I’m so excited to share this incredibly relevant and high yield conversation with Dr. Peter Lio. If you are wondering if you should avoid gluten in your diet and/or skincare, pondering which petroleum alternatives are best for dry skin, or how ingredients like honey and oatmeal affect skin health and our skin microbiome, this is a must read!
[More about Dr. Lio: he is a Clinical Assistant Professor of Dermatology & Pediatrics at Northwestern University Feinberg School of Medicine. He received his medical degree from Harvard Medical School, completed his internship in Pediatrics at Boston Children’s Hospital, and his Dermatology training at Harvard. While at Harvard, he received formal training in acupuncture. He is a world renowned expert in eczema and alternative medicine. He is also the co-editor of what I think will become a bible for dermatologists who are interested in a holistic and comprehensive approach to the skin, Integrative Dermatology: Practical Applications in Acne and Rosacea. I’ve already pre-ordered my copy and can’t wait to get it in my hands!]
Q & A:
Dr. Bowe: Many people are trying to avoid gluten in their diets as well as their skincare. We often see “gluten free” on food labels as well as skincare labels. What is your take on whether people should avoid gluten in foods/how do you know if you should avoid it?
Dr. Lio: Gluten has been soundly vilified in the past few years, but I’m not sure it’s totally deserving of all of the hate. Clearly for people that have celiac disease it is essential to totally avoid it; outside of this select group, things get a little more confusing. My feeling is that some people really do have a sensitivity to gluten that doesn’t necessarily show up on testing, and for others it may be that simple carbohydrates and refined sugars in foods are causing their issues, but that they are so closely associated with gluten in a modern diet that people really do improve by throwing out the baby with the bathwater, so to speak. I do think that diets that avoid gluten (and grains in general) tend to be healthier since they usually focus more on greens and vegetables–it is hard to argue with that! However, as a fan of baking breads and a lover of pizza, I’d like to think that gluten-containing foods can be healthy and well-tolerated for many, especially when prepared in a wholesome way and eaten in moderation.
Dr. Bowe: How important do you think it is to avoid gluten in skincare for most people/how do you know if you should avoid it?
Dr. Lio: In skincare, I think it is even more confusing. Perhaps even for those with celiac disease, my sense is that as a large protein there is probably little or no absorption of gluten through the skin, so I’m not sure making a “gluten-free” claim has much real meaning outside of “sounding” healthier. To be honest, though, the vast majority of skin care products that I am aware of have never had gluten in the first place, so it’s a little disingenuous, sort of like advertising “gluten free apples.”
Dr. Bowe: Oatmeal has been shown to be very beneficial for dry, itchy, eczema prone skin. Can a moisturizer containing oatmeal be used in someone who believes they are sensitive to gluten?
Dr. Lio: I think the answer is yes for most patients. While there are patients with true allergy to oat and they must totally avoid oatmeal-containing products, it turns out that pure oats do not contain gluten at all, but during harvesting and transportation, sometimes gluten can be introduced. Because of this, many companies have switched to using certified gluten-free oats for skin products, and I think this is a good thing since oatmeal can be helpful in a variety of products, especially as you say, for dry and itch skin.
Dr. Bowe: We’re well aware that natural is NOT always better, and not all natural ingredients are inherently safe for the skin. However, from what I have read and experience with my patients, honey has been reported to have a number of benefits and appears to be very safe for use on skin. What are your thoughts about the use of honey in skincare and in your diet when it comes to skin benefits?
Honey in skincare:
Honey is pretty amazing stuff! There is reasonably good evidence for using honey in wound healing and burn treatment, and even some evidence for treating acne and rosacea. It has some powerful antibacterial properties and is very soothing for the skin. However, all honeys are not the same. Certain honeys such as Manuka and Kanuka have robust literature on their healing properties, and Manuka even has a special rating called a UMF (Unique Manuka Factor) that helps quantify its quality. As you might imagine, the higher UMF honeys (greater than 20, for example) can be prohibitively expensive. Additionally, honey is tough to work with: it’s sticky and thick, making it difficult to leave on the skin during the day or even overnight, so that can be limiting as well.
Honey in diet:
I think that having some honey in the diet can be healthy. Honey has a lower glycemic index than sugar, but still contains sugars. I have seen evidence that honey is likely better than agave nectar as a sugar alternative, especially because of its other health benefits. However, it is something to use sparingly, I think, since sugary foods seem to fuel inflammation for a lot of my patients.
