Magnesium: The Vital Mineral for Good Health
The Biomarker Handbook is a curated series that seeks to provide readers with insights on each biomarker we cover in our blood test packages and its relation to our body.
Magnesium, is one of the most abundant electrolytes and a vital mineral in the human body. It is necessary for RNA and DNA synthesis, energy production, blood pressure regulation, insulin metabolism, and maintenance of strong bones.
Magnesium is also essential for the transport of potassium and calcium between cell membranes, which ensures that processes such as nerve transmission, muscular contraction, and cardiac rhythm, are maintained. Any abnormalities in magnesium level in our body can thus also affect calcium and potassium levels across cell membranes.
How Our Body Regulates Magnesium Levels
About 99% of the total body magnesium, is stored in muscles, soft-tissue, and bones. Only 1% of total body magnesium is in the blood, so blood tests do not reflect accurately our body magnesium levels. However it is still useful and the best method available for magnesium measurement in our body.
Physiologically, body magnesium levels are regulated by the amount we absorb from the bowels and also the amount we excrete and reabsorb in the urine. Any excess or deficiency of magnesium is counteracted by adjusting the amount of magnesium we absorb in our bowels, and also the amount of magnesium we reabsorb and thus excrete in our urine. This keeps the magnesium in our body within a tight range when healthy. In healthy adults, serum magnesium concentrations range from 0.76 to 1.15 mmol/L (1.7 to 2.3 mg/dL).
Apart from blood magnesium, your doctor may also use a 24-hour urine magnesium level to see if there is excess magnesium in the urine to explain low blood magnesium, or as a result of high blood magnesium.
Signs and Symptoms of Magnesium Imbalance
Magnesium deficiency (hypomagnesemia) or excess (hypermagnesemia), though uncommon, can have adverse consequences to your health and need medical care. Hypo- and hypermagnesemia can produce few to no symptoms if its mild to moderate. If the abnormality in magnesium levels persists in time or if it becomes severe, symptoms like tremors, nausea, hyporexia or anorexia, confusion, dizziness, fatigue, muscle cramps, cardiac arrhythmias (palpitations), seizures, or coma can occur.
Hypomagnesemia occurs when there is reduced absorption from the bowels, increased excretion in the urine, and reduced re-absorption in the urine. Conditions that can cause malnutrition, excessive renal excretion, or gastrointestinal malabsorption can potentially lead to hypomagnesemia. Examples of these conditions include chronic diarrhea, alcoholism, malabsorption, and chronic stress.
Hypomagnesemia has been associated to diseases such as osteoporosis, type 2 diabetes mellitus, insulin resistance, pulmonary disease, hypertension, attention deficit hyperactivity disorder, depression, migraine headaches, Alzheimer’s disease, and cardiovascular disease. Therefore, magnesium levels can help diagnose the severity of kidney disorders, diabetes, and several gastrointestinal conditions.
On the other hand, hypermagnesemia occurs when there is excessive digestive absorption or defective urinary excretion of magnesium. These can be seen in over-ingestion of antacids or laxatives that contain magnesium, in pregnant women receiving magnesium sulfate as an anticonvulsant for severe preeclampsia or eclampsia, and in severe kidney disease.
Ways to Balance Magnesium Levels
Magnesium is available in oral supplements. In cases of hypomagnesemia with mild or no symptoms, magnesium can be given orally. In severe cases of hypomagnesemia, or as part of the treatment for preeclampsia, intravenous magnesium sulfate is used.
Magnesium can be found in many foods and beverages, including green vegetables, legumes, whole grains, fruits, seeds, nuts, fish, meat, milk, and tap water. Magnesium is usually also added to bottled water and fortified foods like breakfast cereals.
Our daily recommended magnesium intake for healthy adult women is 300mg, and 400mg for men. Supplements are available in a variety of presentations such as magnesium citrate, magnesium chloride, magnesium oxide, magnesium lactate, and magnesium orotate. On average 30% to 40% of the consumed magnesium is absorbed by the body.
Hypermagnesemia treatment usually consists of withdrawing the source of magnesium, along with calcium supplementation, diuretics, and in some cases, hemodialysis. And just like all cases of hypomagnesemia, managing the underlying disease causing the hypo- or hypermagnesemia is also necessary.
Tracking your magnesium levels regularly to monitor treatment efficiency is necessary. If treatment is hospital administered, your doctor may monitor the levels daily. If symptoms are mild and treatment is through oral supplements, your doctor may check your magnesium levels after 2 to 4 weeks of starting treatment.
When Should You Track Your Magnesium Biomarker?
Magnesium screening is not usually indicated in all individuals, and is often not ordered alone, but rather with other electrolytes such as sodium, calcium, potassium, bicarbonate, phosphorus, and chloride. There is a close correlation between magnesium deficiency and changes in these other electrolytes, especially calcium and potassium.
Magnesium is ordered when a person is presenting signs and symptoms that are suggestive of hypo- or hypermagnesemia. It can also be ordered when a blood panel shows unexplained hypocalcemia (low calcium levels), and in cases where hypokalemia (low potassium levels) is unresponsive to potassium supplements.
Other indications for magnesium screening include individuals who have cardiac disorders that can prove to be fatal in case of developing hypomagnesemia, individuals who are taking high-dose diuretics, pregnant women with severe preeclampsia or eclampsia who are receiving magnesium sulfate as an anticonvulsant, and individuals with uncontrolled diabetes or kidney disorders.
Magnesium is one of the main electrolytes present in the body, its closely correlated to other electrolytes such as sodium, potassium, and calcium. Therefore, it shouldn’t be screened alone, but rather taking into consideration all other electrolyte parameters and the individual’s clinical situation.
Serum magnesium concentration is the most commonly used test to assess the amount of body magnesium. However, it has its limitations due to the distribution of magnesium in the body (only 1% of the body’s total magnesium is located extracellularly in the blood).
The onset of hypomagnesemia, or less frequently, hypermagnesemia, can prove fatal if left untreated. A great variety of foods contain magnesium, and healthy individuals with normal kidney function should be capable of maintaining normal levels of this electrolyte by having a balanced diet.
Symptoms from hypo- and hypermagnesemia usually occur when severe, so track your levels to know before it becomes severe.
If you want to learn more about magnesium as a biomarker and how you can maintain healthy magnesium levels, read more about it in our lifestyle post here!
Interested in other biomarkers? Check out the rest of The Biomarker Handbook.
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