Vitamin c increases absorption of Levothyroxin

[janeroar]

Wondered if anyone had seen this and what this means In terms of whether we should be taking vitamin c?

ncbi.nlm.nih.gov/pubmed/246...

Effect of vitamin C on the absorption of levothyroxine in patients with hypothyroidism and gastritis.

Jubiz W, et al. J Clin Endocrinol Metab. 2014.

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Abstract

BACKGROUND: Malabsorption of l-T4 is a major clinical problem. Changes in gastric pH caused by several medical illnesses are associated with difficulties in the control of patients with hypothyroidism receiving the hormone. Means to correct these alterations would be of clinical value.

OBJECTIVES: Our objective was to study the effect of vitamin C on the absorption of l-T4 in patients with hypothyroidism and gastritis.

DESIGN: Thirty-one patients with hypothyroidism, 28 females age 47.5 ± 13.5 (mean ± SD) years and 3 males age 55.7 ± 11.2 years ingested the dose of l-T4 in 120 mL water containing or not containing 500 mg vitamin C in a solution of pH 2.9 ± 0.1 (mean ± SD). Serum concentrations of free T4 and TSH were measured at the end of 3 periods of 2 months each, 2 controls and 1 vitamin C. Serum total T3 was measured in 16 of the patients, before and at the end of the vitamin C period. Serum TSH and free T4 and T3 were measured by a solid-phase, enzyme-labeled chemiluminescent competitive immunoassay All patients had gastrointestinal pathology and were not in good control when taking l-T4 before the study, and 23 had autoimmune thyroiditis or idiopathic hypothyroidism. The median l-T4 dose was 100 μg with an interquartile range of 50 μg. The protocol was reviewed and approved by our institution's ethics committee. Patients were asked to sign a written consent to participate in the study.

RESULTS: Serum concentrations of TSH, free T4, and T3 improved while on vitamin C. Serum TSH decreased in all patients (control, 11.1 [10.5] μIU/mL, median [interquartile range]), vitamin C 4.2 (3.7) μIU/mL, P = .0001), and it was normalized in 17 patients (54.8%). The average decrease was 69.2%. Serum T4 was higher with vitamin C in 30 of the 31 patients (control, 1.1 [0.3] ng/dL; vitamin C, 1.3 [0.3] ng/dL; P < .0001), and serum T3 increased as well in all 16 patients in whom it was measured (control, 60.5 [16.5] ng/dL; vitamin C, 70 [21] ng/dL; P < .005).

CONCLUSIONS: In patients with hypothyroidism and gastrointestinal pathology, vitamin C improves the abnormalities in serum free T4, T3, and TSH concentrations. This approach is helpful in the management of these patients.

PMID 24601693 [Indexed for MEDLINE]

[SeasideSusie Remembering]

Vit C is a good supplement for us to take as it helps support the adrenals. You'll often see it recommended, 2000mg daily, or more if you want, up to bowel tolerance.

[janeroar in reply to SeasideSusie]

Thanks. I’ve just started taking 500mg which is a large dose. I often wonder about whether it’s good to take v large doses of vitamins. I know for eg vitamin c can turn from being a antioxidant to pro-oxidant at high levels.

[janeroar in reply to janeroar]

I’m not sticking to vitamin supplements because of this worry about overdosing and I know I need to take them because some of my levels are low. Hard to know what are the right quantities. It seems mad to take for eg 5000% RDA of vitamin b12 which is one of the vitamin supplants I have lying around! I read recently that high levels of vit D are toxic. You have lots of experience about this SeasideSusie, any advice?

[SeasideSusie Remembering in reply to janeroar]

Jane

There are some vitamins that, when taking too much, the excess gets stored, so it is important to keep an eye on levels and tailor the dose to what is needed to keep within range so as to avoid toxicity level. All fat soluble vitamins come under this - A, K, E, D, also iron.

With water soluble vitamins the excess gets excreted through urine - B vitamins, Vit C.

500mg Vit C is not a large dose.

