The condition of your hair is a reflection of your body's general health. Its condition changes for the worse with stress, nutritional deficiencies, hormone shifts, and environmental factors. The real culprit when it comes to dandruff may be a fat-eating, yeast-like fungus called malassezia, formerly known as pityrosporum.
Malassezia lives on the scalps of most healthy adults without causing problems. But sometimes it grows out of control, feeding on the oils secreted by your hair follicles and causing irritation that leads to increased cell turnover.
All skin cells die and are replaced by new cells. Normally, it takes about a month for new cells to move from the lowest layer of your skin, where they form, to the outermost layer, where they die and scale off in flakes. Because cells renew themselves slowly, this process usually isn't noticeable.
But on scalps where malassezia thrives, the whole process can take as little as 11 days. The result is a large number of dead skin cells. As the cells fall off, they tend to clump together with oil from your hair and scalp, making them appear white, flaky and all too visible.
Mayo Clinic's recommendations for dandruff self-care are:
Learn to manage stress.
Cut back on styling products.
Eat a healthy diet.
Get a little sun.