Low dietary magnesium may increase risk of fatal heart attack in women

USA: Higher dietary magnesium intake reduces the risk of fatal coronary heart disease (CHD) in women, suggests a recent study in the Journal of Women's Health. The study further found an increased risk of fatal CHD and sudden cardiac death (SCD) in postmenopausal women with a low intake of dietary magnesium.

Magnesium-rich foods include green leafy vegetables (e.g. spinach and kale), fruits (figs, avocado, banana, and raspberries), nuts and seeds, legumes (black beans, chickpeas, and kidney beans), vegetables (peas, broccoli, cabbage, green beans, artichokes, asparagus, brussels sprouts), seafood, and whole grains.

Postmenopausal women represent the highest population-based burden of cardiovascular disease, including sudden cardiac death (SCD). However, the understanding of the aetiology and risk factors contributing to fatal CHD and SCD is limited, particularly among women.

Magnesium is known to play an important part in cardiac electrophysiology. Both extracellular and intracellular magnesium have significant effects on cardiac ion channels. Therefore, magnesium, and in particular hypomagnesemia, is thought to play an important role in the pathophysiology of many cardiovascular diseases.

Charles B. Eaton, Alpert Medical School of Brown University, Pawtucket, Rhode Island, and colleagues examined the association between dietary magnesium intake and fatal CHD and SCD.

For the purpose, the researchers examined 153,569 postmenopausal women who participated in the Women's Health Initiative recruited between 1993 and 1998. Baseline intake of magnesium was assessed using a validated food frequency questionnaire, adjusting for energy via the residual method. Fatal CHD and SCD were identified over an average follow-up of 10.5 years.

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Key findings of the study include:

• For every standard deviation increase in magnesium intake, there was statistically significant risk reduction, after adjustment for confounders, of 7% for fatal CHD (hazard ratio [HR] 0.93), and 18% risk reduction for SCD (HR 0.82) the latter of which did not reach statistical significance.


• In age-adjusted quartile analysis, women with the lowest magnesium intake (189 mg/day) had the greatest risk for fatal CHD (HR 1.54) and SCD (HR 1.70).


• This association was attenuated in the fully adjusted model, with HRs of 1.19 for CHD and 1.24 for SCD for the lowest quartile of magnesium intake.

"This study provides evidence of a lower risk for women with higher dietary magnesium intakes for fatal CHD and potentially an increased risk between low dietary magnesium and fatal CHD and SCD in postmenopausal women. Future studies should confirm this association and consider dietary trials of foods rich in magnesium (e.g., fruits and vegetables) and magnesium supplementation in the general or at-risk populations," concluded the authors.

The study, "Association of Dietary Magnesium Intake with Fatal Coronary Heart Disease and Sudden Cardiac Death," is published in the Journal of Women's Health.

DOI: https://doi.org/10.1089/jwh.2019.7775