Protecting Against Age-Related Immunosenescence

Healthy Aging

A New Study on How C15:0 Can Both Calm Inflammaging & Boost Good Immunity

It’s International Longevity Month, which coincides well with a new study from Kumar et al. that evaluated age-related changes in our metabolome that affect our immune responses. To cut to the chase, this peer-reviewed study published in Science Advances showed C15:0 as the strongest fatty acid predictor of healthy immune function among older people. High five, C15:0.

So, how does our immune system change as we age?

Simply put, our immunity becomes unbalanced as we age.

• On one hand, we experience increased and unwanted production of pro-inflammatory cytokines (like IL-6) that lead to systemic inflammaging. As reviewed by Choperchini et al. and Tylutka et al., this chronic, low-lying inflammation affects our muscles, vessels, heart, liver, joints, brain and, well, just about everything.
• On the other hand, aging also results in decreased lymphocytes, especially lymphocytes that help us produce antibodies. As described by Fulop et al., this is important because antibodies help protect us against specific infections, such as influenza (aka flu). Termed immunosenescence, this immune-suppressing effect in older people results in a less robust immune boost response from flu shots compared to younger people.

One big goal to help support our longevity? Keep our overactive pro-inflammatory cytokines at bay, while still allowing our immune system to defend itself effectively against viruses and other pathogens.

Links between inflammaging and immunosenescence.

While this goal may appear like a conflict of immune-interest, there is actually sound science on how taming inflammaging can also boost a proper immune response. Here’s one example from Teissier et al.:

• As we age, many pro-inflammatory cytokines go up, including interleukin 15 (aka IL-15).
• IL-15 not only contributes to inflammaging, but it also blocks important production of antibodies against influenza.
• Thus, lowering IL-15 may help our bodies produce antibodies that protect us against the flu.

With that background, we can get to the Kumar et al. study.

Higher C15:0 predicts lower IL-15… with improved flu antibody production.

Kumar et al.’s study included 235 people who were older than 65 years old. This group received flu shots and were evaluated for how well they developed antibodies against influenza. “Poor responders” were those who did not mount a good immune response.

They then used untargeted metabolomics to evaluate hundreds of molecules in the blood to better understand differences between the poor and good responders.

What did they find?

• People with baseline higher IL-15 levels had lower antibody production post-shot (aka, they were poor responders).
• IL-15 activated natural killer cells that suppressed the production of antibodies.
• People with higher C15:0 levels had lower IL-15 levels. The researchers propose that C15:0’s immune calming effect led to healthier antibody production against influenza.
• Among all fatty acids assessed, C15:0 had the most statistically significant association with this benefit.

Based on their study’s findings, Kumar et al. suggest that lower C15:0, which naturally occurs as we age, leads to increased IL-15, resulting in poorer immune response to flu shots. Further, the authors propose that increasing C15:0 before vaccination may effectively lower IL-15 and improve flu shot responses, especially among older people.

It is important to note that this study was one of association (not causation), and more studies are needed to test this hypothesis. This study is encouraging, however, on yet another benefit of C15:0 that may support our health with longevity.