Effect of zinc on protein-energy malnutrition

Many of the clinical symptoms of protein-energy malnutrition (PEM) also occur in zinc deficiency. Studies show that zinc deficiency often accompanies kwashiorkor--a form of PEM. This raises the possibility of the PEM syndromes being a mixture of both protein and zinc deficiency symptoms;Four studies were done with male Wistar rats. The effects of dietary protein level and moderate zinc deficiency on PEM symptoms were examined;Regression analyses showed that PEM was initiated solely by protein deficiency. Loss of appetite and body weight were first symptoms. About two weeks later, dietary zinc deficiency caused further loss of appetite and body weight as zinc was depleted;Edema, moisture accumulation in liver (i.e., hepatomegaly), hypoalbuminaemia and mortalities were due primarily to protein deficiency;Elevated Na(\u27+) and Fe(\u27++) due to dietary zinc deficiency were seen only in the brain in both control and PEM rats, suggesting that brain disorders of PEM may be due to zinc deficiency;Excess dietary zinc appeared toxic to the PEM rats. It caused deaths significantly earlier in one study. Recovery from PEM was slower in rats fed excess zinc. Excess dietary zinc gave greater zinc absorption in PEM. However, this was significantly less efficient than absorption in control rats;Low dietary zinc caused increased tissue Na(\u27+) and vice versa. Damage to the sodium pump by zinc deficiency may be responsible. Similar relationships were seen for zinc and iron;A high incidence of eye disorders occurred in PEM rats fed zinc deficient diets. Possibly, most xerophthalmia in PEM is related to zinc deficiency;The moderate zinc deficiency did not significantly change plasma alkaline phosphatase concentrations