Hormis le lactose, c'est l'effet anabolique de la whey qui peut aggraver l'acné chez certains
Acne and Whey Protein Supplementation among Bodybuilders.
Dermatology. 2012;225(3):256-8. Simonart T.
Accumulative evidence supports the role of nutritional factors in acne. I report here 5 healthy male adult patients developing acne after the consumption of whey protein, a favorite supplement of those engaged in bodybuilding. These observations are in line with biochemical and epidemiological data supporting the effects of milk and dairy products as enhancers of insulin/insulin-like growth factor 1 signaling and acne aggravation. Further prospective studies are required to determine the possible role of dietary supplements in the fitness and bodybuilding environment.
Evidence for acne-promoting effects of milk and other insulinotropic dairy products.
Nestle Nutr Workshop Ser Pediatr Program. 2011;67:131-45. Melnik BC.
Acne vulgaris, the most common skin disease of western civilization, has evolved to an epidemic affecting more than 85% of adolescents. Acne can be regarded as an indicator disease of exaggerated insulinotropic western nutrition. Especially milk and whey protein-based products contribute to elevations of postprandial insulin and basal insulin-like growth factor-I (IGF-I) plasma levels. It is the evolutional principle of mammalian milk to promote growth and support anabolic conditions for the neonate during the nursing period. Whey proteins are most potent inducers of glucose-dependent insulinotropic polypeptide secreted by enteroendocrine K cells which in concert with hydrolyzed whey protein-derived essential amino acids stimulate insulin secretion of pancreatic β-cells. Increased insulin/IGF-I signaling activates the phosphoinositide-3 kinase/Akt pathway, thereby reducing the nuclear content of the transcription factor FoxO1, the key nutrigenomic regulator of acne target genes. Nuclear FoxO1 deficiency has been linked to all major factors of acne pathogenesis, i.e. androgen receptor transactivation, comedogenesis, increased sebaceous lipogenesis, and follicular inflammation. The elimination of the whey protein-based insulinotropic mechanisms of milk will be the most important future challenge for nutrition research. Both, restriction of milk consumption or generation of less insulinotropic milk will have an enormous impact on the prevention of epidemic western diseases like obesity, diabetes mellitus, cancer, neurodegenerative diseases and acne.
Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris.
Exp Dermatol. 2009 Oct;18(10):833-41 Melnik BC, Schmitz G.
It is the purpose of this viewpoint article to delineate the regulatory network of growth hormone (GH), insulin, and insulin-like growth factor-1 (IGF-1) signalling during puberty, associated hormonal changes in adrenal and gonadal androgen metabolism, and the impact of dietary factors and smoking involved in the pathogenesis of acne. The key regulator IGF-1 rises during puberty by the action of increased GH secretion and correlates well with the clinical course of acne. In acne patients, associations between serum levels of IGF-1, dehydroepiandrosterone sulphate, dihydrotestosterone, acne lesion counts and facial sebum secretion rate have been reported. IGF-1 stimulates 5alpha-reductase, adrenal and gonadal androgen synthesis, androgen receptor signal transduction, sebocyte proliferation and lipogenesis. Milk consumption results in a significant increase in insulin and IGF-1 serum levels comparable with high glycaemic food. Insulin induces hepatic IGF-1 secretion, and both hormones amplify the stimulatory effect of GH on sebocytes and augment mitogenic downstream signalling pathways of insulin receptors, IGF-1 receptor and fibroblast growth factor receptor-2b. Acne is proposed to be an IGF-1-mediated disease, modified by diets and smoking increasing insulin/IGF1-signalling. Metformin treatment, and diets low in milk protein content and glycaemic index reduce increased IGF-1 signalling. Persistent acne in adulthood with high IGF-1 levels may be considered as an indicator for increased risk of cancer, which may require appropriate dietary intervention as well as treatment with insulin-sensitizing agents.