Australian researchers have found elevated levels of a biomarker linked to heart disease in the blood of people on the Paleo diet, possibly caused by red meat.

Eating more red meat under the Paleo diet paired with a lack of whole grains results in higher levels of a biomarker linked to heart disease, new research suggests.

In the world first study, researchers compared the gut health of 44 people on the Paleo diet with that of 47 people on a traditional Australian diet.

The Paleo diet involves eating meat, vegetables, nuts and limited fruit, while excluding grains, legumes, dairy, salt, refined sugar and processed oils.

Researchers at Perth's Edith Cowan University measured blood levels of trimethylamine-n-oxide (TMAO), an organic compound produced in the gut, and found more than twice the amount in those on the Paleo diet.

High levels of TMAO has been associated with an increased risk of cardiovascular disease.

Head researcher Angela Genoni says the findings question the gut health benefits of the diet.

"The Paleo diet excludes all grains and we know that whole grains are a fantastic source of resistant starch, and many other fermentable fibres which are vital to the health of your gut microbiome," Dr Genoni said.

"Because TMAO is produced in the gut, a lack of whole grains might change the populations of bacteria enough to enable higher production of this compound.

"Additionally, the Paleo diet includes greater servings per day of red meat, which provides the precursor compounds to produce TMAO."

Dr Genoni will present the findings at the Nutrition Society of Australia conference in Canberra on Friday.