Assessing the relationship between dietary factors and hair health: A systematic review

Background Specific foods and nutrients have a significant importance in maintaining healthy hair, which is a crucial aspect of an individual's identity and self-esteem. Aim To identify, through a literature review, the association between the consumption of specific foods and/or nutrients and the health of the hair. Methods This review followed the PRISMA guidelines and was registered on the PROSPERO platform (registration number: CRD42024527250). The databases Medline (PubMed), Web of Science and Scopus were consulted between March and June 2024. The following inclusion criteria were considered: individuals aged ≥3 years old; the consumption/intake of specific foods/nutrients; and articles written in English and Portuguese. The search expression combined terms related to ‘diet’, ‘nutrition’ and ‘hair health’ ( n = 1287 articles), where language filters and duplicate removal were applied. Results The analysis of 17 studies involved 61332 participants, predominantly women (97%). Vitamin D stood out as the most studied nutrient (five studies), while alopecia and hair loss were the most studied hair health parameters (eight and five studies, respectively). Higher levels of vitamin D and iron were inversely related to alopecia. Conversely, a higher intake of alcoholic and sugary beverages was found to be positively correlated with hair loss. Conclusion Diet and nutrition play a crucial role in hair health, particularly vitamin D and iron supplementation, while limiting alcohol and soft drinks may be beneficial. Further research is needed to confirm these findings.