Diet and hair loss: effects of nutrient deficiency and supplement use

The 2017 document reviews the relationship between nutrient deficiencies and hair loss, as well as the impact of supplement use on hair growth. It finds that deficiencies in nutrients like iron, zinc, fatty acids, selenium, and vitamin D can cause hair loss, but there is limited evidence supporting supplementation in individuals without deficiencies. Over-supplementation can sometimes worsen hair loss or cause toxicity. A small study of 21 volunteers showed that vitamin E supplementation increased hair count, but high doses can be harmful. Biotin deficiency can cause hair loss, but supplementation has not been proven effective without a deficiency. Protein malnutrition and oxidative stress are also linked to hair loss, but the role of amino acids, proteins, and antioxidants needs more research. The document concludes that while correcting nutrient deficiencies is important, the efficacy of supplementation in the absence of deficiency is unclear, and physicians should counsel patients on the potential risks and lack of substantial evidence for using supplements to treat hair loss.