Welcome to Part 2 of my ongoing article series "The Four P's of Microbiome health". Part 1 introduced the series by covering the topic of Probiotics, which has a high level of awareness in the general public. Part 2, which is this article, introduces the topic of Prebiotics.
Prebiotics, not to be confused with probiotics, are special types of fibre that are simply "food" for bacteria - they remain undigested so that bacteria can feed on them. Bacteria, as with all living organisms, require sustenance in order to survive and thrive. An accurate definition of a prebiotic is that it is a selectively fermented substrate that enhances the health of the host (in this case, a human). This means that prebiotics are different to non-prebiotic dietary fibres because they have a selective effect, where consistent changes in the level of specific bacterial species can be seen after taking that prebiotic.
Some of the benefits of specific prebiotics include:
- improved stool consistency and regularity
- decrease in the levels of candida
- reduction in bloating
- improvement in sleep quality
- enhancement of immune system
- reduction in anxiety
- improvement in insulin sensitivity
- reduction in inflammatory markers - relevant to so many states of illness including depression, obesity and Type 2 diabetes
Please note that some of these benefits have less rigorous evidence than others, since this area of health science is still developing every day.
Importantly, prebiotics feed both our indigenous gut bacteria and also any probiotics taken in as a supplement. Since probiotic products contain only a limited number of bacterial strains, prebiotic foods are an essential component of a microbiome-supportive routine that promotes diversity. For this reason, I believe that prebiotics may be more important than probiotics. They are essential to restoring and diversifying the microbiome, whereas probiotics are quite limited in their range when it comes to the sheer number of bacterial species found in the gut. Many prebiotic products are also quite cost-effective, which is always a good thing!
One of the key ways that prebiotics exert their effect is via their fermentation by the bacteria, resulting in the production of short chain fatty acids (SCFAs), including the most well known which is butyrate. SCFAs are molecular messengers that have both a local beneficial effect in the gastrointestinal tract and are also absorbed via the intestinal lumen, from where they can exert systemic anti-inflammatory effects.
Prebiotics may be purchased as a standalone supplement or they are naturally found in many foods. As a supplement, they are often in powdered form and are easily incorporated in to porridge or a smoothie. One thing I really like about prebiotics is that they tend to be very affordable – this is not the case with all of them however – Bimuno (a galacto-oligosaccharide/GOS supplement) and arabinogalactans both tend to be on the more expensive side, but most others are affordable.
Prebiotics support specific species of bacteria, so it’s important to choose the appropriate ones for your individual situation if you have a specific health complaint you want to address, or if you have some stool test results that you want to address. For more general health promotion, combining more than one is a good strategy as it supports overall microbiome diversity. See the below section "What you can do" for more information.
Some prebiotics are contraindicated (or not recommended) in certain situations – eg. inulin may worsen cases of IBS and/or SIBO (small intestinal bacterial overgrowth) so that one is best avoided in that situation.
Colonic foods, such as psyllium and flax, are similar to prebiotics, although their effects tend to be less specific in terms of which bacterial species they promote the growth of. This is why they are not referred to as prebiotics.
Here is a list of some easily obtainable prebiotic supplements and foods - it is not a definitive list, but it is varied enough to promote a diverse microbiome and to give you plenty of ideas to try.
- Fructooligosaccharides (FOS) - with three sub-types including inulin
- Partially hydrolyzed guar gum (PHGG) - eg. SunFiber
- Lactulose syrup eg. Actilax
- Green Banana flour and raw potato starch*
- Bimuno (Galacto-oligosaccharides/GOS)
- Xylooligosaccharides (XOS)
- Larch arabinogalactans
- Acacia fibre
*I tend not to recommend raw potato starch as it is processed with sulfurous acid which can result in smelly flatulence for some people
- Resistant starch foods: Cooked and cooled white potato and white rice; tigernuts; raw green banana flour; green-tipped bananas; green plantains
- Dandelion, chicory, onions, leeks, garlic
- Gluten-free oats, oat bran and buckwheat
- Raw nuts and seeds
- Slippery Elm
- Psyllium Seed and Husk (seed has a more powerful effect on butyrate levels)
- Flaxseed meal
- Pomegranate husk
What you can do
Include different sources of prebiotic fibres and colonic foods regularly in your diet. Have fun experimenting with different foods, but do experiment gradually, especially if you have a sensitive gut.
When it comes to prebiotic supplements, I suggest trying one new item at a time and in small amounts initially as there are often temporary side effects such as gas and bloating as the microbiome adjusts.
If you have a specific health complaint, I recommend you consult a qualified health practitioner (such as myself) to guide you with a personalised program to support your microbiome with the appropriate prebiotics. Not all prebiotics are suitable for everyone as mentioned above.
If you're ready to get cracking in the quest to improve your microbiome and general health, here are some of my very tasty recipes to get you on your way!
- Refried Black Beans
- Smoky Hummus
- Mango Lassi Protein Pudding
- Honey Chai Granola
- Japanese Curried Egg and Potato Salad
Work with Me
If you'd like help restoring or optimising your microbiome, find out how I can work with you.
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