Magnesium Supplements Lower A High Blood Pressure

Magnesium is one of the best supplements for lowering a high blood pressure. I’ve taken magnesium supplements for several years, ever since convincing trials suggested that people with the highest intakes tend to live the longest. One of the many ways in which magnesium works is by relaxing smooth muscle in blood vessel linings, to lower blood pressure, reduce arterial spasm and protect against heart attack and stroke.

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Magnesium lowers blood pressure

Researchers assessed the effects of magnesium on blood pressure in 34 trials, involving over 2000 people who took an average dose of 368mg magnesium per day for between 3 weeks and 6 months. Only 16 of the 34 trials involved people with confirmed hypertension, however. The other 18 studies involved people with a normal blood pressure. Overall, taking magnesium supplements reduced blood pressure by an average of 2/1.78 mmHg compared with placebo.

Even though this result is statistically significant, it is misleading, as it is skewed by the fact that magnesium supplements do not have any significant effect on blood pressure in people who do not have either hypertension or diabetes. The fact that taking magnesium does not lower a normal blood pressure is reassuring, as it means you can obtain all its other health benefits without fainting if your blood pressure is naturally in the optimum range.

When only the results from people taking medication to treat hypertension or diabetes were analysed, however, taking magnesium supplements in addition to their treatment lowered their blood pressure by 5.69/2.55 mmHg. A clear association was also found between increasing blood levels of magnesium and the degree of blood pressure reduction which helps to confirm a dose response.

Do you need a magnesium supplement?

Magnesium intakes are often low, with average intakes for men and women not meeting the recommended intake in the UK or the US. Most people would benefit from eating more magnesium-rich foods – dark chocolate coated Brazil nuts are an excellent and tasty source.

If you have high blood pressure (or simply hope to live longer) then a magnesium supplement won’t go amiss. Doses of up to 400mg per day are safe for long-term use as supplements.

If you are sensitive to their laxative effect (which is usually seen at higher doses although some are more susceptible than others), then you can rub in a magnesium oil, or add Dead Sea or Epsom salts to your bath to absorb magnesium through your skin. Do this at night, as a magnesium salt bath is extremely relaxing and will promote a deep night’s sleep.

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Click here to find out which foods provide magnesium.

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Image credits: gadini/pixabay; baibaz /shutterstock

About Dr Sarah Brewer

QUORA EXPERT - TOP WRITER 2018 Dr Sarah Brewer MSc (Nutr Med), MA (Cantab), MB, BChir, RNutr, MBANT, CNHC Cert IoD qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. After working in general practice, she gained a master's degree in nutritional medicine from the University of Surrey. Sarah is a registered Medical Doctor, a registered Nutritionist and a registered Nutritional Therapist. She is an award winning author of over 70 popular self-help books and a columnist for Prima magazine.

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2 thoughts on “Magnesium Supplements Lower A High Blood Pressure

  • Jill Ingledow

    Dear Dr Sarah,
    Thanks for your article on vitamin D supplementation. Would you be able to comment as well about vit D3 supplementation with vit K2 and magnesium?

    My vit D issue, recently 25nmols/l (like ‘running on fumes’??), is caused by taking ursodeoxycholic acid for Primary Biliary Cholangitis. The proportion of Urso in my bile acids has gone from 5% to probably 40-50% and totally changed the hydrophilic/hydrophobic balance – leading to abysmal absorption of fat-soluble vitamins A, D, E & K. Stopping the Urso is not possible as liver failure lies that way. Osteoporosis is also known issue with PBC and you should get a DEXA scan at diagnosis.

    So I’m now supplementing with vit K2-MK-7 and magnesium glycinate – apparently more easily absorbed – as they appear to be needed together for bone metabolism and it may also re-balance calcium that could be affecting my circulation and blood pressure that is a bit high. My calcium levels are fine.

    I hope you’ll find the issue of co-supplementation for improved vit D absorption interesting and write on it soon.

    thank you, Jill Ingledow

    • DrSarahBrewer

      Hi Jill, Vitamin K2 is important for telling calcium where to go and to prevent excess accumulating in the wrong place such as the arteries. Ursodeoxycholic acid interacts with some medicines, but has been found to improve vitamin D bioavailability There is a twist in that vitamin D levels also seem to affect disease severity and response to urso in PBC with higher vitamin D levels associated with less severe symptoms. Vitamin D can be given by injection so its worth asking your doctors about this if your absorption is poor. I hope that helps – this is a highly specialised area that I am not that familiar with. Best wishes, Sarah B