How to Boost Immune System When Sick with a Cold or Flu

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With the winter coming up, people are naturally looking for fast ways to boost their immune system using supplements and foods. Fortunately, nature provides us with some powerful ingredients which can give improve your immune system and prevent you from catching those bugs.

To get the most out of these compounds, you should make sure that you are getting all the recommended nutrients in your diet. One of the reasons people often get sick is because they have a lowered immune system from a poor diet. Correcting deficiencies will normalize immune function, which is great! But below are some ways to put your immune system on high alert so it acts faster in the presence of pathogens.

Looking For a Fast Way To Boost Your Immune System?

If you feed your body all the essential nutrients, and you have good sleeping habits, then you’re already going to do a lot better in fighting off these bugs. You can further protect yourself by incorporating a few different foods and supplements into your diet. I always recommend having these at hand all times of the year, but you should at least make sure you have them ready for the winter when you’re most likely to get sick.


Fast way to boost immune system using garlic

Garlic is a great ingredient that can be added to many different foods and has many health benefits, not just the immune system boosting effects. Garlic’s man active component is called allicin, which is created when the cloves are crushed and alliinase reacts with alliin.

When using garlic, I recommend that you crush the garlic and leave it for a few minutes, and then consume it with something. From my experience, when I felt I was developing a scratchy throat (sign of a cold), I crushed at least 4 cloves of garlic and spread it on some bread with some olive oil. It can be strong, so be careful not to burn your mouth! But it’s very effective.

If you don’t fancy smelling of garlic by eating them all day, you can additionally take one capsule of Allicin per day which is equivalent getting the same amount of allicin as you’d get by eating 25 cloves of garlic, but now without the smell. One study showed that these capsules reduced the incidence of colds and significantly improved recovery time.

Garlic is one of the best natural remedies to boost your immune system and cure early-stage infections, but not effective for colds if the infection has gone too far. There are many studies published on the antimicrobial effects of garlic and allicin on PubMed for the prevention and treatments of bacterial, viral, and fungal infections either alone or in combination with antibiotics.

If there is one food or supplement I’d recommend everyone take, or have close at hand, it’d be garlic.

Other benefits: garlic lowers blood pressure, reduces AGE’s, lowers glucose, improves the gut by altering gut bacteria (which is also part of our immune system).


Ginseng is a fast way to boost immune systemGinseng has been touted to have many medicinal properties. It’s a treatment that has been used for many years for colds and flu in countries like Korea and China. North American Ginseng appears to be the most powerful in the treatment of acute respiratory infection.

Studies have found that this common herb can significantly shorten the length of colds by 6.2 days, and the best effect is when it’s taken preventatively for two to for months.

Ginseng reduced the number of colds by around 25% in five trials examining the effects of North American Ginseng (Panax quinquefolius).

Tips: Ginseng can be added to hot water to make ginseng tea, add to smoothies. It’s available in many different forms.

Other benefits: Helps boost metabolism to lose weight, increases stamina, and lower blood sugar.


Green tea is a quick way to boost immune system

Green tea is one of my favorite drinks. There’s an old Chinese proverb which says: “Rather three days without food than a day without tea”. I think drinking tea has almost become a ritual for me. First thing I do in the morning makes a cup of green tea.

Green Tea contains many different compounds or polyphenols which promote health. Two of the main components in helping boost the immune system are EGCG and L-Theanine. Studies suggest that the compound EGCG directly inhibits entry and replication of viruses like the common cold, influenza, and others. Tea primes the immune system so it can more quickly fight off infections before they have a chance to take hold.

Tips: Add some ginger and lemon to your tea to make even better. Citrus fruits may boost the benefits of drinking green tea and ginger contains gingerols which help block inflammation, and also decrease nausea, which some people get from the tannins in green tea. Adding Manuka Honey to the tea is also a great idea if you have a bad throat and want to prevent bacterial throat infections. Gargling the tea might be more effective in preventing infections.

Other benefits: Boosts metabolism for weight loss, protects against diabetes, high cholesterol, high blood pressure and more. In a study from Japan, researchers found that drinking 5 cups of green tea or more reduced all-cause mortality for women by 23% for Women and 12% for Men.


Mushrooms can boost immune system fast

There are many different types of mushrooms, but Shiitake mushrooms have proven to be one of the most powerful in boosting immune function. Mushrooms contain Beta Glucans which stimulate parts of the immune system as well as decrease the level of inflammation in the body.

