Ten Vital Trace Minerals
For Some Minerals, a Tiny Amount Can Go a Long Way
- Tis a superstition to insist on a special diet.
All is made at last of the same chemical atoms.
- Ralph Waldo Emerson
Well, yes and no, Mr. Emerson. Perhaps you understood the principles of chemistry a bit better than those of nutrition. Although it's true that every carbon atom, for example, is identical to every other carbon atom in its chemical properties, regardless of whether it came from an eggplant or a power plant, man does not live by carbon (and hydrogen, oxygen, nitrogen, phosphorus, and sulfur) alone. These elements - the major bioatoms - do indeed make up the chemical backbone of life as we know it, but there's more to life than backbone.
Life also depends critically on a variety of "micronutrients" - substances present in the body in extremely small amounts - including the vital trace elements. They're vital because without them we would die. Dietary deficiencies of these elements can cause a variety of illnesses, so it is essential that we ingest adequate amounts of them on a daily basis. That often does require a "special diet" to compensate for Mother Nature's occasional oversights in the minerals department.
Ingesting just enough of the trace elements to prevent disease is not necessarily the best strategy, however, as we will see later. For optimal health, it is preferable to supplement with judiciously chosen amounts of these minerals. That is now possible with ten of the most important trace elements.
Just how important the trace elements, along with the other micronutrients, are for our health is perhaps best summarized in a scientific paper published in 1998 by the renowned biochemist and cancer authority Bruce Ames, of the University of California, Berkeley. Dr. Ames stated,1
"Approximately 40 micronutrients (the vitamins, essential minerals, and other compounds required in small amounts for normal metabolism) are required in the human diet. For each micronutrient, metabolic harmony requires an optimal intake (i.e., to give maximal life span); deficiency disrupts metabolism in numerous and complicated ways. The recommended daily allowance (RDA) of a micronutrient is currently based on information of acute effects, rather than long-term health, an area which has been little studied; however, for many micronutrients, a sizable percentage of the population is deficient relative to the current RDA. Remedying these deficiencies, which can be done at low cost, is likely to lead to a major improvement in health and an increase in longevity."
WHAT ARE THE TRACE ELEMENTS?
Trace elements, as the name implies, are those that we need to ingest only in tiny amounts - typically in the range of micrograms to milligrams per day - in order to maintain levels conducive to good health. It is generally accepted that the nine vital trace elements - the ones without which good health (or even life itself) would not be possible - are chromium, cobalt, copper, iodine, iron, manganese, molybdenum, selenium, and zinc. These are the ones that play absolutely essential (and, for the most part, fairly well-understood) roles in myriad aspects of human physiology.
The other trace elements - those that are not vital in the Big Nine sense but that are nonetheless believed (with widely varying degrees of evidence) to be essential to our health - are aluminum, arsenic, boron, bromine, cadmium, fluorine, germanium, lead, lithium, nickel, rubidium, silicon, tin, vanadium, and perhaps others. Of these, fluorine may be the one that is not truly essential, but it is beneficial.2 The surprise entries in this list are arsenic, cadmium, and lead, which are notorious poisons, but even poisons can have positive qualities in small enough quantities, as anyone who has received strychnine as a medicine can attest.
All categories of foods - fruits, vegetables, legumes, nuts, grains, meats, seafood, etc.- are potential sources of trace elements, most of which are present there in the form of inorganic salts. When we eat them, they are absorbed by the stomach or intestines and are then carried by the blood to target sites throughout the body, either as free ions or bound to protein carriers. Their distribution throughout the body may be very uneven, depending on where they are most needed. Most of the iodine we ingest, e.g., goes to the thyroid gland, with a small amount going to the ovaries and a few other places. Ultimately, the trace elements are excreted in the bile, urine, stool, and sweat, which is why we must continue to consume them.
WHAT DO THE TRACE ELEMENTS DO?
Most of the evidence for the essentiality of many of the trace elements is circumstantial, i.e., it is based on observations of deficiency symptoms (from either accidental or induced deficiencies) and the response of those symptoms to dietary supplementation with the elements in question, rather than on direct evidence of the biochemical roles played by the elements.3
The roles that we do know about fall into three broad categories: (1) catalytic, in which the element is a component of an enzyme cofactor (also called a coenzyme), without which the enzyme could not perform its function as the catalyst for a particular chemical reaction, such as one involved in cellular metabolism or cellular reproduction; (2) structural, in which the element is a component of a physiologically vital molecule, such as hemoglobin (trace element: iron), thyroxine (iodine), or cyanocobalamin (cobalt), and (3) regulatory, in which the element interacts chemically with macromolecules in such a way as to enhance or inhibit their function. Taken together, the trace minerals are involved in all major metabolic pathways and are thus of fundamental importance in human physiology.4
DOES OUR DIET CONTAIN ENOUGH OF THE TRACE ELEMENTS?
