What's the scoop on diet and acne?

In our blog, Toronto dermatologist Dr. Michelle Levy writes about common skin problems, controversies and developments, and provides science-based answers to common questions.

One of the most frequent questions I get in my practice as a dermatologist from is about whether or not someone’s diet is causing their acne.  Interestingly, the dermatologic community's thoughts on this issue have gone back and forth over the past few decades.  Today, there appears to be increasing scientific evidence that diet may play a role in exacerbating acne.

It was once thought that, because those with acne often have oily skin, eating oily, greasy foods might make acne worse.  This gave rise to the commonly-held belief that eating chocolate or pizza will cause acne to flare.  Flawed studies conducted decades ago seemed to support this, until better studies done more recently put this to rest; eating fat does not cause acne.

Acne is caused by genetic and hormonal factors. Usually, one’s diet does not cause acne, but may contribute to its severity. This is still somewhat controversial, and more research needs to be done to elucidate exactly which dietary factors make acne worse and how modifying one’s diet can be helpful.

Dairy and acne:

Milk contains hormones such as androgens and insulin-like growth factor 1 (IGF-1), which are postulated to contribute to acne by leading to increased production of sebum and blockage of hair follicles.  Several studies in which researchers surveyed large groups about their diets and whether they had certain health conditions found a link between consuming dairy products and acne, most significantly between skim milk.  Skim milk was correlated with acne on more than one occasion, possibly because skim milk contains different levels of hormones.  All of these studies are limited by their design; they show a correlation between dairy and acne but are not able to prove that drinking milk or eating dairy products causes acne. In all cases, the associations between milk consumption and acne were weak, and this evidence is not sufficient to make firm recommendations. Whey supplements, which contain dairy, have been shown to exacerbate acne.

Glycemic Load:

The glycemic index refers to a rating given foods based on how much they cause blood sugar (glucose) levels to rise, while the glycemic load takes in to account both the glycemic index and the carbohydrate content/serving size, for an estimate on a food's impact on blood sugar.  A glycemic index diet is a diet based on how foods affect your blood sugar.  High glycemic foods include those that are high in certain carbohydrates, such as sugar or white flour, as well as white potatoes and white rice.  A more detailed explanation of this type of diet can be found here, and a list of the glycemic index of many common foods can be found on this site.

Some scientists theorize that these foods cause high levels of the hormone insulin, which leads to increases in IGF-1 and increased sebum production.  Insulin also raises levels of androgens (male hormones) that are known to contribute to acne.

Two small studies have evaluated whether or not eating a low glycemic diet could improve acne symptoms.  In these studies, participants who ate low-glycemic diets for 12 weeks had improvement in their acne.  The studies were short in duration and we don't know if this improvement is sustained over longer periods of time.

Other studies have shown that those whose diet is rich in sugary foods, sodas, bread and rice have higher rates of acne than those whose diets are based on fruits and vegetables.  Like the dairy studies, studies using questionnaires of what people eat are limited in that they can not prove causation.

References:

Dairy:

  1. Davidovici B, Wolf R. "The role of diet in acne: facts and controversies." Clinics in Dermatology. 2010 Jan-Feb; 28(1): 16-6.

  2. Bowe W, Joshi S, Shalita A. "Diet and acne." Journal of the American Academy of Dermatology. 2010 Jul; 63(1): 121-41.

  3. Danby F. "Acne and milk, the diet myth, and beyond." Journal of the American Academy of Dermatology. 2005; 52: 360-2.

  4. Adebamowo C, et. al. "High school dietary dairy intake and teenage acne." Journal of the American Academy of Dermatology. 2005; 52: 207-14.

  5. Adebamowo C, et. al. "Milk consumption and acne in adolescent girls." Dermatology Online Journal. 2006; 12(4): 1.

  6. Adebamowo C, et. al. "Milk consumption and acne in teenaged boys." Journal of the American Academy of Dermatology. 2008; 58: 787-93.

  7. Ismail NH, Manaf ZA, Azizan NZ. "High glycemic load diet, milk and ice cream consumption are related to acne vulgarism in Malaysian young adults: a case control study." BMC Dermatology. 2012; 12: 13.

  8. Salomone C, et al. "Comparative study of dietary habits between acne patients and a healthy cohort." Indian Journal of Dermatology, Venereology and Leprology. 2012; 78(1): 99-101.

Glycemic Load:

  1. Smith R, Brane A, Varigos G, Mann N. "The effect of a low-glycemic load diet on acne vulgaris and the fatty acid composition of skin surface triglycerides." Journal of Dermatological Science. 2008 Apr; 50(1): 41-52.

