District focus: oral rehydration, primary health care and the scientist.

PIP: The discovery that a solution of salt and sugar is an excellent way to treat and prevent dehydration was an important advance in the primary health care field, as it was expected that mothers, even illiterate mothers, could easily learn to prepare the solution at home, thus preventing serious consequences of untreated diarrhea. In addition to the low price, an important quality of this simple solution is that it gives the mother a sense of responsibility and the knowledge that she herself can do much to alleviate the suffering of her children. Unfortunately, the pharmaceutical industry and chemists were quick to realize that big profits can be made from oral rehydration and to package ready-made solutions. Consequently, there has been a movement away from teaching the mother how to make a simple solution at home, using salt, sugar, and water. The responsibility for this situation needs to be shared by both the scientist and the health worker. Scientists seem to have some difficulty accepting the fact that simple can be good and better is not always best. By adding 1.5 grams of potassium chloride or 2.9 grams of trisodium citrate to improve the mixture, it becomes a medicine, which only can be given/prescribed/sold by health personnel or chemists. The improved formula is good in a clinic setting, but in terms of primary health care and self-help this is not the best approach. The solution is being put beyond the reach of the poor child, certainly in the rural areas of the developing world. All health workers should know how to prepare a salt-sugar solution and also should show mothers/parents/caretakers how to make it. If one is serious about primary health care and self-help, it is best to return to using sugar and salt.^ieng

Salivary zinc as an index of zinc status in women fed a low-zinc diet.

The effect of a low-zinc diet on saliva and plasma levels was studied in 12 healthy young women. A diet low in zinc (3.2 mg/day) was fed to the subjects for 22 days. Subjects were determined to be in satisfactory zinc status via analysis of the zinc levels of their diet, hair, plasma, and saliva. During the low-zinc diet, concentrations of zinc in whole mixed saliva remained relatively stable for each individual and related significantly to the percentage sediment in the saliva. However, mixed saliva zinc did not respond to dietary depletion. Plasma zinc levels declined, but not significantly. Zinc levels of salivary sediment, which consisted primarily of epithelial cells, significantly (p less than 0.05) decreased from initial values of 126 +/- 28 microgram/g to final levels of 94 +/- 14 microgram/g after the low-zinc diet. These results suggest that mixed saliva zinc is not a useful index of zinc status; however, salivary sediment zinc may be a sensitive parameter if contamination can be avoided.

Zinc and copper content of foods used in vegetarian diets.

The zinc and copper content of seventy-four foods was determined by atomic absorption spectrophotometry. Each of these foods was reported to have been consumed by practicing vegetarians. Legumes, seeds, nuts, whole grains, hard cheeses, and some nutritional supplements were found to be excellent sources of both zinc and copper. Vegetables, fruits, and their products were generally poor sources of trace minerals, with the exception of seed and bean sprouts. Milk and milk products, including rennetless cheeses, contain small quantities of these minerals. Although many of the foods consumed by vegetarians do contain adequate amounts of zinc and copper, their bioavailability may be limited.

Alterations in zinc absorption and salivary sediment zinc after a lacto-ovo-vegetarian diet.

The effect of a lacto-ovo-vegetarian diet on plasma zinc tolerance tests and plasma and saliva zinc levels was measured in 12 nonvegetarian women. A diet meeting the Recommended Dietary Allowances for all nutrients, including zinc, was fed to the subjects for 22 days. Initial zinc status of subjects was determined by zinc analysis of their diet, hair, plasma, and saliva. Plasma response to an oral load of 50 mg Zn was determined in five subjects before and after the dietary period. Zinc levels of salivary sediment, which consisted primarily of epithelial cells, significantly decreased from initial values of 128 to final levels, of 94 microgram/g. No significant differences were found in zinc levels of plasma or whole mixed saliva. Plasma response to initial zinc tolerance tests were inversely correlated (P < 0.05) to dietary protein levels. Significantly increased plasma zinc uptake and areas under zinc tolerance curves were found after consumption of vegetarian diets compared to diets containing meats. The increased plasma response to a zinc load and decrease in salivary sediment zinc after a vegetarian diet indicate that this diet adversely affects zinc status.