A recent news-feed included an “important article report”, from the Neuroimaging and Brain Lab at the Australian National University (ANU).
Entitled “A higher dose of magnesium each day keeps dementia at bay”, the report states that the brain age of people consuming more than 550mg of magnesium (Mg) daily is approximately one year younger at age 55, than that of people with a normal Mg intake of about 350mg per day.

The article, “Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences“,DOI: 10.1007/s00394-023-03123-x, by  Khawlah Alateeq, Erin Walsh and Nicolas Cherbuin, was published by Research Gate on 3/10/23 and reported by,  NIH and the European Journal of Nutrition.
It involved more than 6,000 cognitively healthy subjects in the UK, aged 40-73 and it
concluded that higher dietary Mg intake is related to better brain health in the general population, particularly in women.

An important mineral

This article reminded me that magnesium is of prime importance in our bodies and as such, deserves a place in this blog.
Magnesium is a major constituent in many grains, fruits and nuts (especially, almonds); but because the fields on which our food is grown have become magnesium deficient over time, deficiency is very common in humans: anyone who has constipation and (or) muscle cramps is probably either hypothyroid, or short of magnesium.

An essential nutrient

Magnesium is an essential nutrient for normal body functions.
After potassium, Magnesium is the second most common metal in the cells: half is stored in bone, with less than 1% in body fluids.
The blood contains only 0.3% of the total body magnesium and interestingly, the concentration of magnesium in the brain is much higher than it is in the blood.

A very active factor

Mg is involved in about 350 biochemical processes (80% of body processes), and activates many intracellular enzymes.
It is important for protein synthesis, membrane stabilization, antibody activity and immune response.
It helps to build strong bones, but paradoxically, is active in preventing calcification of arteries and in removal of calcium from their lining in cases of arteriosclerosis.   

Magnesium deficiency

In young people, the small intestine absorbs 30–50% of the Mg intake, but the percentage diminishes in old age, chronic Kidney disease and increasing intake.
Also, the magnesium content of farm soils has been eroded over time due to intensive cultivation of crops without replacement of the metal.
In any event, Mg deficiency is endemic, so the symptoms and signs of low magnesium are common.

Conditions due to magnesium deficiency

High blood pressure, arteriosclerosis, heart disease, diabetes, osteoporosis and bone fractures, migraine, asthma, constipation and chronic kidney disease, fatigue, tiredness and weakness are associated with low magnesium.

The commonest complaints are:

Constipation: calcium is necessary for muscle contraction and magnesium, for muscle relaxation. So if the Mg is low, the muscles of the large intestine are unable to relax, to accept bowel contents coming from above. Therefore movement of stool towards the rectum slows down, water absorption by the lower bowel (the sigmoid colon) dries it out and the waste becomes very difficult to move.

Muscle cramps: although magnesium deficiency has been blamed for muscle cramps, no direct association has been proven and taking Mg does not necessarily prevent cramping.

Vascular calcification (VC, arteriosclerosis), commoner in patients with chronic kidney disease (CKD) and especially in those on dialysis, contributes to the risk of cardiovascular disease (CVD).
Under certain circumstances, calcium and phosphate concentrations in the circulation become supersaturated. They then combine with blood proteins, to form “calciprotein” particles (CPPs), which pass through the lining of the arteries and enter the muscle cells. This is not a simple precipitation of excess calcium and phosphate: it is an active process, ending with transformation of the vascular smooth muscle cells (VSMCs) into osteoblast-like (bone–forming) cells.
Until recently, management of hyperphosphatemia and avoidance of calcium overload have been the major strategies for preventing its progression, but adding magnesium is the best idea.
Magnesium inhibits the maturation of CPPs by substituting for calcium ions: if there isn’t enough Mg, the result is stiffening and narrowing the arterial walls, with muscle pain (“claudication”), due to the reduced blood supply.
Claudication is usually felt in the legs, but can affect the thighs and buttocks.
It is a sure sign of arteriosclerosis and is a warning of an impending heart attack.

Hip fracture: lower serum Mg levels are associated with an increased risk of fractures: the assessment for osteoporosis should include checking magnesium levels and part of the treatment should be Mg supplementation.

Poor response to brain injury: Brain swelling from injury and in neurological diseases is associated with low Cerebral Mg concentration: giving magnesium reduces brain swelling, restores the ability of the blood-brain barrier to keep toxins out and improves the speed and efficiency of healing. It may be that in brain injury and neurological diseases, a low Mg level is part of the reason for brain swelling and slow recovery.

