Zinc
Table of contents
Zinc was one of the two deficiencies in my April blood test, along with vitamin D. Six months of a daily zinc supplement fixed it, maybe a bit too well. This article covers what zinc does, why April’s level was a concern, and why the dose I’m taking is the next thing to look at.
Snapshot
| April 2026 | October 2026 | Normal range | Status | |
|---|---|---|---|---|
| Zinc (serum) | 8.64 µmol/L | 18.41 µmol/L | 11.07–19.03 | ✅ normal, near the top |
Here’s the October result from my report. The handwritten “8.64 →” is my doctor noting the April value:
What it is
Zinc is a trace mineral. The body only needs a little, but it’s involved in a lot:
- Immune function: it’s needed for white blood cells to work properly.
- Healing and repair: wound healing and tissue repair, which matter when you’re getting banged up on the mats.
- Hormones and enzymes: it’s part of hundreds of enzymes and is involved in testosterone production.
- Taste and appetite: low zinc can dull your sense of taste.
The body doesn’t store much zinc, so it needs a steady supply from food. Meat, shellfish (oysters especially), eggs, dairy, nuts and seeds are good sources.
The test here is serum zinc, the level in the blood. It’s a rough measure, since it can dip with recent meals, the time of day and inflammation, but a level as low as mine in April was hard to ignore.
What I’m aiming for
Simply to be inside the normal range (11.07–19.03 µmol/L), ideally in the middle rather than at either edge. More isn’t better with zinc, as you’ll see below.
Why April was a problem
At 8.64 µmol/L I was well below the bottom of the range: a clear deficiency, not a borderline one.
Why would a fit person be low? Zinc is lost in sweat, and I sweat a lot training in Singapore’s heat. Weight-cutting and tighter eating can also cut back on zinc-rich foods. That’s probably what tipped me under.
The risks of staying low:
- More infections and slower healing. Not great when grappling means minor skin injuries and close contact with training partners.
- Lower testosterone over time, and poorer recovery.
- Reduced appetite and taste, which makes it harder to eat enough when training hard.
Why October is better
From April, I took 50 mg of zinc a day. October’s 18.41 µmol/L shows the supplement did its job: up almost 10 points, from clearly deficient to the top end of normal. More protein in my diet (more meat and eggs) probably helped a little too.
What’s next: the dose
This is the part I want to be honest about. 50 mg a day is a high dose. The usual safe upper limit for adults is about 40 mg a day from all sources combined, and I’ve been above that for six months, on top of the zinc in my food.
Why it matters: high zinc over a long period can lower copper. Zinc and copper compete to be absorbed in the gut, so too much zinc can slowly lead to copper deficiency. That can in turn cause anaemia and low white cells, which is a little uncomfortable given that my red cell count is still slightly low and my white cells are at the bottom of their range (see Haemoglobin & Red Cells). Copper wasn’t tested in either of my blood panels, so I don’t know where it is.
So this is something I’ll ask my doctor about:
- The dose: whether to drop to a lower maintenance dose, or stop for a while, now that I’m near the top of the range.
- A copper test: checking copper (and ideally ceruloplasmin, the protein that carries it) at my next blood test, to make sure the zinc hasn’t pushed it down.
This is my own personal data, shared for interest only. It’s not medical advice.
Until next time, peace and love!