Fast Facts: Magnesium

While present in only small amount in the body, magnesium is nonetheless one of the most important dietary micronutrients. In over 300 of the chemical reactions required to sustain life, it acts a co-factor – essentially a “helper molecule” that is needed for an enzyme to carry out its function. Many of these reactions have a key role in creating your body’s energy and in efficient nervous system function. On a whole-body level, many people report that magnesium has a calming effect, helping to manage anxiety, decreasing muscle cramps, and can lead to better sleep.

Men tend to need more than women, thanks to a generally larger body size, however most people have a much-lower-than-recommended intake daily basis. In Australia, a national health survey in 2011-2012 showed that anywhere from one-third to one-half of the population did not meet the required intake, depending on age group (older adults are at higher risk.) A 2005-2006 survey in the United States found that a majority of Americans did not meet estimated average requirements (EAR) of magnesium, and it should be noted that the EAR measure is the intake level estimated to meet the requirements of 50% of healthy individuals, which may be a lower level than your individual requirements. In short, most of us don’t get adequate magnesium supplies from food.

This can be due in part to food choices (some are more magnesium-rich than others) as well as the impact of other nutrients on the body’s ability to absorb magnesium. Additionally, some diseases and health conditions can impact the body’s ability to absorb the mineral, and some lifestyle choices – like higher levels of physical activity or exercise – can lead to higher intake requirements.

 

Magnesium is involved in:
  • Cellular energy production via carbohydrate and fat metabolism
  • Protein and DNA synthesis
  • Regulates transport of ions (chemical molecules) across cell walls, plays a large role the muscle cells ability to contract and relax
  • Chemical reactions that create cellular “second messengers” that send signals within a cell
  • Movement of cells to damaged areas, and wound healing
  • More than 300 enzyme-driven chemical reactions all over the body
Food sources of magnesium include:
  • Dark leafy greens, especially spinach and Swiss chard
  • Nuts and seeds, especially pumpkin and sunflower seeds
  • Beans and legumes
  • Whole grains, especially quinoa, buckwheat, brown rice, and barley
  • Potatoes
Getting too much magnesium can lead to:
  • Diarrhea
  • Fatigue, weakness, and sleepiness
  • Shortness of breath
  • Very low blood pressure
Not getting enough magnesium can lead to:
  • Abnormal heart rhythms
  • Muscle cramps or twitching
  • Nausea and loss of appetite
  • Problems with moods, thinking, and memory
More on magnesium:
  • The body has complex controls to help regulate magnesium levels. You may absorb more of the mineral from food if your intake is low, and excrete more if your intake is high. (Even with high absorption, you can still have inadequate intake.)
  • Role in bone integrity: Up to 60% of your magnesium is stored in your bones, and as such, it plays a key role in bone metabolism. Studies have shown a low levels of long-term magnesium deficiency can lead to a significant amount of bone loss.
  • Role in blood sugar control: Studies have found that low magnesium can worsen blood sugar control, and that improvements in control are seen when low magnesium levels increase.
  • May help decrease risk of Type 2 Diabetes: Diets high in magnesium are associated with a significantly lower risk of diabetes.
Magnesium combined with other medications and health conditions:

Taking vitamins or minerals may have adverse effects when combined with some over the counter or prescription medications, and some medications can decrease absorption. Some health conditions can be impacted by high magnesium intakes. Talk to your doctor prior to increasing your magnesium intake if you have or are taking:

  • Diabetes
  • Alcoholism
  • Nutrient interactions: Very high doses of fiber, protein, and zinc supplements may make it more difficult to absorb magnesium, and Vitamin D and calcium may help absorption. More research is needed to confirm this though, especially outside of laboratory conditions (i.e. in the real world).
  • Bisphosphonates: Medications or supplements that are high in magnesium can decrease oral bisphosphonates absorption, such as medications used to treat osteoporosis.
  • Antibiotics: Magnesium can prevent the absorption of some antibiotics.
  • Diuretics: Long-term use of some diuretics can increase the loss of magnesium in urine and lead to depletion. In contrast, other diuretics can reduce magnesium excretion.
  • Proton pump inhibitors (used to decrease stomach acid): When taken for prolonged periods (typically more than a year) these drugs can cause low magnesium levels.
Reference List
Lukaski, H.C. (2001). Magnesium, zinc, and chromium nutrition and athletic performance. Can. J. Appl. Physiol. 26(Suppl.): S13-S22.
Berardi, J., Andrews, R., St. Pierre, B., Scott-Dixon, K., Kollias, H., & DePutter, C. (2017). The Essentials of Sport and Exercise Nutrition, Third Edition. Toronto: Precision Nutrition, Inc.
ODell, B. L., & Sunde, R. A. (1997). Handbook of nutritionally essential mineral elements. New York: Marcel Dekker.
Office of Dietary Supplements. (2016, February 11). Office of Dietary Supplements – Magnesium. Retrieved October 16, 2017, from https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/

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