Magnesium - Many Health Benefits

Magnesium is the fourth most-abundant mineral in the human body,[ 1 ] and is essential for the hundreds of metabolic and hormonal reactions occurring daily.[ 2 ] It is generally known to be a component of bone formation (partnered with calcium), and is gaining more interest as a sleep aid due to its natural muscle relaxant properties.

However, this only scratches the surface of the many benefits of magnesium. It is necessary for normal nerve and muscle function, heart rhythm, and immune-system health.^{[ 1 ][ 3 ]} As such, magnesium plays a vital role in a wide range of health conditions—asthma, migraines, autism spectrum disorder, cardiovascular disease, diabetes, and even cancer—and, therefore, should be considered when treating certain chronic disorders.

The recommended daily amount (RDA) of magnesium is 320 mg/d for an adult woman (400 mg/d in pregnancy), and 420 mg/d for an adult man, though actual dietary intake of the mineral is often reported to be much lower.^{[ 2 ][ 4 ]} In Canada, the estimated daily intake of magnesium is only 200–300 mg/d.^{[ 2 ]} It has even been suggested that the RDA underestimates the amount of magnesium we need, and quantities of 500–750 mg/d are more ideal.^{[ 2 ]} Magnesium is found naturally in leafy greens (spinach, mustard greens, Swiss chard), legumes (black and navy beans), nuts and seeds (almond, sunflower, pumpkin, flax), fish (mackerel, halibut), and pure dark chocolate.^{[ 3 ][ 4 ][ 5 ]} As a supplement, magnesium is inexpensive, generally safe, and well tolerated at recommended dosages.^{[ 1 ]}

Since it is difficult to accurately assess magnesium levels through laboratory tests alone, a more comprehensive approach is to combine lab tests and clinical findings, such as lifestyle, medical history, symptoms, and improvement with supplementation.^{[ 2 ][ 5 ]} Common symptoms of magnesium deficiency are leg cramps or spasms, muscle twitching, hypertonic (tight) muscles, shortness of breath, wheezing or asthma, and constipation.^{[ 2 ]}

Low magnesium levels have been found in patients with metabolic syndrome, diabetes, osteoporosis, asthma, fibromyalgia, and depression, as well as in premenstrual women.^{[ 3 ]} A magnesium deficiency is made worse with excessive caffeine and alcohol intake, intense or prolonged exercise, chronic stress, intestinal malabsorption (as in Crohn’s disease, gluten intolerance, and intestinal surgery), and with certain medications (such as diuretics, antibiotics, antifungals, proton-pump inhibitors for acid reflux, and chemotherapy drugs).^{[ 2 ][ 3 ][ 5 ]}

Asthma ^{[ 1 ]}

Being a natural smooth-muscle relaxant, magnesium has a bronchodilator effect on the respiratory system. Studies have shown that dietary magnesium improves lung function, airway hyperactivity, and wheezing. Magnesium will also inhibit the inflammatory response by stabilizing T cells (immune cells) and suppressing mast-cell (histamine-releasing allergy cell) activity.

Migraines ^{[ 1 ]}

Research shows that supplemental magnesium can help prevent migraines by decreasing the frequency and duration of episodes. There are several mechanisms by which magnesium does this. Firstly, it has a relaxant effect on blood vessels, thereby counteracting the vasoconstriction that can precede a migraine. Secondly, magnesium inhibits the creation of nitric oxide in the body, a substance that is activated early in the cascade of events leading to an episode. Thirdly, magnesium will counteract the release of substance P, which causes cerebral blood-vessel constriction during a migraine.

Autism Spectrum Disorder (ASD) ^{[ 6 ]}

Over the past 20 years, diagnosis of autism spectrum disorder (ASD) has risen rapidly at a rate that cannot be explained by improved diagnosis alone. Risk factors for ASD include prenatal exposure to certain viruses (rubella, cytomegalovirus), advanced maternal and paternal age at conception, and genetics. Individuals with ASD have serotonin and dopamine imbalances (anxiety, depression), less GABA (inhibitory) proteins, proinflammatory and free-radical production in the gut and brain, increased gastrointestinal permeability (food allergy, intolerances), and atopy (hay fever, asthma, eczema, allergic rhinitis). In addition, comorbid conditions are very common, such as sleep disorders and attention deficit-hyperactivity disorder (ADHD).

In children with ASD, there seems to be a low level of magnesium in the red blood cells. A 2006 study revealed that 70% of children with ASD had significant improvement with supplemental magnesium (at 6 mg/kg/d) plus vitamin B6. Magnesium could also treat ASD comorbid conditions, such as anxiety, depression, allergy, and sleep disturbances.

