February 12, 2014

Use of Serum Magnesium Measurements to Exclude Magnesium Deficiency is Cause for Concern

Magnesium deficiency was found to be associated with increased prevalence and risk in 11 major health conditions. In 68 of the 183 peer-reviewed studies, magnesium deficiency was found to predict adverse events, and a decreased risk of pathology was noted when supplementation or treatment was instituted.


Ismail Y, Ismail AA, Ismail AA. The underestimated problem of using serum magnesium measurements to exclude magnesium deficiency in adults; a health warning is needed for “normal” results. Clin Chem Lab Med. 2010;48(3):323-327.


Analysis of peer-reviewed articles on magnesium published between 1990 and 2008. Using MEDLINE and EMBASE, the database keywords magnesium, deficiency, diagnosis, treatment, and hypomagnesaemia were searched. The bibliographies of retrieved articles were also searched.

Number of Studies

183 peer-reviewed studies published

Key Findings

Magnesium deficiency was found to be associated with increased prevalence and risk in 11 major health conditions. In 68 of the reviewed studies, magnesium deficiency was found to predict adverse events, and a decreased risk of pathology was noted when supplementation or treatment was instituted.

Practice Implications

This is one of the most important magnesium papers you will ever read. It speaks to the problem of obtaining accurate measurement of magnesium. Ismail et al acknowledge that serum magnesium is used in clinical practice to identify patients with deficiency. They also note that numerous studies have shown that magnesium deficiency is common and may be present in more than 10% of hospitalized patients, as well as in the general population. They found that magnesium deficiency was not diagnosed even at the 10 percent level in the papers they reviewed.
I agree that those figures are very low when the following points are taken into consideration:
  • There has been a gradual decline of dietary magnesium in the United States, from a high of 500 mg/day at the turn of the century to barely 175–225 mg/day today.1
  • The National Academy of Sciences has determined that most American men obtain about 80 percent of the recommended daily allowance (RDA) and women average only 70 percent.2
  • Most magnesium researchers find that the RDA is inadequate to prevent magnesium deficiency, making the above statistics of even more concern.3,4,5
Ismail et al found that serum magnesium is a very limited test because magnesium can be normal despite negative body stores. Unfortunately a so-called “normal” serum magnesium is usually never questioned. Usually only abnormal results flagged by the lab are even viewed by the doctor. Ismail et al suggest “a health warning is warranted regarding potential misuse of ‘normal’ serum magnesium because restoration of magnesium stores in deficient patients is simple, tolerable, inexpensive, and can be clinically beneficial.”
Usually only abnormal results flagged by the lab are even viewed by the doctor.
Ionized magnesium testing is the only viable method of diagnosing magnesium deficiency and following magnesium repletion therapy. It is presently used as a research tool. Mildred Seelig, MD, in an editorial she wrote in 1997, stated: “Now that clinically available means to determine ionic magnesium levels are more widely available, the substantial knowledge of the importance of diagnosing magnesium deficiency in patients, determining the effects of drugs that affect its levels, and ascertaining success in its repletion should be increasingly applied to patient care.”6
In the 13 years since Seelig wrote this paper, ionized magnesium testing still has not been made readily available to the public. Ionized calcium testing exists and is used widely, but until ionized magnesium testing is given equal status, we must ensure that clinical assessment of magnesium deficiency is more widely accepted.
Ismail et al also suggest clinical assessment of a patient’s risk for negative body magnesium stores. Magnesium deficiency is involved in all the below-listed conditions and functions.7
  1. Anxiety and panic attacks. Magnesium normally helps keep adrenal stress hormones under control.
  2. Asthma. Both histamine production and bronchial spasms increase with magnesium deficiency.
  3. Blood clots. Magnesium has an important role to play in preventing blood clots and keeping the blood thin—without any side effects.
  4. Bowel disease. Magnesium deficiency slows down the bowel, causing constipation, which could lead to toxicity and malabsorption of nutrients as well as colitis.
  5. Cystitis. Bladder spasms are worsened by magnesium deficiency.
  6. Depression. Serotonin, which elevates mood, is dependent on magnesium. A magnesium-deficient brain is also more susceptible to allergens, foreign substances that in rare instances can cause symptoms similar to mental illness.
  7. Detoxification. Magnesium is crucial for the removal of toxic substances and heavy metals such as aluminum and lead from the body.
  8. Diabetes. Magnesium enhances insulin secretion, facilitating sugar metabolism. Without magnesium, insulin is not able to transfer glucose into cells. Glucose and insulin build up in the blood, causing various types of tissue damage.
  9. Fatigue. Magnesium-deficient patients commonly experience fatigue because dozens of enzyme systems are underfunctioning. An early symptom of magnesium deficiency is fatigue.
  10. Heart disease. Magnesium deficiency is common in people with heart disease. Magnesium is administered in hospitals for acute myocardial infarction and cardiac arrhythmia. Like any other muscle, the heart requires magnesium. Magnesium is also used to treat angina, or chest pain.
  11. Hypertension. With insufïcient magnesium, blood vessels may go into spasm and cholesterol may rise, both of which lead to blood pressure problems.
  12. Hypoglycemia. Magnesium keeps insulin under control; without magnesium, episodes of low blood sugar can result.
