Do we have this? According to Chris Masterjohn, we don't.
Chris Masterjohn on How to Properly Interpret Ex Vivo Studies -- Gluten and Leaky Gut As an Example:
Consequently, neither Dr. Fasano's most recent study showing that non-celiac gluten-sensitive patients do not have leaky gut nor the double-blind controlled trial showing that gluten does not cause leaky gut in non-celiac gluten-sensitive patients rule out the possibility that there is some subset of non-celiac subjects, somewhere on the face of the earth, perhaps autistics, perhaps not, who actually do respond to gluten by developing leaky guts. But to my knowledge there is no solid evidence of this and if anyone knows of some, again, please post it in the comments.
But according to Aaron B.(resident paleo hacker)
If you think science hasn't already provided "undeniable evidence wheat messes you up," then I'd say you're setting the bar for "undeniable" so high it can never be reached.
Can someone show me this science Aaron B eludes to?
From what I have read, the evidence just isn't there. I suspect that evidence will be coming as more studies are done, but I can't prove it.
I have clear evidence that eating gluten grains causes me to get skin rashes. I believe that eliminating gluten has also contributed to a number of other health benefits I experience on paleo. But we must clearly distinguish between what has been established empirically and what is merely suggested by multiple lines of evidence and reasoning.
Yes, it has been proven. Look up WGA on Pubmed. It trashes the brush border of intestinal lining whether you digest gluten or not. Are there people who are somehow not affected by it? Maybe. But they have not been found yet.
We have a mechanism for direct damage and a ton of massive negative associations, but we DO NOT have a mechanism for avoiding damage or positive associations. So the logically sound thing to do is to consider wheat a toxic food and avoid it.
Is it possible that the implications of implicating gluten as being harmful to EVERYONE are too much for the scientific community and the government to be responsible for?
I mean, what would be the public response to a government statement that said gluten causes inflammation, which can lead to auto-immune diseases, heart disease, etc.
Even if there were indisputable evidence I don't see it being released.
The question you're asking can't be answered. Basically when it comes to applying science to our diets there are two approaches (I think we need to use both because there are limits in either case).
First, there's the "Gary Taubes" approach. Where he cares mostly about observables. This is close to your question: I.e., "does gluten mess up healthy people"? In this situation you need to both define "mess up" and "healthy people", and then do a study and look at the outcomes at the level of "what happened to the people".
The other approach (and where I lean), I'll call the "Mat Lalonde" approach. (I probably lean this way because I'm a chemist too.) In this approach we concern ourselves with the biochemical mechanisms: Glutens cause some types of cells to "fall apart". The types of cells that it interferes with are in the gut. When the gut lining breaks down, whole proteins get into the blood. When whole proteins get into the blood you can get autoimmune responses. Etc. Here we're talking at the chemical level. And as you're concerned maybe that doesn't happen with "healthy" people and there may not be an observable.
So back to your question, you want "scientific evidence" that gluten "messes up" "healthy people". I put the quotes in there because those terms need to be defined. Lets start from the back of the question:
"Healthy People" How do you define healthy people? There are lots of people that may appear healthy but have some weird skin rash that they wouldn't attribute to gluten, they may just call it dry skin. Or someone may have a permanently runny nose, and they just say it's allergies. So you'll need some (hopefully simple and easy to defend to your audience) metric that distinguishes between health and non-healthy people
"Messes Up" What do you mean messes up? Autoimmune problems? Seemingly random diarrhea? Chronically runny nose? Skin rashes? Bloating after eating? You need to pick the metric you're comparing in your study.
"Scientific Evidence" Given that you've defined healthy people (at a level that your audience can understand) and that you've defined "messes up" to single out 1 or 2 (at most) illnesses. You need to split your people up into multiple groups, control their food, and hopefully not have any other confounds in your study.
I'm stopping here before this gets longer, but in reality science is hard, and it's even harder to get right. That's why you'll never find a "definitive" study either way that something is good or bad for you, you have to look at how the good and bad were defined in THAT study. That's why I generally lean towards the mechanistic approach, we can understand what the molecules are doing and then extrapolate and say "if I don't eat gluten, I won't damage my gut and get all the problem that come along with a damaged gut". Then, as I did, I quit eating gluten and things are better. So, FOR ME, I'm happy.
One study (Key's Seven Country Study) is the only study out there that said "fat is bad" and then people interpreted it as the definitive study that and said that fat was bad. There was no mechanistic given. Just "fat messes up people" and everyone bought it.
I never thought I had any problems with gluten and I absolutely love bread so I've eaten I'm sure, more than my fair share over the years. That being said, a couple of years ago when I first read about paleo, I cut all grains and bread out for about 2-3 months before the occasional sandwich started to creep back into my diet. It was at that point when I started paying attention to how I felt whenever I would eat bread/gluten. I felt bloated, sluggish, and just overall shitty. Since then, knowing that gluten does have an effect on me, it has still been a struggle to not slip back into eating it periodically.
And now, I turned 40 last week and my present was finding out I have developed an autoimmune disease. I cannot say that grains or gluten are to blame but it certainly is possible and no one else in my family has ever had an autoimmune disease so I can't trace it in genes either.
How would you go about proving this? You'd need a group of healthy people who've never (or not recently) eaten gluten for a baseline before giving half of them gluten and testing both for differences.
Or you could do what most of us have done and take people (us) who have been eating gluten all their lives, remove the gluten from their diets, and then find out if they're healthier than they were eating gluten. Everyone here who feels better when they're not eating gluten raise your hand. Not exactly scientific, but if you're waiting around for the scientific community to do that study, don't hold your breath.
What's Worse... Gluten or Sugar? 10 Answers