Complacency can be harmful to your health. It is important to realize that we do not necessarily get enough of all the trace elements we need in our diet, even if it's an otherwise healthy one that follows generally recommended standards with regard to the main food groups. Whether such a diet contains enough of a certain trace element depends mainly on the mineral content of the soil in which the crops that go into that diet are grown (or the mineral content of the soil that grew the grass that fed the cow that gave the milk that you poured on your breakfast cereal).
The soil in some geographic regions is known to be deficient in this or that trace element, so foodstuffs derived from that soil will be deficient also. This can be a problem for those whose food comes primarily from that region rather than from diverse regions. But if the region in question is large enough - the entire country of New Zealand, e.g., is low in selenium - virtually everyone can be affected. Many other places throughout the world are low in selenium, including parts of China, Egypt, and the United States.
Of course, those who eat a poor diet that is unbalanced with regard to the main food groups are much more likely than their more sensible friends to suffer some trace-element deficiencies. In either case, however, the crucial question is: deficiencies of which trace elements? There is no easy way to know, because there are so many dietary variables involved. And, unless the deficiencies are so serious that they cause overt disease (which is rare, especially in the developed nations), their symptoms are usually very hard to identify as such, because there is a great deal of overlap among them, and most of them can easily arise from many other causes as well. The most common symptoms are malaise, loss of appetite, anemia, infections, skin lesions, and low-grade neuropathy (a disease or abnormality of the nervous system).5
WHAT IS GOOD HEALTH AND HOW GOOD IS IT?
Regarding nutrition in general, it is widely taken for granted that one of the main objectives of a balanced diet is to ensure that we get enough of all the vital nutrients our bodies need to prevent deficiency symptoms for any of those nutrients. For example, if we get enough vitamin C, we won't get scurvy. The implicit assumption here is that good health is the absence of disease.
What a ridiculous notion! As readers of Life Enhancement know, ingesting just enough of the essential nutrients to avoid their deficiency symptoms is hardly the basis of good - let alone optimal - health. We know that many nutrients keep on delivering health benefits, the more of them we ingest - up to some reasonable limits, beyond which toxic effects can begin to occur. Within those limits, more is generally better. Without question, good health is better than minimal health (the absence of disease), and optimal health is best of all. It's the difference between reaching for the stars and reaching for the top of your head.
There is no reason to believe that this principle does not apply to the trace elements and other micronutrients as well as to the better-known macronutrients, and some scientists (even government scientists!) are beginning to acknowledge it. Listen to Dr. Forrest H. Nielsen of the U.S. Department of Agriculture's Human Nutrition Research Center in Grand Forks, ND:3 "A new paradigm is emerging in which the dominating role of the concept of deficiency in the determination of nutritional requirements is gradually being complemented by the concern for the total health effects of a nutrient. In other words, dietary intake recommendations for nutrients are being made that far exceed those required to prevent deficiency pathology because of apparent beneficial health effects."
We couldn't have said it better ourselves. (OK, maybe we could have, but let's not quibble.) What's important to remember is that, although it is usually difficult to know for sure whether one is getting enough of a given trace element in the diet to ensure at least good health, it is easy to guarantee getting enough by taking intelligently designed supplements. The intelligence comes in the form of ensuring that the amount taken is well within the limits of safety at both ends of the spectrum: not too little, certainly, but also not too much.
WHO NEEDS MORE TRACE ELEMENTS?
An interesting question is whether or not the elderly are at greater risk of trace-mineral deficiencies, in analogy with their known tendency to a low dietary intake of the "macrominerals" such as calcium and magnesium. Among the reasons for believing that this could be true are: changes in appetite and in the senses of smell and taste brought on by medications; lowered food intake owing to difficulties in chewing or swallowing; and changes in endocrine function as well as in gastrointestinal and renal physiology, which could alter the requirements for some minerals. Whether or not the elderly do need higher average daily intakes of some trace elements remains largely an open question, however. There is little hard evidence either way.6
In any case, the health-conscious consumer of any age nowadays is bombarded with all kinds of claims - many of them specious and irresponsible - regarding the trace elements and the so-called "cures" they can provide for everything from arthritis to zits. It is difficult to find honest, reliable, scientifically sound advice on this subject in publications written for the layman. But that's why you're reading Life Enhancement, isn't it?
Based on extensive examination of the scientific literature on trace elements, we have created a formulation of ten of these elements for which deficiencies are most likely to occur in the modern American diet. They are boron, chromium, copper, iodine, magnesium, manganese, molybdenum, selenium, vanadium, and zinc. Following are capsule descriptions of each of these elements.
