Gut Microbiota Diversity in the Young and Old
Share this post
A factor in disease conditions and aging?
In recent decades, there has been an explosion of information regarding the role that the human microbiota plays in both health and disease. Projects such as the National Institutes of Health Human Microbiome Project, and similar collaborative efforts in other countries, have focused on the collection of human microbiome data from large populations for the purpose of increasing our knowledge about the microbes inhabiting the body., Combined with population data, these projects offer information about the impact of host and environmental factors on microbiota in average, healthy populations, as well as microbiome-associated variables that may point to disease risks.
Our microbiome includes the microbes that find their home not only in the gastrointestinal (GI) tract, but also the on the skin, respiratory tract, urogenital tract, and even the brain. These microbes predominantly consist of bacteria, although nonbacterial organisms such as viruses and fungi are also represented. The term “microbiome” refers not only to the microbiota and their habitat but also the collective genomes of the microbes, known as the “metagenome.” Although some references estimate that the 100 trillion organisms comprising the human microbiome represent 10 times the number of cells in the human body, a recent paper suggests that the ratio of microbes to human cells is closer to 1.3:1. Regardless, both of these estimates reflect a substantial microbial population, whose function impacts not only the interfacing epithelial tissues, but also the function of our body within.
By far, the largest population of these microbes is found in the GI tract, which is home to nearly 1013 to 1014 microorganisms that represent between 500 to 1,000 unique bacterial species., The most significant influences on the development of the infant gut have been well established to be mode of birth and early feeding. Compared to infants born vaginally, infants born by cesarean section have decreased bacterial diversity, or “richness” in the gut., Infants who are formula-fed also have decreased bacterial richness in the gut compared to those who are breastfed. The neonatal gut continues to populate and diversify through childhood until it reaches a high level of diversity similar to the adult gut by about two to three years of age. Studies have found an increased risk of obesity in children born by cesarean section, while in adulthood, a lack of microbial diversity has been shown to be associated with an increased risk of obesity, metabolic syndrome, high cholesterol levels and inflammation.
Gut microbial diversity in the elderly
A reduction in in gut microbiota diversity is not only seen with obesity, but also in the process of aging, particularly with early frailty and the use of multiple medications., Reduced diversity can contribute to the increased representation of pathogens, as well as a decline in the healthy immune system response to infections. Probiotics have been shown to be effective for restoring the microbiota decline seen with aging, and in clinical studies with elderly populations they have been observed to improve digestive symptoms and immune system function., Probiotics also have evidence indicating they may prevent C. difficile infection which the elderly, particularly those in hospitals and residential facilities, are more at risk of. Bifidobacterium lactis is one specific strain being shown in the elderly to increase immune surveillance, which is not only important for infections, but also the prevention of cancer.
Gut microbial diversity in children
In children, a healthy and diverse gut microbiome is important for reducing infection and may help reduce the occurrence of common pediatric conditions. Reduced gut microbiota diversity in children has been shown to be associated with allergic disease, asthma and inflammatory bowel disease (IBD) in children.,, Good results with the probiotic combination of Lactobacillus acidophilus DDS® -1 and B. lactis UABLA-12™ have been seen in clinical trials in settings of atopic dermatitis and respiratory tract health. In children ranging from one to three years in age, the combination was shown to significantly improve eczema symptoms and reduce the need for topical hydrocortisone cream. It also reduced the time to recovery from acute respiratory tract infections as well as symptom severity and the need for medications.,
The gut microbiota will clearly be a focus of research for microbiologists and physicians for years to come, however, studies such as these increasingly shed light on the importance of the healthy bacteria in the gut. Select strains of probiotic bacteria such as B. lactis and L. acidophilus have been demonstrated to deliver therapeutic benefit and are important to consider when supporting the health of the young and the elderly.
Click here to see References
 Turnbaugh PJ, et al. The human microbiome project. Nature. 2007 Oct 18;449(7164):804-10.
 Qin J, et al. A human gut microbial gene catalogue established by metagenomic sequencing. Nature. 2010 Mar 4;464(7285):59-65.
 Falony G, et al. Population-level analysis of gut microbiome variation. Science. 2016 Apr 29;352(6285):560-4.
 Ursell LK, et al. Defining the human microbiome. Nutr Rev. 2012 Aug;70 Suppl 1:S38-44.
 Cong X, et al. Early life experience and gut microbiome: The brain-gut-microbiota signaling system. Adv Neonatal Care. 2015 Oct;15(5):314-23.
 Sender R, et al. Are we really vastly outnumbered? Revisiting the ratio of bacterial to host cells in humans. Cell. 2016 Jan 28;164(3):337-40.
 Bäckhed F, et al. Host-bacterial mutualism in the human intestine. Science. 2005 Mar 25;307(5717):1915-20.
 Zhu B, et al. Human gut microbiome: the second genome of human body. Protein Cell. 2010 Aug;1(8):718-25.
 Martin R, et al. Early-life events, including mode of delivery and type of feeding, siblings and gender, shape the developing gut microbiota. PLoS One. 2016 Jun 30;11(6):e0158498.
 Dominguez-Bello MG, et al. Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns. Proc Natl Acad Sci U S A. 2010 Jun 29;107(26):11971-5.
 Madan JC, et al. Association of cesarean delivery and formula supplementation with the intestinal microbiome of 6-week-old infants. JAMA Pediatr. 2016 Mar;170(3):212-9.
