Magnesium is one of the best natural remedies for high blood pressure. Magnesium is a mineral found in many foods including include nuts and seeds (especially pumpkin seeds, Brazil nuts, almonds and cashews), dark green, leafy vegetables (especially spinach and Swiss chard), beans (especially soy, lentils and white beans), fish (especially mackerel), dried fruit (especially figs) and wholegrains (especially quinoa, millet, Bulgur wheat and brown rice).
Dark chocolate, cocoa and tap water in hard-water areas are also important sources for some people and, by helping to prevent a high blood pressure, may even account for some of the regional variation in the incidence of heart attack and stroke.
How magnesium lowers a high blood pressure
Magnesium is needed for over 300 enzymes to work properly in the body, making it essential for every metabolic process from the production of energy to the synthesis of protein and genetic material. It is needed for muscle contraction, nerve conduction, and to maintain your heart rhythm and blood pressure. You even need magnesium for the action of sex hormones, and for the production of brain chemicals to maintain normal mood and quality sleep.
Magnesium relaxes smooth muscle cells in artery linings to reduce blood pressure. The results from 7 studies, involving 135 people with resistant high blood pressure, whose systolic blood pressure (upper figures) remained above 155 mg despite prescribed antihypertensive treatment, showed that adding magnesium reduced their blood pressure by an average of 18.7/10.9 mmHg – an astonishing result.
Even studies that involved people with normal blood pressure and well controlled high blood pressure show that adding magnesium supplements at an average dose of 368mg per day, for 3 months, can produce small but significant reductions in blood pressure of 2.00/1.78 mmHg compared with placebo. This suggests that everyone can gain some benefit from taking magnesium supplements, even if their blood pressure is normal.
Magnesium protects against heart attack and stroke
More importantly, magnesium reduces arterial spasm, which is one of the underlying causes of a heart attack. This may explain why data from 19 studies involving almost 533,000 people show that the risk of cardiovascular events (heart attack, stroke) was 15% lower in those with the highest dietary magnesium intake and 33% lower in those with the highest blood levels of magnesium. Other large-scale studies suggest that every 100mg increase in dietary magnesium can reduce the risk of cardiovascular mortality by 25% for women.
Magnesium infusions are even used in hospital to treat high blood pressure in some situations, such as pregnancy.
Low magnesium intake is common
Lack of magnesium is common and may contribute to insomnia, fatigue, weakness, muscle trembling or cramps, numbness and tingling, loss of appetite, poor co-ordination, palpitations, hyperactivity, low blood sugar – and a raised blood pressure.
Unfortunately, processing strips out much of the magnesium from food sources such as grains. Average adult intakes in Europe and the US are therefore relatively low at around 323 mg for males and 228mg for females.
Low magnesium levels can cause spasm of coronary arteries (linked with angina or heart attack) and potentially dangerous abnormal heart rhythms. These effects seem to be more pronounced during times of stress. Among obese individuals with type 2 diabetes, heart rhythm abnormalities were twice as common in those with low magnesium levels.
Magnesium supplements can have a laxative effect
Magnesium sulphate is the main component of Epsom salts, which has been a popular laxative since Victorian times. Magnesium in high doses is also used medically to clear the bowel before procedures such as colonoscopy and surgery.
The average magnesium intake from food is around 280mg per day. Drinking water can also contain high levels of magnesium in some areas, and the maximum intake from food, plus supplements, plus water has been estimated at 1400mg per day. To put this into context, the dose prescribed medically to clear the bowel (in a preparation called Picolax) includes 3.5grams magnesium oxide (which is more than double the maximum estimated intake, and almost ten times higher than the EU RDA of 375mg.
Some people do seem to be more sensitive to the laxative effects of magnesium than others, which may depend on their other dietary intake of magnesium. Most people do not develop symptoms at a dose of 250mg per day, which is the suggested EU tolerable upper intake level from supplements. Some will develop symptoms at a dose of 400mg per day.
If you experience a laxative effect with magnesium supplements, cut back on the dose, take it every other day, or try a chelated form which has a more gentle effect.
You can also obtain magnesium by absorption through the skin by soaking in a bath containing magnesium salt flakes – which is fabulously relaxing before going to bed and will promote a good night’s sleep – or by using a magnesium-rich oil that is rubbed onto the skin (avoid cuts or it will sting).
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