Magnesium: Your Essential Guide

Magnesium is one of the most asked about supplements in my practice.  It’s no surprise given it does so many things in our body including supporting nerve function, muscle function, maintaining a healthy heart rhythm and blood pressure, supporting bone health and blood sugar metabolism.  Not to mention helping with sleep, migraines and bowel movements. This blog post will cover all the basics of magnesium including how to get more from food, what causes deficiencies, how blood levels are assessed, potential cautions, and answers to your most pressing questions about supplementation.

Magnesium-Rich Foods

Nature provides us with an abundance of magnesium-rich foods. While many foods contain

this essential mineral, some are particularly concentrated sources, making it easier to meet your daily needs. Magnesium-rich foods include:

• pumpkin seeds

• chia seeds

• almonds

• spinach 

• cashews

• Black beans

• Soy beans/edamame 

• peanuts

• potatoes 

• brown rice

• yogurt

The Magnesium Gap: What Causes Deficiency?

Many people are not getting enough magnesium in their diet.  There can be many reasons for this including personal preferences and digestive issues.  Additional factors that can contribute to inadequate magnesium in the body include: 

• Type 2 Diabetes and Insulin Resistance: These conditions can lead to increased urinary excretion of magnesium, resulting in greater losses from the body.

• Alcohol Use: Regular alcohol consumption can impair magnesium absorption and increase its excretion.

• Aging: As we age, the efficiency of nutrient absorption, including magnesium, tends to decrease.

• Medications: Certain medications are known to deplete magnesium levels. These include diuretics and proton pump inhibitors (PPIs).

Beyond the Blood Test: Understanding Magnesium Levels

How do you know if you are low in magnesium?  It’s not as simple as taking a blood test.  Because of how important magnesium is for our heart rhythm, our bodies work hard to keep enough magnesium in the blood.  Where does it get it from if we are not eating enough?  Our bones and muscles.  Usually when blood levels of magnesium are low or high it is related to a long-term medication, malabsorption, chronic diarrhea or kidney disease.  How many dietitians including myself assess the need for magnesium is based on a person’s intake, health conditions, medications and symptoms. In other words, you don’t have to have low blood levels of magnesium to benefit from increasing intake from food or taking a supplement.

Your Questions Answered: Navigating Magnesium Supplements

What is the best form of magnesium to take?

The "best" form of magnesium largely depends on your individual needs. 

• Magnesium Oxide/Hydroxide: Often found in laxatives, these forms have lower bioavailability.  They are not ideal for treating magnesium deficiency and should only be used as recommended.  Excess laxative use can be dangerous and is discussed later in this article.

• Magnesium Citrate: This is a popular and well-absorbed form, often used to relieve constipation due to its mild laxative effect. It's also effective for increasing magnesium levels and supporting relaxation and sleep.  It is sometimes used as a source of citrate to reduce risk of kidney stones.

• Magnesium Glycinate: Highly bioavailable and generally well-tolerated, this form is less likely to cause digestive upset. It's often recommended for sleep.

• Magnesium Threonate: This form is unique for its ability to cross the blood-brain barrier and may help with mood, brain health and sleep.

• Magnesium Malate: It's well-absorbed which means it is less likely to cause digestive upset.

• Magnesium Taurate: The taurine in this form may provide added support for managing blood pressure, supporting blood sugar metabolism and reducing insulin resistance.

• Magnesium Orotate: There is limited information to support taking this over other forms and to justify the higher cost.  Research looking at orotate forms and heart health compared this supplement to placebo, not other forms of magnesium so we don't know if the improvements were related to increased magnesium intake in general or the orotate compound.

Does the time of day make a difference?

Generally, magnesium supplements can be taken at any time of day, and consistency is often more important than the exact timing.  However, when you are looking for magnesium to help with symptoms timing may make a difference.

• Morning: If you're taking magnesium to help with mood or migraines, taking it in the morning may be worth trying.

• Evening: For those using magnesium to improve sleep quality, taking it in the evening before bed is most helpful.  This is also a good time to take magnesium to help with bowel movements as it can help promote a morning bowel movement and help with sleep.

Important Cautions and Considerations

Quality Supplements: While magnesium is essential, there are important cautions to consider when using supplemental forms.  It's always advisable to choose reputable brands that have third party testing to minimize the likelihood of contamination and ensure accurate dosing. Popular doesn't meant it is safe.

Urine pH: Magnesium citrate can increase urine pH.  In some cases this is beneficial but may not be for people that form calcium phosphate kidney stones and tend toward high urine pH to begin with.

Toxicity: Symptoms of excess magnesium can include diarrhea, nausea, abdominal cramping, low blood pressure, muscle weakness, and in severe cases, irregular heartbeat or heart attack. This is more likely to happen for those with stage 4 or 5 kidney disease as the kidneys have a harder time regulating magnesium levels in the blood. Even still toxicity is rare.

Medication and supplement interactions: 

• Taking magnesium at the same time as iron supplements may reduce iron absorption. 

• Magnesium interferes with the absorption of certain medications, including gabapentin, bisphosphonates, and some antibiotics. 

Caution when using as a laxative:

• Excess use of laxatives can lead to dehydration, electrolyte imbalances and organ damage.  Please talk with your doctor if you have been taking laxatives for more than a week.

Interested in Learning More?

If you would like to learn more about magnesium and if you might need more of it, how much and which forms are safe to take or if it is best to meet your needs from food, click here to schedule a visit with Nikki.

This blog is for educational and informational purposes only and solely as a self-help tool for your own use. I am not providing medical, psychological, or nutrition therapy advice. You should not use this information to diagnose or treat any health problems or illnesses without consulting your own medical practitioner. Always seek the advice of your own medical practitioner and/or mental health provider about your specific health situation.