Monday, March 14, 2011

Gluten-Free January Survey Data, Part II: Health Effects of a Gluten-Free Diet

GFJ participants chose between three diet styles: a simple gluten-free diet; a "paleo light" diet diet that eliminated sugar and industrial seed (vegetable) oils in addition to gluten; and a "paleo full monty" diet that only included categories of food that would have been available to our pre-agricultural ancestors. The data in this post represent the simple gluten-free diet group, and do not represent the other two, which I'll analyze separately.

To get the data I'll be presenting below, first I excluded participants who stated on the survey that they did not adhere to the diet. Next, I excluded participants who were gluten-free before January, because they would presumably not have experienced a change from continuing to avoid gluten. That left us with 53 participants.

For each of these graphs, the vertical axis represents the number of participants in each category. They won't necessarily add up to 53, for several reasons. The most common reason is that for the questions asking about changes in health conditions, I didn't include responses from people who didn't have the condition in question at baseline because there was nothing to change.

Question #1: What is your overall opinion of the effect of gluten free January on you?

Participants had a very positive experience with the gluten-free diet. Not one person reported a negative overall experience.

Question #2: Did you note a weight change at the end of gluten free January?

And here are the data for people who described themselves as overweight at baseline:

Two-thirds of people who were overweight at baseline lost weight, and only one person out of 37 gained weight. That is striking. A number of people didn't weigh themselves, which is why the numbers only add up to 37.

Question #3: Before January 2011, did you have a problem with intestinal transit (frequent constipation or diarrhea)? If so, did your symptoms change during the month of January?

Responses are heavily weighted toward improvement, although there were a few instances where transit worsened. Transit problems are one of the most common manifestations of gluten sensitivity.

Question #4: Before January 2011, did you have frequent digestive discomfort (pain, bloating, etc.)? If so, did your symptoms change during the month of January?

Digestive discomfort was common, and the gluten-free diet improved it in nearly everyone who had it at baseline. I find this really impressive.

Question #5: Before January 2011, did you have acid reflux? If so, did your symptoms change during the month of January?

Acid reflux responded well to a gluten-free diet.

Question #6: Before January 2011, did you have a problem with tiredness/lethargy? If so, did your symptoms change during the month of January?
Lethargy was common and generally improved in people who avoided gluten. This doesn't surprise me at all. The recent controlled gluten study in irritable bowel syndrome patients found that lethargy was the most reliable consequence of eating gluten that they measured (1, 2). That has also been my personal experience.

Question #7: Before January 2011, did you have a problem with anxiety? If so, did your symptoms change during the month of January?

Anxiety tended to improve in most participants who started with it.

Question #8: Before January 2011, did you have a problem with an autoimmune or inflammatory condition? If so, did your symptoms change during the month of January?

Autoimmune and inflammatory conditions tended to improve in the gluten-free group, although one person experienced a worsening of symptoms.

Question #9: If you ate gluten again or did a gluten challenge after gluten free January, what was the effect?

Just under half of participants experienced moderate or significant negative symptoms when they re-introduced gluten at the end of the month. Two people felt better after re-introducing gluten.


I find these results striking. Participants overwhelmingly improved in every health category we measured. Although the data may have been somewhat biased due to the 53% response rate, it's indisputable that a large number of participants, probably the majority, benefited from avoiding gluten for a month. At some point, we're going to compile some of the comments people left in the survey, which were overwhelmingly positive. Here's a typical comment in response to the question " In your own words, how would you describe your January 2011 experience" (used with permission):
Amazing! I would recommend the experiment to anyone. I felt completely more alert, and less bloated. When I ate some gluten at the close of the experiment, I felt gross, bloated, and lethargic.
I think it's worth mentioning that some participants also eliminated other starches, particularly refined starches. Judging by the comments, the diet was probably lower in carbohydrate for a number of participants. We may try to assess that next year.


Becky said...

Fascinating! Thank you.

We were grain free during January, which is a huge difference from merely gluten free. I actually think you can damage yourself with those starchy faux baked goods and pasta!

