What if I told you that one tiny probiotic strain could impact not only your bloating and gut health but also your immune system, brain function, and even mood?
I’ve been deep in the probiotic rabbit hole lately – testing different strains, megadosing, tracking my body’s responses, and digging through my SelfDecode reports to see what my genetics say about my gut health.
I’ve gone through the research, experimented on myself, and narrowed it down to my top three probiotics—and this one is number one.
Out of everything I’ve tested, Bifidobacterium longum has been the most reliable for improving digestion, reducing bloating, and keeping my gut in check.
But what really blew me away was its impact on immunity and food allergies.
What is B. Longum?
Bifidobacterium longum is a type of probiotic—a beneficial bacteria that naturally lives in your gut.
Probiotics like B. longum play an essential role in your body, helping to break down food, regulate the immune system, and maintain a balanced gut microbiome.
While your gut is home to trillions of bacteria, not all of them are beneficial.
Some can lead to inflammation, digestive issues, and even mental health imbalances if they overgrow or if the good bacteria are outnumbered.
That’s where probiotics like B. longum come in.
This strain has been shown to support digestion, reduce bloating, strengthen the gut barrier, and even influence brain function by interacting with neurotransmitters like serotonin.
And depending on your genetics, you may need more support in these areas—especially if your body struggles with breaking down certain fibers, regulating inflammation, or producing enough beneficial gut bacteria on its own.
FUT2, Immunity, and B. Longum Colonization
The FUT2 gene plays a crucial role in determining whether you’re a secretor or non-secretor—meaning whether your body expresses specific sugars in bodily fluids like saliva, mucus, and the gut lining.
These sugars serve as a food source for beneficial gut bacteria, including Bifidobacterium longum.
Secretors provide an environment that helps B. longum thrive, while non-secretors have a harder time colonizing and maintaining high levels of this beneficial probiotic.
Your FUT2 gene variant determines which one you are, with the ‘AA’ genotype of the rs601338 SNP being non-secretor.
SelfDecode analyzed thousands of my genes – including the FUT2 gene – and put me at high risk for the flu, due to a weaker immune system.
B. Longum was at the top of my recommendations list, as it helps strengthen the gut barrier, increase microbial diversity, and decrease susceptibility to infections.
Food Allergies and HLA-DQ
A dysregulated immune system doesn’t just make you more susceptible to infections—it can also trigger food allergies. And that’s another area where B. longum shines.
The HLA-DQ genes play a key role in immune regulation, helping your body recognize which proteins are harmless and which are threats.
Certain variants, like HLA-DQ2 and HLA-DQ8, are linked to an increased risk of food allergies, making the immune system more likely to overreact to proteins in foods like gluten, peanuts, and dairy.
B. Longum can help regulate immune responses and improve gut barrier function, potentially mitigating food allergies and sensitivities.
One of the key mechanisms behind this is its production of indole-3-aldehyde (I3A), a metabolite derived from tryptophan.
I3A activates the aryl hydrocarbon receptor (AhR), which plays a crucial role in:
✅ Maintaining intestinal barrier integrity, preventing allergens from leaking into the bloodstream.
✅ Promoting regulatory T-cell function, which helps train the immune system to tolerate certain foods.
✅ Enhancing protective mucosal barriers in the gut, creating a stronger defense against allergens.
This is why understanding your genetic makeup is important to figure out what probiotics (or other supplements) you need to optimize your gut, immune system, mood, cognitive function, and so much more.
Is B. Longum good for you?
I won’t pretend that B. longum is perfect for everyone. As I said before, genetics plays a huge role.
Some people don’t notice a huge difference, and if your gut issues are more complex, you might need additional strains.
But when looking at my genetics and the lifestyle I lead, it’s hands down one of the best probiotics you can take.
If you’ve been trying to optimize your digestion, immune system, or even mood, B. Longum is absolutely worth considering.
But first, you’ll want to know exactly how your genetics influence your gut health, that’s where DNA analysis comes in.
With SelfDecode, you get a deeper understanding of how your body processes nutrients, probiotics, and more—and it’s been a game-changer in personalizing your supplement routine.
You don’t have to guess what works. You can test and know.
And if you end up trying B. Longum, let me know how it goes. I’d love to hear your experience.
