As winter approaches and we head into the cold and flu season (not to mention preventing COVID), it’s important to keep your immune system in tip-top shape. While a great deal of focus is on enhancing immunity, many people don’t realize there are also things that suppress your immune system that should be avoided. Here are a few things that can suppress the immunity:

Lack of exercise

Regular aerobic exercise helps blood move around your body more efficiently, so germ-fighting substances get where they need to go and help your body fight illness.

Not getting enough sleep

Sleep deprivation increases the likelihood of infection and viruses. During sleep, your body releases infection-fighting proteins, called cytokines, that support the immune system.

Low Vitamin D

Vitamin D boosts the immune system, so a deficiency can make you vulnerable to infection. Make sure to take a supplement, or eat eggs, fatty fish, and fortified foods like milk and cereal. Sunlight is another outstanding source.


Stress and anxiety take a major toll on the immune response and make it hard to fend off viruses. Find time each day for activities that support mindful relaxation.

Unbalanced Diet

Fruits and vegetables help the body make the white blood cells needed to fight off infections. If you’re not eating a balanced diet, your body may be lacking the vitamins, zinc, and other nutrients you need to stay healthy. Additionally, high fat diets can upset the balance of bacteria in your gut that support immune response.

Lack of Fiber

Fiber helps ward off chronic disease, lower inflammation, and improve gut health, which plays a primary role in immunity. Eating enough fiber every day (25 grams for women and 31 grams for men) supports the immune system. 

Not Getting Fresh Air

Spending time outdoors not only provides you with immunity-boosting Vitamin D, it also fights stress, which is linked to lower immune function.

Smoking and Alcohol

Smoking, vaping, and excessive alcohol consumption can weaken the body’s immune response and the ability of the body to repair itself.

A well-functioning immune system is critical to maintain good health. So, this fall and winter, protect your body from germs and viruses and avoid activities that suppress your immune system.

Authored by Zach Meeker, Research Assistant for Midwest Orthopaedics at Rush University Medical Center

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