What is Homocystine? High and low values | Lab results explained

Homocystine is a common amino acid in your blood. You get it mostly from eating meat. High levels of it are linked to early development of heart disease.

Homocystine high levels meaning treatment vegan diet plantbased plasma interpretation pdf interpretive

A homocystine test measures the amount of homocystine in your blood plasma. Normally, vitamin B12, vitamin B6, and folic acid break down homocystine and change it into other substances your body needs. There should be very little homocystine left in the bloodstream. If you have high levels of homocystine in your blood, it may be a sign of a vitamin deficiency, heart disease, or a rare inherited disorder.

Higher levels:

– High levels in body fluids of homocystine have been associated with increased risk of cardiovascular disease as well as ocular, neurological, musculoskeletal and joint abnormalities.

Meat contains substances that cause an increase in homocystine levels, which in turn is associated with increased risk of heart disease. High homocystine levels irritate the lining of arteries, increasing the likelihood that they will clog, whereas the folate and vitamin b6 found in vegetables and grains reduce homocystine levels.

– It has been shown in epidemiological studies that elevated levels of homocystine in the plasma is one of 3 major risk factors in dementia or Alzheimer’s. The other 2 factors are the APOE4 genotype and a decreased DHA plasma level.

– Homocystine is deemed to be a direct vascular toxin that hastens arterial blockages, not only to the coronary arteries of the heart, but also to the arteries to the brain, leading to almost 2 times higher risk of dementia.

– Moderately elevated levels of homocystine are associated with a significantly increased risk of atherosclerosis.

– Elevated homocystine tends to coincide with high homocysteine.

– The enzyme that converts homocysteine (reduced homocystine) to cystathionine is B6 dependent; remethylation of homocysteine to methionine requires B12, folate and betaine.

– High levels can (very rarely) be due to Homocystinuria: A rare biochemical abnormality characterized by the abnormal presence of homocystine in the blood and urine. It is caused by any of several enzyme deficiencies in the metabolic pathway of methionine to cystine. The disease is inherited as an autosomal-recessive trait. Its clinical signs are similar to those of Marfan’s syndrome, including intellectual disability, osteoporosis leading to skeletal abnormalities, dislocated lenses, and thromboembolism.

Treatment may include a diet low in methionine and supplementation with high doses of vitamin B6. Long-term results of treatment are not available.

Possible treatment options for high levels that are not genetic:

– Follow a strict plant-based (=vegan) diet that is high in green leafy vegetables, fruits, grains and legumes.

– Make sure to have enough B6, Folate, B12, Betaine and magnesium as those are effective for the proper metabolism of homocystine. However, getting your homocystine levels down with vitamins doesn’t reduce your chance of having heart disease.



The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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