B Vitamin Cheat Sheet for Optimal Conception

Poked. Prodded. Questioned.

Women who are struggling to get pregnant on their own will likely be submitted to a barrage of testing, questioning, supplementation, etc.

It can all seem like an overwhelming whirlwind.

  • How do we know what tests to get?
  • How are we supposed to know what to look for in our results?

There’s nothing worse than submitting yourself to multiple blood tests and consultations all to find that ‘everything looks normal!’

Ok great, now what?

But that’s just it – do things REALLY look normal? Or do your levels indicate something DEEPER?

As a Functional Nutrition Practitioner, I am trained to read between the lines and sift through the data to find any nuances indicating a root cause to your fertility challenges.

One such area I want to get into is that of your B vitamins. Many of us will be tested for B Vitamin Deficiency including: folate, B12& B6. And many of us will have a deficiency!

In this post we will cover WHY it’s important to have adequate B Vitamin levels, WHAT ranges to shoot for in your lab results, WHERE to focus your energy if your levels are low, and HOW to revitalize your B Vitamin levels for a better chance of getting/staying pregnant.

WHY B Vitamins are Important for Fertility:

1. B Vitamins decrease the risk of neural tube birth defects in proportion to the duration of supplementation

Meaning, you should plan to prepare for pregnancy by taking the right amount of B Vitamins for a minimum of 4 months, a year is even more beneficial. [i]

2. B vitamins increase likelihood for a fertilized egg to implant

This is true for both natural conception & the use of ART (including IVF a& ICSI) [ii]

3. B Vitamins are critical for Liver detoxification

The liver is the primary organ for detoxification, meaning it neutralizes & removes any unwanted chemicals. These metabolites are then eliminated via urine & stool.

This means a healthy working liver is just as important as healthy working bowels. If you aren’t pooping at least 1x/day, we have detoxification issues.

4. B Vitamins are critical for methylation

Methylation is a toxin-removal method necessary for heavy metal removal, neurotransmitter & hormone regulation, & histamine metabolism.

B12, B6 & folate support methylation which is involved in reducing and balancing high levels of inflammatory homocysteine (linked to anxiety & brain fog) [iii, iv]

5.  B Vitamins are critical for stress management

Methylation is also responsible for gene expression, repairing DNA, moderating immune & inflammatory processes, & maintaining mood as well as a healthy nervous system. It’s vital for stress resilience and recovery.

Women with MTHFR mutation may experience recurrent pregnancy loss due to high homocysteine levels [v]

According to the findings, reducing homocysteine levels through B vitamin supplementation prevented miscarriages.

Signs of high inflammatory homocysteine levels include fatigue, chronic pain, difficulty losing weight or if you need a long time to recover from exercise.

WHAT Should Your B Vitamin Levels Be For Fertility

Request a Blood test

Many GPs will test your folate and B12 levels, so ask for this general workup to see where your levels are at

Remember, we want our levels to be within the “Functional Lab Range” which means OPTIMAL HEALTH requirements:

  • Folate (plasma): 2-10 ng/mL
  • B12: 200-900 ng/mL
  • Ferritin: 70-90 ng/mL


Consider these 2 root causes:

  1. Your digestion / absorption
  2. Your genetics


Low stomach acid (common for stressed / under-nourished women) can lead to Low B12 absorption

Pepsin cleaves B12 from the protein molecule, intrinsic factor binds with B12 and enters the small intestine where intrinsic factor is then degraded and B12 is absorbed into circulation

If we don’t have enough pepsin/intrinsic factor then B12 is not absorbed

Same with iron

A B12 and iron deficiency often go hand in hand.


Because stomach acid converts ferric iron (iron in the for of ferric salts Fe(OH) and FePO4) from food to ferrous iron (Fe2+) which can then be absorbed by the brush border in the small intestine (measured in blood levels as ferritin).

Only 5% of dietary iron is absorbed and occurs in the small intestine.

So simply being told to ‘eat more red meat’ might not be enough. Instead, optimizing stomach acid production may be in order


Remember all that talk about methylation above?

Well consider this, up to 60% of people in the US have a genetic mutation that makes it challenging for their bodies to methylate!

Think of methylation as the biological switch that turns on and off a host of systems in the body

So if we aren’t able to methylate adequately, we can’t detoxify, we can’t remove excess hormones, we can’t regulate our neurotransmitters & moods…YIKES!

Genes involved in folic acid metabolism:

The MTHFR gene codes for the enzyme that is vital in the last step of converting folic acid into the active form used by the body. People with the  MTHFR C677T variant have decreased enzyme function.

