.7 to +5.2 g/day.

CONCLUSION

Ideal body weight that is validated for specific ethnic group, rather than the Watson's formula, should be used for normalization of PNA. Although the Randerson's formula under-estimates PNA when compared to the Bergstrom's formula, it is a reliable method for serial PNA monitoring because dialysate protein loss is stable in most patients.