Homocysteine is an amino acid that the body produces. Abnormal homocysteine levels may indicate that a person has a deficiency in specific vitamins or a higher chance of developing certain medical conditions.

Most people have low homocysteine levels because the body breaks down the amino acid into usable compounds.

High or elevated homocysteine levels could indicate a person has a vitamin deficiency or has an increased risk factor for cardiovascular disease and several other conditions.

In rare cases, homocysteine could be due to homocystinuria, which is a genetic disease that doctors may test for in a newborn.

Homocystinuria means that the body is not able to process amino acids properly.

a man feeling dizzy because of high homocysteine levelsShare on Pinterest
A person with high homocysteine levels may experience weakness, dizziness, and fatigue.

According to an older article, normal and abnormal levels of homocysteine can vary between people. However, typically, if a person’s homocysteine levels are less than 13 micromoles/liter (μmol/L), healthcare providers consider them normal.

They also consider homocysteine levels measuring between 13–60 μmol/L as moderately high, and levels between 60–100 μmol/L as severely elevated.

According to a recent review of studies published in the journal Nutrition and Metabolism, the presence of high levels of homocysteine may indicate a higher risk factor for developing a range of conditions but may not directly cause them.

This means that lowering homocysteine levels will not necessarily prevent a particular condition from developing.

High homocysteine levels may indicate deficiencies in vitamins B-6 and B-12 and folate.

A study in PLOS ONE found that there is a correlation between higher levels of homocysteine levels and deficiencies in folate and developing cancer. But scientists are unable to predict what type of cancer a person may be at risk for.

A doctor may recommend a person get a homocysteine level test if they show signs of deficiency in vitamin B-6, B-12, or folate.

A doctor may also recommend that a person has their homocysteine levels tested if they are at increased risk for heart disease or stroke or have a history of heart attacks and require monitoring.

A homocysteine test involves drawing blood. However, the test involves separating the blood cells and plasma quickly, so unless a doctor has the facilities to do this in the office, a person may need to go to an outside laboratory to get the blood test.

A person’s healthcare providers should provide instructions on where a person should go for the blood test.

Before the test, a doctor may ask the person fast for 10–12 hours, although they can drink water during this time. The doctor may also ask the person not to take medications or supplements before the test.

If the elevated levels are due to a deficiency in vitamins B-6 and B-12, or folate, a person may experience symptoms such as:

  • weakness
  • dizziness
  • sores on mouth or tongue
  • tingling in the feet, legs, hands, or arms
  • fatigue
  • pale skin

Vitamin B-6, B-12, and folate deficiencies are a common cause of higher homocysteine levels in some people. But other factors include:

  • family history
  • genetics
  • diet
  • smoking
  • alcohol
  • diabetes
  • rheumatoid arthritis
  • Crohn’s disease

An article in theJournal of Geriatric Cardiology notes that homocysteine levels may also increase as a person ages. Also, according to Food for the Brain, a not-for-profit educational charity, males are more likely to have higher levels than females.

According to a 2017 meta-analysis, healthcare professionals associate high homocysteine levels with all-cause mortality risks. For every 5 µmol/L increase in homocysteine levels, there was a 33.6% increase of all-cause mortality risk.

Potential conditions associated with high homocysteine levels include:

According to an article in Nutrition Journal, elevated homocysteine levels can also enhance the effects of hypertension, smoking, and increase inflammation.

A doctor will recommend a blood test for homocysteine levels if the person has symptoms of vitamin B-6, B-12, or folate deficiency. They may also run the test if the person already has risk factors for heart disease.

If a person’s test results come back with high levels of homocysteine, a doctor may need to run additional tests to determine the underlying cause.

In some cases, it may be due to not getting enough nutrients. Other people may have an underlying health condition that needs additional treatment.

Treatment will vary according to the underlying condition. For example, if a person has a vitamin deficiency, a doctor may prescribe or recommend taking supplements to correct the deficiency. They may also recommend the person make dietary changes to help decrease their levels.

Typically, people have low levels of homocysteine in their blood. An elevated level could indicate a deficiency in certain vitamins or folate and may increase a person’s risk of developing cardiovascular disease, cancer, and several other conditions.

It is possible to lower homocysteine levels through dietary changes and by taking supplements. However, a doctor may continue to monitor the person for signs of heart disease or other health conditions.

According to a 2017 review question, no evidence suggests that lowering a person’s homocysteine levels reduces the chance of developing cardiovascular events or cancer. However, the American Heart Association emphasize that a healthful diet can help maintain a healthy heart.