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The Three Most Common Reasons For Magnesium Deficiency

What are common factors that cause Magnesium deficiency?

  • Low intake of magnesium-rich foods, particularly green leafy vegetables, is a significant contributor to magnesium deficiency.

  • Poor intestinal absorption of minerals, especially due to alkaline conditions, and the presence of phytates in certain foods hinder magnesium absorption.

  • Excessive excretion of magnesium, influenced by factors like alcohol consumption and certain health conditions, further exacerbates deficiency.

In a world filled with an abundance of food choices, it's paradoxical that 45% of the US population are experiencing a deficiency in a crucial mineral for their health: Magnesium.

“Overfed and undernourished”

magnesium nuts

This deficiency is not only pervasive but also often overlooked, leading to a myriad of health issues. 

In the realm of nutritional health, magnesium often takes a backseat to more buzzworthy vitamins and minerals. Yet, its importance cannot be overstated, as it plays a crucial role in over 600 bodily functions [1]. Despite its significance, magnesium deficiency remains a prevalent issue, with alarming implications for overall health and well-being.

“Magnesium is involved in over 600 bodily functions”

The current recommended daily allowance (RDA) only allows you to avoid  a deficiency that leads to a health condition and not to optimise that mineral. The RDA for magnesium stands at around 400 mg/day for a healthy adult.

However, data from a large US national survey reveal that the average magnesium intake falls short of this mark, with women consuming approximately 230 mg/day and men around 320 mg/day. You are only able to absorb around one third of the magnesium in your food [1]. The minerals are absorbed from the soil the plants are grown in, with there In just the last 70 to 80 years, the micronutrient content of food has rapidly declined.

Plants get their nutrients from the soil and animals get their nutrients from plants. Thus, the more nutrient depleted the soil is, the fewer nutrients the vegetation growing on it will have. The food that we now eat is about 30% less nutritious than the same food from 1940. That means you would need to eat 30% more food to get the same level of minerals that someone used to get who lived just 80 years ago [2].

Meeting the RDA only provides the bare minimum to prevent severe diseases associated with magnesium deficiency.

plant seedling

Where is Magnesium stored in the body?

About 99% of the body's magnesium is in bone, muscles, and soft tissue, with only 1% found in plasma and red blood cells [1]. This dispersion means that deficiencies can wreak havoc on various bodily systems, ranging from musculoskeletal issues to cardiovascular complications.

It underscores the importance of not only meeting but exceeding the recommended intake levels to safeguard against the myriad consequences of deficiency.

Addressing this issue requires a multifaceted approach, including dietary adjustments, supplementation when necessary, and increased awareness of magnesium's critical role in maintaining overall health. By understanding the reasons why we lose magnesium and how we can optimise magnesium intake will address the deficiency proactively, to help mitigate the risks associated with inadequate magnesium levels and optimise their well-being for the long term.

Top Three Reasons Why Many People Are Lacking Magnesium

Reason #1: Low intake of foods rich in magnesium (such as green leafy vegetables containing chlorophyll)

Magnesium, a vital mineral for various bodily functions, and is abundantly found in green leafy vegetables due to its presence in chlorophyll. Today, we choose that are abundant in energy but lacking in density of micronutrients. This dietary pattern is a significant driver of magnesium deficiency, highlighting the importance of incorporating magnesium-rich foods like:

  • Spinach - 78mg in a ½ cup.

  • Almonds - 78mg in 1 ounce (23 almonds).

  • Lima Beans - 63mg in a ½ cup.

  • Oat bran - 96mg in a ½ cup.

  • Brown Rice - 86mg in a ½ cup.

Low-Magnesium foods that are highly consumed:

  • Milk

  • Meat 

  • White flour

Do we need more of these greens or not? More on this next!

spinach magnesium source

Reason #2: Poor intestinal absorption of minerals

Even when individuals consume magnesium-rich foods, their bodies may struggle to absorb an adequate amount due to various factors affecting intestinal absorption [3].

“Only around 1/3 of the Magnesium from our diets is absorbed.”

Alkaline conditions in the intestines, common in diets high in processed foods, can hinder mineral absorption, including magnesium. 