We have kept going with no grains, no veg oils, no sugar. We don't snack. Weight, mood, energy levels all seem to be optimizing.

I don't think "reborn" is too strong a word for how we feel. There don't seem to be any compelling arguments for returning to the old diet.

Anonymous said...

Um, Stephen, you surveyed a group of paleo and traditional diet true believers about how strictly following their diet improves their lives? And got positive results? Let's get back to science, soon...

Ruth Almon said...

Although the numbers weren't high, some people reported feeling worse on some scales. Any idea what could account for someone feeling worse?

Tucker Goodrich said...

@slowfit: Pay attention: "Next, I excluded participants who were gluten-free before January, because they would presumably not have experienced a change from continuing to avoid gluten. That left us with 53 participants."

If they were "paleo ... diet true believers" they would have been excluded, because they already would be gluten-free.

This is not great science, as Stephen pointed out at the beginning, because all the participants were self-selected. But it's still informative.

ett094 said...

You said you excluded people who started but did not finish the gluten free month. How many of those people were there?

Ned Kock said...

Thanks much Stephan. Strong evidence of effects here, indeed. Even with the possible psychological effect, we have something serious going on here. This is consistent with the idea that wheat is not only detrimental because it displaces animal foods: I still think that wheat refining plays a major role.

FredT said...

Thanks for conducting the survey.

Your blog has stimulated a session of me talking to myself that went something like this:
Gluten-Free Planet says that humans do not have the enzymes to digest gluten anyway, so why would I eat it? Something more to feed gut fauna? Produce gas, or get into the gut wall, and stimulate anti-bodies?

You do not need more carbohydrate usually accompanying the gluten. So why would I want to eat any ground flours that may contain gluten? Sensory stimulation, taste? Good tasting poison.


But what do I know.

Laura said...

@justdoinglife: I would not be surprised to find that some humans have developed the ability to digest gluten. I believe that northern European ancestry is somewhat protective with respect to diabetes; also humans' ability to digest milk and cheese varies widely. I did not participate in gluten-free January, but I've been trying it. I seem to have no ill effects from gluten at all, but my energy level seems to be somewhat higher without it.

Becky said...

Sports team (yay, us) and religious (only believe) metaphors are pretty meaningless applied to diet.

In his interesting book, Deep Survival, Laurence Gonzales writes that the quality most likely to result in survival is the ability to adjust to new data.

I know personally about a dozen people who keep taking Nexium, NSAIDs, statins, supplements, and treatments, and endure feeling suboptimal much of the time ... but won't consider modifying their diet.

Will grain free hold up for us over the long term? Still observing.

Stephan Guyenet said...

Hi Slowfit,

I don't think most of the people we surveyed were "true believers." As Tuck pointed out, I only considered the group that was not gluten-free at baseline. This was not the equivalent of asking vegans (or raw foodists, etc) "are you healthier on your current diet"? It was a self-directed intervention in people who were not gluten-free at baseline. These were people who were interested to see what effect avoiding gluten had on their lives. Reading the comments they left, many of them started off with low expectations.

I think it's fair to say that they were motivated and hopeful, which I'm sure contributed to the positive outcome. So I do think there's a grain of truth to what you're saying. But as I often say, the problem is usually not in the data, it's in the interpretation. We can't use these data to say "gluten causes lethargy, digestive and inflammatory disorders", but we can say "a motivated person who adopts a gluten-free diet has a good chance of seeing improvements in several categories of health problems." And we can also hypothesize that gluten per se contributes to some of those problems, although we need controlled studies to test that hypothesis.

Stephan Guyenet said...

Hi Porcupine,

In any study, there will be statistical variation. You always get a distribution of outcomes. Perhaps some of those people replaced gluten with another food that they react to, or reduced their carbohydrates to a level that their metabolism didn't like. Or perhaps they just had a bad month and it would have happened anyway. The data can't rule out the possibility that they felt worse because there's something about eating gluten that was actually good for them, but I find that unlikely.

Hi ett094,

There were only two people who stated that they "ate gluten most of the time". I included people who were "gluten-free most of the time" or better.

