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How Low Vitamin D Season Affects Your Health

“There is no such thing as flu or cold season, there is only low vitamin D season.” -Dr. Ryan Cole, MD

Low or deficient vitamin D is more common than you might think.

Vitamin D insufficiency/deficiency is highest among people who are elderly, institutionalized, or hospitalized and the highest risk factors for infections are advanced age, obesity, and vitamin D deficiency.

Vitamin D is a fat soluble vitamin that really is considered a pre-hormone because it acts like a (steroid) hormone in your body.

It is produced when sunlight hits your skin and your liver converts it into 25-hydroxyvitamin D (25 (OH)D-aka calcidiol) which is a stable form & the best indicator of vitamin D levels in your body.

This form gets converted again in the kidneys into 1,25-dihydroxyvitamin D (1,25 (OH2)D) which the active form of vitamin D (aka calcitriol). Not a very stable form to test for in labs, but if you're really inflamed or your vitamin D levels are staying low no matter how much you supplement, I would check here.

This is why you need a healthy liver and kidneys to make vitamin D from sun exposure.  

Vitamin D also:

• Promotes immune tolerance

• Helps calm autoimmune reactions/ inflammation

• Increases activity of T-regulatory cells which helps maintain immune tolerance

• Promotes calcium absorption in your gut

• Maintains proper calcium and phosphate levels to help with bone health

• Can help improve thyroid antibody levels

• Improves insulin sensitivity

• Modulates and regulates your cellular health & growth cycle

Vitamin D has other roles in the body including reduction of inflammation, modulating processes like cell growth, neuromuscular and immune function, and glucose metabolism. Vitamin D also affects metabolism of zinc which is important for immune function!

The Recommended Dietary Allowances (RDAs) for Vitamin D established by the Food and Nutrition Board (FNB) at the Insititute of Medicine of the National Academies is:

600 IU for Adults (male and female) age 1-70 yo

800 IU for Adults (male and female) over 70 yo

Pregnant or Breastfeeding : 600 IU/ 15mcg

This is representing a daily intake that is sufficient to maintain bone health and normal calcium metabolism in healthy individuals.

If you have an autoimmune disease or chronic diseases, that’s probably not going to cut it for you. This is why it's important to get your levels checked!

Vitamin D insufficiency or deficiency is commonly associated with various autoimmune diseases like Hashimoto’s, Rheumatoid arthritis, Type 1 Diabetes, Celiac Disease, Systemic Lupus Erythematosus, and Multiple Sclerosis.

If you or anyone you know have any of these risk factors, they are more likely to develop a vitamin D deficiency.

Here are some risk factors for developing vitamin D deficiency:

  • Living in further away from the Equator (above 35th parallel) or areas with lots of atmospheric pollution (like LA)

    • The angle of the UV light is blocked by the ozone & air pollutants

  • Darker skin

    • More melanin in skin reduces production of vitamin D in skin

  • Older than 50 years old

    • Increases difficulty making vitamin D in the skin

  • Overweight or obesity

    • Obesity /weight gain —> increase fat—> can’t convert sunlight to vitamin D effectively availability of vitamin D

  • Chronic Kidney disease

    • Kidneys are important to convert vitamin D to its usable form.

  • Gut issues like inflammatory bowel disease, celiac disease, or gallbladder issues -decreases your ability to absorb fats.

  • Vitamin D is fat soluble so you need to have a healthy gut and gallbladder in order to absorb it.

  • Magnesium deficiency (one of the most common nutrient deficiencies). Magnesium is a necessary to convert vitamin D to an active form.

  • Medications: Statins, Steroids, Anti-TB, Glucocorticoids

  • Avoid sun exposure (wearing protective clothing, office jobs)

According to the NIH,

  • Vitamin D deficiency is considered anything below 30 nmol/L

  • Vitamin D insufficiency is 30-50 nmol/L

  • Vitamin D sufficiency is 50-100 nmol/L -Goal range for optimal bone and overall immune health!

This is an app to check when its the best time to get vitamin D from the sun in your area: http:/

If you or anyone you know have any of these risk factors, they are more likely to develop a vitamin D deficiency and will probably need to supplement. Supplementing is safe when done properly so check with your doctor! When picking a supplement, look for a liquid or liquid capsule form of vitamin D. Since it is fat-soluble, taking it with some fat will help it absorb better in your small intestine.

Again, if you have a vitamin D deficiency or insufficiency, then the amount of vitamin D you may need to get your levels up & then maintain your levels, could look very different from the Recommended Dietary Allowance (RDA) number.

You'll need to figure out how much you need to be on in order to raise your levels to "normal" ranges. So take the time to get your vitamin D checked. It’s easy to add to your annual labs & will be a baseline for any future labs.

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