Does higher dietary magnesium intake reduce the risk of dementia?

The evidence from these searches does not directly test whether higher magnesium intake reduces dementia risk. The link is plausible, but the specific question remains unstudied in what was retrieved.

None of the studies in this block measured dementia as an outcome [none]. A 2025 prospective cohort of 111 older adults found that low blood magnesium (hypomagnesemia) after COVID-19 predicted cognitive impairment at six months, with a striking joint risk when combined with depression [5]. That is a prediction study in a post-infection population, not a general dementia-prevention trial. The same study reported that depression and low magnesium each independently predicted cognitive decline [5].

The rest of the retrieval shows that higher magnesium intake is consistently tied to lower inflammation. In a national sample of over 5000 U.S. adults, lower magnesium tracked with higher C-reactive protein, a marker of systemic inflammation [6]. In 657 women, higher intake correlated with lower CRP, E-selectin, and sICAM-1 [3], all inflammatory signals that can damage blood vessels and the brain over time. Magnesium also showed inverse associations with insulin resistance [1], metabolic syndrome components [2], and epilepsy risk in older Finnish men [4] — all conditions that share pathways with dementia.

What is missing. No study in this set compared people with high versus low magnesium intake and tracked dementia incidence over years. The retrieved evidence supports a plausible mechanism (less inflammation, better metabolic control, better blood flow), but mechanism is not proof. The burden of proof remains unmet for the specific claim that higher dietary magnesium prevents dementia.

My call: the evidence here does not answer whether higher magnesium intake reduces dementia risk. The connection is biologically plausible through inflammation and metabolic pathways, but no dementia-outcome study appears in this retrieval. Confidence is low for a protective claim — the mechanism is suggestive, the direct evidence is absent.