Despite oat bran and brown rice being rich in magnesium, they are not the ideal sources due to poor absorption. The magnesium in these foods is bound to phytates, reducing its bioavailability. Humans cannot digest phytates, leading to impaired absorption of minerals, including magnesium and zinc. Additionally, high-dose supplementation of other minerals like zinc can compete with magnesium for absorption, further hindering its uptake. For instance, high doses of zinc have been found to inhibit magnesium absorption, highlighting the complexities of mineral interactions in the body.

This underscores the importance of not only consuming magnesium-rich foods but also ensuring optimal conditions for absorption.

Reason #3: Excessive excretion of minerals

The body tightly regulates magnesium levels, primarily through the kidneys, which reabsorb approximately 95% of filtered magnesium to prevent deficiency. However, certain factors can disrupt this balance, leading to excessive excretion of magnesium. 

Several factors can greatly impact the reabsorption process of Magnesium in the kidney:  

  • Alcohol consumption, common in many societies, doubles the rate of magnesium excretion

  • Type 1 & 2 diabetes mellitus can also increase magnesium loss.

  • Gastrointestinal problems - Crohn's disease, Irritable Bowel Disease, etc. can increase the secretion of magnesium into the faeces. 

  • Excessive sweating can further contribute to magnesium depletion, highlighting the importance of addressing these factors to maintain optimal magnesium levels.

Can an active lifestyle affect Magnesium levels?

Active lifestyles can increase the body's need for magnesium. While the recommended intake varies by age, sex, and life stage, those engaged in regular physical activity may require up to 20% more magnesium due to increased loss through sweat and stress. This heightened requirement underscores magnesium's critical role in muscle function, energy metabolism, and maintaining electrolyte balance, essential for athletic performance and recovery.

Determining magnesium levels can be challenging, as much of the body's magnesium is stored in bones and muscles. Blood tests may not accurately reflect magnesium status, making dietary tracking essential. Consuming magnesium-rich foods like leafy greens, nuts, seeds, and legumes, alongside appropriate supplementation, can help meet individual needs.

“My best nut and seed choices for Magnesium would be Cashews, Brazil and Pumpkin Seeds."

healthy seeds and nuts magnesium

How to choose the correct Magnesium supplement?

When supplementing, choosing the right form of magnesium is crucial. Salts like magnesium glycinate and malate offer superior bioavailability and are gentler on the digestive system, contributing significantly to daily magnesium requirements. Smaller, more frequent doses may provide the greatest benefits and if the magnesium is dispersed in water, that is the best for absorption. In fact, it can increase absorption by 40% of the magnesium when consumed in water in smaller equal amounts.

A Summary on Magnesium Deficiency

Magnesium deficiency has implications for cancer risk, as it affects critical biological processes like DNA repair. Adequate magnesium intake supports bone health, cardiovascular wellness, and overall longevity. Therefore, achieving optimal health necessitates sufficient magnesium intake through a balanced diet and supplementation regimen.

Understanding these three primary reasons for magnesium deficiency is crucial for implementing effective strategies to combat it. From dietary modifications to lifestyle changes, prioritising magnesium intake can have profound implications for overall health and well-being. By recognizing the importance of magnesium and taking proactive steps to ensure adequate intake, individuals can safeguard themselves against the detrimental effects of deficiency and promote long-term health and vitality.


  1. Jahnen-Dechent W, Ketteler M. Magnesium basics. Clin Kidney J. 2012 Feb;5(Suppl 1):i3-i14. doi: 10.1093/ndtplus/sfr163. PMID: 26069819; PMCID: PMC4455825.

  2. DiNicolantonio, James. The Salt Fix: Why the Experts Got it All Wrong and How Eating More Might Save Your Life (p. 22). Little, Brown Book Group. Kindle Edition.

  3. Adam A, Lopez HW, Tressol JC, Leuillet M, Demigné C, Rémésy C. Impact of whole wheat flour and its milling fractions on the cecal fermentations and the plasma and liver lipids in rats. J Agric Food Chem. 2002 Oct 23;50(22):6557-62. doi: 10.1021/jf020418b. PMID: 12381149.


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