The appearance of grey hair, or canities, is one of the most visible signs of aging and has been the subject of much speculation, especially after the radical change in former President Barack Obama's hair during his eight years in office. Scientifically, grey hairs lack melanin, the pigment derived from tyrosine that gives hair its color.
When melanocytes, the cells responsible for producing this pigment, stop functioning, the hair turns white. Dr. Manuel Ballesteros, a specialist dermatologist, points out that people of white and yellow races are usually affected earlier, between 30 and 40 years of age, while people of black race are affected later, starting their hair whitening after 45 years.
“"The loss of melanin, the loss of pigment in our hair, is a natural process, which like many problems in medicine is multifactorial."
Beyond genetics, which influences conditions like poliosis, factors such as a diet poor in antioxidants, smoking (which increases the probability up to four times), and autoimmune diseases like alopecia areata or pernicious anemia also accelerate canities.
The Harvard study delved into the role of physical or emotional stress, concluding that the activation of sympathetic nerves releases noradrenaline, causing a rapid and permanent loss of melanocyte stem cells in the hair follicle. To prevent this, experts recommend daily exercise, avoiding ultra-processed foods, and consuming foods rich in catalase, such as avocado or onion.
