How to choose the right probiotic for gut immunity

Strains That Work for Gut, Mood & Immunity

By Dr Herna de Wit, PhD

With the supplement shelves overflowing with probiotics claiming to do everything from “healing your gut” to “boosting your mood,” it’s easy to feel overwhelmed or sceptical.

And rightly so.

The truth is, not all probiotics are created equal. Many don’t even survive long enough to make it to your gut, let alone deliver the benefits promised on the label.

As a biochemist and science communicator, I approach probiotics with both scientific rigour and practical care. This isn’t about jumping on wellness trends. It’s about using microbes as precision tools for specific health goals.

Why Most Probiotic Supplements Don’t Work and How to Spot the Difference

Let’s start with the basics. Probiotics are living microorganisms that, when taken in the right amounts, offer health benefits primarily by supporting your gut microbiome.

But here’s where most products fall short:
They list broad species like Lactobacillus or Bifidobacterium without naming the strain. And that’s a big problem.

Think of it this way: not all Lactobacillus bacteria behave the same, just like not all dogs are golden retrievers. It’s the strain (e.g., Lactobacillus rhamnosus GG) that determines what the probiotic does in your body.

If the strain isn’t clearly listed and backed by clinical research, we simply don’t know if it works, or for what.

Probiotic Strains That Work: LGG and BB-12 Backed by Science

Personally, I prioritise two strains that are among the most studied and well-documented in the world:

• Lactobacillus rhamnosus GG (LGG)
  
• Bifidobacterium animalis subsp. lactis BB-12
  

These have been shown to support a wide range of benefits, including:

• Digestive health and regularity
  
• Immune resilience (especially during cold and flu season)
  
• Mental well-being, particularly under stress
  

In one clinical study, students taking these strains experienced improved quality of life during periods of upper respiratory infections: a testament to the gut–immune–brain connection we now understand more deeply than ever.

My Checklist for Choosing a High-Quality Probiotic Supplement

Buying a probiotic should be more than picking the prettiest label or the one with the longest list of bacteria. Here’s my personal checklist:

1. Strain specificity
   
   • The exact strain name (e.g., LGG, BB-12) must be listed, not just the species.
     
2. Human clinical evidence
   
   • I choose products supported by randomised controlled trials, not just in petri dishes.
     
3. Stability and survivability
   
   • The bacteria must be able to survive both storage and stomach acid. I favour products using delayed-release capsules or protective coatings that enhance their journey through the digestive tract.
     
4. Shelf-stable, if possible
   
   • While refrigeration isn’t a bad thing, shelf-stable options tend to be more convenient and less sensitive to temperature changes.
     

Why Probiotics Aren’t One-Size-Fits-All, And What to Consider Instead

Here’s where things get even more important:
Your ideal probiotic depends on your current health, lifestyle, and even geography.

Someone recovering from antibiotics may need different support than someone navigating IBS, pregnancy, menopause, or chronic stress. Similarly, women may benefit from strains tailored to vaginal health, mood stability, or immune modulation, depending on life stage and environment.

That’s why I view probiotics not as daily staples for everyone, but as targeted tools, part of a personalised wellness approach, not a blanket solution.

How to Support Gut Health Beyond Supplements

Supplements can be powerful, but they work best when paired with a gut-friendly lifestyle. That includes:

• Eating diverse, fibre-rich foods (30+ plant types per week, if possible). This is where FiiHii products come in.
  
• Adding fermented foods like kefir, sauerkraut, miso, and natural yoghurt
  
• Managing stress and prioritising sleep, both of which shape your microbial balance
  
• Avoiding unnecessary antibiotics, which can disrupt your microbial terrain
  

Think of probiotics as the cherry on top: they can tip the balance, but they can’t replace a nourishing base.

How to Choose a Probiotic That Benefits Your Health

When it comes to probiotics, flashy marketing doesn’t always equal effectiveness. What matters most is scientific backing, strain transparency, and alignment with your personal needs.

Whether you’re supporting digestion, mood, immunity, or all three, the right probiotic can offer real, measurable benefits. But only if you choose wisely.

So the next time you’re tempted to grab a trendy blend off the shelf, pause for a moment.

Check the strain. 

Read the research. 

And ask yourself: What do I actually need this probiotic to do?

That’s the start of a smarter, more empowered wellness journey rooted in science, not hype.

References:

1. Yin, Z., Wang, Y., Feng, X., Liu, C., Guan, X., Liu, S., Long, Z., Miao, Z., He, F., Cheng, R., Han, Y., & Li, K. (2024). Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB‐12 promote infected wound healing via regulation of the wound microenvironment. Microbial Biotechnology, 17. https://doi.org/10.1111/1751-7915.70031. 
2. Szajewska, H., & Hojsak, I. (2020). Health benefits of Lactobacillus rhamnosus GG and Bifidobacterium animalis subspecies lactis BB-12 in children. Postgraduate Medicine, 132, 441 – 451. https://doi.org/10.1080/00325481.2020.1731214. 
3. Smith, T., Rigassio-Radler, D., Denmark, R., Haley, T., & Touger-Decker, R. (2012). Effect of Lactobacillus rhamnosus LGG® and Bifidobacterium animalis ssp. lactis BB-12® on health-related quality of life in college students affected by upper respiratory infections. British Journal of Nutrition, 109, 1999 – 2007. https://doi.org/10.1017/S0007114512004138.