Magnesium supplements work well for those who are deficient or have low levels in their diet. Unfortunately, decades of intensive farming have depleted Irish soils of many essential nutrients, meaning produce is often less nutritious than it used to be.
As many as 70% of adults do not get enough magnesium daily . Supplements may help address signs of deficiency and provide additional benefits.
In the guide below, we discuss further the main functions of magnesium, how they work, and key health benefits of taking supplements.
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Essential Functions of Magnesium
Magnesium is the fourth most abundant mineral in the body and is a cofactor in over 300 enzymes. It is also the most commonly under-consumed in the modern Irish diet. One reason for this is that 20% of soils are deficient in magnesium, reducing the amount present in everyday foods.
Magnesium has been formally recognised as essential for the following processes and systems:
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Normal muscle function : Without enough magnesium, muscles are unable to fully relax, which can contribute to cramps. This applies to the muscles in the blood vessels and heart too.
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Nervous system and psychological: When magnesium levels are adequate, it dampens excessive nerve stimulation – essentially acting as a ‘brake’ for the nervous system.
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Energy-yielding metabolism and the reduction of tiredness and fatigue
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Maintenance of normal bones and teeth: Without sufficient magnesium, vitamin D cannot be converted into its active form, thereby limiting its availability.
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Normal electrolyte balance
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Normal protein synthesis
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Cell division: Which is essential for growth and recovery.
How magnesium supplements work
Magnesium supplements are designed to treat low levels (hypomagnesaemia), but serum levels (in the blood) are not a good indication of magnesium levels; only 1% of magnesium is found in the blood.
Magnesium passes both actively and passively into cells, with the majority stored in the bones and soft tissues.
Absorption and bioavailability explained
Normally, the body absorbs 30-40% of the magnesium ingested from food or supplements, but this largely depends on the form. It takes between 1-6 hours to absorb most of the magnesium from dietary sources. This means that the timing of magnesium supplementation can be important but may not be critical for its effectiveness.
Once absorbed into the body, the kidneys fine-tune magnesium levels, excreting excess amounts into the bowels. This mechanism is behind its laxative effects.
Factors affecting magnesium uptake
Once ingested, stomach acid breaks down the compounds bound to magnesium, releasing magnesium ions (this depends on the type of magnesium). It is absorbed via passive and active transport. The following factors can affect bioavailability and the rate of absorption.
● The type and bioavailability of magnesium : inorganic salts may be less bioavailable
● A high calcium intake : competes for active transport
● Low stomach acid levels
● Gastrointestinal issues such as Crohn’s, coeliac disease, or IBD
● Kidney disease
● Type 2 diabetes
● Certain medications (speak to a medical professional about medication interactions)
Certain factors enhance absorption, such as vitamin D supplementation. Low levels of stomach acid (more common with age or those who take acid reflux medication) and high calcium intake may also limit magnesium uptake, as they compete for active transport.
How do the different types of magnesium work in the body?
The form of magnesium in a supplement matters because it affects how efficiently the magnesium is absorbed, how well it is tolerated, and whether the companion molecule it is bound to provides any additional benefits
Magnesium glycinate
Magnesium glycinate is magnesium bound to glycine, a naturally occurring amino acid. It is widely tolerated and highly bioavailable. Amino acid chelates like glycinate can be easily taken up in the intestines. Glycine is itself a calming, inhibitory neurotransmitter which can support the calming effects of magnesium.
3: Magnesium citrate
Magnesium citrate is magnesium bound to citric acid. It is highly water-soluble, bioavailable and well-tolerated, but it has mild laxative effects.
Shop our entire collection of magnesium citrate supplements at Meaghers Pharmacy here.
Other forms of magnesium
The cheapest forms of magnesium are inorganic magnesium salts such as magnesium oxide, magnesium carbonate, or magnesium sulphate. These are poorly absorbed despite having a high proportion of elemental magnesium.
Other chelated forms of magnesium include magnesium malate, magnesium taurate, and magnesium L-threonate. These organic forms are highly bioavailable and may have additional benefits, such as supporting energy-yielding metabolism (malic acid), cognitive function (L-threonate), and circulatory health (taurine).
Health benefits of taking magnesium supplements
● Sleep : magnesium is necessary for activating the ‘rest and digest’ pathway. There is also an association between poor sleep and low magnesium levels.
● Stress & anxiety : one study found that supplementation with magnesium glycinate improved subjective well-being.
● Muscle cramps : muscle cramps and restless leg syndrome are strongly associated with magnesium deficiency.
● Blood pressure : magnesium supplementation has a mild effect on reducing blood pressure.
● Relaxation: magnesium supports the sympathetic nervous system (rest-and-digest); balanced levels help maintain proper nervous system function.
Learn more about the benefits of magnesium supplements for different uses with our comprehensive guide here.
Does magnesium work for everyone?
If a person's magnesium levels are already balanced, supplementation is less likely to produce noticeable benefits. This is because the kidneys are efficient at excreting excess magnesium; the body simply removes what it does not need. Unlike vitamin D or iron, the effects of magnesium top-up in people who are not deficient are generally subtle.
Consider magnesium supplementation for the following:
● Treating a known deficiency
● Treating symptoms strongly associated with magnesium deficiency
● Supporting a slightly elevated blood pressure
● Supporting an active lifestyle
● Supporting sleep quality and stress management
Frequently Asked Questions:
How quickly do magnesium supplements work?
It takes around 10 days for magnesium levels to build up in the body if they are low. However, you may notice short-term effects depending on the type you take.
What is the recommended effective dosage?
Adults need around 400mg of magnesium per day from their diet and supplements combined, but the amount actually absorbed can depend on the form taken.
Are there any side effects of magnesium supplements?
Magnesium supplements are generally safe and effective when taken at the recommended dosage. Healthy kidneys are efficient at getting rid of excess minerals, but pay attention to signs of hypermagnesemia if you accidentally take more than the recommended amount.
