Oral Supplements to Treat Atopic Dermatitis: What is The Quality of the Evidence?
Many patients with atopic dermatitis (AD) are seeking a “natural” remedy to treat the itch and discomfort that comes with this chronic illness. However, the lack of evidence on the effectiveness of such treatments may cause patients to waste money and effort on ineffective treatments or even jeopardize their health with dangerous treatments.
A recent study highlighted some commonly used oral supplements and detailed the data that is known about how they may affect AD symptoms and disease severity. Probiotics are one of the oral supplements that have gained popularity, mostly because of promising research on their effectiveness in other diseases. However, after looking at a recent meta-analyses and Cochrane reviews, the authors conclude that with the available evidence, they are unable to recommend probiotics and synbiotics as AD treatment. They note that they are generally safe and well tolerated, and may represent a possible therapeutic intervention in the future.
The results are similar for other dietary supplements including fish oil, vitamin D, vitamin E, vitamin B6, zinc, selenium, docosahexaenoic acid, sea buckthorn oil, sunflower oil, and hempseed oils. There is simply a lack of data to support their use in treating AD.
Some oral supplements suffer from more than weak data on their effectiveness, as in the use of evening primrose oil and/or borage oil. Neither were found to be more effective than a placebo in a meta-analysis and the possible side effects outweigh the benefits. On the riskier side, the authors single out Chinese herbal medicine, and oral Ayurvedic medications due to the lack of quality control and transparency with respect to ingredients.
Overall, the authors conclude that the safest and most effective natural agents remain topically applied emollients. The evidence to support the use of oral supplements is not there yet, most studies about oral supplements are small scale with frequently conflicting results and often poor methodologic quality.