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Magnesium
Recommended Intake
Magnesium Deficiency
Magnesium Toxicity
Major Food Sources
Health Considerations
Tips for Increasing Your Magnesium Intake

Magnesium is an essential mineral that has a hand in many vital body functions: releasing energy, regulating body temperature, building protein, and stabilizing bone. It is also one of several nutrients that helps keep blood pressure within a healthful range. And since magnesium is plentiful in vegetables, legumes, and whole grains, it is easy to consume enough if you are eating a healthful diet.

Magnesium's functions include:

  • activating more than 300 enzymes (chemicals that regulate a variety of body functions, including making body proteins and causing muscle contractions)
  • aiding in the metabolism of fat and carbohydrate to produce energy
  • binding with ATP to form "active ATP," which provides energy for almost all metabolic reactions and processes
  • ensuring proper nerve and muscle function, and keeping heart rhythm steady
  • helping synthesize nucleic acids (DNA and RNA) and proteins, which are the building blocks of body tissue
  • giving structure to cell membranes
  • helping keep bones healthy
  • decreasing the risk of tooth decay by binding calcium to tooth enamel

 

Recommended Intake

Age Group

Recommended Dietary Allowance (mg/d)

Male

Female

0-6 months

Adequate intake (AI) = 30

AI = 30

7-12 months

AI = 75

AI = 75

1-3 years

80

80

4-8 years

130

130

9-13 years

240

240

14-18 years

410

360

19-30 years

400

310

31-50 years

420

320

50-70 years

420

320

>70 years

420

320

Pregnancy

   

<18 years

n/a

400

19-30 years

n/a

350

31-50 years

n/a

360

Lactation

   

<18 years

n/a

360

19-30 years

n/a

310

31-50 years

n/a

320

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Magnesium Deficiency
Magnesium deficiency is rare, because most people have large stores of this mineral in their body. However, it can be caused by diseases or medications that interfere with the body's ability to absorb magnesium. Symptoms of a magnesium deficiency include: irregular heartbeat, nausea, confusion, depression, tingling, weakness, loss of appetite, and muscle contractions and cramps.

Conditions and medications that may lead to a magnesium deficiency include:

  • gastrointestinal disorders, such as:

    severe diarrhea
    chronic or severe vomiting
    surgical removal of part of the intestine
    intestinal inflammation

  • malabsorptive disorders; these include:

    Crohn's disease
    cystic fibrosis
    celiac disease
    steatorrhea
    diseases of the pancreas, liver, or gallbladder

  • thiazide diuretics, such as Lasix, Bumex, Edecrin, and Hydrochlorothiazide, which can increase loss of magnesium in the urine
  • Cisplatin, a drug used to treat cancer
  • certain antibiotics, including Gentamicin, Amphotericin, and Cyclosporin
  • poorly controlled diabetes, which can increase the loss of magnesium through urine
  • alcoholism (Alcohol increases urinary excretion of magnesium; also, alcoholics typically have poor diets that are lacking in many essential nutrients, including magnesium.)
  • kidney disease

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Magnesium Toxicity
Magnesium toxicity is not a concern for most healthy people. However, people with kidney disease may develop toxicity. This is because the kidneys are responsible for regulating the level of magnesium in the blood. Symptoms of magnesium toxicity include:

  • weakness
  • nausea
  • malaise (general discomfort or an "out-of-sorts" feeling)

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Major Food Sources
Magnesium is found in a variety of foods. The best sources are legumes, nuts, whole grains, and certain vegetables. "Hard" water (which is high in dissolved minerals, specifically calcium and magnesium) is also a source of magnesium.

Food

Serving size

Magnesium content (mg)

Artichoke, boiled

1 medium

180

Pumpkin & squash seeds, roasted

1 ounce

151

Tofu, raw, firm

1/2 cup

118

Navy beans, boiled

1 cup

107

Almonds, dry roasted, unsalted

1 ounce

91

Black-eyed peas, boiled

1 cup

86

Lima beans, boiled

1 cup

81

Chickpeas (garbanzo beans), boiled

1 cup

79

Spinach, boiled

1/2 cup

78

Swiss chard, boiled

1/2 cup

76

Cashews, dry roasted

1 ounce

74

Avocado, raw, California

1 medium

71

Lentils, boiled

1 cup

71

Sweet potato, canned, mashed

1 cup

61

Potato, microwaved with skin

1 medium

55

Peanut butter

2 tablespoons

51

Acorn squash, baked

1/2 cup cubes

44

Whole wheat spaghetti, cooked

1 cup

42

Wheat germ, toasted

2 tablespoons

41

Sunflower seeds, dry roasted

1 ounce

37

1% milk

1 cup (8 fluid oz.)

34

Whole wheat bread

1 slice

24

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Health Considerations

  • Blood Pressure
    A greater magnesium intake is associated with a lower incidence of high blood pressure. This is the finding of a few large clinical studies. One of these, the DASH study (dietary approaches to stop hypertension), found that a diet high in magnesium, potassium, and calcium, and low in sodium and fat can significantly lower blood pressure. You can get these nutrients by eating a diet rich in fresh fruits and vegetables, legumes, whole grains, and low-fat dairy foods. Another group of researchers studied 30,000 U.S. male health professionals over several years. Their finding-a greater magnesium intake was significantly associated with a lower risk of hypertension.

    Based on the growing number of studies showing a positive role for magnesium in managing blood pressure, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends maintaining an adequate magnesium intake to prevent and manage high blood pressure.

  • Heart Disease
    Several studies have found links between magnesium status and heart health. Many of these studies suggest that an adequate intake of magnesium is protective of the heart. However, the findings are still not clear, and further study needs to be done to clarify magnesium's role.

  • Osteoporosis
    Since a significant amount of magnesium is stored in the bones, and one of magnesium's roles is to help keep bones healthy, it would make sense that magnesium would help protect bones from the thinning of osteoporosis. Several studies have suggested just that — magnesium supplementation may improve bone mineral density.

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Tips for Increasing Your Magnesium Intake
It is easy to meet your magnesium needs through foods. To increase your intake, try some of the following:

  • Sprinkle wheat germ over your morning bowl of cereal or oatmeal, and on top of casseroles or in baked goods.
  • Throw a handful of nuts into a spinach salad to add a little crunch and some extra nutrition.
  • Wrap beans, rice, sauteed vegetables, and a little bit of cheese in a warm tortilla for lunch.
  • Add beans to dishes like chili, soup, salad, pasta, or rice.
  • Have a bowl of whole grain cereal for breakfast or to snack on; if you're not used to the taste, mix it with your usual cereal.
  • Bake a potato and top it with sauteed spinach, black beans, and salsa.
  • Spread peanut butter on your toast or bagel instead of butter, margarine, or cream cheese.

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