Hi,
I dose 3 times per day, 6am (Levo & T3) and 2pm and 10pm. Would it be ok to take 2mg of iron as part of a B-complex?
I purchased the wrong product a while ago and I don't want to waste money and throw it away.
Reading PR's book it states; take thyroid hormone meds 1 hr before iron sups, or take thyroid meds 4hrs after iron sups..
Many thanks and advice,
Kr,
Joe
That doesn't sound right to me. As far as I know it should be 4 hours away from thyroid hormone, meaning four hours before AND four hours after. But as you take your thyroid hormone every 8 hours, you could slip the iron in at 6 pm. Best in between two doses of T3 because T3 is less likely to be affected if you take the iron a bit late one day. And, of course, you could always take the following dose of T3 a bit later to make up for it.
2 mgs? That doesn’t sound right either…
Regards to timing - Thyroid hormones should be 4 hours after, but some may argue 3 is enough. If its 2 hours before Levo time, I’ll skip that days iron and double up the next day.
And since the blocking happens in the digestive tract, as long as you take Levo and wait long enough for it to get to your small intestines , you’re ok to take iron at that point. greygoose - I think that’s 1 hour? But in practice I would always wait a solid 2 for good measure.
After doing a lot of research in iron metabolism, personally I do try to leave 3-4 hours on either side. But it does get tough with multi day Levo dosing.
edit- and with your every-8-hour thyroid hormone dosing you’ve got a perfect 10 am and 6 pm slot for any supplements, right?
When Iron was found to interfere, the surprise was how big a time gap is required. Either the levothyroxine can "catch up" with the iron, or the iron with the levothyroxine, which is why such a long gap is required.
Below is one of the earliest reports from 1992. And later papers went further in determining the time needed.
Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism.
Campbell NR 1 , Hasinoff BB , Stalts H , Rao B , Wong NC
Annals of Internal Medicine, 01 Dec 1992, 117(12):1010-1013
doi.org/10.7326/0003-4819-1... PMID: 1443969
Abstract
Objective
To determine whether simultaneous ingestion of ferrous sulfate and thyroxine reduces the efficacy of thyroid hormone in patients with primary hypothyroidism.
Design
Uncontrolled clinical trial.
Setting
Outpatient research clinic of a tertiary care center.
Patients
Fourteen patients with established primary hypothyroidism on stable thyroxine replacement.
Intervention
All patients were instructed to ingest simultaneously, a 300-mg ferrous sulfate tablet and their usual thyroxine dose every day for 12 weeks.
Results
After 12 weeks of ferrous sulfate ingestion with thyroxine, the mean level of serum thyrotropin (thyroid stimulating hormone, TSH) rose from 1.6 +/- 0.4 to 5.4 +/- 2.8 mU/L (P < 0.01), but the free thyroxine index did not change significantly. Subjective evaluation using a clinical score showed that nine patients had an increase in symptoms and signs of hypothyroidism; the mean score for the 14 patients changed from 0 to 1.3 +/- 0.4 (P = 0.011). When iron and thyroxine were mixed together in vitro, a poorly soluble purple complex appeared that indicated the binding of iron to thyroxine.
Conclusions
Simultaneous ingestion of ferrous sulfate and thyroxine causes a variable reduction in thyroxine efficacy that is clinically significant in some patients. The interaction is probably caused by the binding of iron to thyroxine.
europepmc.org/article/MED/1...
Helvella - the paper is firewalled. Am I missing a link?
I did a very deep dive on this a while ago, can’t lay my hands on the sources right now.
But one thing recently I read was that the only place iron will block/interact with exogenous thyroid hormones in the digestive tract - not in the blood. Early on I thought differently but there’s still a little doubt I have as I can’t recall my sources.
So wondering if you know - and if that’s true, then I don’t see how or where iron could “catch up. What do you think?!
The full paper is paywalled, I'm sorry. But I can see the abstract here:
europepmc.org/article/MED/1...
I think that the whole subject of levothyroxine absorption is inadequately researched. But my impression was that some iron can pass on from the stomach before full gastric emptying. And levothyroxine absorption can take over two hours to peak. So feasible (in my mind) that some is still in the process of being absorbed as the iron arrives. Or some iron could still be coating the gut when the levothyroxine arrives.
I agree that iron on blood is not usually thought to be an issue. But I'd reserve a final opinion until I have seen whether the hepatic portal vein could allow some interaction. That is, between gut and liver, while the iron is in whatever form it has just arrived in.
That’s what I recall reading into… which is not just where Levo and iron co-exist but what they competed for whether it was pathways for absorption or receptors and transport.
I would have to look again for my source, but I did conclude that iron and thyroid in blood don’t compete for anything. I read about it in context of Levo and iron infusions where you can take Levo and get an iron infusion without any conflict.
I would not bet my life on this but I am pretty sure, and will at some point settle it one way or the other.
Edit: also whereas the research might be light on the topic, there is a more settled science about iron metabolism on its own, and pretty good manufacturer and clinical study on Levo metabolism. So it is possible to draw conclusions I think.
Sorry? What is 1 hour?
The time it takes for the ingested Levo to get to our small intestines, and therefore for it to be safe from being blocked in the digestive process by other things we ingest.
I would imagine that varies very much from person to person. But if you're hypo 1 hour sounds very optimistic. And it would probably vary from day to day, too. Some days I feel as if my breakfast is still in my stomach at dinnertime! But I know of no way of telling for sure.
Sure, but indications are always to take Levo on an empty stomach and wait one hour before eating or drinking coffee because we know that Levo is absorbed extremely efficiently in the small intestines. There are individual variations of course but the hormone and its digestive pathway puts us in that hour ballpark.
Yes, but that's hardly the same as taking iron, which is known to bind to just about everything. Any nutrients you get in your breakfast are minute compared to iron supplements.
Oh yes I see!
I was just saying that you can take your iron at least an hour AFTER taking Levo.
As for how long to wait AFTER taking iron… yea I wait 4 hours as a rule.
But I still don't agree that you can take iron one hour after levo.
I never would … I do 4 hours around my thyroid hormones for anything.
However…. when you track the path of Levo to the point where it gets into the small intestine, and then see the pathways iron takes when ingested and ultimately absorbed, then iron (like coffee, or breakfast, or other absorption blockers) would have a pathway after a solid hour after Levo.
One could say 2 to be safe (and I say 4 because I’m conservative on just about every approach) but there is so much studied around how efficiently Levo is absorbed on an empty stomach and through the small intestines. It’s ridiculously efficient.
So although I too would never in practice, when looking at the biology and chemistry behind it clinically it can be much closer.
bnf.nice.org.uk/treatment-s...
If you look at the table on that link with the iron content of the commonly prescribed iron supplements you can see that 2mg is an extremely low dose. It might not make much difference to your iron levels at all.
Iron is such a difficult supplement to dose when timing is so very important. Another potential problem is that your 2mg of iron might interfere a little bit with absorbing your B vitamins.
When I was taking iron and thyroid hormones I would take all my thyroid hormones as soon as I woke up, then would wait until late morning or early afternoon to start taking my supplements. Since I struggle to tolerate iron salts I would take iron with my evening meal. It almost certainly slowed down my absorption of iron, but is the only way I could take it. (I have chronic gastritis.)
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