There’s nothing you can do that will reverse grey hair or prevent it from happening but you may be able to delay it. Some studies have linked smoking cigarettes to premature greying. Other studies say your diet could have an impact. A deficiency in vitamin B, folic acid and biotin, which are associated with hair health, have been linked with earlier greying. Other research shows the levels of iron, calcium and vitamin D3 may play a role in going grey. Keep your hair in top condition naturally by eating a nutritious diet, refraining from smoking and following a healthy lifestyle.