Magnesium is an essential mineral that plays many important roles in the body, including regulating blood pressure. However, there has been some debate around whether magnesium supplements may actually increase blood pressure in certain individuals. In this article, we’ll explore the current research on magnesium and high blood pressure and try to answer the question of whether magnesium can cause high blood pressure.
What is magnesium and what does it do in the body?
Magnesium is a mineral that is found naturally in many foods and is also available as a dietary supplement. It plays several critical roles in the body:
- It helps regulate muscle and nerve function
- It supports a healthy immune system
- It keeps bones strong
- It regulates blood glucose levels
- It aids in the production of energy and protein
One of magnesium’s main jobs is to help regulate blood pressure. It does this by dilating (widening) the blood vessels, which allows blood to flow more freely and decreases pressure. Studies have shown that people who consume diets higher in magnesium tend to have lower blood pressure than those who consume less magnesium.
Does magnesium lower or raise blood pressure?
Most research to date has shown that increasing magnesium intake tends to lower blood pressure, especially in those with high blood pressure or who are deficient in magnesium.
According to a meta-analysis of double-blind randomized controlled trials published in Hypertension, magnesium supplementation results in a modest reduction in blood pressure, particularly in people with hypertension. The analysis looked at data from 34 clinical trials including over 2,000 participants. On average, magnesium supplementation reduced systolic blood pressure by 2-3 mm Hg and diastolic blood pressure by 1-2 mm Hg.
Other research shows that among people with higher blood pressure, those with lower magnesium levels tend to experience a greater blood pressure reduction from magnesium supplementation.
Overall, the scientific evidence strongly indicates that getting adequate magnesium can help lower high blood pressure. The recommended daily allowance (RDA) for magnesium is 310-420 mg per day for adults. Many people do not get enough magnesium from food alone, so supplementation may help boost intake.
Can magnesium supplements raise blood pressure?
While most evidence shows that magnesium lowers blood pressure, some studies have found that magnesium supplements may raise blood pressure in certain situations.
According to a 2002 review published in American Journal of Clinical Nutrition, magnesium supplementation results in a slight increase in blood pressure among people with normal blood pressure who are not deficient in magnesium.
The authors propose a few potential reasons for this effect:
- In healthy people with no magnesium deficiency, excess magnesium may cause an imbalance with calcium, leading to vasoconstriction (narrowing of the blood vessels).
- Magnesium supplementation inhibits the renin-angiotensin-aldosterone system (RAAS), which regulates blood volume and arterial resistance. Inhibition of RAAS leads to increased retention of sodium and water, which can increase blood pressure.
- High-dose magnesium supplementation may directly promote vasoconstriction.
However, the increases seen in these studies were generally small, averaging around 2-3 mm Hg for systolic blood pressure in healthy people without high blood pressure.
Larger effects have been seen in some cases. For example, one study published in Hypertension found that magnesium infusion acutely increased blood pressure by 5-7 mm Hg in people with essential hypertension.
Overall, the balance of evidence suggests magnesium is more likely to lower blood pressure, but it may potentially increase blood pressure slightly in some normotensive individuals. More research is needed on the dose-response effects.
Who may be more likely to experience blood pressure increase?
Based on the current research, the people more likely to experience a slight blood pressure increasing effect from magnesium supplements include:
- Those with normal blood pressure
- People who are not deficient in magnesium
- People taking very high doses of magnesium
On the other hand, those with hypertension or who are deficient in magnesium appear more likely to experience a blood pressure lowering effect.
Some medical professionals advise caution with magnesium supplementation in people with normal blood pressure readings. Monitoring of blood pressure is recommended, especially when taking high doses.
However, any increases seen in studies are generally small and transient. For most people, potential benefits of magnesium supplementation likely outweigh hypothetical risks.
What magnesium dose is optimal?
When it comes to magnesium supplementation, more does not necessarily equal better. The recommended daily intake for adults is 310-420 mg per day.
There is some evidence that magnesium doses on the higher end of this range (350-420 mg/day) tend to have a greater blood pressure lowering effect. However, taking more than this does not appear to provide additional benefit and may come with greater risk of side effects or drug interactions.
It’s best to choose a moderate magnesium dose of around 350-400 mg/day, unless instructed to take higher or lower doses by a doctor. Make sure to pay attention to magnesium from both food and supplements when considering total intake.
Consuming magnesium from high-magnesium foods as part of a balanced diet is the optimal approach for most people. Food sources provide additional nutrients and fiber. Good food sources of magnesium include nuts, seeds, legumes, leafy greens, whole grains, and some fish and fortified foods.
Are there any risks or side effects?
Magnesium is generally very safe when consumed in moderate food-based doses. However, extremely high doses from supplements may cause side effects in some people.
Potential side effects of too much magnesium include:
- Diarrhea
- Nausea
- Abdominal cramping
- Lightheadedness
- Fatigue
High magnesium doses can also potentially interact with certain medications, including antibiotics and blood pressure medications.
People with kidney disorders should be cautious with magnesium supplements, as the kidneys aid in excreting excess magnesium.
Stick with moderate magnesium doses around the RDA to avoid potential risks and side effects. Unless directed by a doctor, avoid exceeding the Tolerable Upper Intake Level (UL) for magnesium of 350 mg per day.
Key takeaways on magnesium and blood pressure
In summary, the key points on magnesium and blood pressure include:
- Getting adequate magnesium from foods and supplements generally helps lower high blood pressure, especially in people who are deficient.
- In people with normal blood pressure who get adequate magnesium, supplements may potentially cause a slight short-term increase of around 2-3 mm Hg.
- Higher risk groups for blood pressure increases with magnesium include those with normal blood pressure taking very high doses.
- To optimize benefits while minimizing risks, aim for magnesium intakes of 310-420 mg per day, preferably from whole food sources.
- Work with your healthcare provider to determine if magnesium supplementation is appropriate for your individual health condition and needs.
Conclusion
Overall, magnesium is an important mineral that most people should strive to get adequate amounts of daily through diet and potentially supplements. It offers a variety of health benefits, with one of the most well-researched being reduction of high blood pressure.
For those with hypertension, increasing magnesium intake under medical supervision can be an effective addition to a blood pressure lowering regimen. Those with normal blood pressure readings should be cautious with high supplemental doses of magnesium but likely don’t need to avoid magnesium entirely.
As with any supplement, it’s ideal to focus on getting nutrients from whole food sources first whenever possible. Work with a healthcare professional to determine the optimal amount of magnesium for your individual health needs.