Boron deficiency in chicks (the kind with feathers) causes impaired calcium and energy metabolism, altered bone morphology, and an increased vitamin D requirement.3 These findings are consistent with the belief that boron in humans may be beneficial for optimal calcium metabolism and thus optimal bone metabolism.7 There is epidemiological evidence that arthritis is much more prevalent in areas of the world where boron levels are unusually low, suggesting that this may be a primary effect of boron deficiency.8 A reasonable amount of supplemental boron is 3 mg/day.
The role of chromium in the body is in glucose and lipid metabolism, and a dietary deficiency can cause impaired glucose tolerance, which is of great importance to diabetics. Oral supplementation with chromium corrects this problem in patients with Type 2 (maturity-onset) diabetes mellitus and in children with protein-energy malnutrition, but such supplements have no effect in people with normal chromium intakes or in those with normal glucose tolerance.4 A reasonable amount of supplemental chromium is 200 mcg/day.
Copper is found in all living cells and is essential for proper function of the immune system. With zinc, it is part of a complex called copper/zinc superoxide dismutase, which is an extremely important antioxidant enzyme. A copper deficiency impairs the function of this enzyme and leads to various diseases affecting the blood, the cardiovascular system, the skeleton, and the central nervous system.5 Adequate intake of copper is especially important for obese women during weight loss, and it has been known for decades that a copper deficiency can cause osteoporosis.9 A reasonable amount of supplemental copper is 2.5 mg/day.
Iodine is absolutely vital for proper thyroid function, and its deficiency is probably the most dramatically visible of all, as it produces goiter, a pronounced swelling of the thyroid gland, which is located in the front of the neck. Severe cases cause mental retardation, even cretinism, and are thus among the most devastating of all trace-element deficiencies. Although iodine deficiency was virtually eliminated in the developed world in the 1920s through the brilliantly simple expedient of adding a pinch of iodine to our commercial table salt, it has been making a "comeback" in recent years and thus represents a growing threat to good health even in some Western countries.10,11 It has always been a major health problem in most underdeveloped countries. (By the way, it's pronounced "eye-oh-deen," not "eye-oh-dine." The latter pronunciation applies only to the antiseptic tincture you buy at the drugstore.) A reasonable amount of supplemental iodine is 100 mcg/day.
Interest in the role of magnesium in clinical medicine, nutrition, and physiology has recently increased. Magnesium is used in several hundred chemical reactions in the body.12 It possesses special binding characteristics that contribute to its effects on many cellular functions, including the transport of potassium and calcium ions. It also modulates signal transduction, energy metabolism, and cell proliferation, and it is now thought to have a role in the prevention and treatment of vascular headaches. Magnesium deficiency is not uncommon among the general population: its intake has decreased over the years, especially in the Western world. Deficiency is related to atherosclerosis, cardiac diseases, diabetes, and asthma. A reasonable amount of supplemental magnesium is 450 mg/day.
Although manganese is found in very few enzymes in the human body, it plays a role in activating a wide variety of enzymes, and that too makes it essential. Evaluating just how important manganese really is has proved to be difficult, however, because there is only one recorded case of a human manganese deficiency - and that was induced accidentally through an error in an experimental diet. The patient in question developed weight loss, decreased serum levels of cholesterol, triglycerides, and phospholipids, and a blood-clotting abnormality that did not respond to vitamin K until manganese was given. In any case, extrapolations from animal studies indicate that manganese deficiency can produce abnormalities in the metabolism of carbohydrates, glycosaminoglycans, and cholesterol.4 A reasonable amount of supplemental manganese is 8 mg/day.
In the human body, molybdenum tends to be concentrated in the liver, kidneys, skin, and bones. A deficiency is characterized by mouth and gum disorders and mental disturbance, among others.5 It produces a distinctive syndrome of impaired metabolism of sulfur-containing amino acids (constituents of proteins) and nucleotides (the basic constituents of DNA and RNA).4 A reasonable amount of supplemental molybdenum is 80 mcg/day.
Selenium is widely distributed throughout the body, with high concentrations in the kidneys, liver, and testicles. Selenium-containing enzymes - notably the vital antioxidant glutathione peroxidase - play a major role in protecting the integrity of cell membranes and the immune system, and they help maintain the function of the thyroid gland and the heart.5 An interesting aspect of the selenium in glutathione peroxidase is that it is synergistic with vitamin E (another antioxidant); consequently, a deficiency in either of these nutrients can create additional requirements for the other.4 Selenium has been shown to increase sperm motility (and hence the probability of conception) in subfertile men with low selenium levels.13 And there appears to be strong evidence that a low selenium intake is associated with higher cancer rates, suggesting that an adequate selenium intake may be essential for cancer prevention.14 A reasonable amount of supplemental selenium is 200 mcg/day.