Check your genetic data for rs1801133 (MTHFR C677T):

  • G/G: normal (wildtype)
  • A/G: one copy of C677T allele (heterozygous), MTHFR efficiency reduced by 40%
  • A/A: two copies of C677T (homozygous), MTHFR efficiency reduced by 70 – 80%

Another MTHFR variant, A1298C, also reduces the enzyme function. Researchers find that the variant increases the risk of recurrent miscarriages. [vi, vii]

Check your genetic data for rs1801131 (MTHFR A1298C):

  • TT: normal (wildtype)
  • GT: one copy of A1298C allele (heterozygous), MTHFR efficiency slightly reduced
  • GG: two copies of A1298C (homozygous), MTHFR efficiency reduced

Genes involved in vitamin B12:

The COMT gene codes for an enzyme that breaks down the neurotransmitters, dopamine and norepinephrine. Understanding your COMT gene can help you determine the best type of vitamin B12 for your body (there are 4 types).

COMT rs4680 changes the activity of the enzyme.

The G/G genotype has higher COMT enzyme activity, which leads to quicker clearance of dopamine and norepinephrine.

The A/A genotype has lower COMT enzyme activity. People with this genotype sometimes find that taking both methylcobalamin and methylfolate together leads to mood swings with anxiety or irritability. The theory is that too many methyl groups flooding in leads to a rapid rise and fall of dopamine levels. [viii]

Check your genetic data for rs4680:

  • G/G: higher COMT activity, supplement with methylcobalamin
  • A/G: intermediate COMT activity
  • A/A: 40% lower COMT activity, supplement with adenosylcobalamin or hydroxocobalamin

HOW to Revitalize Your B Vitamin Levels


B6 Food sources: Tuna, banana, turkey, liver, salmon, cod, spinach, bell peppers, and turnip greens, collard greens, garlic, cauliflower, mustard greens, celery, cabbage, asparagus, broccoli, kale, Brussels sprouts, chard.

B12 Food sources: Clams, oysters, muscles, liver, caviar (fish eggs), fish, crab, lobster, beef, lamb, cheese, eggs.

Folic Acid Food sources: liver, lentils, pinto beans, garbanzo beans, asparagus, spinach, black beans, navy beans, kidney beans, collard greens

Iron Food sources: Lentils, spinach, tofu, sesame seeds, kidney beans, pumpkin seeds (raw), venison, garbanzo beans, navy beans, molasses, beef


Many of you may already be taking a prenatal or B complex vitamin. Good on you! But be sure to look for the methylated (or active) versions of the vitamin so that you aren’t missing out on bioavailability.

Here’s a cheat sheet for you:

  • Instead of Folic Acid =>> 5-MTHF (active folate)
  • Instead of B12 =>> Methylcobalamin (active B12)
  • Instead of B6 =>> Pyridoxal 5’ Phosphate (active B6)
  • Instead of B2 =>> Riboflavin 5’ Phosphate (active B2)

We love Thorne Basic Prenatal because it provides the bio-available forms of B vitamins in adequate amounts for the preconception phase.

Getting enough folate and vitamin B12 is essential for a successful pregnancy. Knowing your genetics and working with a fertility expert can help you narrow down the best choices for your body.


[i] Bukowski R, Malone FD, Porter FT, et al. Preconceptional Folate Supplementation and the Risk of Spontaneous Preterm Birth: A Cohort Study. Fisk NM, ed. PLoS Medicine. 2009;6(5):e1000061. doi:10.1371/journal.pmed.1000061.

[ii] Gaskins AJ, Chiu Y-H, Williams PL, et al. Association between serum folate and vitamin B-12 and outcomes of assisted reproductive technologies. The American Journal of Clinical Nutrition. 2015;102(4):943-950. doi:10.3945/ajcn.115.112185.

[iii] Van Dam et al. Arch Gerent Ger. 2009; 48: 425-30.

[iv] Smith et al. PLoS ONE. 2010; 5 (9). Smith et al. PLoS ONE. 2010; 5 (9). 3 Calder et al.

[v] Reprod Toxicol. 2017 Sep;72:159-163. doi: 10.1016/j.reprotox.2017.07.001. Epub 2017 Jul 6.The importance of folate, vitamins B6 and B12 for the lowering of homocysteine concentrations for patients with recurrent pregnancy loss and MTHFR mutations. Serapinas, Boreikaite, Bartkeviciute, Bandzeviciene R3, Silkunas M2, Bartkeviciene D2.https://www.ncbi.nlm.nih.gov/pubmed/28689805

[vi] Bueno, Olalla, et al. “Common Polymorphisms That Affect Folate Transport or Metabolism Modify the Effect of the MTHFR 677C > T Polymorphism on Folate Status.” The Journal of Nutrition, vol. 146, no. 1, 2015, pp. 1–8., doi:10.3945/jn.115.223685.

[vii] Nair, Rohini R., et al. “Association of Maternal and Fetal MTHFR A1298C Polymorphism with the Risk of Pregnancy Loss: a Study of an Indian Population and a Meta-Analysis.” Fertility and Sterility, vol. 99, no. 5, 2013, doi:10.1016/j.fertnstert.2012.12.027.

[viii] Shorter, Kimberly R., et al. “Consequences of Dietary Methyl Donor Supplements: Is More Always Better?” Progress in Biophysics and Molecular Biology, Pergamon, 2 Apr. 2015, www.sciencedirect.com/science/article/pii/S0079610715000437.

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