Gluten intake does not induce coronary heart disease
It appears that long-term dietary consumption of foods containing gluten does not increase the risk of coronary heart disease (CHD), suggests a recent study. However, the avoidance of gluten may result in a reduced intake of beneficial whole grains, which may affect cardiovascular risk.
“[W]e found no significant association between estimated gluten intake and the risk of subsequent overall coronary heart disease, nonfatal myocardial infarction and fatal myocardial infarction,” researchers said. “The lack of association was consistent in both men and women, as well among other subgroups defined by cardiovascular risk factors.”
In this prospective cohort study, researchers examined the association between gluten intake and the development of incident CHD. Included were 64,714 women in the Nurses’ Health Study and 45,303 men in the Health Professionals Follow-up Study without a history of coronary heart disease who completed a 131-item semiquantitative food frequency questionnaire in 1986 that was updated every 4 years through 2010.
A total of 2,431 women and 4,098 men developed CHD during 26 years of follow-up encompassing 2,273,931 person-years. Participants in the highest fifth of gluten intake had a CHD incidence rate of 277 events vs 352 per 100,000 person years in the lowest fifth, leading to an unadjusted rate difference of 75 (95 percent CI, 51 to 98) fewer cases of CHD per 100,000 person-years. [BMJ 2017;357:j1892]
After adjustment for known risk factors, participants in the highest fifth of estimated gluten intake had a multivariate hazard ratio [HR] for CHD of 0.95 (0.88 to 1.02; p=0.29 for trend). The multivariate HR after additional adjustment for consumption of whole grains (leaving the remaining variance of gluten corresponding to refined grains) was 1.00 (0.92 to 1.09; p=0.77 for trend).
“Whole grain intake has been found to be inversely associated with coronary heart disease risk and cardiovascular mortality,” researchers noted. [BMJ 2016;357:i2716; JAMA Intern Med 2015;357:373-84]
On the other hand, additional adjustment for consumption of refined grains (leaving the variance of gluten intake correlating with whole grain intake) showed that estimated gluten consumption was associated with a lower risk of CHD (multivariate HR, 0.85; 0.77 to 0.93; p=0.002 for trend).
“Although people with and without coeliac disease may avoid gluten owing to a symptomatic response to this dietary protein, these findings do not support the promotion of a gluten restricted diet with a goal of reducing coronary heart disease risk,” researchers said.
“Patients with coeliac disease who develop a myocardial infarction are less likely to have classic cardiac risk factors, such as smoking and dyslipidemia, leading to the hypothesis that the proinflammatory effect of gluten exerts an independent cardiac risk,” they added. [Aliment Pharmacol Ther 2013;357:905-14]
Gluten is a storage protein in wheat, rye and barley that can trigger inflammation and intestinal damage in people with coeliac disease. [BMJ 2015;357:h4347]