As the body ages, the immune system changes and goes through a remodeling process. There is a reduction in immune cell functions which can lead to an increasing risk of infection, viral reactivation, and increased risk of autoimmune disease and cancer.

According to a review published last week in the European Journal of Clinical Nutrition, researchers investigated the effects of probiotic supplementation on natural killer cell function in healthy elderly individuals.

This review included six randomized control trials consisting of 364 healthy individuals over 65 years of age. Five of the studies used Lactobacillus alone or in combination with Bifidobacterum and one study used only Bacillus coagulans. The dosing ranged between 1 billion and 4 billion colony-forming units over a duration of 3 to 12 weeks. As a result, probiotic supplementation significantly increased natural killer (NK) activity in healthy elderly individuals. Natural killer cells are an essential part of the innate immune system and regulating the immune response. NK cells are involved in eliminating viruses and play a role in cancers and autoimmune disorders. This is the first review to only address randomized control trials and markers of NK cell function.

Accumulating research also demonstrates the association of the gut microbiome to health status and aging. There is evidence that age-related changes in the gut microbiome may be related to elevated inflammatory makers and numerous geriatric conditions such as sarcopenia, frailty, and cognitive decline. Probiotics have the potential to rebalance gut microbiota and modulate gut immune response inhibiting the NF-κB pathway as well as control microbial populations, alter cytokine expression, increase secretory IgA, increase natural killer cell activity, and reduce the risk of infections.

Previous research has demonstrated how the gastrointestinal tract changes with aging and how this impacts overall health. As one ages, the gut has an increase in interleukin 6 (IL-6) which causes the immune system to release IL-6 and trigger inflammation.

Increased levels of IL-6 directly lead to increased intestinal permeability with no physical differences seen in its structure. Researchers also demonstrated that there was an association with a decreased immune response to microbes with aging, which may contribute to an increased susceptibility to infection.

These results demonstrate that probiotics can significantly increase immune function and reduce inflammation in middle-age and older adults. Other nutrients to consider for aging, inflammation, and the immune system include tocotrienols, geranylgeraniol, resveratrol, quercetin, and specialized pro-resolving mediators.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS Source: Gui Q, Wang A, et al. Effects of probiotic supplementation on natural killer cell function in healthy elderly individuals: a meta-analysis of randomized controlled trials. Eur J Clin Nutr. 2020 Jun 8: 1-8.

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