Dr Kate Stephens
PhD Food and Microbial Sciences; Gut Microbiology (University of Reading), BSc Medical Microbiology
“Research”- it’s a big umbrella word that encompasses so many different types and qualities. It’s not just for the scientists or health care professionals to understand. We can all give it a go.
Why do we want research? Why is it important? Well, we want to know the product we buy is likely to work, and research may give this indication. However, so many products claim to be ‘researched’ but what does this even mean? Is it all the same? In short, the answer is no! To learn more about how to find reliable information about probiotics, read our article: Researching probiotics online: How to identify quality content.
There are different types of research, some are stronger than others. This can be seen below in the pyramid.
This pyramid shows the different types of research and how strong they are. Working from the bottom up:
‘In vitro’ test tubes: the basic ‘lab’ tests- these might test the probiotic for basic qualities such as inhibiting the growth of nasty bugs or checking survival in a range of acidities (to mimic the stomach acid). These trials give a slight indication the probiotic may be beneficial and ensure the probiotic can reach the gut alive.
Expert opinions: Opinions of experts in the field are invaluable. Experts see probiotic studies on a daily basis and can easily spot weaknesses/strengths in probiotics or research topics.
Controlled clinical trials: Trials conducted in humans, these trials give you a good idea if and how well a probiotic may work in the human body (i.e. in yourself). Controlled, blinded and randomised trials all help to reduce the risk of chance or bias results. These trials give a good indication the probiotic may work for you- ensure the strain has been trialled in this way for your health condition.
Meta-analysis: This type of trial can be quite rare. These trials look at all the controlled clinical trials for a particular health condition. They assess the quality of each trial and combine all results together. For example, a meta- analysis might be on a probiotic strain in antibiotic associated diarrhoea (AAD). The researchers will screen and analyse the strongest trials on AAD using that strain and pool results. These trials give very strong results as they can include thousands of individuals.
Ideally you want to focus on the controlled clinical trials, known as ‘the gold standard’. A high quality, well researched probiotic supplement should have these to back them up. If you know the strain of the probiotic, you can look at the research for yourself by typing into a search engine such as google. You could also ask the probiotic brand you are interested in, see if they will share any gold standard trials with you.
In addition to gold standard trials, you could also look at:
Number of people: The more the merrier in this case! The more people it’s trialled in, the greater chance you may see results. The probiotic industry does not have the financial backing of the pharmaceutical industry, so it’s always hard to mimic the number of people in their trials. Ideally look for a trial with over 50 participants.
Published: When a clinical trial becomes available online or in a scientific journal, this means its been ‘published’. In order to be published, the trial gets scrutinized by a panel of experts and they assess how well the study has been designed and if conclusions are valid. (Note: some journals are more critical than others, so published results don’t always mean they are 100% valid)
Dosage: A sneaky one to keep an eye out for! A clinical trial will always tell you the dosage of the probiotic used e.g. 1 billion or 10 billion. You might see the trial had good results at 10 billion but in the product there’s only 2 billion. If this is the case, you can’t really rely on the clinical trial data- it may be that 10 billion of that strain is needed.
There are times, even with all the right types of research, a probiotic may give you the beneficial results you were after. If this is the case, do not worry. Our bodies are so individual to us, it might be that you need to try a different probiotic strain. After all, even in the pharmaceutical sector, they never see 100% success rates and often trial and error different drugs until the right one is found for that individual.
If in doubt about research, always check the reviews on the probiotic product website but also on independent review sites such as Trustpilot.
Research is not all equal
Controlled clinical trials i.e. the gold standards are what you should look out for