Selenium in human health and disease with emphasis on those aspects peculiar to New Zealand.

Evidence is accumulating to suggest that selenium (Se) is an essential trace element for man and is reviewed with emphasis on those aspects peculiar to New Zealand. The extremely low Se levels in New Zealand soils results in a low Se content of foods, low dietary intakes, low urinary excretions, and low blood Se concentrations and glutathione peroxidase activities. Of these, plasma Se gives a short-term index of nutritional status while erythrocyte Se and glutathione peroxidase activities give a long-term index. The consequences of the low Se status of New Zealanders are not immediately apparent as a deficiency disease has not been detected in residents consuming a normal diet. However a Se-responsive muscular syndrome has been described in a surgical patient on total parenteral nutrition. Similar groups that might be vulnerable to a Se deficiency are children with metabolic disorders consuming synthetic protein diets, premature babies and infants during the first few months of life, and patients with cancer whose lowered dietary intake is coupled with the traumatic nature of their disease. Other groups that have been studied in relation to a possible role for Se in specific illnesses are patients with cardiovascular disease and hypertension, rheumatoid arthritis and other muscular syndromes and surgical patients with or without cancer. It is not yet possible to predict a minimum Se requirement for health but it appears that the intake of New Zealanders might be on the borderline. At present supplementation by the general population is not justified, but may be necessary for certain vulnerable groups such as patients on restricted diets. The most effective means of supplementation for increasing the Se status of New Zealanders is under study.