Magnesium is an abundant mineral in the body, naturally present in many foods, added to other food products, available as a dietary supplement, and present in some medicines (such as antacids and laxatives).

It is a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation.

Also, it is required for energy production, oxidative phosphorylation, and glycolysis. 

It contributes to the structural development of bone and is required for the synthesis of DNA, RNA, and the antioxidant glutathione. 

Furthermore, it plays a role in the active transport of calcium and potassium ions across cell membranes, which is crucial for nerve impulse conduction, muscle contraction, and maintaining a normal heart rhythm.

An adult body contains approximately 25 grams of it, with 50% to 60% present in the bones and most of the rest in soft tissues. 

Less than 1% of the body's total amount of this mineral is in the blood serum, and these levels are tightly controlled.

Normal concentrations in the serum range between 0.75 and 0.95 millimoles (mmol)/L. A level below 0.75 mmol/L is defined as hypomagnesemia.

The kidneys largely control homeostasis of this mineral, typically excreting about 120 mg into the urine each day, with reduced excretion when the body's status is low.

Assessing this mineral's status is challenging because most of it resides inside cells or in bone.

The most commonly used and readily available method for assessment is the measurement of serum concentration, even though serum levels have little correlation with total body amounts or concentrations in specific tissues.

Other methods include measuring concentrations in erythrocytes, saliva, and urine; measuring ionized concentrations in blood, plasma, or serum; and conducting a loading (or tolerance) test.

No single method is considered satisfactory.

Some experts consider the tolerance test (in which urinary levels are measured after parenteral infusion of a dose) to be the best method to assess status in adults.

To comprehensively evaluate status, both laboratory tests and a clinical assessment might be required.

Recommended Intakes

Intake recommendations for magnesium and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies.

DRI is the general term for a set of reference values used to plan and assess nutrient intakes of healthy people.

These values, which vary by age and sex, include the following:

  • Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
  • Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
  • Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
  • Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.

Table 1 lists the current RDAs for magnesium. For infants from birth to 12 months, the FNB established an AI for this nutrient that is equivalent to the mean intake of magnesium in healthy, breastfed infants, with added solid foods for ages 7–12 months.

Table 1: Recommended Dietary Allowances (RDAs) for Magnesium [1]

Age
Male
           Female
       Pregnancy      
   Lactation
Birth to 6 months      
30 mg*
           30 mg*
7–12 months
75 mg*
           75 mg*
1–3 years
80 mg
           80 mg

4–8 years
130 mg
           130 mg

9–13 years
240 mg 
           240 mg

14–18 years
410 mg
           360 mg  
      400 mg
   360 mg
19–30 years
400 mg
           310 mg
      350 mg
   310 mg
31–50 years
420 mg
           320 mg
      360 mg
   320 mg
51+ years
420 mg
           320 mg


This nutrient plays a role in over 300 enzyme reactions in the human body, including aiding muscle and nerve function, regulating blood pressure, and supporting the immune system.

An adult body contains around 25 grams of magnesium, with 50-60% stored in the skeletal system. The rest is present in muscle, soft tissues, and bodily fluids.

Many people in the United States do not get enough of it in their diet, though deficiency symptoms are uncommon in otherwise healthy people.

Doctors link deficiency with a range of health complications, so people should aim to meet their daily recommended levels of magnesium.

Almonds, spinach, and cashew nuts are some of the foods highest in this nutrient.

If a person cannot get enough through their diet, their doctor may recommend taking supplements.

In this article, we explore the function and benefits of this nutrient, its role in the body, dietary sources, and possible health risks associated with too much of it.

Benefits of Magnesium

Magnesium is one of seven essential macrominerals.

These macrominerals are minerals that people need to consume in relatively large amounts — at least 100 milligrams per day.

Microminerals, such as iron and zinc, are just as important, though people need them in smaller amounts. 

This nutrient is vital for many bodily functions, and getting enough of this mineral can help prevent or treat chronic diseases, including Alzheimer’s disease, type 2 diabetes, cardiovascular disease, and migraines.

Bone Health

While most research has focused on the role of calcium in bone health, magnesium is also essential for healthy bone formation. 

