For those diagnosed with the autoimmune disorder coeliac disease, avoiding wheat and some other grains is essential.
But now a study examining the eating habits of more than 1000 Australians shows that up to 1 in 10 adults are cutting wheat from their diets without conventional medical advice.
More than half of these so-called 'wheat avoiders' blame nasty post-meal aftereffects for their decision.
"The respondents to our survey link eating wheat with symptoms such as bloating or wind, stomach discomfort or cramps, and feeling sluggish or tired," explained Dr Sinead Golley, lead author on the paper and Research Fellow at the CSIRO Food and Nutrition Flagship based at SAHMRI.
"They avoid wheat-based foods in an attempt to control their symptoms, but they are mostly doing it without any formal medical diagnosis that might indicate an intolerance or allergy."
The results are a concern for Dr Golley and her colleagues, who believe that the decision to self-diagnose and control symptoms by avoiding wheat could have health consequences.
"Wholegrain cereals make a positive contribution to health by supplying a range of nutrients including protein, fibre and other carbohydrates, vitamins and minerals," said Dr Golley.
"By avoiding wheat, people may be missing out on very important nutrients."
"In addition, in bypassing medical advice through self-diagnosing they are potentially at risk of a serious clinical condition going undetected," she said.
Irritable bowel syndrome could be the cause of abdominal pain and altered bowel habits in some individuals.
It could also be the case that wheat is taking the rap when other dietary components are actually to blame.
"Although we didn't examine it in this study, a possible contributor to the abdominal symptoms in some of these people could be simple sugars, such as fructans and lactose, which are present in many foods, including bread products," said Dr Golley.
Fructans and lactose fall into a group of carbohydrate molecules known as FODMAPs (Fermentable Oligosaccharides Disasaccharides Monosaccharides Polyols). Maladsorption of FODMAPs is believed to contribute to some symptoms of irritable bowel syndrome.
So why do so many people avoid the doctor when it comes to dietary issues?
It's a matter of trust.
"Food intolerances are particularly hard to diagnose with certainty, so mainstream medicine may not always have the definitive answers that these people may be looking for," said Dr Golley.
"There is a great deal of information to be found outside medical sources attributing ill-effects to the consumption of certain foods. These sources can include complementary medicine, family and friends and the media."
The research found that wheat avoidance was more common in females, and in those with a lowered receptiveness to conventional medicine and a greater receptiveness to complementary medicine.
More than 50% of wheat avoiders were also found to avoid dairy foods.
The study was published in Public Health Nutrition, and also featured in Medical Journal of Australia.