Vitamin D and Immunity: The immune system is a complex system that defends the body from infection. As we embark on the shortest (and coldest) days of the year, the UV is at its lowest point, which means the least vitamin D is available to synthesize in our skin (if any at all). Understanding the link between vitamin D and immune health could very well mean that a quality vitamin D supplement would be the ultimate secret weapon to get through cold and flu season without a sniffle in sight!

This article has been medically reviewed by Dr. Charles Penick, MD

Your Immune System and Health

If you want to protect your body against pathogenic bacteria, fungi, and viruses, it’s time to give a little attention to the immune system. The immune system is made of cells, tissues, and organs that protect your body from infections. The complex network includes white blood cells, organs, and tissues of the lymphatic system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels, and bone marrow.¹

Signs that your immune system is struggling include:²

• You have high-stress levels;
• You are often or chronically tired;
• Your wounds (cuts, scrapes, bruises) heal slowly;
• You often have underlying cold symptoms (sore throat, sniffles, block sinus);
• You have chronic digestive issues.

Although there are many moving parts to the immune system, a nutrient is being used across the globe to improve a variety of immune-related illnesses and diseases. You guessed it: vitamin D.

Vitamin D and Immunity: The Immune System

Vitamin D acts like a hormone in the body. It is responsible for various biological effects, including increasing the bioavailability of minerals like calcium, magnesium, and phosphate. Vitamin D impacts health markers like mood, weight, energy, and immune health.^4-7

Vitamin D directly interacts with immune cells and plays a crucial role in activating their defenses. It enhances immune cells’ functions like T cells and macrophages, which protect your body against pathogens.⁸ Vitamin D also has anti-inflammatory and immunoregulatory properties and enhances immune cells.⁹

The interaction that vitamin D has with the immune system is well studied. It is being used as a primary or secondary treatment for many infections and illnesses, including tuberculosis, psoriasis, eczema, Crohn’s disease, chest infections, wound infections, influenza, urinary tract infections, eye infections, and wound healing benefit highly from supplementation of vitamin D.¹⁰

Vitamin D deficiency has been linked to many immune-related illnesses, including an increased risk of respiratory diseases like asthma and tuberculosis and bacterial and viral respiratory illnesses.^11-14 This is partly due to the decreased lung function resulting from vitamin D deficiency.¹⁵

Knowing this, it’s not surprising that cold and flu season rears its head in the year’s colder months. With less access to natural vitamin D synthesized from the hot UV rays sun, our defenses are naturally down, and pathogens have an easier time taking up residency in our bodies.

Vitamin D and Immunity: How Much Vitamin D Do We Need?

How much vitamin D we need is a million-dollar question. Recommendations vary wildly, from the very low government-recommended daily intake (RDI) of 600 international units (IUs) to the mega-doses some doctors give out 50,000 IUs per day.^16,17

Many studies hover around the 4,000 IUs per day mark to dramatically reduce the likelihood of developing upper respiratory tract infections.¹⁸

Although the sun is a primary (and free) source of vitamin D, the many factors limiting its results suggest that a vitamin D supplement may be appropriate and beneficial to most people. The impacts of vitamin D deficiency are common and severe, but getting too much vitamin D is extremely rare.¹⁹

Sources of Vitamin D

The Sun

Getting vitamin D from the sun is the most obvious (and free!) way to get vitamin D. We synthesize vitamin D from a chemical reaction in the lower layers of the skin when exposed to UVB rays. [20] UVB rays are available during the peak hours of the day when UVB rays are available for that region.

Regions closer to the equator will have UVB available year-round, but the more dramatic the seasons, the less UVB will be available during the autumn, winter, and spring. The colder your winters, the less likely you have UVB rays available for more extended periods of the year.

Getting vitamin D from the sun requires exposing bare skin (with no sunscreen) to the sun during the ‘UVB window.’ Doing so requires a certain degree of sun safety awareness, knowing that every person has a different capacity to withstand the sun. You want to avoid burning the skin at all costs, which can damage your DNA.²¹

Food

Foods that contain vitamin D include:²²

• Oily fish (like salmon, sardines, and mackerel),
• Red meat
• Liver
• Egg yolks

The animal product’s quality will determine how much vitamin D is available; notably, you want to ensure your animal products are either pasture-raised or wild. The more time the animal spends outdoors consuming a natural (wild or organic) diet, the healthier, more nutrient-dense it will be.

Although some foods are ‘fortified’ with vitamin D, such as milk and cereals, it is better to avoid them. Fortified foods rarely contain high-quality vitamins; they are usually synthetic and do not have high potency or absorbency.

