Shaun Ward MSc ANutr
Magnesium (Mg) is the fourth most common mineral in the human body and is undoubtedly an important electrolyte for human metabolism.
Around about 50% of magnesium is stored in our bones, with the remaining 30% stored in muscle, 20% in other soft tissue, and <1% in blood.
The presence of Mg is essential in over 300 enzyme systems. These enzymatic reactions are necessary for the functioning of protein synthesis, muscle contraction, nerve function, blood glucose control, nucleic acid synthesis (DNA/RNA), hormonal activity, blood pressure regulation, among others.
Magnesium is also heavily involved in energy production and is the reason why intracellular magnesium is highly concentrated in the mitochondria – an energy-producing organelle .
Below we have rounded up the primary benefits that are supported by credible scientific research:
1. It's Good For Supporting Bone Density
We've all heard that getting plenty of vitamin D and calcium is important for having strong and healthy bones, but there's not a whole lot of noise around the importance of Magnesium for supporting bone strength.
It's a reasonably well-kept secret that magnesium can help enable the successful conversion and activation of vitamin D into its bioactive form - this essentially means that it's important for ensuring the Vitamin D you consume is as effective as it can be.
As vitamin D is critical for aiding the absorption of calcium – crucial for bone health – it is clear to see how the mineral has an indirect knock-on effect for helping bone metabolism.
One study conducted on 2038 elderly participants (african and caucasian men and women between the ages of 70-79) looked at the association between magnesium intake and bone mineral density. The results found that the caucasian participants who had greater levels of magnesium in their diet demonstrated a higher bone mineral density on average.
In turn the study concluded that higher dietary magnesium intakes are associated with higher bone mineral densities .
Similarly, magnesium supplementation has shown to suppress bone turnover rates. A study conducted on 12 men between the ages of 27-37 showed that a daily oral dose of 15 mmol Mg for 30 days reduced the biochemical markers of bone turnover, which supports the theory that Magnesium can actually prevent bone loss, especially for those with age-related osteoporosis .
Not only does bone health improve from higher intakes, but there is also evidence that this results in fewer bone fractures too .
2. Better Cardiovascular Function & Heart Health
Scientific reviews have found that sufficient intake significantly lowers the risk of cardiovascular disease, most notably for ischemic heart disease .
In addition, individuals with blood magnesium concentrations in the highest quartile of the normal physiological range have a ~40% lower risk of sudden cardiac death compared with those in the lowest quartile .
Appropriate magnesium intakes contribute to reducing mineral and fatty deposits on vascular walls, that would otherwise form arterial plaques. This prevents the narrowing of the arteries and helps avoids atherosclerosis.
Another potential cardiovascular benefit of magnesium is that it can induce direct and indirect vasodilation – widening of blood vessels – that could prevent against arterial constriction .
There may also be a role for magnesium increasing the amount of cholesterol transported to the liver from arterial walls by HDL (“good” cholesterol) .
3. Associated With Lower Rates of Diabetes
Studies conclude that there is an inverse association between magnesium and the incidence of type 2 diabetes. Specifically, consuming the recommended daily intake lowers the overall relative risk for type 2 diabetes by 15% .
It’s role in preventing diabetes is likely due to its function in improving glucose and insulin metabolism, mainly through its impact on the activity of insulin receptors.
It may also improve insulin sensitivity – cell responsiveness to insulin production - by increasing the activity of proteins that facilitate the transport of glucose across cell walls and thereby upregulating glucose uptake .
4. It Can Help Support Athletic Performance
Another reason to ensure you're consuming this electrolyte is because it can be beneficial for those who are looking to give themselves a physical and mental edge during athletic performance (this can be a competitive sport or just a plain old gym workout).
A Study into magnesium has shown that it helps enhance muscle glucose levels, which can help extend your endurance. Furthermore the same study showed it also helped prevent lactic acid buildup within the muscle. Not only this, but it also enhances brain glucose levels, which may also help produce mild nootropic-like effects (i.e. it can improve cognition). 
With so much hype around it being useful for athletic performance (think of the buzz surrounding ZMA supplements for example), it won't be too surprising to learn that there have been multiple clinical trials conducted directly on athletes themselves.
One study involving a group of 24 Brazilian athletes showed that 2g of Mg Sulfate (delivered via IV) every two days for improved strength and inspiratory capacity. 
Another study showed that magnesium improved the endurance levels in 23 competitive triathletes when compared to the group that were given a placebo. 
Finally, a study that gave 25 male volleyball players 350mg of Magnesium per day found that players experienced an improved ability to squat jump, countermovement jump and countermovement jump with arm swing - it was noted that none of the players were deficient prior to the test, which is very positive. 
5. It Has Been Shown To Be A Natural Anti-Depressant
Most people know that magnesium is a highly important mineral for supporting brain health, but not a lot of people know that it also can play a role in keeping your mental health in good standing too.
The first initial studies into using the mineral to improve agitated depression were published over 100 years ago, since then there have been numerous different studies further investigating what it is truly capable of.
One of the biggest pieces of research was conducted between 2007 - 2010 on 8894 US adults (4215 men and 4679 women) with an average age of 41 years old. The study looked at the relationship between the individuals' average daily magnesium intake and compared it to their PHQ-9 results (PHQ-9 being a medical questionnaire that helps doctors establish the degree of depression severity). The results showed that those with the lowest magnesium intake showed a higher degree of depression severity on average. 
We found a significant association between very low magnesium intake and depression, especially in younger adults.
- Tarleton EK & Littenberg B, 2015.
