Move over saturated fat and cholesterol; there are two new health culprits in town that are linked to raising heart disease risk. Last month, news circulated widely about one of these culprits when research revealed how consumption of l-carnitine, found abundantly in red meat as well as in dairy, fish and chicken, plays a significant role in the development of heart disease.
In addition, just last week, a new study revealed that through a similar process, lecithin, found in eggs, also raises heart disease risk.
The process starts in the gut. When an individual’s gut bacteria metabolize l-carnitine, a substance called TMAO is released into the bloodstream by the liver. High TMAO in the blood promotes atherosclerosis, a thickening of the arteries, and has been linked to an increased risk for heart attack and stroke. To further study the link between TMAO and heart disease, researchers looked at 4,000 people who were being seen at the Cleveland Clinic. Of the participants, the top 25 percent of people with the highest TMAO levels in their blood had a 2.5 times higher risk of having a heart attack or stroke than participants in the lowest 25 percent.
Researchers already knew that l-carnitine has a similar structure to choline, a product produced in the body with the chemical breakdown of lecithin (found in eggs.) This led researchers to suspect that high lecithin intake from eggs would also result in high levels of TMAO in the body. According to research that took blood samples from participants before and after eggs were consumed, even eating just two hard-boiled eggs increased participants’ blood levels of TMAO.
In addition to heart disease risk, choline intake and prostate cancer risk has also been studied. In a NutritionFacts.org video (featured below), Dr. Michael Greger summarizes studies that make this connection. In one of the studies, men who ate even less than a single egg a day had a significant 2 fold increased risk of prostate cancer progression. Another study found that men who ate 2 1/2 or more eggs per week had an 81% increased risk of lethal prostate cancer compared to those who consumed less than one half an egg per week. It’s suspected that choline plays a large role in why eggs are so dangerous for prostate cancer patients. In fact, the video shows that choline is so concentrated in cancer cells that if you follow choline uptake in the body, you can track the spread of cancer through the body.
These results reinforce existing health recommendations to reduce meat, eggs, and dairy consumption to improve health and lower risk of chronic diseases.
One such recommendation is from the Harvard School of Public Health which states on their website, “Eating a plant-based diet is healthiest. Make half your plate vegetables and fruits. Cook with healthy plant oils, like olive and canola oil. Get most or all of your protein from beans, nuts and seeds, or tofu.”