Hi Ned,

Thanks. I agree, the strength of the effect makes it much more believable.

Nell said...

I was in slowfit's category of true believer, so I couldn't participate in the survey since I've been gluten free since 2008.

But I think it's important to note that almost no one wants to feel effects of gluten! I mean, sure, I was happy to have a concrete way to feel better, have more energy, no bloating, no GI trouble etc etc. That is wonderful. But when I trialed going GF, I fervently hoped it would not turn out to be a problem, because I was so devoted to it.

And I was living in France, so the gluten I had to give up was really really good. Ah, fougasse!

I'm no study designer but it seems to me that the fact that at least some participants were likely hoping to find no effect makes the effect even bigger.

Roberto said...

Instead of eliminating gluten entirely, what would have happened if the participants had of tried the following scenarios instead?

- Eliminate all refined, bleached, pesticide sprayed, hybridized, industrial white flour in favor of organic, unbleached flour

- Eliminate all industrial white flour in favor of organic, unbleached, whole-grain flour

- Eliminate all industrial white flour in favor of organic, unbleached, whole-grain flour prepared strictly through the sourdough method

- Eliminate all industrial white flour in favor of pre-green revolution heritage varieties of wheat such as kamut, red fife, and einkhorn

- Switch from wheat to rye

It makes little sense to point the finger at gluten when so many considerations haven't been taken into effect.

And many of the participants eliminated gluten in the context of a complete paleo-diet overhaul. Countless factors could have led to these improvements.

Debbie B in MD said...

Those all seem like great studies for you to take up. Great ideas. Your result smay be very interesting, but as for the statistics from Stephen's survey, the responses seem very heavy to the side of gluten-free making a very real difference. I did not participate because I wasn't aware of it. I have been gluten free since January 17th and have been able to stop the muscle relaxants for fibromyalgia and acid-reflux medicine as well. It has made a tremendous differnce. Why be so negative? That can't help anything. Yes, I am a scientist and no this doesn't follow the steps of the scientific method, but kudos to Stephan for putting this out there.

Stephan Guyenet said...

Hi Roberto,

I don't know what would have happened if they had gone on a gluten-free diet while standing on their heads, or replaced gluten with swiss chard or fava beans. There are only so many questions one can ask in a single study.

The data in this post do not include people who went paleo, as I explained in the post. These data were from people who went gluten-free only. I'll consider the paleo group in a later post.

Roberto said...


Sorry, I didn't realize that this data only represents the non-paleo gluten-free group. That makes the results more intriguing.

Debbie B,

"Why be so negative? That can't help anything"

I'm sorry if my question seemed negative to you. It wasn't my intention to be negative nor optimistic, just discerning.

terrence said...

Roberto, on March 15, 2011 at 4:08 PM

Gluten is a protein found in WHEAT (including KAMUT and SPELT), RYE, BARLEY, MALTS and TRITICALE; and in other foods derived from these grains.

Might-o'chondri-AL said...
This comment has been removed by the author.
Water Max said...

Very interesting data, Stephan. I'm still very much dependent on gluten products for my breakfast (breads) and I'm not really sure what I can substitute that with that doesn't take too long to prepare in the morning. Any suggestion is welcomed. Thanks.

jewiuqas said...

Well, gluten is obviously an enemy, that much is clear from the analysis of the gluten-free January trial (if it is fully unbiased). But is gluten the enemy number one? I have not participated, because I feel all right with my sourdough rye-bread, and it would be too time-consuming to go bread-free (I have tried buckwheat bread, but it is not really what I would call bread, it is more like cake pastry).
I haven’t participated furthermore, because, I think, there are so many other substances that one should try to eliminate from one’s diet before having a go at becoming gluten-free. At the moment I am trying hard not to consume any added sugar, and to minimize the consumption of food additives with special regard to preservatives. It is already 20 years, or so, that I haven’t bought any refined sugar, but on examination I had to realize that I still consumed con-siderable amounts in less obvious forms. Not only ketchup and soups, but even sausages contain some form of added sugar, like dextrose, fructose… So I am having a rather hard time trying to redesign my dietary habits. I would propose to someone more at home in blog-making and similar stuff, to organize say a sugar-free April, or an additive-free May. The main purpose of such an initiative, I reckon, would be to make people aware, rather than to get some valuable statistical data. The project would require some preliminary organization, we would have to agree as to what to exclude, what to allow in the way of additives, and sweeteners. For I think, it would be worthless to exclude only sucrose (table sugar) and allow any problematic sweeteners like saccharine or as-partame. So we would have to draw up a short list of natural sweeteners that would be allowed, like honey or maple syrup… With the additives it would be even much knottier, for regulations and food labelling rules differ from country to country… Anyway, I think it would be worth trying.

