Magnesium Nutrition: A Mineral Underestimated But What Is It?


Magnesium, an abundant mineral in the body, is 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).

Magnesium 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.

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.

Magnesium also plays a role in the active transport of calcium and potassium ions across cell membranes. 

A process that is important to nerve impulse conduction, muscle contraction, and normal heart rhythm.

Adult body contains

An adult body contains approximately 25 g magnesium. 

With 50% to 60% present in the bones and most of the rest in soft tissues.

Less than 1% of total magnesium is in blood serum, and these levels are kept under tight control.

Normal serum magnesium concentrations range between 0.75 and 0.95 millimoles (mmol)/L.

Hypomagnesemia is defined as a serum magnesium level less than 0.75 mmol/L. Magnesium homeostasis is largely controlled by the kidney. 

Which typically excretes about 120 mg magnesium into the urine each day.

Urinary excretion is reduced when magnesium status is low.

Assessing magnesium status is difficult because most magnesium is inside cells or in bone.

The most commonly used and readily available method for assessing magnesium status is measurement of serum magnesium concentration. 

Even though serum levels have little correlation with total body magnesium levels or concentrations in specific tissues.

Other methods

Other methods for assessing magnesium status include measuring magnesium concentrations in erythrocytes, saliva, and urine. 

Measuring ionized magnesium concentrations in blood, plasma, or serum; and conducting a magnesium-loading (or “tolerance”) test.

No single method is considered satisfactory.

Some experts but not others consider the tolerance test (in which urinary magnesium is measured after parenteral infusion of a dose of magnesium) to be the best method to assess magnesium status in adults.

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

Our legs are probably one of the most active and abused parts of our body.

Legs are particularly important for motion and standing. Playing sports, running, and even for breaking a fall.

But these legs are also prone to pain as they, in combination with the hips, knees, ankles and feet, move the entire body’s weight and provide support.

In many cases, it is nearly impossible to determine the cause of leg cramps and leg pain.

Leg pain is a common symptom and complaint and finding a good leg pain relief can be taxing. Leg pain may include knee, foot, and other leg discomforts.

Pain in these areas can stem from injuries or conditions such as fractures, tendinitis (e.g., Achilles tendinitis, tennis elbow), shin splints, and carpal tunnel syndrome.

It may also include muscle cramps, injuries, inflammation, nerve damage, dehydration or depletion of potassium, sodium, calcium or the other mineral that is regarded as the “forgotten” mineral.

Magnesium is sometimes regarded as a “moothie” mineral since it has the ability to relax our muscles.

Our nerves also depend upon magnesium to avoid becoming over-excited.

The use of magnesium as a muscle relaxer is familiar to many individuals who have taken liquid magnesium.

Magnesium is usually referred to as a “macromineral,” which means that our food must provide us with hundreds of milligrams of magnesium every day.

Inside our bodies, magnesium is found mostly in our bones (60-65%), but also in our muscles (25%), and in other cell types and body fluids.

Like all minerals, magnesium cannot be made in our body and must therefore be plentiful in our diet in order for us to remain healthy.

Having an adequate magnesium in our diet can provide leg pain relief.

Magnesium is a mineral that is essential to many biological processes that occur in the body.

It aids in the body’s absorption of calcium and also plays a key role in the strength and formation of bones and teeth.

People at risk for osteoporosis can benefit from taking magnesium. Magnesium is also vital for maintaining a healthy heart.

It can help stabilize the rhythm of the heart and helps prevent abnormal blood clotting in the heart. It aids in maintaining healthy blood pressure levels.

This can significantly lower the chance of heart attacks and strokes, and can even aid in the recovery.

Magnesium also helps maintain proper muscle function.

It works to keep muscles properly relaxed.

Because of its benefits in relieving stiff muscles, magnesium can be especially beneficial to fibromyalgia patients.

Most people do not maintain proper levels of magnesium. But it would greatly benefit a lot of people if they supplement their diet with magnesium.

Health experts frequently emphasize the importance of having adequate levels of vitamins and minerals in the diet.

While most people try to stay informed about which vitamins and minerals are most beneficial to their health, there are still many nutrients that have benefits that are underestimated and even forgotten.

Magnesium is certainly one of these elements.

Essential for hundreds of chemical reactions that occur in the body every second, the mineral magnesium has received surprisingly little attention over the years.

Recent findings, however, suggest that it has important health-promoting benefits.

Sources of Magnesium


Magnesium is widely distributed in plant and animal foods and in beverages. Green leafy vegetables, such as spinach, legumes, nuts, seeds, and whole grains, are good sources.

In general, foods containing dietary fiber provide magnesium. Magnesium is also added to some breakfast cereals and other fortified foods.

Some types of food processing, such as refining grains in ways that remove the nutrient-rich germ and bran, lower magnesium content substantially.

Selected food sources of magnesium are listed in Table 2.

Tap, mineral, and bottled waters can also be sources of magnesium. 

But the amount of magnesium in water varies by source and brand (ranging from 1 mg/L to more than 120 mg/L).

Approximately 30% to 40% of the dietary magnesium consumed is typically absorbed by the body.

Table 2: Selected Food Sources of Magnesium 

(mg) per
Almonds, dry roasted, 1 ounce8020
Spinach, boiled, ½ cup7820
Cashews, dry roasted, 1 ounce7419
Peanuts, oil roasted, ¼ cup6316
Cereal, shredded wheat, 2 large biscuits6115
Soymilk, plain or vanilla, 1 cup6115
Black beans, cooked, ½ cup6015
Edamame, shelled, cooked, ½ cup5013
Peanut butter, smooth, 2 tablespoons4912
Bread, whole wheat, 2 slices4612
Avocado, cubed, 1 cup4411
Potato, baked with skin, 3.5 ounces4311
Rice, brown, cooked, ½ cup4211
Yogurt, plain, low fat, 8 ounces4211
Breakfast cereals, fortified with 10% of the DV for magnesium4010
Oatmeal, instant, 1 packet369
Kidney beans, canned, ½ cup359
Banana, 1 medium328
Salmon, Atlantic, farmed, cooked, 3 ounces267
Milk, 1 cup24–276–7
Halibut, cooked, 3 ounces246
Raisins, ½ cup236
Chicken breast, roasted, 3 ounces226
Beef, ground, 90% lean, pan broiled, 3 ounces205
Broccoli, chopped and cooked, ½ cup123
Rice, white, cooked, ½ cup103
Apple, 1 medium92
Carrot, raw, 1 medium72

*DV = Daily Value.

DVs were developed by the U.S. Food and Drug Administration (FDA) to help consumers compare the nutrient contents of products within the context of a total diet.

The DV for magnesium is 400 mg for adults and children aged 4 and older. However, the FDA does not require food labels to list magnesium content unless a food has been fortified with this nutrient.

Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

The U.S. Department of Agriculture’s (USDA’s) Nutrient Database Web site lists the nutrient content of many foods and provides comprehensive list of foods containing magnesium arranged by nutrient content and by food name.