Other Trace Minerals
HERE IS A brief summary on the potential hazards or benefits of some of the lesser known trace minerals. It is well to keep in mind that there is disagreement among authorities on some of these statements. As research in trace minerals is accelerated, no doubt more of the riddles will be solved.
Aluminum. It has been estimated that the aluminum content of the human diet varyies between 5 and 135 mg. daily. This metal occurs in the human body and in the bodies of animals that have never eaten food prepared in aluminum utensils; and minute amounts of it may be essential. Aluminum poses no problem in pots and pans and is, in fact, probably inert. It is a major problem in beer can litter along our roadsides, as all environmentally aware people know. (This poses one of the most troublesome problems so far as solid waste disposal is concerned.) But aluminum pots and pans and aluminum-containing baking powder pose no threat to human health. (Maybe 10 times the amounts we might get in this way can be handled by the human body.)
Antimony is toxic. It is present in some ceramics and glazes. People have been poisoned by exposure to antimony in polluted food. It is also used in toothpaste tubes, solder, ammunition, fireworks, matches, pigments, plastics, rubber or type metal. You see what our modern industrialized civilization can do when it really sets its mind to spreading some of these toxic substances around the, planet in all kinds of gadgets and trinkets.
Arsenic. It’s not toxic in small amounts, although it does cause skin problems and cancer in moderate amounts and in larger amounts it is a killer poison. If you don’t think so, find out what Abbey Brewster and her sister did to those homeless old men in Joseph Kesselring’s play, Arsenic And Old Lace. Arsenic is used in herbicides, pesticides, wood preservatives, rat poisons and cotton-growing. We should worry about high levels of this mineral in drinking water. In areas where phosphate-rich detergents are washed into waterways, the arsenic they contain goes right along into the water.
For some reason chickens and pigs grow better and thrive when a small amount of arsenic is included in their diets. It is believed that the arsenic has somewhat the same effect as antibiotics in digestive tracts, preventing infections, we suppose. If you are an the mailing list of the FDA, you will get through the mail long lists of additives permitted in the feed of poultry and animals. It is always a shock to find arsenic listed there.
The U.S. Department of Agriculture once stated that almost one out of every six chicken livers are contaminated with illegal residues of organic arsenic. They also reported that 1.7 percent of the nation’s pork livers showed illegal amounts of organic arsenic during random sampling tests. A spokesman at the USDA’s Animal and Plant Health Inspection Service in Washington, D.C., said that the organic form of arsenic used to stimulate growth is not particularly dangerous to humans in quantities found in the samples.
Barium is only slightly toxic. It is added to diesel fuel to suppress smoke. Barium is the opaque substance doctors give you to swallow when they take X-rays of your digestive tract. It is also used in glass, paint, rubber, ceramics, plastics, road flares; fireworks, sugar refining. It occurs to us that the ever-present pollution of everything near a heavily traveled highway might include barium from the rubber flakes from tires. An item from Philadelphia related that tiny, microscopic mists of rubber particles are present in enormous numbers in the Philadelphia air, due probably to the stuff that is shredded off tires along heavily traveled roads. The Air Management Services spokesman suggested washing the streets oftener to keep the rubber particles from blowing up into the air.
Bismuth is in antacids and steel products. In these preparations, it is insoluble and hence harmless. But when it appears in cosmetics—“white” lipsticks, body powders and medicines—no one knows what its potential for harm may be. Some compounds of bismuth may be given for mechanical protection of the skin or digestive tract. Often used for diarrhea, it is insoluble and hopefully harmless. Other bismuth compounds, however, were used against syphilis when arsenic was also being used to treat this disease. Bismuth given internally may cause toxic effects: skin eruptions, inflammation of the mouth and kidney irritation.
Germanium apparently occurs in our diets at the rate of about 1½ mg. per day. It is rapidly and apparently harmlessly excreted. It appears to be non-toxic to both animals and man.
Palladium causes cancer in mice. We human beings have very little exposure to it. It is in the family of platinum and is very rare.
Radium is the famous radioactive element with the extremely long half-life of 1,620 years. Because of the precautions taken, radium poisoning is rare. This element was discovered in 1898 by Madame Curie and her husband. Radium therapy has been used to treat certain diseases.
Rhodium is used to electroplate microscopes and instruments. It is in the platinum group and human exposure to it is very low, which is fortunate, since it causes cancer in mice.
Rubidium is closely related to potassium, as is cesium, another trace mineral. There is some evidence that rubidium might act as a substitute for potassium in some physiological activities. Plant foods contain about 35 ppm of rubidium, the cereal grains a bit less, and white flour much less.
Silicon is just about everywhere in the environment. It represents some 28 percent of the earth’s crust. It is a non-metallic element that occurs in plants, animals and human beings. In the human, silicon is rapidly eliminated through the urine. As an air pollutant, it is extremely dangerous to the lungs of miners and stoneworker; causing silicosis. The amount of bone ash of baby rats on a low-calcium diet is influenced by the amount of silicon in their diets and the amount of silicon in their bones is influenced by the amount of calcium as well as silicon in their diets.
