Academy of Science South Africa 2005/6 Annual Report

ASSAfProgramme 4Recognising excellencereading for any scientist, clinician, or student interested in iron metabolism and its disorders. South Africa providesboth unique challenges and opportunities in this field of research, because striking differences in iron balance occurin the different population groups. Varying degrees of iron overload are commonly encountered in the adult blackmale population, especially in rural areas, whereas iron deficiency occurs frequently in adult females and infants.Professor Bothwell actively engaged in researching both of these aspects. Iron deficiency, in particular, representsa pressing local and global problem and its prevention is an urgent public health priority. Although the total dietaryiron content in many cereal-based diets seemed adequate, iron deficiency anaemia was rife in populations consumingsuch diets. This seeming anomaly directed Professor Bothwell’s attention to those food factors that inhibit ironabsorption in many staple diets consumed in developing countries. He showed that polyphenols, present in tea,sorghum and legumes, were strong inhibitors of iron absorption and that the most promising enhancer of dietaryiron absorption was the chelate NaFeEDTA, which “protected” dietary iron from inhibitors during its passagethrough the stomach. Professor Bothwell foresaw that the only feasible way of tackling nutritional iron deficiencywas to fortify appropriate vehicles in the diet with bioavailable iron, and his trial in Chatsworth using curry powderfortified with iron EDTA represents a landmark demonstration that iron fortification can work. This approachis now being applied in the Far East, and collaborative studies in which Professor Bothwell is currently involvedare assessing the relative bioavailability of a number of iron powders that are being used in national fortificationprograms in many industrialised countries.Running parallel with these clinical studies were a number of basic studies concerned with physiologicalaspects of iron balance and internal iron exchange. Several seminal observations were made. The major factorsregulating iron absorption were defined (the paper reporting this finding became a Citation Classic) and thequantitative limits of iron excretion described. In addition, pioneering ferrokinetic studies were undertakenin which quantitative and qualitative aspects of erythropoiesis were defined in a wide range of haematologicalconditions. Later studies were concerned with the uptake of iron by red cell precursors, the release of iron fromreticuloendothelial cells, and the internal distribution of storage iron. A number of key biochemical and isotopictechniques were developed and described. Not surpisingly, Professor Bothwell has been a member of a number of66 Promoting Excellence in Science for Society