Skin and Diet
by Katta MD
SUPPLEMENTS FOR ECZEMA: THE GOOD AND THE BAD
1. Let's start with the promising: probiotics and prebiotics.
Probiotics are actually live micro-organisms, such as bacteria, that may improve health. These micro-organisms are either the same or similar to those that are found naturally in the human body. Some people refer to probiotics as "good bacteria." Humans have been consuming probiotics for centuries. Yogurt with live cultures is one of the most familiar probiotic foods, but there are plenty of others that are now sold. These include foods and beverages such as kefir, miso, kimchee, sauerkraut, and pickles with live cultures. Probiotics may be found naturally in certain foods, or they may be added to foods. They may also be available as over-the-counter supplements.
Probiotics have been studied for use in different allergic diseases because they may be able to change our gut flora. "Gut flora" refers to the types of bacteria that live in our intestines. Children who aren't prone to allergies have a different type of gut flora, and a more varied gut flora, than children with eczema.
Prebiotics are different substances that have also been studied for their use in allergic diseases. They're often studied in combination with probiotics. Prebiotics are foods or supplements that contain certain non-digestible ingredients. These ingredients seem to selectively stimulate the growth of "good bacteria". Some researchers refer to them as "fertilizer" for good bacteria. They're often in the form of oligosaccharides, and while they may be added as dietary supplements to foods or infant formula, they're found naturally in certain vegetables. Certain dietary fiber and inulin are considered prebiotics.
Here's the big question: If you're able to add "good bacteria" back into the digestive system, along with the "foods" that they love, could that help reduce inflammation and thereby help the skin of adults and children with eczema?
Results thus far are promising, although there's much more work to be done. In one analysis, which included the results of 6 different trials, the use of probiotics and prebiotics taken in combination appeared to be a promising addition to the therapy of patients with atopic dermatitis. Therapy appeared most promising when given for at least 8 weeks to adults and children over the age of 1 year, with the probiotics containing mixed strains of bacteria.
HOWEVER, the studies that have been done showed a wide variation in results. Some patients didn't improve at all, and some patients improved quite a bit. Different studies used different strains of bacteria in their probiotics, and at different doses. There's a lot more research to be done before recommendations can be made. What type of probiotics would be best? What dose? For how long? Which eczema patients are more likely to benefit? How can we prevent side effects? These unanswered questions are the main reason I can't recommend a particular probiotic supplement. If you head to the drugstore, there's many different bacterial strains and doses being sold, which is a reflection of the confusion that surrounds these issues.
I can, however, recommend food. (as long as you're not allergic to these foods!)
Foods that naturally contain probiotics have been eaten in other cultures for centuries, and many cultures have a strong belief that these foods promote health. Many of my Indian friends tell me that their families believe that daily intake of yogurt is very important for general wellness. Increasing your daily intake of probiotic foods is one easy strategy, and I'm planning to post more strategies for making your own probiotic foods.
Prebiotic foods are also recommended, and that means more fruits and vegetables, which are an important component of a general anti-inflammatory diet.
2. Next are two supplements that have NOT lived up to the hype: evening primrose oil and borage seed oil.
A number of studies have looked at treatment with evening primrose oil and borage seed oil. In one review, that combined the results of 27 different studies, it was found that treatment with either supplement failed to improve eczema symptoms, as compared to a comparison group that was given a placebo. Therefore, these are not recommended for the treatment of eczema. (It should be noted that most of the studies didn't mention whether typical eczema treatment was continued during this treatment, so we don't know for sure what the results would be in patients with eczema who aren't receiving any medical therapy.)
3. The last supplement category is one that sounds quite "natural", but may not be: Chinese Herbal Medicine (CHM).
The studies on Chinese herbal medicine were some of the most surprising for me. It turns out that CHM is not actually one specific herb or supplement or combination of herbs. Historically, CHM may be based on botanical substances, or it may actually include animal or mineral substances. Some of these preparations are based on a single Chinese medicinal herb or formula, while others are formulated as a customized formula for individual patients. A review of trials of CHM could NOT find any strong evidence that these preparations were helpful for eczema (either when applied to the skin or taken by mouth). While some of the individual studies reported beneficial effects, these were found by researchers to be based on low-quality evidence. While the ideal study would be one that compared standardized dosing and comparable herbs, that may not be possible with some forms of CHM, as some require customized formulas for individual patients. With so many unknowns and limited evidence for effectiveness (and even some rare but potentially severe side effects reported in studies), we don't recommend CHM at this time.