Dr. Bowe: Honey, especially manuka honey, is known for its antibacterial properties. Now that we know how critical a healthy, diverse skin microbiome is, how do you reconcile use of an antibacterial ingredient in a disease where bacterial diversity and health is so critical?
Dr. Lio: I think this is the kind of question that we are really struggling with right now. It seems that our over-simplified understanding of “bacteria” as a monolithic pathogen has led to using sledge-hammers like antibiotics for lots of conditions without really taking the complexity of the microbiome into consideration. My sense is that in disease there is imbalance. Sometimes, even shaking things up in a very inelegant way can allow for the balance to return. Many are now too young to remember this, but when we were growing up, we had an old Cathode Ray Tube television. Sometimes the picture would blink and flash… and we’d give it a firm whack on the side and voila–it would work again! This to me is an analogy of why relatively crude approaches seem to help sometimes, especially when we take into account more natural products that have subtleties that we cannot always fully appreciate.
Dr. Bowe: While I don’t love coconut oil for acne prone areas such as the face, chest and back, I do find that it can be very hydrating and calming in my patients who are not acne prone, but do suffer from very dry skin. Coconut oil is also known for its antibacterial properties. How do you address concerns that ingredient like coconut oil might be damaging our microbiome, or decrease diversity of our microbiome?
Dr. Lio: I would say that, as we discussed with honey, natural antimicrobials tend to be much more subtle and nuanced than medical-grade antiseptics, disinfectants, and antibiotics. Coconut oil does seem to be antimicrobial (perhaps due to the monolaurin), but also has supportive elements that can strengthen the skin barrier and, in turn, the microbiome, such as medium-chain fatty acids. I think we have a lot more to learn about this, but it does seem to be gentle enough to use in both dry, irritated skin but also on healthy skin, and that suggests that it is not knocking things out of balance for most people. In atopic dermatitis we often see staphylococcus aureus bacteria start to dominate and, accordingly, diversity of the microbiome suffers. Application of coconut oil in this scenario led to a 95% decrease in staphylococcus aureus, suggesting that diversity was restored.* But we really do need more research here.
*Ref: Verallo-Rowell VM, Dillague KM, Syah-Tjundawan BS. Novel antibacterial and emollient effects of coconut and virgin olive oils in adult atopic dermatitis. Dermatitis. 2008 Nov 1;19(6):308-15.
Dr. Bowe: Skin hydration is so important in people who suffer from eczema. What are your favorite ingredients to look for in moisturizers, especially if someone is looking for petroleum-free ingredients. One of my favorites is sunflower seed oil. Curious what you think about that ingredient or any others you like to recommend for your patients who suffer from eczema?
Dr. Lio: I am a big fan of sunflower seed oil as well—there is evidence that it calms inflammation, helps heal the skin barrier, and even stimulates the production of natural ceramide fats in the skin, all of which are fantastic for patients with eczema.
We mentioned coconut oil above for its ability to decrease staph bacteria in eczema, but it turns out that it is an excellent moisturizer as well, and outperformed a petroleum product (mineral oil) in a head-to-head study.*
I’ve been very interested in a plant called Cardiospermum halicacabum which has some very interesting anti-inflammatory properties** and I have worked with a small company to get a very natural moisturizer that features this ingredient as well.
*Ref: Agero AL, Verallo-Rowell VM. A randomized double-blind controlled trial comparing extra virgin coconut oil with mineral oil as a moisturizer for mild to moderate xerosis. Dermatitis. 2004 Sep 1;15(3):109-16.
**Ref: Fai D, Fai C, Di Vito M, Martini C, Zilio G, De Togni H. Cardiospermum halicacabum in atopic dermatitis: clinical evidence based on phytotherapic approach. Dermatologic Therapy. 2020 Nov 10:e14519.
Dr. Bowe: Are any salts, minerals or vitamins especially helpful when applied topically?
Dr. Lio: Topical vitamin B12 seems to help with eczema. I actually developed a version of this after reading a very compelling study* but not being able to find a commercial version available, and that has been helpful for some of my patients. We call it “Pink Magic” because the B12 powder is dark crimson and when mixed with the shea butter base, it makes a lovely pink color!
