Gluten-free diets have exploded in popularity in recent years, but many have questioned whether this new food trend is actually medically helpful for those without a diagnosed celiac disease. A new study released by the American Heart Foundation points to a possible relationship between low-gluten diets and a higher risk of Type 2 diabetes.

A Consumer Reports National Research Centre survey from 2014 revealed that up to a third of American adults polled were trying to cut gluten out of their diets. Yet the prevalence of celiac disease in the United States has been relatively stable at about 1 percent of the population. So many people seem to believe that reducing or eliminating gluten from their diet is an inherently healthy act, but is there actually any science to back up that belief?

Researchers at Harvard University set out to determine what health effects avoiding gluten had on those people with no specific medical reason to avoid the substance. They accumulated data previously recorded from three separate long-term health studies comprising nearly 200,000 participants.

The separate studies involved participants logging their food habits in questionnaires completed every two to four years. The Harvard team estimated the daily gluten intake from this data and found that those who ate the most gluten had a lower risk of developing Type 2 diabetes during the 30 years of follow-up.

Drilling more deeply into the dietary habits of the participants it was found that those who ate less gluten also generally consumed less cereal fiber, which is known to reduce the risk of Type 2 diabetes.

"Gluten-free foods often have less dietary fiber and other micronutrients, making them less nutritious," explains Dr Geng Zong, lead author on the study.

The researchers added several caveats to their findings, noting that this was an observational study where participants were reporting their food habits themselves, and there was no data from completely gluten-free diets available as the information was gathered before those food trends became widespread.

So while this is not at all a definitive study, it does certainly build on a body of work in recent years that suggests gluten-free diets are not entirely healthy choices without direct underlying medical reasons.

A study in 2009 from Spain found that a month on a gluten-free diet was enough to significantly diminish the populations of beneficial gut bacteria in participants, while another study found that gluten actually increased the immune response of their test group.

What is clear moving forward is that gluten is probably not the big bad specter of our times. While scientists are still researching the positive health effects of gluten, and it is clear the 1 percent of people with celiac disease should avoid it, for most of us it appears a gluten-free diet is an unnecessary fad that offers no provable health benefits.