Zinc-lead link.

Sometimes too little of one thing can lead to too much of another. Mary Hale Ashraf and Gary J. Fosmire of the Pennsylvania State University in University Park report in the March JOURNAL OF NUTRITION that rat pups with low levels of zinc accumulated more lead in their bodies than pups considered zinc-adequate.

Lead damages the nervous system, and is particularly dangerous to children. Indications are that many people in the United States don' get their "recommended daily allotments" of zinc, Fosmire says. Meat, eggs, milk and legumes are high in zinc. "Provision of an adequate level of zinc in the diet would seem to lessen the danger of lead exposure," says Fosmire. That's not to say high doses of zinc will stave off lead poisoning, he notes. Excess zinc doesn't add further protection and in large doses may have adverse effects.

Fosmire and Ashraf created the zinc deficiency by feeding the pups' dams a low-zinc diet so that their milk was also low in zinc. While other studies have shown a link between severe zinc deficiency and lead accumulation, the Penn State researchers created a marginal deficiency, closer to what happens in humans, Fosmire notes.