Boost your Immune System

Your immune system is your body’s first line of defense against foreign invaders like germs and viruses. Your lifestyle habits may help or harm it.

A look inside your immune system

Your immune system helps protect against foreign invaders to prevent infection and disease. It also helps you recover after an illness or injury.

What makes up the immune system?

Blood and lymph help carry and transport the other elements of the immune system. White blood cells (also called leukocytes) help fight off the foreign invaders. There are two main types:

• Phagocytes move through the blood vessels and tissue to eat up foreign invaders. The most common type is a neutrophil.
• Lymphocytes help the body recall and recognize former invaders and help destroy them. There are two types of lymphocytes: B-cells and T-cells. B cells seek out targets and create antibodies to lock onto them. T-cells destroy the antigens that the B-cells have identified.

Help keep your immune system healthy

Following general good-health guidelines can help you give your immune system the upper hand.

Eat a healthy diet

Good nutrition is a key element of a healthy immune system. Help give your immunity a boost with the six important nutrients listed below.²

Nutrient	Sources
Iron	Lean meat, beans, nuts, and fortified breakfast cereals
Vitamin A	Orange and red fruits, carrots, apricots, and bell peppers
Vitamin C	Citrus fruit like oranges, grapefruit and tangerines, red bell pepper, papaya, strawberries, tomato juice and fortified foods
Vitamin D	Sunlight, fatty fish, egg yolks, and fortified dairy
Vitamin E	Seeds, nuts, vegetable oils, and peanut butter
Zinc	Lean meat, whole grains, milk, seeds and nuts2

Exercise regularly

Exercise can contribute to good health and therefore to a healthy immune system.³ There are several theories about how exercise may affect the immune system, but none has been proven.⁴

• Exercise may help flush bacteria out of the lungs and airways, which may reduce your chance of coming down with a cold, flu or other illness.
• Exercise causes antibodies and white blood cells to circulate more quickly so that they can detect illnesses earlier than they might have before.
• Exercise causes a brief rise in body temperature that may prevent bacteria from growing and/or help the body fight infection better.
• Exercise slows the release of stress hormones; lower stress hormones may offer a protective effect.

Manage stress

Chronic stress can have a negative impact on the immune system, and older adults may be more prone to stress-related immune changes.⁵

Help manage stress with the 4 As.

• Avoid stress by planning ahead and taking control of your surroundings.
• Alter your situation for the better.
• Accept things the way they are.
• Adapt your expectations or standards to help you cope.⁶

Get plenty of sleep

Not getting enough sleep may make you more likely to get sick after being exposed to a virus and affect how quickly you recover from an illness.⁷ A lack of sleep may decrease the production of important immune system proteins called cytokines, as well as infection-fighting antibodies.

Practice these good sleep habits:

• Be consistent by going to bed at the same time each night and waking up at the same time each morning.
• Keep your bedroom cool, dark and quiet.
• Remove electronic devices like TVs, computers, smartphones and tablets from the bedroom.
• Avoid large meals, caffeine and alcohol before bed.
• Get some exercise during the day.⁸

If these strategies don’t help, talk to your healthcare provider.

Stay up to date with immunizations

According to the CDC, vaccination is one of the most convenient and safest ways to prevent a variety of illnesses.⁹

Talk to your healthcare provider to learn more about these vaccines and how often you need them:

• Influenza (flu)
• Pneumonia
• Shingles
• Tdap (tetanus, diphtheria and pertussis)

Practice good personal hygiene

Following some simple personal hygiene habits may help keep bacteria, viruses and illnesses away.

To minimize your risk of infection:

• Wash your hands with soap and water before preparing food and after using the bathroom.
• Cover your mouth and nose with a tissue when you sneeze or cough, or cough into your elbow rather than your hand.
• Wash and bandage all cuts. If the wound is serious, be sure to have it examined by your healthcare provider. Also, don’t pick at healing wounds or blemishes because it may allow germs to enter.

Don’t share dishes, glasses or eating utensils. Avoid having direct contact with items like napkins, tissues and handkerchiefs that have been used by others.¹⁰

Interested in learning more? Visit www.HumanaNeighborhoodCenter.com to register for live and on-demand health education classes.

This is for informational purposes only and does not replace treatment or advice from a healthcare professional. If you have questions, please talk with your doctor. Talk to your doctor before beginning an exercise program or making any changes to your diet.

Sources

1. “Immune System”, Nemours Foundation, Last accessed May 22, 2025, http://kidshealth.org/en/parents/immune.html
2. “Support your immune function with good nutrition“, Mayo Clinic Health System, Last accessed April 25, 2023,  https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/support-your-immune-function-with-good-nutrition
3. “How to Boost Your Immune System”, Harvard Health, Last accessed April 25, 2023, https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system 
4. “Exercise and Immunity”, National Library of Medicine, Last accessed April 25, 2023, https://medlineplus.gov/ency/article/007165.htm
5. “Stress effects on the body”, American Psychological Association, Last accessed April 25, 2023,  https://www.apa.org/research/action/immune.aspx
6. “Stress management”, Mayo Clinic, Last accessed April 25, 2023, http://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-relief/art-20044476?pg=2
7. “Lack of sleep: Can it make you sick?”, Mayo Clinic, Last accessed April 25, 2023, http://www.mayoclinic.org/diseases-conditions/insomnia/expert-answers/lack-of-sleep/FAQ-20057757
8. “Tips for Better Sleep”, Centers for Disease Control and Prevention, Last accessed April 25, 2023, https://www.cdc.gov/sleep/about_sleep/sleep_hygiene.html
9. “There Are Vaccines You Need as an Adult”, Centers for Disease Control and Prevention, Last accessed April 25, 2023, https://www.cdc.gov/vaccines/adults/index.html
10. “How to prevent infections”, Harvard Health, Last accessed April 25, 2023, https://www.health.harvard.edu/how-to-prevent-infections