In the human body, the 2.5 grams of zinc are stored in a variety of tissues. It is most concentrated in the prostate and semen, which suggests zinc's tie to male sexual function (impotence can be related to low zinc). The next most concentrated tissues are the retina of the eye, heart, spleen, lungs, brain, and adrenal glands. The skin contains a high amount of zinc, but it is less concentrated than in the organ tissues. Nails, hair, and teeth also have some zinc, and this mineral is important to those tissues as well.

Zinc is eliminated through the gastrointestinal tract in the feces. Some is also eliminated in the urine; alcohol use increases urinary losses of zinc. Zinc is also lost in the sweat, possibly as much as 2-3 mg. in a day. Stress, burns, surgery, and weight loss all seem to increase body losses of zinc.

In evaluating body zinc status, plasma or serum zinc levels may not reflect body stores; however, if they are low, zinc is likely deficient. Low hair levels appear to reflect zinc deficiency, which then should be substantiated through a blood test. High hair zinc levels may also be seen with zinc deficiency, though this is not as correlative as low hair levels. In general, the red blood cell (or white blood cell) measurement of zinc may be most indicative of the body's true status of zinc nutriture.

Sources: Most animal foods contain adequate amounts of zinc. Oysters are particularly high, with more than ten times as much as other sources (they are also high in copper and, possibly, in ocean-polluting chemicals and metals). Zinc is added to animal feeds to increase growth rates, so meat usually contains high amounts. Red meats (beef, lamb, and pork) and liver are fairly high; herring is good, as are egg yolks and milk products (though the zinc in eggs and milk products may not be as available to the body as that found in other sources). Other fish and poultry also contain fair zinc levels. As with iron, the zinc in animal foods seems to be better absorbed than that in the vegetable sources, but one can reduce meat foods and eat whole grains and beans and still obtain adequate zinc. Overall, though, in my experience it is not easy for most people eating a relatively healthy diet to obtain the minimum requirement of 15 mg. daily unless they focus on zinc-containing foods.

Whole grains such as whole wheat, rye, and oats are rich in zinc and are good sources for vegetarians. Even though the mineral from these foods is utilized less well because the fiber and phytates in the grain covering bind some zinc in the gastrointestinal tract, much of the zinc in these foods is still available to the body. Nuts are fairly good sources, with pecans and Brazil nuts the highest. Pumpkin seeds contain zinc and are thought to be helpful to the prostate gland. Ginger root is a good zinc source, as are mustard, chili powder, and black pepper. In general, fruits and vegetables are not good zinc sources, although peas, carrots, beets, and cabbage contain some zinc.

The zinc in grains is found mainly in the germ and bran coverings, so refining them will lower the zinc content. Approximately 80 percent of zinc is lost in making white flour from whole wheat. Since zinc is soluble in water, canning foods or cooking in water can cause zinc losses. Zinc losses have also been prevalent in agricultural soils, and it is therefore less available in foods. Chemical fertilizers also decrease zinc soil levels. Many soils-nearly 30 states in the United States-are deficient in zinc. Water, especially from some wells, contains zinc. Water was a better source when some of the water pipes were galvanized (containing zinc), as were some cooking pots. Now, water pipes are more commonly made of copper, which can become toxic at higher levels.