New Delhi, July 24 (ANI): People who follow paleo diet were found to have twice the amount of a key blood biomarker that is linked closely to heart diseases, suggests a study. The study published in the 'European Journal of Nutrition' examined the impact of the diet on gut bacteria. Researchers compared 44 people on the diet with 47 following a traditional Australian diet. They measured the amount of trimethylamine-n-oxide (TMAO) in participants' blood. High levels of TMAO, an organic compound produced in the gut, are associated with an increased risk of heart disease. The controversial Paleo (or 'caveman') diet advocates eating meat, vegetables, nuts and limited fruit, and excludes grains, legumes, dairy, salt, refined sugar and processed oils. Dr Angela Genoni, the lead researcher said that with the diet's growing popularity, it was important to understand the impact it could have on overall health. She said the reason TMAO was so elevated in people on the Paleo diet appeared to be the lack of whole grains in their diet. The researchers also found higher concentrations of the bacteria that produce TMAO in the Paleo group.