Homocysteine is what scientists refer to as a non-protein amino acid. In other words, we cannot build protein from homocysteine. It is a substance found in the blood that can be accurately measured with a simple blood test. Homocysteine is not obtained from the diet but is biosynthesized inside our bodies from the amino acid methionine by the removal of a methyl group.
In 1968 a Harvard researcher discovered that children with elevated homocysteine levels due to a genetic defect had vascular disease similar to middle-aged people with the disease. This groundbreaking discovery concluded that excess homocysteine could be a risk factor for heart disease.
It is now known that elevated homocysteine can lead to inflammation of the thin layer of cells that line the interior surface of blood vessels, called the endothelium. If the elevated level of homocysteine is not lowered, it may lead to inflammation of the arteries, veins, and capillaries which carry blood to all parts of the body. After that happens, artery walls may begin to thicken from the accumulation of calcium and fatty materials. This is known as atherosclerosis. This in turn can result in the restriction of blood supply to tissues, causing a shortage of oxygen and glucose which is needed for cellular metabolism.
Elevated levels of homocysteine have been correlated with the occurrence of blood clots, heart attacks, and strokes. However, many cardiologists are still not checking homocysteine levels in their patients unless the person specifically asks to be checked. This may be due in part to the fact that testing homocysteine levels is not usually covered by health insurance and that there is no pharmaceutical treatment for elevated homocysteine levels other than natural vitamin supplementation along with a diet high in raw leafy green vegetables.
Blood levels of homocysteine are statistically higher in people who eat a lot of animal protein and don’t consume adequate amounts of fruits and leafy green vegetables. Research also indicates the more coffee one drinks, the higher the homocysteine level becomes. Reducing the consumption of animal protein and coffee can help lower homocysteine levels. The literature shows that levels tend to be higher in men than in women and increase with age.
Stress has been linked to elevation as well. The neurotransmitters epinephrine and norepinephrine are elevated by stress and need to be metabolized in the liver with a process that uses methylated B vitamins. When we use up these methyl groups, we can’t process homocysteine and the level rises in the bloodstream.
There are numerous unhealthy effects that homocysteine can have on the human body in addition to damaging the circulatory system. Some such health conditions include: macular degeneration, spontaneous abortion, migraine headaches, congestive heart failure, hearing loss, high risk of Alzheimer's disease, and many more conditions.
The good news is that homocysteine can be recycled back into methionine or converted into cysteine with the aid of B-vitamins; more specifically, folate (active folate is known as methyltetrahydrofolate), vitamin B6, and the methylated form of vitamin B12 called methylcobalamin. Note that I said folate and not folic acid, also methylcobalamin and not cyanocobalamin. Folic acid and cyancobalamin are synthetic.
It is now known that approximately one out of every five people have some level of a genetic mutation that makes it difficult to convert synthetic B vitamins into usable ones. It is known as the MTHFR-677 mutation. People with this mutation have been found to have high levels of homocysteine when they are not consuming adequate amounts of food derived B vitamins. This is because they have a limited ability to add a methyl group to synthetic vitamins to make them useable. (For more information on the MTHFR mutation, see my article and video on it.)
There are two commonly known ways that homocysteine is converted into usable substances. One requires folate and vitamin B12. This path turns homocysteine back into methionine. The other requires vitamin B6 as a co-factor (pyridoxal phosphate is the active form of vitamin B6). This route converts homocysteine into cysteine, which is then used by the body to make glutathione, a powerful antioxidant very useful in the body.
Other substances have also been shown to lower homocysteine levels in the human body. Betaine hydrochloride (betaine HCL) can be purchased as a dietary supplement or can be obtained from eating or juicing beets. Betaine turns homocysteine into cysteine. N-acetyl-cysteine (NAC) can also reduce blood plasma homocysteine levels and improve endothelial function. Furthermore, research indicates that vitamin B2 (riboflavin) and magnesium are involved in homocysteine metabolism.
I recommend that everyone check their homocysteine levels once every few years as they age and especially if they are less than optimally healthy. I also believe that everyone should carefully follow their nutritional status with annual testing from a reputable lab that does intra-cellular testing. And lastly, consume a healthy diet with lots of fresh vegetables and a great multi-vitamin that contains food extracted vitamins.
Craig B. Sommers, ND, CN