For years I took a B Complex vitamin and had no idea what those B vitamins were actually responsible for. I mean, besides folate (vitamin B9) do you know what all the different B’s actually do?

Well, I’m gonna tell ya and it might totally blow your mind. Who knew a vitamin lesson could be this thrilling right?!

B1 vitamin facts

There are 8 B vitamins and altogether they are known as the B Complex of vitamins. We’ve got:

  • Vitamin B1 (thiamine)
  • Vitamin B2 (riboflavin)
  • Vitamin B3 (niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)
  • Vitamin B7 (biotin)
  • Vitamin B9 (folate)
  • Vitamin B12 (cobalamin)

What do B complex vitamins do?

Each of the B vitamins provides a different service to the body but they also work synergistically. The B complex is responsible for energy generation, metabolism, and the synthesis and breakdown of fats, carbohydrates, proteins, amino acids, steroid hormones and neurotransmitters. Yeah, they are kind of a big deal. And keep in mind they are water soluble so they need to be replenished daily.

The MTHFR gene and its impact on B complex vitamin absorption:

We all have a gene called the MTHFR gene. Upon completion of the Human Genome Project in 2002, it was discovered that many people have a variant of this gene – about 60% of the US population in fact! And 40% of British and Australians too. You’re probably wondering what on earth the MTHFR gene is huh? Well, it’s actual name is methylenetetrahydrofolate reductase (way too long for us unscientific folks to pronounce) and it if you have the gene defect or mutation, it’s more than likely that you are not absorbing and utilizing the B complex vitamins efficiently.

Just to clarify, these are the different variants that show up most often:

  • MTHFR 677CC = a normal MTHFR gene – this means you’re all good!!
  • MTHFR 677CT = a heterozygous variant which is one variant – not great but better than two mutations
  • MTHFR 677TT = a homozygous variant which is two variants – this is what I have and I def have some issues
  • MTHFR 1298AA = a normal MTHFR gene – again all good!
  • MTHFR 1298AC = a heterozygous variant which is one variant – not great but better than two mutations
  • MTHFR 1298CC = a homozgyous variant which is two variants – will cause more issues than just one mutation
  • MTHFR 677CT + MTHFR 1298AC = a compound heterozygous variant which is one variant from two different parts of the gene – this seems to be the worst form of the variant.

Okay back to B vitamins. When we are not getting enough of the B Complex vitamins, a lot of issues can arise. For women in particular, the list is even longer.

When we are deficient in B vitamins, these symptoms and conditions tend to show up:

  1. Deficiency in B12 results in infertility by causing changes in ovulation or development of the ovum or changes leading to defective implantation, and ultimately miscarriage. In fact, many women with this mutation have multiple miscarriages before finding out the main cause is this gene.
  2. Deficiency in Folate (B9) can result in pre-eclampsia and neural tube defects in babies.
  3. Depression, anxiety, PMS, PMDD, post-partum depression, chronic fatigue and fibromyalgia. Pregnancy can exacerbate a B12 deficiency because high amounts of B12 are needed by the fetus, thus leaving the woman more depleted than she was pre-pregnancy and setting her up for post-partum depression.
  4. Higher rates of anemia in women who are still cycling and women who are pregnant – see #6 below.
  5. Thyroid problems – high copper and other heavy metals can inhibit thyroid function – see #6 below.
  6. Abnormalities in the cells of the reproductive tract, cervix and uterine lining which may be diagnosed as cervical dysplasia.

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Here’s an excerpt on the MTHFR gene from the website – a seriously great site by the way!


What a healthy MTHFR gene does for you

When it’s all working right, the MTHFR gene begins a multi-step chemical breakdown process, aka methylation, which in simplified terms, is like this:

  • The MTHFR gene produces the MTHFR enzyme.
  • The MTHFR enzyme works with the folate (vitamin B9), breaking it down from 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate
  • 5-methyltetrahydrofolate helps convert the amino acid homocysteine down to another essential amino acid, methionine, which is used by your body to make proteins, utilize antioxidants, and to assist your liver to process fats. Methionine helps with depression and even inflammation. It also helps convert estradiol (E2) into estriol (E3)!
  • Methionine is converted in your liver into SAM-e (s-adenosylmethionine), which is anti-inflammatory, supports your immune system, helps produce then breakdown of your brain chemicals serotonin, dopamine and melatonin, and is involved in the growth, repair and maintenance of your cells.

A proper methylation pathway like the above is going to mean you will have a better chance of eliminating toxins and heavy metals, which can reduce your risk for cancer and other health issues.

