Food sources
Magnesium is found in a wide variety of foods, usually in small amounts. Good sources of magnesium include whole grains, nuts, beans, tofu, and dark green vegetables. Meat, fish, and dairy products also provide significant amounts.

Health applications

• Cardiovascular health
• Bone Strength/development
• Diabetes
• PMS
• Alcoholism
• Hearing and vision
• Muscle and nerve function
• Hyperactivity/attention deficit disorder
• Migraine headaches
• Fatigue

Deficiency symptoms
Symptoms of magnesium deficiency include disorientation, confusion, depression, loss of appetite, fatigue, tingling, numbness, muscle spasms and cramps, abnormal heart rhythms, and seizures. Low magnesium levels have also been linked to heart disease, hypertension, and PMS. When magnesium deficiency occurs, it is usually due to excessive loss of magnesium in urine, gastrointestinal disorders that limit absorption, or chronically low magnesium intake. Magnesium deficiency is most common in the elderly, alcoholics, and people with poorly controlled diabetes.

Bone strength/development
Magnesium plays a crucial role in the strength and development of bones. About half of the magnesium in the human body is combined with calcium and phosphorus in bone tissues. Magnesium depletion has been implicated in the development of osteoporosis, and studies suggest that magnesium supplements may help reduce bone loss and increase bone density.^1,2

Cardiovascular health
Magnesium is a vital mineral for healthy heart and cardiovascular function. Insufficient magnesium levels in the body have been linked to heart failure, arrhythmia, hypertension, and stroke.^3-6 Studies have shown that improving magnesium status in patients with heart disease can improve heart function and reduce the incidence of arrhythmia, heart failure, and mortality.^7-9 Although magnesium's role in cardiovascular function is not fully understood, the mineral appears to influence a number of factors. Magnesium inhibits the clumping together of blood platelets, which can reduce the tendency of blood to form clots that block blood vessels.^10,11 As an electrolyte, magnesium helps maintain the balance of minerals required for the heart and all muscles to function efficiently.

Diabetes
Magnesium appears to play an important role in the development and progression of diabetes. Low magnesium status has been associated with the development of both type I and type II diabetes,^12-17 and has also been linked to pregnancy complications commonly seen in diabetics.¹⁸ Although preliminary research indicates that magnesium supplementation can improve insulin response in patients with noninsulin-dependent-diabetes-mellitus (NIDDM),^19,20 further studies are needed before the potential of magnesium in diabetes treatment can be determined.

Premenstrual syndrome
A number of studies have linked magnesium deficiency to the development of premenstrual syndrome (PMS).^21-24 Compared to healthy controls, women with PMS were found to have significantly lower levels of magnesium in their red blood cells.^21,22 In one study, the plasma magnesium levels of PMS sufferers were shown to be lower during times when the women were experiencing symptoms than in asymptomatic times.²⁴ The results from placebo-controlled trials suggest that magnesium supplementation may help reduce some PMS symptoms, including mood changes and fluid retention.^25-26

Migraine headaches
There is significant evidence that magnesium deficiency may play a role in migraine headaches. Numerous studies have found lower concentrations of magnesium in the red blood cells of migraine patients than in samples from healthy controls.^27-30 One study observed low serum and saliva magnesium levels in migraine patients compared to healthy controls, with these levels lowest during migraine attacks.³¹ Preliminary trials indicate that supplemental magnesium may significantly reduce the incidence of migraine attacks.^32,33

Attention deficit/hyperactivity
Examinations of blood and hair samples indicate that magnesium deficiency is more common in children with attention deficit hyperactivity disorder (ADHD) than it is in healthy children. ^34,35 Significant decreases in hyperactivity have been observed in magnesium-deficient children given magnesium supplements.^35,36

Alcoholism
Chronic alcohol abusers have an increased risk of magnesium deficiency.^37-40 Alcoholism can deplete magnesium levels in a variety of ways, including malnutrition, increased urinary magnesium excretion, and reduced intestinal absorption.³⁷ Thus, magnesium supplementation is commonly recommended for recovering alcoholics. A study conducted on chronic alcoholics showed improvement in muscle strength, liver function, and electrolyte levels in subjects given magnesium supplements.⁴¹

Chronic fatigue/fibromyalgia
Fatigue is a common symptom of magnesium deficiency, and some research has linked magnesium deficiency to chronic fatigue syndrome (CFS).⁴² However, other studies found no link between CFS and magnesium status.⁴³ Low magnesium levels have also been implicated in fibromyalgia syndrome,⁴⁴ and a supplement combining magnesium and malic acid improved fibromyalgia symptoms in one study.⁴⁵

Hearing/vision
Magnesium appears to play an important role in both vision and hearing. Preliminary research suggests that magnesium may enhance peripheral circulation and improve the visual field in glaucoma patients.⁴⁶ Other studies indicate that magnesium supplements may help protect against noise-induced hearing loss.^47-49

Dosage/toxicity
The 1999 RDAs for magnesium:

Age range	Men	Women	Pregnancy	Lactation
14-18	410 mg/day	360 mg/day	400 mg/day	360 mg/day
19-30	400 mg/day	310 mg/day	350 mg/day	310mg/day
31+	420 mg/day	320 mg/day	360 mg/day	320 mg/day

Many people consuming the typical "Western" diet do not get the RDA for magnesium from their foods, and may be at risk for marginal deficiency. The elderly are at particular risk for magnesium deficiency, due to decreased absorption and other factors.^50,51 The recommended dose for magnesium supplements varies with the magnesium content of the diet. The amount of elemental magnesium in supplements varies depending on the form used.