The Top 6 Supplements You Didn’t Know Support Immunity

The Top 6 Supplements You Didn’t Know Support Immunity

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by Krista Russ
February 17, 2023

Although it may seem like we are finally getting some respite from COVID-19, Americans are actually in the worst cold and flu season yet, according to The New York Times. For instance, R.S.V (respiratory syncytial virus) has led to pediatric hospitalizations at a record high. The flu usually peaks around February, but influenza hospitalizations are the highest they’ve been in over a decade. And while Covid-19 rates are lower than they have been the previous two winters, those rates are rising too, leading many to call this period a “tripledemic”. 

Given the surging rates of respiratory illness, it’s a good idea to do everything you can to bulletproof your immune system. Part of that equation includes healthy lifestyle choices like healthy diet, sound sleep, and regular exercise to help strengthen your natural defenses. In addition, there is evidence that certain supplements (i.e – vitamins, antioxidants, minerals, and other biological compounds) may further bolster your immune system. 

Below, we’ve compiled a list of six supplements you should keep stocked this winter to boost your body’s natural defenses. Here are the top six immune-boosting supplements you may have not known about. 

Vitamin C

Vitamin C is not only a major antioxidant that stamps out cell-damaging molecules called free radicals, but it also supports immune cells. For example, it aids a process called apoptosis (cell death) that kills old, used cells so that the body can make new cells that are better equipped to handle illness. 

Studies show that Vitamin C supplementation can reduce the length and severity of upper respiratory tract infections like the common cold and flu. 

You can get vitamin C from foods like citrus fruits, broccoli, strawberries, and potatoes. 


The mineral zinc affects the expression of hundreds of genes that control immune cells according to a 2009 study. Zinc acts as a signaling molecule for immune cells and regulates other signaling molecules involved in the immune response. 

Zinc also aids in wound healing and regulates the inflammatory response, an important component of immunity. Like Vitamin C, zinc has also been demonstrated to shorten the duration of colds (per Mayo Clinic). 

Food sources include clams, shellfish, meat, whole grains, and nuts.

Vitamin D

When you think of Vitamin D, you probably think of the sunshine vitamin imperative for healthy bones, and although this is true, you might be surprised to learn that Vitamin D does much more than this. In fact, Vitamin D is not technically a vitamin at all; it is a hormone (via You and Your Hormones). Both Vitamin D produced in response to sunlight and absorbed from food is converted by the liver and kidneys into its active form, a hormone called calcitriol

Researchers are now beginning to understand Vitamin D’s important role in immune function. For example, Vitamin D regulates the innate and adaptive immune responses (per SOLIUS). The innate immune response is your body’s frontline against foreign pathogens and includes barriers like your skin and mucous membranes. Vitamin D regulates this response by interacting with receptors on your immune cells. 

Food sources are limited but include eggs, cold water fish like salmon and sardines, and fortified milk and dairy products. For this reason, supplementation is often needed for optimal health. 


Melatonin is a hormone produced by the pineal gland in the brain that controls the circadian rhythms and regulates the body’s sleep/wake cycle. For this reason, it is often used to treat sleep-related conditions like insomnia and jet lag, but it also functions as a potent antioxidant that plays a key role in the immune system. 

Like Vitamin D, melatonin enhances both innate (your body’s non-specific immune response that includes barriers like the skin and mucous membranes) and cellular immune response (includes specialized immune cells like neutrophils and macrophages) according to a 2005 paper

Melatonin also triggers the creation of T-cells, which are specialized immune cells that kill infected host cells and recruit other immune cells to the site of infection. It does this in part by increasing phagocytosis, a process by which white blood cells (aka leukocytes) “eat” pathogens and other cellular debris.

Food sources include tart cherry juice, walnuts, goji berries, and mushrooms, though supplements contain a more precise dosage. 


Glutathione is considered the “mother of all antioxidants” with vital functions when it comes to both the immune system and general health. This tripeptide is produced in cells and built of three key amino acids: glutamine, glycine, and cysteine (via Healthline). It also recycles other antioxidants like Vitamin C, E, CoQ10, and alpha lipoic acid. 

Chronic health conditions, aging, stress, and poor nutrition can all cause glutathione deficiency by making the body deplete its natural stores more rapidly. Glutathione supports many different types of immune cells such as mast cells and lymphocytes and helps to arrest the inflammatory response by regulating cytokine production. Cytokines are proteins that white blood cells use to “talk to” other immune cells.

You can help your liver make more glutathione by consuming foods rich in the sulfur like cruciferous veggies (broccoli, cauliflower, Brussels sprouts, and kale), eggs, and allium-rich veggies like onions and garlic, or you can supplement for a more bioactive dosage. The herb milk thistle can also boost its production, as well as green tea. 

N-acetyl-cysteine (NAC)

N-acetyl-cysteine or NAC, a sulfur-rich amino acid that is vital to producing glutathione, according to Mount Sinai. In addition to increasing glutathione production, NAC itself acts as an antioxidant, helping the liver detoxify free radicals

NAC reduced the severity of colds when study participants took 600 mg twice a day for six months over a placebo. It has also benefited other immune related conditions such as Acute Respiratory Distress Syndrome–a potentially dangerous COVID complication–and HIV/AIDS patients, in which its inclusion in a supplement regimen helped increase glutathione production and allowed patients to gain more weight in a small, 12-week study. While more research is needed, this research certainly shows NAC’s potential to benefit a variety of immune related conditions.  

While you can’t get NAC from food directly, you can help your body make more of it by eating sulfur-rich foods. The same foods that boost glutathione production like broccoli and garlic also boost NAC production, offering a double bang for your buck. 

How Do I Get The Most From These Supplements?

Remember to always speak with a healthcare provider before taking any supplements to ensure they are appropriate for you and don’t interact with any drugs you may be taking. While you should follow the supplement’s bottle/box instructions for general dosage guidelines, for a more customized dosage and best form (i.e- pill, powder, liquid, etc.) that aligns with your personal health goals, we encourage you to Find an APIM | WLM Trained Provider today. This step is particularly important because the effectiveness of a supplement is largely based on its dosage and form, which can only be determined by seeing a trained provider who understands this in relation to your personal health conditions and goals. 

For instance, some forms of vitamins or minerals are far more bioavailable in the body than others, so this can help you avoid wasting time and money on forms that may be less suitable for you. Also, not all brands are created equally. Some brands may offer a higher quality supplement with better absorption over another brand, for instance. Testimonials, reviews, and research into the supplement company and their practices can provide invaluable insight into the quality of their products. For example, do they perform third party/quality control testing to verify their ingredients are active and efficacious? Are they GMP certified or do they hold other certifications that indicate a superior product? These are all important factors to consider as a consumer. 

To reap the optimal benefits of these six supplements, it’s important that you know how they work, specific conditions they may help, important considerations such as situations that may increase their need, and forms that may be better absorbed over others. You’ll gain all of this exciting insight and more by downloading our Guide To Fortifying Your Immune System today.


Walker A. Just How Bad Is the ‘Tripledemic’? The New York Times. December 16, 2022. Accessed December 16, 2022. 


Kubala J, Meeks S. The 15 Best Supplements to Boost Your Immune System Right Now. Healthline. Updated April 19, 2021. Accessed December 16, 2022. 


Haase H, Rink L. The immune system and the impact of zinc during aging. BMC: Part of Springer Nature. June 12, 2009. Accessed December 16, 2022. 


Zinc. Mayo Clinic. November 17, 2020. Accessed December 16, 2022.,meat%20and%20fortified%20breakfast%20cereals

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