Homocysteine (Hcy) and Its Impact on Heart Health

What is Homocysteine?

Homocysteine is a compound that naturally forms in our body during the metabolism of the amino acid methionine (an essential amino acid). In healthy cells, homocysteine is rapidly converted into other products. The metabolism of homocysteine requires B vitamins: folic acid (folate), vitamin B12, vitamin B6, and riboflavin. Due to a deficiency of these B vitamins (or genetic factors or other pathophysiological conditions), homocysteine metabolism becomes impaired, leading to elevated homocysteine levels in the blood—known as hyperhomocysteinemia. This is a risk factor for vascular diseases, neurodegenerative diseases, and other clinical conditions. Vitamin B supplements are effective in lowering homocysteine levels in the blood but may have little to no effect on reducing the risk of vascular events.

Why is Homocysteine Important for Heart Health?

Elevated homocysteine levels can damage blood vessels, increasing the risk of heart diseases such as coronary artery disease, heart attack, or stroke. In fact, research has shown that high homocysteine levels can be a strong independent marker of risk for cardiovascular diseases.

Why and when is Homocysteine Testing Done?

The test is performed routinely, usually at a doctor’s request, during an internal medicine check-up for the following reasons:

• Assessment of cardiovascular risk (especially in older individuals or those with a positive family history of cardiovascular diseases)
• Suspected deficiency of folic acid and other B vitamins
• Suspected homocystinuria (a rare inherited condition that leads to the accumulation of homocysteine and methionine in the body)
• Malnutrition
• In drug and alcohol addicts

Factors Influencing Homocysteine Levels in the Body:

1. Age – Homocysteine levels can increase with age.
2. Gender – Homocysteine levels in women are generally lower than in men but tend to rise after menopause, which is linked to reduced estrogen production. However, the risk for women does not seem to increase with moderately elevated homocysteine levels.
3. Medication Use – Homocysteine levels may be elevated due to the use of certain medications, such as carbamazepine, methotrexate, and phenytoin.
4. Lifestyle Habits – Habits like smoking can raise homocysteine levels.

Reference Values for Homocysteine:

Most laboratory tests from reputable manufacturers have similar reference values. The expected levels in healthy individuals depend on age.