Mg as therapy

Magnesium is recommended for treatment of constipation, muscle cramps, migraine, asthma, depression, anxiety, diabetes, high blood pressure, atrial fibrillation, insomnia, chronic fatigue, dementia, osteoporosis, fibromyalgia, chronic pain, constipation, brain injury, cerebral palsy, stroke and brain haemorrhage.

Therapeutic protocol

If low blood magnesium (“hypomagnesmia”) is the result of failed absorption of Mg due to bowel disease, treatment should begin with management of the bowel issues; but regardless of the reasons for the deficiency, Magnesium levels should be restored by mouth, intravenously or by intramuscular injection.
If given by mouth, it is better taken at night, because it promotes sleep: it should be taken with progesterone and melatonin, because progesterone (reliably converted to Allopregnanolone), magnesium and melatonin work together to maintain brain cells and repair oxidative and inflammatory damage to their axons and dendrites.

The recommended daily allowance of elemental magnesium is 320-420mg/day.
The recommended magnesium “salts” are the citrate, chloride, sulphate, gluconate, acetate, lactate, threonate and bisglycinate.
Magnesium oxide is more often used as a laxative, although it can be buffered, to make it more soluble and absorbable.

Magnesium Bisglycinate (buffered) and Threonate are theoretically best: they are more easily absorbed and cross the blood-brain barrier more reliably.
However magnesium citrate, the least expensive, works well (a popular magnesium citrate preparation, “Calm Mg”, is for some reason, expensive).


Magnesium oversupply in the blood (hypermagnesemia), due to taking too much supplement, is unusual in healthy people: an overdose is usually lost as diarrhea
(if you develop loose stool, you’re taking too much) and hyper-absorption is automatically corrected by excretion of magnesium in the urine.
Some types of kidney disease can result in reduced magnesium excretion: an increased blood magnesium level used to be a serious concern among CKD patients with decreased urinary Mg excretion. However recent epidemiologic studies have found that lower Mg concentrations bring an elevated risk of all-cause and cardiovascular mortality among hemodialysis patients: those with a slightly elevated magnesium level tend to survive longer (this is interesting and hasn’t as yet been explained).

Magnesium deficiency and chronic kidney disease (CKD)

In a page in Clinical and Experimental Nephrology volume 26, pages 379–384 (2022), Published: 25 January 2022, by Yusuke Sakaguchi, entitled “The emerging role of magnesium in CKD”, Dr. Sakaguchi concluded that magnesium is essential to preservation of kidney function and prevention of arteriosclerosis: below, see an excerpt from Dr. Sakaguchi’s notes (paraphrased, for brevity).
”Vascular calcification is a serious complication of chronic kidney disease and the current therapeutic strategy is insufficient for preventing its progression.
Magnesium, a potent inhibitor of calcification, is a promising therapeutic candidate.
Diaz-Tocados and colleagues demonstrate that Mg prevents vascular calcification, independently of the phosphate-binding capacity.”

The bottom line

In brief: magnesium, a very important mineral in its own right and in particular, an antidote to arteriosclerosis, is essential to a long and healthy life.
It is often deficient due to poor diet, or to Mg loss in kidney disease.
Supplementing it, between 150 and 600 mg daily, is necessary for many.
Overdose is unlikely: if too much is ingested, it is lost in diarrhea. Chronic kidney disease may cause high Mg levels, but no harm ensues.


[1] Alateeq K, Walsh EI, Cherbuin N. Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences. Eur J Nutr. 2023 Aug;62(5):2039-2051. doi: 10.1007/s00394-023-03123-x. Epub 2023 Mar 10. PMID: 36899275; PMCID:

[2] Wu Z, Ruan Z, Liang G, Wang X, Wu J, & Wang B (2023). Association between dietary magnesium intake and peripheral arterial disease: Results from NHANES 1999–2004. PLOS ONE18(8), e0289973. doi: 10.1371/journal.pone.0289973.

[3] Sakaguchi Y. The emerging role of magnesium in CKD. Clin Exp Nephrol. 2022 May;26(5):379-384. doi: 10.1007/s10157-022-02182-4. Epub 2022 Jan 25. PMID: 35076791; PMCID: PMC9012765.