White hair. To get back my black hair?

Hi thanks for your query. Firstly there are lot of reasons for getting gradual pre  mature white hair or falling of hair. 1. Genetically happened or genetic factors ' 2. Gastric disorders since long years. Or G.I disorders..3. Any acute or chronic disorders like meningitis'cholera, typhoid.... etc affected by pathogens bacteria, virus etc. 4. Infection due to water,air,environmental.. 5.calcium shortage..or crisis 6. external oils,shampoo, 7.unhygienic ,lack of cleanliness etc..Now u can cross check where is the problem from your side? I suggest take calcium rich foods .plant protein s, plenty of green vegetables, greens,all types of fruits,, papayas, gourd family veges. Turmeric raw,fresh water sleep 7 hours, no stress at all. Disciplined life styles timely ..mild exercise, early morning rise.