8 Factoids You May Not Know About Vitamin D

  1. 20 minutes of summer sun exposure gives you 20,000 IU of vitamin D. Sunblock can block vitamin absorption, so consider applying sunblock after you get some quality time with the sun and apply it well before you burn.
  2. You can also get vitamin D from foods sources like oily fish (Salmon, Tuna, Mackerel), eggs, and mushrooms. Though dairy products advertise being Vitamin D fortified, they are most often fortified with Vitamin D2 that is less absorbed.
  3. Vitamin D is actually the only vitamin that is also a hormone. Vitamin D is actually a type of steroid hormone, so it has the ability to reduce inflammation and pain. Studies show a relationship between pain and disease progression and vitamin D status in people affected by the autoimmune disease, Rheumatoid Arthritis.
  4. It is a fat-soluble vitamin, so your body has the ability to store it unlike water-soluble vitamins like vitamin C and B that are excreted if not needed.
  5. 70% of adults and children in America and 1 billion people worldwide are vitamin D deficient. As mentioned before, 20 minutes of summer sun exposure is needed to get 20,000 IU of vitamin D.  With our busy lifestyles spent mostly indoors, it is no wonder most of us are deficient.
  6. Vitamin D plays a role in more than 200 genes in our body affecting reproduction, heart health, nerve health, immune function and more. A subset of these genes regulate cell change and growth. Vitamin D deficiency has been linked to many cancers including breast and prostate.
  7. Certain medications can increase or decrease vitamin D absorption.
    1. Increase vitamin D:
      1. Estrogen Replacement
      2. The diuretic class of Thiazide
    2. Decrease vitamin D:
      1. Antacids
      2. Calcium Channel Blockers for high blood pressure
      3. Certain weight loss products like Orlistat (Alli)
      4. Anticonvulsant medications
      5. Steroids like prednisone
  8. You can test vitamin D in the blood by asking your doctor for a 25-hydroxy Vitamin D test. Optimal levels are above 45 ng/dl.  It is best to test your levels in the fall as it follows summer sun exposure and if you are still deficient, you can boost up your stores by winter.  It is important to have this nutrient on board as it is a good immune booster.


Bartlett, S. and Haque, U. Relationships among vitamin D, disease activity, pain and disability in Rheumatoid Arthritis. Clinical and Experimental Rheumatology, Sept-Oct 2010;28(5): 745-7.

Morris, H. Vitamin D: A Hormone for All Seasons – How much is enough?  Understanding the New Pressures.  Clinical Biochem Rev, Nov 2004, 25, 21-32.

Chiang, K. and Chen, T. The Anti-Cancer Actions of Vitamin D.  Anti-Cancer Agents in Medicinal Chemistry, 2013, 13, 126-139.

Chanel Aflatoun

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