Zinc oxide, best known as the base of many diaper pastes, is incredibly gentle and soothing for damaged or open skin. It is probably underutilized because it is so thick and pasty, but I often use it as part of cooling wraps for patients with open areas of skin, and this wrap (known as the Unna Boot) has tremendous healing properties.
*Ref: Stücker M, Pieck C, Stoerb C, Niedner R, Hartung J, Altmeyer P. Topical vitamin B12—a new therapeutic approach in atopic dermatitis—evaluation of efficacy and tolerability in a randomized placebo‐controlled multicentre clinical trial. British Journal of Dermatology. 2004 May;150(5):977-83.
Dr. Bowe: Any salts (electrolyes), minerals or vitamins you suggest getting in your diet to improve skin hydration or skin health?
Dr. Lio: I am an avid proponent of vitamin D supplementation for all my patients with atopic dermatitis. There is a little bit of controversy around this, but I truly think that there is a group for whom it makes a big difference. The problem is, I can’t predict who will be in that group! So I think it’s reasonable (especially here in cold, gray Chicago) to have folks supplement with vitamin D—I certainly do so myself.
It’s not quite a vitamin, but probiotics also have a fascinating body of evidence in atopic dermatitis. Like vitamin D, I think there really are some patients who do better on them, although we are in the early days of understanding which strains, the dosage, the frequency, etc. Right now, I like a probiotic mix that contains Lactobacillus paracasei and Lactobacillus fermentum as these have the some of the best evidence in atopic dermatitis.*
*Ref: Wang IJ, Wang JY. Children with atopic dermatitis show clinical improvement after Lactobacillus exposure. Clinical & Experimental Allergy. 2015 Apr;45(4):779-87.
Dr. Bowe: What nutritional advice do you give patients suffering from very dry skin who wish to hydrate from the inside out?
Dr. Lio: There is an interesting literature about an amino acid supplement L-histidine (not to be confused with “histamine”). I do recommend this for some patients as it seems to be able to help restore the skin barrier and seems very safe and inexpensive. The dose for adults is 4 grams per day, and it is widely available in health food stores as a powder.
Dr. Bowe: Fragrance, especially natural fragrances like essential oils, is such a confusing topic. What do you tell patients when it comes to fragrance in skincare: what to look for vs what to avoid?
Dr. Lio: Here I am pretty firm: I prefer no fragrances whatsoever for my sensitive skin patients and especially for those with eczema/atopic dermatitis. The reason is that even potentially helpful natural fragrances, especially in these more sensitive folks, can become allergens over time, sensitizing them to these products. Ideally, we want products that have been designed for and tested in atopic dermatitis patients. We want as few ingredients as possible, and there is a long list of things we specifically want to avoid. A great resource can be found at The National Eczema Association website.
Disclosure: I’m a board member and a Scientific Advisory Committee member, but I only donate to the NEA I do not make any money from them. They are a non-profit organization dedicated to improving the lives of patients with eczema.
Dr. Bowe: Vit E: are there skin benefits to using it topically? What about via supplementation?
Dr. Lio: To my knowledge, there is no good data about topical vitamin E in eczema, but there was a neat study showing that 400 IU of vitamin E daily improved eczema symptoms and signs better than a placebo at 4 months.* This is a very reasonable supplement to add for those with eczema, I think.
*Ref: Jaffary F, Faghihi G, Mokhtarian A, Hosseini SM. Effects of oral vitamin E on treatment of atopic dermatitis: A randomized controlled trial. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences. 2015 Nov;20(11):1053.
Dr. Bowe: Some prebiotics, like inulin, are made of sugars linked together? We know sugar is not good in your diet, but could sugar on the skin be a good thing for your microbiome?
Dr. Lio: Yes, I think that the concept of prebiotics and synbiotics (prebiotics + probiotics) are very compelling topically applied to the skin. In fact, I’m currently an investigator for a new topical probiotic spray that seems very promising. I think that sugars on the skin have a very different effect than those in the diet since they can directly feed the bacteria there and are likely not absorbed into the body. This question has actually come up because of “sugar scrubs”: I had a patient with diabetes who wanted to try them, but was concerned. So long as there are not actual cuts or abrasions, the sugar is not absorbed and it is safe.
I hope you found this discussion as eye opening as I did! For more of Peter Lio’s tips and expertise, be sure to follow him on:
And on Twitter too: @ChiEczema
Hope you enjoyed this exciting and truly informative Q & A.