Amounts leading to toxicity: What level of cadmium causes toxicity is not clear; zinc levels in the body play a role in determining this. Estimates of daily cadmium exposure range from 25 to more than 200 mcg., mostly from food. About 40-50 mcg. daily is probably a safe guess. This should be handled fairly well by a normally functioning body. Below 2 ppm in hair and .015 ppm in whole blood are considered current normal ranges for body cadmium levels.

Who is susceptible? People who have higher exposure to cadmium are at higher risk. Industrial workers, metal workers, zinc miners, and anyone who works with zinc galvanization may accumulate more cadmium. Those who drink soft water; those who smoke or whose friends, roommates, or coworkers smoke; coffee and tea drinkers; and those who eat refined flours, sugars, and white rice are also likely to receive greater exposure to cadmium.

Treatment: Intravenous EDTA chelation is effective in increasing cadmium elimination, though this is probably indicated only at more toxic levels. Avoiding further cadmium exposure is emphasized. High intake of zinc as well as of calcium and selenium will protect against further cadmium absorption, and adequate body levels of zinc may displace some tissue cadmium. Iron, copper, selenium, and vitamin C have been shown to increase cadmium elimination as well, as can be measured by urine levels. Hair analysis is a good way to follow cadmium levels.

Prevention: With good health, cadmium is probably not a problem unless there is increased exposure, zinc deficiency, or weakened kidney function. Cadmium toxicity also seems to be a little worse with lead intoxication. There are two good ways to protect against cadmium toxicity. The first is to avoid cadmium exposure and intake-primarily by minimizing smoking and exposure to cigarette smoke, avoiding refined foods, shellfish, coffee, tea, and soft water. Air contamination is usually minimal compared to that from food and water. The second way to protect against cadmium toxicity is to maintain good zinc levels by eating high-zinc foods, such as whole grains, legumes, and nuts (oysters are high in zinc but also high in cadmium). Taking additional zinc, 15-30 mg. daily in a supplement, will offer further protection against cadmium problems.