The last mineral topic we covered dealt with sodium and potassium. Important stuff, this mineral balance. Recall that the amounts of minerals needed by the body are not an indication of their importance, and that we probably can’t get all that we need from our foods because of untrustworthy practices from seed to table. Remember, too, that kids, especially, need to eat the plants to get the minerals. The recommended number of servings of fruits and vegetables is now nine to thirteen, up from five to nine. Either way, how many people do you know who eat that much?
Copper and zinc are antagonists, and the balance between them is an example of biological dualism. This does that, and that does this, and they often fight with each other. Kind of a simple explanation, but maybe you get it. Yes, it’s possible for there to be zinc toxicity and copper toxicity. In the past, it’s been copper toxicity and zinc deficiency. Today it might be just the reverse, considering that people take supplements without the faithful reading of labels. Both minerals play important roles in the body.
Copper is necessary for blood vessel formation, a strong heart and for stabilizing collagen. You know what collagen is…the glue that holds us together. We need copper for brain development and for communication between nerve cells in the brain. Copper is essential to a number of enzymes involved in energy production by the mitochondria. It helps to make superoxide dismutase to get rid of reactive oxygen species (free radicals). Because it’s found in a number of foods, copper deficiency is not common. Meats, shellfish, nuts, and seeds are premier sources, followed by mushrooms, lentils, shredded wheat and chocolate. Daily intake by adults normally is a little more than a milligram, which is only a bit higher than the RDA of 0.9 mg. The tolerable upper limit for adults is 10 mg, while most supplements contain 2 mg. Infants fed a cow’s milk diet are the ones most likely deficient because milk has little copper, but people with malabsorption disorders are close behind. Anemia and low white blood cell count are signs of deficit. Take care to note that very high doses of vitamin C might interfere with copper-related enzyme efficiency (Finley, 1983). But that’s not written in stone. Zinc overdose, however, might be a legitimate cause of copper deprivation.
Now, here’s the rub with zinc. Concerns arise when you take several supplements that each contain zinc. The tolerable upper limit, the dose above which there may be adverse reactions, is 40 milligrams for an adult. Let’s see, Hmm, prostate formula contains 15 mg; cold/flu formula contains 15 mg; daily multi-vitamin contains 15 mg; nasal spray contains 5 mg; other zinc complexes aimed at myriad conditions contain more… Can you see where we’re going? Copper deficiency now becomes a possibility. The need for zinc hovers around 11 mg for a guy, about 8 mg for a non-pregnant female.
Zinc is needed for steroid hormone synthesis, being a well-known catalyst for testosterone manufacture as well as luteinizing hormone, the one that stimulates ovulation. Of all the body parts, the prostate contains the highest concentrations. More than a hundred different enzymes rely on zinc for their ability to catalyze chemical reactions in the body. It plays a structural role in the superoxide dismutase mentioned in the earlier paragraph and in the integrity of the cell membrane. In fact, the loss of zinc from biological membranes increases their susceptibility to oxidative damage (O’Dell, 2000). Then, we have these nifty little things called zinc fingers, which are transcription factors that bind to DNA and influence specific genes, which are stabilized by the presence of zinc. Taking too much zinc over a period of a few weeks will upset copper bioavailability, possibly resulting in hematology issues down the line. Meanwhile, the bioavailability of folate/folic acid/folinic acid is enhanced by zinc.
Zinc deficiency usually follows genetic disorders and is identified as such. Immune deficiencies, impaired healing, diminished sense of taste (and perhaps smell), night blindness, opacity of the cornea, behavioral disturbances, and delayed maturation are common signs of low zinc values. Deficiency in children is dramatic in that neuropsychological development is impeded and susceptibility to life-threatening infections is increased (Hambidge, 2000).
Do those zinc lozenges advertisements have any immune system merit? We know that zinc deficiency causes immune dysfunction, but there is mixed commentary on the efficacy of zinc mega-doses for colds and other viral infections in people with ample zinc stores (Baum, 2000) (Salqueiro, 2000) (Fraker, 2000). The immune system relies on more than just zinc for its competence. Essential amino and fatty acids, selenium and iron, folic acid and vitamins B6 and B12, and vitamins E, A and C have a say in the immune system’s function. Consider, too, that a deficiency in one of these is likely to follow a deficiency in one or more of the others. Intakes of nutrients in excess of the recommendations do not necessarily translate to a boost in all immune activity unless a deficiency has been identified. Even then, despite the disparity in research conclusions, mega-doses of one mineral can knock another one out of the ring. On the other hand, using zinc lozenges as soon as cold symptoms appear seems to reduce severity and duration, depending on the formulation (Singh, 2011).
Balancing copper and zinc, though vitally important, may not be as easy as expected. Exposure to other metals, especially to lead that may originate from ancient water pipes, contaminated ground water, the shooting sports, some toys and paints,and fishing sinkers, can push zinc out. Iron, particularly from a supplement, may inhibit intestinal absorption of both zinc and copper through competition for transport molecules located in the gut. Wilson’s disease, the inability to metabolize copper out of the body, requires a dietary change that precludes mushrooms, nuts, chocolate, shellfish and dried fruits, and includes zinc therapy (Chasapis, 2012). The testing for zinc and copper values is not completely established because reference ranges are based on statistical averages, not on optimum functional levels. As with other nutrients, availability from foods is too often questionable, but supplementation should to be considered under the guidance of a knowledgeablenutrition professional, such as a credentialed nutritionist or dietitian. A caveat: Don’t even think about drinking water from a galvanized container. There are reports of a family that had collected its drinking water from a brand new refuse container and suffered from zinc overdose. Some denture adhesives contain zinc. Be careful. Read labels.
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*These statements have not been evaluated by the FDA. These products are not intended to treat, diagnose, cure, or prevent any disease.
February 05, 2013