Alexandra R. Vaughn

Effects of Turmeric (Curcuma longa) on Skin Health: A Systematic Review of the Clinical Evidence

Turmeric (Curcuma longa), a commonly used spice throughout the world, has been shown to exhibit antiinflammatory, antimicrobial, antioxidant, and anti‐neoplastic properties. Growing evidence shows that an active component of turmeric, curcumin, may be used medically to treat a variety of dermatologic diseases. This systematic review was conducted to examine the evidence for the use of both topical and ingested turmeric/curcumin to modulate skin health and function. The PubMed and Embase databases were systematically searched for clinical studies involving humans that examined the relationship between products containing turmeric, curcumin, and skin health. A total of 234 articles were uncovered, and a total of 18 studies met inclusion criteria. Nine studies evaluated the effects of ingestion, eight studies evaluated the effects of topical, and one study evaluated the effects of both ingested and topical application of turmeric/curcumin. Skin conditions examined include acne, alopecia, atopic dermatitis, facial photoaging, oral lichen planus, pruritus, psoriasis, radiodermatitis, and vitiligo. Ten studies noted statistically significant improvement in skin disease severity in the turmeric/curcumin treatment groups compared with control groups. Overall, there is early evidence that turmeric/curcumin products and supplements, both oral and topical, may provide therapeutic benefits for skin health. However, currently published studies are limited and further studies will be essential to better evaluate efficacy and the mechanisms involved. Copyright

Natural Oils for Skin-Barrier Repair: Ancient Compounds Now Backed by Modern Science

Natural plant oils are commonly used as topical therapy worldwide. They are usually easily accessible and are relatively inexpensive options for skin care. Many natural oils possess specific compounds with antimicrobial, antioxidant, anti-inflammatory, and anti-itch properties, making them attractive alternative and complementary treatments for xerotic and inflammatory dermatoses associated with skin-barrier disruption. Unique characteristics of various oils are important when considering their use for topical skin care. Differing ratios of essential fatty acids are major determinants of the barrier repair benefits of natural oils. Oils with a higher linoleic acid to oleic acid ratio have better barrier repair potential, whereas oils with higher amounts of irritating oleic acid may be detrimental to skin-barrier function. Various extraction methods for oils exist, including cold pressing to make unrefined oils, heat and chemical distillation to make essential oils, and the addition of various chemicals to simulate a specific scent to make fragranced oils. The method of oil processing and refinement is an important component of selecting oil for skin care, and cold pressing is the preferred method of oil extraction as the heat- and chemical-free process preserves beneficial lipids and limits irritating byproducts. This review summarizes evidence on utility of natural plant-based oils in dermatology, particularly in repairing the natural skin-barrier function, with the focus on natural oils, including Olea europaea (olive oil), Helianthus annus (sunflower seed oil), Cocos nucifera (coconut oil), Simmondsia chinesis (jojoba oil), Avena sativa (oat oil), and Argania spinosa (argan oil).

Effects of Fermented Dairy Products on Skin: A Systematic Review

OBJECTIVE Fermented dairy products, such as yogurt, have been proposed as a natural source of probiotics to promote intestinal health. Growing evidence shows that modulation of the gastrointestinal tract microbiota can modulate skin disease as well. This systematic review was conducted to examine the evidence for the use of ingested fermented dairy products to modulate skin health and function. We also sought to review the effects of the topical application of dairy products. DESIGN The PubMed and Embase databases were systematically searched for clinical studies involving humans only that examined the relationship between fermented dairy products and skin health. RESULTS A total of 312 articles were found and a total of 4 studies met inclusion criteria. Three studies evaluated the effects of ingestion, while one evaluated the effects of topical application. All studies noted improvement with the use of fermented dairy. CONCLUSIONS Overall, there is early and limited evidence that fermented dairy products, used both topically and orally, may provide benefits for skin health. However, existing studies are limited and further studies will be important to better assess efficacy and the mechanisms involved.

Circadian rhythm in atopic dermatitis—Pathophysiology and implications for chronotherapy

Circadian rhythm is a biological clock that controls a wide range of physiological functions throughout the body, including various skin functions. A 24‐h diurnal cycle, governed by an endogenous clock in the brain, largely controls cutaneous diurnal rhythm, which external factors, including temperature, humidity, diet, and stress, also modulate locally. Circadian rhythm influences cutaneous blood flow and properties of skin barrier function, such as transepidermal water loss and capacitance, and has important implications in atopic dermatitis (AD). This review explores how aberrations in circadian rhythm may play a role in the pathogenesis of AD and proposes implementation of chronotherapy to improve treatment outcomes in patients with AD.

Sweat mechanisms and dysfunctions in atopic dermatitis

Skin barrier dysfunction is inherent to atopic dermatitis (AD), causing dryness, irritation, and increased permeability to irritants, allergens and pathogens. Eccrine sweat functions as part of the skins protective barrier. Variations in sweat responses have been observed in patients with AD, and altered sweat composition and dynamics are under-recognized as important factors in the disease cycle. This review discusses the role that sweat plays in the pathogenesis of AD, examines evidence on abnormal sweat composition, secretion, and neuro-immune responses to sweat in atopic skin, and highlights the value of sweat management.

