Magnesium

Background Info:

  • Abundant mineral in the body
  • Naturally present in many foods, added to food products, available as a dietary supplement, and present in some medicines (antacids, laxatives)
  • Cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body

Health Benefits: 

  • Healthy blood pressure
  • Muscle and nerve function
  • Helps with bone growth
  • Maintaining blood glucose levels
  • Plays a major role in the development of serotonin
  • Protein synthesis
  • Required for the synthesis of DNA, RNA, and the antioxidant glutathione
  • Required for energy production, oxidative phosphorylation, and glycolysis
  • 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

Recommended Dietary Allowance:

  • Male & Female
    • 0-6 months: 30 mg
    • 7-12 months: 75 mg
    • 1-3 years: 80 mg
    • 4-8 years: 130 mg
    • 9-13 years: 240 mg
  • Male
    • 14-18 years: 410 mg
    • 19-30 years: 400 mg
    • 31-50+ years: 420 mg
  • Female
    • 14-18 years: 360 mg
    • 19-30 years: 310 mg
    • 31-50+ years: 320 mg
    • add 40 mg if pregnant

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.

  • Almonds – 80 mg in 1 oz
  • Apple – 9 mg in 1 medium
  • Avocado – 44 mg in 1 cup
  • Banana – 32 mg in 1 medium
  • Black beans – 60 mg in 1/2 cup
  • Brown rice – 42 mg in 1/2 cup
  • Carrot – 7 mg in 1 medium
  • Cashews – 74 mg in 1 oz
  • Chicken breast – 22 mg in 3 oz
  • Edamame – 50 mg in 1/2 cup
  • Halibut – 24 mg in 3 oz
  • Kidney beans – 35 mg in 1/2 cup
  • Peanut butter – 49 mg in 2 tablespoons
  • Peanuts – 63 mg in 1/4 cup
  • Potatoes with the skin – 43 mg in 3.5 oz
  • Raisins – 23 mg in 1/2 cup
  • Salmon – 26 mg in 3 oz
  • Spinach – 78 mg in 1/2 cup
  • Soy milk – 61 mg in 1 cup
  • Yogurt – 42 mg in 8 oz

Cooking: 

  • Can lower the levels found in foods

Storage, Absorption, and Excretion: 

  • An adult body contains approximately 25 g magnesium
    • 50% to 60% present in the bones
    • 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
  • 30-40% of dietary magnesium is absorbed
  • 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 Status: 

  • 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 for assessing magnesium status include:
    • Measuring magnesium concentrations in erythrocytes, saliva, and urine
    • Measuring ionized magnesium concentrations in blood, plasma, or serum
    • Conducting a magnesium-loading (or “tolerance”) test.
  • No single method is considered satisfactory
  • To comprehensively evaluate magnesium status, both laboratory tests and a clinical assessment might be required

Deficiency:

  • Irritability, fatigue, mental confusion, predisposition to stress

Daily Upper Limit:

  •  Taking more than 350 mg from supplements can cause diarrhea and stomach creamping

 References:

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2 thoughts on “Magnesium

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