There are many different types of research – from simple research in a test tube or petri dish in a lab (known as in-vitro research) to more comprehensive research in a clinic or hospital where people are given the probiotic or a placebo and their symptoms are measured over a few weeks or months (known as clinical research).
One of the easiest ways of finding out if a probiotic supplement has been researched is to look at the strains it contains. For example if the ingredients section on the packaging of the probiotic supplement lists L. acidophilus NCFM® you can type this strain name into a search engine, or a database of scientific research such as PubMed, to see what research publications are available. For example ‘NCFM’ in PubMed yields over 100 publications. It can be difficult to find information about research on probiotic supplements where the strains are not included on the packaging e.g. ‘L. acidophilus’ in the ingredients list could mean L. acidophilus NCFM® or L. acidophilus Rosell-52, and these strains have completely different research behind them1,2. A probiotic may even contain a strain of L. acidophilus which has no research. So a key marker of transparency with regards to research is if the strain names are included in the ingredients list.
Whilst in-vitro evidence is important, and can be significant to demonstrate factors like survival at different pH levels, and even ability to adhere to epithelial cells; generally speaking clinical trials (where products are tested on human beings, for certain benefits) provide better evidence to demonstrate a probiotic’s effect on the body. A probiotic may have seen many ‘studies’, yet these could refer to in-vitro or animal studies, rather than clinical trials. What’s more, clinical trials have different standards - some have a high number of participants, others only tens. Some clinical trials are double-blinded and placebo controlled, and others are not. It is important, that when we hear words such as ‘best studied’ or ‘proven’, we question what this really means.
A probiotic range with documented clinical trials.
What is a placebo-controlled study?
This myth has been busted by Megan Crowch, BSc (Hons) Physiology, Herbal Medicine Diploma (IRH practicing member).