Blog » Understanding Your Lab Tests: Vitamin B12 and RBC-Folate Levels (Folic Acid)

Understanding Your Lab Tests: Vitamin B12 and RBC-Folate Levels (Folic Acid)

The body needs thousands of nutrients. What we call “vitamins” are just the ones we cannot manufacture ourselves and must get from our diet.

Of all the known B-vitamins (of which there are eight: B1, B2, B3, B5, B6, B7, B9 and B12), B12 and B9 (Folate) levels are two of the most important to maintaining our physical, mental and emotional health.

Folate levels, for example, are routinely checked in pregnant women as deficiency can result in birth defects.

And if you’re low on energy, over the age of 60, on a restrictive vegetarian or vegan diet, or are having issues with memory, mood or neuropathy, many doctors will run B12 tests, as deficiencies have become common.

We know that reference ranges in labs only capture variation in a population.  

Just because a vitamin level is “normal” does not mean it’s sufficient. Do you really know what your optimal levels of B12 and folate should be, or how to get enough of these crucial vitamins?

In today’s article (the third in our “Understanding Your Lab work” series), you’ll learn exactly what you need to know about your B12 and folate levels and lab tests including:

  • Why you should get your levels checked
  • Symptoms of low B12 and folate
  • The optimal/functional ranges of B12 and folate
  • The root causes of deficiencies
  • How to optimize your levels safely

Why Get Your Levels Checked?

B12 and folate are considered the “heavy hitters” of the B-vitamins, which is why we we test for them at kNew Health.

One of the main reasons these two are so important, is because they have a symbiotic relationship which affects a key bodily function known as: methylation.

Methylation is a metabolic process that occurs in every organ and cell of the body at a rate of about 1 billion times per second.

Methylation affects your body in numerous ways, including how genes are expressed, neurotransmitter synthesis, hormone balance, and detoxification (to name but a few).

Therefore, if you’re not methylating properly you’re not detoxifying well, breaking down nutrients, expressing genes or producing energy properly, which can lead to a host of health concerns.

B12 and folate also play a role in other key bodily functions including:

  • Health of the entire nervous system, including the brain
  • Blood health (both plays a key role in the formation of healthy red blood cells)
  • DNA synthesis
  • Mood and memory
  • Muscle health

Symptoms of B12 Deficiency

B12 deficiency afflicts millions of adults, children and the elderly every year.

In fact, it is estimated about two-fifths of the population are overtly deficient.

This widespread B12 deficiency has somewhat puzzled the medical field, as many who are deficient consume adequate B12-rich animals foods and protein.

We’ll get into the “why” on this coming up, but some common symptoms of B12 deficiency include:

  • Low energy/fatigue
  • Cognitive decline such as memory loss, brain fog, trouble focusing, etc.
  • Muscle weakness
  • Anemia
  • Tingling in hands or feet (or other types of neuropathy)
  • Mental health issues such as depression, anxiety and paranoia
  • Impaired detoxification
  • Irritability
  • Difficulty walking or balancing

A special note on the mental health aspects of B12: our good friend, Dr. Kelly Brogan, holistic psychiatrist and author of the NYT best-seller: “A Mind of Your Own” once wrote:

One of the most remarkable papers I have read in the psychiatric literature was about a 57 year old woman who was treated with months of both antipsychotic and antidepressant medications and given two rounds of electroconvulsive treatment before anyone bothered to check her vitamin B12 level.” – Kelly Brogan,

In other words: it pays to have your B12 levels checked, especially if you’re prone to mental health issues of any kind.

Symptoms of Low Folate

Many symptoms of folate deficiency mirror those of B12. And like B12, folate is typically readily available from foods, especially fruits and vegetables.  Plus many packaged foods now fortified with “folic acid” to help prevent birth defects.

So, it stands to reason there are other causal factors at play beyond diet (hint: quality counts when it comes to your sources of folate).

Symptoms of folate deficiency include:

  • Fatigue
  • Low immunity
  • Poor digestion
  • Anemia
  • Canker sores
  • Moodiness/irritability/anxiety
  • Pale skin
  • Impaired detoxification
  • Developmental issues in-utero

But even if you don’t struggle with these symptoms yet, your levels of these key nutrients may be suboptimal and in need of proactive support before dysfunction develops.

What Are Your Optimal/Functional Ranges of B12 and Folate (how to read your blood test)?

If you learn one thing from this article, know this: low-normal B12 and folate levels will not cut it if you’re interested in preventative health and optimizing your well-being long-term.

If you want vibrant energy, a sharp mind, good muscle tone, efficient detoxification and a healthy nervous system, you want to come out on the high end of normal for these markers…not the low end.

