DIET'S ROLE IN FIGHTING VITILIGO HIGHLIGHTED IN NEW RESEARCH

By Hugo Francisco de Souza

In a recent review published in the Journal of Cosmetic Dermatology, researchers collated available literature exploring the impacts of diet and nutritional interventions against vitiligo. Their dataset comprised 14 publications from three online scientific databases. Review findings highlight that vitiligo, a relatively rare autoimmune skin disorder, potentially develops in response to increased somatic reactive oxygen species (ROS) concentrations. While some heavy metals (Cd, Hg, and Pb) have been implicated in the development of the condition, the impacts of trace minerals like Zn and Cu remain uncertain and conflicting.

Study: Exploring the impact of diet and nutrition on vitiligo: A systematic review of dietary factors and nutritional interventions. Image Credit: Master1305 / Shutterstock

In general, diets and nutritional interventions rich in ROS-depleting molecules (such as vitamin C, B12, and D, polyunsaturated fatty acids (PUFAs), and antioxidants are observed to trigger beneficial vitiligo outcomes and reduce the burden of metabolism, cellular deterioration, and oxidative stress brought about by ROS. While unlikely to replace pharmacological and phototherapy interventions against vitiligo, dietary interventions present an essential step forward in reducing our reliance on these potentially side-effect-inducing clinical interventions. However, large-scale clinical trials are required before these interventions can become commonplace.

What is vitiligo, and what do we know about its pathology?

Vitiligo is a rare autoimmune disorder characterized by the loss of skin pigmentation in patches or blotches, usually around the mouth, hair, and eyes. It is estimated to affect between 0.004% and 2.28% of the global population, and while phototherapy and pharmacological interventions can reduce symptom visibility, no cure for the condition hitherto exists. While the mechanisms underpinning the development and progression of vitiligo remain to be elucidated, the condition is assumed to be caused by a combination of hormonal and genetic factors, particularly those pertaining to cellular deterioration (of melanocytes), metabolic imbalances, and oxidative stress.

Heightened concentrations of reactive oxygen species (ROS) in tandem with reduced efficacy of the body's normal antioxidant mechanisms is assumed to substantially exacerbate the disease, with research finding substantial differences in the per-erythrocyte ROS production volumes of patients with (much higher) and without vitiligo. A growing body of literature presents that, while physically harmless, vitiligo is associated with more severe comorbidities, including alopecia areata, atopic dermatitis, and psoriasis.

As is the case in other chronic conditions characterized by altered ROS metabolism (some cancers and neurodegenerative conditions), diets are being explored for their potential antioxidant properties. Studies in various fields, including vitiligo research, support dietary interventions as natural, comparatively inexpensive, and generally side-effect-free alternatives to conventional clinical interventions (corticosteroids and calcineurin inhibitors), the latter of which are often costly and prone to side effects. Unfortunately, these studies are very recent and seemingly disconnected from each other, with a synthesis and holistic evaluation of the topic hitherto lacking.

About the study

In the present review (PROSPERO registration number CRD42023464740), researchers discuss up-to-date outcomes from studies and publications exploring the association between diet and vitiligo. Two independent reviewers collected papers from three online scientific repositories, namely PubMed, European PMC, and Google Scholar, using repository-optimized search strategies for publication acquisition and screening. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines were followed in the review's methodological design and presentation.

Of the 214 records originally found from keyword searches, 19 were found to be duplicates and were excluded. Title and abstract screening excluded 173 records, which was further curbed to the final publication set (n = 14) following full-text screening. The Rayyan platform was used to screen included publications. Elicit and PDF Gear platforms were subsequently used for data extraction, with critical variables including study identification details, methodological attributes, outcome measures, and a concise study summary.

"…studies lacking complete or accessible full-text articles were excluded to maintain the robustness of our ability to thoroughly assess and synthesize the findings."

The Critical Appraisal Skills Programme (CASP) tool was employed to assess the quality and risk of bias of included publications. Data synthesis comprised outcomes categorization and consolidation, followed by their visual representation as pie charts or bar diagrams.

Study findings

The present review highlights the critical role of ROS and the body's antioxidant mechanisms in the development and progression of vitiligo. ROS-producing heavy metals like cadmium (Cd), Mercury (Hg), and lead (Pb) are implicated as disease-causing substances. In contrast, the roles and impacts of micronutrients remain poorly understood, with studies presenting confounding and often contrasting results.

Vitamin supplements, especially C, D, and B12, have been hypothesized as potential anti-vitiligo interventions due to their high antioxidant efficacy.

"In a pilot study, the effectiveness of high-dose oral vitamin D supplementation on vitiligo repigmentation was investigated in 16 individuals with vitamin D deficiency vitiligo. Over half of the patients experienced 26%–75% repigmentation after consuming 35 000 IU daily.29 Supplementation is advised but dosing strategies aren't established."

Recently, researchers have begun exploring fatty acids such as saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) for their beneficial effects on vitiligo patients. PUFAs, particularly, have been shown to exert a strong immunosuppressive influence on the disease. Alpha Lipoic acid (ALA) alongside narrow band (NB) ultraviolet B (UVB) light has further been shown to reduce and even reverse vitiligo symptoms compared to a placebo.

While the present review highlights the present dearth of vitiligo-diet association research (only 14 publications met review inclusion criteria), substantial ongoing research will soon supplement our current knowledge in the field. While unlikely to dethrone corticosteroids and calcineurin inhibitors as the primary clinical interventions against vitiligo progression, studies have shown that the efficacies of both interventions are impressively bolstered by some dietary components, suggesting their future role as adjuncts.

"Further large-scale clinical trials are warranted to establish strong evidence and protocols, and might also help reduce the dependency on pharmacological methods, which come with their own adverse effect profiles."

2024-03-14T03:57:30Z dg43tfdfdgfd