Researchers trying to figure out how meat causes heart disease came up with another possible explanation Monday: an essential nutrient found in meat and eggs might be a culprit. They found evidence that choline may feed gut bacteria that in turn produce a compound that makes blood sticky and prone to form clots that can cause heart attacks and strokes. A photo of eggs cooked to different temperatures included in "The Food Lab" by J. Kenji López-Alt. J. Kenji López-Alt / W.W. Norton and Company It’s the latest in their series of studies looking at what specific compounds in food raise people’s risk of heart disease, the no. 1 cause of death in the U.S. and much of the world. Choline is considered an essential nutrient and getting too little can, ironically, lead to heart disease, cancer and other conditions. It’s found in abundant quantities in egg yolks, liver, red meat, peanuts and wheat germ. Dr. Stanley Hazen of the Cleveland Clinic and colleagues did a small but intense study in 18 volunteers – eight of them vegetarians or vegans, and 10 people who eat meat, eggs and dairy. They gave all 18 choline supplements – 500 mg daily. The recommended adequate intake of choline from all sources is 425 mg a day for women and 550 mg a day for men. “Unless prescribed by your doctor, avoid supplements with choline.” After a month, their blood levels of a compound called trimethylamine N-oxide (TMAO) rose 10-fold. In tests, their blood became much more likely to form clots, the team reported in the journal Circulation. "TMAO supercharges platelet function," Hazen said. Platelets are are cell-like structures in the blood that help form blood clots. TMAO makes them sticky, Hazen said. "What is clear from this study is if you increase the choline in your diet, the TMAO level goes up and that changes your platelet function," Hazen told NBC News. The vegans and vegetarians had much lower levels of choline to start with than the meat-eaters did, Hazen’s team reported. Even after taking choline, their blood levels were much lower. “Foods that raise TMAO may increase your risk for clotting and thrombotic events. Unless prescribed by your doctor, avoid supplements with choline,”