Getting our gut full - ageing and the potential of probiotics

Old woman answering the door image

By Dinah Woon, Dietitian APD, Yakult Australia

The 2016 Census has just been completed and of all the changes projected for Australia’s population, ageing is considered to be the most dramatic, with the number of individuals aged 65 and over set to increase from 3.2 million in 2012 to up to 5.8 million within the next 15 years1.

What are probiotics?

Probiotics are live microorganisms which when consumed in adequate amounts; confer a health benefit on the host2.

Why probiotics for the elderly?

A healthy digestive system is important throughout life, but never more so than in the later years when the diversity of the gut microbiota changes. The gut microbiota is the name used to describe the multitude of commensal microorganisms found mainly in the colon. This complex microbial system has a strong influence not only on digestive health but on the body as a whole. 

Changes to the gut microbiota, reduce diversity and a decrease in the beneficial endogenous bacteria such as Bifidobacteria, have been linked to increased vulnerability in the elderly to infectious disease. These gut microbiota changes may not necessarily be caused by ageing alone, but can be influenced by the general state of health, malnutrition risk and the need for medications (antibiotics and anti-inflammatory drugs) frequently used in the elderly3. A chronic and systemic state of inflammation known as inflammageing also develops with age, thought to be linked to the changing profile of the gut microbiota 4,5,6.

Research has found a person’s place of residence can affect the gut microbiota profile7. It has been shown to be less diverse for elderly individuals in residential care compared to those living in the community. This loss of diversity correlates with increased frailty7

Collectively, the evidence supports a relationship between diet, the microbiota and health status for the elderly. The beneficial prospect of dietary modulation and simplicity in incorporating probiotic containing foods and or dairy products into their daily diet shows potential.

Gut related conditions/constipation

Gut associated illnesses are known to rise later in life. The estimated mortality rates due to gastrointestinal infections for this age group are 400-fold higher than in younger adults8.

Functional bowel issues such as irritable bowel syndrome (IBS) and constipation are a common occurrence due to:

  • slower transit times due to reduced faecal bacteria mass

  • reduced exercise and increased bed rest in hospitalised older patients3

  • other factors - medication, inadequate water and/or reduction in insoluble fibre intake due to general decline in chewing and swallowing abilities related to ageing

A systematic review on probiotics for constipation by Chmielewska & Szakewska confirmed the efficacy of Bifidobacterium lactis DN-173010, Lactobacillus casei Shirota and E. Coli Nissle 1917 in increasing the frequency of defecation and stool consistency. 

Probiotics in the elderly has shown to shorten bowel transit and soften stools most likely by increasing short-chain fatty acid concentration (butyric, propionic and lactic acid)9. Bacterial production of these organic acids reduces colonic pH, also affecting the re-absorption of water and electrolytes, altering osmotic pressure10, enhancing intestinal motility and subsequently reducing transit times.

Consumption of probiotics has been shown to modulate microbial populations and increase beneficial bacteria numbers. This increase has not been restricted to ingested strains alone, an indication that probiotics are able to increase the numbers of other beneficial bacteria in the gut as well11.   

Common infectious illnesses – immune system

In the elderly immunological changes associated with ageing involve a reduction in immune response efficacy mediated by B and T cells. The immune system becomes less capable of producing antibodies and in mounting a cellular immune response (T-cells). T-cells are vital in activating immune cells that attack viral infected cells or other cells of the adaptive immune response. Natural killer (NK) cells are part of the innate immune system that target infected cells and tumours. A decrease in the numbers and activity of NK cells, phagocytic activity and specific antibody responses have all been reported in older adults12. Common infections such as colds and gastroenteritis spread quickly and may develop into more serious illnesses in residential care occupants. 

One of the key mechanisms of probiotic activity is immune modulation. Human studies using probiotics in the elderly have demonstrated immune modulation benefits in improving the parameters of both the innate and acquired response (see Table 1). Thus probiotics could potentially reverse the age-related weakening of the immune system in the elderly11.   

Probiotics with their general lack of side effects and absence of inference with medications would be considered a logical choice. The benefits of probiotics are strain specific and further adequately powered randomised control trials (RCTs) are warranted to better determine the strains, quantity and duration of probiotic intake required for the elderly. 

