Minerals and Trace Minerals

Minerals form the inorganic basis of the human body, the basic structure on a molecular level of all the different tissues including the bones, muscles, skin and hair. If we were to reduce the body to ash, we would have on average about five pounds of minerals, most of which would be calcium and phosphorus, as well as a little iron, sodium, potassium and other elements including magnesium.  

Although the body is mostly comprised of elements that combine to form organic materials, including carbon, oxygen, hydrogen and nitrogen, minerals play a key role not just in providing physical structure but in regulating innumerable aspects of physiological function. Sodium and potassium for example play a key role in neurological function, propagating a nervous impulse along a neuron by moving through voltage-gated ion channels. Calcium and magnesium allow for muscle contraction and relaxation, iodine in the production of thyroid hormone, and copper in the electron transport chain that produces ATP, the energy ‘currency’ of the body. The importance of minerals has long been recognized in traditional medicine, from the use of mineral-rich animal tissues such as bones in medicinal broths to promote healing, as well as inorganic minerals such as salt, alum and zinc mined from the earth.

Up until relatively recent, humans obtained all of their dietary requirements for minerals in their food, allowing nature and geography, as well as traditional dietary practices satisfy their requirements. With the advent of modern agriculture and the industrial refinement of our food however there has been a dramatic shift in the overall mineral density of our food. The reliance of modern agriculture upon inorganic fertilizers such as nitrogen, phosphorus and potassium (NPK) instead of traditional methods of soil management including composting and crop-rotation, has promoted a 400% decrease in the average mineral content of our food since 1914 (Bergner 1997, 72). The addition of inorganic nitrogen to the soil has been shown to deplete the vitamin C and iron content of crops, whereas chloride from potassium chloride leaches the soil of zinc, magnesium and calcium, and inhibits selenium absorption in plants (Bergner 1997, 53-55). The industrial refinement of our food, used to prolong shelf life as well as improve flavor and texture, has promoted a dramatic loss of nutrients, with 50-99% reductions of key minerals including magnesium, chromium, zinc, manganese and copper in common foods such as wheat and sugar (Haas 1992, 159). Dietary mineral deficiencies appear to be a key aspect in the increasing incidence of chronic degenerative disease and immunodeficiency in the Western world. On average, about 43% of the population in the United States is deficient in key minerals and special nutrients and the average American diet only contains 40-50% of the recommended daily allowance (RDA) for calcium, 50% of the RDA for copper, 50-60% of the RDA for magnesium and 50% of the RDA for selenium (Pizzorno 1996, 198). It is important note that the RDA is considered by many to be at the very low end of the spectrum, and does not take into account the increased needs of certain minerals due to changes that have occurred in our diet and lifestyle over the years. For example, in people with low stomach acid (hypochlorhydria), which is a possible result of chronic emotional stress, the absorption of chromium, copper, iron, magnesium, manganese, molybdenum, selenium and zinc is significantly impaired (Bergner 1997, 272).

The good news is that there are many foods that are excellent sources of minerals. Pizzorno reports that organically grown foods contain an average of 96.33% higher levels of organic minerals than conventionally grown foods (1996, 198). Other mineral rich foods include lamb, goat meat, organic organ meats, wild meat, sea vegetables, medicinal herbs and glacial water. For convenience sake, and as a part of a therapeutic program, there are several products that can be taken to boost mineral status, including kelp tablets, liquid trace minerals, ionized sea water supplements, mineral chelates and colloidal minerals. While minerals certainly have health-giving and therapeutic properties, I tend to recommend against the ingestion of large amounts of any one mineral simply because one mineral can inhibit the absorption of another. Thus I always recommend that the therapeutic use of any given mineral be given with a multi-mineral supplement in order to avoid competitive absorption.

The following is a selected overview of some key minerals, including calcium, magnesium, iron, zinc, iodine, copper, chromium and selenium.

