Can Magnesium Help With High Blood Pressure?

If you have high blood pressure, you may be put on various medications to help control it. You will certainly be advised to change your lifestyle by eating healthier and exercising more, among other changes.

One thing that is often mentioned is getting enough magnesium. Magnesium is a key mineral for regulating blood pressure¹, and it also helps regulate blood sugar and supports proper muscle and nerve function.

How does magnesium lower blood pressure?

Magnesium helps lower blood pressure² in several ways. Among other things, it helps:

• Relax blood vessels

• Act as a natural calcium channel blocker

• Increase nitric oxide levels

• Reduce endothelial dysfunction³, which is an imbalance between relaxing and contracting factors in blood vessels

Many older adults are at least slightly deficient in magnesium⁴. Since age is a risk factor for high blood pressure, magnesium deficiency is likely involved in worsening blood pressure issues as we get older.

How much magnesium do you need?

Studies on supplementing magnesium levels indicate that 300 mg/day is enough to impact blood pressure significantly. However, there are also indications that increasing magnesium above normal levels is not advisable.

The positive impact of magnesium supplementation is primarily because you are correcting a deficiency⁵. If you already have adequate magnesium levels, supplementing with magnesium is not helpful.

Talk to your doctor or your nutritionist before taking a magnesium supplement.

Can you overdose on magnesium?

Yes and no. Your body will naturally get rid of excess magnesium, but your body might not be able to keep up if you take a supplement. Excess magnesium can cause nausea, abdominal cramping, and diarrhea.

The maximum amount of supplemental magnesium our bodies can tolerate is 350 mg/day for adults⁶. You should, therefore, check with your doctor first before taking a supplement. This is especially true if you take antacids or laxatives for stomach issues. These medicines often contain magnesium, so adding a supplement on top can quickly put you into the overdose zone.

Consistently taking in too much magnesium can lead to magnesium toxicity⁷, which may have fatal complications such as hypotension, respiratory paralysis, and cardiac arrest. However, it is nearly impossible to overdose on magnesium from natural food sources.

You should also avoid magnesium supplements if you have chronic kidney disease, as this can affect magnesium excretion and cause it to build up in your body.

What foods contain magnesium?

Rather than taking a supplement, the best way to make sure you are getting enough magnesium is to increase your intake of certain foods. Talk with your nutritionist first if your magnesium levels are low.

Foods that contain magnesium include:

• Whole grains, including brown rice and whole wheat bread, among others

• Tap, mineral, and bottled water, although the amounts are variable

• Certain seeds like pumpkin and chia seeds are an excellent source

• Almonds, cashews, and other nuts

• Peanuts and peanut butter

• Soy milk

• Potato skins, so not peeling your potatoes is an easy way to add magnesium to your diet.

• Plain yogurt

• Beans, especially black and kidney beans

• Green vegetables such as spinach and broccoli

• Chicken and beef

• Apples

• Bananas

• Avocados

• Carrots

• Oatmeal

It’s an especially good idea to look for foods high in both magnesium and potassium, such as bananas.

Again, the best way to get enough magnesium is from food. The variety of magnesium-containing food is high enough to make it easy to reach the daily recommended dose unless you have food intake problems.

Who is at particular risk for magnesium deficiency?

Certain people are likely to be at risk for magnesium deficiency. For people in these groups, magnesium supplementation may be necessary:

1. Older adults, since there is a decrease in magnesium absorption as we age

2. People with chronic alcoholism

3. People with gastrointestinal diseases that reduce the intake of nutrients, such as Crohn’s disease, celiac disease, and regional enteritis

4. People with avoidant/restrictive food intake disorder, which is sometimes associated with autism 

5. People with type 2 diabetes

Alcoholism results in poor dietary intake, gastrointestinal problems, and renal dysfunction, among other issues that can decrease magnesium absorption or increase excretion. So, if you are struggling with alcoholism, it is recommended that you take magnesium supplements.

Avoidant/restrictive food intake disorder is when a person consumes only a few select foods, and it leads to several nutritional deficiencies, depending on the foods being avoided.

People with type 2 diabetes can develop high blood pressure and, if you have both high blood pressure and diabetes, you are more likely to need a magnesium supplement.

It is sometimes impossible for people in these groups to consume enough magnesium from eating the right foods, at which point a supplement is recommended. However, improving your diet is still better as a first approach than taking supplements.

What kind of magnesium supplement should you take?

There are eight main types of magnesium supplements. These are categorized according to what the magnesium is combined with, and these supplements can vary considerably.

Here are the eight common types of magnesium and their uses:

Magnesium glycinate

This is the most common source of magnesium as a dietary supplement. Magnesium glycinate⁸, in the form of magnesium glycinate salt, is commonly recommended to people with a deficiency they can’t fix with diet changes.

Like all supplements, it is possible to overdose on magnesium. If you can increase dietary magnesium, you should talk to your doctor about discontinuing the supplement.

Magnesium taurate

Many doctors consider magnesium taurate⁹ the best supplement for people with hypertension (high blood pressure). Studies in rats show that it can help lower high blood pressure and protect your heart.

