How Does Magnesium Affect Cardiovascular Health and Longevity?

The short answer

Magnesium is an essential mineral involved in over 300 enzymatic reactions, including ATP synthesis, DNA repair, and muscle contraction. Deficiency is common in older adults (affecting 45–60%) due to reduced dietary intake, impaired absorption, and increased renal excretion. Each 0.2 mmol/L increase in serum magnesium is associated with a 22% lower cardiovascular mortality risk. Magnesium deficiency is associated with hypertension, cardiac arrhythmias, insulin resistance, and osteoporosis.

What the evidence actually shows

Del Gobbo et al. (2013) in BMC Medicine conducted a meta-analysis of 16 prospective studies and found that each 0.2 mmol/L increase in serum magnesium was associated with a 22% lower cardiovascular mortality risk and a 30% lower risk of fatal ischaemic heart disease. Rosanoff et al. (2012) in Nutrition Reviews found that 45–60% of Americans do not meet the estimated average requirement for magnesium. The primary dietary sources of magnesium are leafy green vegetables, nuts, seeds, legumes, and whole grains — all of which are under-consumed in Western diets.

"Each 0.2 mmol/L increase in serum magnesium was associated with a 22% lower cardiovascular mortality risk and a 30% lower risk of fatal ischaemic heart disease."

— Del Gobbo et al., BMC Medicine 2013

What the major health authorities say

MedlinePlus identifies magnesium as an essential mineral for heart health, muscle function, and bone health, noting that many Americans do not get adequate amounts. The NIA recommends adequate magnesium intake as part of a healthy diet for older adults. The recommended dietary allowance for magnesium is 420 mg/day for men and 320 mg/day for women over 50.

Practical implications

The best dietary sources of magnesium are: pumpkin seeds (156 mg per 28g), chia seeds (111 mg per 28g), almonds (80 mg per 28g), spinach (78 mg per 100g cooked), black beans (60 mg per 100g), and dark chocolate (64 mg per 28g). For those unable to meet requirements through diet, magnesium glycinate or magnesium citrate are better absorbed than magnesium oxide. Magnesium threonate has specific evidence for brain penetration and cognitive benefits. Serum magnesium testing is available but underestimates total body magnesium (most is intracellular); a normal serum level does not rule out deficiency.

Where reasonable people still disagree

• Whether magnesium supplementation reduces cardiovascular events in individuals with normal serum magnesium levels, or only in those with confirmed deficiency.
• The optimal form of magnesium for different health outcomes — glycinate for sleep and anxiety, threonate for cognitive function, citrate for general supplementation.
• Whether the cardiovascular benefits of higher magnesium intake are primarily attributable to magnesium itself or to the dietary patterns (Mediterranean, plant-rich) that are high in magnesium.