Gluten-Free Diet Does Not Protect Against Heart Disease in Those Without Celiac Disease

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gluten-free diet

There is a rising trend in adopting a gluten-free diet, whether or not one has gluten intolerance. This is based on the perception that gluten consumption carries adverse health effects, such as an increased risk of developing heart disease. A long-term prospective study reports that gluten consumption is not associated with detrimental cardiovascular outcomes, and cautions against the widespread adoption of gluten-free diet in people without gluten intolerance.

For those with gluten sensitivity, its consumption can trigger an autoimmune attack on, and subsequent damage of, the intestinal villi cells. This may manifest in a plethora of symptoms such as abdominal pain, bloating, diarrhea or even constipation.

Also known as celiac disease, this defective immune response is associated with an increased risk for cardiac disease. In other words, gluten consumption in gluten-sensitive population can increase the risk of adverse cardiovascular events. On the other hand, even in the absence of celiac disease, gluten consumption has been proposed to promote inflammation. Such assumptions are based on limited, and often controversial evidence. Nonetheless, diets that limit gluten intake have gained widespread popularity. For example, in a recent follow-up of the National Health and Nutrition Examination Survey (NHANES), adoption of a limited gluten diet by people without celiac disease increased more than threefold from 2009-10 to 2013-14.

In a study published in The BMJ, researchers at Columbia University in New York, NY, and Harvard Medical School in Boston, MA, examined the association between long-term gluten intake and the incidence of coronary heart disease. The prospective cohort study involved 64,714 women from the Nurse’s Health Study and 45,303 men from the Health Professionals Follow-up Study. Beginning in 1986, and continuing until 2010, participants were regularly asked to complete a 136 item semi-quantitative food frequency questionnaire, with diet being assessed every four years. This helped estimate the quantity of gluten being consumed over the long-term. Cohort participants were then divided into fifths of estimated gluten consumption. The primary outcome of cardiac disease included the diagnosis of non-fatal or fatal myocardial infarction. The association between the two was then tested by comparing adverse cardiac events in each range of gluten intake and comparing it to the group with the lowest consumption.

During the 26 years of follow-up, those with the highest gluten intake had 75 fewer cases of cardiac disease per 100,000 person-years compared with participants in the lowest fifth of gluten intake. Even after adjusting for other variables, the study found no association between the estimated intake of gluten and incidence of heart disease. The lack of association was consistent between men and women, as well as other subgroups defined by cardiovascular risk factors.

The study cautions against the widespread adoption of gluten-free/restricted diets in the absence of celiac disease. Such diets are not only nutritionally suboptimal, as they decrease the overall consumption of whole grains, but also costly as gluten-free substitute food tends to be more expensive. Furthermore, the consumption of whole grains has been found to be inversely correlated with coronary heart disease. Hence, by limiting them in our daily diet, one might actually increase the risk of developing cardiovascular disorders in the long-term.

Written By: Debapriya Dutta, PhD

http://www.bmj.com/content/357/bmj.j1892 Benjamin Lebwohl et. al.