Elevated homocysteine levels in the blood are linked to an increased risk of cardiovascular and neurological diseases. Keeping homocysteine levels within an optimal range is essential for overall health, as high levels contribute to inflammation and vascular damage.

Why Test for Homocysteine?

Research shows that nearly 30% of individuals over 65 and more than 40% of those aged 80 and older have elevated homocysteine levels.

Hyperhomocysteinemia, or high homocysteine, has long been recognized as a risk factor for:

• Cardiovascular diseases: Ischemic heart disease, heart attack, sudden cardiac death, premature coronary artery disease, carotid artery stenosis (narrowing), blood clots, stroke, and peripheral vascular disease.
• Neurological conditions: Recent studies identify high homocysteine as an independent risk factor for dementia and cognitive decline. Homocysteine levels exceeding 15 µmol/L are associated with nearly double the prevalence of dementia.
• Parkinson’s disease: A 2017 study found that individuals with Parkinson’s disease and cognitive impairment were more likely to have elevated homocysteine levels.

By measuring homocysteine levels, healthcare providers can take a proactive approach to disease prevention and overall well-being.

Understanding Homocysteine Test Results

• Optimal levels: Below 10 µmol/L
• Borderline levels: 10-15 µmol/L
• Hyperhomocysteinemia: Greater than 15 µmol/L

Classification of Hyperhomocysteinemia

• Moderate: 16-30 µmol/L
• Intermediate: 31-100 µmol/L
• Severe: >100 µmol/L

Causes of Elevated Homocysteine Levels

Several factors can impair homocysteine metabolism and lead to elevated levels, including:

• Underlying medical conditions: Cancer, diabetes, kidney disease, thyroid disorders, homocystinuria
• Vitamin deficiencies: Low levels of folate, vitamin B6, and vitamin B12 (most common causes)
• Dietary factors: Excessive alcohol, coffee, and methionine-rich foods
• Genetic predisposition: Variations in the CBS and MTHFR genes
• Aging

Health Risks of High Homocysteine

Elevated homocysteine damages the inner lining of blood vessels, triggering inflammation and oxidative stress. This increases the risk of:

• Atherosclerosis: Thickening and hardening of arteries due to plaque buildup
• Blood clots: Increased risk of stroke and heart attack

Regular monitoring and management of homocysteine levels can play a key role in reducing these risks and supporting long-term health.

There is growing evidence that homocysteine is neurotoxic and decreases blood perfusion to the brain. Elevated levels are associated with neurodegeneration progression, as observed in diseases like Alzheimer’s disease. 

Strategies to Lower Homocysteine Levels

Addressing high homocysteine through dietary modifications includes moderating alcohol and coffee consumption and adequately consuming foods rich in folate, vitamin B6, and vitamin B12.

Some of the foods with the highest content of these vitamins are listed below:

Folate: spinach, liver, asparagus, and brussels sprouts
Vitamin B6: fish, organ meats, potatoes, non-citrus fruits
Vitamin B12: fish, meat, poultry, eggs, dairy 

Eating a high-protein diet has also been shown to elevate homocysteine levels. Methionine is found in high quantities in the standard American diet, concentrated in foods like meat, fish, poultry, dairy, and eggs. Limiting the intake of these foods may prevent hyperhomocysteinemia. 

Supplements to Lower Homocysteine Levels

Studies have demonstrated the efficacy of B vitamin supplementation in reducing homocysteine levels.

If your homocysteine is over 10 micromoles per liter, you can lower it by taking B6, B12 and folate. If your homocysteine is above 10 start by taking the pyridoxal-5-phosphate (P5P) form of vitamin B6, 20-to 50 milligrams each day; the methylcobalamin (methyl-B12) and adenosylcobalamin forms of B12, 1 milligram in total each day; and the methyltetrahydrofolate (methyl-folate), starting with 0.8 milligrams (and as high as 5 milligrams) each day.

After three months, recheck the homocysteine to make sure it has dropped to 10 micromoles per liter or lower. In the uncommon cases in which it hasn’t, simply add 500 milligrams daily of glycine betaine (also called trimethylglycine).

Re-check homocysteine in another three months. 

If still high reduce the methionine (the amino acid from which the body makes homocysteine) in your diet by limiting consumption of foods such as nuts, beef, lamb, cheese, turkey, pork, shellfish, soy, eggs, dairy and beans.

Research suggests that omega-3 fatty acids effectively reduce homocysteine levels, especially when simultaneously taken with B vitamins. 

Oral N-acetyl cysteine (NAC) supplementation may be considered for preventing vascular events and treating hyperhomocysteinemia. Four weeks of oral NAC dosed at 1.8 grams daily resulted in reductions of serum homocysteine by 11.7% and significant reductions in systolic and diastolic blood pressure.