Do These Immune Boosters Actually Work?

About Nicole Pajer

Nicole Pajer is a Los Angeles-based freelance published in The New York Times, Woman's Day, AARP, Parade, Wired, Glamour, People and more.

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Cold and flu season is just around the corner. When you head to the grocery store, you’ll notice vendors are starting to pack end caps with superfood supplements. High dose Vitamin C, elderberry, echinacea… does any of it work? Here are a few helpful things to consider about these so-called immune boosters and whether they may be able to help you to fight off viruses this fall.

1. Vitamin D

A 2017 study found that Vitamin D can offer some help to protect against acute respiratory infections, finally putting some research behind the age-old advice of “make sure you’re getting enough Vitamin D.” Prior to the 2017 study, some other observational studies over the years previously linked low Vitamin D levels to a higher chance of getting respiratory infections. The 2017 research, conducted by Queen Mary University of London, indicated that daily or weekly Vitamin D supplementation had a more significant impact than those who took it monthly – and the study reported that those taking daily or weekly supplementation had their risk of respiratory infection cut in half.

You can also catch some Vitamin D by getting outdoors (but make sure to practice good sun safety, like avoiding direct sunlight between 10am and 4pm, when the sun’s rays are the strongest and wearing sunscreen for prolonged exposure). Vitamin D is also available in some foods like fortified milk and cereal and fatty fish like salmon. Talk to your doctor about the best way for you to obtain Vitamin D based on your personal history – i.e. how much dosage to take if you supplement or if you can get enough from food. Your dermatologist can also weigh in on how to go outdoors and get exposure to Vitamin D while keeping your skin safe.

2. Zinc

The jury is still out on this one. Some studies suggest that zinc may shorten the duration of the common cold, while other studies indicated that supplementing with zinc didn’t have any effect. And some research found that while zinc may help, it can also lead to side effects like leaving a bad taste in your mouth and nausea. It’s also important not to overdose and make sure to stick to the 40mg a day recommended maximum. Before relying on zinc, if you come down with a cold or flu, ask your doctor if they’d recommend taking it.

3. Echinacea

First off, what exactly is echinacea? It’s a flowering plant from Northern America that has a rich history of being used in medicine. Like Zinc, however, it’s unclear as to whether this is the immune booster it’s touted as. Some studies have suggested that echinacea can help to increase the body’s white blood cell count, which is typically essential for fighting infections. Other studies indicated that it didn’t do anything to ward off the common cold. Echinacea can have some potential side effects, the most common being an upset stomach. Other things to look out for with echinacea include rashes, worsening of asthma symptoms or, in extreme (and rare cases), trouble breathing. Ask your doctor before giving it a whirl.

4. Elderberry

When cold and flu season hits, elderberry infused gummies and concoctions get prominent placement on supermarket shelves. But do these really give your immune system the boost that they claim to? Two studies suggested that elderberry extract supplements knocked an average of four days off of the duration of the flu, when compared to a placebo. But the largest study to date on elderberry and the flu showed no actual added benefits of using elderberry to treat influenza versus a placebo. And some other research suggested that it may be able to help with symptoms like runny nose, congestion and cough. Thus, there’s conflicting research on the topic and experts note they need additional research before it can be confirmed as an immune booster.

5. Vitamin C

Research indicates that taking vitamin C daily generally does not help to prevent you from getting a cold or flu. But some evidence suggests that if you take it at the onset of an illness that it may be able to shorten the duration of symptoms. Talk to your doctor about which supplement and what dosage to take. You can also get vitamin C in your diet by eating peppers, oranges, grapefruit, kiwi, broccoli and tomatoes.

6. Garlic

The short answer is yes, garlic contains properties, called allicin, that can help the immune system to do its thing. Some studies have indicated that garlic may be able to reduce the risk of getting sick and reduce how severe symptoms are. Research is lacking, however, on how often you’d need to take garlic, whether that’s daily or just when symptoms arise. Crushing or slicing garlic before you eat it helps to maximize the allicin content, furthering its immune-boosting properties. You can add garlic to foods that you make, shake some powdered garlic over food, infuse food with garlic oil or take garlic supplements. Ask your doctor before supplementing to see if it's a safe option for you and to advise on a dosage, as too much garlic in the supplemental form can be toxic.

7. Probiotics

Ever heard the saying all health starts in your gut? Probiotics are healthy bacteria that go right into your digestive tract. Some studies have suggested that taking them may help to ward off the common cold, but only to a modest degree and experts warn that further studies need to be done before being able to definitively claim that. Probiotics are generally considered safe, but some people may react differently to them. This tends to be the case mainly in people with severe illnesses or compromised immune systems. Talk to your doctor before taking a probiotics supplement and ask for a referral on which brand and strains to take.

8. Green tea

Research is still being done, but some studies have linked green tea to having some immune-boosting properties. This means it may have some properties that may help to ward off the common cold or flu. In addition to being packed with antioxidants, green tea is anti-inflammatory, making it a great choice as a fluid to sip while under the weather. It does, however, contain a small amount of caffeine (around 30-50mg per cup) so keep that in mind before reaching for a cup before bed.

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