What IS it about Magnesium?

Products Containing Magnesium. Healthy Food Concept.Magnesium (Mg) plays a lot of important roles in the body – and magnesium deficiency is one of the leading nutrient deficiencies in adults, with an estimated 80 percent being deficient  – it is worth considering how much magnesium you consume daily to check whether you might benefit from eating foods that are rich in magnesium and if not, taking magnesium supplements.

What does Mg DO?

Magnesium plays an important role in over 300 enzymatic reactions within the body including the metabolism of food, synthesis of fatty acids and proteins, and the transmission of nerve impulses.

Magnesium is one of the seven essential macrominerals; these are minerals that need to be consumed in relatively large amounts – at least 100 milligrams per day.

The human body contains approximately 25 grams of magnesium. Over 50 percent of that magnesium is stored in your bones, and the rest is found in muscle, soft tissues, and bodily fluids.

The following health benefits have been associated with magnesium.

1) Bone health

Magnesium is important for bone formation and it helps calcium get into our bones.

2) Diabetes

Magnesium plays an important role in carbohydrate and glucose metabolism and has a beneficial effect on diabetes.

Studies have shown the better the Mg intake the lower the risk of diabetes. For every 100 milligrams per day increase in magnesium intake (up to a point), the risk of developing type 2 diabetes decreases by approximately 15%.

Most magnesium intake in these studies was from dietary sources, not supplements.

3) Heart health

Magnesium is necessary to maintain the health of muscles, including the heart, and for the transmission of electrical signals in the body. Mg has been associated with lower risk of fatty build up in the arteries also lower risk of high blood pressure

There are a lot of people taking calcium supplements in the belief that this will help to reduce osteoporosis without realising that they need to balance this with enough Mg. If the Mg and calcium balance is not correct this can  increase the risk of arterial calcification and cardiovascular disease, as well as kidney stones.

4) Premenstrual syndrome

Research suggests that people experiencing premenstrual syndrome can reduce the severity of symptoms like bloated feeling, insomnia, leg swelling, weight gain, and breast tenderness by ensuring adequate intake of magnesium. Magnesium combined with vitamin B6 appears to be more effective.

5) Relieving anxiety

These can include muscle spasms, poor digestion, anxiety, and trouble sleeping. Lots of us have these symptoms and they don’t necessarily mean we are all deficient in Mg but it is something that is rarely considered as possibly part of the problem or even tested.

Magnesium is involved in over 300 biochemical functions in the body, such as regulating heartbeat rhythms and helping neurotransmitter functions.

A deficiency in Mg has also been linked to the following symptoms. Recurrent bacterial or fungal infections, tooth decay, muscle weakness and cramps, impotence, hypertension and cardiovascular disease,  kidney and liver damage, migraines, multiple sclerosis, glaucoma.

Alzheimer’s disease, restless leg syndrome, worsened symptoms of pre menstrual tension, behavioural disorders and mood swings have also been linked to us having less Mg in our bodies than we should.



The Recommended Daily Allowance (RDA) for magnesium depends on age and whether you are male or female. The National Institute of Health recommends end that children 1-3 years of age get 80 milligrams of magnesium a day, rising to 130 milligrams for children aged 4-8, and 240 milligrams for children aged 9-13.


After the age of 14, RDAs diverge for men and women, with men typically requiring more Mg than women due to a larger average body mass. At the age of 14-18, the RDA for males is 410 milligrams, and 360 milligrams for females.

Adult females are advised to get 310-320 milligrams per day. An RDA of 350-400 milligrams is advised during pregnancy, and 310-360 milligrams when breastfeeding.


The RDA of magnesium for adult males is 400-420 milligrams.




Like everything, this is multifactorial. Reduced amounts in soil that lowers the amount of magnesium present in crops; digestive disorders that lead to malabsorption of magnesium and other minerals in the gut; high rates of some medication and in particular antibiotics use that  adversely affects your digestive tract to the point that magnesium cannot be absorbed and properly utilized from foods.


The body also loses stores of magnesium every day from normal functions such as muscle movement, heartbeat and production of hormones. Although we only need small amounts of magnesium relative to other nutrients, we must regularly replenish our stores either from foods or magnesium supplements in order to prevent deficiency symptoms.


The kidneys primarily control levels of magnesium within the body and excrete Mg into the urine each day, which is one reason why urinary excretion is reduced when magnesium and other electrolyte statuses are low.


The amount of Mg that can be absorbed and retained in the body for use by the tissues is called the “bioavailability”. Mg has a medium level bioavailability. It is predominantly absorbed by the small intestine. The small intestine becomes less efficient at absorbing Mg if the surface cells are not as healthy as they should be. Unabsorbed magnesium is excreted in the faeces.




Nuts and seeds, dark green vegetables, whole grains, and legumes. Magnesium is also added to some breakfast cereals and other fortified foods.

Sunflower seeds, dry roasted, 1/4 cup: 128 milligrams

Almonds, dry-roasted, 1/4 cup: 105 milligrams

Sesame seeds, roasted whole, 1 ounce: 101 milligrams

Spinach, boiled, 1 cup: 78 milligrams

Cashews, dry-roasted, 1 ounce: 74 milligrams

Shredded wheat cereal, two large biscuits: 61 milligrams

Soymilk, plain, 1 cup: 61 milligrams

Black beans, cooked, 1/2 cup: 60 milligrams

Oatmeal, cooked, 1 cup: 58 milligrams

Broccoli, cooked, 1 cup: 51 milligrams

Peanut butter, smooth, 2 tablespoons: 49 milligrams

Shrimp, raw, 4 ounces: 48 milligrams

Black-eyed peas, cooked, 1/2 cup: 46 milligrams

Brown rice, cooked, 1/2 cup: 42 milligrams

Kidney beans, canned, 1/2 cup: 35 milligrams

Cow’s milk, whole, 1 cup: 33 milligrams

Banana, one medium: 33 milligrams

Bread, whole-wheat, one slice: 23 milligrams

Magnesium is lost during the refinement process of wheat, so it is best to opt for cereals and bread products made with whole grains. Most common fruits, meat, and fish, are low in magnesium.




Magnesium is connected to other nutrients within the body, including calcium, Vitamin K and vitamin D.


Experts believe that one of the reasons magnesium supplements are so beneficial is because they help counterbalance high levels of calcium that can accumulate in the body when people take calcium supplements regularly. Similarly, taking vitamin D  in high levels, or being deficient in vitamin K2, can lower magnesium stores in the body and contribute to a deficiency.


You need to be careful when using any supplement, including magnesium supplements. Consuming any supplement in doses that are too high can create an imbalance in other nutrients and toxicity.


Therefore it is always better to try to get your Mg or other nutrients from food sources, as foods naturally contain other important balancing nutrients.




Large doses of magnesium can cause a loss of central nervous system control. People with renal (kidney) insufficiency should not take Mg supplements unless advised to do so by their physician.

No cases of magnesium toxicity from food intake have ever been reported, and such an occurrence seems highly unlikely to arise in any normal diet. However, if you are considering taking a supplement, there are certain drug interactions that people should be aware of.

So always discuss magnesium supplements with your doctor before taking them.