Does magnesium interfere with blood pressure medication

You may be wondering if you need to add magnesium supplements into your daily routine. Magnesium is a mineral our bodies use for the process of converting food into usable energy and many other biochemical reactions, from DNA synthesis to blood pressure regulation. 

Our bodies store magnesium in our bones, where the body accesses it through a cycle of bone mineralisation and demineralisation. It is important for us to replenish our body’s magnesium supply in order to keep ourselves healthy and keep our biochemical processes working smoothly. 

So, when might you need to invest in the best magnesium supplement? Here, we’ll look at the dietary routes you can take first, how the body uses magnesium, and how magnesium deficiency might affect the body. 

Why do we need magnesium?

According to Cristy Dean, registered dietician and owner of Fettle and Bloom (opens in new tab), magnesium is important for many processes in the body. “This includes regulating muscle and nerve function, blood sugar levels, blood pressure and making bone, protein and DNA,” she says. “Magnesium affects the hypothalamus which regulates stress hormones. If magnesium levels are optimal this can help manage stress and anxiety.”

A review in the Nutrients (opens in new tab) journal found that chronic stress and anxiety depletes the body’s stores of magnesium, which means the body is hit harder by stress. Our bodies end up in a cycle of magnesium depletion due to stress, then cannot handle the stress due to the reduced magnesium levels. This creates a poor stress response as a result, causing more stress in turn. Stress reduces our magnesium stores, and we need magnesium to deal with stress, so you can see how this can cause problems for those with chronic stress and anxiety. 

Another study in Magnesium Research (opens in new tab) journal found that magnesium supplementation can be helpful in the treatment of mild anxiety and anxiety related to premenstrual syndrome in women.

Magnesium also interacts with the sleep hormone melatonin and the neurotransmitter GABA, which are responsible for proper and restful sleep. A review in the journal of Biological Trace Element Research (opens in new tab) indicated that magnesium levels in the body might have a relationship with sleep duration, quality, daytime sleepiness and even snoring. 

Do magnesium supplements work?

The US Department of Agriculture (opens in new tab) estimates that 48% of Americans are not consuming enough magnesium and may need to supplement their diet.

Dean encourages trying to increase dietary magnesium before turning to supplements. “The best way to meet requirements is by eating a variety of foods such as legumes, nuts, seeds, wholegrains, fortified cereals and milk products. If you are worried about your magnesium levels or suspect you may be deficient, speak to a medical professional about supplementation,” she says. 

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Alcoholics are more likely to have low magnesium levels, as are those who have underlying gastrointestinal conditions such as Crohn’s disease or celiac disease. This is due to the unhealthy, damaged or diseased gut lining causing nutrient malabsorption. If someone has insulin resistance or type 2 diabetes, they may find themselves urinating more often due to high concentrations of glucose in the kidneys, which can mean that they end up passing higher levels of magnesium than the average person.

Dean also advises that those with health conditions related to malabsorption might want to consider supplementing their diet. “Some medical conditions and medications can interfere with the ability to absorb magnesium or increase the amount the body excretes,” she says. “Those with crohn's or celiac disease, type 2 diabetes, alcoholism and the elderly are more at risk of magnesium deficiency.” 

Another group who might want to consider supplementation under the guidance of a doctor is pregnant women. Pregnant women have slightly higher magnesium requirements than most people due to the extra magnesium needed to build and support the baby’s skeleton in-utero. A Chochrane (opens in new tab)review found that magnesium supplementation may significantly reduce the risk of hospitalization in pregnant women. It might also lower the risk of pre-eclampsia, although more research is needed in this area and there are other factors involved. 

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Are magnesium supplements safe?

It is advised that you do not exceed 400mg of magnesium a day or you may experience symptoms such as diarrhea, nausea and abdominal cramps. Magnesium toxicity can be fatal in rare circumstances, so always ensure you are taking no more than the recommended dosage. 

It is also important to note that magnesium supplements can interact with other medications, and some medications are already high in magnesium (some antacids and laxatives), so always check with your doctor before adding a supplement into your diet.

Dean warns that while dietary magnesium is unlikely to make you ill, a magnesium overdose is possible with supplements. “Magnesium that is naturally present in food is not harmful and does not have to be limited as our body has a way of getting rid of any excess via the kidneys,” she says. “However, supplementation can be harmful if taken in the wrong dose.” 

Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives. 

She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.