Friday, May 5, 2017

Fake News Warning: Gluten Free Diet

The last few days we have seen a flurry of FAKE NEWS headlines about gluten free diets.

FOX News: A gluten-free diet may raise your risk of heart disease
GLOBAL: Going gluten-free to ward off heart disease might have opposite effect: study
CBC: Healthy hearts: Gluten-free diets don't help people without celiac disease, study finds
MedicalNews.Net: Study finds no link between gluten intake and heart disease risk in people without celiac disease
Irish Mirror: Eating a gluten free diet when you're not coeliac could damage your health
NEJM: (email teaser) Low-Gluten Diet Not Tied to Lower Coronary Risk. (article header) Gluten-Restricted Diets Seem Not to Lower Coronary Risk

Are these reports fake news?  Yes, every one of them.  Let's check the facts.
 All of the above reports, published on May 2 or May 3, 2017 refer to the same research study published in the BMJ. According to Wiki, "The BMJ is a weekly peer-reviewed medical journal. It is one of the world's oldest general medical journals. " The study comes with the tedious title: "Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study".

Incidentally, the study, published in the BMJ is free. You can click the link above, and read it yourself. Perhaps this, in itself, should be a warning that maybe some propaganda is being delivered? If you want to read the study "Celiac disease and non-celiac gluten sensitivity" on the BMJ, it will cost you $37.  If you want to read "Gluten sensitivity: a many headed hydra", same same, $37.  Why is the latest research study 'free'? Does the BMJ believe this study is so important that it should be freely available?

Let's take a look at the actual study, and the actual conclusions of the study. Then we can compare the study, and the study results, to the above 'news' reports to find the 'fake news'.

Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study: 

Objective To examine the association of long term intake of gluten with the development of incident coronary heart disease. NOTE: The objective was NOT to examine gluten free diets, and gluten free diets were not studied. 

Participants:  (none actually).  The study was research into data held in the Nurses’ Health Study and the Health Professionals Follow-up Study collected between 1986 and 2010.

Note: The title of the study is incorrect - should we call it 'fake news'?  The title of the study says "in adults without celiac disease", but the participants data did not contain any information about celiac disease prior to 2014.  The study data could not distinguish between participants with celiac disease, and participants without celiac disease - because the data was not collected. The people who reported celiac disease - in 2014 or later, were eliminated from the study - leaving only people of unknown status. There was no study of "adults without celiac disease".

Exposure to Gluten: Consumption of gluten, estimated from food frequency questionnaires. Intentional gluten avoidance was not measured. Gluten free diets were not studied. 

Main outcome measure Development of coronary heart disease (fatal or non-fatal myocardial infarction). Heart healthiness was not measured, only the incidence of serious heart failure.

Conclusion Long term dietary intake of gluten was not associated with risk of coronary heart disease. Not associated? But.. but... the news reports seem to say that gluten free diets are associated with heart disease? Seriously? What's going on?

The Fake News

The study did not end with the 'conclusion'.  It ended with a couple of extra waffling sentences, added on to the end of the conclusion: "However, the avoidance of gluten may result in reduced consumption of beneficial whole grains, which may affect cardiovascular risk. The promotion of gluten-free diets among people without celiac disease should not be encouraged."

These sentences appear at the bottom of the study. You might think - if you don't read carefully, that these sentences are supported by the study. If you read the study carefully, you will find that AFTER the conclusion was found, after it was learned that "Long term dietary intake of gluten was not associated with risk of coronary heart disease", the researchers took an extra step, which they describe as follows:

"After adjustment for known risk factors, participants in the highest fifth of estimated gluten intake had a multivariable hazard ratio for coronary heart disease of 0.95 (95% confidence interval 0.88 to 1.02; P for trend=0.29). After additional adjustment for intake of whole grains (leaving the remaining variance of gluten corresponding to refined grains), the multivariate hazard ratio was 1.00 (0.92 to 1.09; P for trend=0.77). In contrast, after additional adjustment for intake of refined grains (leaving the variance of gluten intake correlating with whole grain intake), estimated gluten consumption was associated with a lower risk of coronary heart disease (multivariate hazard ratio 0.85, 0.77 to 0.93; P for trend=0.002)."

Seriously?  I challenge any news writer, from the above news articles, to translate that into the standard English level of their readers (watchers, listeners, as the case may be). I won't try.  I'm not interested.

There is no need to Understand the above paragraph 

The research did not actually study anyone on a 'gluten free diet' except perhaps by accident.

The research did not study any anyone on a gluten free diet - who has been diagnosed as celiac, or not, except perhaps by accident, because that data was not collected.

The suggestion that "promotion of gluten-free diets amoung people without celiac disease should not be encouraged" is opinion, speculation, not supported by the research. It might be supported by complicated analysis of 30 year old data, that does not contain any direct information about gluten free diets, nor about celiac disease - in the data selected for the study.

The statement that "However, the avoidance of gluten may result in reduced consumption of beneficial whole grains, which may affect cardiovascular risk." is a hypothesis, not a conclusion.  It is, perhaps, a basis for a new research study.  One that actually studies people on a gluten free diet, people diagnosed with celiac disease, and compares them to people on a gluten free diet who have not been diagnosed with celiac disease.  This study has not been done.

However, if you read the fake news reports, you could easily believe that it has been done and the results are in, and the results are bad.

That's fake news.

If you are a news reporter looking for a story, you need to read fast.  If you read quickly, and don't notice the weasel words 'however..." followed by "may result...", followed by "may affect..." you might easily think that the study says:

FOX News: A gluten-free diet may raise your risk of heart disease
GLOBAL: Going gluten-free to ward off heart disease might have opposite effect: study
CBC: Healthy hearts: Gluten-free diets don't help people without celiac disease, study finds
MedicalNews.Net: Study finds no link between gluten intake and heart disease risk in people without celiac disease
Irish Mirror: Eating a gluten free diet when you're not coeliac could damage your health
NEJM: (email teaser) Low-Gluten Diet Not Tied to Lower Coronary Risk. (article header) Gluten-Restricted Diets Seem Not to Lower Coronary Risk

It doesn't.  Every one of the reports on FOX, Global, CBC, MedicalNews.net, the Irish Mirror - and I am certain many more - are based on a hypothesis published in the BMJ - that was not actually studied, and therefore not supported by the study quoted in the news reports. Apparently, fake news breeds more fake news. Are we surprised?

We've seen the fake news.  Maybe it's time to look at the real news? Here's the real news.

1. A group of researchers studied gluten consumption and medical data in the Nurse's Health Study, from a time period before celiac disease data was collected. They published a report concluding that "Long term dietary intake of gluten was not associated with risk of coronary heart disease". Participants who reported celiac disease (reported after 2014) were eliminated from the study.

2. At the end of the report, the researchers published a hypothesis that however, maybe, maybe, a gluten free diet in people who are NOT diagnosed as celiac, could increase risk of heart disease. However no gluten free diets were studied.

3. The researchers did not study any people with celiac disease.  They did not study anyone without celiac disease.  They deliberately eliminated people who were known to have celiac disease from the study.  Who is left?  People whose status is unknown. There is no evidence, other than statistical evidence, that any individual in the study does not have celiac disease.

4. There was no attempt to measure the healthiness effects, positive or negative, related to consuming more or less gluten.  The study focused attention on a specific set of diseases and ignored all other consequences.

When we learn to study health, we will come closer to finding real news.  Until then, fake news rules!

to your health, tracy