Calcium

Calcium is an important macromineral, needed in significant quantities but is poorly absorbed in the gut, specifically requiring cholecalciferol (vitamin D3) for absorption. In the heart and blood vessels calcium is a key nutrient that regulates contraction, and deficiencies often observed to cause vasoconstriction. Dietary deficiencies may also promote the mobilization of calcium from bone to soft tissues, from the extracellular to intracellular compartment, increasing serum calcium, which may play a role in arterial disease. In some studies supplementation with calcium has been shown to decrease serum cholesterol. Absorption of calcium generally decreases with age, excess amounts of fat, protein, fiber intake, phosphorus (e.g. soft drinks), oxalates (e.g. leafy greens), and phytates (e.g. grains and legumes). Magnesium and zinc compete with calcium for absorption, as does iron without concurrent vitamin C administration. Good sources for dietary calcium includes sea vegetables, cheese, leafy greens (e.g. collards, turnip greens), almonds, sesame seeds and molasses. The optimal daily intake in adults is 800-1200 mg daily.

Magnesium

Magnesium is a macronutrient required in significant amounts and is involved in close to 300 different enzyme systems in the body. Magnesium is particularly concentrated in the myocardium where it plays a role in regulating the heartbeat, and acts to decrease coagulation, functions as a calcium-channel blocker, and relaxes smooth muscle in blood vessels. In postmortem studies of heart-attack victims it has been observed that myocardial concentrations of magnesium can be less than 42% of that in normal hearts. A deficiency of magnesium is associated with an increased risk of cardiac arrhythmia, coronary artery disease, and myocardial infarction. Supplementation of magnesium may prevent calcification of blood vessels and inhibit arterial disease. High intake of calcium, vitamin D, alcohol, phosphates, sugar, and sodium as well as thiazide diuretics all increase the need for magnesium. Good sources for dietary magnesium include sea vegetables, leafy green vegetables, nuts and seeds, whole grains, avocado, dried apricot and molasses. The optimal daily intake in adults is 300-800 mg daily.

Iron

Iron is an important macronutrient required in significant amounts and most importantly is a component of hemoglobin and myoglobin (the form of hemoglobin stored in the myocardium), used to transport oxygen to the tissues. A deficiency of iron is the most common cause of anemia, and may also play a role in cardiovascular disease. Vitamin C and stomach acid play an important role in iron absorption, especially from non-heme (i.e. non-animal) sources. Phosphates, oxalates, phytates, tannins, vitamin E and very high levels of calcium and zinc impair iron absorption. Good sources for dietary iron includes sea vegetables, leafy greens, brewer’s yeast, molasses, pumpkin and sesame seeds, red meat, eggs and dried prunes. The optimal daily intake in adults is 15-20 mg.

Zinc

Zinc is a macronutrient that plays a number of important roles, in hepatic detoxification, as a co-factor in energy production, in bone growth and maintenance, and in the activity of insulin. It is a co-factor in vitamin A absorption, assisting in supporting vision as well as the health of the skin and wound-healing. Zinc is a cofactor in protein digestion, in the synthesis of nucleic acids, and as part of the antioxidant superoxide dismutase that scavenges free radicals. Zinc is also a key player in immune function, used by the thymus gland to manufacture thymulin, which promotes T-cell differentiation and enhancement of T and natural killer cell activity. Zinc is also well-established as the ‘sex’ mineral, as a key constituent of prostatic fluid in men, while helping to improve libido in both men and women. Zinc tends to boost thyroid function, and should be taken in a balanced ratio with copper, which inhibits thyroid activity: 10:1 in favor of zinc for men, and 5:1 for women. Good sources for dietary zinc include oysters, beef, lamb, pumpkin seeds, sesame seeds and leafy greens. The optimal daily intake for adults is 15-15 mg daily.

