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Probiotics: Where Do We Stand?
FROM THE ACADEMY Question of the Month
Probiotics: Where Do We Stand?
T
HE CONCEPT OF PROBIOTICS, A term derived from Greek and meaning “for life,” emerged from observations early in the 19th century by Elie Metchnikoff, known as the “father of probiotics,” who hypothesized that the long and healthy lives of Bulgarian peasants were rooted in their consumption of fermented milks containing beneficial Lactobacillus.1 In 2001, a consensus group of experts convened by the Food and Agriculture Organization (FAO) established a definition for probiotics: “Live microorganisms which when administered in adequate amount confer a health benefit on the host.”2 In addition to probiotics, what are prebiotics and synbiotics and how are they related to probiotics? Prebiotics can be defined as nondigestible food ingredients that stimulate the growth or activity of bacteria. They provide the nutrients for multiplication of a desired probiotic and for other species of microorganisms in the gut that may be favorable to health. Much of the research on prebiotics has centered on oligosaccharides. General fructooligosaccharides (FOS), also called fructans and inulin-type fructans, are the most common oligosaccharides in use in the United States.3 Synbiotics is a term that is used for products that contain both probiotic microorganisms and a prebiotic (usually an oligosaccharide) that will provide nutrients to promote growth and establishment of the probiotic bacteria.3 Probiotics are available as dietary supplements and foods, with global sales of products expected to reach $42 billion in 2016.4 Probiotics sold as dietary supplements or foods must
This article was written by Wendy Marcason, RD, of the Academy of Nutrition and Dietetics’ Knowledge Center Team, Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected]. http://dx.doi.org/10.1016/j.jand.2013.08.010
1424
comply with applicable Food and Drug Administration labeling regulations. Probiotics are promoted to improve digestion, strengthen immunity, help in weight loss, and even protect against gum disease and colon cancer, in addition to improving general health. The most common probiotics found in dietary supplements and foods include Lactobacillus species, Bifidobacterium species, and the yeast Saccharomyces boulardii.5 Evidence-based reviews indicate that certain strains of probiotics contribute to the microbial balance of the gastrointestinal tract, supporting the immune system and reducing inflammation in the gut. It is important to remember that there is no generic equivalence between probiotic strains or products. One probiotic product should not be considered the same as another, even if they contain the same species.5 Evidence largely supports the use of probiotics for antibiotic-associated diarrhea and clostridium difficile. The evidence looks promising for the use in rotaviral diarrhea, irritable bowel syndrome, necrotizing enterocolitis in preterm infants, and for preventing respiratory infections. The evidence for the use of probiotics for vaginal candidiasis and ventilator-associated pneumonia is primarily negative.5 Probiotics have a very good safety profile. Some minor side effects that have been reported are thirst, constipation, bloating, flatulence, nausea, vomiting, abdominal pain, rash, and diarrhea.6 Although serious complications are extremely rare, reported side effects have included endocarditis, liver abscess, sepsis, and fungemia. Most cases of invasive infections associated with probiotic use have occurred in patients with intravenous catheters, elderly people, and immunocompromised populations.6 Concerns have also been raised about the quality of probiotic products. Some products have been found to contain smaller numbers of live microorganisms than expected. In addition, some products have been found to contain bacterial strains other than those listed
JOURNAL OF THE ACADEMY OF NUTRITION AND DIETETICS
as ingredients.7 With regard to drug and nutrient interaction, be aware that calcium in dairy foods can interfere with the absorption of certain antibiotics.4 Our understanding of probiotics is a work in progress. The challenge to develop evidence-based practice guidelines for probiotics, prebiotics, and synbiotics is the need for additional research in the form of well-designed, controlled trials for the numerous proposed functions of these products.
References 1.
Douglas LC, Sanders ME. Probiotics and prebiotics in dietetic practice. J Am Diet Assoc. 2008;108(3):510-521.
2.
Food and Agriculture Organization of the United Nations and World Health Organization. Health and nutritional properties of probiotics in food, including powder milk with live lactic acid bacteria. http://www. who.int/foodsafety/publications/fs_manage ment/en/probiotics.pdf. Accessed July 26, 2013.
3.
Joneja JV. The Health Professional’ Guide to Food Allergies and Intolerance. Chicago, IL: Academy of Nutrition and Dietetics; 2013.
4.
Probiotics: Pros and cons. Berkeley Wellness Letter. March 2013. http://www. berkeleywellness.com/supplements/othersupplements/article/probiotics-pros-andcons. Accessed July 26, 2013.
5.
Natural Medicines Comprehensive Database. Probiotics. http://naturaldatabase. therapeuticresearch.com/ce/ceCourse.aspx? s=ND&cs=&pm=5&pc=13-103. Accessed July 26, 2013.
6.
Upadhyay N, Moudgal V. Probiotics: A review. J Clin Outcomes Manage. 2012;19(2): 76-84.
7.
National Center for Complementary and Alternative Medicine. Oral Probiotics: An Introduction. http://nccam.nih.gov/health/ probiotics/introduction.htm Accessed July 26, 2013.
Additional Resources Position of the Academy of Nutrition and Dietetics: Functional Foods. http://www.eatright. org/About/Content.aspx?id¼6442460576 Foroutan R. The history and health benefits of fermented foods. Food & Nutrition Magazine website. Available free to Academy members at http://www.foodandnutrition.org/Winter-2012/ The-History-and-Health-Benefits-of-FermentedFood/ Sanders ME, Guarner F, Guerrant R, et al. An update on the use and investigation of probiotics in health and disease. Gut. 2013;62(5): 787-796. http://gut.bmj.com/content/62/5/787. long.
