The world of nutrition and nutritional supplements can sometimes be a minefield for both patients and optometrists. Whilst there is no formal training in this area for undergraduate optometrists, as primary healthcare professionals there is an existing duty to be able to advise patients on products which may help maintain the health of their eyes and vision (General Optical Council 2016). This article provides a basic introduction to health and nutrition, specifically with the optometrist in mind. Firstly, it explores what a healthy diet is and defines some commonly used terms; then it will go on to the role of nutritional supplements and how nutritional supplements are regulated. Finally it will discuss which professionals are able to give specialist nutritional advice.