Patrick Kee, MD, PhD, a cardiologist with Vital Heart & Vein, who was not involved in the review, explained to Medical News Today what a magnesium deficiency is, and how doctors can diagnose it.

He told us that:

“Magnesium deficiency can manifest in two distinct states: hypomagnesemia and chronic latent magnesium deficiency. Hypomagnesemia is relatively straightforward to diagnose, as it is characterized by a low serum magnesium level below 1.5 to 1.8 mg/dL [milligrams per deciliter]. However, total body magnesium deficiency without hypomagnesemia can be challenging to detect. This condition, known as chronic latent magnesium deficiency, can only be diagnosed through a magnesium tolerance test, which involves administering an intravenous infusion of magnesium followed by urine collections. Unfortunately, this test is laborious and not widely accessible.”

The review notes that people with chronic latent magnesium deficiency have reduced magnesium overall. However, their serum total magnesium still reads as normal.

This review notes several key points in the history of research regarding magnesium. For a while, the understanding was that magnesium deficiency was not a major issue and that if it was, it was mainly for people with conditions that impacted their body’s ability to absorb or excrete magnesium.

Research in the late 1990s and early 2000s began to support the idea that inadequate dietary magnesium led to not enough magnesium in the body. The results also suggested that this deficiency might affect cardiovascular function.

The review then notes that after 2006, many epidemiological studies, randomized controlled trials, and meta-analyses showed a relationship between magnesium and conditions like high blood pressure, heart failure, and cardiac mortality.

More recent data have added to these findings. Many studies from 2018 and on have found that magnesium status is inversely correlated with high blood pressure, stroke, coronary and ischemic heart disease, atrial fibrillation, heart failure, and cardiac morbidity and mortality.

The review then discusses how magnesium deficiency may contribute to cardiovascular problems. There may be multiple mechanisms involved.

For example, magnesium deficiency may contribute to inflammatory stress and oxidative stress. The author defines oxidative stress as “an imbalance between oxidants (reactive oxygen and nitrogen species) and antioxidants.”

Some data also supports the idea that magnesium deficiency may contribute to abnormal lipid levels and trouble with lipid metabolism.

For example, the author notes some data from human studies supports that chronic latent magnesium deficiency could lead to lipid changes. The review suggests that magnesium deficiency may also contribute to endothelial dysfunction and changes in electrolyte metabolism.

After discussion of the relationship between magnesium and cardiovascular disease, the review goes on to discuss magnesium intake. The author notes that it has been challenging to set how much magnesium people should consume.

A number of factors could impact how much magnesium someone needs. For example, some data support the notion that individuals who weigh more might need to consume more magnesium.

The review further notes that surveys indicate that many people are not consuming enough magnesium.

The author stresses that over one quarter of adults could have a magnesium intake that could lead to mild to moderate magnesium deficiency or chronic latent magnesium deficiency.

Despite the amount of research discussed in this review, it also has limitations.

This review is from one author and discusses data from multiple studies and findings from animal and in vitro research.

It is important to note that all the cited studies have their own limitations, even though they show direction. For example, a number of the discussed studies focused on postmenopausal women, so the results might not be applicable to other groups.

New research will need to be considered as it becomes available and can confirm or refute the evidence cited in this review. Overall, more research may be required, particularly to confirm the potential benefits of magnesium supplementation.

Cheng-Han Chen, MD, a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, who was not involved in the review, noted the following words of caution:

“Trials investigating the use of magnesium supplementation have not yet found a consistent benefit to heart health. If dietary magnesium deficiency is eventually confirmed to be a risk factor for cardiovascular disease, then magnesium supplementation may represent a potential avenue to improve cardiovascular outcomes. Prospective randomized controlled trials will be necessary to evaluate any potential therapeutic benefit from magnesium supplementation.”

Similarly, Kee told us that “the efficacy of magnesium supplementation in reducing hard clinical outcomes such as heart attack, stroke, and peripheral artery disease remains uncertain, particularly in individuals susceptible to magnesium deficiency, as previously mentioned.”

”The relative low cost and generic nature of magnesium supplementation may not provide sufficient motivation for extensive clinical trials to validate its potential in reducing cardiovascular outcomes. [Nevertheless,] oral magnesium supplementation appears to be safe, and individuals have the autonomy to decide whether to incorporate it into their regimen,” he added.

However, it is important to note that the review notes some of the potential benefits of magnesium supplementation. For example, one umbrella meta-analysis of randomized controlled trials cited in the review suggested that magnesium supplementation helps to decrease blood pressure.