It’s no secret how important it is to support immune function. Did you know that vitamin D plays a pivotal role in supporting immunity? Here’s how.
Immunity with Vitamin D
Researchers discovered long ago that vitamin D provides critical support to bone health but the realization that it also provides immune system support is more recent.1 How does vitamin D help your immune system? Several ways.
The immune system is made up of many cells including monocytes, macrophages, dendritic cells, and lymphocytes. We now know that these important immune system cells have vitamin D receptors and a vitamin D activating enzyme, which means these cells can produce and respond to activated vitamin D.2
Vitamin D also has important antioxidant activity which helps support the immune system by addressing oxidative stress.3
The immune system has two types of responses: innate, which is the first line of defense, and adaptive, which takes over when the innate response is done. In addition to cellular support and antioxidant activity, research shows that vitamin D can help support both innate and adaptive immunity.1
This means that immune system support requires that you get enough vitamin D either through food, sunlight, dietary supplements or a combination of the three.
Sunlight and Supplements
There are two main forms of vitamin D—D2 and D3. Vitamin D absorption is better with D3, and it is also the most easily metabolized form of vitamin D.
Research shows that only a small amount of vitamin D3 comes from the diet with most of it coming through the skin via sun exposure.4 Vitamin D synthesis through the skin only occurs when the sun is above 45 degrees, which means that it is not produced in many major populations in North America for six months of the year.5
Some foods such as dairy and orange juice are fortified with vitamin D3. Few foods are naturally high in vitamin D3 with the best sources being the flesh of fatty fish and fish liver oils.6
Low levels of vitamin D3 are common with a recent review article published in the journal Frontiers in Nutrition concluding that this is a global health concern.7 That’s why taking vitamin D3 as a dietary supplement may make sense for most people.
While the recommended amount of vitamin D3 for adults is 600 IU, the Endocrine Society states that adults may need 1,500 to 2,000 IU daily.8
For optimal immune system support, don’t forget about D3. KAL has multiple vitamin D-3 supplement options. If you like a softgel formula, D-3 25 mcg ActivGels™ are the best option with 1000 IU per softgel. If you like an option with more D-3 power, D-3 125 mcg ActivMelt® Tablets have 5000 IU per tablet and instantly dissolve in your mouth, making it easy to take on-the-go. Plus, they come in a delicious lemon-lime flavor.
- Aranow C. Vitamin D and the immune system. J Investig Med. 2011;59(6):881-886. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/?report=reader
- Ao, T, Kikuta J, Ishii M. The effects of vitamin D on immune system and inflammatory diseases. Biomolecules. 2021; 11(11). https://www.mdpi.com/2218-273X/11/11/1624
- Sepidarkish M, Farsi F, Akbari-Fakhrabadi M, et al. The effect of vitamin D supplementation on oxidative stress parameters: a systematic review and meta-analysis of clinical trials. Pharmacological Research. 2019;139:141-152. https://www.sciencedirect.com/science/article/abs/pii/S1043661818312106
- Sirbe C, Rednic S, Grama A, Pop T. An update on the effects of vitamin D on the immune system and autoimmune disease. International Journal of Molecular Sciences. 2022;23(17). https://www.mdpi.com/1422-0067/23/17/9784
- Bishop EL, Ismailova A, Dimeloe S, et al. Vitamin D and immune regulation: antibacterial, antiviral, anti-inflammatory. JBMR Plus. 2021;5(1).
- Harvard School of Public Health. Vitamin D. 2023, March. https://www.hsph.harvard.edu/nutritionsource/vitamin-d/
- Cui A, Zhang T, Xiao P, et al. Global and regional prevalence of vitamin D deficiency in population-based studies from 2000 to 2022: a pooled analysis of 7.9 million participants. Frontiers in Nutrition. 2023;10. https://www.frontiersin.org/articles/10.3389/fnut.2023.1070808/full
- National Institutes of Health Office of Dietary Supplements. Vitamin D fact sheet for health professionals. 2023;Sept 18. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/