ISSN exercise & sport nutrition review: research & recommendations

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients

Hyperphagia as a mediator of renal disease initiation in obese Zucker rats

Objective: We sought to determine whether prevention of overeating would block the very earliest manifestations of renal injury in young obese Zucker rats (OZRs). Research Methods and Procedures: Three groups of rats were studied, obese (fa/fa) Zucker rats and lean (Fa/Fa). Zucker controls were allowed to feed ad libitum, whereas a group of obese (fa/fa) Zucker rats was pair-fed to the lean group. Urine albumin and serum lipids were studied weekly from 6 to 10 weeks of age. Renal pathology and renal glomerular gene expression were examined when the rats were killed at 10 weeks of age. Results: Obese rats fed ad libitum developed significant albuminuria by 6 weeks of age, increasing at each subsequent time-point. This increase was completely blocked by pair-feeding. Serum triglycerides were significantly increased in obese rats fed ad libitum vs. the other groups. Urine albumin correlated significantly with both body weight and serum triglyceride level. Renal histopathology was normal in all groups. Analysis of gene expression of glomerular proteins by reverse transcriptase-polymerase chain reaction revealed that pair-feeding attenuated the increased expression of glomerular desmin, fibronectin, and the 92-kDa collagenase that was seen in obese animals fed ad libitum. Discussion: Prevention of overeating in young OZR normalizes albuminuria and attenuates the pathogenic alterations in glomerular gene expression seen at the initiation of renal disease in obese animals allowed to feed ad libitum. This model may be relevant for studying the early endorgan effects of obesity

Hyperphagia as a mediator of renal disease initiation in obese Zucker rats

Objective: We sought to determine whether prevention of overeating would block the very earliest manifestations of renal injury in young obese Zucker rats (OZRs). Research Methods and Procedures: Three groups of rats were studied, obese (fa/fa) Zucker rats and lean (Fa/Fa). Zucker controls were allowed to feed ad libitum, whereas a group of obese (fa/fa) Zucker rats was pair-fed to the lean group. Urine albumin and serum lipids were studied weekly from 6 to 10 weeks of age. Renal pathology and renal glomerular gene expression were examined when the rats were killed at 10 weeks of age. Results: Obese rats fed ad libitum developed significant albuminuria by 6 weeks of age, increasing at each subsequent time-point. This increase was completely blocked by pair-feeding. Serum triglycerides were significantly increased in obese rats fed ad libitum vs. the other groups. Urine albumin correlated significantly with both body weight and serum triglyceride level. Renal histopathology was normal in all groups. Analysis of gene expression of glomerular proteins by reverse transcriptase-polymerase chain reaction revealed that pair-feeding attenuated the increased expression of glomerular desmin, fibronectin, and the 92-kDa collagenase that was seen in obese animals fed ad libitum. Discussion: Prevention of overeating in young OZR normalizes albuminuria and attenuates the pathogenic alterations in glomerular gene expression seen at the initiation of renal disease in obese animals allowed to feed ad libitum. This model may be relevant for studying the early endorgan effects of obesity

Estrogen accelerates the development of renal disease in female obese Zucker rats

Estrogen accelerates the development of renal disease in female obese Zucker rats. Renal failure is the primary cause of death in obese Zucker rats (OZR). We previously found that renal injury occurred earlier and with greater severity in female OZR; also, prevention of hyperphagia decreased renal damage in females more than males. To examine the relationship between estrogen (E), hyperphagia, hyperlipidemia, and renal injury in female OZR, we studied four groups from 5 to 10 or 21 weeks of age: Sham-operated (Sham), ovariectomized (Ovx), Ovx with estrogen treatment (Ovx+E), and, since Ovx increases food intake, Ovx pair-fed to sham (Ovx-PF). By only six weeks of age, albumin excretion (UAE) increased significantly in Ovx+E (9.9 ± 4.1 mg/day). Ovx+E also ate least and gained the least weight, but had the highest plasma lipid levels. In contrast, UAE in Ovx did not increase by 10 weeks of age, despite a significantly greater food consumption. The hyperlipidemia of Ovx+E was due primarily to triglycerides. Both plasma triglycerides and renal injury, judged from either histology or UAE, were greatest in the Ovx+E group. Fasting plasma glucose was lower and insulin was higher in Ovx+E compared to Ovx rats at 15 weeks of age. Estrogen may promote renal injury in female OZR by increasing the plasma concentration of triglyceride-rich lipoproteins