I don't think it is about taking anything specific to improve it. It is about not doing things that damage it. The body can take care of itself as long as we do not damage it and eat proper nutrients so the building blocks are there for the body to produce what it needs naturally.

What damages it? High blood sugar spikes. High blood sugar spikes does a lot of not so good things to various organs including the glycocaylx.

Eating a diet that avoids high blood sugar spikes I think would be helpful. Eating foods with adequate amounts of collagen I would think would be helpful so the building blocks would be there for the body to maintain the glycocaylx. Gelatin has lots of collagen (but not the kind loaded with sugar - sugar causes raised blood sugar).

My wife and I use some collagen and gelatin in our morning coffee to make sure we are getting enough in our diet. Does it help us in any way? I have no idea. We probably get enough collagen in the foods we eat. But it smooths the coffee out kind of like a coffee creamer would and I am sure it doesn't hurt us other than the pocket book a little. We do it just to make sure we are getting adequate amounts but probably do not need it at all.