Comparative study of dietary habits between acne patients and a healthy cohort

Claudia Salomone, Claudia Nicklas, Cristián Navarrete-Dechent, Katherine Droppelmann, María Luisa Pérez-Cotapos

 Department of Dermatology, Pontificia Universidad Católica de Chile, Chile

Correspondence Address:
Claudia Salomone
Department of Dermatology, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4686. Macul, Santiago
Chile

Sir,

Acne is the most common skin disease, affecting nearly 85% of the people at some time of their lives, being more frequent in adolescents. ^[1] Acne and diet have been historically associated, but this association is still very controversial. ^[1],[2]

Population studies suggest a lower prevalence of acne in rural populations compared with western civilizations, and an increase in acne lesions when a western style of life is adopted. ^[1] In the last decades, a series of prospective controlled trials have supported the association between specific dietary elements and acne. ^[2] An association between cow milk ingestion and high glycemic index foods and increase in acne lesions has been noted; inversely, low glycemic index diet could be associated with a reduction in the number of acne lesions. ^[1]

An analytic study was made in our Department of Dermatology between November 2009 and April 2010 to evaluate dietary habits in acne patients compared with a healthy cohort to search for possible associations of certain food products with acne.

Every patient who consulted in our center with the diagnosis of acne vulgaris with age between 13 and 25 years was invited to participate in this study. Informed consent was signed.

A healthy cohort (control group) of 40 patients was recruited with age between 13 and 25 years. Sex, age and body mass index (BMI) were consigned. In the acne group, severity and extension of the disease, evolution time and treatment received were evaluated. We also recorded the presence of acne exacerbations attributed to stress, menstruation and specific foods, reported by patients with acne.

An alimentary survey was applied to every patient in both groups and included specific foods and its ingestion proportions in a normal week. Some of the surveyed foods were chocolates, carbonated drinks, juices, sweets, cakes, pies, junk food, milk and milk products, dried fruits, bread, white rice, potatoes, fish and shellfishes, fruits and vegetables.

Statistical analysis was made with the non-parametric Mann-Whitney test using STATA 10.0. Statistically significant results were considered when a P-value was ≤0.05.

A total of 40 patients were included in the acne group. [Table - 1] lists the patient′s baseline characteristics. No statistically significant differences were found between both groups. Mean duration of acne in the participants was 2.7 years.

Seventy percent of acne patients noted an increase in acne lesions with stress, and 42% noticed an exacerbation with menstrual period.

In the acne group, 58% noticed an exacerbation with foods, particularly dairy, mayonnaise and butter in 30%, chocolate in 27% and nuts in 12.5%.

Comparing both groups′ alimentary habits, the acne group referred greater ice cream ingestion (75% versus 47%, P = 0.021), juices with sugar (65% versus 35%, P = 0.007), carbonated drinks (67% versus 47%, P = 0.05), milk (97% versus 82%, P = 0.028), bread (95% versus 72%, P = 0.013) and white rice (100% versus 90%, P = 0.05). Also, a lower consumption of fruits (85% versus 97.5%, P = 0.05) and vegetables (75% versus 97.5%, P = 0.03%) were noted in the acne group.

Patient′s perception of dietary factors causing or exacerbating acne is common. ^[3] As reported elsewhere, more than 50% of our patients noted a food-related exacerbation in this study with dairy products, mayonnaise, butter, chocolate and nuts.

Our results support what is already reported in the literature, namely a higher consumption of milk and high glycemic index foods (ice creams, juices with sugar, carbonated drinks, bread and white rice) in acne patients compared with healthy individuals. It is worth noting a lower fruit and vegetables consumption in the acne group compared to the control group, to which can be interpreted as a protective factor for acne development in this latter group. This latter association is not well documented in the literature, ^[4] but we believe this point is remarkable not only for acne prevention and treatment but also to stimulate healthy habits in adolescents and young adults.

High glycemic index foods lead to hyperglycemia, reactive hyperinsulinemia and a resulting increase in insulin like growth-factor 1 (IGF-1) formation, increased androgens and an altered retinoid signaling pathway related to acne. ^[5] A low glycemic index diet decreases IGF-1 levels and improves acne. ^[1] Dairy products contains placenta-derived progesterone and dihydrotestosterone (DHT) precursors, including 5a-androstanedione and 5a-pregnanedione. Other compounds of milk are growth stimulating hormones and IGF-1, among others. ^[6] Milk increases IGF-1 levels by 10-20% in adults and 20-30% in children. ^[6]

The important proportion of patients with acne who relate stress and menstrual period to exacerbations is also remarkable, considering the role of hormones in acne. ^[4] Significant changes in follicular duct and even duct orifice blockages occur during menstrual period. ^[4]

Our study confirms what is published elsewhere [Table - 2], indirectly evidencing that alimentary habits may influence acne apparition and exacerbations. We propose patient education and counseling about the ingestion of these probably related foods as part of acne treatment. We also encourage patients to increase fruits and vegetables consumption.

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