Acne is the most common skin condition in the U.S. About 85% of people in the Western world experience acne during their teenage years, but it can occur at any age. Acne is more than just pimples - it can leave permanent scars, and in many people, acne (even if it is not severe) can seriously affect quality of life, causing low self-esteem, withdrawal from social situations, anxiety, and depression.1
What causes acne?
There are four major components of acne: excessive production of oil by the skin, skin cells dividing excessively (hyperproliferation), bacteria, and inflammation.2 A pimple or lesion forms when a pore in the skin begins to clog with old, dead skin cells. Usually these cells are simply shed from the surface of the skin, but if too much oil is being produced, the dead cells can stick together and become trapped inside the pore. Bacteria also play a role – they can grow and multiply inside the pore, resulting in an inflammatory response.1
Does what we eat really affect acne?
For years doctors have proclaimed that diet has nothing to do with acne. That reflects the nutritional ignorance of physicians and their inexperience in treating disease with superior diet. Scientific studies have demonstrated that the diet is very important, because what we eat can affect the hormones that contribute to the oil production, hyperproliferation, and inflammation that cause acne. The acne-promoting dietary factors that have been most extensively studied are dairy products and high glycemic load foods – these factors influence hormonal (increase IGF-1 levels) and inflammatory factors increasing acne prevalence and severity.3,4
IGF-1: an important hormone that influences acne
Hormonal influences that affect insulin-like growth factor 1 (IGF-1) levels are key.5 Elevated IGF-1 levels lead to changes in gene expression that cause inflammation, hormonal changes, increased oil production, and development of acne lesions. Protein intake is the major factor that determines circulating IGF-1 levels, especially protein from dairy products. Read more in Dr. Fuhrman’s Healthy Times Newsletter on IGF-1.
A three-year prospective study of 9-15 year old girls found a 20% increase in acne prevalence in girls that had 2 or more servings of milk per day compared to less than 1 per week. This association held true for total, whole, low fat, and skim milk.6 The same researchers found a similar association in boys who drank skim milk (milk highest in protein).7 Furthermore, in the Nurses’ Health Study, dairy products eaten during high school were associated with acne during women’s teenage years.8
High glycemic load foods
Glycemic load (GL) is a measure of the effect of a certain food on blood glucose levels. High-GL foods like refined carbohydrates produce dangerous spikes in blood glucose, leading to excessive insulin levels in the blood (hyperinsulinemia), which contribute to diabetes, heart disease, and several cancers.9,10 Hyperinsulinemia not only promotes inflammation but also raises IGF-1 levels, further contributing to acne. A low glycemic load diet has been shown to improve acne symptoms, and decrease IGF-1 and skin oil production in several studies.11-13
Blood levels of zinc, carotenoids, and Vitamin E are known to be lower in acne patients compared to those without acne, suggesting that maintaining micronutrient adequacy may help to prevent acne.14,15 Carotenoids are abundant in green and orange vegetables, and vitamin E is abundant in nuts and seeds. Although pumpkin seeds and hemp seeds are rich in zinc, zinc absorption efficiency may be low on a plant-based diet, so a multivitamin and mineral supplement is recommended to assure optimal levels of zinc, iodine, Vitamin D and B12.
1. American Academy of Dermatology: Acne. http://www.aad.org/skin-conditions/dermatology-a-to-z/acne. Accessed June 29, 2011.
2. Costa A, Lage D, Moises TA: Acne and diet: truth or myth? An Bras Dermatol 2010;85:346-353.
3. Ferdowsian HR, Levin S: Does diet really affect acne? Skin Therapy Lett 2010;15:1-2, 5.
4. Melnik BC, Schmitz G: Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris. Exp Dermatol 2009;18:833-841.
5. Danby FW: Diet and acne. Clin Dermatol 2008;26:93-96.
6. Adebamowo CA, Spiegelman D, Berkey CS, et al: Milk consumption and acne in adolescent girls. Dermatol Online J 2006;12:1.
7. Adebamowo CA, Spiegelman D, Berkey CS, et al: Milk consumption and acne in teenaged boys. J Am Acad Dermatol 2008;58:787-793.
8. Adebamowo CA, Spiegelman D, Danby FW, et al: High school dietary dairy intake and teenage acne. J Am Acad Dermatol 2005;52:207-214.
9. Barclay AW, Petocz P, McMillan-Price J, et al: Glycemic index, glycemic load, and chronic disease risk--a meta-analysis of observational studies. Am J Clin Nutr 2008;87:627-637.
10. Gnagnarella P, Gandini S, La Vecchia C, et al: Glycemic index, glycemic load, and cancer risk: a meta-analysis. Am J Clin Nutr 2008;87:1793-1801.
11. Smith R, Mann N, Makelainen H, et al: A pilot study to determine the short-term effects of a low glycemic load diet on hormonal markers of acne: a nonrandomized, parallel, controlled feeding trial. Mol Nutr Food Res 2008;52:718-726.
12. Smith RN, Braue A, Varigos GA, et al: The effect of a low glycemic load diet on acne vulgaris and the fatty acid composition of skin surface triglycerides. J Dermatol Sci 2008;50:41-52.
13. Smith RN, Mann NJ, Braue A, et al: A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial. Am J Clin Nutr 2007;86:107-115.
14. El-Akawi Z, Abdel-Latif N, Abdul-Razzak K: Does the plasma level of vitamins A and E affect acne condition? Clin Exp Dermatol 2006;31:430-434.
15. Amer M, Bahgat MR, Tosson Z, et al: Serum zinc in acne vulgaris. Int J Dermatol 1982;21:481-484.