Optimal/functional ranges of serum B12 range are likely:

  • 800-1000 ng/L

Optimal/functional ranges of red blood cell (RBC) folate range are likely:

  • 1000-1500 ng/ml

If you’re working with your own doctor or healthcare provider, keep in mind that different labs have different reference ranges, particularly for the folate.

The Root Causes of B12 and/or Folate Deficiencies

We hinted above that the root causes of B12 or folate deficiency may go beyond diet; let’s look at those causes now:

  • Diet—typically those following a vegan, vegetarian or very restrictive diet are at higher risk of B12 deficiency, because B12 is only found in animal foods.

Insofar as folate goes, anyone who is not eating enough dark leafy greens, nuts and seeds will be at higher risk of folate deficiency as these natural sources are the most absorbable.

The synthetic “folic acid” found in cheap supplements and fortified foods is typically poorly absorbed by much of the population, especially those with genetic mutations (more on this coming up).

  • Absorption issues—beyond diet, certain digestive health issues such as Leaky Gut Syndrome, gut microbial overgrowth/imbalances (e.g. SIBO), and H.Pylori infection can impair your body’s ability to absorb B12 and folate
    • In particular, we need ample stomach acid to prepare Vitamin B12 for absorption in the intestines, and we tend to make sub-optimal levels of stomach acid as we age, when we have hypothyroid function, and when we are stressed.
  • Autoimmune diseases—if you have an autoimmune disease like celiac or Crohn’s disease, it typically impacts your digestive health which can cause, or exacerbate, vitamin deficiencies
    • Pernicious anemia is also an autoimmune disease that directly—and dramatically—impairs Vitamin B12 absorption.
  • Medications—specific medications such as proton pump inhibitors and metformin, can have devastating impacts on your B12 levels, especially if taken long-term.
  • Genetic mutations—such as MTRR and MTHFR interfere with your body’s ability to store Vitamin B12 for ongoing use (requiring more frequent intake) or to produce methyl folate from the forms we typically take in (especially cheap folate found in most processed foods and mainstream vitamins), both of which can create deficiency.

How to Address Root Causes and Optimize Your B12 and Folate Levels Safely

At kNew Health, we often recommend dietary changes and, where appropriate, supplementation to achieve optimal B12 and folate levels quickly and safely.

For B12 supplementation we typically recommend:

  • 1000 mcg of methylcobalamin 1 -2 times daily

If you have a digestive issue, sublingual B12 (taken under the tongue) or a lozenge, is often your best choice to enhance absorption.

For folate supplementation, we typically recommend:

  • 400-800 mcg of methylfolate daily

Why do we recommend the methyl forms of B12 and folate?

Methylated B-Vitamins provide superior absorption even in the presence of genetic mutations like MTHFR.

If you’re deficient in both, it may work best to find a high-quality B-complex supplement to cover all your bases.

If a Digestive Issue is Impacting your Levels, your Health Coach may Recommend the Following

  • An elimination diet―is an affordable and accurate way to rule out trigger foods that may be harming your digestive tract, causing those pesky symptoms like reflux and impacting your ability to absorb B-vitamins.
    • “Trigger foods” to eliminate for a period of time may include gluten or other grains, dairy, sugar, soy and eggs.
  • Probiotic support―this may mean taking a multi-strain probiotic supplement and/or increasing your intake of probiotic-rich foods like kombucha, kim chi, cultured vegetables, real pickles, yogurt and kefir.
    • Probiotics can naturally increase synthesis and production of B-vitamins and other nutrients in the gut, such as B12 and folate respectively.
  • Digestive enzyme support―plant-based digestive enzymes or hydrochloric acid supplements offer an effective way to support digestion while you work on healing your GI tract. Food-based sources of enzymes such as papaya, pineapple cultured or raw vegetables, may also be recommended.

If you’re suffering from a more chronic condition such as an autoimmune disease or infection, your Health Coach may recommend additional measures and/or refer you to a functional medicine physician.

How Often to Track Your B12 and Folate Labs

This should be determined on an individual basis with your Health Coach or Functional Medicine practitioner.

If your B12 levels are very low and you’re experiencing life-altering symptoms, or if you’re pregnant and come back very low in folate, for example, re-testing may be recommended in as little as 1-3 months time.

Curious about how your B12 and folate levels may be impacting your health? We’re here to help.

All kNew Health members receive a B12 and RBC-folate lab workup as part of their initial assessment, along with a dedicated Health Coach to help you optimize your levels for the long-term.

-The Knew Health Team

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<a href="" target="_self">Joshua Rosenthal</a>

Joshua Rosenthal


Joshua Rosenthal MScED is a visionary in health and wellness. He is founder of the Institute for Integrative Nutrition, an online higher education school where students are trained as Health Coaches. Founded in 1992, the school has a global community of 100,000 graduates in 155 countries worldwide. Joshua is the author of many books and holds a Masters of Science degree in Education.