High Blood Pressure ^{[ 1 ]}

High blood pressure, or hypertension, is diagnosed at several readings over time, greater than 130/80 mmHg. Magnesium helps to dilate blood vessels by inhibiting the vasoconstriction activity of the sympathetic nervous system (our “fight-or-flight” response). It also keeps calcium absorption in check, thereby preventing calcium-related narrowing of blood vessels. A magnesium deficiency can lead to an increase in systemic inflammation, which can cause a rise in blood pressure. Studies show that supplementation with magnesium, in as low a dose as 240 mg/d, is effective at lowering blood pressure in patients on antihypertensive medications. For individuals not yet on any blood pressure medication, a higher dose of 480 mg/d (or more) is needed for positive results.

High Cholesterol ^{[ 2 ]}

Most individuals diagnosed with high cholesterol levels will be prescribed a statin drug, such as Lipitor. Statins work by blocking HMG CoA reductase, the enzyme that controls cholesterol production in the body. The problem is that statin drugs will also halt the cholesterol production that is required for cell-membrane synthesis and repair, hormone production, and converting sunlight into vitamin D. Magnesium can regulate HMG CoA reductase, switching it on and off as needed by the body. Plus, with its anti-inflammatory properties, magnesium provides protection against oxidative stress, which can lead to atherosclerosis—the buildup of fatty deposits (or plaques) along blood vessel walls.

Cardiovascular Disease ^{[ 2 ]}

Cardiovascular diseases encompass all conditions that arise from heart and blood-vessel issues, such as heart attack, stroke, heart failure, arrhythmia, and heart-valve problems. Many of these health conditions are related to hypertension and atherosclerosis. Magnesium helps to prevent excess calcium from being absorbed by the body, thereby reducing calcification of arteries. Adequate magnesium levels can also positively impact blood pressure and cholesterol levels. Commonly prescribed drugs for cardiovascular disease, such as loop and thiazide diuretics, can deplete magnesium and thereby further worsen the condition. As such, it is vital to add magnesium to a cardiac patient’s treatment plan, even more so when he or she is also taking a pharmaceutical prescription for the condition.

Coronary Heart Disease ^{[ 1 ]}

Coronary heart disease is a result of atherosclerosis in the arteries that supply oxygen-rich blood to the heart. Deficiencies in necessary nutrients may contribute to susceptibility to a heart condition. Magnesium should be considered a preventative treatment for ischemic heart disease and atherosclerosis. Magnesium is an integral part of energy production in heart muscle, maintaining regular heartbeat and promoting vasodilation to prevent vasospasm, or contraction, of heart vessels. Supplementation with magnesium can improve function in heart-failure patients, reduce the risk of coronary heart disease, and increase exercise stamina. One study that followed patients over a ten-year period found that those eating magnesium-rich diets had fewer cardiac complications, such as ischemic heart disease, arrhythmias, and angina. They also had lower mortality rates and fewer sudden deaths.

Type 2 Diabetes ^{[ 1 ][ 5 ]}

Low magnesium levels are common in patients with type 2 diabetes. Magnesium plays an important role in glucose metabolism, by influencing the release and activity of insulin. Studies have shown that magnesium supplementation improves insulin sensitivity, with long-term supplementation (300 mg/d for more than five years) promoting normal magnesium levels and alleviating diabetes-associated polyneuropathy. Furthermore, there is an association between magnesium deficiency in childhood and insulin resistance; thus, ensuring adequate magnesium levels may help prevent type 2 diabetes in children who are overweight. Low levels of magnesium in type 2 diabetes are an indicator of poor glycemic control. Less insulin is released from the pancreas, leading to increased insulin resistance. This can further increase magnesium excretion, thereby promoting a vicious cycle of poor metabolic control and greater risk of diabetes-related complications.

Cancer ^{[ 4 ]}

Studies show that a higher dietary magnesium intake seems to protect against cancer, particularly colorectal cancer and in females. Impaired DNA regulation and greater oxidative stress are contributing factors in cancer. Magnesium has a part in building and repairing DNA, regulating cell production and apoptosis (cell death), and defending against oxidative stress. Insulin resistance also increases the risk of developing cancer, and magnesium combats this by promoting glucose metabolism and insulin sensitivity. Magnesium may be a simple adjunct therapy to many complicated health conditions. Discuss with your health-care provider on how to best incorporate magnesium into your individualized treatment plan.