High-Protein Diet Associated with Resistance Training Improves Performance and Decreases Adipose Index in Rats.

The study tested the hypothesis that a high protein diet based on isolated whey protein (IWP) associated with strength training improves performance and reduces body fat without promoting health damage. Male Wistar rats, 45 days old, were divided into four groups (n = 8/group): normoprotein sedentary (IWP 14%; NS); hyperprotein sedentary (IWP 35%; HS); normoprotein trained (IWP 14%; NT) and hyperprotein trained (IWP 35%; HT). All groups performed the maximum load test at the beginning and after the vertical ladder training protocol for 6 weeks (3x/week). The performance improved in HT when compared to other groups. There was no difference in the plasma levels of testosterone, IGF-1 and the hematological parameters remained normal. The relative weights of the kidneys were higher in the groups fed with high protein; the liver was higher in HT compared to NS and NT, and the heart was higher in HS compared to NS and NT. Concerning relative muscle weight, quadriceps, and gastrocnemius, HT showed higher value compared to NT. Diet containing 35% isolate whey protein associated with resistance training improved performance as well as increased muscles and organs weight of the animals, without damaging the tissues related to protein metabolism (confirmed by unchanged hematological parameters), which may minimize the risk of developing cardiometabolic disorders.

Effects of high-protein diet containing isolated whey protein in rats submitted to resistance training of aquatic jumps.

OBJECTIVES: Isolated whey protein (IWP) can decrease body fat compared with other protein sources. The present study verified the effects of high protein diet (HD) containing IWP on several parameters of rats subjected to resistance training (RT). METHODS: Thirty-two male Wistar rats (60 days of age) were separated into four groups (n = 8/group): sedentary normoproteic (IWP 14%; SN); sedentary hyperproteic (IWP 35%; SH); trained normoproteic (IWP 14%; TN), and trained hyperproteic (WPI 35%; TH). RESULTS: Relative tissue/organ weight (g): perirenal and retroperitoneal adipose tissues were lower in SH and TH compared with SN (no difference to TN); omental and subcutaneous adipose tissues were higher in SN compared with SH. Epididymal adipose tissue was higher in SN compared with other groups. Heart weight was higher in TH compared with TN and SN, but not SH; kidney and liver higher in TH and SH compared with SN and TN; gastrocnemius lower in SN compared with other groups; soleus higher in SH in relation to other groups. The triglycerides levels (mg/dL) was reduced in the TH groups compared with SH, TN, and SN. There were no changes both in the concentrations of adiponectin and leptin and in the protein expression of GLUT-4 and p70s6k. CONCLUSION: HD containing WPI improved body composition, increased the weight of the heart, kidneys, liver and gastrocnemius and soleus muscles; however, this diet maintained the normal histomorphology of muscle and liver and, when associated with RT, reduced the serum levels of triglycerides.

Effect of administration of high-protein diet in rats submitted to resistance training.

PURPOSE: Although there is limited evidence regarding the pathophysiological effects of a high-protein diet (HD), it is believed that this type of diet could overload the body and cause damage to the organs directly involved with protein metabolism and excretion. The aim of this study was to verify the effects of HD on biochemical and morphological parameters of rats that completed a resistance training protocol (RT; aquatic jump) for 8 weeks. METHODS: Thirty-two adult male Wistar rats were divided into four groups (n = 8 for each group): sedentary normal protein diet (SN-14%), sedentary high-protein diet (SH-35%), trained normal protein diet (TN-14%), and trained high-protein diet (TH-35%). Biochemical, tissue, and morphological measurements were made. RESULTS: Kidney (1.91 ± 0.34) and liver weights (12.88 ± 1.42) were higher in the SH. Soleus muscle weight was higher in the SH (0.22 ± 0.03) when compared to all groups. Blood glucose (123.2 ± 1.8), triglycerides (128.5 ± 44.0), and HDL cholesterol levels (65.7 ± 20.9) were also higher in the SH compared with the other experimental groups. Exercise reduced urea levels in the trained groups TN and TH (31.0 ± 4.1 and 36.8 ± 6.6), respectively. Creatinine levels were lower in TH and SH groups (0.68 ± 0.12; 0.54 ± 0.19), respectively. HD negatively altered renal morphology in SH, but when associated with RT, the apparent damage was partially reversed. In addition, the aquatic jump protocol reversed the damage to the gastrocnemius muscle caused by the HD. CONCLUSIONS: A high-protein diet promoted negative metabolic and morphological changes, while RT was effective in reversing these deleterious effects.

Heteropterys tomentosa A. Juss: Toxicological and adaptogenic effects in experimental models.

BACKGROUND: The constant pursuit of improved athletic performance characterizes high-performance sport and the use of medicinal plants as dietary supplements is becoming widespread among athletes to enhance long-term endurance performance. AIM: The present study evaluated the toxicity of Heteropterys tomentosa (HEHt) and its acute adaptogenic effects. METHODS: The in vitro safety profile was evaluated on CHO-k1 cells using the alamar Blue assay, at concentrations ranging from 3.125 to 200 µg/mL. In vivo acute oral toxicity was conducted in male and female mice with oral administration of graded doses of HEHt from 400 to 2000 mg/kg. A subchronic oral toxicity study was completed by oral administration of HEHt (50, 200 or 1000 mg/kg) and vehicle for 30 days in male Wistar rats. Clinical observations and toxicological related parameters were determined. Blood was collected for biochemical and hematological analyses, while histological examinations were performed on selected organs. Thereafter, an adaptogenic test consisting of progressive loads until exhaustion was conducted in rats ( n = 5/group) orally pre-treated with the vehicle and HEHt (25, 100 or 400 mg/kg). RESULTS: HEHt exhibited no cytotoxic effects on the CHO-k1 cells and, apparently, no acute toxicity in mice and no subchronic toxicity in rats. An ergogenic effect was observed only at the dose of 25 mg/kg compared with the vehicle in relation to time to exhaustion and exercise load ( p = .011 and .019, respectively). HEHt is safe at up to 400 mg/kg, contains astilbin and taxifolin as the major phytochemical compounds, and exhibited a potential adaptogenic effect. CONCLUSIONS: These results justify its anecdotal usage as a tonic, show that the hydroethanolic maceration of the root does not cause toxicity, and provide scientific evidence of its potential as a source of new adaptogenic substance(s).