Gray Hair Causes

Despite popular belief, gray hairs are not the result of wisdom nor are they caused by stress, at least not the kind of psychological stress you'd imagine. Rather, gray hairs are a natural part of aging in which damaged melanocytes produce less hair pigmentation than usual, resulting in transparent, white or gray-looking hair. Like wisdom, it happens when you are older, and like stress, it can be alarming, but it is a perfectly normal part of the human life cycle.

Natural Causes

Gray hair, regardless of the trigger, results from the loss of melanin, or melanocyte, production. According to a study published in the February 2009 edition of Federation of American Societies for Experimental Biology, researchers discovered that hydrogen peroxide, which is produced normally with hair cell development, accumulates over time due to the slowing of hydrogen peroxide breakdown. Consequently, as when we add the chemical to our hair, its buildup results in a bleaching from beneath the surface, causing the gray hair we see on our heads.

Genetics

In the case of genetics, scientists believe some humans inherit a premature maturation schedule, where the onset of gray hair occurs earlier than average. Based on research cited in the "ournal of Investigative Dermatology Symposium Proceedings, gray hair affects 18 percent of people by age 25 and 60 percent of people by age 35, occurring first in Caucasians, then Asians and finally Africans. It is not certain whether it comes from the mother's side, the father's side or both, but it appears that a family history of early graying can mean you may be affected by it as well.

Skin Disorders

Skin disorders such as tuberous sclerosis, Waardenburg syndrome and vitiligo, along with thyroid conditions such as Hashimoto's disease and Grave's disease, can reduce catalase levels in the body. Without normals levels of this enzyme, hydrogen peroxide accumulates and kills melanocytes, resulting in less hair pigmentation and ultimately gray hair.

Nutrient Deficiency

A nutrient deficiency of vitamin B12 can interrupt normal hair cell development, resulting in graying. Most foods provide more than an adequate supply of this nutrient, so grayness due to a nutrient deficiency is unlikely. However, people who follow a strict vegan diet may be missing out on a sufficient dosage. To fix this, look into starting a vitamin B12 supplement. If graying continues after a month, then assume it is not caused by a vitamin B12 deficiency.

Genotoxic Stress

Numerous scientific studies have reviewed the relationship between stress and gray hair. None of them have shown any significant results. Furthermore, as reported by the New York Times, baldness, heart-related mortality and facial wrinkles have no correlation with gray hair. However, a June 2009 study in Cell magazine discovered the possibility of genotoxic stress. That is, gene-related stress caused by radiation and UV light may deform hair cells and melanocytes, reducing hair pigmentation levels. For ethical reasons, the theory has only been tested on animals, but it seems promising for at least some causes of graying.