Homocysteine

What is homocysteine?

Homocysteine (Hcy) is an amino acid. It’s a chemical in your blood that helps create proteins. Vitamin B12, vitamin B6 and vitamin B9 (folate) break down homocysteine to generate other chemicals your body needs.

A high level of homocysteine is harmful to the lining in your artery walls. It also may cause blockages in your blood vessels that lead to problems like a heart attack or stroke.

Without a healthy amount of homocysteine, you may feel some adverse effects. A homocysteine test can tell you how much of this amino acid you have in your blood. It should be five to 15 micromoles per liter (mcmol/L).

What does homocysteine do?

When it interacts with the B vitamins, homocysteine converts to two substances:

• Methionine, an amino acid and antioxidant that creates proteins
• Cysteine, an amino acid made from methionine — cysteine reduces inflammation, increases communication between immune cells and increases liver health

What causes high homocysteine levels?

High homocysteine levels could mean you have a medical condition. But other factors can affect your homocysteine (Hcy) blood levels, including:

• Getting older
• Being male or reaching menopause if you’re female
• Using tobacco products

What happens if I have too much homocysteine?

If you have more than 50 mcmol/L, the excess homocysteine (Hcy) may damage the lining of your arteries (blood vessels that carry oxygen-rich blood throughout your body).

Homocysteine can make it easier for atherosclerosis (fat and cholesterol buildup) to start. It can also make it worse. High homocysteine levels can also lead to blood clots or blood vessel blockages. Artery damage, atherosclerosis and blood clots raise your risk of:

• Heart attack
• Stroke
• Atrial fibrillation (a type of abnormal heart rhythm)

In a healthy person, homocysteine levels are around five to 15 mcmol/L. Nearly all that homocysteine converts to other proteins. Some people have mild (15 to 30 mcmol/L) or moderate (30 to 100 mcmol/L) levels of homocysteine. More than 100 mcmol/L is a severe level.

What are the common conditions and disorders that affect homocysteine?

Typically, homocysteine (Hcy) breaks down into other substances, and only small amounts of homocysteine remain in your blood. Some conditions interfere with this process and leave you with high homocysteine levels.

You may have too much homocysteine in your blood if you have:

• Chronic kidney disease
• Deficiencies (not enough) in vitamins B12, B6 or folate
• Dementia
• Heart disease
• Homocystinuria (when your body can’t process methionine)
• Hypothyroidism (underactive thyroid)
• Osteoporosis
• Psoriasis

What are the signs I may need a homocysteine test?

You may need a homocysteine blood test if you have symptoms of a vitamin B deficiency. Common symptoms of vitamin B deficiencies include:

• Dizziness
• Fatigue
• Heart palpitations
• Muscle weakness
• Skin color changes
• Tingling in your feet, arms or hands
• Tongue or mouth sores

How do I lower my homocysteine levels?

If you have high homocysteine levels, your healthcare provider may recommend taking supplements of:

• Vitamin B6
• Vitamin B12
• Folic acid (the human-made form of folate)

You may also get more of these nutrients by eating foods that contain them. But increasing your vitamin intake alone doesn’t reduce your risk of heart disease. You can lower your risk of heart disease by:

• Avoiding tobacco products
• Eating foods low in salt
• Being physically active at least 150 minutes a week
• Managing your blood pressure