As the body ages, so does the immune system. The immune system usually becomes less effective in older age, a process known as immunosenescence. This can increase the risk of:

  • infections
  • severe responses to infections
  • cancer
  • autoimmune disease
  • cardiovascular disease
  • neurodegenerative disease

Experts are still studying the exact reasons for this. But some of the contributing factors seem to include:

  • A decline in the number and function of immune cells: In older age, the immune system may not produce as many immune cells, like T-cells and macrophages, and the ones it does produce may be less effective. A less effective immune response can make it more difficult for the body to overcome infection or target mutated cells that can lead to cancer.
  • Increased inflammation: Older age and ineffective immune system functioning are associated with chronic low-grade inflammation. This may result from an imbalance in the anti-inflammatory and pro-inflammatory immune cells. This inflammation can affect the immune system’s response to threats and increase tissue damage.
  • Reduced response to vaccines: Because the immune system is less robust in older age, it typically develops a less effective response to many vaccines. This makes it easier for viruses to spread.

While you can’t prevent aging, researchers have determined a few factors that may reduce your risk of impaired immune system functioning as you age. These include:

  • Maintaining a healthy gut microbiome: Research suggests that following a Mediterranean diet is associated with a more diverse gut microbiome. The Mediterranean diet incorporates many plant-based food sources that provide fiber, which helps feed your healthy gut bacteria. It also limits processed foods, red meat, and refined grains. Taking probiotics may also help.
  • Getting regular physical activity: Regular physical activity can improve immune responses in older adults. You can follow an exercise routine designed for older adults that includes low impact activities like walking.
  • Getting recommended vaccines: Some vaccine formulations are modified for older adults to include a high dose or more frequent dosing. Staying current on vaccines can help prevent severe illness, which can negatively impact immune function.
  • Reducing oxidative stress: As the immune system ages, it’s less able to manage oxidative stress, an imbalance of antioxidants and free radicals (which cause cellular damage).

Researchers are investigating the effects of medications on aging. Some research suggests that metformin, a common medication for type 2 diabetes, may reduce oxidative stress and preserve immune cell health in older adults. However, more research is still needed. This medication is not currently approved for immune health.

Some research suggests that taking probiotics may help support gut microbiome diversity, which can help support the immune system.

The same researchers note that vitamin E supplements may also support immune cell production in older adults. You can also get vitamin E from eating nuts and seeds, which also contain beneficial fiber and other nutrients.