The immune system protects the body from pathogens. It’s made up of the innate immune system (the skin, mucus membranes, and inflammatory response) and the adaptive immune system (specific cellular responses for each pathogen).

Habits that can help the functioning of the immune system include:

  • Eating enough nutrients. This is key to a healthy immune system. Proteins are especially important for a working immune system because they create and maintain the skin and mucosal barriers to protect against infections. They also help mount an immune defense response. Having adequate micronutrients (vitamins and minerals), fiber, and unsaturated fatty acids also helps with immunity.
  • Being up to date on vaccinations. Vaccines can help your immune system protect you from certain infections. While most people get vaccines as children, certain booster vaccines are needed periodically (Tdap, influenza, shingles) to help protect the body from future infections.
  • Getting enough sleep. Sleep deprivation and altering the circadian rhythm can impact the immune system and increase the number of inflammatory cytokines circulating in the body.
  • Getting regular exercise. Studies have shown that exercise helps decrease circulatory inflammatory chemicals and enhances vaccination responses. Animal research suggest that exercise may help prevent immunosenescence, also known as the aging of the immune system.

It’s been difficult to demonstrate a link between stress levels and immune system function. But studies have shown that people with higher stress levels have decreased response to vaccinations.

Other reviews also note that people with cancer who have chronic stress show decreased immune cell function, especially in response to cancer cells.

And as previously mentioned, both lack of sleep and poor eating habits can also negatively impact your immune system.

Reduced sleep and alterations in sleep rhythm can make your body more susceptible to bacterial and viral infections.

A 2015 study suggested people with short sleep duration and poor sleep continuity were more susceptible to the common cold. Research from 2012 also indicated that sleep deprivation may affect the body’s antibody response to vaccination.

A balanced diet with sufficient protein and micronutrients is essential to a well-functioning immune system.

You can find high value sources of proteins in foods like:

  • eggs
  • fish
  • lean meat
  • whey protein

Vitamin C, vitamin E, and carotenoids act as antioxidants and are found in foods like citrus fruits, peanut butter, and carrots.

Additionally, a diet rich in fiber is integral to gut health and immunity, while unsaturated fatty acids, especially sources of omega 3, like cod liver oil or fish, help limit inflammation.

Research doesn’t yet show clear support for adding supplements to help boost the immune system. But evidence shows that deficiencies in things like vitamin A, vitamin D, zinc, selenium, folate, vitamin C, vitamin B6, and vitamin B12 have a negative effect on the immune system.

Some studies have also advocated for using vitamin C in treating the common cold and critically ill people in intensive care units (ICUs).

The benefits of exercise don’t stop at improved cardiovascular health. Regular physical activity can also benefit your immune system.

Research from 2012 suggested daily exercise may help improve vaccination response, decrease levels of inflammatory chemicals, and increase T cell (a type of white blood cell) counts.

Findings also show that people who exercise regularly have fewer symptoms of upper respiratory tract infections.

People with weakened immune systems should take precautions to protect themselves from harmful pathogens that could cause infections.

For example, dietary recommendations include avoiding raw meat and fish, unpasteurized dairy, and unwashed fruits and vegetables. Ensuring your vaccinations are up to date is also important.

And if you plan to participate in activities, like swimming and hiking, consider talking with a doctor. You may also want to speak with a doctor before using cannabis, since there’s a risk of transmitting fungal infections like aspergillus.

Dr. Elizabeth Thottacherry is an ABMS board certified internal medicine physician specializing in infectious diseases. She’s a practicing physician at the University of Alabama at Birmingham Hospital.