Instead of opting for vitamin D-fortified foods, it is best to stick with a high-quality supplement that you can trust.

Vitamin D and Immunity: Supplements

Supplementation is a great way to ensure your body gets enough vitamin D year-round. Some of the things to look out for to maximize your benefits when taking a vitamin D supplement include: [23]

• A vitamin D supplement that combines vitamin D2 with vitamin K2. The combination has enhanced the benefits and bioavailability of both nutrients.
• Vitamin K2 should be “MK-7”, a highly bioavailable type of K2.
• Vitamin D should be naturally derived, which is more absorbable than synthetic.
• The combination should be in an organic oil base (like olive oil) to promote bioavailability.

Quality matters. Since the supplement industry is notoriously unregulated, make sure to invest in a high-quality supplement. By doing so, you can avoid many of the dangers that can occur with low-quality supplements.

Vitamin D and Immunity: Should I Supplement Vitamin D?

Vitamin D deficiency is estimated to affect over a billion people worldwide.²⁴ In America alone, 41.6% of adults are considered deficient.²⁵ Such statistics are based on the bare minimum recommendation, not the numbers for optimal health– suggesting that most people would benefit from supplementing vitamin D for optimal well-being.

Many groups are more susceptible to vitamin D deficiency, including:

• Living far from the equator (areas with “winter” season)
• Working indoors or are generally indoors
• People who tend to cover up when outdoors
• People in an institution (like a care home)
• People who are overweight or obese
• People who have darker-pigmented skin

Most of these groups’ susceptibility to vitamin D deficiency is rooted in access to or the ability to synthesize vitamin D from the sun. People who spend more time indoors (especially during peak UV hours) aren’t likely to get enough vitamin D from the sun alone.

Although some people spend more time outside, they often cover up with clothing, shade, hats, or sunscreen. All these prevent the vitamin D produced via direct contact with bare skin.

For those who regularly expose bare skin to the sun (daily), a few factors can still impede high vitamin D levels. People with darker skin have more melanin, enabling them to spend more time in the sun without burning. However, they also synthesize less vitamin D. People living in regions of the world further away from the equator also face periods of the year where there is less or no UVB required to synthesize vitamin D.

Vitamin D and Immunity: Summary

Vitamin D plays a foundational role in generating immune health. We synthesize vitamin D from the sun when UVB rays are available and can also consume it orally via vitamin D-rich foods or supplements. The daily recommended intake for vitamin D varies wildly. Since the impact of vitamin D deficiency is well-documented, and it’s rare to have too much vitamin D: a supplement may be a good idea. This is especially true for groups more susceptible to deficiencies, like people who live further from the equator, spend more time indoors, or have darker skin. A high-quality supplement should have a D3 + K2 combination derived from a natural source and diluted in an organic oil base.

Vitamin D is crucial to the strength and health of your immune system. Unfortunately, 42% or more of the U.S. population is deficient in vitamin D, with perimenopausal women, people over 65, and those with poor nutrition habits topping the charts at even higher levels of deficiency. That makes a high-quality vitamin D supplement a MUST… but that’s not where your immune needs end…

Cyto D + K2

If you live in the Northern Hemisphere, you’re still in store for some of the year’s coldest days. And that means braving a long and lingering cold and flu season. Cold air actually allows viruses to survive longer. And fewer sunny days and a lower UV index mean we’re not getting as much natural vitamin D from the sun —a huge problem for your immune system.

But you don’t have to fear the cold. Or cold and flu season. Instead, arm yourself with the right nutrients to help strengthen your immunity and learn exactly what weakens your system…

CytoD+K2, is 2X the potency of normal vitamin D and contains the ideal ratio of vitamin D to vitamin K2 for optimal absorption. With just a dropper full per day, you can strengthen immunity, restore sleep, increase energy, improve skin health, and SO much more.

>> And for a limited time, you can save a whopping 59% on up to 6 BOTTLES.

Take advantage of the discount to stock up for yourself and those you love most!

Medical Disclaimer: This article is based on the opinions of The Cell Health team. The information on this website is not intended to replace a one-on-one relationship with a qualified healthcare professional and is not intended as medical advice. It is intended to share knowledge and information from the research and experience of the Cell Health team. This article has been medically reviewed by Dr. Charles Penick, MD, for the accuracy of the information provided. Still, we encourage you to make your own healthcare decisions based on your research and in partnership with a qualified healthcare professional.

References

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