• Emily Achey, MS, RD

Nutrient Spotlight: Vitamin D | Are You Getting Enough?

Updated: Jan 30, 2019

Vitamin D is buzzing these days for its “hard to get” attitude and widespread health benefits. Although the colder months bring fun holiday festivities, there’s a good, and unfortunate, chance Vitamin D is left out of the party. Between the layered clothing to keep warm, lack of outdoor activities, and UVB ray blocking sunscreens, this “Sunshine Vitamin” is easily neglected.

The RDA for Vitamin D is 400-800IU/ day (or 10-20mcg/day), but some experts suggest 1000-4000IU/day (or 25-100mcg/day) is necessary to maintain adequate (and optimal) levels within the blood (1). The revised nutrition label released in 2016 included Vitamin D content to be disclosed on all labeled food products due to the heightened prevalence of Vitamin D deficiency in America. Keep reading to see how you measure up.

Why should we care?

Well, here are the benefits:

Bone Health (most well known benefit)

Vitamin D is necessary to absorb Calcium from the intestines in order to build and maintain strong bones and teeth.The combination of Vitamin D and Calcium has been shown to prevent osteoporosis in older adults, build stronger bones in the young, and maintain bone integrity throughout adulthood (2).


Vitamin D has been shown to have many effects on cell function within the immune system. Deficiency in Vitamin D has been linked to greater autoimmunity and greater risk of infection (think: cold season) (3).


Seasonal Affective Disorder (SAD) and Vitamin D deficiency is a double whammy! Studies show that Vitamin D deficiency may partially cause SAD, as well as the widespread diagnosis of depression (4).

A Host Of Chronic Diseases

Long term studies have suggested adequate Vitamin D levels to prevent against Cancer, Alzheimer’s disease, Heart Disease and Diabetes (5).

Now that you know why Vitamin D is so important...

Let's make sure you’re getting enough.

Here’s a quick (yes/no) quiz to give you an idea:

🔲 Do you live in a northern latitude (above 40º)?

Even if you are enjoying the winter outdoors with bare skin, chances are the UVB rays are not strong enough to manufacture Vitamin D.

🔲 Are you nearing or greater than 70 years old?

Due to the natural aging process, the skin’s ability to produce Vitamin D with sufficient UVB rays decreases.

🔲 Do you wear broad spectrum sunscreen when you are in the sun?

This block UVB rays, which are needed to produce Vitamin D, and is the favorable choice to reduce risk of skin cancers.

🔲 Do you have a BMI in the obese range?

Vitamin D is a fat soluble vitamin and has been shown to be distributed within adipose tissue, leaving the cells that need it, deficient.

🔲 Do you have a dark skin (Hispanic or African American decent)?

Darker pigmentation significantly decreases the production of Vitamin D on the skin, when compared to lighter pigmented skin.

🔲 Do you have a genetic polymorphism?

It’s okay if you don’t know the answer to this, but know that your genetics may have an effect of you body’s ability to produce and metabolize vitamin D.

If you said YES to any of the questions above, working on increasing your Vitamin D levels is likely a good idea. Here are a 3 generalized ways to do so:

  1. Get your blood levels tested. This is a great place to start and the only surefire way to determine if you are actually deficient. Ask for the 25-hydroxy Vitamin D blood test (this is the storage form of Vitamin D in your body). And of course always consult your physician for advice.

  2. Incorporate food sources. It can be very difficult to get sufficient Vitamin D through food alone, but it can absolutely help. Check out the following sources:

Excellent sources: fatty fish (salmon, tuna, mackerel, swordfish), cod liver oil

‘Okay’ sources: fortified orange juice, fortified milk and fortified yogurt

‘Low, but still a source,’ sources: eggs (with the yolk!), cheese, fortified cereal

*Keep in mind that fortified foods are likely highly processed sources, and may contain unfavorable added ingredients.

3. Consider supplementation. Here are a couple guidelines to consider:

Choose Vitamin D3 (Cholecalciferol), and follow dosing directions on the label, or directions from your Doctor who may prescribe additional supplementation if blood levels are suboptimal.

Liquid supplements are easier for the body to digest and absorb than in pill form. There are many liquid Vitamin D3 options, just be sure to follow the storage directions on the label.

Always take with fat! The supplement directions should say something along the lines of "take daily with a meal." If it doesn't, remember this! Vitamin is fat soluble, which means it must be in the presence of fat to be absorbed. Take with a meal containing some fats, (oil, avocado, nuts, seeds, etc.) and as a bonus, throw in some calcium, too ;) (see benefit: Bone Health above).

The take away: Vitamin D serves many important roles within the human body. It is important to maintain sufficient intake of Vitamin D within the diet or through supplementation if UVB sun exposure is lacking. Striving for optimal blood levels of Vitamin D is the best way to reap the complete spectrum of benefits.

For individualized recommendations, or your free consultation with a Registered Dietitian, please contact today!


  1. Armin Zittermann, Simona Iodice, Stefan Pilz, William B Grant, Vincenzo Bagnardi, Sara Gandini; Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies, The American Journal of Clinical Nutrition, Volume 95, Issue 1, 1 January 2012, Pages 91–100, https://doi.org/10.3945/ajcn.111.014779

  2. Michael F. Holick; Vitamin D and Bone Health, The Journal of Nutrition, Volume 126, Issue suppl_4, 1 April 1996, Pages 1159S–1164S, https://doi.org/10.1093/jn/126.suppl_4.1159S

  3. Aranow C. Vitamin D and the immune system. J Investig Med. 2011;59(6):881-6.

  4. Penckofer S, Kouba J, Byrn M, Estwing Ferrans C. Vitamin D and depression: where is all the sunshine?. Issues Ment Health Nurs. 2010;31(6):385-93.

  5. Wang H, Chen W, Li D, et al. Vitamin D and Chronic Diseases. Aging Dis. 2017;8(3):346-353. Published 2017 May 2. doi:10.14336/AD.2016.1021

DISCLAIMER: This blog provides information that should not take the place of medical advice. You are encouraged to talk to your healthcare providers about your interest in, questions about, or use of dietary supplements and what may be best for your overall health.

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