Nutritional Disorders of the Hair and Their Management

Abstract

The quantity and quality of hair are closely related to the nutritional state of an individual. In instances of protein and calorie malnutrition, deficiency of essential amino acids, of trace elements, and of vitamins, hair growth and pigmentation may be perturbed. The effects of nutrition on hair growth and pigmentation have been recognized from observations in rare inborn errors of metabolism of copper (Menkes kinky hair syndrome), zinc (acrodermatitis enteropathica), biotin (biotinidase and holocarboxylase synthetase deficiency), and amino acids (homocystinuria, Hartnup disease, phenylketonuria, and methionine malabsorption syndrome), in specific acquired deficiency disorders, and from the respective supplementation studies. All vitamins were identified by 1948, ushering in a half century of discovery focused on single-nutrient-deficiency diseases. The first half of the twentieth century witnessed the identification and synthesis of many of the known essential vitamins and minerals and their use to prevent and treat nutritional deficiency-related diseases, specifically protein-calorie malnutrition, deficiencies of biotin, vitamin C, vitamin B12, niacin, essential fatty acids, iron, zinc, copper, selenium, and vitamin D. Accelerating economic development and modernization of agricultural, food processing, and food formulation techniques continued to reduce single-nutrient-deficiency diseases globally. In response, nutrition science shifted to the research on the role of nutrition in more complex conditions, such as gluten sensitivity, obesity, bariatric surgery, anorexia and bulimia, alcoholism, aging, and the oncologic patient. Additional complexity may arise in nutritional recommendations for general well-being versus treatment of specific conditions. Recognition of complexity is a key lesson of the past. Initial observations lead to reasonable, simplified theories that achieve certain practical benefits, which are then inevitably advanced by new knowledge and recognition of ever-increasing complexity.