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| A) | Non-profit organization that develops consensus statements and definitions for microbiome-based ingredients | ||
| B) | Publicly traded corporation that evaluates all product claims related to the microbiome | ||
| C) | Government agency that regulates use of microbiome terminology and claims on product labels | ||
| D) | Industry consortium that identifies new microbiome-based product and marketing opportunities |
While there is no regulatory body governing the use of these terms, there are definitions that are generally accepted by the scientific community. The International Scientific Association for Probiotics and Prebiotics (ISAPP) is a nonprofit organization comprised of academic scientists dedicated to promoting research in the field of prebiotics, probiotics, and all associated topics. Over the past decade, this organization has published consensus statements that have helped to define different classes of ingredients and provide guidance for future research [1,2].
| A) | Viable bacteria that are a natural component of the human microbiome | ||
| B) | Live microbes that have demonstrated a health benefit in humans | ||
| C) | Viable, non-pathogenic microbes that do not present a safety risk to humans | ||
| D) | Live micro-organisms that can legally be included in dietary supplement products |
Probiotics: Live microbes that have demonstrated health benefits [1].
Formal definition: Live micro-organisms that, when administered in adequate amounts, confer a health benefit on the host.
| A) | These substances are taken by mouth and only work in the intestine. | ||
| B) | Prebiotics convert to probiotics in the body, where they can impact health. | ||
| C) | Prebiotics encourage the growth of good bacteria and limit the growth of bad bacteria. | ||
| D) | These substances are not well understood and are not likely to be beneficial to health. |
As our knowledge of the human microbiota has expanded, so has the definition of prebiotics. Although prebiotics were originally thought to only be beneficial in the gastrointestinal (GI) tract, we now know that prebiotic effects can occur in any part of the body that hosts microbial species. Over the years, the definition of prebiotic has been rewritten to incorporate this knowledge and to separate prebiotics from other substances that can affect micro-organisms, such as fats, proteins, probiotics, vitamins, and antibiotics [1].
Traditionally, prebiotics have been selected for inclusion in commercially available products due to their utilization by bacteria in the lactobacilli and bifidobacteria genera. In fact, for the most part, prebiotics have been included in commercial products and scientific studies specifically to induce the growth of bifidobacteria (bifidogenesis).
| A) | Fermented food | ||
| B) | Postbiotic | ||
| C) | Prebiotic | ||
| D) | Probiotic |
Inulin is a polysaccharide (long-chain carbohydrate) comprised of up to 60 chains of glucose and fructose molecules. It is isolated from various plant roots and tubers and is commonly used as a food additive to increase bulk and palatability. It is also a natural component of the diet, with the most common food sources being wheat, onions, bananas, leeks, artichokes, and asparagus [4].
Inulin seems to be a preferred food source for lactobacilli and bifidobacteria, leading to its use as a prebiotic. Some research has shown that taking oral inulin increases gut and fecal microbiota diversity and increases concentrations of bifidobacteria. However, not all research to date has confirmed this finding [4].
Inulin is most often derived from chicory (Cichorium intybus). On product labels, it may be referred to as chicory inulin. Another ingredient sometimes found on product labels is chicory fructans. These products typically contain inulin in combination with other fructans such as fructo-oligosaccharides [4].
| A) | Cichorium intybus | ||
| B) | Fructo-oligosaccharides | ||
| C) | Galacto-oligosaccharides | ||
| D) | Xylitol |
In infants who are at risk for allergies, providing an oral syrup or formula containing GOS with either a probiotic or another prebiotic appears to reduce the risk of atopic dermatitis (eczema). However, providing oral GOS and probiotics does not seem to reduce the risk of developing allergic rhinitis or food allergies [6].
| A) | Certain probiotic species and strains seem to be beneficial for the management of chronic GI conditions and the promotion of GI health. | ||
| B) | Most evidence suggests that probiotics do not provide clinically relevant benefits in patients with chronic GI disorders. | ||
| C) | Only combination probiotic products have demonstrated consistent benefit for promoting GI health and reducing chronic symptoms. | ||
| D) | The available research indicates that the majority of commonly used probiotic species can improve symptoms like constipation and diarrhea. |
It is difficult to summarize the evidence for the clinical use of lactobacilli, as each species has demonstrated very different effects in human research. A large body of evidence suggests that certain species and strains may be beneficial for various GI conditions, including abdominal pain, constipation, and diarrhea, as well as for the prevention of atopic disease. However, many species and strains have also failed to show benefit for these uses, so it is important to identify a product containing a species and/or strain that has been evaluated in clinical research [1,16].
As with lactobacilli, it is difficult to summarize the evidence for the clinical use of bifidobacteria. The evidence is variable depending on the species and strain used in clinical research. The currently available evidence suggest that certain species and strains may be beneficial for constipation and IBS, as well as for colic and the prevention of respiratory tract infections. However, other species and strains have either not been evaluated or have failed to show benefit for these uses, so it is important to identify a product containing a species and/or strain that has been evaluated in clinical research [1].
The best evidence for the use of B. coagulans is for constipation and IBS. Research on the use of B. coagulans or B. subtilis for other indications is lacking [8].
| A) | Cells | ||
| B) | Colony-forming units | ||
| C) | Grams | ||
| D) | Milligrams |
Probiotic preparation strength is usually provided as the number of living organisms, or colony-forming units (CFUs), found in each dose. The number of living organisms in a dose can range from 1 million CFUs to 30 billion CFUs, depending on the species and product [9].
| A) | Fermented food | ||
| B) | Postbiotic | ||
| C) | Prebiotic | ||
| D) | Probiotic |
Many of the postbiotics currently being studied are derived from the same live microbial species that are commonly used as probiotics. So far, research has primarily focused on the use of heat-killed versions of the following species [2]:
Bacillus coagulans
Bifidobacterium bifidum
Lactobacillus acidophilus
Lacticaseibacillus paracasei
Lacticaseibacillus rhamnosus
Lactiplantibacillus plantarum
Saccharomyces cerevisiae
| A) | Fermented food | ||
| B) | Microbiota | ||
| C) | Postbiotic | ||
| D) | Synbiotic |
According to the ISAPP definition, synbiotics are a mixture comprising live micro-organisms and substrate(s) selectively utilized by host micro-organisms that confers a health benefit on the host [12]. In simple terms, a synbiotic is a mixture of prebiotic and probiotic.
As the definition suggests, synbiotics are products that combine prebiotics and probiotics together with the goal of providing a synergistic beneficial effect (e.g. to confer a health benefit on the host). Some individual products may be specifically marketed as synbiotics. However, there are also many products marketed as probiotics that have also been formulated to contain prebiotic ingredients.
| A) | Fermented food | ||
| B) | Postbiotic | ||
| C) | Prebiotic | ||
| D) | Probiotic |
Many fermented foods contain high concentrations of alcohol, salt, and/or tyramine. These byproducts may be of concern when used in certain patient populations, such as those with hypertension or those taking certain medications (monoamine oxidase inhibitors [MAOIs], etc.), and should be kept in mind when discussing the use of these products.