Iodine

Iodine is an essential micronutrient that is required for the synthesis of thyroxine, the hormone produced and secreted by the thyroid gland that regulates metabolic activity, including the production of energy (ATP). Iodine is actively taken up by the follicular cells of the thyroid gland, and under the influence of thyroid stimulating hormone (TSH), uses it and the amino acid tyrosine to form both T3 (triiodothyronine) and T4 (tetraiodothyronine). T3 and T4 are then bound to thyroid hormone-binding serum proteins for transport, and released to target virtually every body tissue to increase protein synthesis and oxygen consumption. Low levels of iodine lead to an increase in TSH and thyroid activity, but without secreting any thyroxine, TSH levels continue to be elevated, stimulating the thyroid to enlarge to form a goiter. Iodine deficiency during pregnancy and infancy may impair growth and neurodevelopment of the offspring and increase infant mortality. Iodine has an uneven geographical distribution, and is only found in coastal regions, and thus iodine deficiency is endemic to inland areas. As a result, public health authorities have mandated that iodine be added to table salt, containing on average about 76 mcg of iodine per gram of table salt. Given the high salt content in fast foods like French fries, it is estimated that many people are consuming up to three times the RDA for iodine. Research suggests that like low iodine, high levels of iodine in the diet can also disturb thyroid function, a factor that may explain the increasing incidence of thyroid disease in developed countries. Other arguments suggest that the recent introduction and ubiquitous presence of other halides in the environment, including chlorine, fluoride and bromine, displace iodine from the body leading to a net deficiency. The best sources of iodine are seafood, including fish and seaweed, and to increase the iodine content of garden soil kelp is recommended as a fertilizer. While blood tests can be used to detect iodine deficiency, some practitioners use Lugol’s iodine to test for deficiency, that when applied topically will temporarily stain the skin. A few drops are administered topically to an area that is normally clothed such as the foot, and if the iodine is absorbed within a 72 hour period an iodine deficiency may be present. While it is best to get iodine in food, the optimal daily intake for adults is 150-200 mcg daily.

Copper

Copper is a key trace mineral required in relatively small amounts, forming part of the cytochrome system for cell respiration. Copper also assists in the transport of iron and the formation of hemoglobin, and is an important component of collagen, the myelin sheath and elastin, the latter of which gives blood vessels their capacity to stretch with increases in pressure. Copper is an important component of super oxide dismutase, but can also act as a free-radical when found free in the plasma and not bound to ceruplasmin. A deficiency of copper is specifically associated with hypercholesterolemia and decreased HDL. Copper also tends to suppress thyroid function, and should be taken in balanced ratios with zinc: 1:5 for women, and 1:10 for men. Good sources of dietary copper include oysters, cacao beans, whole grains, molasses, organ meats and sesame seeds. The optimal daily intake in adults is 2-4 mg.

Chromium

Chromium is a key trace mineral required in relatively small amounts, and is a component of glucose tolerance factor (GTF), comprised of one chromium molecule in a trivalent state, two niacin molecules, and three amino acids (i.e. glycine, cysteine and glutamic acid). GTF functions to enhance the activities of insulin, improving the uptake of glucose at the cellular level. Chromium has also been shown to lower cholesterol levels and increase HDL. Due to conventional farming practices and the loss of topsoil, chromium has been shown to be deficient in as much as 90% of the U.S. population. Tissue levels of chromium tend to decline with age leading to an increased risk of certain diseases such as CVD and diabetes. Strenuous exercise, a diet high in carbohydrates, as well as trauma all increase the excretion and thus the need for adequate chromium supplementation. Good sources of dietary chromium include nutritional yeast, beef, liver, whole grains, cabbage, shellfish and potato skins. The optimal daily intake in adults is 200-300 mcg daily.

Selenium

Selenium is an important trace mineral required in fairly modest amounts, functioning primarily as a key component of glutathione peroxidase, and to convert T4 into the metabolically active T3. Selenium deficiencies are in large part a symptom of modern agricultural methods and environmental pollutants such as sulfur dioxide that leach selenium from the soil. Although selenium deficiencies appear to be ubiquitous they often have a geographical distribution that is correlated to local soil-selenium deficiencies, and a significant local increase in the risk of CVD. Selenium deficiency is associated with an increase in LDL cholesterol, platelet aggregation, an increase in the risk of stroke, and a poor prognosis following myocardial infarction. Good sources of dietary selenium include nutritional yeast, fish, leafy greens, whole grains, molasses and garlic. The optimal daily intake in adults is 100-250 mcg.