Cereals fortified with Iron

[Observer]

If a cereal is fortified with iron would it interfere with the absorption of Thyroxine medication taken 30 minutes prior?

[Lalatoot]

If you are OK on levo then don't worry. It might mean that you take slightly higher dose of levo than if you didn't have cereal. Presume you are taking it with dairy?

If you need to be careful how you take your levo then why not take it in the afternoon or t night away from cereal.

[Observer in reply to Lalatoot]

Just had symptoms of being Hypo again after eating fortified cereals 30 minutes after my Levo (leg cramps, waking and feeling that I had no sleep etc). I have stopped the cereal and gone back to my normal porridge and symptoms have subsided. Just wondered if the Iron was causing the issue.

[SeasideSusie Remembering]

Levo should be taken on an empty stomach, one hour before or two hours after food, with water, and water only for one hour either side. So the fact that you are eating 30 minutes after taking your Levo is affecting it's absorption anyway. Plus the milk will too as it contains some calcium.

[Observer in reply to SeasideSusie]

Going to have to get out of bed 30 minutes earlier than normal 😭

[SeasideSusie Remembering in reply to Observer]

Or maybe change the time you take your Levo. I regularly need to visit the bathroom in the early hours of the morning, so I take mine then. Keeps it away from breakfast, coffee, supplements.

[Observer in reply to SeasideSusie]

I think that makes sense

[hemp66 in reply to Observer]

I had an awful time Drs where great looked at everything from head to toe could not solve problems so I checked up on levo.found out you need a good empty stomach ,yes I took mine before breakfast about an hour before ,so now stop eating at 20.30 then only drink take levo. Last thing I do making it at least 2 hours after my last intake of food , within 2days I had my life back now been 3 months and still feel great . hope this makes sense .x

[Observer in reply to SeasideSusie]

So would the Iron be causing an issue as well?

[SeasideSusie Remembering in reply to Observer]

I don't use iron fortified cereal so I have no idea how much iron it contains, so can't comment on that. But considering iron should be taken 4 hours away from Levo, I would check the amount of iron in it in your cereal.

[Observer in reply to SeasideSusie]

3.6mg in a standard serving.

[SeasideSusie Remembering in reply to Observer]

It's a long way from prescription strength iron tablets but fairly close to Spatone (5mg per serving) so I guess it could affect absorption of Levo.

[Observer in reply to SeasideSusie]

Yes been eating it for several weeks so was probably affecting my Levo absorption. Thanks for the advice everyone 👍

[Aslangal in reply to Observer]

I do what SeasideSusie does ... leave a glass of water and tablets ready so you can take them if up in night. I found this avoids any interference with any food or drink and then I don’t have to wait ages to have breakfast 🍳!

[helvella Administrator Thyroid UK in reply to Observer]

3.6 milligrams sounds a tiny amount - but it is massively more than the levothyroxine you are taking. By weight, probably a few hundred times more. By number of molecules, an even greater ratio.

If you wanted to bind 100 micrograms of levothyroxine in a test tube, you would need less than 100 micrograms of ferrous sulphate.

[helvella Administrator Thyroid UK]

You do not say which form of iron is used in the cereal but it is probably not very important. So far as I am aware, most forms of iron could interfere with levothyroxine.

Further, in the case of any breakfast cereal, the actual cereal ingredient (wheat, corn, or whatever else) can also affect levothyroxine absorption. As can the milk most people pout over their breakfast cereal.

Ferrous Sulfate Reduces Thyroxine Efficacy in Patients With Hypothyroidism

N R Campbell 1 , B B Hasinoff, H Stalts, B Rao, N C Wong

Affiliations

• PMID: 1443969

• DOI: 10.7326/0003-4819-117-12-1010

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.

pubmed.ncbi.nlm.nih.gov/144...

[Observer in reply to helvella]

The cereal is fortified with Ferrous Sulphate so would tally up with that report.

[helvella Administrator Thyroid UK in reply to helvella]

Meant to add, with iron it is suggested a gap of at least four hours - before and after levothyroxine.

[Observer in reply to helvella]

Yes I have stopped eating it at the moment due to symptoms I was getting.

[Chippysue]

I would be far more concerned about the glyphosate, GMO and gluten in cereals

[Observer in reply to Chippysue]

Yes not the healthy breakfast it appears to be