Researchers at Harvard University have found a link between the consumption of gluten and a lower risk of type 2 diabetes.

Dieticians say Australians must not be fooled into thinking a gluten-free diet is healthier, with a Harvard University study linking consumption of the much-maligned protein to a lower risk of Type 2 diabetes.

A longitudinal study of more than 200,000 Americans over 30 years found those who consumed a normal amount of gluten had a 13 per cent lower risk of developing the metabolic disorder, compared to those who consumed less than four grams a day.

Those who ate low levels of gluten also tended to eat less cereal fibre, known to protect people against Type 2 diabetes.

"Gluten-free foods often have less dietary fibre and other micronutrients, making them less nutritious and they also tend to cost more," said lead researcher Geng Zong from the Department of Nutrition at Harvard University.

People without Coeliac disease may want to reconsider limiting their gluten intake in order to prevent disease, Dr Zong said.

Gluten is a protein found in wheat, rye and barley.

A small percentage of the population can't tolerate gluten because of Coeliac disease or gluten sensitivity, but gluten-free diets have become popular for people without these conditions.

Dr Zong and his colleagues examined the daily intake for nearly 200,000 people who participated in three health studies from 1984-1990, to find out how consumption affected the health of people with no medical reasons to avoid gluten.

On average, the daily gluten intake was 6.5 grams and the major sources of gluten came through the consumption of pastas and cereals.

On follow-up nearly 16,000 cases of Type 2 diabetes were confirmed between 2010-2013.

The research was presented at the American Heart Association's Epidemiology and Prevention/Lifestyle and Cardiometabolic Health 2017 Scientific Sessions.

Melanie McGrice, an accredited practising dietitian and spokesperson for the Dietitians Association of Australia said the research makes a lot of sense.

"We have recognised for years that with our clients who have Coeliac disease that there is a corresponding very high rate of type 2 diabetes," Ms McGrice told AAP.

She says it is quite common for dietitians to have the "difficult" task of having to work out meal plans for those with both coeliac disease and diabetes.

Whether it's the gluten that actually makes the difference, or whether its the type of gluten-free foods people are eating, remains unknown, Ms McGrice added.

However, she believes perception that gluten-free foods are healthier needs to change.

"They are often higher in kilojoules and more refined," she said.

"If you need to follow a gluten-free diet for health reasons then those diets are in place for very important reasons. But if you don't need to then don't be fooled that it's a healthier option."