Pimples and diet

Cordain et al (Archives of Dermatology 2002; 138: 1584-1590) have recently published a papers which hypothesises that a high Glycaemic Index (GI) diet combined with a high Glucose Load (GL) (as a result of a large serve of refined carbohydrates) may be linked to pimples and acne. Anecdotal evidence from dermatologists also suggests that using low-glycaemic load carbohydrates helps alleviate acne in some patients.

Cordain's paper notes the absence of acne in teenagers of modern day 'hunter-gatherer' societies (e.g Kitavan people in Papua New Guinea) who consume diets composed of minimally processed plant and animal foods. In contrast, 60-95% of teenagers of Westernised populations (e.g USA) with more refined diets suffer from acne.

Pimples/acne is caused by the following sequence of events:
1. hyperkeratinization of the skin
2. obstruction of sebaceous (oil producing) follicles in the skin caused by an abnormal build-up of follicular cells
3. Increased sebum (oil) production
4. Colonisation of the follicle by bacteria which thrive on the sebum and in turn cause inflammation

Diets with a high GL may result in acute or chronically elevated insulin levels which:
1. aggravate hyperkeratinization and build up of follicular cells by elevating levels of the insulin-like growth factor IGF-1 and by reducing levels of the insulin-like growth factor binding protein IGFBP-3.
2. activate a hormone sequence that increases the synthesis of androgens in the ovaries or testes. Higher levels of insulin, IGF-1 and androgens may then increase sebum production .

A study at the Royal Melbourne Institute of Technology (RMIT) has commenced under the direction of Dr Neil Mann to prove if high protein low glycaemic load diets improves acne in teenage boys.

In the meantime, if you suffer from acne try eating less refined high GI foods and more unrefined low GI foods.

Please note: GL is based on the Glycaemic Index of the food/meal and the total amount of carbohydrate in the serve/meal consumed. This concept is important because some low GI foods can contain a large amount of total carbohydrate due to the large serving size that can be consumed - for example orange juice. If a food/meal has a low GI and a moderate amount of total carbohydrates it will have a low GL.

Last Updated: October 2003.