Low Vitamin B12, Homocysteine, and Atherosclerosis: Where the Mechanism Is Strongest

B12 is required for methionine synthase activity. When that pathway underperforms, homocysteine may accumulate and methylation balance can be disrupted.

This is why low B12 is often discussed alongside methylmalonic acid and homocysteine rather than with serum B12 alone.

Endothelial dysfunction is an early step in atherosclerosis. Experimental and review literature on hyperhomocysteinemia describes oxidative stress, nitric oxide disruption, inflammatory signaling, and direct endothelial injury as plausible contributors.

That makes endothelial damage from low vitamin B12 a defensible mechanistic phrase when it is framed through homocysteine biology rather than as a guaranteed clinical outcome.

Atherosclerosis is still shaped more strongly by smoking, LDL burden, diabetes, blood pressure, kidney disease, and inflammation than by a single vitamin marker alone.

That is why a mechanistic article should complement, not replace, the broader cardiovascular risk conversation.