Trace minerals are micro-nutrients that are required in very small or “trace” amounts, generally less than 20 mg (milligrams) per day. There are several trace minerals that are necessary for regular intake, including iron, iodine, selenium, and zinc. Since trace minerals are needed in trace quantities, it is relatively easy to have sufficient intake, as long as we eat mostly healthy. Therefore, trace mineral deficiencies are not very common, particularly if you eat a well rounded diet.
In contrast to trace minerals, “essential minerals” are needed by our bodies in relatively large amounts, and these are also referred to as macro-minerals. It is relatively difficult to achieve a consistently good intake of some essential minerals such as calcium, magnesium and potassium. In particular, dietary deficiencies of calcium and magnesium are quite common. There are several reasons for this, such as relatively inefficient absorption of calcium and magnesium from solid foods (particularly as we age, and stomach acid production decreases), relatively high consumption of processed or refined foods (these usually do not have a good or balanced proportion of essential macro-minerals), lots of people eating specialized, restricted, or weight-loss diets etc. Further, many prescription medicines when taken regularly have side effects of causing nutrient depletion.
It is also important to note that many published scientific studies have shown that drinking water with healthy levels of calcium and magnesium electrolytes is beneficial, particularly for cardiovascular health.