Do probiotics reach your gut alive?
Probiotics can be a potent tool to heal your gut. They usually come in the form of pills or capsules, but can also be found in what are called “fermented foods”. Microorganisms and yeasts are used during the production of certain foods in order to obtain unique flavours and textures, but also to increase the shelf-life of the product. For instance, from your supermarket, you could get probiotics such as Lactobacillus plantarum in sauerkraut,¹ Rhizopus oligosporus in tempeh,2 Lactobacillus acidophilus and Bifidobacteria in yoghurt and kefir,3 and so on.
It is known that to provide any health benefit, probiotics need to reach the gut while still being alive. There is some evidence that suggests that dead bacteria can still evoke positive health effects,4, 5 but these dead bacteria are not considered probiotics. The best health benefits are achieved when alive bacteria can perform activities such as the production of short-chain fatty acids (SCFA),6 reduction of gut inflammation (which improves leaky gut syndrome), and protection against pathogenic bacteria,7, 8 just to mention some of them.
Several factors affect the viability of probiotics:
- Food composition (acidity, oxygen availability, the concentration of sugars, moisture content and storage temperature)9, 10
- Enzymes in your saliva
- Acidity and digestive enzymes of your stomach and upper small intestine
- Temperature and lack of oxygen in the gastrointestinal (GI) tract
- Competition with other bacteria for nutrients and space required to survive in the gut
How can bacteria survive the harsh conditions of the gut?
Probiotics found in dairy products (yoghurt and kefir) have a bigger chance of survival because the dairy reduces the effects of the stomach acid.11, 12 Similarly, enteric coat capsules are made with the purpose to protect bacteria found in probiotic supplements.13 Other manufacturers prefer to use spore-forming bacteria, such as Bacillus species (instead of living bacteria),14 since the endospores that encapsulate the strains are highly resistant to stomach acid.15 Once arriving into the gut, the spores germinate and produce living bacteria (which can be detected in faeces) that seems to inhabit the GI tract. The number of living bacteria after germination, however, varied in different studies, probably due to physiological conditions (e.g., diet) of the host.16 An example of fermented food that contains Bacillus subtilis is natto a traditional Japanese food made from fermented soybeans.
But, how can we really tell if probiotics don't die in the gut?
You can find it out in here!
Here are my top tips to maximize probiotic survival into your gut!
- If you decide to buy a probiotic in the form of capsule or pill, do not take the ones that are refrigerated, since these bacteria are “weaker”17 and this is why they need to be cold. Most of them won’t make it to the gut. Instead, chose for the spore-forming probiotics.18 As an example, check this one out: Just Thrive spore probiotic.
- Take the probiotic with a small amount of water on an empty stomach, since it’s the moment where less stomach acid is produced. The stomach will empty out faster than when there is food. You can also take the probiotic with bicarbonate of soda, an alkaline powder that will neutralize the stomach acid for some time.
- If you prefer to go for fermented foods, then the desired amount of consumption would be at least 100 g per day of yoghurt, kimchi, tempeh, kefir, kombucha or miso.19
- Eat prebiotics. These arrive at the gut undestroyed and feed the good bacteria.20 You can incorporate more of these fruits and vegetables into your diet. For example onion, garlic, asparagus, banana, chicory root, artichoke, wheat, legumes, flaxseeds, whole wheat, rye and tomatoes.21
- Be consistent. Just keep in mind that even though probiotics are transient,22, 23 science has proven its health benefits for gut health.24, 25