Learning About Your Immune System

What does your immune system do?

The immune system is your body's natural defense system. It helps fight infections.

Your immune system is made up of antibodies, white blood cells, lymph nodes and vessels, and other chemicals and proteins.

The parts of the immune system work together to protect your body. They attack and destroy substances that are foreign to your body, such as bacteria and viruses.

Immunity

Immunity is how well you are protected from a disease. You may be born with short-term protection from certain diseases. Or you may be protected after you get an infection or a vaccine.

A vaccine helps your immune system make antibodies to fight a disease. Those antibodies will then fight the disease if you're exposed to it in the future. This helps keep you from getting sick. Or you may not get as sick.

What problems can it cause?

Your immune system can cause:

• Allergic reactions and allergies. These happen when your immune system overreacts to something that usually doesn't harm you. For example:
  • Pollen. When some people breathe in pollen, their immune system attacks it. This causes allergy symptoms such as hay fever.
  • Medicine, chemicals, food, insect bites, or other things. An overreaction can range from mild to deadly.
• Autoimmune diseases. These diseases happen when your immune system acts like some of your own tissues are foreign substances. The body makes antibodies and other cells that attack and destroy your tissues. These diseases include lupus and rheumatoid arthritis.

Things that can weaken your immune system

• Substance use disorder
• Withdrawal from alcohol or drugs
• Certain health problems, including diabetes, cancer, HIV/AIDS, and autoimmune diseases
• Chemotherapy or radiation
• Some medicines, such as corticosteroids
• Medicines that control the immune system
• Not having a spleen
• Stress

How can you help?

You may be able to help your immune system by having a healthy lifestyle. Make sure to:

• Get enough sleep. How long you sleep is not as important as how you feel when you wake up. If you do not feel refreshed, you probably need more sleep.
• Eat heart-healthy foods. These foods include vegetables, fruits, nuts, beans, lean meat, fish, and whole grains. Limit sodium, alcohol, and sugar.
• If you smoke, vape, or use other tobacco or nicotine products, try to quit. If you need help quitting, talk to your doctor about quit programs and medicines. These can increase your chances of quitting for good.
• Limit alcohol to 2 drinks a day for men and 1 drink a day for women. Too much alcohol can cause health problems. Talk to your doctor if you have questions about how much alcohol you can drink.
• Take steps to control your stress and workload. Learn things to help you relax, like meditation.
• Manage any health problems you have. For instance, if you have diabetes, try to keep your blood sugar in your target range.