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Bacillus coagulans (Lactobacillus sporogenes) a probiotic ?
In Europe, Asia and the US several products are marketed with the possible probiotic bacterium Bacillus coagulans, often marketed wrongly as ‘Lactobacillus sporogenes'. Other designations of this strain in products are ‘Lactospore', ‘spore forming Lactobacillus' or ‘spore forming lactic acid bacteria'.
In several countries there has been a debate whether this is a valid bacterial name and whether the product can indeed be considered a probiotic.
This monograph aims to clear this matter.
The bacterial species, now known as B. coagulans, was isolated in 1932 by Horowitz-Walssowa and Nowotelnow (1) as Lactobacillus sporogenes and subsequently reclassified in 1939 as Bacillus coagulans. The name “ Lactobacillus sporogenes” thus has no further scientific status and should not be used in either scientific publications or consumer information.
Legally the European Food Law states that consumers may not be mislead by the producer using labeling and advertising (2), that ingredients should be indicated by their specific name (3), which is to be the legal name in the country and “ which is clear enough to let the purchaser know its true nature and distinguish it from other products with which it might be confused” (4).
The law thus states clearly that any ingredient should be labeled with its official legal name. And that the product may not be confused with other (similar) products.
Unfortunately there is no legal list of bacterial names, however, there is a list of accepted scientific names, which is widely acknowledged by the international scientific community and scientific journals as the official list of bacterial names. This list can be found at www.bacterio.cict.fr (5). Any name not listed here can thus be considered as a non-legal or non-existing name. From this it can be concluded that B. coagulans is the only official name, as L. sporogenes is not listed.
The use of the name ‘L. sporogenes' also may be confusing to consumers, as it would indicate that there are Lactobacillus species present, which is not the case. The use of ‘L. sporogenes', thus is in violation with the EU law (4).
Furthermore, as probiotic claims should be substantiated with scientific claims, a name that is not scientifically accepted should not be used. If someone would like to investigate the claims, no information will be found if a non scientifically accepted name is being used. This can be elaborated with L-ascorbic acid (Vitamin C), which may also be listed as E300 on the label (in Europe). There are plenty scientific studies with L-ascorbic acid or vitamin C, but there are no studies with E300. In this case E300 is a legally accepted synonym for L-ascorbic acid when used as a food additive (antioxidant). This means that producers can legally use E300 on the label for use as an antioxidant, but not for use as a vitamin supplement.
It is stated by some producers that the name is retained ‘in honour of the discoverers'. This may be a good idea, but to use the old name is not the proper way to do so. A well known probiotic bacterium, LGG, is also named after the discoverers and has a much more complex taxonomic history :
The strain indication GG thus clearly honours the discoverers. An alternative for ‘L. sporogenes' could thus be B. coagulans HW-N.
Another argument by some producers is that they retain the old name ‘for historical reasons'. As most bacteria have changed taxonomic position during the years, it would be most confusing as this would be made common practice. Probiotic bacteria such as Lactobacillus acidophilus or Bifidobacterium species, were originally designated Bacillus acidophilus and Bacillus bifidus respectively. All Bacillus bifidus (later also known as Lactobacillus bifidus) are now within a genus of more than 20 species…. The well known E.coli would still be Bacillus coli etc. In any case, the name L. sporogenes was in use only for 7 years, with practically no publications (and thus no historical ‘value'), whereas B. coagulans has been in use for 70 years with thousands of publications. For historical reasons, the name B. coagulans would thus be much more suitable !
Finally in several publications and in many product descriptions provided by manufacturers of products with this bacterium, it is stated that B. coagulans is not a proper Bacillus and has some characteristics in common with the genus Lactobacillus. Considering the characteristics of the species it can be stated that it indeed bears characteristics of both genera. There are as many arguments to place the species in Lactobacillus as in Bacillus. There is, however, no conclusive argument to place the strain under Lactobacillus, whereas the spore-forming capacity definitely places the strain within the genus Bacillus. By definition, the genus Lactobacillus does not form any spores (5), which makes it impossible to name the strain Lactobacillus. As there are more bacteria that make lactic acid, the fact that it produces lactic acid is not conclusive to place the strain in the genus Lactobacillus.
Therefore, unless there is a taxonomic change in the genus Bacillus, the official name remains B. coagulans.
