Magnesium

Why magnesium is good for you

Every cell in the body needs magnesium to produce energy. Magnesium is required to make more than 300 different enzymes and to send messages along the nerves.

Magnesium makes the muscles relax and that ensures the heart is healthy and beats regularly, preventing abnormal heartbeat. Magnesium is also needed to keep blood pressure down to normal levels.

Magnesium is required so that the body can use other vitamins and minerals properly – vitamin C and calcium work better, for example, when there is sufficient magnesium in the body.

Magnesium works very closely with calcium to help keep bones strong throughout life.

There is about 25 grams of magnesium in the body and most of it is in the bones and teeth, but there is also a lot in the muscles and blood. The amount in the blood is very important as it ensures there is correct balance in various body processes. In the same way calcium is needed to make the muscles contract (when the heart beats) magnesium is needed to make the muscles relax again. The levels of magnesium and calcium in the blood need to be steady and sufficient. If there are insufficient blood levels of calcium and magnesium, the body will pull it from the bones and send it to the blood, which can result in weakened bones.

Important magnesium facts

Magnesium is starting to become more of a mainstream medication for people with the following health conditions:

• Arrhythmia – some people with arrhythmia may have a lack of magnesium, which is one reason why emergency departments use intravenous magnesium (or potassium) for people with certain heart arrhythmias and cardiac infarction
• Asthma – magnesium is used in emergency departments of hospitals for people with asthma to help their airways open up, by relaxing the smooth muscles surrounding the bronchi and reducing risk of dying from a severe asthmatic attack
• Migraines – people with migraines often find that their symptoms improve with magnesium supplementation as it relaxes the smooth muscles and reduces the symptoms associated with severe migraines

Talk to a medical professional about magnesium supplements before taking them

Magnesium works best with

• Vitamin B1
• Vitamin B6
• Vitamin C
• Vitamin D
• Boron
• Calcium
• Potassium
• Zinc

Magnesium and health

• Heart problems – low levels of magnesium seem to be related to some types of heart problems. Because magnesium helps the heart muscles to relax, a short supply may cause a spasm in one (or both) of the coronary arteries that supply blood to the heart. This spasm blocks blood flow and can cause a heart attack. Some doctors think a deficiency of magnesium is the cause of many sudden heart attacks, especially in people who don’t have a history of heart disease. In fact, intravenous magnesium is used in emergency rooms in the Australia, UK, USA and other countries as part of the treatment for heart attacks (usually with potassium and other conventional medications)
• Blood clots – magnesium also protects against heart attacks caused by blood clots. Magnesium helps keep the clots from forming by making platelets (tiny blood vessels that form clots) less “sticky”, and this makes them less likely to lump together into an artery-clogging clot
• Heart arrhythmia – too little magnesium can cause cardiac arrhythmia. These are irregular heartbeats – an extra heartbeat, a skipped heartbeat or just a fast heart beat for no apparent reason. If the problem is serious enough, the heartbeat doesn’t return to normal and sudden death occurs. Studies suggest that people with low levels of magnesium are more likely to die suddenly from heart rhythm problems
• Magnesium manages blood pressure – magnesium helps the muscles relax and if there is insufficient magnesium, the walls of the blood vessels tighten up, which raises blood pressure. Coincidentally, many people with high blood pressure don’t get enough calcium either. Pregnant women sometimes get dangerously high blood pressure, especially in the last few months of pregnancy (due to pre-eclampsia). Magnesium may help prevent this problem. Pregnant women are usually prescribed a multivitamin supplement that has magnesium in it – don’t take extra magnesium supplements unless a medical professional has recommended it
• Magnesium and asthma – asthma causes the muscles lining the airways in the lungs to contract and become too narrow, which results in trouble breathing. Magnesium helps the smooth muscles that line the trachea and bronchi to relax, so the airways open up and breathing becomes normal and easier. In emergency rooms, intravenous magnesium is used to treat severe asthma attacks. People with asthma may have a diet that is low in magnesium, so getting more through higher intake of magnesium-rich foods and/or supplements could help prevent attacks and reduce severity of breathing problems. DON’T try to treat an asthma attack on your own by taking magnesium supplements – it could be dangerous – always take asthma medicines prescribed and see your doctor about magnesium supplements
• Healthy bones – not only is calcium required for healthy bones, but so is magnesium. Magnesium helps to keep the calcium levels in balance and also makes sure that enough vitamin D is produced. Twice as much calcium as magnesium is required for good health and any supplements should also have this ratio
• Diabetes – high blood pressure is often a problem for people with diabetes and people with diabetes often have low magnesium levels. Some doctors think there is a connection and recommend magnesium supplements for diabetic patients. Magnesium may also help diabetics control their blood glucose levels better and help prevent diabetes complications later on, like eye problems and heart disease. There is also some evidence that older people who are at risk for diabetes can prevent it by taking extra magnesium. People with diabetes, or at risk for it, should aim to get as much magnesium as possible from their diet and also consider taking a supplement. Talk to a medical professional about magnesium supplements before taking them, especially if there are kidney problems because of diabetes
• Migraines – People who suffer with migraine headaches often have low magnesium levels. Migraine sufferers should consider magnesium supplementation to help reduce the number of attacks and the severity. One study showed that in about half the cases, intravenous magnesium stopped migraine headaches in their tracks. Unfortunately, once a migraine is in effect, just swallowing magnesium supplements doesn’t have the same effect and it is better to take magnesium supplements on a continuous basis for them to take effect in reducing severity and incidence of migraines
• Kidney stones – Magnesium supplements seem to keep calcium kidney stones from coming back. Studies show that about 100-300mg of magnesium a day is required and seems to work better if 10mg of vitamin B6 (pyridoxine) is taken with it. People with kidney stones should talk to a medical professional about magnesium supplements before taking them
• PMS – Studies show magnesium supplements relieve uncontrollable PMS and PMDD symptoms, such as breast tenderness, headaches and irritability. Studies show that women with severe PMS should try 300-500mg of magnesium per day for the two weeks leading up to menstruation. If severe cramps are a problem at menstruation, keep taking magnesium during that time too – it may help reduce menstrual cramping. Magnesium supplementation may help even more if it is combined with calcium and vitamin B6 (pyridoxine) for PMS and PMDD symptoms

