Neil McIntosh, Sporting Gun’s gundog health expert, asks the question: do probiotics actually work?
Dogs begin life with a sterile intestinal system, but very quickly this becomes colonised by bacteria that collectively form the ‘microbiome’; an army of microorganisms that are essential for health and life, as they protect against pathogenic bacteria and are involved in digestion, the immune system and vitamin production.
The canine small intestine can contain up to 700 different strains of bacteria, while the large bowel may be colonised by up to 5,000. Although each individual has a unique microbiome, a relatively small number of common bacterial groups are generally involved. The theory is that changes in the normal microbiome can cause gastrointestinal disease.
What are probiotics?
Indeed! What are they? They are supposed to be products that contain ‘healthy bacteria’ in a form that makes them supportive of the normal microbiome. But are they? Probiotics have been under scrutiny in the EU since 2007 and few products have been approved because of a general lack of proof of efficacy. Since the term ‘probiotic’ implies a health benefit, its use has been banned by the EU since 2012.
In the US, probiotics are classed as nutritional supplements (they help normal function as opposed to treating or preventing disease), so they undergo little regulation. Numerous studies have found poor packaging, misspelling of the names of microorganisms, misleading claims for numbers and types of bacteria and a lack of evidence for shelf-life viability.
To sum up, probiotics must be:
- Purchased from a reputable source
- Based on product efficacy research
- Safe (no viruses or transmissible bacteria)
- Able to survive passage through the gut
- Stable during storage
- Labelled with actual microbial content
- Possess a guaranteed analysis of shelf-life viability
- Proven to actually work
When should they be used?
- Probiotics might be indicated for:
- Gastrointestinal infection
- Stress-related tummy upset
- Dietary change
- Ingestion of contaminated/decayed foodstuffs
- Antibiotic use
- Other medications
One interesting fact is that Enterococcus faecium is not killed by the antibiotic metronidazole, but it is by amoxicillin. Its use, therefore, may need to be ‘timed’ according to the antibiotic treatment and this sort of anomaly might explain the varied response to probiotic use.
Do they work?
Well, maybe. Some people swear by them. But then they might also believe in Santa Claus. However, studies in humans have indicated the potential for treating gastrointestinal disease, while research in humans, dogs and cats has shown that individuals suffering from acute diarrhoea often have a disturbed microbiome. It seems that probiotics may help in some disorders, but not in others. Certainly, they have been used successfully in humans to prevent antibiotic-associated diarrhoea and the inflammatory bowel disease pouchitis.
They have been helpful in the treatment of some infectious causes of diarrhoea and irritable bowel syndrome. There is not a huge amount of veterinary research but, again, quality probiotics have been proven to help with antibiotic-associated diarrhoea, stress-related diarrhoea and gastrointestinal upset due to dietary change.
A 2009 Irish study, conducted by R L Kelley et al, showed that supplementation with a specific strain of bacteria called Bifidobacterium animalis reduced the duration of diarrhoea from seven to four days and it reduced the requirement for antibiotic treatment by 10% compared to a placebo. The bottom line for me is that you should choose a probiotic that has some proper clinical research to support its use, and not just a list of fantastical testimonials.
The good guys?
At the risk of becoming more of an elocution lesson than a veterinary article, the bacteria to look out for on the label include:
- Bifidobacterium lactis
- Bifidobacterium breve
- Bifidobacterium animalis
- Lactobacillus acidophilus
- Enterococcus faecium
- Lactobacillus casei
How do they work?
Nobody really knows for sure but potentially they might:
- Compete for binding sites with pathogens in the gut
- Improve the integrity of the intestinal lining
- Block toxins
- Stimulate the immune system