Red meat is, of course, a rich source of protein, but questions about its contribution to heart disease and other ailments have many people wondering if they should reduce their consumption or even strike red meat from their diets altogether.
Here, we'll take a look at the nutrient choline and the compound carnitine, which plays a role in energy production in the human body, and their relationship to red meat.
What is choline?
Choline is a nutrient that plays a role in liver function, normal brain development, muscle movement, nerve function, metabolism, and sleep. Choline is also involved in absorbing and removing fat and cholesterol from the body, reducing chronic inflammation, and the kidneys control of water balance.
What is carnitine?
Carnitine is an umbrella term for several amino acid compounds. Amino acids are the building-blocks of protein and, as stated above, carnitine plays a role in energy production — namely, by moving long chain fatty acids along a series of events that happen in the body so they produce energy. Carnitine levels are highest in skeletal and cardiac muscles which utilize fats for fuel.
Dietary sources of choline and carnitine
The body makes carnitine, so dietary and supplemental carnitine is not necessary in most cases. Carnitine is produced from the biosynthesis of the amino acids methionine and lysine, which are found in beans, rice and a number of other vegetables. These amino acids can also be found in eggs and dairy, as well as legume foods such as tofu. Carnitine once synthesized is often added to energy drinks and may also be taken as a supplement.
Choline is found in eggs, milk, poultry, shellfish, fish, and red meat.
Oxidation of carnitine and choline leading to increased heart attack risk
The reason for concern regarding carnitine and choline (and, consequently, red meat) is due to the oxidation of these two nutrients.
During digestion gut bacteria metabolize carnitine to trimethylamine. Trimethylamine is further oxidized in the liver to trimethylamine-N-oxide (TMAO). TMAO is then released into the bloodstream.
The body also can convert choline into TMAO.
Trimethylamine-N-oxide is a substance that appears to increase cholesterol buildup and plaque formation in arteries, which leads to increased risk for heart attacks and strokes.
After consuming carnitine, meat eaters produce more TMAO versus those who consume a mostly plant-based diet.
Research continues on this confusing subject, but it has been shown that carnitine and choline by themselves are not the culprits for TMAO production. If you consume a diet high in meat, gut bacteria may be altered, resulting in increased production of TMAO, which is one way a diet high in red meats may increase heart disease risk.
The takeaway here? All things in moderation. Keep variety in your diet. Don’t eat red meats daily: mix it up with poultry, fish, and vegetarian meals. A well-balanced diet equals healthy gut flora, which means reduced risk for production of TMAO and other harmful byproducts of digestion.
While the DASH Diet is aimed at lowering blood pressure, it is a great, well-balanced diet for anyone with heart-health concerns.