People who wish to take a magnesium supplement should talk to a medical professional before taking it.

Groups at risk of magnesium deficiency

About 75% of the population do not get enough magnesium from their foods to meet the RDI, so they may be borderline deficient. Even so, very few people are really severely deficient in magnesium, as it would require intake of very low amounts of magnesium over a long time to have any major symptoms.

Magnesium deficiency occurs when there is less than 85mg intake of magnesium per day.

Deficiency of magnesium can occur if the following health problems are present:

• Alcoholics – most people who drink alcohol excessively have poor diets that are too low not just in magnesium but also in the other nutrients too
• Diabetics – people with diabetes may be excreting a lot of magnesium in their urine
• People with kidney disease – the kidneys may not be handling magnesium very well. Your doctor will prescribe medications that prevent magnesium deficiency. People with kidney disease should NOT take magnesium supplements
• People that have been vomiting or have severe diarrhoea – people with any condition that causes vomiting or severe diarrhoea (or both) will be eliminating most of their magnesium (and other vital nutrients)
• People taking diuretic drugs – diuretics cause urine to be excreted more than normal and this may lower magnesium levels. This can pose a real problem if non-prescription or herbal diuretics (“water pills”) are used, without informing a medical professional if other medications are being used at the same time, as this can cause adverse health effects

People in these groups at risk of deficiency should talk to a medical professional about magnesium supplements before taking them.

Symptoms of magnesium deficiency

If there is insufficient dietary magnesium, all the tissues in the body will become affected in some way, but mostly the following will be the most adversely affected:

• Heart
• Kidneys
• Nerves

Generally magnesium deficiency symptoms

• Irritability
• Loss of appetite
• Muscle weakness or tremors
• Nausea

Severe magnesium deficiency symptoms

• Can cause the heart to beat irregularly

Many doctors and nutritionists feel that breathing problems, such as asthma are caused in part by a magnesium deficiency.

Magnesium in food

Magnesium recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

* The tolerable upper limit for magnesium for infants aged 0-12 months has not yet been determined due to a lack of data about the adverse effects in this age group. The only source of magnesium intake should be from food (breast milk and/or baby formula).

