Common infections among older people include for example bronchitis, chronic clostridium difficile infection and pneumonia. Older age also increases the risk of diseases such as cardiovascular (CVD), pulmonary, and neurodegenerative conditions (eg Parkinson’s, and Alzheimer) and cancer (eg myeloproliferative neoplasms, breast, and prostate cancer).^2,3

The risks of these infection and diseases in older patients are increased by environmental conditions (eg stressors), but also and likely most importantly, the capacity of the body to respond and adapt to these stressors. Genetics also play a role.³

What happens to our bodies as we grow older?

As we grow older, our bodies undergo complex changes, leading to dysfunction of the immune system. This dysfunction causes increases in the concentration of inflammatory markers in the blood, a phenomenon known as ‘inflammaging’. The good news is that the effects of ‘inflammaging’ can be reduced by adequately addressing specific factors.²

Can we turn back the clock of time?

According to Franceschi et al, there are two ways – although the second may only be possible in the distant future – in which we can mitigate some of the consequences of ‘inflammaging’:³

• Through changes in lifestyle, and possibly drugs or medical treatments. This strategy should help people to stay healthy and active as long as possible and postpone age-related diseases for decades, ideally until the apparently inevitable limit of their lifespan.
• Rejuvenating or regenerating human tissues, organs, and the whole body.

Hutchinson et al, however, proposes a third option. According to the team, numerous studies have shown that gut microbiota play an extremely important role in the onset of age-related diseases and ‘manipulating’ these microorganisms can mitigate some of effects of ‘inflammaging’.²

A vast array of microorganisms colonise the gut and the majority of these microorganisms are bacteria (but also viruses, fungi, and protozoa) that have many beneficial interactions with each other and their host. Microbiota are known to impact numerous processes within the gut including the mucosal immune system, digestion, and vitamin synthesis.²

But the effect of the gut microbiota extends far beyond the gut, as it is implicated in immune-related disorders such as irritable bowel syndrome, diabetes, and low-grade inflammation. Studies have demonstrated that the gut microbiome in older people differs from that of younger people.²

In addition to demonstrating that ageing is associated with alterations in the microbiome, a growing number of studies suggest that correlations exist between microbiota composition and ageing-associated clinical conditions and diseases.²

Distinct microbiota profiles have been correlated with for example C. difficile colitis, colon cancer, cardiovascular disease, frailty, and systemic inflammation in the elderly.²

Furthermore, a growing number of studies suggest that the gut–brain axis, a bidirectional route of communication between the gastrointestinal tract and the central nervous system plays a significant role in host physiology and disease, as alterations in gut microbiota composition have been associated with depression, brain development, cognition, and neurodegenerative diseases.²

Recently, a role for the gut microbiota has been implicated in neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease. these findings suggest that manipulation of the microbiota composition in the elderly is a promising potential strategy to prevent or reduce age-associated disease and disability.²

What are the effects of probiotic supplementation in older people?

Hutchinson et al reviewed 17 randomised placebo-controlled trials studying different outcomes of probiotic treatment in older adults. They found that probiotic supplementation:

• Positively affects immnunosenescence by counteracting reduced naïve T-cell production and memory T-cell accumulation commonly associated with ageing and increasing the numbers of regulatory T- and B-cells.
• Decreases CD8 + CD28null cell numbers, which is significant as the accumulation of these cells has been linked to reduced immune response to infection and immunisation response in the elderly.
• May be efficacious in increasing immune cell-naivety and shifting cytokine production to a more anti-inflammatory profile. Increased naivety and reduced memory/effector cell populations would be extremely beneficial in the elderly, as it would improve response to infections.
• Has a positive impact on the incidence of common cold and decreased episode duration of common infectious diseases. These immunological benefits may also be helpful in improving vaccine response.
• Positively impacts general well-being, decreases anxiety and depression scores, and decreases anxiety in participants suffering from indigestion and abdominal pain.
• Has beneficial effects on serum lipid profiles that may lead to reductions in the risk of CVD.
• Improves serum calcium levels. Bone loss is a common problem among older people - especially among women (see article on page 18). Supplements of calcium are therefore recommended for osteoporotic patients with low calcium intake/absorption. Additionally, gut microbiota is increasingly recognised as an important determinant of bone health and compelling evidence supporting that probiotics may improve bone health is starting to accumulate. In elderly postmenopausal women, probiotics even seem to reduce bone loss in a quite similar magnitude as observed with calcium + vitamin D supplements.

REFERENCES:

1. Kechagia M, et al. Health benefits of probiotics: a review. ISRN Nutr, 2013.
2. Hutchinson AN, et al. The Effect of Probiotics on Health Outcomes in the Elderly: A Systematic Review of Randomized, Placebo-Controlled Studies. Microorganisms, 2021. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
3. Franceschi C, et al. The Continuum of Aging and Age-Related Diseases: Common Mechanisms but Different Rates. Front Med (Lausanne), 2018.