 Azad MB, et al. Gut microbiota of healthy Canadian infants: profiles by mode of delivery and infant diet at 4 months. CMAJ. 2013 Mar 19;185(5):385-94.
 Koenig JE, et al. Succession of microbial consortia in the developing infant gut microbiome. Proc Natl Acad Sci U S A. 2011 Mar 15;108 Suppl 1:4578-85.
 Yuan C, et al. Association between cesarean birth and risk of obesity in offspring in childhood, adolescence, and early adulthood. JAMA Pediatr. 2016 Nov 7;170(11):e162385.
 Le Chatelier E, et al. Richness of human gut microbiome correlates with metabolic markers. Nature. 2013 Aug 29;500(7464):541-6.
 Turnbaugh PJ, et al. A core gut microbiome in obese and lean twins. Nature. 2009 Jan 22;457(7228):480-4.
 Calvani R, et al. Of Microbes and Minds: A Narrative Review on the Second Brain Aging. Front Med (Lausanne). 2018 Mar 2;5:53.
 Jackson MA, et al. Signatures of early frailty in the gut microbiota. Genome Med. 2016 Jan 29;8(1):8.
 Ticinesi A, et al. Gut microbiota composition is associated with polypharmacy in elderly hospitalized patients. Sci Rep. 2017 Sep 11;7(1):11102.
 Mello AM, et al. Gastrointestinal Microbiota and Their Contribution to Healthy Aging. Dig Dis. 2016;34(3):194-201.
 Ouwehand AC, et al. Influence of a combination of Lactobacillus acidophilus NCFM and lactitol on healthy elderly: intestinal and immune parameters. Br J Nutr. 2009 Feb;101(3):367-75.
 Gill HS, et al. Enhancement of immunity in the elderly by dietary supplementation with the probiotic Bifidobacterium lactis HN019. Am J Clin Nutr. 2001 Dec;74(6):833-9.
 Goldenberg JZ, et al. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database Syst Rev. 2017 Dec 19;12:CD006095.
 Miller LE, et al. The Effect of Bifidobacterium animalis ssp. lactis HN019 on Cellular Immune Function in Healthy Elderly Subjects: Systematic Review and Meta-Analysis. Nutrients. 2017 Feb 24;9(3). pii: E191.
 West CE, et al. Gut microbiota and allergic disease: new findings. Curr Opin Clin Nutr Metab Care. 2014 May;17(3):261-6.
 Abrahamsson TR, et al. Low gut microbiota diversity in early infancy precedes asthma at school age. Clin Exp Allergy. 2014 Jun;44(6):842-50.
 Docktor MJ, et al. Alterations in diversity of the oral microbiome in pediatric inflammatory bowel disease. Inflamm Bowel Dis. 2012 May;18(5):935-42.
 Gerasimov SV, et al. Probiotic supplement reduces atopic dermatitis in preschool children: a randomized, double-blind, placebo-controlled, clinical trial. Am J Clin Dermatol. 2010;11(5):351-61.
 Gerasimov S, Cycura O. Role of probiotics in attenuation of acute respiratory tract infections in preschool and primary school children. Eur Resp J 2012:351-361.
 Gerasimov SV, et al. Role of short-term use of L. acidophilus DDS-1 and B. lactis UABLA-12 in acute respiratory infections in children: a randomized controlled trial. Eur J Clin Nutr. 2016 Apr;70(4):463-9.
Share this post
Dr. Carrie Decker
Vitamin C to Ease the Pain
Nutritional support for acute, chronic, surgical, and cancer-related pain Part 1 in our three-part series on vitamin C, pain, and opioid addiction. What do humans have in common with other primates, bats, and guinea pigs? (No, not a love of cheese!) We cannot make L-gulonolactone oxidase (GLO), the enzyme needed to biosynthesize ascorbate (vitamin…
Hemicellulose – A Natural Immune Enhancer?
Plant and Mushroom Blend Provides Gut and Immune Support Hemicellulose isn’t a new thing. In fact, it is as timeless as the plants and fungi that cover the face of our planet. Within plants, much like cellulose, hemicellulose is structural in function. It differs from cellulose in that it is a polysaccharide comprised of…
Intermittent Fasting, Part 1 of 2
Different intermittent fasting strategies, and how eating outside of “normal” eating hours can adversely affect health In this two-part series, Dr. Michael Brown, ND, takes a comprehensive look at this popular and trending approach to a healthier lifestyle. In Part I, a look at the different approaches to intermittent fasting and how nighttime eating…
Healthy Mouth, Healthy Body
Why we shouldn’t ignore the oral microbiome If you’re like me, you’d prefer not to dwell on the millions of bacteria living in your mouth. But if you care about your health, you can’t ignore the oral microbiome! Up to 700 different species of bacteria live in various niches within the mouth.,, Even individuals…
The Clinical Role of Gastrointestinal Binders
Useful agents for detoxification and Herxheimer reactions? In today’s world of industry, technology, and rapid growth, man is globally exposed to more toxic chemicals, including heavy metals, than ever before., Toxic heavy metals, herbicides, pesticides, plasticizers, and other potentially toxic compounds that we are exposed to that do not naturally occur in the body…
Intermittent Fasting, Part 2 of 2
The clinical data on intermittent fasting, and comparisons with caloric-restriction diets In this two-part series, Dr. Michael Brown, ND, takes a comprehensive look at this popular and trending approach to a healthier lifestyle. In Part I, a look at the different approaches to intermittent fasting and how nighttime eating can adversely affect health. In…