Dietary protein safety and resistance exercise: what do we really know?
Abstract: resistance trainers continue to receive mixed messages about the safety of purposely seeking ample dietary protein in their quest for stimulating protein synthesis, improving performance, or maintaining health. Despite protein`s lay popularity andthe routinely high intakes exhibited by strength athletes, liberal and purposeful protein consumption is often by “experts” university textbooks, instructors, and various forms of literature from personal training groups and athletic organizations continue to use dissuasive language surrounding dietary protein. Due to the widely known health benefits of dietary protein and a growing body ofevidence on its safety profile, this is unfortunate. In response, researchers have critiqued unfounded educational messages. As a recent summarizing example, the international society of sport nutrition (ISSN) position stands: protein and exercise reviewed general literature on renal and bone health. The concluding remarks that “concerns that protein intake within this range” (1.4 - 2.0g/kg body weightper day) is unhealthy are unfounded in healthy, exercising individuals”. “Was based largely upon data from non-athletes due to” “a lack of scientific evidence”. Future studies were deemed necessary. This assessment is not unique in the scientific literature. Investigators continue to cite controversy, debate, and the lack of direct evidence that allows it. This review discusses the few existingsafety studies done specific to resistance trainers. Population-specific, long term data will be necessary for effective education in dietetics textbooks and from sports governing bodies.
Introduction: There appears to be an element of disconnectedness between scientific evidence and health messages offered tostudents and athletes. Statements of concern over the effects of ample dietary protein intakes appear in table 1. Research on healthy populations, however, does not support such concerns. One summary of the literature on this topic, the international society of sports nutrition (ISSN) position stand: protein and exercise (1) reviewed literature on renal and bone health, among other topics. Althoughbalanced in its inclusion of both negative (no evidence of harm) and positive (extrapolated evidence of potential concern) studies, the position stand was largely without mention of athlete-specific data on safety topics. Examples of athlete-specific research, although rare, do exist and are included in this review. Three safety issues are commonly mentioned in popular media and nutrition and dietetictextbooks, while sports governing bodies may focus upon the risk of dietary supplements per se (2.3) one issue is renal “stress” , (2,4) a second issue is calcium loss and bone catabolism (2,5,6) and a third is an assumption that higher protein intakes are higher in saturated fat and lower in fiber (2). Language surrounding these topics can be dissuasive and/or uncertain regarding purposefulconsumption of protein for weight control or athletic reasons (table 1.) Although difficult to document due to is frequently verbal nature, this is curious phenomenon considering the lack of evidence, particularly among strength athletes, who are widely known to pursue additional dietary protein for performance or body composition purposes (7).
It is important to point out that quotes listed intable 1 are not necessarily incorrect and may be followed or preceded by qualifying language. The statements do reflect an element of dissuasion (considering that overconsumption or excess of any nutrient is unhelpful or risky) and/or uncertainty (considering that studies present conflicting data or no information exists). Although the controversy is difficult to document, dissuasive viewpoints...