One theory is that taurine, the protein the magnesium is combined with, may positively affect blood pressure¹⁰.

Magnesium citrate

Magnesium citrate is used as a laxative, and it works by adding water to your stool so it will leave the body more easily. It’s also used for cleansing before a colonoscopy.

Magnesium citrate is a medicine, not a dietary supplement. It can sometimes have a more lingering laxative effect, cause blood in the stool, or lead to difficulty in having bowel movements.

Magnesium chloride

Also not a dietary supplement, magnesium chloride is used to treat severe magnesium deficiency and is given as an infusion into the vein in a healthcare setting.

Your doctor will only recommend this drug if you really need it, as it is difficult to administer and more expensive than oral alternatives.

Magnesium lactate

Magnesium lactate is another oral magnesium supplement. You should not take it with high-fat foods, which can interfere with how it’s absorbed in your body.

Magnesium malate

Magnesium malate is sometimes prescribed to help improve chronic fatigue and fibromyalgia symptoms, but studies have shown little benefit¹¹. 

Magnesium sulfate

Like magnesium citrate, magnesium sulfate, commonly called Epsom salt, is used as a laxative and, when used as bath salts, to help relieve muscle pain. It is not recommended for people with diabetes or kidney disease.

If you have rectal bleeding after taking magnesium sulfate, you should call your doctor at once. 

Magnesium oxide

This is used as both a supplement and, in higher doses, a laxative for one-off uses, such as before surgery. Magnesium oxide is also used as an antacid to relieve heartburn, indigestion, and stomach upsets for short periods. Because of this, it’s crucial not to take more than your doctor recommends, as it can affect your digestive system.

Any of these dietary supplement forms of magnesium will help lower your blood pressure. Which one your doctor recommends may depend on other medications you are taking.

You can also be allergic to a specific type of magnesium. Many, but not all doctors, will first recommend magnesium taurate because it may have a stronger effect on blood pressure. Studies are still being done, but it is unlikely to cause problems unless you have issues with taurine.

Your doctor may also not specify which magnesium supplement you should take. In that case, you can take whichever supplement is convenient for you. You may find that some supplements upset your stomach, so feel free to switch to another.

Talk to your doctor if you want to switch from the one they specifically suggested. It is still better to get your magnesium from your diet as much as possible.

Can magnesium interact with medications?

Yes, magnesium can interact with some medications. You should take care if you are taking the following:

Antibiotics

If you are put on antibiotics, make sure to take them at least two hours before or four to six hours after your supplement. Magnesium can decrease the effectiveness of some antibiotics if they are in your stomach at the same time.

Levodopa/Carbidopa (Sinemet)

This is a medication used to treat symptoms of Parkinson’s disease. People taking this medication should not take magnesium oxide or other supplements.

Muscle relaxants

Magnesium can relax muscles, increasing the effects of the muscle relaxant and thus the risk of side effects.

Potassium-sparing diuretics

These are also sometimes prescribed for high blood pressure. They can increase the amount of magnesium retained in your body, and this can result in an overdose if you take a supplement.

Digoxin

This drug is used to strengthen the heart. Magnesium can decrease the absorption of digoxin.

Anticoagulants

Magnesium can slow blood clotting.

Sulfonylurea

This is a medication used to treat diabetes, and it can interfere with some forms of magnesium. If you are on sulfonylurea, talk to your doctor about what kind of magnesium you can take.

Gabapentin

Gabapentin is an anti-seizure drug. Do not take gabapentin less than two hours before or four to six hours after your supplement.

Ketamine

Ketamine is used to treat severe pain and depression, and magnesium can increase its side effects.

High-dose zinc supplements

These supplements can prevent magnesium absorption.

As you can see, some of these interactions are with medication your doctor might give you for your blood pressure. Therefore, it is vital to tell your doctor if you are taking (or planning to take) magnesium and what form you are taking it in.

Your doctor may recommend a specific type. With some of these medications, you simply have to take them at different times daily.

Who should not take a magnesium supplement?

You should not take magnesium if you have kidney problems, which are a common complication of diabetes. If your kidneys are weak, they may not be able to clear magnesium from your body, letting it build up to toxic levels.

Talk to your doctor first if you have diabetes or any condition treated with medications that interact with magnesium. You should not take a magnesium supplement for your blood pressure without checking first with your healthcare provider.

If you are already getting enough magnesium, you don’t need to take a supplement. Supplementing will have no added benefit and could result in you overdosing. While it is hard to test magnesium levels as much of it is held in our bones, a blood test can give you a sense of whether your magnesium levels are adequate. 

The lowdown

There is evidence that not getting enough magnesium can worsen your high blood pressure. However, magnesium supplementation is unnecessary and potentially dangerous if you are not deficient, and magnesium supplements can interact with some blood pressure medication.

Your best option is to eat a healthy diet that includes plenty of foods rich in magnesium. Note that supplementation may be necessary if you have certain health conditions.

Always talk to your doctor before starting with a magnesium supplement. Ask their advice on which of the several types you should take for your specific condition.