Graying of hair in young age "leukotrichia"

Leukotrichia (“Leuko” means white; “trichia” is from the Greek meaning hair or tail) in young individuals is a cosmetic health problem but can be indicative to many other ailments.
Before starting to jump on what to do, I must write some basics about the causes and general aspects of this condition. The most well established theory embraced by scientists for this condition is the Genetics of the individual. Hereditary factors play a major role as certain genes constitute this phenotype (what we see as the manifestation outwardly), displaying it for either certain set of conditions or even at a pre-programmed time. Simplifying it, for example, if an individual has this kind of hereditary graying of hair's pattern, on exposure to a peculiar sort of climate, physical or mental stress, malnutrition, hormonal imbalance secondary to any disease or infection, anemia specially Vitamin B12 deficiency pernicious anemia or Werner syndrome, pollution, thyroid disorder, Calcium deficiency (decreased bone density, mostly in post menopausal women) can be those triggering factors responsible for early grayish colouration of hair. If one's proximal relatives (father, mother, grand father, paternal and maternal relatives) had young aged grayish coloration, then it's most likely to have this condition precipitating earlier in life. Generally, when a person below 40 years of age has more than half of its hair gray, it's termed as "premature" graying of hair.
Melanocytes are the cells responsible for making a chemical named "Milanin", it's the same chemical or one can say "pigment" (color producing substance), which gives our body the unique blackish brown colour. When for any reason as mentioned above or even conditions like "Albinism" (genetic disorder), Vitiligo (auto immune disorder) etc. Melanin synthesis is hampered, the blackening of hair stops and it sprouts as grayish body from the Hair follicle. Melanocytes' Stimulating Hormone (MSH) is secreted by intermediate lobe of Pituitary gland, which is affected by length of night and day as well (presence or absence of natural light). That's why I stress upon disciplined diurnal lifestyle.
What to do?
The most convenient solution for this problem would be to Colour your hair, means dye your hair with any suitable and medically approved dying agent that are very easily available and widely accessible in market. Dietary supplements would only work if severe malnutrition is the triggering factor, such as pernicious anemia for B12 deficiency or even many a times Iron deficiency anemia (IDA) specially in young girls.
When people are paying for colouring hair, then why to be that sensitive on dying them! So, as long as possible, herbal dyes like Mehandi or similar solutions, mostly enumerated in Ayurvedic medicine or other conventional and traditional methods or one of the many competent dying cosmetic products available in market would do the trick. Remember, not to pluck the gray hair as many people report of engraving the problem in this way by having more of the hair being gray with the same gray hair sprouted again. To maintain Diurnal discipline (not to wake up much in night and lower the level of stress by Yoga or meditation, music etc.) being cheerful, sleeping at right time and getting well nourished with nutritious and balanced diet are basic precautions one must take in case of proximal relatives being affected with this problem.
Devashish Narayana Mishra