  13. Insomnia. Sleep-regulating melatonin production is disturbed without suficient magnesium.
  14. Kidney disease. Magnesium deficiency contributes to atherosclerotic kidney failure. Magnesium deficiency creates abnormal lipid levels and worsening blood sugar control in kidney transplant patients.
  15. Migraine. Serotonin balance is magnesium-dependent. Deficiency of serotonin can result in migraine headaches and depression.
  16. Musculoskeletal conditions. Fibrositis, fibromyalgia, muscle spasms, eye twitches, cramps, and chronic neck and back pain may be caused by magnesium deficiency and can be relieved with magnesium supplements.
  17. Nerve problems. Magnesium alleviates peripheral nerve disturbances throughout the body, such as headaches, muscle contractions, gastrointestinal spasms, and calf, foot, and toe cramps. It is also used in treating the central nervous system symptoms of vertigo and confusion.
  18. bstetrical and gynecological problems. Magnesium helps prevent premenstrual syndrome and dysmenorrhea (cramping pain during menses), is important in the treatment of infertility, and alleviates premature contractions, preeclampsia, and eclampsia in pregnancy. Intravenous magnesium is given in obstetrical wards for pregnancy-induced hypertension and to lessen the risk of cerebral palsy and sudden infant death syndrome (SIDS). Magnesium should be a required supplement for pregnant women.
  19. Osteoporosis. Use of calcium with vitamin D to enhance calcium absorption without a balancing amount of magnesium causes further magnesium deficiency, which triggers a cascade of events leading to bone loss.
  20. Raynaud’s syndrome. Magnesium helps relax the spastic blood vessels that cause pain and numbness of the fingers.
  21. Tooth decay. Magnesium deficiency causes an unhealthy balance of phosphorus and calcium in saliva, which damages teeth.
In the Magnesium Miracle, I tackled the question of who is deficient in magnesium. The following 100 factors in 68 categories can help you recognize magnesium deficiency. There’s no way of knowing how many factors correlate with any one patient’s magnesium deficiency, but if you and your patients ticking off a few dozen, you may want to recommend magnesium supplements.
  • Alcohol intake (more than 7 drinks per week)
  • Anger
  • Angina
  • Anxiety
  • Apathy
  • Arrhythmia of the heart
  • Asthma
  • Blood tests indicating:
  • Low calcium,
  • Low potassium, or
  • Low magnesium
  • Bowel problems
  • Undigested fat in stool
  • Constipation
  • Diarrhea
  • Alternating constipation and diarrhea
  • Irritable bowl syndrome
  • Crohn’s disease
  • Colitis
  • Brain trauma
  • Bronchitis, chronic
  • Caffeine (eg, coffee, tea, chocolate), more than three servings per day
  • Chronic fatigue syndrome
  • Cold extremities
  • Concentration difficulties
  • Confusion
  • Convulsions
  • Depression
  • Diabetes
  • Type I
  • Type II
  • Gestational diabetes
  • Fibromyalgia
  • Food intake imbalances
  • Limited green leafy vegetables, seeds, and fresh fruit
  • High protein
  • Food cravings
  • Carbohydrates
  • Chocolate
  • Salt
  • Junk food
  • Gagging or choking on food
  • Headaches
  • Heart disease
  • Heart, rapid rate
  • High blood pressure
  • Homocysteinuria
  • Hyperactivity
  • Hyperventilation
  • Infertility
  • Insomnia
  • Irritability
  • Kidney stones
  • Medications
  • Digitalis
  • Diuretics
  • Antibiotics
  • Steroids
  • Oral contraceptives
  • Indomethacin
  • Cisplatin
  • Amphotericin B
  • Cholestyramine
  • Synthetic estrogens
  • Memory impairment
  • Mercury amalgam dental fillings
  • Menstrual pain and cramps
  • Migraines
  • Mineral supplements
  • Take calcium without magnesium
  • Take zinc without magnesium
  • Take iron without magnesium
  • Mitral valve prolapse
  • Muscle cramps or spasms
  • Muscle twitching or tics
  • Muscle weakness
  • Numbness of hands or feet
  • Osteoporosis
  • aranoia
  • Parathyroid hyperactivity
  • Premenstrual syndrome
  • Polycystic ovarian disease
  • Pregnancy
  • Currently pregnant
  • Pregnant within 1 year
  • History of preeclampsia or eclampsia
  • Postpartum depression
  • Have a child with cerebral palsy
  • Radiation therapy, recent
  • Raynaud’s syndrome
  • Restlessness
  • Sexual energy diminished
  • Shortness of breath
  • Smoking
  • Startled easily by noise
  • Stressful life or circumstances
  • Stroke
  • Sugar, high intake daily
  • Syndrome X
  • Thyroid hyperactivity
  • Tingling of hands or feet
  • Transplants
  • Kidney
  • Liver
  • Tremor of the hands
  • Water that contains the following
  • Fluoride
  • Chlorine
  • Calcium
  • Wheezing
In all my research on magnesium, I find it one of the safest supplements used in clinical practice. It does not build up in the tissues like calcium. If a person takes too much, a laxative effect occurs and the excess is eliminated.
If one experiences the laxative effect with the most common form of magnesium (magnesium citrate) before reaching a therapeutic effect of magnesium, various other forms of magnesium, including magnesium oil and angstrom-size magnesium, may be used. More research should be forthcoming on these 2 developments in the field magnesium supplementation.

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  1.  Altura BM. Introduction: importance of Mg in physiology and medicine and the need for ion selective electrodes. Scand J Clin Lab Invest Suppl. 1994;217:5-9.
  2.  Dietary Reference Intake for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Institute of Medicine. Washington, DC: National Academy Press; 1997.
  3.  Durlach J. Magnesium in Clinical Practice. London: Libbey; 1988.
  4.  Fehlinger R. Therapy with magnesium salts in neurological diseases. Magnes Bull. 1990;12:35-42.
  5.  Ducroix T. L’enfant spasmophile—Aspects diagnostiques et thérapeutiques. Magnes Bull. 1984;1:9-15.
  6.  SeeligM. How best to determine magnesium status; a new laboratory test worth trying. Nutr Intl J Appl & Basic Nutr Sci. 1997;13:376-377.
  7.  Dean C. Magnesium Miracle. New York: Ballantine Books; 2007