As people grow older, their immune system slowly becomes less effective. This natural process makes it harder for the body to fight infections and often reduces how well vaccines work.
Scientists have been searching for safe ways to strengthen immunity in older adults, and a new study suggests that a naturally occurring compound called spermidine may offer some help.
The research was led by scientists from the Max Delbrück Center and the University of Oxford and was published in the journal Aging Cell. The findings suggest that spermidine supplements may improve immune responses in some older adults who do not develop strong protection after vaccination.
Spermidine is a natural substance made by the human body. It is also found in foods such as wheat germ, mushrooms, parmesan cheese, cheddar cheese, soy products, and some whole grains. Previous studies have suggested that spermidine supports a natural cell-cleaning process that becomes less active with age.
One of the biggest challenges of aging is a gradual decline in immune function, known as immunosenescence. As immune cells age, they become less able to respond to infections and vaccines. This is one reason older adults are at greater risk of illnesses such as influenza and COVID-19.
To investigate whether spermidine could improve vaccine protection, the researchers recruited 40 healthy adults aged 65 years and older. After receiving their third COVID-19 vaccine dose, participants took either six milligrams of spermidine or a placebo every day for 13 weeks.
The researchers discovered that about one-quarter of the participants produced only weak antibody responses even after three vaccine doses. These individuals also showed more signs of aging in their immune cells, including increased DNA damage and higher levels of biological markers linked to cellular aging.
Among participants with poor vaccine responses who received spermidine, antibody levels against the virus increased, and their antibodies were better able to neutralize several variants of SARS-CoV-2.
The supplement also reduced markers linked to immune aging and boosted autophagy, a natural recycling process that removes damaged material from cells and helps them function properly.
Another encouraging finding was that the supplement appeared to be safe. The researchers reported no important side effects during the study. However, they emphasized that this was only a small pilot trial designed to explore whether the treatment showed promise.
Because only 40 people took part, the results cannot yet prove that spermidine improves vaccine responses in the wider population. Larger clinical trials will be needed to confirm the findings and determine whether the supplement also improves responses to other vaccines, including seasonal flu vaccines.
Overall, this study provides an interesting new direction for healthy aging research. Instead of creating new vaccines, scientists may be able to improve how older immune systems respond to existing vaccines by targeting the biological processes of aging itself.
If future studies confirm these early results, spermidine could become a simple and affordable way to help protect older adults from infectious diseases.
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