How can I boost my immune system?

Dear Alice,

I was wondering what I personally can do (habits, diets, activities) to strengthen my immune system? Thank you!


Dear GAEF,

This is a great question, with a slightly complex answer. Researchers and public health professionals have yet to find direct and conclusive scientific evidence linking certain lifestyle habits to strengthen the immune system. However, researchers do have a pretty good idea about how to protect your body, and thereby your immune system, from environmental harm (more on that later). With that in mind, adopting and maintaining healthy behaviors and routines — such as eating nutritious foods, getting enough sleep, and staying active — are your best bet for keeping your immune system functioning optimally.

There are a few reasons for the lack of scientific evidence regarding boosting immune function. First, the immune system, which helps protect the body from microorganisms that cause infection and disease, is very complex. Researchers are still trying to understand this complicated and intricate system, which makes it difficult to determine what factors actually improve it. For example, the immune system consists of a variety of different cells that help protect a person’s body from different infections and diseases. Although increasing the number of cells in your body may enhance immune functioning, scientists aren't sure which kind or number of cells in the immune system to increase. In addition, an increase of cells may lead to negative side effects; for example, athletes who participate in practices to increase their blood cells may increase their risk of stroke with these practices.

Despite the lack of evidence on factors that directly enhance immune functioning, there are a number of actions you can take to keep your body healthy and strong, and in turn prevent illness:

  • Wash your hands: Be diligent about washing your hands thoroughly and often with soap and warm water, particularly before eating and after using the bathroom.
  • Get at least seven to nine hours of quality sleep every night: Deep sleep stimulates the immune system, so it's ideal to try to get enough quality sleep. For more information on how to maximize your slumber, check out the Sleep category in the Go Ask Alice! archives.
  • Fit in some physical activity: Regular physical activity has been shown to improve cardiovascular health, decrease blood pressure, and help defend the body from disease and infection. It also helps with blood circulation, which makes it easier for the cells in the immune system to function efficiently.
  • Chow down on fruits and vegetables: Taking a daily multi-vitamin and other supplements may have their benefits, but experts recommend getting as many vitamins and minerals as possible through food. For more information on maintaining a nutritious diet, check out the Optimal Nutrition category in the Go Ask Alice! Nutrition & Physical Activity archives.
  • Reduce and manage stress: There’s evidence of the relationship between the mind and body, but researchers are currently examining the link between long periods of stress and a weakened immune response.
  • Consume alcohol moderately (if at all): Drinking alcohol in large amounts has been linked to a weakened immune response.
  • Quit smoking or don't start: Smoking weakens the immune system and can lead to lung and other cancers.
  • Get preventative vaccines: There are vaccines available for a number of viruses so you could talk with your health care provider about what may be best for you.

While there are factors that may influence immunity that are unchangeable such as genes, age, and family histories, people who incorporate these habits into their daily living may see improvements in their overall health and immune response. If you'd like to learn more about how to incorporate healthy practices into your day-to-day, you might consider making an appointment with your health care provider.

Last updated Mar 27, 2020
Originally published Apr 01, 2005

Submit a new comment


This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

The answer you entered for the CAPTCHA was not correct.