When considering a probiotic, choose a quality product with a reputable strain, proven to survive the digestive tract and supported by evidence of benefit in human studies. Claims made on products no matter how general should be truthful with clinical substantiation. 

For more information on probiotics in health and disease, check out Yakult Australia’s scientific and educational probiotic resource, accessible via the resource tab on the Yakult Knowledge website - www.yakultknowledge.com.au.

Table 1: Example of studies on the use of probiotic in the elderly

References

1. Australian Bureau of Statistics, 2013, 3222.0 Population Projections, Australia, 2012 (base) to 2101;  (accessed July 2016)
2. FAQ/WHO, 2002, Working group report on drafting guidelines for the evaluation of probiotics in food, London, Ontario, Canada; (accessed July 2016)
3. Rondanelli M et al. Review on microbiota and effectiveness of probiotic use in elderly. World Journal of Clinical Cases. 2015; 3(2): 156-162.
4. Biagi E et al. Ageing of the human metaorganisms: the microbial counterpart. Age. 2012; 34(1): 247-267.
5. Claesson MJ et al. Composition, variability, and temporal stability of the intestinal microbiota of the elderly. Proc Natl Acad Sci. 2011; 108 (Suppl 1): 4586-91.
6. Duncan SH, Flint HJ. Probiotics and prebiotics and health in ageing populations. Maturitas. 2013; 75(1): 44-50.
7. Claesson MJ et al. Gut microbiota composition correlates with diet and health in the elderly. Nature. 2012; 488 (7410): 178-84.
8. Hébuterne X. Gut changes attributed to ageing: effects on intestinal microflora. Curr Opin Clin Nutr Metab Care. 2003; 6(1): 49-54.
9. Chmielewska A & Szajewska H. Systematic review of randomised controlled trials: probiotic for functional constipation. World J Gastroenterol. 2010; 16(1): 69-75.
10. Koebnick C et al. Probiotic beverage containing Lactobacillus casei Shirota improves gastrointestinal symptoms in patients with chronic constipation. Can J Gastroenterol. 2003; 17(11): 655-659.
11. Martinez GP et al. Understanding gut microbiota in elderly’s health will enable intervention through probiotics. Beneficial Microbes. 2014; 5(3): 235-246.
12. Gill HS et al. Enhancement of immunity in the elderly by dietary supplementation with the probiotic Bifidobacterium lactis HN019. Am J Clin Nutr. 2001; 75(6): 833-9.
13. Moro-Garcia et al. Oral supplementation with Lactobacillus delbrueckii subsp. bulgaricus 8481 enhances systemic immunity in elderly subjects. Age. 2012; 35: 1-16.
14. You J, Yaqoob P. Evidence of immunomodulatory effects of a novel probiotic, Bifidobacterium longum bv. Infantis CCUG 52486. FEMS Immunology and Medical Microbiology. 2012; 66: 353-362.
15. Bosch et al. Lactobacillus plantarum CECT7315 and CECT7316 stimulate immunoglobulin production after influenza vaccination in elderly. Nutricion Hospitalaria. 2012; 27: 504-509.
16. Ahmed et al. Impact of consumption of different levels of Bifidobacterium lactis HN019 on intestinal microflora of elderly human subjects. J Nutr. Health and Aging. 2007; 11: 26-31.
17. Rampelli et al. A probiotics-containing biscuit modulates the intestinal microbiota in the elderly. J Nutr Health Aging. 2013; 17: 166-172.
18. Nagata S et al. Effect of the continuous intake of probiotic-fermented milk containing Lactobacillus casei strain Shirota on fever in a mass outbreak of norovirus gastroenteritis and the faecal microflora in a health service facility for the aged. Br J Nutr. 2011; 106(4): 549-56.
19. Fujita R et al. Decreased duration of acute upper respiratory tract infections with daily intake of fermented milk: a multicentre, double-blinded, randomized comparative study in users of day care facilities for the elderly population. Am J Control. 2013; 41(12):1231-5.
20. Benton et al. Impact of consuming a milk drink containing a probiotic on mood and cognition. European Journal of Clin. Nutr. 2006; 61: 355-361.