It is increasingly being recognised that having a ‘healthy’ gut microbiome can be a powerful way to build long term health for a developing baby. It also starts with the mother. The best known route for this is the probiotic which is an attempt to add ‘good’ bacteria to the gut, however, one effective yet more overlooked route is the prebiotic which is essentially feeding the existing bacteria that you have. We take a look at what the science says and where you can find these.

By now, we know that one route to improving your chances of a healthy hormonal balance and the healthy development of your baby’s brain and immune system is ensuring your gut is in a good state.

What’s a ‘good state?’ At this point, given the relatively early stage science is at with understanding the gut microbiome, we mean ensuring that the microbes within the gut are diverse and there are no major imbalances.

How do we achieve this?

The area that gets by far the most attention is of course probiotics (note the ‘o’ here), or the attempt to add ‘good’ bacteria to the gut. This can come in various forms: through fermented foods, fecal transplants (yes) and even supplements. In fact, this has become big business in recent years. Science-wise, as it stands now, the effectiveness of probiotics you can buy yourself in store is relatively shaky in terms of showing real benefit. More success has been shown using specific targeted strains in a clinical setting, however, one easy and powerful way that has been shown to make a positive difference is via what you eat. This has been shown to be able to change the makeup of your microbiome in as little as 24 hours.

Probiotic supplements may not be the slam dunk that some claim, however, Prebiotics (note the ‘E’) are looking a bit more interesting and here’s why….

What is a Prebiotic?

Well, in very simple terms, instead of adding bacteria in to the gut microbiome (at least in theory) prebiotics feed the existing bacteria in your gut. They are usually starches which the body itself cannot digest/absorb but the bacteria within your gut can – essentially feeding them directly. That’s what we want.

Glenn Gibson and Marcel Roberfroid first defined a prebiotic as ‘A non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health.’

We now know that it is more than ‘one’ or a ‘limited number’ and, as a result, the definition has since been updated and that the possibilities are actually much more extensive. It is likely in fact that prebiotics feed and stimulate a whole host of bacteria in the gut.

The other good thing they do is to help with the production of another wondrous thing: The production of Short Chain Fatty Acids. What are these?  SCFAs are actually pretty fascinating (promise!) so well worth checking them out. In short though, they have been linked to helping with all kinds of good stuff in the body, including fighting against chronic inflammation (which has been shown to be a common underlying cause of many chronic conditions) and also helping the body’s own filter mechanism: the gut, and specifically the gut lining. Essentially, this helps to make sure what is needed gets in and what is not needed is passed out of the body.

Bottom Line: research has shown prebiotics to positively contribute to what we want: improvement in gut barrier function, immunity, reduction of potentially pathogenic bacteria (e.g., clostridia), and enhanced SCFA production.

Question is: Do they actually work?

Once again, studies here aren’t exactly water tight or entirely conclusive, however ‘Inulin, oligofructose, and FOS have been extensively studied as prebiotics, and have been shown to significantly increase fecal bifidobacteria at fairly low levels of consumption (5–8 g per day)’ (1)

We also know that there has been some evidence of improved immune function as a result: ‘Oligofructose consumption was found to reduce febrile illness associated with diarrhea or respiratory events, and reduce antibiotic use in infants’ (2)

There is also some research suggesting that getting enough fibre during pregnancy can even potentially reduce the chances of a baby developing autoimmune conditions like Celiac disease.

So far, so good….

At this stage, we don’t yet really know enough about the details and specifics (which prebiotic impacts which bacteria for example), but we know they have a potentially powerful impact. ‘Different prebiotics will stimulate the growth of different indigenous gut bacteria. Prebiotics have enormous potential for modifying the gut microbiota, but these modifications occur at the level of individual strains and species and are not easily predicted’ (3)

So once again, it is relatively early days in our understanding. On the whole though, feeding the bacteria we do have seems like a good idea, particularly as diversity within our gut microbiome is key – especially when we are growing a healthy baby.

So, where can I find prebiotics?

According to a paper by Markowiak and Slizewska looking at the effects of probiotics and prebiotics on health site potential, sources include:

  • tomatoes
  • artichokes
  • bananas
  • asparagus
  • berries
  • garlic
  • onions
  • chicory
  • green vegetables
  • legumes
  • lentils
  • oats
  • linseed
  • barley
  • wheat

Once again, research is relatively nascent in this area, but fibre and prebiotics are generally, at this stage, at least recognised as a safe, sensible way to boost and support your gut health and eating these foods is safe while you’re pregnant. Get involved. 

  1. SLAVIN J: Fibre and prebiotics: Mechanisms and Health Benefits: Nutrients. 2013 Apr: 5(4): 1417-1435

  2. SLAVIN J: Fibre and prebiotics: Mechanisms and Health Benefits: Nutrients. 2013 Apr: 5(4): 1417-1435

  3. MARKOWIAK P, SLIZEWSKA K: Effects of Probiotics, Prebiotics and Synbiotics on Human Health. Nutrients: 2017 Sep: 9(9): 1021

  4. MARKOWIAK P, SLIZEWSKA K: Effects of Probiotics, Prebiotics and Synbiotics on Human Health. Nutrients: 2017 Sep: 9(9): 1021


This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.