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  • Writer's pictureMAND

A Ray of Sunshine

By Dr. Mari Sawai, ND

“Vitamin D plays a role in activating over 900 genes that play a role in fighting/preventing cancer, inflammation, and cognitive issues (Alzheimer’s and Dementia)”

– Dr. Pearlmutter, MD

Over the last few years, Vitamin D has been getting a lot of press, and for good reason. Though we have known for many years that healthy Vitamin D levels help us build strong bones by increasing the absorption of calcium and phosphorus, we now understand that the role of Vitamin D extends beyond the skeletal system. New research has shown that proper levels of Vitamin D can improve immune function and decrease susceptibility to autoimmune conditions such as diabetes mellitus, multiple sclerosis, irritable bowel syndrome, rheumatoid arthritis, and systemic lupus erythematosus. Vitamin D has been shown to improve mood (especially in seasonal affective disorder), decrease inflammation, and help keep blood sugar levels under control. Recently Vitamin D receptors have even been found in the brain stem and deficiency in Vitamin D has been linked to sleep issues like sleep apnea and insomnia. Vitamin D supplementation has been shown to modulate the innate and adaptive immune response; regular Vitamin D supplementation of 1,200IU a day was shown in one Japanese study to decrease influenza A incidence by 40% in school children over a 4 month season.

For the body to convert cholesterol into Vitamin D, 50% - 70% of your skin must be exposed to ultraviolet light (sunlight). Other factors impacting Vitamin D status include season, use of sunblock, and skin pigmentation; if you have a dark skin tone, you are more prone to having a Vitamin D deficiency. Due to the climate and the fact that we are bundled up for a good portion of the year, many people are at risk of D deficiency. If you have been living in the beautiful state for most of your life, you may want to consider adding Vitamin D to your regimen. Especially in the winter months, when Vitamin D levels tend to drop naturally.

So, exactly how much Vitamin D should you be taking? And what is the normal Vitamin D level? First of all, if you are someone with weak immune function (you get sick often or easily), autoimmune disease, fibromyalgia, osteoporosis, or diabetes, it is recommended you have your vitamin D levels checked out by your doctor. It is a simple blood, which your PCP can easily order for you. "Normal" lab reference ranges are pretty broad, at 30 - 100ng/mL. Naturopaths generally look for "functional level," on labs, meaning they aim to target optimal levels, not just within "normal for national average." A functional or optimal level of Vitamin D would be between 50-70ng/mL on labs.

An effective daily dose of Vitamin D for immune health would be between 2,000 to 5,000 IU Vitamin D3 a day. 2,000IU daily is suitable for children and dosing closer to 5,000IU a day is recommended for an average adult. Dosing with dinner is recommended as Vitamin D is a fat soluble vitamin and therefore will absorb better when taken with a fat. Evening is the preferred time to dose Vitamin D as it is actually a hormone (not a vitamin), and hormones will be better absorbed at night.


  1. Aranow C. Vitamin D and the Immune System. Journal of investigative medicine : the official publication of the American Federation for Clinical Research. 2011;59(6):881-886. doi:10.231/JIM.0b013e31821b8755.

  2. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 91:1255-60. Epub 2010 Mar 10.


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