Our gut naturally contains trillions of bacteria, in fact, 1 kgs worth, which is the same weight as a bag of potatoes. This bacteria can play a key role in keeping us healthy and we've begun to understand the different health benefits that these bacteria actually provide us with.
Commonly found in fermented foods such as yoghurt and kefir, and even in capsule and powder form.
There are 2 keys ways that probiotics may work:
They compete for space and food with harmful bacteria, kicking out harmful bacteria from our gut.
Probiotics also stimulate our own immune system to help fight infections better.
Why supplement?Our gut bacteria can become compromised due to taking antibiotics, ageing, stress, sterile environments, food poisoning, low fibre diets and even gut conditions including IBS. Whilst it’s not possible to define with confidence what exactly a healthy profile of gut bacteria looks like, broad patterns are in fact emerging. More diversity is likely to be better because a diverse ecosystem is generally more resilient. Therefore supplementing with probiotics may help to increase this diversity, however, there are a few caveats to consider before purchasing a probiotic.
What should we look for when choosing a probiotic?In order to be effective, probiotics need to influence the balance of our gut bacteria. This means that bacteria must be able to survive their passage through the acidic stomach, and survival rates can vary between strains. Look out for probiotics on the market, which emphasise their effective delivery methods and those that guarantee the amount present in each pill up until the expiration date. It is also important to think about taking probiotics regularly and in a sufficient dose to allow the probiotic to exert a health effect.
Who may benefit from taking probiotics?Probiotics are an extremely complex topic and seem to work in a very strain-specific manner. And whilst we don’t all need to take probiotics, there have been some conditions where they have been researched to have beneficial effects...
ImmunityInteresting review studies have shown that taking probiotics can make colds last for shorter lengths of time. 1
EczemaResearch suggests that when probiotics are taken by breastfeeding mothers and/or their young children, there was a reduction in risk of eczema in children. 2
Mood & mental healthDid you know that 90% of serotonin is located within the gut and research suggests that our gut bacteria may influence production? Whilst this is an exciting area, more research is needed to determine probiotics’ efficacy for managing depressive symptoms.
Lactose intoleranceProbiotics may help with those who are lactose intolerant. Some studies have shown that certain strains my help to increase tolerance. 3
IBSBetween 3-25% of the population complain of IBS symptoms and probiotics are currently under study with promising results. However, we need more studies to find out which strains are the most effective, as well as to ensure there is no placebo effect. 4
DiarrhoeaInterestingly the use of probiotics in the prevention and treatment of diarrhoea has a good science-base for some probiotic strains. The strains S. boulardii and L.rhamnosus GG have been shown to cut the risk of antibiotic associated-diarrhea by more than half.
ConstipationStudies are limited when it comes to constipation, however evidence suggest that supplementing with L. casei rhamnosus Lcr35 and L. casei Shirota seems promising, so it’s worth encouraging sufferers to try products containing these probiotics strains.
1. Hao, Q., Dong, B. R. & Wu, T. (2015). Probiotics for preventing acute upper respiratory tract infections. The Cochrane database of systematic reviews - Journal Article,2, CD006895.
2. Cuello-Garcia, C. A. M. D., Brożek, J. L. M. D. P., Fiocchi, A. M. D., Pawankar, R. M. D., Yepes-Nuñez, J. J. M. D. M., Terracciano, L. M. D., Gandhi, S. B., Agarwal, A. B., Zhang, Y. M. D. & Schünemann, H. J. M. D. M. P. (2015). Probiotics for the prevention of allergy: A systematic review and meta-analysis of randomized controlled trials. Journal of Allergy and Clinical Immunology, The,136(4), 952-961.
3. Sanders, M. E. (2000). Considerations for use of probiotic bacteria to modulate human health. The Journal of nutrition,130(2S Suppl), 384S.
4. Saez-Lara, M. J., Gomez-Llorente, C., Plaza-Diaz, J. & Gil, A. (2015). The Role of Probiotic Lactic Acid Bacteria and Bifidobacteria in the Prevention and Treatment of Inflammatory Bowel Disease and Other Related Diseases: A Systematic Review of Randomized Human Clinical Trials. BioMed Research International,2015, 1-15.
Lily Soutter BSc (hons) Human Nutrition, Dip ION