They help us to better fight for viral and bacterial infection. Shiitake mushrooms boost natural killer cells which destroy abnormal cells, whether they are cancerous or been infected and viruses.

In a randomized study looking at human immunity with the consumption of mushrooms, researchers noted significant and beneficial changes in the immune system after just consuming 5 to 10 g of mushrooms daily. If you don’t like Mushrooms, you can alternatively take a Beta Glucan Supplement.

Beta Glucans have been studied for years looking at its immune system modulating effects, and to date, there have been over 6000 studies published looking at prophylaxis and treatment of infectious disease (read about some of them here).

A trial involving 162 people, researchers gave participants of the study beta glucan and found that people in the treatment group experienced 25% fewer colds.

Tips: Don’t continually take the supplement. I recommend that you take a beta glucan supplement or consume mushrooms intermittently. So consider taking the supplement during times when you’re stressed, lack sleep, or surrounding by sick people. There is some evidence that some of the immune system benefits/changes decrease with continued use.

Other benefits: May lower cholesterol, lower risk of cancer, and well being in general. Mushrooms also provide vitamin D.


Elderberry can be used to help support a healthy immune system and protect you from developing colds. Elderberries contain anthocyanins which are strong antioxidants that help block free radical damage in the body. Studies have shown that elderberries are anti-inflammatory and immunostimulatory.

In 2016 a study was published looking at the development of colds and cold duration in Air-Travellers. The study was a randomized, double-blind, placebo-controlled clinical trial and it confirmed previous findings that this fruit protects against colds and reduces cold symptoms. The placebo group had a much longer duration of symptoms compared to the treatment group (117 vs 57, p = 0.02). Symptom score was also significantly higher in the placebo group vs treatment (583 vs 247, p = 0.05).

Tips: Use Elderberries in jams, sweets, pies and other foods. Do not eat them Raw! You can alternatively get some Gummies, which also contain vitamin A, C, D, E and Zinc for an improved immune system.

These are just some of the things you can do to boost your immune system, but of course, there are many more. Below I’ve listed a few posts so you can learn more about how to enhance your immune system to protect yourself from becoming sick whether it be from viruses, bacteria, a fungal infection. Or even cancer and autoimmune diseases. Without our immune system, we wouldn’t last long at all. If you want to live to a very old age, your immune system is something that you have to keep healthy. You have to slow down the immune system from aging or else you would die of illnesses such as pneumonia and other common infections.

See related posts on The Immune System

  1. Enhancing Your Immune System
  2. Fasting Rejuvenates The Immune System
  3. Intermittent Fasting With Valter Longo, Ph.D. Interview 
  4. Probiotics and Immunity
  5. Probiotic helps digestive health

Reviewed and updated: 08/2018

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  • Hello, thanks for your great and longsighted blog, However, I have some doubts about green tea consumption, in particular when combined with calorie restriction. Both caffein and L-theanin act on the central nervous system, and regular consumption will create substance-related and psychological addictions; so although these substances are supposed to increase short term performance in cognitive tests, on the longer run the brain may forget how to work on its own without these substances, and actually get weaker.

    Also, Caffein, L-theanin and EGCG are all supposed to prevent diseases like Alzheimer’s or cancer. But then the question in my opinion is, how such diseases are created in the first place, and often one possible cause seems to be carbohydrate- or calorie-rich nutrition, the opposite of low-carb diets and calorie restricted diets. For example, a 2012 study on roundworms Caenorhabditis elegans says: “Both caffeine and bacterial deprivation extended life span when applied to worms independently, but did not produce an additive increase when combined at either 15°C and 20°C”. So caffeine did not help extend the life span, if the worms are already calorie restricted by depriving them of bacterial-rich food.

    Or for another example, looking at a recent news story, according to which a study “shows that in mice black tea alters energy metabolism in the liver by changing gut metabolites” Again, we should be skepitcal, since the mice in the experiment were always fed a “high-fat/high-sucrose diet”, the opposite of a calorie restricted diet.

    So my guess is, if calorie restricition is already implemented, regular green tea consumption may have no, or even detrimental effects.

    • Thank you for your comment Nikolaus. I think being skeptical about mice studies in general is a good idea when it comes to food and supplements. There’s more I have to say about this and will respond to your comment properly this weekend. 🙂 Cheers!

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