Study under review: Vitamin D and atopic dermatitis: A systematic review and meta-analysis
Atopic dermatitis (AD), also known as eczema, is a skin condition that causes dry, itchy red skin. Scratching can result in inflammation and injury to the epidermis, the top-most layer of the skin. The prevalence of this condition has been increasing in both children and adults over the past several decades. It can affect up to 20% of children, though symptoms usually resolve for most prior to adulthood. One trial showed that people who get more sun exposure have a lower incidence of AD, and that symptoms are generally more severe in winter when sunlight exposure is lower, although most people tend to have an increase in dry itchy skin during the winter months when the skin is exposed to colder and drier air.
There has been some evidence to show that a higher intake of certain vitamins, including vitamins D and E, may improve the symptoms of AD. Several different mechanisms of action have been suggested, some of which are shown in Figure 1. One is that vitamin D can increase the production of antibacterial peptides and barrier formation molecules on the surface of the skin, which strengthens and prevents infection of the skin surface. There is also evidence that vitamin D supports the production of a number of immune system molecules related to the reduction of inflammation.
While several individual studies have been completed in various populations to assess the effects of vitamin D supplementation on AD, the results of studies have been somewhat inconsistent, and no meta-analysis to date has been conducted to evaluate the overall trend of these studies. The authors set out to assess the relevant literature on AD and vitamin D, and conduct a meta-analysis of clinical trials on this topic.
Atopic dermatitis, or eczema, is a skin disease that has been increasing in prevalence worldwide. Both oral intake of vitamin D and increased sun exposure have been associated with improvements in the symptoms of AD.
Other Articles in Issue #20 (June 2016)
Interview: Rick Miller, MSc, RD
Most cows provide milk that contains at least some of a protein called A1 betacasein. Rick explains the difference between A1 and A2 beta-casein, and what benefits may be associated with A2 milk.
Mamas, don’t let your babies grow up to be gluten intolerant
We’ve previously covered peanut introduction in infants, and next up is gluten introduction. These researchers analyzed the changing literature looking at celiac disease risk when gluten is introduced at different times.
Do probiotics alter gut microbiome composition?
Probiotic ads tout the number of live bacteria they contain, typically numbering in the billions. But our guts already contain trillions of bacteria. Do probiotics actually change the makeup of our microbiomes?
Fattening up breakfast for weight loss
Calories are the most important weight loss factor, but not the only one. It turns out that the type of fats you eat may impact your appetite, and this trial tested two fats (CLA and MCT) for that purpose.
Dead, yet active probiotics?
We know that the gut microbiome can play a major role in a variety of conditions, but the specifics are still being teased out. This study tested the effect of one particular strain called Pediococcus pentosaceus LP28, in a heatkilled formulation.
Carnosine for blood sugar control
If you join together the amino acids l-histadine and beta-alanine, you get the dipeptide called carnosine. Carnosine may have a variety of benefits, and this trial tested carnosine’s specific effect on insulin dynamics.
Coenzyme Q10 and chronic fatigue syndrome
Chronic fatigue syndrome is a life-changing condition without many effective treatments. Could daily supplementation with coenzyme Q10 be a simple way to improve symptoms?
Can arachidonic acid work as a bodybuilding supplement?
There isn’t nearly as much research on potential benefits of omega-6 fatty acids as there is on omega-3s. This study looked at the effect of the omega-6 known as arachidonic acid on resistance exercise