The Skin Clinic Fremantle | Dr Sarah Boxley


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Does chocolate cause acne?

As a primary care skin clinic we see a lot of acne patients and this question gets asked frequently. Since it’s Easter we thought we’d bring it up again and have a look at the latest evidence.

So, does chocolate cause acne? Despite lots of studies, the scientific and medical communities are still not sure. The answer at the moment is “well, it’s complicated”. Let’s delve deeper…

There are plenty of good, robust studies that suggest that high glycemic index (GI) foods – ie those rich in refined carbohydrates and sugar, including sugary drinks, processed breads, snacks and “junk food” – are bad for acne-prone skin[1-3]. High GI foods cause a quick spike in blood sugar, which makes the body produce more insulin, as well as an insulin-like growth factor and hormones known as androgens. All these things lead to more sebum (oil) production in the skin, and to increased growth of the skin around the hair follicles which serves to trap the sebum. This then leads to blackheads, whiteheads and pimples.

So we know foods with a high sugar load are bad, but where does chocolate fit in? Previous research has dodged a link between chocolate and acne, including one study back in 1969[4] that was actually supported by the Chocolate Manufacturers Association of the USA. However, more recent studies indicate that it may indeed be a contributing factor. 

In 2016, separate groups of university students in the US were randomly assigned to eat a chocolate bar or 25 jelly beans, both of which provided the same glycemic load[5]. Interestingly, the jelly beans didn’t have an effect on acne. But when people ate chocolate, their pimples increased.

“We found that, on average, people had about five more pimples with the ingestion of chocolate,” said study author Dr. Gregory R. Delost of the Department of Dermatology at University Hospitals, Cleveland Medical Center. “Some people might say, five pimples, no big deal, but if someone is getting ready for their high school dance … then five pimples is definitely clinically relevant in that situation.”

One confounding factor in the “jelly bean v chocolate” study is that they used milk chocolate, which has a higher sugar content than dark chocolate and obviously some dairy in there too.

So let’s look at another study from back in 2011, where the participants were given 100% pure chocolate in the form of capsules, with no added milk or sugar. The study was small but was double-blinded and placebo-controlled. It showed that ingestion of pure chocolate in capsule form caused a greater increase than placebo in the number of inflammatory and non-inflammatory acne lesions in young men who had a history of acne but who had no acne lesions at baseline[6].

Moving on to yet another study, again from 2016 but this time using 99% dark chocolate…. A group of 25 acne-prone men were asked to consume 25g daily for 4 weeks. Statistically significant changes of acne scores and numbers of comedones (whiteheads) and inflammatory papules were detected as early as 2 weeks into the study. At 4 weeks, the changes remained statistically significant compared to baseline[7]. This study was also a small one and did not include a control group or female participants, who are more difficult to study because of their cyclical hormonal changes which we know can impact on their acne scores. It does not address whether chocolate can cause acne in those who are not acne-prone, but it does suggest that dark chocolate can exacerbate acne that those what are already prone to it.

So, in milk chocolate, the dairy and/or sugar might be involved in aggravating acne, but in the case of dark chocolate, it could be the various fatty ingredients rather than the chocolate itself. The cocoa butter in dark chocolate contains fats known as stearic acid and oleic acid, which have been shown to be involved in the pathogenesis of inflammatory acne [8].

In addition to the fat component of chocolate, which has been linked to blackheads, some research suggests that chocolate may have pro-inflammatory influences in the skin, which could contribute to inflammatory acne, characterized by red papules and pustules, especially in the presence of known acne-causing bacteria.

Other researchers have looked at whether chocolate affects skin differently at different ages, by dividing men into “young” and “middle-aged” groups who were all given 10g per day of dark chocolate for 4 weeks[9]. They reported that chocolate consumption caused a significant increase in shedding of the top layer of skin but only in the group of young men. They also found that the presence of acne-causing bacteria on the skin significantly increased in both the young and middle-aged men, though this effect was noticeably stronger in the young men. 

But isn’t chocolate meant to be good for you? Cocoa contains molecules called “flavonoids”, which are known to be anti-inflammatory and could theoretically be beneficial to the skin. Cocoa beans fresh from the tree are exceptionally rich in flavanols. Unfortunately, during conventional chocolate making, this high antioxidant capacity is greatly reduced due to manufacturing processes [10]. Studies are currently ongoing in to whether these antioxidant properties can be preserved and utilised for both improvement in skin function and for sun protection.

Further investigation is needed if we are going to work out the exact link between chocolate and acne, but for each individual patient, knowing how your own skin reacts to chocolate will give you all the information you need. Keeping a food journal can help you work out whether your acne worsens when you eat chocolate. Unfortunately, that may mean giving up the indulgence, at least some of the time, or limiting the amount you eat. Every skin reacts to dietary influences slightly differently and every body has its own triggers. The bottom line is, if chocolate breaks you out, you should consider not eating it 🙁

Dr. Sarah Boxley MBBS BSc MRCGP FRACGP FSCCA FACAM

Bibliography

1. Melnik, B.C. and G. Schmitz, Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris. Exp Dermatol, 2009. 18(10): p. 833-41.

2. Melnik, B.C., Linking diet to acne metabolomics, inflammation, and comedogenesis: an update. Clin Cosmet Investig Dermatol, 2015. 8: p. 371-88.

3. Melnik, B.C., Acne vulgaris: The metabolic syndrome of the pilosebaceous follicle. Clin Dermatol, 2018. 36(1): p. 29-40.

4. Fulton, J.E., Jr., G. Plewig, and A.M. Kligman, Effect of Chocolate on Acne Vulgaris. JAMA, 1969. 210(11): p. 2071-2074.

5. Delost, G.R., M.E. Delost, and J. Lloyd, The impact of chocolate consumption on acne vulgaris in college students: A randomized crossover study. J Am Acad Dermatol, 2016. 75(1): p. 220-2.

6. Block, S.G., et al., Exacerbation of facial acne vulgaris after consuming pure chocolate. J Am Acad Dermatol, 2011. 65(4): p. e114-e115.

7. Vongraviopap, S. and P. Asawanonda, Dark chocolate exacerbates acne. Int J Dermatol, 2016. 55(5): p. 587-91.

8. Li, W.H., et al., In vitro modeling of unsaturated free fatty acid-mediated tissue impairments seen in acne lesions. Arch Dermatol Res, 2017. 309(7): p. 529-540.

9. Chalyk, N., et al., Continuous Dark Chocolate Consumption Affects Human Facial Skin Surface by Stimulating Corneocyte Desquamation and Promoting Bacterial Colonization. J Clin Aesthet Dermatol, 2018. 11(9): p. 37-41.

10. Andres-Lacueva, C., et al., Flavanol and flavonol contents of cocoa powder products: influence of the manufacturing process. J Agric Food Chem, 2008. 14: p. 56.