1. What is your gut microbiome?
Your gut microbiome is made of up a 100 trillion microorganisms that live in your digestive tract – collectively these weigh up to 2kg. These bacteria break down food and toxins, make vitamins and interact with our immune system, among many other things.
2. What is gut dysbiosis?
Gut dysbiosis is an imbalance in the bacteria with beneficial effects and those with harmful effects in the gastrointestinal tract. Common symptoms of dysbiosis are diarrhoea, constipation, nausea, bloating, fatigue, anxiety and depression among others.
3. Why does gut dysbiosis occur
An imbalance in your gut microbiome can be caused by a number of factors such asa change in diet, increased alcohol intake (more than two alcoholic beverages a day), new medications such as antibiotics, increased levels of stress and/or anxiety.
4. What are probiotics?
Probiotics are, live microorganisms that confer a health benefit when delivered in adequate amounts to the host. This supply of beneficial bacterial cultures can support and balance the gut microbiome.
5. What is the difference between prebiotics and probiotics?
Probiotics are related to, but not the same as prebiotics.
Prebiotics are non-digestible fibres that pass through the gastrointestinal tract to stimulate the growth and activity of non- pathogenic bacteria in the large intestine. Prebiotics can be found naturally in fermented foods such as kombucha, sauerkraut, kimchi and kefir.
6. Which has greater benefit, supplementing with a prebiotic or a probiotic?
Prebiotics on their own have been found to have little benefit, however when used in conjunction with probiotics they may make them more effective. You can find this prebiotic and probiotic combination in some supplements. Furthermore, some foods are natural synbiotics (contain both prebiotics and probiotics) these include cheese and kefir.
7. How many strains does a probiotic supplement need to have to be effective?
Multi-strain probiotic supplements are believed to be the most beneficial for balancing and maintaining the gut microbiome.However, the supplement needs to have been tested to ensure all the strains survive together until consumption. As a result of this uncertainty some 10 strain supplements may not be as beneficial as high quality 5-6 strain supplements.
8. Is there a risk of becoming dependent on or addicted to probiotics?
There is no known risk of becoming dependent on probiotics and they are seen as safe for long- term use.Dependency when refers to a situation where the individual becomes reliant on the food supplement and has to consume larger and larger amounts in order to function normally. This can occur when taking vitamin or digestive enzyme supplements, due to the body no longer producing its own stores. However, the body does not produce its own probiotics in adulthood, since the gut microbiome begins formation at a very young age. As a result, we cannot become dependent on probiotic supplementation.
1. Can probiotics help with weight loss?
Studies have highlighted the relationship between gut flora and weight. Mouse studies have shown that certain species of bacteria in the gut can trigger weight gain and other species seem to encourage weight loss. This was demonstrated by researchers removing gut microorganisms from an overweight mouse and transplanting them in to a thin mouse and vice versa. This swap resulted in a changed gut environment in each mouse with the thin mouse gaining weight and the fat mouse losing it(1). However, we are yet to understand which bacterial strains influence weight loss and how.
Another aspect to weight loss in the short term is bloating. Clinical trials using many different strains of probiotics have studied their effect on bloating and distension of the abdomen. A 2008 study involving 41 female participants who were given a fermented dairy product containing Bifidobacterium lactis or a placebo for 4 weeks, saw a significant reduction in bloating severity and frequency in the probiotic group(3). However more research needs to be done before we know exactly which strains of bacteria may be able to provide lasting weight loss.
- Turnbaugh P, Ley RE, Mahowald MA, Magrini V, Mardis ER, Gordon JI., 'An obesity-associated gut microbiome with increased capacity for energy harvest.' Nature. 2006 Dec 21;444(7122):1027-31.
- Yadav H, Lee JH, Lloyd J, Walter P, Rane SG, 'Beneficial metabolic effects of a probiotic via butyrate-induced GLP-1 hormone secretion.'J Biol Chem, 288(35): 25088-97
- A. Agrawal, L.A. Houghton, J. Morris, S. Jakob, First published 17 September 2008, 'The effects of a fermented milk product containing Bifidobacterium lactis DN-173 010 on abdominal distension and gastrointestinal transit in irritable bowel syndrome with constipation' Aliment Pharmacol Ther, 29(1): 104-14
2. Can probiotics help with infant colic?
Colic is a temporary self-limited condition, which occurs within the first few months of life. It is characterized by inconsolable crying of without a known cause(1). Despite appearing benign nature, some research has linked colic in infancy with complications in later life such as sleeping disorders and gastrointestinal issues(2).
A study looking at the stools of infants in their first 100 days of life in order determine the composition of their gut flora, found that babies who suffered from colic had reduced bacterial diversity in their gut microbiome. When looking in depth, the babies who had colic were found to have lower levels of the beneficial bacterial species Lactobacilli and Bifidobacteria which may result in increased inflammation(3).Further studies have shown that probiotics may play a preventative role in the development of colic. A clinical study took place between 2010 and 2012 where children received beneficial bacteria suspended in oil five times a day for three months. Results claimed that those who received the probiotic strain had better stool frequency and spent half as long crying each day as the placebo group(4).
Since babies with colic have been found to have differential gut flora to healthy babies3 the modulation in the microbiome seen with these strains provides new avenues for the use of easily available probiotic supplements to treat or prevent colic.
- Wake M, Morton-Allen E, Poulakis. Prevalence, stability, and outcomes of cry-fuss and sleep problems in the first 2 years of life: prospective community-based study. Pediatrics. 2006 Mar; 117(3):836-42.
