Diet and Acne & Rosacea
Alan Shalita, MD
In this presentation, Dr Shalita discusses the role of one’s diet and its relationship to acne and rosacea. Unfortunately, there is not a lot of information about diet and acne; however, there is a tremendous amount of interest in this subject. Dr Whitney Bowe conducted various aspects of this review, during the time she spent at SUNY Downstate with Dr Shalita.
With regards to rosacea, recent research by Dr. Richard Gallo and co-workers suggests an important role for innate immunity. Patients should avoid foods that cause vasodilatation, e.g. spicy, hot, etc. This has not been demonstrated in clinical trials; however, Dr Shalita feels it is something that should be studied.
Acne and Diet
Historically, any food that teenagers enjoyed were said to provoke or aggravate acne, e.g. chocolate, sodas, french fries, other candy. We know that the common denominator was that all of these foods were rich in sugars. In the 1970’s, Fulton et al conducted a study looking at chocolate bars versus control bars (carob), and they found no difference, i.e., both had same sugar and fatty acid content. The glycemic index between both bars was about the same. The researchers concluded that chocolate does not cause acne.
Dr Anderson studied 27 students assigned to consume chocolate, peanuts, milk or coca cola for one week. He, too, found no relationship to acne; however, the study was too short, underpowered, there were no lesion counts and no statistics.
In 1931, published in the British Journal of Dermatology, Dr Campbell showed that there was impaired glucose tolerance in patients with acne. In 1951, Dr Belisario, who published research in the Australian Journal of Dermatology, found that acne patients should avoid excessive carbohydrates and food that was high in sugar. Unfortunately, these reports were largely ignored. More recently, the relationship between diet and acne has been called back into question. It appears that carbohydrates and dairy products are considered by some to be the “real offenders.”
Researchers are examining the glycemic index and the glycemic load of various foods.
Examples of Low and High Glycemic Foods
In more recent studies, Dr Cordain et al, in 2002, examined 1300 subjects in Kitavan Islanders of Papua New Guinea or Ache hunter-gatherers of Paraguay. The researchers found no acne among the subjects. The reason, they feel, is due to diets low in carbohydrates and low glycemic loads. There are ways to criticize this study, in that, there were no controls and perhaps this group is not genetically predisposed to acne. Nonetheless, their conclusions led them to believe that the western diet may lead to hyperinsulinemia resulting in hormonal effects on acne.
A studied conducted in Australia by Dr Smith among students with acne found a positive correlation between glycemic index and acne; yet, a study by Dr Kaymak et al, in Turkey found no relationship in acne patients with a high carbohydrate load versus those on a low carbohydrate diet.
Dr Brian Berman, at the University of Miami, conducted a preliminary study looking at the South Beach Diet. In a survey, individuals who were on the South Beach Diet claimed to have had less acne.
It is important for Dermatologists to remember that a true low-carbohydrate diet can be very difficult to follow and requires very careful monitoring. Patients may benefit from food diaries and reminders. Dr Shalita mentions that he has seen a failure in compliance among the Caribbean population at Downstate because they do not want to give up certain foods.
Many believe in the effect of dairy on acne because of the hormones; however, it may very well be due to the sugar in the diary products. In 2005, a paper published in JAAD, showed the correlation between dairy products and acne. Dr Shalita believes that it may be due to the sugar content but this has not been confirmed.
There are other dietary factors that have been studied such as zinc. Dr Shalita conducted a study many years ago looking at whether or not zinc could be beneficial in acne. The study looked at students in a reform school in Hartford, CT. It was a placebo washout study and demonstrated that after one month of placebo there was a 50% improvement, so the question is could they have gotten better if they had taken zinc? They did not.
Vitamin A, when taken in high doses, can have the same effect as isotretinoin. No one has established whether or not fish oil and antioxidants have an effect on acne.
In conclusion, there may very well be a role for diet and acne, but at this point we do not know what it is. Dr Shalita suspects that it is related to the glycemic index of foods, but further studies are needed.