Research has linked adequate magnesium intake with higher bone density, improved bone crystal formation, and a lower risk of osteoporosis in females after menopause. 

Magnesium may improve bone health both directly and indirectly, as it helps regulate calcium and vitamin D levels, which are two other nutrients vital for bone health.

Diabetes

Research has linked high magnesium diets with a lower risk of type 2 diabetes.

This may be because magnesium plays an important role in glucose control and insulin metabolism.

A 2015 review reports that most, but not all, people with diabetes have low magnesium and that it may play a role in diabetes management. [2]

A deficiency may worsen insulin resistance, which is a condition that often develops before type 2 diabetes.

On the other hand, insulin resistance may cause low levels. In many studies, researchers have linked high magnesium diets with diabetes.

Additionally, a systematic review from 2017 suggests that taking supplements can improve insulin sensitivity in people with low magnesium levels. [3]

However, researchers need to gather more evidence before doctors can routinely use magnesium for glycemic control in people with diabetes.

Cardiovascular Health

The body needs magnesium to maintain the health of muscles, including the heart. Research has found that magnesium plays an important role in heart health.

A 2018 review reports that magnesium deficiency can increase a person’s risk of cardiovascular problems. [4]

This is partly due to its roles on a cellular level. The authors observe that magnesium deficiency is common in people with congestive heart failure and can worsen their clinical outcomes.

People who receive magnesium soon after a heart attack have a lower risk of mortality.

Doctors sometimes use this nutrient during treatment for congestive heart failure (CHF) to reduce the risk of arrhythmia, or abnormal heart rhythm.

According to a 2019 meta-analysis, increasing intake may lower a person’s risk of stroke.

They report that for each 100 mg per day increase in magnesium, the risk of stroke reduced by 2%.

Some research also suggests that magnesium plays a role in hypertension.

However, the Office of Dietary Supplements (ODS) notes that based on current research, taking magnesium supplements lowers blood pressure to only a small extent.

The ODS calls for a “large, well-designed” investigation to understand the role of it in heart health and the prevention of cardiovascular disease.

Migraine Headaches

Magnesium therapy may help prevent or relieve headaches.

This is because a deficiency can affect neurotransmitters and restrict blood vessel constriction, which are factors linked to migraines.

People who experience migraines may have lower levels of magnesium in their blood and body tissues compared with others.

Magnesium levels in a person’s brain may be low during a migraine. A systematic review from 2017 states that this nutrient´s therapy may be useful for preventing migraines. [5]

The authors suggest that taking 600 mg of magnesium citrate appears to be a safe and effective prevention strategy.

The American Migraine Foundation reports that people frequently use doses of 400–500 mg per day for migraine prevention.

The amounts that may have an effect are likely to be high, and people should only use this therapy under the guidance of their doctor.

Premenstrual Syndrome (PMS)

Magnesium may also play a role in premenstrual syndrome (PMS).

Small-scale studies suggest that taking magnesium supplements along with vitamin B-6 can improve PMS symptoms.

However, a more recent 2019 review reports that the research is mixed, and further studies are needed. [6]

The American College of Obstetricians and Gynecologists suggest that taking supplements could help to reduce bloating, mood symptoms, and breast tenderness in PMS.

Anxiety

Magnesium levels may play a role in mood disorders, including depression and anxiety.

According to a 2017 systematic review, low magnesium levels may have links with higher levels of anxiety. [7]

This is partly due to activity in the hypothalamic-pituitary-adrenal (HPA) axis, which is a set of three glands that control a person’s reaction to stress.

However, the review points out that the quality of evidence is poor, and that researchers need to do high quality studies to find out how well supplements might work for reducing anxiety.

Dietary Sources

Magnesium is present in many foods, including:

  • Whole grains and dark-green, leafy vegetables
  • Nuts and seeds
  • Peas and beans
  • Fish
  • Whole grains and wheat germ
  • Bananas, apricots, and avocados
  • Hard water (tap water)

Magnesium Deficiency

Deficiency is uncommon in otherwise healthy people.