- Savino F, Castagno E, Bretto R et al. A prospective 10‐year study on children who had severe infantile colic. Acta Paediatr.2005; 94: 129–32.
- de Weerth et al. ‘Intestinal microbiota of infants with colic: development and specific signatures’, Paediatrics, 2013
- Indrio F, Di Mauro A, Riezzo G et al.'Prophylactic Use of a Probiotic in the Prevention of Colic, Regurgitation, and Functional Constipation: A Randomized Clinical Trial'. JAMA Pediatr. 2014.
3. Can probiotics help with allergies?
Our gastrointestinal tract houses 70% of the body’s immune cells(3). Therefore, our gut microbiome is able to interact with the immune system and our immune response. When gut health is poor or undeveloped the lack of friendly flora means harmful bacteria can populate the gut with detrimental effect. This may result in changes to the integrity of the gut lining and hyperpermeability, with undigested food particles entering the bloodstream and triggering an inflammatory response and allergy symptoms.
Research has shown benefit in giving probiotics to children and adults with allergies, as this is believed to help the gut flora to flourish. In one case, infants with cow’s milk allergy were seen to have an improved tolerance to cow’s milk when it was given in conjunction with a probiotic supplement(4).
- Henry Ford Health System. Babies born by C-section at risk of developing allergies. ScienceDaily. ScienceDaily, 25 February 2013.
- Pawankar R, Canonica GW, ST Holgate. The WAO White Book on Allergy 2013
- Montalban-Arques A et al. Selective Manipulation of the Gut Microbiota Improves Immune Status in Vertebrates, Frontiers in Immunology. 2013. 9;6:512. Indrio F, Di Mauro A, Riezzo G et al.'Prophylactic Use of a Probiotic in the Prevention of Colic, Regurgitation, and Functional Constipation: A Randomized Clinical Trial'. JAMA Pediatr. 2014.
- Canani and Costanzo, Gut Microbiota as Potential Therapeutic Target for the Treatment of Cow’s Milk Allergy, Nutrients. 2013; 5(3): 651–662.
4. Can probiotics help Alzheimer’s sufferers?
The quantity of beneficial bacteria in our gut is known to decrease as we age(1). Likewise, with age it is not unusual to experience forgetfulness and issues carrying out activities of daily living. One diagnosis for this set of symptoms is Alzheimer’s disease. Studies in recent years have looked at the influence gut flora may have on the brain, through a relationship coined ‘the gut brain axis’.
A 2016 study(2) carried out at the Kashan University of Medical sciences focused on the association between gut flora and Alzheimer’s disease. This trial involving 52 patients with Alzheimer’s and an average age of 80, ran over a 12-week period. The patients either received milk containing bacterial cultures or normal dairy milk on a daily basis. The patients’ cognitive function was measured before and after the 12-week period using a Mini-Mental State Examination (MMSE), a questionnaire used commonly to measure cognitive impairment. Following the 12-week period this study recorded an MMSE score improvement of 27.9% in those who had been provided with the friendly bacteria.
One strand of studies suggests the association may be due to a reduction in Lactobacillus and Bifidobacterium quantities in the gut with age(3). These bacteria are involved in the production of the neurotransmitter GABA. GABA is a major inhibitory neurotransmitter in the central nervous system, disruption of this system may contribute to cognitive impairment(4,5).
Although Alzheimer’s is not believed to be curable, studies like this do provide a basis for longer and larger trials investigating the effect of live culture supplementation on the progression of Alzheimer’s disease.
- Ouwehand AC. et al. Influence of a combination of L. acidophilus NCFM® and lactitol on healthy elderly: intestinal and immune parameters. J Nutr. 2009. 101(3):367-75.
- Akbari Elmira et al. Effect of Probiotic Supplementation on Cognitive Function and Metabolic Status in Alzheimer's Disease: A Randomized, Double-Blind and Controlled Trial. Frontiers in Aging Neuroscience.2016
- Solas, M., Puerta, E., and Ramirez, M.J. Treatment options in Alzheimer’s disease: the GABA story. Curr Pharm Des .2015. 21, 4960–4971.
- Lanctot, K.L. Herrmann, N.Mazzotta, P. GABAergic function in Alzheimer’s disease: evidence for dysfunction and potential as a therapeutic target for the treatment of behavioural and psychological symptoms of dementia. Can J Psychiat 2004. 49, 439–453.
5. Can probiotics improve mental health
The term ‘psychobiotic’ has been defined by the Society of Biological Psychiatry as “a live organism that when consumed in adequate amounts produces health benefits in patients suffering from psychiatric illness”(3). In essence they are probiotic strains believed to have some physiological benefit.
Unlike most medical treatments these live cultures are believed to have many different modes of action when it comes to improving mood(3). They are thought to activate neural pathways between the gut and the brain, reduce systemic inflammation and reduce pathogenic bacteria in the gut. Furthermore, these probiotic strains have been found to directly produce the mood modulating neurotransmitters GABA and serotonin to influence how we feel.
Although probiotics are not currently recognised as a treatment for mental health issues, some individuals may find benefit from combining live culture supplementation with their current prescription.
- Generalised anxiety disorder in adults- https://www.nhs.uk/conditions/generalised-anxiety-disorder/
- Low mood and depression- https://www.nhs.uk/conditions/stress-anxiety-depression/low-mood-and-depression/
- Eva M. Fermented foods, microbiota, and mental health: ancient practiice meets nutritional psychiatry'. Selhub. Journal of Physiological Anthropology, 2014