The causes of a lack of magnesium can include dietary choices, availability of foods high in magnesium, as well as illness, use of certain pharmaceuticals, and genetic factors.
Low magnesium can be hard to detect, so the first step to preventing magnesium deficiency is knowing its risk factors.
Magnesium Deficiency Causes
Magnesium depletion in healthy individuals can be caused by:
- Low magnesium diets, processed foods and sodas
- Soft water
- Calcium supplements
- Prescription and over the counter medications
And some conditions can increase vulnerability to deficiency, including:
A magnesium poor diet in America is the norm, not the exception.
The average American diet supplies less than two thirds of the magnesium required by the body. 1 2 Yet each person is individual, not only in their intake of magnesium, but also in their ability to absorb and utilize this key mineral.
Depletion of Magnesium in the Diet
The typical American diet, which is rich in fat, sugar, salt, synthetic vitamin D, phosphates, protein, and supplemented calcium, not only is deficient in magnesium but actually increases the need for magnesium in the body.” 3
Magnesium-rich foods include whole grains, leafy greens, nuts and seeds. Foods like these were once common in diets around the world, but an increase in both food processing and the availability of enticing convenience foods with added fats and sugars has had its impact. Whole and unrefined foods high in magnesium are becoming increasingly rare in the modern diet.
The question of what causes low magnesium is in some ways easy to answer when examining modern eating habits. A visit to the local supermarket finds cashiers unable to identify basic green vegetables such as kale, chard, and mustard greens, all high in magnesium.
It is not uncommon to find adults and children who state, “I don’t eat things that are green.” Fried foods such as chips and French fries have replaced healthy finger foods such as nuts and seeds. And millions around the world have entirely replaced their consumption of mineral-containing water with the consumption of carbonated beverages and coffee—drinks which actually reduce available magnesium through their high phosphate and sugar content and diuretic properties.
Each of these common eating habits compounds to create a general lack of magnesium in the diet. The consequences of the American diet on magnesium status are direct:
- A high-saturated fat diet reduces magnesium absorption in the intestines. 4 5
- High sugar intake increases excretion of magnesium by the kidneys. 6 7
- Phosphates found in carbonated beverages such as dark-colored sodas bind magnesium, rendering it unusable by the body.
Soft Water and Magnesium
In areas with high mineral water content, increased magnesium consumption has been shown to have positive effects on health. Similarly, soft water sources have been shown to reduce magnesium intake, and in some cases may contribute to magnesium deficiency. 8 9
A symposium held by the World Health Organization in 2009 brought together scientists and medical professionals to review scientific evidence for the impact of calcium and magnesium in drinking water. Magnesium and health experts examined whether water softening may be a factor in what causes magnesium deficiency throughout the world, and considered what recommendations should be made as to softening and/or supplementation of global water supplies.
The symposium made clear acknowledgement of the benefit of magnesium in drinking water to public health. Directly addressing heart health specifically, it was stated:
The studies do show a [protective effect] between cardiovascular mortality and drinking-water magnesium. Although this association does not necessarily demonstrate causality, it is consistent with the well known effects of magnesium on cardiovascular function.” 10
Water softening is often done to improve the household cleaning properties of water, yet doing so removes a valuable source of magnesium—one that can provide as much as 50% of the RDA in some parts of the world.
Increasingly, municipal water sources remove magnesium as a part of water treatment, though some municipal sources do re-supplement water supplies after softening. Depletion of magnesium at the source can be a significant factor in low magnesium status.
Experts advise:
- Contacting local government resources to determine the magnesium content of your water supply.
- Seeking a magnesium content of at least 10-30% of RDA per two liters (68 fluid oz.), or a minimum content of approximately 130 ppm or mg/L.
- Actively supplementing magnesium in cases where water magnesium content is low.
Excess Calcium and Magnesium
Magnesium deficiency’s causes can also include supplementation of other competing vitamins and nutrients. Today many people, especially women, supplement with calcium to prevent bone loss and osteoporosis.
Calcium cannot be effectively utilized or absorbed without adequate magnesium.
Yet widespread knowledge of the need for calcium is, unfortunately, not accompanied by a widespread knowledge of the need for magnesium. As a result, many are actively depleting their magnesium stores without realizing it—through their supplementation with calcium.
An overabundance of calcium increases the body’s need for magnesium. And calcium cannot be effectively utilized or absorbed without adequate magnesium.
It is commonly recommended to take calcium and magnesium supplements at a 2:1 ratio. However, according to several magnesium experts a 1:1 ratio (or even a ratio that favors magnesium) can sometimes be advisable, especially when certain conditions or illnesses or present, or when the diet is skewed excessively toward calcium intake, as is the case with many American diets. 11 12
Medications That Can Cause Magnesium Deficiency
Among the known magnesium deficiency causes are prescription medications such as diuretics, antibiotics, painkillers and cortisone, which can deplete magnesium levels in the body by impairing absorption or by increasing excretion by the kidneys.
