Vitamin D is most known for its ability to support bone health.
But did you know that vitamin D is also critical to the health of your immune system?
The reality is that most tissue in the body has receptors for vitamin D. This means that many areas of the body welcome vitamin D—not just the bones.
Because of this, studies have found that levels of vitamin D play an important role in the development of:
- More than a dozen cancers, including colon, breast, prostate, and pancreatic cancer
- Autoimmune disease, like rheumatoid arthritis, multiple sclerosis, and Crohn’s disease
- Type 1 and 2 diabetes
- Cardiovascular disease
- Infectious disease
Unfortunately, the story gets worse.
It has been estimated that up to 100% of elderly men and women are vitamin D deficient. And anywhere from 42% - 50% of adults and teenagers are not getting the amount of vitamin D that they need.
Even pregnant women taking a prenatal vitamin are at risk for vitamin D deficiency.
Vitamin D is called the “sunshine vitamin” because when our skin is exposed to sunlight, it makes vitamin D.
According to researchers, the best time to get vitamin D from the sun is from 10 am – 3 pm during the spring, summer, and fall seasons. When the skin is slightly pink after exposure to the sun, you can bet that you’re getting up to 25,000 IU of vitamin D.
We can also get vitamin D from fatty fish, like salmon, mackerel, herring, and sardines.
Cereals, milks, and orange juice are fortified with vitamin D2. The vitamin D that we make in our skin and that we find naturally in foods (like fatty fish) is called vitamin D3.
One of the best sources of vitamin D3 is cod liver oil.
This is because cod liver oil contains vitamin D3, vitamin A, and omega 3 fats—all of which work together to support the immune system. Indeed, researchers have found that vitamin D, vitamin A, and omega 3 fats all play an important role in protecting against respiratory infection.
Healthy adult men and women should shoot for 600 IU per day. Growing children require more—up to 1000 IU.
1 teaspoon of cod liver oil contains anywhere from 600 – 1000 IU.
3.5 ounces of wild salmon contains 600 – 1000 IU, whereas the same amount of farmed salmon only offers 100 – 250 IU.
SOURCES:
Holick, M. F., Binkley, N. C., Bischoff-Ferrari, H. A., Gordon, C. M., Hanley, D. A., Heaney, R. P., ... & Weaver, C. M. (2011). Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology & Metabolism, 96(7), 1911-1930.
Mata-Granados, J. M., Cuenca-Acevedo, J. R., de Castro, M. L., Holick, M. F., & Quesada-Gómez, J. M. (2013). Vitamin D insufficiency together with high serum levels of vitamin A increases the risk for osteoporosis in postmenopausal women. Archives of osteoporosis, 8(1-2), 1-8.
Lentjes, M. A., Mulligan, A. A., Welch, A. A., Bhaniani, A., Luben, R. N., & Khaw, K. T. (2014). Contribution of cod liver oil‐related nutrients (vitamins A, D, E and eicosapentaenoic acid and docosahexaenoic acid) to daily nutrient intake and their associations with plasma concentrations in the EPIC‐Norfolk cohort. Journal of Human Nutrition and Dietetics.
Linday, L. A., Umhau, J. C., Shindledecker, R. D., Dolitsky, J. N., & Holick, M. F. (2010). Cod liver oil, the ratio of vitamins A and D, frequent respiratory tract infections, and vitamin D deficiency in young children in the United States. Annals of Otology, Rhinology and Laryngology, 119(1), 64-70.