Such factors can include, nutritional deficiencies, especially the deficiency of vitamin B12, zinc, iodine, and iron, prolonged periods of illness or stress, smoking, thyroid problems, and skin disorders, like tuberous sclerosis and vitiligo. Many times, an unhealthy diet and wrong eating habits can also cause premature graying. The excessive consumption of fried, oily, spicy, and acidic foods, and coffee and other caffeinated beverages may be associated with this condition.