ª 2013 by the Academy of Nutrition and Dietetics.
Probiotics: Where Do We Stand?
T
HE CONCEPT OF PROBIOTICS, A term derived from Greek and meaning “for life,” emerged from observations early in the 19th century by Elie Metchnikoff, known as the “father of probiotics,” who hypothesized that the long and healthy lives of Bulgarian peasants were rooted in their consumption of fermented milks containing beneficial Lactobacillus.1 In 2001, a consensus group of experts convened by the Food and Agriculture Organization (FAO) established a definition for probiotics: “Live microorganisms which when administered in adequate amount confer a health benefit on the host.”2 In addition to probiotics, what are prebiotics and synbiotics and how are they related to probiotics? Prebiotics can be defined as nondigestible food ingredients that stimulate the growth or activity of bacteria. They provide the nutrients for multiplication of a desired probiotic and for other species of microorganisms in the gut that may be favorable to health. Much of the research on prebiotics has centered on oligosaccharides. General fructooligosaccharides (FOS), also called fructans and inulin-type fructans, are the most common oligosaccharides in use in the United States.3 Synbiotics is a term that is used for products that contain both probiotic microorganisms and a prebiotic (usually an oligosaccharide) that will provide nutrients to promote growth and establishment of the probiotic bacteria.3 Probiotics are available as dietary supplements and foods, with global sales of products expected to reach $42 billion in 2016.4 Probiotics sold as dietary supplements or foods must
This article was written by Wendy Marcason, RD, of the Academy of Nutrition and Dietetics’ Knowledge Center Team, Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected]. http://dx.doi.org/10.1016/j.jand.2013.08.010
1424
comply with applicable Food and Drug Administration labeling regulations. Probiotics are promoted to improve digestion, strengthen immunity, help in weight loss, and even protect against gum disease and colon cancer, in addition to improving general health. The most common probiotics found in dietary supplements and foods include Lactobacillus species, Bifidobacterium species, and the yeast Saccharomyces boulardii.5 Evidence-based reviews indicate that certain strains of probiotics contribute to the microbial balance of the gastrointestinal tract, supporting the immune system and reducing inflammation in the gut. It is important to remember that there is no generic equivalence between probiotic strains or products. One probiotic product should not be considered the same as another, even if they contain the same species.5 Evidence largely supports the use of probiotics for antibiotic-associated diarrhea and clostridium difficile. The evidence looks promising for the use in rotaviral diarrhea, irritable bowel syndrome, necrotizing enterocolitis in preterm infants, and for preventing respiratory infections. The evidence for the use of probiotics for vaginal candidiasis and ventilator-associated pneumonia is primarily negative.5 Probiotics have a very good safety profile. Some minor side effects that have been reported are thirst, constipation, bloating, flatulence, nausea, vomiting, abdominal pain, rash, and diarrhea.6 Although serious complications are extremely rare, reported side effects have included endocarditis, liver abscess, sepsis, and fungemia. Most cases of invasive infections associated with probiotic use have occurred in patients with intravenous catheters, elderly people, and immunocompromised populations.6 Concerns have also been raised about the quality of probiotic products. Some products have been found to contain smaller numbers of live microorganisms than expected. In addition, some products have been found to contain bacterial strains other than those listed
JOURNAL OF THE ACADEMY OF NUTRITION AND DIETETICS
as ingredients.7 With regard to drug and nutrient interaction, be aware that calcium in dairy foods can interfere with the absorption of certain antibiotics.4 Our understanding of probiotics is a work in progress. The challenge to develop evidence-based practice guidelines for probiotics, prebiotics, and synbiotics is the need for additional research in the form of well-designed, controlled trials for the numerous proposed functions of these products.
References 1.
Douglas LC, Sanders ME. Probiotics and prebiotics in dietetic practice. J Am Diet Assoc. 2008;108(3):510-521.
2.
Food and Agriculture Organization of the United Nations and World Health Organization. Health and nutritional properties of probiotics in food, including powder milk with live lactic acid bacteria. http://www. who.int/foodsafety/publications/fs_manage ment/en/probiotics.pdf. Accessed July 26, 2013.
3.
Joneja JV. The Health Professional’ Guide to Food Allergies and Intolerance. Chicago, IL: Academy of Nutrition and Dietetics; 2013.
4.
Probiotics: Pros and cons. Berkeley Wellness Letter. March 2013. http://www. berkeleywellness.com/supplements/othersupplements/article/probiotics-pros-andcons. Accessed July 26, 2013.
5.
Natural Medicines Comprehensive Database. Probiotics. http://naturaldatabase. therapeuticresearch.com/ce/ceCourse.aspx? s=ND&cs=&pm=5&pc=13-103. Accessed July 26, 2013.
6.
Upadhyay N, Moudgal V. Probiotics: A review. J Clin Outcomes Manage. 2012;19(2): 76-84.
7.
National Center for Complementary and Alternative Medicine. Oral Probiotics: An Introduction. http://nccam.nih.gov/health/ probiotics/introduction.htm Accessed July 26, 2013.
Additional Resources Position of the Academy of Nutrition and Dietetics: Functional Foods. http://www.eatright. org/About/Content.aspx?id¼6442460576 Foroutan R. The history and health benefits of fermented foods. Food & Nutrition Magazine website. Available free to Academy members at http://www.foodandnutrition.org/Winter-2012/ The-History-and-Health-Benefits-of-FermentedFood/ Sanders ME, Guarner F, Guerrant R, et al. An update on the use and investigation of probiotics in health and disease. Gut. 2013;62(5): 787-796. http://gut.bmj.com/content/62/5/787. long.
ª 2013 by the Academy of Nutrition and Dietetics.