The FUT2 gene : A game changer in Gut health

Disclaimer: This is an educational and informative post, nothing in it is meant to take the place of medical treatment, neither does it claim to treat, cure or diagnose any condition.


Let’s first start with the basics. What is the FUT2 gene?

The FUT2 gene encodes the enzyme called fucosyltransferase 2. The FUT2 gene controls the production of a prebiotic called 2’-fucosyllactose (2’FL). It is an oligosaccharide present in human breast milk, it also has protection factors when it comes to gut health and brain health.


What will be covered in this article:

  1.  Whether you are a secretor or non-secretor
  2. Fut2 and your blood type
  3.  What Fucose is and it’s  function
  4. What B12 is and it’s functions
  5. How The Fut2 gene influences B12 absorption
  6. How the Fut2 gene influences breast milk
  7. How the Fut2 gene influences gut health


1. To secrete or not to secrete…that is the question


When I first learned that we are either a secretor or a non-secretor, I had no idea what this meant or even if it is was important.  I was not expecting to be taken down the rabbit hole. I feel like I have only scratched the very tip of the ice-berg and I no doubt that I have a lot more to learn.

So what does it mean to be a secretor or a non-secretor? To put it plainly,it simply means whether you produce 2’FL or not.

If you produce 2’FL it means you are a secretor and if you don’t, it means you are a non-secretor.


A secretor carries the AG or GG allele

  • Makes up 80% of the population
  • Produce fucose
  • Risk for higher BMI
  • lower vitamin B12 levels
  • increased risk for anaemia
  • The presence of the G allele increases one’s risk of developing psoriasis
  • advantage: higher prevalence of bidobacteria in gut
  • disadvantage: higher risk for rotavirus and novavirus and H.Pylori

A Non-Secretor carries the AA allele

FUT2 AA alleles are considered non-secretors:

  • make up 20% of the population
  • produce less fucose to line gut and impacts quality of breast milk
  • lower levels of beneficial bifidobacteria in their intestine
  • higher risk of developing autoimmune diseases
  • Non-secretors also often have higher serum vitamin B12 levels when they get their levels tested. However, this may not truly reflect the amount of B12 being transported into the cells. It could be that you have higher serum B12 because it is not getting into the cells.
  • Lower BMI
  • disadvantage: linked to an altered gut microbiome
  • advantage: have a protection against the adherence of certain bacteria like H.Pylori and novavirus.

2. Fut2 and your blood type


It starts getting complicated (hence the rabbit hole) when you start delving into it a bit deeper. A doctor by the name of Dr D’Adamo discovered the connection between the gene that codes for blood type and the FUT2 gene. The gene interacts with your blood type gene, and determines your ability to secrete your blood type antigens into body fluids and tissues.  (saliva, sweat, tears, vaginal secretions, semen, or digestive juices. )

So the secretor puts their blood type into the bodily fluids. (regardless of what blood type that is) Whereas a non-secretor puts little to none of their blood type into bodily fluids.


3.  A bit more about Fucose


So as I mentioned the 2’FL is a prebiotic that the FUT2 enzyme -fucosyltransferase 2 produces.

The gene puts fucose on the surface of the gut (the epithelial wall).

Fucose is a sugar that feeds the healthy bacteria in your body. If you don’t produce fucose to feed the healthy bacteria this leads to a change in the gut microbiome and increased inflammation.

The upside is that having no fucose on the lining  of the gut means that the H.pylori and novavirus can’t connect but the downside is that it can cause leaky gut.


4. B12 and it’s functions.


  1. Vitamin B12 is one of the most important nutrients we need for brain and neural function.
  2. It is a co-enzyme in many important processes including DNA synthesis, protein, lipid and carbohydrate synthesis.
  3. Vitamin B12 plays an important role in the formation and protection of the myelin sheath around the nerves which is needed for insulating your nerves and is also critical to your nervous system.
  4. A deficiency in B12 can lead to anaemia, neurological conditions and poor mental health.
  5. Vitamin B12 is naturally present in foods of animal origin such as fish, meat, poultry, eggs, and dairy products.


5. How The Fut2 gene influences B12 absorption


To understand how FUT2 can lead to intestinal permeability and also a decline in cognitive health you first need to understand the role of B12. Remember we said the secretors have an increased risk for not being able to absorb Vitamin B12. The FUT2 enzyme interferes with vitamin B12 absorption possibly due to having an infection which reduces stomach acid production and lowers the level of intrinsic factor which means less Vitamin B12 is absorbed.


6. How the Fut2 gene influences breast milk


Fucose is really found in the breast milk of lactating mothers and in the gut lining. Women who have low function FUT2 genes will have different breast milk than women who do not the same FUT2 genes. This difference in breast milk leads to a difference in gut bacteria when we are babies.This will still impact you as ad adult because it changes the quality of the mucous in your gut.


7. How the Fut2 gene influences gut health


Secretors: May need to take a B12 supplement as they normally have life-long lower B12 levels which makes them susceptible to an altered gut microbiome and intestinal permeability as well as gastrointestinal infections from H.Pylori or novavirus.

non-Secretors: Are susceptible to bacterial infections and could have an indirect lower risk of Vitamin B12 absorption resulting in higher serum B12 levels. (as they are not absorbing it).

I hope you enjoyed this article. It took me a long time to compile because I wanted to bring across all the points (that I know of) that this particular gene relates to, especially related to gut health.


If you are interested in finding out if you carry te FUT2 gene please contact me. I am an accredited genetic practitioner and our tests are available in over 50 Countries worldwide!


Sources besides my training:

Leave a Comment

Your email address will not be published. Required fields are marked *