Over-the-counter protein supplement resulting in impaired thyroxine absorption in a hypothyroid patient

[helvella]

There are so many products - foods and supplements - very often heavily promoted or "fashionable", about which we do not know enough. This example should not be a surprise as it is known that dairy can interfere with levothyroxine. Nonetheless good to see it being reported.

Endocrinol Diabetes Metab Case Rep. 2021 Jul 19;2021(21-0070):EDM210070.

doi: 10.1530/EDM-21-0070.

Over-the-counter protein supplement resulting in impaired thyroxine absorption in a hypothyroid patient

P A D M Kumarathunga 1 , N S Kalupahana 2 , C N Antonypillai 1

Affiliations

• PMID: 34280893

• DOI: 10.1530/EDM-21-0070

Free article

Abstract

Summary: Whey protein is a popular dietary supplement that is claimed to provide multiple health benefits. It has been shown to delay gastric emptying and impair ileal nutrient absorption. Additionally, some of the other additives like papain enzyme, soy lecithin in these protein supplements could interfere with L-thyroxine absorption. There is no evidence in the literature for the effects of protein supplements on L-thyroxine absorption. Herein, we describe a case of a 34-year-old lady who was on endocrinology follow up for primary hypothyroidism with stable thyroid-stimulating hormone (TSH) levels within the normal range while on L-thyroxine with a dose of 125 µg daily for the last 3 years, presenting with mild hypothyroid symptoms and elevated TSH level following a recent introduction of a protein supplement by her physical care adviser. Her treatment adherence and ingestion technique were good throughout, she was not on other medications or herbal remedies, there were no other changes in her food pattern or features suggestive of malabsorption, she was not pregnant, was taking the same L-thyroxine brand and TSH test was done from the routine lab. Since the only factor which could have contributed to the deranged TSH levels was the recent introduction of the whey protein supplement, we advised her to stop the protein supplement while continuing the same dose of L-thyroxine. Her TSH level was repeated in 6 weeks and was found to be normal (1.7 mIU/L). Our case report demonstrates that over-the-counter protein supplements could interfere with L-thyroxine absorption. Therefore, patients on L-thyroxine should be cautious when taking them.

Learning points: Over-the-counter protein supplements could interfere with oral L-thyroxine absorption. The underlying mechanism could be the effect of whey protein by delaying gastric emptying and reduced responsiveness of organic anion transporters in the ileum, and there may be a contribution from other additives like papain and soy lecithin present in these supplements. When there is an elevation of previously stable thyroid-stimulating hormone (TSH) value in a hypothyroid patient on oral L-thyroxine, the patient's assessment should include inquiring for a recent introduction of protein supplement, in the absence of other well-known risk factors. Discontinuation of protein supplement results in normalization of thyroid function tests. Patients on oral L-thyroxine should be cautious when taking over-the-counter protein supplementation.

pubmed.ncbi.nlm.nih.gov/342...

Full paper freely available here:

edm.bioscientifica.com/view...

[jgelliss]

It's very interesting. Thank you Helvella for another very interesting post. I was wondering would rice protein be one of the proteins to avoid as well ?

[J675]

Hmmm, I wonder if that applies to ALL protein supplements or just whey protein? I already avoid whey protein as I try to stick to a low FODMAP diet and due to the lactose content, I never feel good after having some. However, I do have a small amount of callogen protein in my morning porridge, although this is usually at least two hours after my levo.

[Adam10]

Did it mention if TSH levels were affected if whey protein was taken at the same time or at a time close to taking the daily dose of T4? If so, that would be easy to avoid the problem.

However, the article seems to imply that TSH levels were affected regardless of the time when the whey protein was taken?

[helvella Administrator in reply to Adam10]

The article leaves lots of questions open.

[Emj001 in reply to Adam10]

Maybe a dairy problem?

[Serendipity__]

Interesting! About two months ago for the first time in my life I ordered a big bag of whey protein from the US - because it had no other additives at all - pure protein. And it actually did so much good for me - my muscle aches were completely gone, I could do so much more in sports and also the impossible happened - lost 1.5 kg in a month. I already had hypo symptoms before it, but it alleviated them so well. Not to mention hair and skin. Also I always mixed it with milk. Sometimes I wouldn’t feel like eating anything at all and discomfort in GI, so I would mix a glass of milk with this powder and go to sleep feeling satiated and without discomfort of a full meal.

[Batty1]

I could never eat whey the stomach pains but I wonder if this applies to all protein products?

[helvella Administrator in reply to Batty1]

Unless proved otherwise, I think we have to retain some suspicion about all high protein products. (Not all products which contain protein, just these high protein products.) But that is just suspicion - not a basis for making decisions.

[Batty1 in reply to helvella]

Your probably right. Why in the world don’t Endo's tell us this stuff…ugh.

[endomad]

I have used a good quality whey protein powder for last 10 years or more. I eat low carb. I cant face breakfast but get dizzy if I dont so a protein smoothie does the trick. If I am too busy at lunch a protein, chia seed and fruit smoothie keeps me going. If I fancy something sweet at night, I mix strawberry protein into plain greek yogurt its delicious or have a protein hot chocolate. I am on T3 only, it only mentions levo but to be honest so many body builders use whey and we know how important T3 is for them. It has certainly never slowed my gastric emptying first thing in the morning. I make milk kefir that I use in protein smoothie that prob keeps my gastric/gut health in good shape.

[ginid in reply to endomad]

Hi Endomad, I wonder if you are in the UK and if so please are you able toshare the brand of your whey powder . I was hoping to get some decent quality whey for my 19 year old daughter who is so skinny (no thyroid issues for her as far as I'm aware....yet!!).She does eat well but could probably do with a bit more dairy!When I was her age I too was skinny (guess it's just our metabolism) She wants to gain weight to boost her confidence and I was wanting her to try whey protein shakes to try and gain weight! Thanks

[endomad in reply to ginid]

I use 'my protein' I like the dark chocolate one, natural vanilla, chocolate truffle, blueberry cheesecake and specaloos. Some flavors are a bit sweet for me. I use the chocolate collagen powder to sweeten my coffee it has helped my joints. I buy the natural peanut butter which is great in vanilla smoothie. They also do a weight gain formula [which I don't need] this brand has a lot less additives than most whey protein, they have lots of money off offers, so I stock up when my fav products half price x

[ginid in reply to endomad]

Thank you very much for your reply. I will try this for her!x