Vanadium is widespread in both the plant and animal worlds, but in low concentrations: most foods contain less than 1 part per billion. The estimated daily intake of the U.S. population ranges from 10 to 60 micrograms.15 Although known for more than a hundred years, its hypoglycemic properties were established only in 1985. Recent research shows that it has an insulin-like effect on blood-sugar levels. Vanadium is also known to play a role in the regulation of intracellular signaling and as a cofactor of enzymes essential in energy metabolism. A reasonable amount of supplemental vanadium is 20 mcg/day.
Zinc is the champion trace element, being active in over 400 proteins, in the interactions of hormones with their receptors, and in synaptic transmission in the nervous system.1 The influence of zinc is so pervasive, encompassing all the major metabolic pathways, that it has been compared in importance to an essential amino acid.16 It is second only to iron in total amount in the body and is found in high concentrations in the male reproductive system as well as in muscle, bone, liver, kidneys, skin, and hair.
Evidence from both animal and human studies indicates that a zinc-deficient diet can cause chromosomal damage, esophageal cancer, male infertility, alterations in brain development and growth, learning and behavioral disabilities, cognitive defects, immune-system dysfunction, and slow growth and development in newborns, among others.1 Zinc is believed to play a role in neural functions such as appetite control, taste, olfaction, vision (particularly dark adaptation), abstract thought, and neuromuscular coordination.4 Wound healing and the integrity of cellular membranes are highly dependent on adequate amounts of zinc.5 It has even been suggested that an intracellular zinc deficiency may be the primary cause of the aging process.17 A reasonable amount of supplemental zinc is 20 mg/day.
MR. EMERSON, MEET MR. THOREAU
The finest qualities of our nature, like the bloom on fruits,
can be preserved only by the most delicate handling.
Yet we do not treat ourselves nor one another thus tenderly.
- Henry David Thoreau
The science of trace minerals and the art of supplementation are allied, as Mr. Thoreau implies, albeit in another context. Thus, it is extremely important that we provide ourselves with sufficient mineral nutrition to allow us to achieve the finest qualities of which we are capable. Our bodies are biochemical factories that require the finest raw materials, in the proper amounts, for them to function optimally.
- Ames BN. Micronutrients prevent cancer and delay aging. Toxicol Lett 1998;102-103:5-18.
- Saudin F, Gelas P, Boulétreau P. The trace elements in artificial feeding. Art and practice. Ann Fr Anesth Réanim 1988;7(4):320-32.
- Nielsen FH. How should dietary guidance be given for mineral elements with beneficial actions or suspected of being essential? J Nutr 1996 Sep;126(9 Suppl):2377S-85S.
- Aggett PJ. Physiology and metabolism of essential trace elements: an outline. Clin Endocrinol Metab 1985 Aug;14(3):513-43.
- Chan S, Gerson B, Subramaniam S. The role of copper, molybdenum, selenium, and zinc in nutrition and health. Clin Lab Med 1998 Dec;18(4):
- Wood RJ, Suter PM, Russell RM. Mineral requirements of elderly people. Am J Clin Nutr 1995 Sep;62(3):493-505.
- Meacham SL, Taper LJ, Volpe SL. Effect of boron supplementation on blood and urinary calcium, magnesium, and phosphorus, and urinary boron in athletic and sedentary women. Am J Clin Nutr 1995 Feb;61(2):341-5.
- Newnham RE. Essentiality of boron for healthy bones and joints. Environ Health Perspect 1994 Nov;102 Suppl 7:83-5.
- Klevay LM. Lack of a recommended dietary allowance for copper may be hazardous to your health. J Am Coll Nutr 1998 Aug;17(4):322-6.
- Delange F, Burgi H. Iodine deficiency disorders in Europe. Bull World Health Organ 1989;67(3):317-25.
- Lee K, Bradley R, Dwyer J, Lee SL. Too much versus too little: the implications of current iodine intake in the United States. Nutr Rev 1999 Jun;57(6):177-81.
- Swain R, Kaplan-Machlis B. Magnesium for the next millennium. South Med J 1999 Nov;92(11):1040-7.
- Scott R, MacPherson A, Yates RW, Hussain B, Dixon J. The effect of oral selenium supplementation on human sperm motility. Br J Urol 1998 Jul;82(1):76-80.
- Fleet JC. Dietary selenium repletion may reduce cancer incidence in people at high risk who live in areas with low soil selenium. Nutr Rev 1997 Jul;55(7):277-9.
- Barceloux DG. Vanadium. J Toxicol Clin Toxicol 1999;37(2):265-78.
- Golden MHW, Golden BE. Trace elements: potential importance in human nutrition with particular reference to zinc and vanadium. Br Med Bull 1981;37:31-6.
- Garfinkel D. Is aging inevitable? The intracellular zinc deficiency hypothesis of aging. Med Hypotheses 1986 Feb;19(2):117-37.