What a defective MTHFR gene does to you

  • It produces a defective MTHFR enzyme of different varieties i.e. it functions less than optimally, such as performing at only 40% of its capacity, or 70% of its capacity. It can mean you won’t break down toxins well.
  • The defective enzyme doesn’t break down folate vitamins properly (of which folic acid is one), which can cause high homocysteine, which can increase your risk of coronary heart disease (arteriosclerotic vascular disease or venous thrombosis), and related heart and BP conditions, as well as increasing your risk for dementia.
  1. Homocysteine is poorly converted to glutathione, which is your body’s chief antioxidant and detoxifier. You are then more susceptible to stress and toxin buildup.
  2. Homocysteine is poorly converted to methionine, and less methionine can raise your risk of arteriosclerosis, fatty liver degenerative disease, anemia, increased inflammation, increased free radical damage… and produce less SAM-e
  3. Less SAM-e can increase depression
  4. And more broadly, an MTHFR defect can increase your risk of a variety of cancers (including breast and prostate cancer), stroke, heart problems, congenital defects, depression, IBS (irritable bowel syndrome), miscarriages, migraines, chemical sensitivities and many conditions.
  5. You can find yourself with high folate or high B12. i.e. your body will have problems converting inactive forms of folate and B12 to the active forms. So the inactive folate or B12 will simply build up in your serum, also inhibiting the active forms. 
  6. You may find yourself with high mercury, or high copper, or high other heavy metals….though not always. High copper can cause low iron levels.
  • The journal Molecular Psychiatry states that “Schizophrenia-like syndromes, bipolar disorder, Parkinson’s disease, Alzheimer’s disease and vascular dementia have all been associated with one or more mutations of the MTHFR gene”.  (2006;11, 352–360)


I know by now you’re wanting to find out how you can deal with this. Luckily, there are a number of easy solutions.

NOTE: If you find that your ‘folic acid’ or your B12 lab test levels are high this could be an indicator that you have a MTHFR gene variant. This is because a defect in the gene prevents your body from utilizing inactive forms of these B vitamins, so they go unused by the body and end up being too high. These high inactive forms of the B vitamins then block the active forms from being utilized. This is obviously a big problem!

Additionally, high homocysteine levels are another indicator that you may have this gene variant.

Here’s what you should do if you have an MTHFR genetic variant:

1. The first thing you need to do is avoid any supplements that have synthetic forms of the B vitamins in them. For instance, any supplement with folic acid is no good – this is just the synthetic, inactive form of folate.

I often recommend supplements with the methylated (active) forms of the key B vitamins but PLEASE NOTE, these may not work for you depending on the type of variant you have. If you are double homozygous (both your MTHFR genes are variants), methyl folate and methyl-B12 supplementation can cause problems for you. Also, you should not consume high doses of niacin (vitamin B3), because it can hinder methylation.

If you experience any negative effects – severe anxiety, panic, headaches, migraines, insomnia, palpitations, rash and achy joints – please discontinue use of methyl-folate products and seek the help of a trained practitioner who can help you get to the root cause.

You can find a practitioner on Dr. Ben Lynch’s website. He is a leading expert on MTHFR variants and he’s also got a great post on preventing methylfolate side effects

This is what the supplement label should say:

  • Vitamin B6 (as Pyridoxal 5′-Phosphate or P5P)
  • Folate (as L-5-Methyltetrahydrofolate or 5-MTHF from L-5-Methyltetrahydrofolic Acid)
  • Vitamin B12 (as Methylcobalamin)

I recommend Thorne Research Basic B Complex or Seeking Health B Complex Plus.

2. Avoid any processed foods that contain folic acid.
These include packaged or boxed fortified breads, baked goods and cereals – these are foods that have had all their B vitamins stripped out of them in the processing and refining stage and then they have been re-fortified with synthetic B vitamins.

3. Consume more healthy foods that contain folate – leafy green vegetables, broccoli, brown rice and quinoa etc.

4. Get tested if you’re really curious. Visit, a website that offers a full genetic test. They only provide the raw genetic data though, so once you get your results from 23andme, you’ll need to  upload it at either of the sites below in order to determine your methylation information:

  • GeneticGenie – upload your data and you’ll get a report back. You can compare it to the information at the top of the post on the different MTHFR mutations.
  • – Dr. Amy Yasko’s website. She is a genetic genius!

If you have specific health concerns that you think are related to your genes, then I recommend working with an experienced practitioner who can create a plan for your unique genetic makeup.

5. Detoxify detoxify. Because your body’s detoxification processes are so limited you need to help her out. Support your liver with a product like Gaia Herbs Milk Thistle or Thorne Research Liver Cleanse.  Start sweating – in an infrared sauna or steam room, through exercise and take epsom salt baths – 2-3 times a week.