Non-coeliac gluten sensitivity doesn’t exist. Yes it does. No it doesn’t. Yes it does. Round and round we go, in an endless confusing circle of blinkered, righteous assertion.
The scramble, when the news broke properly, to be among the first to share the latest 'pro-NCGS' research on social media or secure the most hits to one’s site on the back of it was no doubt ultimately won by The Daily Mail. But others covered it and shared it too - Live GF, Medical Daily, Neal's Yard Remedies, and countless more.
The study - wordily called Small Amounts of Gluten in Subjects with Suspected Nonceliac Gluten Sensitivity: a Randomized, Double-Blind, Placebo-Controlled, Cross-Over Trial - was published in Clinical Gastroenterology and Hepatology.
This is the abstract (the full paper requires a subscription), which is all most mere mortals had to work with.
It's complex, so this is simplified. 61 self-diagnosed NCGS patents - confirmed both coeliac and wheat allergy negative - were randomly assigned to receive a gluten capsule or a rice capsule for a week, before switching to the other capsule. Symptoms at various stages were recorded.
The abstract gives the impression that gluten significantly increased symptoms in all 59 patients who completed the study. But did it? And is it evidence of NCGS?
I’ve learned, in this business, that rarely is any one study - especially a small one - a serious game changer; most are not as momentous as the recent LEAP / peanut allergy study. But what I’m yet to learn is how to critically analyse full scientific papers, so for the summary points below, I’ve three posts to thank by Laurie Laforest, Alex Leaf and Ross Pomeroy - although their interpretations differ in part from one another. Anyway, they dug deeper than I could to look at the statistics:
* Over a third of patients on the study experienced worse symptoms with rice than with gluten.
* Over a half felt their symptoms were roughly the same, whether on rice or gluten.
* Three out of the 59 had strong enough symptoms with gluten to be considered possibly gluten sensitive - that's 5% - and these appear to have skewed the overall results. (Pomeroy suggests it's 9 out of 59, but still.)
* The study, according to the researchers themselves, "does not represent crucial evidence in favour of this new syndrome".
* Strong placebo / nocebo effects were noted.
* There are question marks about participants' baseline diets.
* No blood markers for NCGS were discovered.
No, I don't understand why the abstract was so NCGS-positive either ...
NCGS is difficult to demonstrate, both as an entity and in an individual. You need to exclude coeliac and wheat allergy. You need to account for the possibility that FODMAPs - or other components, such as non-gluten proteins - are the underlying issue. You need diets that are free of potential triggers - and there are lots, including biogenic amines such as histamine, which Laforest mentions. You need repeated blinded gluten and placebo challenges and rechallenges to be certain.
And, strictly, you can only do this under clinical conditions. People are self-diagnosing NCGS, nutritional therapists are diagnosing it on the strength of unproven tests, and even the better guidelines for orthodox diagnosis are unsatisfactory.
Why? Because we don't consume gluten. We consume gluten-containing food.
Eat a peanut and feel your tongue swell? Blaming the peanut seems a reasonable conclusion, albeit not conclusive. But can you decide on which of the peanut allergens - such as the 11 'ara h' ones listed here - is responsible? Of course not.
Eat a roll and feel your belly rebel? Similarly, blaming the bread may be understandable, but singling out a particular component within the bread is a speculative jump - an unsafe assumption that is being repeatedly made.
Researchers understand this problem. Most lay folk don't, and see gluten as the only conceivable criminal.
Does it matter? It depends. Those who have found relief on a GFD won't care, and if their diet is healthy and balanced, that's great. But I think problems arise when they encourage others to follow suit, on the strength of their own, possibly flawed convictions - and do so in a cavalier way, without recommending recourse to dietetic advice, or as a harmless bit of experimentation. Are they spreading confusion and fear about a protein which, for most people on the planet, is harmless?
You can know that you feel better on a GFD, but tough to swallow as it may be, you can't know that it is the absence of gluten which is to thank for it. FODMAPs, non-gluten proteins, yeasts could be involved, as could food components introduced or increased on your new regimen. As could placebo. And nobody can fairly claim existence of NCGS on the basis of personal experience, any more than I have the right to determine the outcome of the election on the basis of my vote. One view or experience does not get to decide - those of the many, under rigorous conditions, eliminating bias and variables and other fiendish potential fly-in-the-ointments, might.
My hunch? NCGS may well turn out to be a real entity, but rarer than has been suggested. When up to 95% of a group of 60 who think they have it turn out to probably not have it, it raises question marks over self-diagnoses, which should be glaringly obvious anyway. I think other wheat proteins may also turn out to be occasional bad guys. But we'll see ...
Another study will appear. This one will find 'against' NCGS. The Mail will treat its previous coverage as if it never happened and instead accuse those trying to find a solution to their problems of being paranoid or being fantasists or of having intolerance 'all in the mind' - it doesn't matter which, so long as it makes those already feeling physically shitty feel psychologically shitty too.
This will be the nod of permission for internet trolls who love to tell individuals to get a grip, eat a pasty, to stop whining about there being no GF menu, because they are sneering know-it-nothings who get their kicks from being vile about (and sometimes towards) those with health issues or who restrict what goes into their mouths - so that these poor sods, instead of asking freely for sane health advice for fear of being derided, try their luck on the world wild web, where the likes of kinesiologists await, to tell them that yes, they are gluten intolerant, because a slice of bread supposedly makes their muscles go a bit weak.
Round and round we go.
Labels: Daily Mail, FODMAPs, non coeliac gluten sensitivity, self diagnosis, wheat intolerance