It is most likely due to changes in applicable laws.

I doubt that Amazon have that much sway over products.
They may be able to restrict you listing those products on their site, but Amazon won’t have any say in whether you can import this item into Europe.
You might be advised to reopen your case and try to reach a rep who can give you a more comprehensive answer, otherwise why not email the Executive team and ask them for an explanation?
managingdirector@amazon.co.uk

Yes - Amazon UK FBA has been shipping my collagen from the UK to Europe for almost 3 years but have suddenly stopped and customers are trying to buy this item (as before) but are now seeing a red buy box message saying "item does to ship to… Spain…Denmark… etc

All of our collagen ASINs have stopped being shipped to Europe and one of our other supplements too leaving just one that has not been restricted yet.

As for our health claims and labelling - because we are selling on .co.uk our labels conform. If Amazon then ship an item to Europe or a buyer chooses to buy a British product, then the labels only have to conform to EU regs. If/when we start selling on the .it .es .fr and .de websites and warehousing our stock in Europe, then our labels etc have to be EU compliant, including languages.

But all the while we are a UK company selling products via a UK platform we only have to conform to UK regs.

So, doe ANYONE know why Amazon have stopped shipping collagen / supplements into Europe?

This is very helpful thank you but it does not explain why our marine collagen and our activated charcoal ASINs are also not being shipped to Europe now?

No, made in totally different places. Have opened a case log but was hoping other collagen sellers out there (who Ican see are also being affected) may know something. Thanks everyone anyway.