Megaera said...

Slowfit/Porcupine -- you really need to take the bad with the good to get reliable information: I actually went gluten free starting 1 Jan. as a coincidence, knowing nothing about this blog, and have continued the experiment through March; I offered to report for Stephen, but he considered it was too late and therefore unacceptable. As it happens, I had no good results to report, only poor or negative ones: no weight loss at all, no beneficial changes in other inflammation-related symptoms, and in fact some actually worsened. I may have gotten the sticky end of the lollipop physiologically speaking, but I suspect that there are more of me out there than researchers like Stephen and fat doctors are willing to acknowledge, because we don't fit their theories and paradigms, and no matter how faithfully we follow their diktats of the moment, nothing good ever comes of it. And we tend to mess up their survey data something fierce.

majkinetor said...

Might-o'chondri-AL said:
"Go off cereal grain and the liver will downshift xanthine oxido-redutase"

I think that coffee or cocoa drinks while off cereals prevents that downshift as XOD is use to metabolise it:

Effect of caffeine on xanthine oxidase activity

Stephan Guyenet said...

Hi Megaera,

I don't appreciate your suggestion that I'm ignoring people who don't do well on gluten restriction. I very explicitly encouraged people who had positive, neutral AND negative experiences to complete the survey, and I made a particular effort to get people with neutral or unfavorable results to respond. You can go back and read my posts if you doubt that. I made every effort to get a maximum % survey response so that the data wouldn't be biased toward positive responses, even organizing a raffle.

Yet despite that, there were very few negative experiences reported, and an avalanche of positive experiences. There were a few people who had a worsening of specific symptoms after the diet change, and I'm making no effort to hide that. It probably has to do with dietary changes that were independent of gluten (eg, carb or fiber restriction), as no one has yet identified any essential or even beneficial substance in gluten that can not be easily obtained elsewhere.

So how about you stop projecting your negative experience on others? If you feel better eating gluten, then just eat it. Many people benefited from the intervention, and you need to accept that.

Unknown said...

I am one of the people who participated in the G-F January and the survey. I have new data I wanted to share.

I decided to participate in the G-F January in sympathy with my daughter who had been complaining of stomach aches a lot. I wasn't expecting anything for myself but was hoping it would help her. It did.

For myself, I felt much clearer in thought so decided to continue with G-F. I have been strictly gluten free since January 1, 2011. A little data from late 2010: one blood test in November 2010 showed my hsCRP at > 50. This was repeated in December 2010 at also > 50. When hsCRP > 10, this usually means some sort of systemic inflammation as opposed to some heart health indicator. My doctor ordered additional tests to try to determine the cause of excess inflammation. The blood draw for the series of tests was taken early April 2011. My hsCRP in April was 0.9.

I have not tried adding gluten back to my diet to see if I can get my hsCRP back up. While it would be the scientific thing to do, I like the way I feel now.

Thanks so much for supporting the G-F January effort.

Stephan Guyenet said...

Hi Cindy,


tootsie said...

Stephan, for those in the study who felt worse after going gluten free, could this possibly have to do with the addictive nature of gluten? Maybe the worsening of symptoms was an effect of withdrawal.
Also, through personal experience, sometimes going gluten-free isn't enough to improve symptoms. I also had to cut dairy (though I've been able to add back butter) and ALL grains as I was still experiencing a lot of GI distress.
I would be really interested in seeing what would happen if you took the same participants who went gluten-free, and moved them to full Paleo.