Magnesium 101

Written By Rachel Hilts

Co-Written by Megan Churchill, Dietetics Student

What is Magnesium and Why does it matter?

Magnesium is one of the major minerals we need from our diet (1,2). Most of the magnesium in our body is stored in our bones (60%), however, there is approximately 40% stored in our soft tissues, and less than 1% in our blood (2,3). Due to the low amount of magnesium in our blood, it can be difficult to test for a deficiency (2).

Magnesium is very important because it is involved in over 300 reactions in our body!

 

Magnesium is involved in (2,4):

  • Protein synthesis

  • Nerve function

  • Muscle contractions

  • Blood glucose control

  • Glycolysis (the breakdown of glucose)

  • Regulating blood pressure

  • Synthesis of both DNA and RNA

  • Bone development

  • Immune system function

  • Heart rhythm

Basically, any function of the body you can think of, magnesium plays a role, so it is important to have adequate amounts of magnesium in your diet.

Roughly 1 in 3 Canadians are not meeting the recommended intake of magnesium through food (8)!

Magnesium.png

Food sources of magnesium (1,3,4):

  • Nuts

  • Seeds

  • Legumes

  • Leafy green vegetables

  • Fish

Pumpkin seeds are one of my favourite sources of magnesium! One quarter cup of pumpkin seeds makes up roughly half of your daily magnesium needs.

 

If you think you are not consuming enough magnesium-rich foods, it may be a good idea to consider taking a magnesium supplement. There are many magnesium supplements available so it may be confusing to know which one is right for you. The three main magnesium supplements are magnesium citrate, magnesium oxide, and magnesium glycinate.

Magnesium supplements may also be helpful for you if you suffer from frequent migraines, severe PMS, or anxiety or sleep disorders, but it’s always important to discuss these concerns with your healthcare team prior to starting a supplement (9, 10, 11).

 

Types of Magnesium Supplements:

Magnesium citrate is commonly used as a laxative; treating constipation short-term (one week or less) (5). It is available in a powder form, and is mixed into a liquid to drink, and can take from 30 minutes to 6 hours to work (5). The most common side effect of magnesium citrate is loose, watery stools, due to its laxative effects (5). This supplement works by pulling water into the intestines to make your bowel movements softer and easier to pass. Unlike magnesium oxide, the laxative effect is much more tolerable. Magnesium citrate can also be a helpful form of magnesium for migraine prevention (9).

Pro’s of Magnesium Citrate:

  • Inexpensive and easily absorbed

  • Can help as a constipation aid, as it works as a gentle laxative

  • Commonly available

  • May help reduce migraines

Con’s of Magnesium Citrate:

  • Not a good choice if you already have loose bowel movements

 

Similarly to magnesium citrate, magnesium oxide has some laxative properties, so it may be effective for people experiencing constipation (6). It is important to note – if you are using magnesium oxide as a laxative, it should only be used short-term, taken with a glass of water or juice, and should NOT be taken on an empty stomach (6). Magnesium oxide tends to have a much more significant laxative effect than citrate. Additionally, when taking magnesium oxide, other medications should be taken 2 hours apart (6). When taking a magnesium oxide supplement, abdominal discomfort is a common side effect (6).

Pro’s of Magnesium Oxide:

  • Commonly available

  • Effective as a short term laxative

Con’s of Magnesium Oxide:

  • Poorly absorbed form of magnesium

  • Requires high doses in order to correct a magnesium deficiency

  • May cause diarrhea

  • Not recommended for long term use.

 

Magnesium glycinate is a commonly prescribed supplement for those not experiencing constipation. It is well absorbed by our body because the magnesium in the supplement is bound to glycine (glycine helps to absorb magnesium) (7). If you have a deficiency in magnesium, a magnesium glycinate supplement can help to improve bone health, maintain normal health rhythm, and MAY help reduce any pain in your body.

Pro’s of Magnesium Glycinate:

  • Very well absorbed

  • The least amount of digestive side effects

  • Because it is bound to the amino acid glycine, it may have an additional calming effect for stress or anxiety

  • Safest option for correcting a long term deficiency

Con’s of Magnesium Glycinate:

  • Less commonly available

  • May have a higher cost

 

If you are taking a magnesium supplement be sure to inform all of your health care providers, this way they can be sure that no medications or nutrients are interacting negatively together.

 

If you are unsure if you should be taking a magnesium supplement, want advice around which supplement to choose, or want to learn how to incorporate more magnesium-rich foods in your diet, contact me to book an appointment.

References:

1.     Gropper SS. Smith JL, Carr TP. Advanced Human Nutrition and Human Metabolism. 7th ed. Boston: Cengage; 2018.

2.     National Institutes of Health. Magnesium: Face Sheet for Health Professionals [Internet]. 2021 [Cited 13 June 2021]. Available from: https://ods.od.nih.gov/factsheets/Magnesi um-HealthProfessional/

3.     Jahnen-Dechent W, Ketteler M. Magnesium basics. Clin Kidney J. 2012; 5(Suppl_1): i3-i14.  

4.     MedlinePlus. Magnesium in diet [Internet]. U.S. National Library of Medicine. 2019 [Cited 14 June 2021]. Available from: https://medlineplus.gov/ency/article/002423.htm

5.     MedlinePlus. Magnesium citrate [Internet]. U.S. National Library of Medicine. 2019 [Cited 14 June 2021]. Available from: https://medlineplus.gov/druginfo/meds/ a619019.html

6.     MedlinePlus. Magnesium oxide [Internet]. U.S. National Library of Medicine. 2015 [Cited 14 June 2021]. Available from: https://medlineplus.gov/druginfo/meds/a601074.html

7.     Zielinski L. Types of magnesium supplements: the differences explained. HealthGuide. 2019 [Cited 14 June 2021]. Available from: https://www.getroman.com/health-guide/types-of-magnesium/

8. Health Canada. Do Canadian Adults Meet Their Nutrient Requirements Through Food Intake Alone? 2012. Available from: https://www.canada.ca/en/health-canada/services/food-nutrition/food-nutrition-surveillance/health-nutrition-surveys/canadian-community-health-survey-cchs/canadian-adults-meet-their-nutrient-requirements-through-food-intake-alone-health-canada-2012.html#b1

9. Yablon LA, Mauskop A. Magnesium in headache. In: Vink R, Nechifor M, editors. Magnesium in the Central Nervous System [Internet]. Adelaide (AU): University of Adelaide Press; 2011. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507271/

10. Facchinetti F, Borella P, Sances G, Fioroni L, Nappi RE, Genazzani AR. Oral magnesium successfully relieves premenstrual mood changes. Obstet Gynecol. 1991 Aug;78(2):177-81. PMID: 2067759.

11. Boyle NB, Lawton C, Dye L. The Effects of Magnesium Supplementation on Subjective Anxiety and Stress-A Systematic Review. Nutrients. 2017;9(5):429. Published 2017 Apr 26. doi:10.3390/nu9050429

Rachel Hilts
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