The therapeutic use of probiotics in cases of diarrhoea

The therapeutic use of probiotics in cases of diarrhoea, by Sarah Swindlehurst-Mulliner

It is said and researched that probiotics can help certain types of diarrhoea, namely travelers diarrhoea, antibiotic associated diarrhoea, rotavirus/novo virus – especially in children, colitis, irritable bowel syndrome, inflammatory bowel syndrome, diverticular disease, and also lactose intolerance. Stress symptoms which sometimes include diarrhoea, can also be helped with the use of probiotics.

The large intestine forms the major reservoir of micro-organisms in the body. Friendly bacteria in the colon keep unfriendly strains in check, partly by using carbohydrate to create lactic acid; this helps maintain the pH of the intestinal environment, as well as producing on-site hydrogen peroxide. Friendly bacteria drive down the pH of the gut, creating an inhospitable environment for unfriendly strains.

As mentioned, our intestines host an abundance of friendly gut flora and bacteria essential to maintaining our health. However when ‘unfriendly’ bacteria’s become abundant in our gut, the microbes can be thrown off balance, and toxins are produced which in turn pollute our bowels. Too much toxicity can put our liver under strain and the toxins are then poured into the bile, and returned to the colon, creating a vicious cycle. In a ‘normal’ healthy body, the ‘friendly’ bacteria help to keep the ‘unfriendly’ ones at reduced levels and a low toxicity. Circumstances leading to a person to have diarrhoea can be caused by infections, antibiotics or an unhealthy lifestyle and an inadequate nutritional intake. During digestion the food mixes with water and the digestive juices to create the watery substance chyme. When it reaches the large intestine the liquid is absorbed by the colon and well formed stools are created. However if the gut is inflamed or damaged by pathogens and ‘unfriendly’ bacteria the liquid cannot be absorbed and so creates the diarrhoea [1].

The uses of probiotics have been linked to bringing balance back into the gut – ‘probiotics’ meaning ‘for life’. Probiotics is a specific type of bacteria or yeast that has been identified as a specific genus, species and strain. Each type of probiotic has specific effects on the human body and is able to compete with disease causing bacteria and reproduce in the intestinal tract for a week or two [2].

These are seen as nutritional, live microbial supplements positively affecting and enhancing the microbial balance in the gut by their ability to adhere to mucosal cells, and creating harmony in our bodies. One of the most common strains of probiotic is Lactobacilli or Bifidobacteria, both of which naturally inhabit the human body. In particular, Lactobacillus acidophilus and Bifidobacterium lactis have been identified as the principal adhesion strains of lactic acid bacteria (although Bifidobacterium is not usually classified as a lactic acid bacteria) . inhibiting the growth of pathogens by fighting for the receptor sites on epithelial cells, and for nutrients. Higher in the tract (small intestine) Lactobacillus thrive due to higher concentration of oxygen while Bifidobacteria thrive in low oxygen concentrations (colon). Lactobacillus acidophilus and Lactobacillus bulgaricus have been shown to be effective in lab testing against these pathogens: Bacillius subtilis, Clostridium Botulinum, Clostridium perfringens, Escherichia coli, Proteus mirabilis, Salmonella enteridis, Salmonella typhimurium, Shigella dysenteriae, Shigella paradysenteriae, Staphylococcus aureus, and Staphylococcus faecalis [3].

Bifidobacteria infantis has been said to protect against bacteria that promote inflammatory bowel disease, helpful to alleviate the symptoms of IBS and also has antitumor properties in test research [4].

Probiotics strengthen the non-immunological defences of the GI tract, production of antimicrobial substances [5], stimulating mucus secretion, reinforcing gut barrier function, improving gut motility, stimulating cytokine and natural killer cell production (cytokines and natural killer cells are produced by the immune system in response to infection), enhancing the phagocytic capacity of cells and macrophages, and enhancing specific antibody responses to pathogens. Pathogenic microbes include E.coli, yeasts (particularly Candida albicans), staphylococci (particularly S. aureus) and streptococci (see mention of Lactobacillus acidophilus and Lactobacillus bulgaricus in previous paragraph).

