The Biomedical Research Centre in Nutrition at Southampton General Hospital in the United Kingdom is one of many centres world-wide that cooperate with the IAEA in the field of nutrition studies. Under IAEA programmes, the centre provides training and technical assistance to the Agency's Member States in the use of stable isotope techniques. Stable isotopes do not emit harmful radiation, so they can be used in people of all ages. They occur naturally in the environment, in our bodies and our food. Nutrition expert, Dr. Steve Wootton, explains how these techniques can be used to help malnourished children.