When it occurs, it can be due to inadequate magnesium intake, excess loss of magnesium from the body, or health conditions that reduce magnesium absorption.

People at risk of magnesium deficiency include those with gastrointestinal diseases, type 2 diabetes, alcohol dependence, and older adults.

Symptoms of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness.

Advanced deficiency can cause numbness, tingling, muscle cramps, seizures, personality changes, abnormal heart rhythms, and coronary spasms.

Risks and Side Effects

Although magnesium is generally safe when consumed in dietary amounts, excessive intake from supplements can lead to adverse effects.

High doses of magnesium from supplements or medications can cause diarrhea, nausea, and abdominal cramping.

Extremely high doses can lead to toxicity, resulting in hypotension, respiratory paralysis, and cardiac arrest.

Conclusion

This nutrient is a crucial mineral that supports various bodily functions, from bone health and cardiovascular function to blood glucose control and nerve function. 

Ensuring an adequate intake of this nutrient through a balanced diet can help prevent deficiency and support overall health. 

For those unable to meet their magnesium needs through diet alone, supplements may be beneficial under the guidance of a healthcare provider.

References

Office of Dietary Supplements - magnesium. (n.d.). https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ [1]

LD, M. W. R. (2023, October 25). Why do we need magnesium? https://www.medicalnewstoday.com/articles/286839#recommended-daily-intake

Barbagallo, M. (2015). Magnesium and type 2 diabetes. World Journal of Diabetes, 6(10), 1152. https://doi.org/10.4239/wjd.v6.i10.1152 [2]

Morais, J. B. S., Severo, J. S., De Alencar, G. R. R., De Oliveira, A. R. S., Cruz, K. J. C., Marreiro, D. D. N., De Jesus E Silva De Almendra Freitas, B., De Carvalho, C. M. R., De Carvalho E Martins, M. D. C., & De Macedo Gonçalves Frota, K. (2017). Effect of magnesium supplementation on insulin resistance in humans: A systematic review. Nutrition, 38, 54–60. https://doi.org/10.1016/j.nut.2017.01.009 [3]

DiNicolantonio, J. J., Liu, J., & O’Keefe, J. H. (2018). Magnesium for the prevention and treatment of cardiovascular disease. Open Heart, 5(2), e000775. https://doi.org/10.1136/openhrt-2018-000775 [4]

Von Luckner, A., & Riederer, F. (2017). Magnesium in migraine Prophylaxis—Is there an Evidence‐Based Rationale? A systematic review. Headache, 58(2), 199–209. https://doi.org/10.1111/head.13217 [5]

Moslehi, M., Arab, A., Shadnoush, M., & Hajianfar, H. (2019). The Association Between Serum Magnesium and Premenstrual Syndrome: a Systematic Review and Meta-Analysis of Observational Studies. Biological Trace Element Research, 192(2), 145–152. https://doi.org/10.1007/s12011-019-01672-z [6]

Boyle, N. B., Lawton, C., & Dye, L. (2017b). The Effects of Magnesium Supplementation On Subjective Anxiety and Stress—A Systematic Review. Nutrients, 9(5), 429. https://doi.org/10.3390/nu9050429 [7]

Moslehi, M., Arab, A., Shadnoush, M., & Hajianfar, H. (2019). The Association Between Serum Magnesium and Premenstrual Syndrome: a Systematic Review and Meta-Analysis of Observational Studies. Biological Trace Element Research, 192(2), 145–152. https://doi.org/10.1007/s12011-019-01672-z 

Healthdirect Australia. (2023, November 15). Magnesium and your health. Health Benefits and How Much You Need | Healthdirect. https://www.healthdirect.gov.au/magnesium

Healthdirect Australia. (n.d.). Magnesium deficiency. Symptoms, Causes, Treatment & Prevention | Healthdirect. https://www.healthdirect.gov.au/magnesium-deficiency

Goldman, R. (2024, May 22). 10 foods high in magnesium. https://www.medicalnewstoday.com/articles/318595

Schaefer, A. (2024, May 1). Can you have too much magnesium? Healthline. https://www.healthline.com/health/food-nutrition/magnesium-overdose-whats-the-likelihood