Antibiotic associated diarrhoea is caused due to the antibiotic(s) not only killing the bacteria which caused the person’s symptoms but they also kill the ‘good’ bacteria in the gut. Antibiotics disrupt the balance of healthy gut bacteria which then allows for harmful bacteria to flourish. Some symptoms include indigestion, discomfort and excessive flatulence, as well as severe diarrhoea. The pathogenic bacteria Clostridium difficile thrives in the gut after a person has taken antibiotics and causes the inflammation that leads to diarrhoea. Colitis is said to stem from this pathogen. Scientists have studied that Saccharomyces boulardii (S. boulardii) is one of the most beneficial probiotic (a friendly yeast) to fight against this type of bacteria [6] as it is a powerful probiotic and yeast that can help maintain the natural flora in the intestines, as is Lactobacillus GG [7] and is recommended to remedy acute diarrhoea, IBS, inflammatory bowel disease and Crohn’s disease.

There is evidence thatSaccharomyces boulardii might also prevent diarrhoea in day-care centres [7]Lactobacillus rhamnosus GGwas associated with reduced diarrheal duration and severity, more evident in case of childhood Rotavirus diarrhoea. Similar, although weaker, evidence was obtained with S. boulardii. Both strains are included in evidence-based recommendations for gastroenteritis management in children. LGG and S. boulardii are the strains most widely tested and also are the most effective in many cases of infection, pathogens and diahorrea symptoms. The efficacy of LGG as an adjunctive treatment of diarrhoea is now considered conclusive [7].

Probiotics has been recommended also in the prevention of traveller’s diarrhoea, and as a remedy. Travelling in foreign countries is a risk factor for infectious gastroenteritis. There is some evidence of a protective effect by S. boulardii and by mixture of Lactobacillus acidophilus and Bifidobacterium bifidum [8]

In the case of lactose intolerance (known as lactose malabsorption and  is associated with the inability to break down lactose into its constituents, glucose and galactose, due to low levels of lactase enzyme activity), studies have shown that people with lactose intolerance tolerated the lactose in yogurt better than the same amount of lactose in milk. The assumption was that the presence of lactase producing bacteria in the yogurt, especially Lactobacillus acidophilus, contributed to the digestion and absorption of lactose (5-6, 13). It was also found that the presence of Lactobacillus bulgaricus and Streptococcus thermophilus alleviate lactose intolerance through their ability to produce lactase enzyme [9].

Of note, another way of boosting the healthy bacteria is by eating foods that contain FOS (fructo-oligosaccharides) such as bananas, onions, soybeans, or taking a probiotic supplement which includes it (also known as a ‘pre-biotic) , helps to ‘feed’ the good bacteria (the probiotics) and promote the good guys and less of the bad guys [10] FOS promotes rapid multiplications of the probiotics, which might mean less probiotics need be taken. Also choosing a probiotic that is enteric-coated is ideal as this allows the supplement to survive the acid of the stomach and head straight for the intestines intact with all the probiotics which would otherwise have been destroyed.

So to conclude, probiotics that may or may not include a ‘prebiotic’ can be very beneficial for balancing the intestinal health and putting in the ‘good’ bacteria so that it can combat and decrease the ‘bad’ bacteria and any pathogens. Certain probiotics such as Lactobacilli, Bifidobacteria, and Saccharomyces boulardiias have shown to be amongst the most beneficial of probiotics in tackling the symptoms of diahorrea with a good success rate, and more research is being constantly being sought and found into their extremely useful role in our health and wellbeing.



[2] Digestive Wellness, 4th Edition, Elizabeth Lipski, P56

[3] Digestive Wellness, 4th Edition, Elizabeth Lipski, P57

[4] Digestive Wellness, 4th Edition, Elizabeth Lipski, P58

[5] Gill, H., Probiotics to enhance anti-infective defences in the gastrointestinal tract. Best Practice & Research Clinical Gastroenterology, 2003. 17(5): p. 755-773.



[8]McFarland LV. Meta-analysis of probiotics for the prevention of traveler’;s diarrhea. Travel Med Infect Dis 2007; 5:97-105.


[10] New Optimum Nutirtion Bible, 2004, Patrick Holford, p.159