There is a lot of information and misinformation on the internet, we have to sort the wheat from the chaff.

Getting information from reliable sources is a good idea. As far as I am concerned, Dr Peatfield (if you've not heard of him) is probably the most eminent thyroid doctor in the UK, who gave up his license so that he could treat his patients properly rather than be restrained by the NHS. In his book Your Thyroid and How To Keep it Healthy, he lists important vitamins and minerals we Hypos would benefit from. He advises Vit C 2000mg daily. That's good enough for me. Vit C supports adrenals, thyroid and adrenals work together.

[janeroar in reply to SeasideSusie]

Thank you that’s really helpful. Really good to know. I really appreciate your advice and I’ll get his book.

[helvella Administrator Thyroid UK]

If taking vitamin C to enhance absorption of levothyroxine, I suggest making sure it is vitamin C powder - not, for example, orange flavoured effervescent tablets. The reason, quite simply, being that the other ingredients could also impact absorption - and quite possibly hinder it.

[janeroar in reply to helvella]

Good thinking thanks. There’s some vitamin c that’s ‘buffered’ ie non acidic. Would that be ok?

[helvella Administrator Thyroid UK in reply to janeroar]

The paper you quoted refers to 500 mg vitamin C in a solution of pH 2.9 ± 0.1

I suspect that level of pH would only occur in "normal" ascorbic acid - not a buffered form. However, the paper doesn't seem to state that it is the acidity that has the helpful effect - so who knows?

[janeroar in reply to helvella]

Thanks that’s good to know

[SlowDragon Administrator in reply to janeroar]

No I would suspect not, it's usually buffered by adding calcium. Which you don't want to take anywhere near Levothyroxine

To improve absorption the gut needs to be acidic. That's most likely proper acidic vitamin helps

Many hypothyroid patients have low stomach acid. Sadly still many Medics deny low stomach acid even possible. There's no recognised NHS test.....therefore it can't exist in their view

Masses of posts about low stomach acid on here

healthunlocked.com/search/%...

Also some links

thyroidpharmacist.com/artic...

drmyhill.co.uk/wiki/hypochl...

scdlifestyle.com/2012/03/3-...

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

[janeroar in reply to SlowDragon]

Thanks for this SlowDragon. Will look at these links, very helpful.

I have low stomach acid and don’t know whether that’s why I get heart burn from eating anything too acidic? I tried drinking cider vinegar and it gave me heartburn, ditto lemons. Is this common?

[helvella Administrator Thyroid UK in reply to SlowDragon]

However, levothyroxine is not very soluble in acids - it is more soluble in alkalis.

This paper describes causing the precipitation of thyroid hormone from solution by acidifying it - jbc.org/content/72/1/213.fu...

Although we regularly discuss stomach acidity - we rarely discuss the alkalisation in the gut after the stomach.

[janeroar in reply to helvella]

Hi Helvella you know an awful lot more than me about this. So where does this leave us Re vitamin c and now low acid in stomach do you think?

[helvella Administrator Thyroid UK in reply to janeroar]

Keep it simple - ascorbic acid has been shown to improve absorption. Quite why or how is not explained - nor does it actually matter! Just go with what the paper says - put 500 milligrams of ascorbic acid in 120 millilitres of water - mix well.

It reads as if they dispersed the levothyroxine tablet in that ascorbic acid solution - but not 100% clear. Probably doesn't make much difference whether the tablet is dispersed or simply swallowed with the ascorbic acid solution.

[janeroar in reply to helvella]

I agree it does seem to suggest the thyroxine was mixed in with the vitamin c. That seems to make sense. Might try this and report back in a few weeks !

[janeroar in reply to helvella]

Hi Helvella came across your post on vitamin C and B12 from 7 years ago! You e been doing this for a long time!! Maybe I should be careful about mixing vitamins up. Minefield!

.......

I have just been reading the USA Medline paper on B12. For all those who do or are thinking about vitamin B12 supplementation, it is well worth a visit here:

nlm.nih.gov/medlineplus/dru...

