Vitamin B12 & Folate
Table of contents
Vitamin B12 is the one result in my October blood test that was flagged for being slightly too high. It sounds alarming but almost certainly isn’t. This article covers what B12 and folate do, why mine went up, and why I’m not worried.
Snapshot
| Marker | April 2026 | October 2026 | Normal range | Status |
|---|---|---|---|---|
| Vitamin B12 | 293 pmol/L | 590 pmol/L | 145–569 | ⚠️ slightly above range, harmless |
| Folate | 15.1 nmol/L | 30.9 nmol/L | 10.2–73.0 | ✅ normal, doubled |
Here’s the October result from my report. The “15.1 →” is my doctor noting April’s folate:
What they are
Vitamin B12 and folate (vitamin B9) are B vitamins that work as a team:
- Making red blood cells. Without enough of either, red cells come out large and don’t work properly (megaloblastic anaemia).
- Nerves. B12 helps keep the protective coating around nerves healthy. That’s why doctors sometimes prescribe it for nerve problems.
- DNA and cell division. Both are needed whenever the body makes new cells.
- Clearing homocysteine. B12 and folate break down homocysteine, an amino acid linked to heart risk when it’s high (more in the homocysteine article).
B12 comes mostly from animal foods (meat, fish, eggs, dairy). Folate comes from leafy greens, beans and fortified foods.
What I’m aiming for
To be inside the normal range for both: B12 145–569 pmol/L, folate 10.2–73.0 nmol/L. There’s no extra benefit to being above range. You just pass the extra out in your urine.
April: fine, but low-ish
April was already fine for both, so there was no problem to fix. Folate at 15.1 was nearer the bottom of its range than the top, and homocysteine was 14.36, close to its limit of 15. That combination is one reason it’s good to see folate higher now.
Why October went up
B12 590 (slightly above range). The most likely reason: in early October I was diagnosed with a disc problem in my neck that was irritating a nerve, and as part of the treatment I was prescribed mecobalamin, a form of B12 commonly given to support nerve recovery. Taking B12 tablets daily in the weeks before the test would easily push the level just above range. My extra protein, meaning more meat and eggs, probably added a bit too.
Why I’m not worried: B12 is water-soluble, the body excretes what it doesn’t need, and a level just above range from a supplement is generally considered harmless. A high B12 without a supplement to explain it would be worth looking into, but that’s not my situation. It should settle back into range once I’m off the prescription.
Folate 15.1 → 30.9 (doubled). I didn’t take a folate supplement, so this is probably diet: more protein foods, lower-GI carbs like brown rice, and generally eating more deliberately around training.
Both going up probably also helped another result: homocysteine dropped from 14.36 to 9.78.
What’s next
- Recheck B12 next time. I expect it back in range once I’ve finished the prescribed B12. If it stays high without a supplement, I’ll ask about it.
- No action needed on folate. It’s comfortably in range.
This is my own personal data, shared for interest only. It’s not medical advice.
Until next time, peace and love!