  2. Nam S, et. al. "Effect of obesity in total and free insulin-like growth factor (IGF)-1, and their relationship to IGF-binding protein (BP)-1, IGFBP-2, IGFB'I-3, insulin, and growth hormone." International Journal of Obesity. 1997; 21: 355-359.

  3. Brismar K, Ferngvist-Forbes E, Wahren J, Hall K. "Effect of insulin on the hepatic production of insulin-like growth factor - binding protein-1 (IGFBP-1), IGFBP-3, and IGF-1 in insulin-dependent diabetes." The Journal of Clinical Endocrinology & Metabolism. 1994; 79: 872-878.

  4. Evens T, Kaye S. "Retinoids: present role and future potential." British Journal of Cancer. 1999; 80:1-8.

  5. Kumari R, Thappa DM. "Role of insulin resistance and diet in acne." Indian Journal of Dermatology, Venereology, and Leprology. 2013; 79(3): 291-9.

  6. Melnic BC, Zouboulis CC. "Potential role of Fox01 and mTORC1 in the pathogenesis of Western diet-induced acne." Experimental Dermatology. 2013; 22(5): 311-5.

  7. Del Prete M, et al. "Insulin resistance and acne: a new risk factor for men?" Endocrine. 2012; 42(3): 555-60.

  8. Attia N, et. al. "The metabolic syndrome and insulin-like growth factor I regulation in adolescent obesity. The Journal of Clinical Endocrinology & Metabolism. 1998; 83: 1467-1471.

  9. Yang Q, et. al. "Biallelic inactivation of retinoic acid receptor B2 gene by epigenetic change in breast cancer." The American Journal of Pathology. 2001; 158: 299-303.

  10. Liu B, et. al. "Direct functional interaction between insulin-like growth factor-binding protein-3 and retinoid X receptor-alpha regulate transcriptional signaling and apoptosis." The Journal of Biological Chemistry. 2000; 275: 33607-33613.

  11. Wendling O, Chambon P, Mark M. "Retinoid X receptors are essential for early mouse development and placentogenesis." Proceedings of the National Academy of Sciences of the United States of America. 1999; 96: 547-551.

  12. Chiba H, Clifford J, Metzger D, Chambon P. "Distinct retinoid X receptor-retinoic acid receptor heterodimers are differentially involved in the control of expression of retinoid target genes in F9 embryonal carcinoma cells." Molecular and Cellular Biology. 1997; 17: 3013-3020.

  13. Grimberg A, Cohen P. "Role of insulin-like growth factors and their binding proteins in growth control and carcinogenesis." Journal of Cellular Physiology. 2000, 183: 1-9.

  14. Thacher S, Vasudevan J, Chandraratha R. "Therapeutic applications for ligands of retinoid receptors." Current Pharmaceutical Design. 2000; 6: 25-58.

  15. Eichenfield L, Layden J. "Acne: current concepts of pathogenesis and approach to rational treatment." Pediatrician. 1991; 18: 218-223.

  16. Thiboutot D. "Acne: an overview of clinical research findings." The Dermatology Clinic. 1997; 15: 97-109.

  17. Danby FW. "Turning acne on/off via mTORC1." Experimental Dermatology. 2013; 22(7): 505-6.

  18. Melnic BC, John SM, Plewig G. "Acne: risk indicator for increased body mass index and insulin resistance." Acta Dermato-Venereologica. 2013; 93(6): 644-9.

  19. Smith R, et. al. "The effect of a high protein, low-glycemic-load diet versus a conventional, high glycemic-load diet on biochemical parameters associated with acne vulgaris: A randomized, investigator-marked, controlled trial." Journal of the American Academy of Dermatology. 2007; 57: 247-56.

  20. Salomone C, et al. "Comparative study of dietary habits between acne patients and a healthy cohort." Indian Journal of Dermatology, Venereology and Leprology. 2012; 78(1): 99-101.

  21. Ismail NH, Manaf ZA, Azizan NZ. "High glycemic load diet, milk and ice cream consumption are related to acne vulgarism in Malaysian young adults: a case control study." BMC Dermatology. 2012; 12: 13.

Michelle Levy

Dr. Michelle Levy is a board-certified dermatologist specializing in medical and aesthetic dermatology. A graduate of the University of Toronto's Faculty of Medicine, Dr. Levy provides a full spectrum of dermatologic services in Toronto, Canada. Education: M.D., University of Toronto, 1999 Residency in Dermatology, University of Toronto, 1999-2004 Employment History: Self-employed, North York, Ontario, 2005-Present Medcan. Consultant Dermatologist. 2007-Present