by Irene Martínez
What is Acne ?
Acne vulgaris, a skin condition, is marked by excessive sebum production by sebaceous glands, along with inflammation and hyperproliferation of Propionibacterium acnes, a bacterium found on our skin.(1). The resulted skin lesions are called comedones which are related to the pilosebaceous unit. This unit includes a hair follicle and a sebaceous gland, mostly found on the face and upper parts of the body. An excess of keratin, a protein present in the outer layer of skin, combined with sebum produced by sebaceous glands, clogs the opening of the hair follicle, leading to a comedo.
It is one of the most common dermatological conditions, especially among adolescents.
Androgens, hormones present in both sexes that increase during puberty, appear to stimulate the sebaceous glands, potentially leading to mild to severe acne during this period. (1).
Does diet really affect Acne?
Although many studies provide evidence supporting the association between food and acne development or aggravation, further investigation is needed to confirm the dietary influence on acne. Attention is primarily focused on high-glycemic diets and milk, as well as chocolate and vitamins.
First, some studies suggest that acne may develop in populations that changed dietary habits from rural or traditional areas to the Western nutritional style. Observations show that areas not affected by the Western diet experience a less frequent incidence of acne.
Glycaemic index
Glycaemic index (GI) is a ranking system for food containing carbohydrates according to how they increase glucose (sugar) in blood levels(2). Commonly, the Western diet is rich in carbohydrates with a high GI, which means a fast release of glucose in blood, leading to elevated insulin levels, the hormone that promotes its absorption. Hyperinsulinemia results in a cascade of reactions that stimulate the androgens’ secretion and consequently the sebum secretion(1).
Trying to replace high GI foods (e.g. white sugar, white bread and rice) with medium to low GI foods (e.g. beans, fruit and vegetables) could help the blemish-prone skin. While vitamin A and E (antioxidants) are suggested to reduce comedone formation, incorporating high-fiber foods into your diet can also aid in regulating insulin and balancing hormones.
Milk
Many studies have also addressed milk. It derives from cows and exposes us to the effect of hormones produced to stimulate the growth, also elevating insulin levels. Milk hormones serve as androgen precursors that can transform into androgens, the acnegenic factor described earlier. Observational studies suggest that it imparts a higher risk of acne. However, randomized controlled trials are necessary before milk restriction diet can be made(4).
Chocolate
Consumption of chocolate is a controversial topic. Some studies on the effect of chocolate are inaccurate due to additional ingredients in it.(5). Dark chocolate contains less milk and more antioxidants than milk chocolate. This lead to much smaller comedogenic effects, but there is still no clear answer(6).
Nevertheless, a randomized cross-over study assessed the development of new acne lesions following ingestion of chocolate versus a nonchocolate candy. The participants were 54 college students, randomly assigned to receive a milk chocolate bar or jellybeans (control group). The chocolate consumption group showed a statistically significant increase in acne lesions compared with the jellybean consumption group.(7). Furthermore, Netea et al demonstrated chocolate has an active role in over inflammation, which is an important contributor to acne pathogenesis(8).
In conclusion
In summary, considering the evidence together suggests an association between diet and acne. However, diet has not been demonstrated to cause acne. There’s evidence that it influences this condition to some degree. However, there are gaps in the literature and limitations in research. This situation should challenge dermatologists to design a quality research in order to develop dietary interventions for acne treatment.
So, do we need to worry every time we eat a chocolate candy or a huge pasta dish? Not necessarily. Despite decades of research, there is still little proof, and the effects depend also on the individual. What can we do to diminish the apparition of new acne lesions? The best solution is to follow a diet rich in antioxidants, fresh fruits and vegetables, fish and seafood, with low-fat meat and low glycaemic load.