Of the other designations ‘Lactospore' and ‘spore forming lactic acid bacteria' can be used freely in advertising, but not as an ingredient. Lactospore is a brand/market name and thus can not be a listed ingredient (6). It can be used properly when the strain is listed as B. coagulans (Lactospore). ‘Spore forming lactic acid bacteria' is a general description and the B. coagulans may be part of that group. On a label it is as valid as stating ‘Colour' or ‘Emulsifier'. The general description is correct, but not as an ingredient.
The designation ‘spore forming Lactobacillus' is definitely incorrect, as by definition Lactobacillus species do not form spores and, as stated above, this may be confusing and thus illegal. It is like saying ‘a barking cat'; some cats may look like dogs, but they do not bark.
Concluding, the name Lactobacillus sporogenes has no scientific or legal status and thus does not ‘exist' scientifically and therefore should not be used on product labels. The official name is Bacillus coagulans.
Lactobacillus species are normally considered safe for human consumption, even in large doses (Donohue). Among the genus Bacillus, however, there are many species that produce toxins, including the well known Bacillus anthracis (anthrax) and Bacillus cereus (food poisonings). B. coagulans has been implicated in human infections, but not from oral administration. B. coagulans is thus not known to be a pathogen or to produce endotoxins. B. coagulans, however, does not have a GRAS status of the FDA, nor has there been a thorough independent safety evaluation of this species (7). Bacillus species are, unlike Lactobacillus species, not considered a normal part of the intestinal microflora. They can be isolated from faeces, but only as transient species. There are no indications that Bacillus species can colonise the human gut.
To be considered a probiotic the joint FAO/WHO Expert Consultation on Evaluation of Health and Nutritional Properties of probiotics in food (2001) recognized the need for guidelines to set out a systematic approach for the evaluation of probiotics leading to the substantiation of health claim. As a consequence, a consensus panel on selection criteria for probiotics was developed in which base requirements for probiotics were stated (8,9). They include a correct identification at strain level of the microorganism, as well as in vitro tests to determine physiologic and functional health characteristic of the strain and in vivo trials to substantiate efficacy in humans or in animals (8,9).
A large review has been published in 2003 on the use of spore forming bacteria as human probiotics (7), which included B. coagulans. It was concluded that there are only very few studies in which B. coagulans was successfully used as human probiotic (see references sited in 7). This conclusion was confirmed by De Vecchi and Drago (8).
A recent search in the scientific databases Medline, Current Contents, PubMed and Food Science and Technology Abstracts (nov 2006) did not result in many new publications since 2003 on the use of B. coagulans (or L. sporogenes) in humans.
These studies included a study on the t reatment of irritable bowel syndrome in humans (10) In this study a complex product, including three bacteria (B. coagulans, L. acidophilus and S. salivarius ssp thermophilus) and several plant extracts was used. The effects were minimal and could not be attributed to either the bacteria or the other (chemical) components in the mixture (10).
Another study from 2003 showed a reduction in diarrhea in children. In this study both B. coagulans and fructo-oligosaccharides were used (11)
Another recent publication (12) shows a positive effect of B. coagulans on vaginitis, but this obviously is not a probiotic application.
Finally there have been some recent publications on the use of B. coagulans as a probiotic in shrimp larvae (13, 14) and pigs (15).
In conclusion, there is very little evidence of the use of B. coagulans as a probiotic in humans. There are several studies that show positive effects, but, comparing these studies with those of more well known probiotics, these are very limited. It can thus be stated that there are indications that B. coagulans may act as a probiotic in humans, but many more studies are needed to state that B. coagulans is a probiotic (9).
There are no indications that B. coagulans has any side effects either.
The effectivity of a probiotic preparation obviously is correlated to the purity of the product. It is noteworthy that in several occasions there have been other bacteria isolated from products with spore forming bacteria in high numbers. This has not (yet) been reported for products with lactobacilli or bifidobacteria.
Sanders et al (7) mention 7 products in which other species were present as mentioned on the label, only one of these was labeled L. sporogenes, but contained B. subtilis. In an experiment with only one product in 2000 it was found that the product contained only B. licheniformis (16). In a study by the Dutch Consumer Organisation (17) several other Bacillus species were isolated from products with B. coagulans.
Whether or not this is a coincidence, it may be a warning sign for the producer(s) to be more aware of quality control. So far, there are no indications that these contaminations form a health risk.
R. Hartemink, Wageningen University, Nov. 2007.
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