Magnesium

The old saying “you are what you eat” is becoming increasingly important in many aspects of health and medicine.

Magnesium is a cofactor of many enzymes and is involved numerous cellular functions. It is needed for normal nerve and muscle function and has a central role in both glucose metabolism and in how energy works in the body. Over 300 enzymes require the presence of magnesium ions for their action – this includes all the enzymes that use of make ATP, which is the body’s energy molecule. Other uses include making both DNA and RNA. There is also an important interaction between phosphate and magnesium, so magnesium is essential to the basic nucleic acid chemistry of life, and thus is essential to all cells of all known living organisms.

Obtained from food, the highest sources are green vegetables (plants make chlorophyll – the green pigment – with magnesium). Examples are leafy vegetables, such as spinach, broccoli, rocket, and parsley. Other good sources are from foods that contain good amounts dietary fibre, such as legumes [black beans and edamame], nuts [e.g., almonds], seeds [especially pumpkin kernels], and whole grains (see below for a list). Some types of food processing, such as refining of grains and the removal of germ and bran, lower magnesium content substantially [1].  

Magnesium is absorbed in the small intestine – just how much is absorbed is influenced by the type of magnesium, your transit time (how quickly food moves through your digestive tract), protein intake as well as intake of phosphate, phytates and fat. Excretion in the urine is the usual route out of the body except when intakes are very high, when it may also be excreted in the faeces (your poop).

An adult has about 24 grams of magnesium in their body, with 2/3 of it in the skeleton, just under 20% muscles and only small amounts outside of the cells, including in the blood stream. Because of this, levels in the blood are not representative of true total body magnesium stores.

Magnesium is involved in the formation of phospholipids which are required for the outside layer of every cell and have a vital role in the function of both skeletal, cardiac and other smooth muscles.

When magnesium levels are low several different symptoms can occur. These include lethargy, weakness, tremors, leg or foot cramps, premenstrual syndrome, headaches, cold hands or feet, depression, and when severe, low magnesium can lead to seizures, hallucinations, altered sensation, delirium, irregular heart beat and congestive heart failure. Excessive magnesium is very rare and is usually related to kidney failure, chronic diarrhoea or overuse of laxatives or antacid drugs [2].

LEARNING & MEMORY

Magnesium is very important in normal cellular function and the field of neuroscience doesn’t escape this effect. There is mounting evidence that nutritional factors, including magnesium adequacy play a major role in cognitive status, or cognitive wellbeing. A study using rats showed that just 14 days of magnesium deficiency impairs how quickly a new task can be learned. Supplementation with specific types of magnesium result in an enhancement of various forms of cognitive/ learning ability, including working memory [6].

Blood Sugar Management

Supplemental magnesium has been demonstrated to significantly improve the marker used to monitor blood glucose levels (HbA1C), as well as other markers of insulin resistance, in particular blood insulin levels, C-peptide, HOMA.IR and HOMA.β%, as well as a slight reduction in fasting blood sugar levels. In addition, the use of Mg supplements reduced insulin resistance and improved glycaemic control indicators among people with type 2 diabetes [Ref].

How Much Magnesium Should I be Getting?

RECOMMENDED DAILY INTAKE

Adult women typically need at least 300-350 mg per day, and men 400-420 mg, though this varies according to health status and other factors.

You typically absorb between 30% and 40% of the magnesium you consume.

For many people, this simply isn’t enough – see the factors above that may mean you need more magnesium than the RDI.

Can I get too much?

The short answer is YES. But there are many different forms of magnesium, and each has different “strong points” and absorption capacity. In general, too much magnesium is likely to cause loose bowels and may also trigger nausea and abdominal cramps. The types most commonly reported to cause diarrhoea include magnesium carbonate, chloride, gluconate, and oxide, which happens due to the non-absorbed mineral “pulling” (by osmosis) water into the gut, which stimulates contractions of the intestines. 

However, if your blood level gets too high, you may develop hypermagnesaemia , with symptoms such as feeling faint (from low blood pressure), nausea, vomiting, lethargy, and erratic heartbeat. Those most at risk of hypermagnesaemia are those with kidney problems.[Ref]

What is the Best Form of Magnesium to Take?

The answer depends on why you need extra magnesium. If you want to use it as part of a strategy to manage constipation, then the less-well absorbed forms (such as oxide and sulphate) are ideal, such as in this product.

Generally, those that dissolve well in liquid are more completely absorbed. Small studies have found that the aspartate, citrate, lactate, and chloride forms are absorbed more completely and are more bioavailable.

1. 1. Magnesium aspartate. This is a mixture of aspartic acid and magnesium. This may be one of the easier-to-absorb forms, but 100mg of Mg asparate gives you just 20mg of the magnesium Read the research
   2. Magnesium chloride. Bound with chloride, this form can be extracted from seawater. It is variable in it’s boosting power. Great in the bath or as a food soak.
   3. Magnesium citrate. Bound with citric acid, naturally found in citrus fruits, this is a widely utilised type of magnesium – mainly because it quite bioavailable and absorbable. Often available in powder form, so it dissolves readily into liquid, making it easier to absorb. Mag citrate may also be used to stimulate bowel function, soften stool.
   4. Magnesium glycinate. The amino acid glycine has a number of different functions. It acts as a neurotransmitter, is incorporated into collagen, but importantly, it is used to produce glutathione, a powerful antioxidant, which helps protect your cells against oxidative stress. Glycine is also helpful in getting a good night’s sleep.  Roughly 2000mg of Mag glycinate is needed to get 200mg of magnesium.
   5. Magnesium L-threonate. Recent advances have demonstrated that this form is superior for supporting cognitive function, mental clarity and focus and general brain health.
   6. Magnesium malate.Great for those who cannot take other forms of magnesium, the malic acid may aid general bodily comfort. Other uses are for optimal muscle function as well as supporting stress response, healthy sleep cycle, good cardiovascular health and energy. Malic acid may also provide support for general bodily comfort.te
   7. Magnesium oxide. Used to make Milk of Magnesia, this form is popular in constipation remedies.
   8. Magnesium sulphate. This poorly absorbed form is best used for treating constipation, or in the bath (it’s what makes up Epsoms salts). If you have sensitivities to sulphur, this form is best avoided.
   9. Magnesium taurate. Possibly one of the more expensive forms, but the conjugation to taurine (an amino acid) makes it stand out for use in those with problems managing blood sugar levels and in helping regulate elevated blood pressure.

Note that high-dose magnesium supplementation may increase your need for calcium. Also, high doses of zinc from supplements (over 100 mg/day) can interfere with intestinal absorption and disrupt your body’s balance of minerals, including magnesium.

Food Sources of Magnesium

REFERENCES

[1] https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/

[2] https://www.ncbi.nlm.nih.gov/books/NBK507271/

[3] https://www.ncbi.nlm.nih.gov/pubmed/12958403

[4] https://www.ncbi.nlm.nih.gov/pubmed/31646259

[5] https://www.ncbi.nlm.nih.gov/books/NBK507250/

[6] Magnesium in the Central Nervous System [Internet]. University of Adelaide Press; 2011. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507271/