My Iron Problem 🤔🤔
Hi and happy Friday!
I first took an iron test back in May 2024. After this came in low, I started taking an iron supplement. However, despite seemingly getting enough iron through my diet and taking supplements, I have had a hard time getting my level to stay inside the reference range.
Here are my 4 tests:
May 2024: 41,09 μg/dL
July 2024: 40,44 μg/dL
August 2024: 159,80 μg/dL
January 2026: 35.0 μg/dL
The reference range is 65 - 175 μg/dL
I had one test in August 2024 that was great. What I did back then was to take a supplement that contained iron + vitamin C only.
I then switched to a multivitamin that contained 14mg of iron, and I assumed this was enough. However, given my test result from January 2026, it seems this is not enough.
What is going on? These seem to be the most likely answers:
Insufficient absorbed iron from my vegetarian diet: Plant-based (non-heme) iron has low bioavailability (typically 5–12% absorption vs. 15–35% for meat). Even if total intake looks “enough” on paper, actual absorbed amount is often too low to maintain levels.
The 14 mg iron in my multivitamin is too low a dose for repletion/maintenance: 14 mg is roughly the RDA for non-vegetarian adults, but vegetarians often need 1.8× higher intake (~25–32 mg/day total from food + supplements) to compensate for poor absorption.
Lack of consistent high-dose vitamin C paired with iron intake: My good August 2024 result (159.80 μg/dL) occurred when taking iron + vitamin C together. Vitamin C can boost non-heme iron absorption 2–6×. The multivitamin has some vitamin C, but not concentrated with the iron dose, reducing absorption efficiency significantly.
Dietary inhibitors blocking absorption (common in vegetarian diets):
Phytates (in whole grains, legumes, nuts, seeds)
Polyphenols/tannins (tea, coffee, red wine, chocolate)
Calcium (dairy alternatives, fortified plant milks, supplements) If these are consumed close to meals/supplements, they can reduce iron uptake by 50–90%.
What does this latest result change?
Based on my latest low result of 35.0 μg/dL, I have gone back to taking the same dedicated iron + vitamin C supplement I took when I got the great result.
It simply seems that even though I get a good amount of iron through my diet, and even if I take a multivitamin with 14mg of iron, my body does not get enough.
I will retest in not too long to see if my iron has gone back up.
What’s next?
Next week or the week thereafter, I will show you my updated biological age result. I have some positive news :)
For any new readers: I am trying to live to (at least) 151. To get there, I follow 2 main principles:
Live a super-healthy life (based on what science deems positive for longevity)
Measure what’s going on in my body and tune any metrics that are off to become optimal
I also summarize interesting news and stories from the longevity space. And I share everything worth sharing with you.
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Have a good day,
Johan
Here is an overview of all the tests I have taken so far: