Our immune systems
The immune systems is made up of intricate networks of protective, preventative, and defensive compounds. These little soldiers might be microscopic in nature, but are nonetheless working overtime to keep unwanted pathogens, bacteria, fungi, and viruses from disrupting our health and our lives.
There are 2 types of immunity:
- Innate immunity. This is the immunity that we’re born with. Innate immune cells are non-specific, meaning that they can and will attack any type of invader to the best of their ability.
- Adaptive immunity. This is the immunity we acquire over time. When a new invader attacks, our own cells differentiate (or transform) into cells that can fight off specific invaders. They may be strong enough to give us lifelong immunity (think of chickenpox) or they may only last a season or two (we’re looking at you cold and flu).
It’s not always an easy battle. There are germs everywhere, all the time. That’s why we have to equip our immune systems with the best of the best.
Vitamin C
Vitamin C is a classic key player in a properly functioning immune system as it prevents illness and shortens the period of symptoms if you do get sick. While we’re pretty clued in on the importance of vitamin C, we may not know the why and the how behind its powers.
First, vitamin C is a powerful antioxidant. This means that it protects us from free radicals, or unstable atoms that can wreak havoc on our cells.
Vitamin C is also a cofactor (or an assistant) for collagen production. As collagen is necessary for cell barriers, vitamin C helps maintain cellular structure.
It also has an extremely important role in both innate and adaptive immune cell formation and activity. Vitamin C plays a role in microbial killing, helping immune cells migrate to the site of infection, cell growth, cell differentiation, enhancing antibody levels, and decreasing histamine levels.
Food sources are always best, and this is especially true with vitamin C. It’s bioavailability (or ability to be absorbed and used by the body) is greatest in real foods.
Sources include: citrus fruits, berries, broccoli, peppers, tomatoes, acerola cherries, spinach, kale
Zinc
Like vitamin C, zinc is a key micronutrient that affects both the innate and adaptive immune cells. It provides structural integrity for cell membranes and acts as an antioxidant to protect against free radicals.
It’s crucial for the normal development, function, and communication of immune cells. It acts as a cofactor for many biological reactions that result in the production and activity of a wide variety of immune cells.
Sources include: meat, shellfish, whole grain cereals, oats, pumpkin seeds, dairy products, lentils
Quercetin
This time of year it’s likely that you’ll be afflicted by some heavy mucus, even if you’re lucky enough to live in a warm climate. That’s where quercetin rides in on a white horse.
Quercetin reduces the expression of the gene that handles mucus production. It has also been shown to decrease inflammation in the lungs. Pretty cool, right?
Sources include: citrus, green leafy vegetables, seeds, nuts, broccoli, olive oil, apples, onions, green tea, red grapes, red wine, berries
Vitamin D
In addition to maintaining optimal blood calcium levels, vitamin D also plays an important role in antimicrobial and antiviral functions in the body.
The best source is 10-20 minutes of exposure to direct sunlight on your skin with a UV index of 3 or more (your weather app can tell you the UV index!). When sunlight is minimal in winter months, supplements are your best friend. You may also want to consider supplementation year-round if you:
- Live in a very northern country
- Choose to cover your skin
- Spend most days indoors
- Are at risk for osteoporosis
- Are pregnant or planning pregnancy
Sources include: sunlight, high quality D3 supplements (10+mcg/day)
(Food sources tend to be inadequate to meet requirements.)
References
Brito, J. C. M., Lima, W. G., Cordeiro, L. P. B., & Cruz Nizer, W. S. (2021). Effectiveness of supplementation with quercetin‐type flavonols for treatment of viral lower respiratory tract infections: Systematic review and meta‐analysis of preclinical studies. Phytotherapy Research, 35(9). https://doi.org/10.1002/ptr.7122
Carr, A. C., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5707683/
Martens, P.-J., Gysemans, C., Verstuyf, A., & Mathieu, and C. (2020). Vitamin D’s Effect on Immune Function. Nutrients, 12(5), 1248.
https://doi.org/10.3390/nu12051248
Parasuraman, S., Anand David, A., & Arulmoli, R. (2016). Overviews of biological importance of quercetin: A bioactive flavonoid. Pharmacognosy Reviews, 10(20), 84. https://doi.org/10.4103/0973-7847.194044
Parasuraman, S., Anand David, A., & Arulmoli, R. (2016). Overviews of biological importance of quercetin: A bioactive flavonoid. Pharmacognosy Reviews, 10(20), 84. https://doi.org/10.4103/0973-7847.194044
*This guide is for educational and information use only. It is not medical advice and should not be used to diagnose or treat a health problem or disease. Please always consult your doctor regarding a medical condition.
