Mineral Deficiency Health Article

Selenium deficiency

Selenium deficiency may occur in premature infants who naturally tend to have about one-third the selenium levels of full-term infants. It is not known if these lower levels result in adverse consequences. Selenium deficiency occurs in regions of the world containing low-selenium soils, including parts of China, New Zealand, and Finland. In Keshan Province, China, a condition (Keshan disease) occurs that results in deterioration of regions of the heart and the development of fibers in these areas. Keshan disease, which may be fatal, is thought to result from a combination of selenium deficiency and a virus.

Zinc deficiency

Zinc deficiency can be caused by diarrhea, liver and kidney disease, alcoholism, diabetes, malabsorption, and overconsumption of fiber. Symptoms of zinc deficiency include acne, recurrent colds and flu, loss of senses of taste and smell, poor night vision, slow growth, lack of sexual maturation, lack of pubic hair, and small stature. Studies have shown that signs of zinc deficiency are detectable after two to five weeks of consuming a zinc-free diet. Signs include a rash on the face, groin, hands and feet, and diarrhea. Administering zinc will correct these symptoms.

When to call the doctor

Mineral deficiencies present with a wide variety of symptoms. Parents should observe children closely and report any unusual symptoms to the pediatrician, such as tiredness, weakness, depression or anxiety, irritability, nervousness, skin irritations, dehydration from vomiting or diarrhea, and slow growth or development of skills. Other than providing regular vitamin supplements and a balanced diet to prevent deficiencies, parents should not attempt to diagnose and treat deficiencies on their own.

Diagnosis

Individual minerals can be measured in blood serum, red blood cells, tissue cells, or urine, to estimate available levels and determine normal or abnormal status. Since each mineral performs strikingly different functions, tests to confirm deficiency are markedly different from each other. Testing can range from simple to extensive. Physicians will consider the possible consequences of each type of deficiency and evaluate the function of organ systems affected by the particular mineral.

In addition to determining serum calcium, phosphorus, and vitamin D levels, the diagnosis of calcium and phosphorus deficiency may involve taking x rays of the skeleton.

Diagnosing iron deficiency will require measuring iron levels and investigating anemia by performing blood tests such as a complete blood count (CBC) to determine the number of red blood cells, hemoglobin level, red cell volume, and cell maturity (morphology). A stair-stepping test may be used to evaluate stamina, but a blood test is required to diagnose iron deficiency.

Diagnosing low levels or imbalances of the electrolytes sodium, potassium, calcium, magnesium, or phosphate involves measuring the serum levels of each. Measurement determines the circulating blood level at the time blood was drawn. Laboratory values of sodium and potassium, which are present within cells and in the fluid between cells, can change rapidly depending on the individual's overall condition. They may be measured repeatedly to determine a trend and to monitor correction of the deficiency or imbalance after diagnosis.

Normal serum magnesium levels are 1.2–2.0 mE/l, while levels in deficiency (hypomagnesemia) are below 0.8 mE/l. Because calcium and magnesium must remain balanced, magnesium levels below 0.5 mE/l can provoke a decline in serum calcium levels. Hypomagnesemia can also result in low serum potassium. Symptoms of hypomagnesemia, such as twitching and convulsions, may actually result from the hypocalcemia. Other symptoms, such as cardiac arrhythmias, actually occur because of low potassium. All three minerals will be measured.

Iodine deficiency is diagnosed by measuring the concentration of iodine in urine. A urinary level greater than 0.05 mg iodine per gram of creatinine (another metabolite excreted in urine) indicates adequate iodine status. Levels under 0.025 mg iodine/gram creatinine indicate serious risk. The doctor may also examine the neck with the eyes and hands to see if a goiter is present.

Urinary zinc levels will differ between normal dietary intake (16 mg per day) and low-zinc diets (0.3 mg per day); normal urinary zinc is about 0.45 mg per day while low-zinc urinary levels are about 0.150 mg per day. Plasma zinc levels tend to be maintained during a dietary deficiency in zinc. Plasma and urinary zinc levels can be influenced by a variety of factors, and for this reason cannot provide a clear picture of zinc status.

Selenium can be measured in plasma or red blood cells and compared to normal values. The activity of an enzyme (glutathione peroxidase) in platelets (small blood cells essential in blood clotting) may be evaluated to assess selenium status.