Magnesium: Why Do We Need It?

 Written by Leighann Dewitt MS, RD, LD/N

Have you ever felt anxious, irritable, achy, stiff or suffer from insomnia? Have you just accepted this as your “norm”? Well, you may be lacking a very important nutrient in your body, Magnesium also referred to as the relaxation mineral. 

Magnesium (Mg) is the fourth most abundant mineral in the body. It is essential and plays a critical role, involved in more than 300 metabolic reactions! These reactions are not only important for normal everyday function but also for optimal athletic performance. Magnesium helps maintain normal nerve and muscle function, heart rhythm, blood pressure, immune system function, protein synthesis, bone integrity, blood glucose levels and promotes calcium absorption (just to name a few). Mg is found in all your tissues but most Mg in the body is found in your bones, muscles, and brain. Mg deficiency is linked to inflammation and higher levels of CRP (a protein produced by the liver which increases in the body when there is a condition causing inflammation). The list of conditions related to magnesium deficiency is extensive, some of which include depression, ADHD, migraines, insomnia, type II diabetes, asthma, atherosclerosis coronary heart disease, and osteoporosis. Some signs of magnesium deficiency include muscle cramps or twitches, irritability, anxiety, constipation, headaches, high blood pressure, gastric reflux, chronic fatigue. 

So, why are up to HALF of Americans deficient in Mg? 

Well, there are a few good reasons but the most common is the consumption of the Standard American Diet (SAD, perfect acronym). Many of us consume too many, if not solely; foods that are highly processed and refined, containing virtually no magnesium. Other reasons may include soft water, calcium supplementation, OTC/prescription medications, diuretic use, excessive menstruation, excess alcohol/coffee intake, intense/prolonged stress, antibiotic use, digestive disorders such as Crohn’s or IBS (irritable bowel syndrome). Athletes are at even higher risk for Mg deficiencies as human studies have shown that as physical activity increases, the need for Mg increases as well. 

To further complicate things, Mg is often poorly absorbed and easily lost from our bodies. In order for Mg to be properly absorbed we need a lot in our diet and enough Vitamin B6, Vitamin D (which most of us are also deficient in), and selenium. 

Another reason that many of us are deficient and may not know is that the standard magnesium serum test is the least sensitive marker of magnesium status. This is due to a lag time between serum changes and subclinical deficiency. The best marker for magnesium status is the magnesium loading test but this is not practical and can be expensive. 

So, we know magnesium is essential but can it actually enhance exercise performance? 

Animal studies have even indicated that Mg supplementation might improve exercise performance via enhancing glucose availability in the brain, muscle, and blood; and reducing/delaying lactate accumulation in the muscle. Studies have shown that Mg distribution and utilization are regulated by exercise and that muscle performance is positively associated with adequate serum magnesium levels. 

How much Magnesium do I really need? 

The Recommended Dietary Allowance (RDA) for Mg is 400-420mg for adult males and 310-320mg for adult females. Some magnesium-rich foods include almonds (80mg per oz.), Cooked spinach (78mg per 1⁄2 oz.), peanut butter (49mg per 2 Tbsp), Beef/chicken (20-22mg per 3 oz.), avocado (44mg per 1 cup). 

Do I need to Supplement Mg? 

Consuming magnesium-rich, whole foods is the optimal strategy for ensuring adequate levels of magnesium, however, oral supplementation is an option. Magnesium in the forms of citrate, lactate, glycinate and chloride forms are better absorbed and more bioavailable than the oxide and sulfate forms. Other ways to supplement Mg include taking a hot bath with Epsom salts (magnesium sulfate). People with heart or kidney issues should consult an MD before oral supplementation of Mg. 

Dislike plain Avocados like me? Here is a great way to incorporate them! 

Avocado Pudding Recipe 

*makes 2-3 servings 

2 Medium Hass Avocados 

2/3 cup milk (heavy cream for more of a mousse or almond milk as a vegetarian option) 

2 Tbsp Cacao (not cocoa) 

1 Tbsp stevia (or desired sweetener) 

1 tsp salt 

Optional: vanilla extract, cinnamon for added flavor 

  1. Mix all ingredients in blender 2. Remove and place into covered bowl and chill in the refrigerator for one hour 3. Enjoy! 




Volpe, S. L. (2015). Magnesium and the Athlete. Nutrition and Ergogenic Aids, 14(4), 279-283. 

Zhang, Y., Xun, P., Wang, R., Mao, L., & He, K. (2017). Can Magnesium Enhance Exercise Performance? Nutrients. doi:10.3390/nu9090946 

Hyman, M. (2010, March 18). Magnesium: The Most Powerful Relaxation Mineral Available. Retrieved June 25, 2019, from powerf_b_425499


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