One specific point that it makes, something I had failed to realise, is this:

Vitamin C

Early research suggests that vitamin C supplements can destroy dietary vitamin B12. It isn't known whether this interaction is important, but to stay on the safe side, take vitamin C supplements at least 2 hours after meals.

Makes me seriously question multi-vitamins that contain both.

Also worthy of note:

For vitamin B12 deficiency or pernicious anemia: cyanocobalamin doses of 300-10,000 mcg (microgram) daily have been used. However, some evidence suggests that the most effective oral dose is between 647-1032 mcg/day.

So the typical dose suggested here of 1000 mcg seems in line - for as long as you are deficient. But maybe a less frequent intake when you switch over to maintenance dosing.

Rod

[helvella Administrator Thyroid UK in reply to janeroar]

Jolly annoying - I can't find that post! You don't have a link to it, do you?

[janeroar in reply to helvella]

Just replied to original post as couldn’t find a way of forwarding it to you. Did you get it?!

[janeroar in reply to helvella]

From 7 years ago!!!

healthunlocked.com/thyroidu...

[helvella Administrator Thyroid UK in reply to janeroar]

Thanks - had been away from computer for a while - got both thank you very much!

[Jazzw]

The bit that’s missing for me (although maybe it’s in there and I skimmed over it??) - is any details about whether the patients felt better? Yes, Vit C seemed to impact TFTs. But did the patients feel any better for taking the Vit C - or did it provide a clinical incentive for reducing levo doses?

[helvella Administrator Thyroid UK in reply to Jazzw]

I think it is all summed up in this one sentence:

This approach is helpful in the management of these patients.

Why on earth would you ask if the patients felt better - or had any opinion whatsoever? Our [authors'] management of them was easier, that was what mattered.

[Jazzw in reply to helvella]

Not sure how it’s helpful at all. If the patients didn’t actually feel any better then so what? But hey, maybe they did... Let’s be optimistic. If Vit C does help us make better use of the levo we throw inside our bodies, then that’s a good thing.

Although - won’t that simply be because Vit C increases iron absorption - and iron assists in the conversion of T4 to T3?

[helvella Administrator Thyroid UK in reply to Jazzw]

As I understand, it is the having vitamin C/ascorbic acid in your stomach along with the iron supplement that helps absorption. And as we all know to take iron supplements four hours or more away from levothyroxine, I don't think the two effects could combine. However, nothing to stop someone taking vitamin C with their levothyroxine, and more vitamin C with an iron supplement - four hours later!

[janeroar in reply to helvella]

Grim isn’t it. Hence the need for this forum because there are too few doctors who are focussed on patients. It’s not necessarily their fault they’ve been taught badly

[janeroar in reply to Jazzw]

Good question it doesn’t ask how patients FEEL! Flipping heck that’s so basic and yet missing from a lot of medical white papers. As if numbers in a lab report are more important than how people actually feel. Would be interesting to know wouldn’t it.

[KT77]

Does this mean I can take my thyroid medication with orange juice then ? : ) Cos that would be cool.

[Saya85]

All I know is vitamin c was a game changer for me recently. Adrenals were improved massively and I think the acidity of the form I was taking helped with low stomach acid and meals.

However I have been feeling as if I’m sligjtly over medicated now with thyroid ! So maybe there’s something to it and I need a lower dose? Lol happy days. Having bloods done tomorrow so will see what results say

[janeroar in reply to Saya85]

Which brand of vitamin c did you use?

[Saya85 in reply to janeroar]

Tbh I used the effervescent tablets with zinc. I know I know- not the greatest but I think it was the effervescence that helped the stomach acid too.

However now I think about it I do remember reading that Apple cider vinegar or lemon water with thyroxine helps absorption... but someone above posted thyroxine absorbed in alkaline envt? Bit confused.

But I would def recommend vit C for us hypothyroids. Up to 1000mcg and plenty of water 🙌🏻

[janeroar in reply to Saya85]

Thanks Saya that’s really helpful.

I’m going to try Vit C and also slowly up my cider vinegar consumption.