Overview
- A peer‑reviewed study published in late May 2026 measured plasma homocysteine, folate and vitamin B12 in about 600 healthy Japanese adults and found higher homocysteine was tied to lower B12 and folate levels.
- When men and women were analysed separately, higher homocysteine was linked with more physical fatigue in men and with reduced motivation in women.
- Researchers used validated self‑report tools for fatigue and motivation and adjusted for age, sleep, workload and diet, but the data are cross‑sectional so they show association not cause.
- Lead author Professor Hiroaki Kanouchi advised avoiding B12 and folate deficiencies through a balanced diet, and no clinical guidelines or policy changes have followed the report.
- Homocysteine is already monitored for heart, brain and bone risks, and if these findings are replicated they could broaden how clinicians and patients consider nutrition when unexplained fatigue or low motivation occur.