Strengthening Your Immune System
How to maintain a healthy immune system
Reviewed by: Krystle Zuniga, PhD, RD, LD
Written by: Ashley Lawrence
Many of us already know that vitamin C benefits our immune system, and when we start feeling under the weather, we have a tendency to try to “boost” our immune system by increasing our vitamin C intake with glasses of orange juice or supplements like Emergen-C. While vitamin C does support various functions of the immune system, increasing intake won’t prevent you from getting sick, but it may reduce the severity and duration of your illness. Maintaining a healthy immune system provides strong defense against viral infections like cold and flu.
How can I support my immune system?
“Your immune system is more complex than just packing in some extra vitamin C into your diet,” explains UT Health Austin registered dietitian Krystle Zuniga, PhD, RD, LD. “You need to focus on the foundation that supports your immune system every day, and that foundation is made up of good nutrition, moderate exercise, stress management, and getting enough sleep. By maintaining this foundation, you can support your immune system’s optimal functioning, and a strong immune system is your best defense against infection and illness. Your immune system can become weakened through poor diet quality, lack of exercise, stress, and inadequate sleep.”
Diet
To strengthen your immune system, focus on a balanced diet high in nutrient-rich whole foods that provide adequate protein, vitamins, minerals, antioxidants, and other health-promoting compounds.
Protein
Protein provides amino acids that form the building blocks of all the cells in your body, including the cells that power your immune system.
Protein sources include:
- Meats and fish
- Low-fat dairy products (yogurt, milk, cottage cheese)
- Beans and legumes
- Soy products
- Nuts and nut butters
Vitamins
Vitamins support numerous biochemical reactions that help your body fight infection.
Vitamin sources include:
- Vitamin A: Orange and yellow fruits and vegetables (sweet potatoes, carrots, apricots, and bell peppers), dark leafy greens (spinach and kale), eggs, and fortified milk
- Vitamin B6: Meat (pork, turkey, and chicken), fish (salmon and tuna), dairy, pinto or garbanzo beans, avocados, and grains
- Vitamin C: Citrus fruits (oranges, grapefruits, and tangerines), strawberries, papaya, vegetables (spinach, kale, Brussel sprouts, and broccoli)
- Vitamin D: Fish (salmon, herrings, and sardines), egg yolks, fortified whole grain cereals, fortified orange juice, and fortified dairy products
Minerals
Minerals provide resistance to and the prevention of infection.
Mineral sources include:
- Zinc: Meat (beef and lamb), shellfish (oysters, shrimp, crab, and lobster), nuts and seeds, dairy, and dark chocolate
- Iron: Meat, fortified breakfast cereals, oysters, white beans, soybeans, lentils, spinach, tofu, and dark chocolate
Probiotics
Probiotics help your body maintain a healthy balance of beneficial bacteria in your digestive system.
Probiotic sources include:
- Yogurt or cottage cheese with live and active cultures
- Kefir
- Cultured vegetables (unpasteurized sauerkraut and kimchi)
- Tempeh or miso
- Kombucha
- Aged cheeses
Hydration
Hydration supports vital functions in your body and helps eliminate waste products. It is recommended that you drink 8-10 8oz glasses of water per day.
Take time to explore healthier eating habits.
Exercise
Moderate exercise helps reduce the risk of infection. Aim for 150 minutes a week (or 30 minutes a day, 5 days a week) of moderate-intensity exercise.
Challenge yourself to:
- Walk 2 miles
- Bike 5 miles
- Run 1.5 miles
- Swim laps for 20 minutes
- Do water aerobics for 30 minutes
- Jump rope for 15 minutes
- Walk stairs for 15 minutes
Here are some ways to stay active at home.
Stress Management
The stress hormone corticosteroid can suppress the effectiveness of the immune system by decreasing your body’s number of lymphocytes, which are the white blood cells that help fight off infection.
To prevent and relieve stress, try to:
- Practice positive thinking
- Stay connected to others
- Practice relaxation techniques, such as deep breathing, meditation, or yoga
- Exercise regularly
- Eat healthy, well-balanced meals
- Make time for hobbies, interests, and leisure activities
Learn how to cope with stress related to COVID-19.
Sleep
Getting a good night’s sleep helps your immune system find and destroy infected cells. The recommended amount of sleep is 7-9 hours each night.
You can develop better sleep habits by:
- Sleeping and waking at the same time each day
- Avoiding late-afternoon naps
- Putting away electronic devices 1-2 hours before bed
- Avoiding caffeine, nicotine, and alcohol 4 hours before going to bed
- Masking distracting noises with white noise or using ear plugs
- Regulating room temperature (60-67 °F)
- Exercising during the day