Silicon has been found to be essential for good health. It is involved in forming cartilage. Tissues rich in silicon are connective tissue and cartilage, as in the trachea, the aorta, the skin and eyes. It’s significant that in aging there is a great decrease in the silicon content of the aorta of rats, chic and rabbits. (The aorta is the major blood vessel of heart.) It decreases in the skin, too, and there is tremendous drop in silicon in the thymus; in old animals there’s about 2 ppm, compared with 56 ppm in young ones.
Silver, of course, is used for all kinds of things and is generally inert and insoluble. It is used in medicine for caustic, astringent and antiseptic purposes. Mostly we know it as the silver nitrate put in newborn babies’ eyes to prevent possible blindness caused by gonorrhea. Silver preparations tend to stain the skin, so lengthy application of any silver medications on skin or mucous membranes or taking small doses internally may cause permanent bluish discoloration of the skin that is called argyria. Silver salts in large amounts are potent poisons, affecting the nervous system or the digestive tract and causing convulsions, paralysis, depression of vital centers or gastroenteritis. There is apparently no way that such disasters could afflict any of us as a result of environmental contamination.
Strontium is built into bones and teeth. It may help to prevent tooth decay and broken bones in older people. Much of it is removed when grains are refined. Strontium 90 is the radioactive form of this mineral, which floated down through the air during the bomb testing of the past decades. Since its half-life is 28 years, we can assume that most of this radioactive pollution has disappeared by now, causing us no further concern until somebody gets the idea of shooting off more nuclear bombs.
A special form of strontium called strontium ranelate can increase bone formation and prevent bone loss when used in postmenopausal women with osteoporosis. It's not known if strontium contained in dietary supplements has these effects. A radioactive form of strontium may kill some cancer cells. This type of strontium is not available in dietary supplements.
There is some interest in using strontium for osteoarthritis because developing research suggests it might boost the formation of collagen and cartilage in joints. There is also interest in studying strontium for preventing tooth decay because researchers have noticed fewer dental caries in some population groups who drink public water that contains relatively high levels of strontium.
Sulfur is found in proteins of eggs, milk, fish, poultry. It does not exist in carbohydrate or fat. Three of the essential amino acids contain sulfur. Two vitamins—thiamine (B1) and biotin, also a B Vitamin—contain sulfur. This yellowish substance is used in making gunpowder, matches, medicines and in vulcanizing rubber.
Since there appears to be no chance that anyone eating a diet that will sustain life will be short on sulfur (it is so widespread in foods), the only concern we may have about it is that it is especially important because it occurs in the amino acid methionine. Vegetarian diets tend to be short on this amino acid.
Tellurium is obtained chiefly as a by-product in the refining of copper and lead. It is toxic to workers who are exposed to it. It is found in “tin” cans. Should we worry about it? Who knows?
Tin appears to collect more readily in tissues of people in the industrialized part of the world, while in Africa there is little accumulation. Supposedly we Americans take in up to 3½ mg. daily if we regularly eat food from cans. It has been established that the person who eats a diet of mostly fresh foods like meat, vegetables and grain products might get as little as 1 mg. a day, while people who eat substantial portions of fish might get as much as 38 mg. a day. Most cans these days are lacquered, which prevents much of the contamination with whatever metals they contain. Tin is now longer used in their construction. Even so, it has low toxicity, apparently, and is excreted readily in urine and feces.
Tin is necessary at a level of 1 to 2 ppm in the diet—that much tin can be found in many plant and animal nutrients. Tin is needed for health in laboratory animals. They won’t grow without it. Extra tin in normally fed healthy animals does not produce supergrowth, however; so there is no point in would-be basketball players starting to gnaw on the family’s discarded tin cans.
Titanium is used in paints, sunburn cream and in certain alloys to impart toughness. It is, like aluminum, very abundant in the earth’s crust and in soils—but poorly absorbed by plants and animals. Most of the titanium that occurs in foods is believed to be the result of contamination. Titanium in the lungs appears to come from air pollution. No one has yet discovered that this element is essential in any way for animals or human beings
Uranium is slightly radioactive and is used in nuclear reactors. Uranium 235 may be made to undergo nuclear fission with the release of large amounts of energy. Uranium 238, another isotope, can absorb a neutron to produce Uranium 239. This spontaneously loses a beta particle of radiation to form plutonium. There is nothing you need be concerned about in all this complex situation until you are faced with a nuclear power plant in your area—at which time you will have to become very familiar with all the radioactive isotopes and their potential harm to human beings. According to nuclear physicists plutonium, derived from uranium, is the single most toxic material in the world. The Atomic Energy Commission and the electric power industry use it in comparatively large amounts in their nuclear power program. With a half-life of 24,000 years, plutonium is by far the most deadly of all the worrisome nuclear trinkets we discovered inside the Pandora’s box of nuclear fission.
Zirconium resembles titanium and silicon. It is used in flints for cigarette lighters and in antiperspirants, which can cause skin irritation. It has been found in many human tissues and its accumulation there exceeds that of some other trace minerals—copper, for example. We get, supposedly, about 3½ mg. daily—chiefly from meat, dairy foods, vegetables, cereals and nuts. There is no evidence that zirconium is harmful and also no evidence that we need it.