Scientists aren't fully sure why magnesium seems to have anti-depressant qualities, they suspect it's due to it influencing "several systems associated with development of depression". 
While most studies are positive, it's not cut and dried - a systematic review into magnesium and depression stated that further investigation is needed to conclusively state whether or not it really can be effective for treating mental health disorders. 
It Shouldn't Be Used As A Replacement For Anti-Depressant Medications
The study clearly stated that it could be useful when used alongside prescribed medications; it is stressed that it shouldn't be used as an alternative.
6. It May Be Useful For Those With Hypertension
High blood pressure is a silent killer - it's symptomless and claims the lives of 1100 americans every single day! Luckily, there's credible scientific evidence showing that magnesium can be help treat hypertension (high blood pressure).
One study that gave 24 participants with "mild hypertension" 600mg of magnesium each day (along with "lifestyle recommendations") showed a small but consistent reduction in blood pressure over a period of 12 weeks. 
Another study conducted in 1998 investigated the mineral's impact on blood pressure levels on 60 participants (men and women aged between 33-74 years old) showed similar results - a small but consistent reduction over the 8 weeks of the study. 
Useful For Hypertension - Not For Lowering Blood Pressure In General
You'll note that we've only stated it's "useful for those with hypertension" - this is because one major study has shown that the blood pressure reducing properties of the mineral seems to only occur for those who have a high blood pressure - if you have a normal blood pressure, it is unlikely to lower it beyond your normal healthy threshold. 
7. It's Good For Those Who Suffer From Migraines
A migraine can be completely debilitating and can often be a semi-regular occurrence for certain individuals. When scientists investigated similarity founds in migraine-sufferers, they found may appeared to be magnesium deficient. 
It is believed that having a deficiency may, among other things, promote "cortical spreading depression" - a slow-moving wave of depolarization that slowly spreads through the brain that can trigger the trigeminal nerve into causing pain.
One study that used oral administrations of magnesium to treat migraines in 86 children between the ages of 3-17 showed that the "treatment..did lead to a significant reduction in headache days" when compared to the placebo group. 
Another study gave 600mg of magnesium each day to 30 participants between the ages of 20-55 years old for 90 days. Results showed that migraine attack frequency was "significantly lower" when compared to the placebo group. 
Based on the average western diet, standard intakes are currently only reaching 30%-50% of the recommended daily amounts.
It is also estimated that over 50% of people do not regularly consume adequate amounts of magnesium in their diet .
The high prevalence of magnesium deficiency is mainly because unprocessed, nutrient-rich foods are being replaced with processed, low nutrient foods.
However, even whole-foods now have reduced magnesium contents from modern agricultural farming methods such as the use of pesticides and soil depletion.
Other dietary factors also influence magnesium absorption, such as low vitamin D concentrations, alcohol use, or interactions with common medications - antibiotics, antacids, and hypertensive drugs.
Common symptoms of deficiency include:
- Loss of appetite.
More pronounced symptoms of deficiency are:
- Increased neuromuscular irritabilities such as spasms, tremors, muscle cramps, and seizures.
Magnesium Sources and Bioavailability
Below, we've listed the best food sources of Mg per 100 grams:
- Hemp seeds.
- Pumpkin seeds.
- Flax seeds.
- Brazil nuts.
- Whole grains.
- Kidney beans.
Tap, mineral, and bottled waters can also be sources of magnesium, but the amount of magnesium in water varies by source and brand (ranging from 1mg/L - 120mg/L).
However, it is important to be aware that phytic acid contained within nuts, seeds, and grains, is a natural chelator that diminishes the absorption of certain minerals including magnesium.
This reduced absorption is exaggerated further if the crops were treated with glyphosate – a pesticide agent that also chelates minerals.
In accordance, the bioavailability of magnesium in these food sources is significantly low. Overall dietary bioavailability of magnesium is 30%-40% .
Supplementation is a convenient and safe method to increase magnesium intakes from a highly bioavailable source.
Supplements should be sourced from either magnesium chloride, lactate, aspartate, or citrate, as these are highly bioavailable . We recommend that you avoid low bioavailable supplemental sources such as magnesium oxide.
If you feel like you're not consuming enough of this wonder-mineral, then you shouldn't delay on increasing your daily intake (which can often be as simple as adding a simple magnesium supplement into your daily routine).
Most people do not regularly consume adequate amounts in their diet to meet the recommended daily intake number, and this can cause your general health to suffer - it may also lead to side effects such as the loss of appetite, lethargy, nausea, mental health issues, and major neuromuscular irritabilities.
It is an extremely important electrolyte for human metabolism and is required for functions such as protein synthesis, muscle contraction, nerve function, blood glucose control, and DNA and RNA synthesis.
Adequate intake has been scientifically shown to:
- Help promote bone health - by increasing bone mineral density and the uptake of calcium and vitamin D.
- Support better cardiovascular function - by lowering your risk of sudden cardiac death by a massive 40%.
- Lower the likelihood that you'll get diabetes - by helping your body better process glucose (sugar) and insulin.
- Improve your physical and mental performance - by pushing more glucose into your muscles and brain.
- Improve your mental health - by supporting optimal brain function.
- Lower blood pressure for those who have a high blood pressure - by helping prevent blood vessels from constricting.
- Reduce the likelihood of migraines - by preventing cortical spreading depression.
Good dietary sources are seeds, beans, legumes, wholegrains, green leafy vegetables, and fish. However, the bioavailability of magnesium is low in most foods due to the presence of phytic acid.
It is recommended to consume 400mg or 310mg per day for men and women, respectively. These recommended intakes are slightly increased for the elderly or pregnant women.