How to Boost Your Immune System After the Flu: Your Top Questions Answered

Co-authored by David Nazarian, MD and Hannah Madden

Last Updated: August 25, 2021 References

Dealing with the flu is always an unpleasant experience—thank goodness you’ve recovered! Boosting your immune system can help your body fight infections off in the future so you (hopefully) won’t have to deal with the flu again for a while. Thankfully, boosting your immune system only requires a few small changes to your daily life, so you can recover from your illness and increase your immune system in no time.

Question 1

Question 1 of 12:
How can I boost my immune system quickly?

1
Get enough sleep to let your body rest. Sleep helps your body rest and recover, especially after you’ve been sick. Try to get at least 8 hours of sleep every night, and stick to a regular sleep schedule to repair your immune system.^{[1]
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- You probably slept a lot when you had the flu, which is great! You might feel more tired or lethargic as you recover.
2
Eat a balanced diet to maintain your nutrient levels. Try to incorporate fruits, vegetables, legumes, proteins, and healthy fats into your daily meals.^{[2]
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David Nazarian, MD
Diplomate, American Board of Internal Medicine
Expert Interview. 26 March 2020.} Your appetite might be a little lower than usual as you recover from the flu, so make your meals count by eating right.^{[3]
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3
Exercise regularly to stay healthy. Try to do 30 minutes of moderate exercise per day to help boost your immune system and your overall health. ^{[4]
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David Nazarian, MD
Diplomate, American Board of Internal Medicine
Expert Interview. 26 March 2020.} Take it slow if you’re still recovering from the flu by jogging, walking, or doing yoga.^{[5]
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Question 2

Question 2 of 12:
What lowers your immune system response?

1
High stress levels can weaken your immune system. Try meditating, doing yoga, writing in a journal, or practicing self-care to boost your immune system and feel better overall.^{[6]
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Harvard Medical School
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- Lowering your stress levels looks different for everyone, so don’t be afraid to try out a few different methods.
2
Smoking can disrupt the balance of your immune system. If you are a heavy tobacco smoker, it may be lowering your immune system’s ability to fight infections. Try to cut back or stop smoking to increase your overall health.^{[7]
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3
Certain medications can temporarily weaken your immune system. This is especially common in medication to treat cancer or right after an organ transplant. If you’re taking any of these medications, talk to your doctor if you get sick.^{[8]
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Question 3

Question 3 of 12:
Does Vitamin C help your immune system?

1
Yes, eating Vitamin C is one of the best ways to boost your immune system. Incorporate oranges, grapefruits, tangerines, strawberries, bell peppers, spinach, kale and broccoli into your diet to get enough Vitamin C.^{[9]
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- Your body doesn’t produce or store Vitamin C on its own, so it’s important to have some every day.
- Try to get about 64 to 90 mg of Vitamin C per day.
- It’s not really possible to get too much Vitamin C via fruits and veggies. However, if you’re taking supplements, too much Vitamin C can cause nausea, vomiting, and diarrhea.^{[10]
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Question 4

Question 4 of 12:
Which vitamins help boost your immune system?

1
Vitamin B6 can help your immune system. It supports the biochemical reactions that your immune system uses to fight infections. Eat chicken, salmon, tuna, green vegetables, and chickpeas to get enough Vitamin B6.^{[11]
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- Try to eat about 1.6 mg of Vitamin B6 per day.^{[12]
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2
Vitamin E helps fight off infection. It’s a powerful antioxidant that can assist your immune system. Try to eat nuts, seeds, and spinach for your daily dose of Vitamin E.^{[13]
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Cleveland Clinic
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- Try to get around 15 mg of Vitamin E per day.^{[14]
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Question 5

Question 5 of 12:
Which drinks help boost your immune system?

1
Water is the best drink for your immune system. Water helps carry your immune system cells around your body to fight off infections.^{[15]
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David Nazarian, MD
Diplomate, American Board of Internal Medicine
Expert Interview. 26 March 2020.} Without water, your immune system can’t function at its full capacity, so make sure you’re drinking around 8 glasses per day.^{[16]
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- Stay away from dehydrating liquids like coffee and alcohol.
- Try keeping a water bottle with you so you can take a drink anytime you’re thirsty.

