The addition of picolinic acid to low protein diets — a word of caution

The potential value and toxicity of chromium picolinate as a nutritional supplement, weight loss agent and muscle development agent

The element chromium apparently has a role in maintaining proper carbohydrate and lipid metabolism in mammals. As this role probably involves potentiation of insulin signalling, chromium dietary supplementation has been postulated to potentially have effects on body composition, including reducing fat mass and increasing lean body mass. Because the supplement is absorbed better than dietary chromium, most studies have focused on the use of chromium picolinate [Cr(pic)(3)]. Cr(pic)(3) has been amazingly popular with the general public, especially with athletes who may have exercise-induced increased urinary chromium loss; however, its effectiveness in manifesting body composition changes has been an area of intense debate in the last decade. Additionally, claims have appeared that the supplement might give rise to deleterious effects. However, over a decade of human studies with Cr(pic)(3) indicate that the supplement has not demonstrated effects on the body composition of healthy individuals, even when taken in combination with an exercise training programme. Recent cell culture and in vivo rat studies have indicated that Cr(pic)(3) probably generates oxidative damage of DNA and lipids and is mutagenic, although the significance of these results on humans taking the supplement for prolonged periods of time is unknown and should be a focus for future investigations. Given that in vitro studies suggest that other forms of chromium used as nutritional supplements, such as chromium chloride, are unlikely to be susceptible to generating this type of oxidative damage, the use of these compounds, rather than Cr(pic)(3), would appear warranted. Potential neurological effects (both beneficial and deleterious) from Cr(pic)(3) supplementation require further study.

Effects of epidermal growth factor dosage forms on mice full-thickness skin wound zinc levels and relation to wound strength

Epidermal growth factor (EGF) and zinc promote re-epithelization and reparative tissue strength by enhancing deposition of collagen at the site of the wound. In this study two EGF dosage forms were chosen to assess the effect of zinc levels on wound healing and for comparison with wound tear strengths. A solution of EGF in 0.9% w/v NaCl and an EGF gel in 0.2% Carbopol 940 polymer (5 microL) were applied to full-thickness skin wounds of mice twice a day for 7 and 15 days. Wound zinc levels were higher on day 7 than on day 15, especially in wounds treated with EGF. The wound zinc levels of the gel + EGF group on day 15 were similar to those of normal control skin. These results imply that there is a close connection, but no direct relationship, between EGF application in both dosage forms and wound zinc levels during healing.

Efficacy of chromium supplementation in athletes: emphasis on anabolism

As the biologically active component of glucose tolerance factor (GTF), the essential trace mineral chromium is now being marked to athletes. GTF potentiates insulin activity and is responsible for normal insulin function. Thus, insulin's effects on carbohydrate, fat, and protein metabolism are dependent upon the maintenance of adequate chromium stores. Due to excessive chromium loss and marginal chromium intake, athletes may have an increased requirement for chromium. Therefore, in some circumstances the dietary supplementation of a chromium compound may be efficacious. The restoration and maintenance of chromium stores via supplementation would promote optimal insulin efficiency, necessary for high-level athletic performance. However, potential anabolic effects of enhanced insulin function would likely be marginal, and reports of short-term anabolic increases from the supplementation of an organic chromium compound need to be confirmed.