Some specific medications that increase excretion of magnesium and/or increase the body’s magnesium requirements are:
- Certain antibiotics such as Garamycin, tobramycin (Nebcin), carbenicillin, ticaricillin, amphotericin B and antibiotics of the tetracycline class
- The anti-fungal drug Pentamidine, used to prevent and treat pneumonia
- Estrogen, found in birth control pills and hormone replacement therapy
- Corticosteroids such as hydrocortisone
- Diuretics such as Edercrin, Lasix, mannitol, and thiazides (with names commonly ending in -zide)
- Certain heart failure medications including digitalis, digoxin (Lanoxin), Qunidex, and Cordarone
- Medications used to treat irregular heartbeat, such as Cordarone (amiodarone), bretylium, quinidine (Cardioquin) and sotalol (Betapace)
- The anti-cancer drug Platinol, and other immunosuppressant drugs such as Neoral and Sandimmune
- Antineoplastics, used in chemotherapy, and radiation
- Asthma medications such as epinephrine, isoproterenol and aminophylline
- The antipsychotic and antischizophrenic drugs Pimozide (Orap), Mellaril and Stelazine 13
Addiction, Alcoholism and Magnesium Depletion
In cases of addiction or alcoholism, low intake and absorption can cause magnesium deficiency. Complications such as liver disease, vomiting and diarrhea reduce body levels of magnesium, and treatment of addiction may in fact further complicate issues when withdrawal is experienced. In some cases, intravenous magnesium replacement is warranted during severe alcohol withdrawal. 14
Illness, Stress and Aging as Causes of Low Magnesium
Stressful conditions require more magnesium by the body, thus those experiencing these conditions are more susceptible to magnesium deficiency. Examples include:
- Surgery
- Burns
- Liver disease
- Diabetes
- Hormonal imbalances
These conditions not only increase the body’s need for magnesium, but also may reduce stomach acid levels, reducing the body’s ability to break down foods and supplements into an absorbable form. Magnesium’s bioavailability is vulnerable to a reduction in hydrochloric acid, because many forms of magnesium must be broken down into an ionic form in the digestive tract to be used by the body.
The natural process of aging also reduces stomach acid levels and is associated with reduced absorption of magnesium.
Once broken down in the stomach, magnesium must be absorbed in the small intestine. The level of absorption is also known to be affected by an individual’s state of health, as well as the presence of other minerals such as iron and calcium, which can impede magnesium absorption.
Diseases of Magnesium Malabsorption and Depletion
Digestive disorders such as Crohn’s disease, genetic diseases and other conditions may cause magnesium wasting by the kidneys or problems with absorption. For such individuals, higher intakes of magnesium are required to replace amounts lost.
Some syndromes associated with problems of magnesium absorption include:
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Disorders such as these may be difficult to diagnose, though chronic deficiency symptoms such as muscle cramping, fatigue, irritability or high blood pressure may be an indication of magnesium depletion when accompanied by adequate dietary magnesium intake.
In addition, severe diabetic ketoacidosis may be a cause of hypomagnesemia. In these cases, extreme insulin deficiency leads to breakdown of compounds within the cells, releasing magnesium and excreting it from the body.
Know Your Risk Factors
Due to an inability to accurately test body magnesium content, it is unknown exactly how many Americans are currently magnesium deficient, nor how many persons are deficient worldwide.
Current tests focus on serum magnesium, which has been shown inadequate to pinpoint the existence or non-existence of a potential bodily deficiency. Since only 1% of bodily magnesium is stored in the blood, low blood magnesium cause and effect does not necessarily overlap magnesium deficiency cause and effect. Alternate magnesium tests do exist, such as challenge testing, load testing, and the more recent ExaTest, but these are less commonly adopted by health professionals.
Because of this difficulty in diagnosing magnesium deficiency, many doctors and health providers will consider not just test results and current symptoms, but also risk factors when addressing the possibility of magnesium deficiency.
For individuals considering their own magnesium status, the key is knowing both:
- The causes of magnesium deficiency (described on this page)
- The signs of magnesium deficiency, including tell-tale symptoms and conditions
By understanding the causes of a lack of magnesium, it’s possible for each of us to make proactive individual decisions on whether to supplement this commonly deficient essential mineral.
For persons without kidney disease, magnesium supplementation has no side effects other than loose stools when taken orally, indicating a need to reduce dosage. 15 And transdermal applications of magnesium avoid digestive problems entirely.