Evidence-Based Nutrient Recommendations

Should I Get My B12 Status Tested?



Serum B12 Levels

Vegans don’t need to get their B12 levels checked merely because they’re vegan. Rather, being vegan means that you should get a regular, reliable source of vitamin B12 from fortified foods or supplements.

About 2% of people do not absorb B12 well, a condition known as pernicious anemia. If you suspect that you might suffer from pernicious anemia, you can be tested for it.


Blood homocysteine level can be elevated in B12, folate, and vitamin B6 deficiency, and is linked with numerous chronic diseases although the role homocysteine plays is controversial. Vegans don’t need to have their homocysteine levels checked merely because they’re vegan, but some doctors recommend that all adults over age 45 have their homocysteine levels checked in order to catch a genetic predisposition to high homocysteine, which can often be successfully treated. It’s more important for vegans to obtain a reliable source of B12 than to have their homocysteine levels checked.

Methylmalonic Acid: Most Specific Test for B12 Status

Methylmalonic acid (MMA) builds up in the system when B12 status is poor. It’s the most specific test for measuring B12 status because B12 is the only necessary co-enzyme needed to keep levels low. MMA can be measured in both the urine and the blood. MMA provides a snapshot of what your B12 status is at a given moment.

Getting your MMA levels tested in the absence of a reliable source of B12 will most likely show it to be elevated. In other words, if you haven’t been obtaining B12, you can avoid the test and just assume your MMA is elevated. If someone is obtaining the recommended amounts of B12 and still has a highly elevated MMA level, it can indicate another condition, such as kidney disease or a B12 metabolism problem that can then be treated under the guidance of a physician.


It’s prudent to have homocysteine levels tested after age 45. Unless you suspect a B12 absorption or metabolic problem, there’s no reason to get MMA or B12 levels tested if you follow the recommendations in Daily Needs.

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  • If you have a question about whether it's okay to cut supplements in half or combine supplements to achieve the dose we recommend, the answer is “Yes.” Be aware that nutrient recommendations are only estimates—it's not necessary to consume the exact amount we recommend every single day.
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  • We cannot provide personal nutrition advice for specific health conditions. If you need private counseling, here's a list of plant-based dietitians and we especially recommend VeganHealth contributor Taylor Wolfram, MS, RDN, LDN.
  • We urge you to consult with a qualified health professional for answers to your personal questions.

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