What Is a Healthy Homocysteine Number?
Clinical testing laboratories consider a homocysteine value between 5 to 15 µmol/L as healthy. Life Extension believes that an upper limit of 15 µmol/L is too high for optimal health. Studies indicate adults with homocysteine values ≥6.3 µmol/L are at increased risk of atherosclerosis (Homocysteine Studies Collaboration), heart attack and stroke.17 Homocysteine levels in the blood can increase due to age,18 prescription drug use (see the “Drugs that Raise Homocysteine Levels” section), declining ability to absorb vitamin B12,19 deteriorating kidney function,20 smoking,14 alcohol,16 coffee consumption,21 obesity,22 declining levels of physical activity,4 and inheriting a genetic polymorphism known as the MTHFR C677T variant in methylenetetrahydrofolate reductase (MTHFR).23 After age 50, a more practical target value for homocysteine is <8 µmol/L. Depending upon other factors, you may require larger-than-usual intakes of B vitamins to achieve a healthy blood level of homocysteine. Data from published studies reveal that there is no safe “normal range” for homocysteine. Epidemiological studies have shown that higher homocysteine levels are associated with higher risk, even at levels that are considered “normal.”24 Life Extension recommends a target of <8 µmol/L because published data, as well as our experience with homocysteine in tens of thousands of customers over more than 30 years, indicate that this threshold target is a realistic goal when taking optimal amounts of vitamins B6, B12, folate, TMG, and other homocysteine-lowering nutrients.25
The MTHFR C677T gene polymorphism is the single most important genetic determinant of blood homocysteine values in the general population. More than 40% of Hispanics and between 30‒38% of whites living in the United States inherit at least one copy of this gene,26 which impairs their ability to fully activate (methylate) folic acid to 5-methyltetrahydrofolate, the bioactive form of the B vitamin. Individuals who inherit this gene variant from both parents have a significantly higher (14‒21%) risk of vascular disease than those who do not.
For this affected group, taking the bioactive folate supplement, 5-MTHF, may be a better strategy. 5-MTHF is clinically tested, is highly bioavailable,27 can cross the blood‒brain barrier,28 and is unlikely to mask a vitamin B12 deficiency as folic acid can do.29 Those who carry this gene variant can safely reduce their risk of homocysteine-related health problems using an inexpensive, nonprescription natural folate supplement.