Vitamin D and Immune Health

It’s the time of year when we want our immune system to be working strong to protect us from circulating illnesses like cold and flu. The human immune system is incredibly complex and vitamin D plays an important role in the proper function of the immune system. This article explores a simplified review of the immune system and how vitamin D impacts this incredible body system. We also discuss sources of vitamin D and vitamin D supplements available at Summit RX Pharmacy. Let’s dive in!

Research shows vitamin D supports both the innate and adaptive immune system, two defense pathways that work together in harmony to keep us healthy. The innate immune system is present from birth and provides the first line of non-specific defense against germs. Its components include mucus membrane barriers, cells that activate inflammation, cells that attack germs (such as white blood cells) cells that attack damaged cells (such as natural killer cells), and more. Vitamin D helps activate white blood cells such as monocytes and macrophages in the innate immune system as the body goes on offense against an illness.

The adaptive immune system employs B cells and T cells to learn and recognize invasive threats. These incredible cells work together to “remember” past infections and create antibodies for targeted defense. When activated during an immune response, B and T cells rapidly multiply their number of vitamin D receptors. When vitamin D binds to these receptors, specific genes are turned on in the nucleus and a process is started to develop and produce more and more B and T cells until the threat to health is resolved.

In autoimmune diseases, the body’s immune system inappropriately attacks different parts of the body. For example, the most common cause of hypothyroidism is Hashimoto’s thyroiditis, an autoimmune disease where the immune system attacks its own thyroid gland. Interestingly, low vitamin D levels are associated with some autoimmune diseases like multiple sclerosis, type 1 diabetes, and inflammatory bowel disease.

How do humans get vitamin D? A limited number of foods naturally contain some vitamin D (example: fish liver oil - yum!). Fortunately, in the United States, milk and fortified cereal have vitamin D added to promote healthy vitamin D levels. Still, 2013–2016 NHANES data showed that 92% of men, more than 97% of women, and 94% of people age 1 year and older ingested less than the recommended amount of 10 mcg (400 IU) vitamin D from food and beverages.

Vitamin D is also acquired by exposure to sunlight. When ultraviolet light hits our skin, the light waves activate a prodrug that eventually becomes vitamin D. Dependence on light for vitamin D synthesis poses seasonal challenges in our region. Shorter days and cold weather in fall and winter correspond to less skin exposure to sunlight and more time indoors. Unfortunately, the UVB radiation required for vitamin D activation doesn’t penetrate through glass.

To optimize your immune health this fall and winter, consider adding a vitamin D supplement to your care routine. And while you’re at it, enjoy additional vitamin D benefits such as calcium and phosphorous absorption from your food to support strong bone composition. At Summit RX Pharmacy, we carry multiple over-the-counter products with vitamin D added such as daily multivitamins for men, women, and kids as well as a Daily Immune blend. We also offer vitamin D on its own with a higher strength of 125 mcg (5,000 IU). Ask a team member about our auto ship program and receive a discount on your next purchase!

Lastly, some prescription drugs can lower your body’s level of vitamin D. Schedule a nutrient support consult with our pharmacist Katie to review potential drug-nutrient interactions with your current medications! You can schedule a consult by filling out this form.

For more detailed information on vitamin D and its role in immune health, you can review our references here.