ESSENTIAL TRACE ELEMENTS PREPARED BY B.KIRUTHIGA LECTURER DEPT OF PHARMACEUTICAL CHEMISTRY

ESSENTIAL TRACE ELEMENTS PREPARED BY B.KIRUTHIGA LECTURER DEPT OF PHARMACEUTICAL CHEMISTRY

Back to Basics: Elements Remember that all matter is made of elements An element is a substance in its simplest form (an element cannot be separated into simpler substances) For example, the mineral calcite can be broken down to calcium, carbon and oxygen, but these constituent elements can t be broken down any further (at least at the atomic level) There are over 100 elements, of which 92 occur in nature An atoms of a particular element has a unique number of protons and electrons (number of neutrons can vary, hence the designation of isotopes)

Abundance of Elements Different elements occur in different concentrations in the Earth system We can classify elements on the basis of concentration in nature. For uncommon elements (minor and trace), we usually cite abundance in ppm (parts per million). I part per million would be the equivalent of 1 milligram per 1 kilogram. Major elements: >10,000ppm (or about 1% by volume) Minor elements: 1,000-10,000ppm Trace elements:<1,000ppm on average

Concentration of Elements in the Body Certain tissues of the body accumulate certain elements in higher concentrations, partly due to the role of tissues in the functioning of the human body. For example, fluorine (as fluoride) is incorporated into bones and teeth, so health consequences of variations in concentrations are most likely to be noticed in these tissues. Also, strontium can substitute for calcium in bones, so would be expected to affect bone health. Likewise, the thyroid gland uses iodine to make hormones, so variations in iodine concentration would be expected to be most apparent in the thyroid gland.

Elements in the Earth and in Our Bodies Trace elements are somewhat of a different matter. We have evolved to cope with extremely small quantities of these (and to use some for biological processes). But slight variations in the abundance of trace elements in our bodies can have profound effects on health. To assess the effects of trace element concentrations on human health, we talk about dose response. Dose response can be depicted in different ways (as we will see), but basically refers to the health response to different doses of a particular substance.

Importance of Element Concentrations Certain concentrations of elements in our bodies are essential to normal functioning A common misconception is that elements such fluorine, known to be beneficial to dental health in certain concentrations, should be more beneficial in high quantities. But this is not so- too little is bad, but too much can be worse. Deficiency or excess of various elements in our bodies is largely controlled by geological factors- whether they be in the direct vicinity of an individual or in the place where food or water are derived (if imported).

Universally Harmful Trace Elements Some trace elements are not beneficial to life processes in any concentration. These include: Arsenic negative effects on functioning of heart Cadmium negative effects on kidneys and skeletal growth Lead negative effects on kidneys, fertility, nervous system and heart Mercury negative effects on nervous system and fertility Aluminum negative effects on nervous system and skeleton

Universally Harmful Trace Elements At extremely low concentrations, these elements are benign (no effect) At slightly elevated concentrations (above a threshold), these elements cause harm But at no levels are these beneficial

Essential Trace Elements Essential trace elements are those elements that are essential for biological processes in low concentrations. These include: Chromium plays part in metabolism of sugar Cobalt part of vitamin B-12 Copper involved in metabolism, production of hemoglobin Fluorine gives strength to bones and teeth Iodine used in production of thyroid hormones Iron essential component of hemoglobin Manganese involved in bone growth and metabolism Selenium reduces aging action of free radicals Zinc important for body growth, and plays part in immune system Note: these are but a few examples of how these elements are used (many have several more functions than indicated)

Optimal dose This is a schematic view of how different doses of a particular element can affect human health Very low doses can produce adverse health effects Very high doses can also produce adverse health effects The key is somewhere in the middle (the Goldilocks principle)

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