* The tolerable upper limit for magnesium for adults, pregnant and lactating mothers is for any supplements that are taken beyond any magnesium which is obtained in the diet.

There is no upper limit for magnesium in the diet, only an upper limit of magnesium from supplements.

Acute magnesium toxicity

Acute toxicity from taking too much in magnesium supplements – over 15g can cause the following symptoms:

• Difficulty breathing *
• Extreme muscle weakness
• Extremely low blood pressure *
• Irregular heartbeat *
• Paralysis of the central nervous system *
• Severe nausea
• Sleepiness
• Vomiting *

* People who experience the highlighted symptoms should seek immediate emergency treatment.

Chronic magnesium toxicity

Chronic toxicity of magnesium from taking higher than the therapeutic dose of supplements for a long time can cause the following symptoms:

• Confusion
• Diarrhoea
• Dry mouth
• Flushing
• Low blood pressure
• Mood changes
• Muscle weakness
• Sleepiness and lethargy
• Thirst

People who experience any of the above toxicity symptoms should discontinue their magnesium supplements and see their doctor for advice.

Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of magnesium is highly unlikely to cause overdosage.

Precautions

Certain people should not take magnesium supplements at all:

• People who have had an ileostomy
• People with heart blockage (unless a pacemaker is in place)
• People with heart failure
• People with kidney failure
• People who have appendicitis

People that have had an ileostomy will not be able to absorb the magnesium properly, cause further intestinal blockages, which could cause seriously adverse health effects.

People with any type of heart blockage could experience a relaxing of the heart muscles and a slowing of the heart rate, causing inability of the heart to beat sufficiently.

People with kidney failure will not be able to eliminate the excess magnesium, cause high blood magnesium levels and cause further kidney damage.

People with appendicitis should not take any type of magnesium supplements as there may be an increased danger of perforation or rupture of the appendix due to the magnesium’s constipating or laxative effects.

Certain people should not take magnesium supplements without first consulting their doctor for advice:

• People who have chronic constipation, colitis or diarrhoea
• Women who are pregnant or breastfeeding

People with the above conditions should get advice from their medical doctor before starting supplements to ensure magnesium supplementation does not conflict adversely with their condition.

People with kidney failure or congestive heart failure should NOT take magnesium supplements or antacids containing magnesium

Interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with magnesium supplements:

• Antibiotics
  Some antibiotics may decrease magnesium blood levels and inactivate any magnesium supplements that are taken.
• Cellulose sodium phosphate
  Cellulose sodium phosphate (used for preventing the formation of calcium-containing kidney stones) may decrease the effect of the magnesium supplements and so should be taken at least 1 hour apart (longer is preferable).
• Diuretics
  Some diuretics may cause magnesium levels to be decreased, even when magnesium supplements are taken.
• Ketoconazole
  If magnesium supplements are taken together with the medication Ketoconazole (used to prevent and treat skin and fungal infections), the magnesium can reduce the absorption of the Ketoconazole, so should be taken at least 2 hours apart.
• Mecamylamine
  If magnesium supplements are taken together with the medication Mecamylamine (used to help people stop smoking, for autism and high blood pressure) then the magnesium may decrease the rate of that Mecamylamine is eliminated in the urine. People taking Mecamylamine should avoid taking magnesium supplements.
• Tetracycline
  If magnesium supplements are taken together with the medication Tetracycline (antibiotics) then the magnesium may decrease the absorption of the Tetracycline, basically inactivating it and this could cause a flare-up of the bacterial infection.

Magnesium has some adverse interactions with a number of medications and other vitamins

The following are the supplements that are more likely to cause a reaction with magnesium supplements:

• Vitamin D
  High levels of vitamin D taken at the same time as magnesium may cause the blood magnesium levels to increase too high, so lower levels of vitamin D are advised

Magnesium lab test interactions

Magnesium has the following effect on lab tests:

• Serum and urine pH levels
  Magnesium supplements may decrease the pH levels of serum and urine.
• Serum phosphate
  Magnesium supplements could also either increase or decrease serum phosphate levels.
• Stomach acid secretion
  Tests to determine stomach acid secretions will have incorrect results when magnesium is supplemented.

People who are taking magnesium supplements should let their doctor know and should also stop taking supplements about 3-4 days prior to having any type of lab tests.

Interactions with other substances

There are none reported.

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