e., creatinine and blood urea nitrogen). Rats in the high dose condition consuming 6 human equivalent doses per day (would be equivalent to an additional 120 g of protein in humans) increased daily protein intakes up to 21.7 g/kg/day. Additionally, 30-days of creatine feeding present
within the WPH-based supplement did not adversely affect the examined health markers; for the high dose condition this would be equivalent to a human consuming 15 g/d of creatine. Therefore, our 30-day study is in agreement with other literature which continues to refute speculation that whey protein [9, 10] and/or creatine supplementation [29] negatively impacts kidney function and/or elicits kidney damage in animals that do not possess pre-existing kidney issues. Interestingly, animals that were
gavage-fed three and six human equivalent doses per day of the WPH-based supplement for 30 days consumed less #SN-38 concentration randurls[1|1|,|CHEM1|]# total kilocalories per day relative to animals that consumed one human-equivalent dose and water over this time frame. Multiple studies have established that whey protein may exert satiating effects and reduce adiposity in rats [30, 31]. In explaining this effect, authors from the later study propose that whey-derived proteins do elicit a satiating effect through the enhanced secretion of gut neuropeptides including cholecystokinin (CCK) or glucagon-like peptide-1 (GLP-1). Thus, this effect might have been observed in our study although examining circulating CCK and GLP-1 was beyond the scope of our investigation. With regard to body composition Y-27632 chemical structure alterations, however, the feeding intervention
in our study did not confer changes in body fat in the protein supplemented conditions. Likewise, the feeding intervention did not increase DXA lean body mass which has been demonstrated in the aforementioned rodent study that chronically fed rats whey protein over a 25-day period [31]. However, that Pichon et al. [31] used dissection methods to assess body composition whereas our DEXA method may introduce a larger degree of error which could have obscured our findings. Furthermore, we cannot rule out the hypothesis that consuming higher protein diets over longer periods (i.e., years to decades in humans) reduces adiposity and enhances and/or maintains muscle mass during maturation Aspartate and subsequent aging in humans, respectively. It is also noteworthy mentioning that there are limitations to the current study. First, rodents were examined instead of humans with regards to studying leucine, insulin, and toxicological responses to these whey protein sources. It should be noted, however, that rats and humans seem to respond similarly to whey protein as it has been shown to increase circulating leucine and markers of muscle protein synthesis following exercise in both species [3, 32]. Thus, we hypothesize that human responses will likely be similar when examining the physiological effects of WPH versus WPI supplements.