Question 6

Question 6 of 12:
Which foods help boost your immune system?

1
Fruits and vegetables are great for your immune system. Fruits and veggies contain vital nutrients that are important for your immune health. Try to eat 4 servings of vegetables and 5 servings of fruit per day to get all the nutrients that you need.^{[17]
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- Getting vitamins and minerals through fruits and veggies is much better than taking supplements.

Question 7

Question 7 of 12:
Which food and drinks weaken your immune system?

1
Processed foods don’t give you enough nutrients. While they may not “weaken” your immune system, they don’t do you any favors, either. Empty calories will fill you up without adding any nutrients to your body.^{[18]
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- Processed foods usually come in a package and have long shelf-lives.
2
Alcohol can weaken your immune system. Studies have shown that large amounts of alcohol can kill the healthy bacteria in your gut, which can have an adverse effect on your immune system. If you’re going to drink alcohol, try to do it in moderation, especially if you’re recovering from the flu.^{[19]
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- Alcohol also dehydrates you, which can lower your immune system.

Question 8

Question 8 of 12:
Are there supplements to boost your immune system?

1
Yes, but it’s better to get vitamins from food than supplements. Vitamin C, E, and B6 are all available in supplement form. However, your body absorbs them better when they come from actual food. If you can, try to get everything you need from fruits, vegetables, and protein.^{[20]
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Cleveland Clinic
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- If you think you’re vitamin-deficient, talk to your doctor before starting a supplement.
- If you are taking a supplement, follow the dosage directions carefully. Taking too much can lead to vomiting, nausea, and diarrhea.
- If you can’t eat a balanced diet, try a multivitamin.^{[21]
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Question 9

Question 9 of 12:
Does getting the flu make your immune system stronger?

1
No, not necessarily. Getting the flu protects you from that strain of the flu in the future. It doesn’t necessarily make your immune system “stronger,” but it does provide your body with the antibodies it needs to fight off that flu later on. It’s kind of like getting the flu shot, except you got the actual flu.^{[22]
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- However, if you encounter a different strain of the flu, you might still catch it. Antibodies are only good for one strain, not multiple.

Question 10

Question 10 of 12:
What are some signs of a strong immune system?

1
You probably don’t get sick often. When your immune system works well, it’s able to fight off infections right away. If you only get sick once or twice a year, you probably have a strong immune system.^{[23]
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2
You might be able to fight off colds quickly. When you do get sick, you’re probably only experiencing symptoms for about a week. This shows that your body is actively fighting off the infection the entire time.^{[24]
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- Getting a cough or a runny nose are actually signs that your immune system is working.

Question 11

Question 11 of 12:
What happens if your immune system is weak?

1
You might get sick fairly often. Your immune system fights off infections. If it can’t do that, you may have recurring issues with flus, colds, or other severe infections.^{[25]
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Mayo Clinic
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- While it does vary widely, most people get sick 2 to 4 times per year.
2
You may have some digestion issues. Cramping, loss of appetite, vomiting, and nausea are all common with weakened immune systems. The bacteria in your gut play an important role in immune system health; when they’re out of whack, it can lower your immune system.^{[26]
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3
You could experience stunted or delayed growth. This is often a sign of a weakened immune system in children. If your child is short or small for their age, it could be a sign that their immune system isn’t working correctly.^{[27]
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- Delayed growth can be a symptom for a number of things, so you should talk to your doctor for a diagnosis.

Question 12

Question 12 of 12:
How can you test your immune system strength?

1
Ask your doctor for a blood test. They can check the levels of immunoglobulin in your blood. They can also look at the number of blood cells and immune system cells you have in your blood. If any of these are abnormal, you may have a weakened immune system.^{[28]
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Mayo Clinic
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- Doctors usually use blood tests like these to test for immunodeficiency.
2
Use prenatal testing on a fetus. If you have a child with an immunodeficiency, your doctor can test your amniotic fluid to see if your fetus has any issues with it as well. In some cases, they may also test your DNA.^{[29]
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Mayo Clinic
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- Immunodeficiency can be genetic, which is why you’d want to test your future child.