Multi-Center Randomized Clinical Study of The Effects of Natural Oils on Xerosis and Skin Barrier Properties

Objective : To compare the effect of natural oils and white petrolatum on skin barrier function in patients with xerosis. Design, Setting, and Participants : Randomized, open label, comparison pilot study (NCT03093597). Interventions : Participants were randomized to apply 1 of 4 moisturizers to assigned treatment areas twice daily for 2 weeks. Clinical dry skin score, stratum corneum hydration, and transepidermal water loss (TEWL) were assessed at baseline, 1 week, and 2 weeks. Results : Thirty-two participants completed the study. Neither TEWL nor hydration were statistically different among the moisturizers at each visit. All four moisturizers led to significant initial increase in TEWL at week 1 (p < 0.05) with an associated increase in hydration for coconut oil, jojoba oil, and white petrolatum. All four moisturizers led to significant increase in hydration by week 2 (p < 0.01). The preferred moisturizers were almond oil and coconut oil, which were most “liked” by 38% and 31% of the participants, respectively. The least preferred moisturizer was white petrolatum. Conclusions : Almond oil, jojoba oil, and coconut oil significantly increased hydration after 2 weeks, and are as effective as white petrolatum as daily moisturizers for xerosis. The participants preferred natural oils to white petrolatum, implying that these moisturizer options may improve patient compliance.

Effects of Turmeric and Curcumin Dietary Supplementation on Human Gut Microbiota: A Double-Blind, Randomized, Placebo-Controlled Pilot Study:

Background. Curcuma longa (common name: turmeric) and one of its biologically active constituents, curcumin, have received increased clinical attention. Insufficient data exist on the effects of curcumin and turmeric on the gut microbiota and such studies in humans are lacking. Methods. Turmeric tablets with extract of piperine (Bioperine) (n = 6), curcumin with Bioperine tablets (n = 5), or placebo tablets (n = 3) were provided to healthy human subjects and subsequent changes in the gut microbiota were determined by 16S rDNA sequencing. Results. The number of taxa detected ranged from 172 to 325 bacterial species. The placebo group displayed an overall reduction in species by 15%, whereas turmeric-treated subjects displayed a modest 7% increase in observed species posttreatment. Subjects taking curcumin displayed an average increase of 69% in detected species. The gut microbiota response to treatment was highly personalized, thus leading to responders and nonresponders displaying response concordance. These “responsive” subjects defined a signature involving uniform increases in most Clostridium spp., Bacteroides spp., Citrobacter spp., Cronobacter spp., Enterobacter spp., Enterococcus spp., Klebsiella spp., Parabacteroides spp., and Pseudomonas spp. Common to these subjects was the reduced relative abundance of several Blautia spp. and most Ruminococcus spp. Conclusions. All participants’ microbiota displayed significant variation over time and individualized response to treatment. Among the responsive participants, both turmeric and curcumin altered the gut microbiota in a highly similar manner, suggesting that curcumin may drive the majority of observed changes observed in turmeric-treated subjects.

Topical micronutrients in atopic dermatitis-An evidence-based review

The role of dietary factors is an important and controversial topic in the pathogenesis of atopic dermatitis (AD). Despite the preponderance of consumer products utilizing oral micronutrients supplementation for relief AD symptoms, less attention has been paid on the utility of topical micronutrients, specifically for individuals with AD. We review evidence on topical formulations of vitamins (A, B, C, D, and E) and trace minerals (magnesium, manganese, zinc, and iodine) for treatment of AD. While topical B, C, and E formulations appear to provide some benefit to AD individuals, topical vitamin A has no utility, and topical vitamin D may exacerbate symptoms. Magnesium, zinc, and iodine all appear to improve AD through anti‐inflammatory and anti‐microbial effects, though future studies must evaluate their use as monotherapy. The exposition of the effects that topical micronutrients have on AD offers an adjuvant treatment modality for this common inflammatory dermatosis.

A Concise Review of the Conflicting Roles of Dopamine-1 versus Dopamine-2 Receptors in Wound Healing

Catecholamines play an important regulatory role in cutaneous wound healing. The exact role of dopamine in human epidermis has yet to be fully elucidated. Current published evidence describes its differential effects on two separate families of G protein coupled receptors: D1-like and D2-like dopamine receptors. Dopamine may enhance angiogenesis and wound healing through its action on dopamine D1 receptors, while impairing wound healing when activating D2 receptors. This review summarizes the evidence for the role of dopamine in wound healing and describes potential mechanisms behind its action on D1 versus D2-like receptors in the skin.

Paternal vs. Maternal Factors in Childhood Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disease that chronically affects children and adults worldwide. Environmental exposures, heritable factors, immune dysregulation, and skin barrier malfunction all contribute to the multifactorial nature of AD. It is known that maternal and paternal influences are important predictors for the risk of AD in offspring. This review examines and compares the evidence and mechanisms behind specific maternal and paternal factors that may contribute to the pathogenesis of AD.