Meat vs. Veggie Amino Acids

Recent research has led scientists to conclude that an elevated level of an amino acid called homocysteine in the blood is a central risk factor associated with Alzheimer’s disease. Amino acids are a fundamental part of the human diet. In various combinations, the 20 biologically important amino acids work together to form countless proteins, in much the same way that the 26 letters of the alphabet can form millions of words. While half of these amino acids can be manufactured by the human body, the other 10 “essential” amino acids must come from the foods we eat. But too much of some of these amino acids can be dangerous.

The amino acids methionine and homocysteine have both been proved to be hazardous to human health in high doses. Methionine is found in many of the foods that Americans eat, but animal proteins can contain up to two to three times more methionine than plant proteins. Homocysteine is formed naturally in the human liver after ingesting methionine. Recently, investigators at Boston University found that elevated levels of homocysteine are associated with an increased risk of developing Alzheimer’s disease. This may be because of the fact that high homocysteine levels make nerve cells weak and prone to premature death.

Since animal proteins contain greater amounts of methionine than plant proteins, eating meat can raise homocysteine levels and increase the risk of developing Alzheimer’s disease. Dairy products, particularly cheese products, also contain high levels of methionine. Consequently, eating meat or consuming dairy products creates a methionine-rich and, consequently, homocysteine-rich environment, dramatically increasing the risk of developing Alzheimer’s disease.



Studies show that people who have adopted a vegan diet (free of meat, eggs, and dairy products) can lower their homocysteine levels by as much as 20 percent in one week. This may be because of the effects of folic acid, a B vitamin found in whole grains, green vegetables, beans, and many other plant-based foods, which helps to convert homocysteine to another, more useful amino acid. The American Heart Association confirms that “[f]resh fruits and vegetables … are the best line of defense against raised homocysteine levels.”

Read more.