9. Heart risk through the gut
In 2013, researchers added a new biomarker to the hunt for heart disease: TMAO. Your body produces TMAO (trimethylamine N-oxide) when your gut bacteria digest choline, which is found in egg yolks, red meat and dairy products. Choline is thought to promote hardening of the arteries. TMAO provides an accurate screening tool for predicting future risks of heart attack, stroke and death.