Hair color is determined by melanin, a pigment produced by melanocytes within hair follicles. There are two main types of melanin: eumelanin (brown, black) and pheomelanin (red, yellow), which combine in varying ratios to create natural hair color.
Melanocyte stem cells (MSCs) reside in hair follicles and replenish melanocytes throughout the hair growth cycle. With increasing age, oxidative stress, or systemic dysfunction, these stem cells can decline. When melanocytes cease to function, new hair strands grow without pigment, leading to gray or white hair. However, premature graying isn't always a sign of aging. In many cases, it signals various underlying health issues.
Vitamin B12 is essential for DNA synthesis, red blood cell formation, and nerve function. A deficiency in this vitamin can impair melanocyte activity, leading to premature graying. Besides hair changes, individuals with vitamin B12 deficiency may experience fatigue, anemia, and neurological disorders.
The thyroid gland regulates metabolism and hair follicle activity through thyroid hormones. Both hypothyroidism and hyperthyroidism can disrupt melanin production in hair follicles, resulting in premature graying, along with symptoms like thinning and dry hair.
Autoimmune diseases can directly affect melanocytes and hair follicles. Vitiligo destroys melanocytes in both the skin and hair, causing patchy depigmentation. Consequently, hair tends to turn gray or white.
Genetic disorders involving multiple organ systems can manifest as premature graying. Neurofibromatosis causes nerve tumors and is linked to early depigmentation. Tuberous sclerosis is a neurological condition characterized by benign tumors in the brain, kidneys, lungs, skin, heart, and other organs, with gray hair as a potential warning sign.
Iron, folic acid (vitamin B9), and zinc deficiencies can impair hair follicle activity. Copper deficiency disrupts tyrosinase, a key enzyme in melanin production. All these deficiencies can easily lead to changes in hair pigmentation, causing premature graying or whitening. Obesity, hypertension, and liver dysfunction accelerate oxidative stress, impairing melanocyte function.
Smoking increases the risk of lung cancer and heart disease. However, the long-term effects can extend beyond the heart and lungs, affecting hair. Smoking constricts blood vessels, potentially reducing blood flow to hair follicles and causing hair loss. Toxins in tobacco damage body parts, including hair follicles, leading to premature graying.
Stress is often linked to noticeable graying, especially in individuals under high pressure. Scientifically, stress impacts hair pigment through the sympathetic nervous system. Acute stress releases norepinephrine, causing melanocyte stem cells to overproduce, depleting their reserves and leaving regrown hair without pigment.
Maintaining a nutritious diet, managing stress, avoiding smoking, and undergoing regular health checkups can protect both hair pigment and long-term health. These practices may also reverse graying in some cases.
Bao Bao (Theo Healthline, Times of India)
