The negative effects seem to lie in the capacity
of some foods / nutrients to stimulate proliferative pathways that in turn stimulate development
of acne — suspect foods include those with a
high glycaemic load and milk.11, 43, 44 Other evidence comes from several studies reporting that the prevalence
of acne varies significantly between different populations and is
substantially lower in non-Westernized populations that follow traditional diets, 45 a common factor among these traditional diets being a low glycaemic load.46 Various studies have provided evidence that
high - glycaemic - load diets are implicated in the aetiology
of acne through their capacity to stimulate insulin, androgen bioavailability and insulin - like growth factor - 1 (IGF - 1) activity, whereas the beneficial effects
of low - glycaemic - load diets, apart from weight and blood glucose
levels, also include improved skin quality.44 The clinical and experimental evidence does in fact suggest ways in which insulin can increase androgen production and affect via induction
of steroidogenic enzymes, 47 the secretion by the pituitary gland
of gonadotropin - releasing hormone and the production
of sex hormone - binding globulin.48 Insulin is also able to reduce serum
levels of IGF - binding
protein - 1 increasing the effect
of IGF - 1.49 These insulin - mediated actions can therefore influence diverse factors that underlie the development
of acne such as: