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Food and Nutrition

Food for Thought: Magnesium Supplements

Dana Calidonna, RD | Nutrition Specialist
/ May 11, 2023
Foods high in magnesium - leafy greens, legumes, avocado

Magnesium is a popular supplement right now for sleep and constipation. But is it something that you need to be taking? This week’s food thought aims to explore your questions about this spotlight supplement.

What Is Magnesium?

What is magnesium anyway? Magnesium is a mineral that participates in around 300 enzyme systems within our body, including protein synthesis, muscle and nerve function (like regulating our heart rhythm), blood glucose control, blood pressure regulation, and the structural development of bone — pretty important stuff! You can find magnesium in a wide variety of foods. These include green leafy vegetables like spinach, legumes, nuts, seeds, and whole grains. In general, foods containing dietary fiber provide magnesium, with nuts and seeds being especially prolific sources.

Assessing magnesium status is difficult because our bodies store most of their magnesium within the bones or inside cells. But dietary surveys consistently show low levels of magnesium intake, and due to soil depletion even the high magnesium foods that we do eat may not be providing enough. So supplementing can be helpful especially to help treat conditions such as insomnia and constipation. Magnesium supplements come in many different forms (magnesium glycinate, magnesium citrate, and magnesium oxide being the most common) and differ based on their absorbability and specific uses. So it’s important to know which form you are taking and for what reason.

Magnesium Supplements for Sleep

Research shows that magnesium plays an important role in stimulating relaxation pathways, including the production of gamma-aminobutyric acid (GABA), a neurotransmitter responsible for quieting your nervous system and promoting sleep. Magnesium glycinate is magnesium bound to the non-essential amino acid glycine. Glycine, along with many other neurotransmitters (chemicals in the brain) promote feelings of calm and a healthy circadian rhythm. This form of magnesium is quickly absorbed in our gastrointestinal tract and so will start working right away to help you relax and fall asleep faster. Because of its calming effects, this form of magnesium can also be used to help with anxiety and stress relief.

Magnesium Supplements for Constipation

Magnesium citrate or magnesium oxide are good options for those looking to treat constipation. Both supplements have an osmotic effect on our colon and work by pulling water into the intestines making bowel movements softer and easier to pass. You might be familiar with magnesium oxide in medications such as Milk of Magnesia. Magnesium bound to oxygen ions (oxide) is less bioavailable than magnesium citrate (magnesium bound to the inorganic salt citrate) and more poorly absorbed by our digestive tract. This poor absorption leads to a stronger laxative effect than magnesium citrate. If you are looking for a gentler way to get things moving, magnesium citrate is a better choice.

In summary, adding a magnesium supplement may be a helpful and more natural step in the treatment of insomnia and/or constipation. As with any supplements, best to discuss with your care team first before starting.


  1. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
  2. https://doi.org/10.1016/j.heliyon.2020.e05390
  3. https://www.healthline.com/nutrition/best-magnesium-supplement
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