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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 foods that contain dietary fibre. Other good sources are green leafy vegetables, such as spinach, legumes, nuts, seeds, and whole grains. 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 gastrointestinal tract, but absorption is affected by protein intake as well as phosphate, phytate and fat. Excretion in the urine is the usual route out of the body except when intakes are very high, when it may be excreted in the faeces.

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].


One study looked at levels of toxins and minerals in the hair and blood of women with PMS and compared their levels with those of women without PMS [3].

They found the levels of calcium in the blood cells of patients with PMS was lower, and the ratios of magnesium: calcium much higher, but in hair these ratios were reversed. This implies that the interaction of calcium and magnesium might be important than either alone, especially in women with PMS. A more recent study has suggested that it is deficiency in vitamin D to be the main driver of PMS symptoms [4]. Interestingly, low vitamin D increases the risk of low blood calcium, so magnesium and calcium get out of balance. Contact us to get your vitamin D tested.


A study in 1997 examined 116 children with ADHD and found that 95% of them had a magnesium deficiency. The results of supplementation on ADHD symptoms have not been consistent but when given together with pyridoxine lower levels of hyperactivity, emotional over-reactivity and aggressiveness plus improved attention at school may result. Interestingly, a few weeks after stopping treatment, blood cell magnesium levels seem to go down and the symptoms of ADHD reappear [4].


It has been suggested that fibromyalgia (a chronic pain condition) and chronic fatigue syndrome are closely linked to magnesium depletion associated with dysfunction of the biological clock (circadian rhythms). The relationship between low magnesium and Mg deficiency has also been associated with disrupted sleep patterns.



Magnesium has been investigated in a range of conditions associated with acute or chronic pain. These include neuropathic pain, such as tumour-related neurologic symptoms, postherpetic neuralgia (e.g., after shingles), and neuropathy due to diabetes and chemotherapy. Other pain conditions that magnesium has been shown to be effective in include dysmenorrhea, tension headaches, and acute migraine attacks [5]

The understanding of how it works in pain is still evolving and clinical studies hope to clarify this.


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].


Magnesium status is highly associated with stress levels, with both stress and low levels of magnesium making stress worse and stress further depleting magnesium levels, creating a vicious circle. Low magnesium is also associated with stressful conditions such as light-sensitive headaches, fibromyalgia, chronic fatigue syndrome, stress induced by sound, cold, physical exertion. While it’s unknown how magnesium is involved, its role in neurotransmitter systems and neuro- hormones is the most likely and given that low magnesium may cause adrenaline to increase, this further accentuates the stress situation [5]. Need help with stress? Make an appointment

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Adult women typically need at least 300-350 mg per day, and men 400-420mg, though this varies according to health status and other factors. You typically absorb between 30% and 40% of the magnesium you consume.

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Food Sources of Magnesium

Food Sources of Magnesium mg
Almonds, dry roasted, 30g 86
Cashews, dry roasted, 30g 80
Spinach, boiled, ½ cup 78
Soymilk, plain or vanilla, 1 cup 61
Black beans, cooked, ½ cup 60
Oats, quick, raw, ½ cup 56
Edamame, shelled, cooked, ½ cup 50
Peanut butter, smooth, 2 Tblsp 49
Bread, whole wheat, 2 slices 46
Avocado, cubed, 1 cup 44
Potato, baked with skin, 100g 43
Rice, brown, cooked, ½ cup 42
Kidney beans, canned, ½ cup 35
Banana, 1 medium 32
Salmon, cooked, 100g 30
Milk, 1 cup 24–27
Raisins, ½ cup 23
Chicken breast, roasted, 100g 26
Beef, mince lean, cooked,100g 23
Yoghurt, plain, low fat, 100gs 21
Broccoli, chopped, steamed, ½ cup 12
Rice, white, cooked, ½ cup 10
Apple, 1 medium 9
Carrot, raw, 1 medium 7