The role of diet in combating vitiligo highlighted in new research

In a recent review published in the Journal of Cosmetic Dermatology, researchers collected available literature examining the impact of diet and nutrition interventions against vitiligo. Their dataset consisted of 14 publications from three online scientific databases. Research findings highlight that vitiligo, a relatively rare autoimmune skin condition, may develop in response to elevated levels of somatic reactive oxygen species (ROS). Although some heavy metals (Cd, Hg and Pb) have been implicated in the development of the condition, the effects of trace minerals such as Zn and Cu remain uncertain and contradictory.

Study: Investigating the impact of diet and nutrition on vitiligo: a systematic review of dietary factors and nutritional interventions. Image credits: Master1305 / Shutterstock

In general, diets and nutritional interventions rich in ROS-depleting molecules (such as vitamins C, B12, and D, polyunsaturated fatty acids (PUFAs), and antioxidants) are observed to induce beneficial vitiligo outcomes and reduce the burden of metabolism, cellular decline, and oxidative stress caused by ROS. Although unlikely to replace pharmacological and phototherapy interventions against vitiligo, dietary interventions represent an essential step forward in reducing our dependence on these potentially side-effect-causing 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 disease characterized by the loss of skin pigmentation in patches or spots, usually around the mouth, hair and eyes. It is estimated that between 0.004% and 2.28% of the world’s population is affected, and although phototherapy and pharmacological interventions can reduce the appearance of symptoms, there is as yet no cure for the condition. Although the mechanisms underlying the development and progression of vitiligo remain to be elucidated, the condition is believed to be caused by a combination of hormonal and genetic factors, particularly those related to cellular decline (of melanocytes), metabolic imbalances and oxidative stress.

Elevated concentrations of reactive oxygen species (ROS) combined with reduced efficacy of the body’s normal antioxidant mechanisms are thought to significantly worsen the disease, with research showing significant differences in patients’ per-erythrocyte ROS production volumes with (much higher) and without vitiligo. A growing body of literature suggests that vitiligo, while physically harmless, is associated with more serious comorbidities, including alopecia areata, atopic dermatitis, and psoriasis.

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

About the study

In the current review (PROSPERO registration number CRD42023464740), researchers discuss current results from studies and publications examining the association between diet and vitiligo. Two independent reviewers collected articles from three online scientific repositories, namely PubMed, European PMC and Google Scholar, using repository-optimized search strategies for acquiring and screening publications. The methodological design and presentation of the review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines.

Of the 214 records originally found in keyword searches, 19 were found to be duplicates and were excluded. Title and abstract screening excluded 173 records, which was further limited to the final publication set (n = 14) after full-text screening. The Rayyan platform was used to screen recorded publications. Elicit and PDF Gear platforms were then used for data extraction, with critical variables including study identification details, methodological features, 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 review and synthesize the findings.”

The Critical Appraisal Skills Program (CASP) instrument was used to assess the quality and risk of bias of included publications. Data synthesis involved the categorization and consolidation of outcomes, followed by their visual representation as pie charts or bar charts.

Findings of the study

The current review highlights the crucial role of ROS and the body’s antioxidant mechanisms in the development and progression of vitiligo. ROS-producing heavy metals such as cadmium (Cd), mercury (Hg) and lead (Pb) have been implicated as pathogens. In contrast, the roles and effects of micronutrients remain poorly understood, with studies yielding confusing and often contradictory results.

Vitamin supplements, especially C, D and B12, are believed to be potential anti-vitiligo interventions due to their high antioxidant activity.

“In a pilot study, the effectiveness of high-dose oral vitamin D supplementation on the repigmentation of vitiligo was examined in 16 individuals with vitamin D deficiency vitiligo. More than half of the patients experienced 26%-75% repigmentation after daily consumption of 35,000 IU.29 Supplementation is advised, but no dosing strategies have been established.”

Recently, researchers have begun investigating fatty acids such as saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) for their beneficial effects on vitiligo patients. PUFAs in particular have been shown to exert a strong immunosuppressive influence on the disease. Alpha lipoic acid (ALA) and narrowband (NB) ultraviolet B (UVB) light have further been shown to reduce and even reverse symptoms of vitiligo compared to a placebo.

Although the current review highlights the current lack of research on associations between vitiligo and diet (only 14 publications met the inclusion criteria for the review), substantial ongoing research will soon complement our current knowledge in this area. Although it is unlikely that corticosteroids and calcineurin inhibitors will be dethroned as the primary clinical interventions against the progression of vitiligo, studies have shown that the efficacy of both interventions is impressively enhanced by a number of dietary components, suggesting their future role as adjuncts.

“Further large-scale clinical trials are warranted to establish strong evidence and protocols, and may also help reduce reliance on pharmacological methods, which have their own side effect profiles.”