Researchers announced in April that they may have figured out how eating meat causes heart disease. The nutrient choline, an essential nutrient found in meat and eggs, may feed a certain gut bacteria which produce a compound that makes blood sticky and prone to form blood clots. These blood clots can lead to heart attacks and strokes. 
The study, led by Dr. Stanley Hazen of the Cleveland Clinic, was a small but intense one involving 18 participants – 8 who were either vegans or vegetarians and 10 who routinely ate meat, dairy, and eggs. Each volunteer was given a supplement of 500 mg of choline per day. The recommended daily choline intake for women is 425 mg, and for men it’s 550 mg.
After a month, the participants’ blood levels of a compound called trimethylamine N-oxide (TMAO) rose 10-fold. Tests showed that their blood became much more likely to form clots, leading the team to surmise that “TMAO supercharges platelet function.” Hazen added:
“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.” 
Both the vegans and the vegetarians had significantly lower choline levels at the beginning of the study than the meat-eaters did. Their levels were still much lower than the meat-eaters’ after taking choline supplements.
The researchers did not find, however, that the volunteers who took the choline supplements had an actual higher risk of heart disease. The study did not last long enough or include enough participants to demonstrate such a conclusion.
But they did discover that other compounds found in animal products had a similar effect on gut bacteria. The team wrote:
“We previously showed gut microbial production of trimethylamine N-oxide (TMAO) from dietary nutrients like choline, lecithin, and L-carnitine is linked to the development of cardiovascular diseases.” 
The scientists also found that taking low-dose aspirin seemed to reduce the stickiness of platelets and also reduced the choline-associated increases in TMAO and platelet clotting, although it didn’t completely eliminate them. The finding is of particular concern for people who are at an elevated risk for cardiovascular problems, whose increased risk of blood clots may not be overcome by low-dose aspirin. 
It also got the researchers to thinking that it might be worthwhile to study whether low-dose aspirin might help otherwise healthy people who have high levels of TMAO in their blood. First things first, though – they need to figure out why aspirin seems to lower TMAO before they can proceed. Besides, aspirin can cause its own slate of health problems.
So, what is the best way to avoid excess, clot-promoting choline? Well, the team isn’t recommending that people stop eating animal products, but they are urging people to avoid choline supplements. Hazen says:
“Foods that raise TMAO may increase your risk for clotting and thrombotic events. Unless prescribed by your doctor, avoid supplements with choline. A Mediterranean or vegetarian diet is reported to help reduce TMAO.” 
Mediterranean diets have a long history of being heart-healthy. There is no specific guide to follow when it comes to the eating pattern, but Mediterranean diets are rich in fruit, vegetables, beans, nuts, legumes, lean cuts of poultry and fish, and olive oil. Little to no red meat is included in the diet.
Previous studies have shown that olive oil consumption lowers the risk of heart disease. One study even showed that a Mediterranean diet may be more beneficial to people with high cholesterol than statin drugs.
 NBC News
 Business Journal