Posted on: September 20, 2015 at 6:18 pm
Last updated: July 13, 2020 at 2:05 pm

There is a single vitamin that has an effect on our ability to fight disease, both from external and internal sources. This vitamin is readily available to us in our daily lives and yet almost 40% of North Americans have a deficiency which is almost never diagnosed. This vitamin deficiency has been called the hidden cause of much of our suffering from chronic preventable diseases.


That incredibly important molecule is Vitamin D.

Vitamin D Deficiency has been linked to many cancers, high blood pressure, heart disease, diabetes, depression, fibromyalgia, chronic muscle pain, osteoporosis, osteopenia (bone loss) and even to autoimmune diseases like multiple sclerosis.


Vitamin D Regulates Your Genes and Helps Prevent Cancer

Vitamin D functions in the body as more of a hormone and gene modulator (turning on and off specific important genes in our DNA). It does so by modulating cellular growth, basically limiting cancerous cell growth when levels are optimal. It also improves cell differentiation, which puts our cells into an anti-cancer state. This is why Vitamin D is such a potent inhibitor of cancer growth and why deficiency has been linked to colon, prostate, breast and ovarian cancer.

Vitamin D Helps Prevent Infections including the Flu and Colds

A study of soldiers in Finland showed that those with levels of 25-hydroxyvitaminD higher than 16ng/mL had fewer respiratory infections than those with lower levels. Another more recent study showed that school girls who supplemented with 1200 IU per day of vitamin D3 during the wintertime, showed a significantly lower level of infections with Influenza A.

Vitamin D Deficiency is linked to Weight Gain

In a 2012 study by researchers at Kaiser Permanente involving 4600 women over a 5 year period, it was noted that women with 25-hydroxyvitamin D levels lower than 30ng/mL had higher baseline weights (148.6 lbs) compared to women with higher levels (141.6 lbs), and the women with deficient vitamin D levels were also more likely to gain 5% or more of their baseline body weight over a 4.5 year period.

Why we aren’t getting enough Vitamin D

Our bodies make vitamin D when our skin is exposed to sunlight. Between 80-100% of the vitamin D that we need on a daily basis comes from the sun. Exposure to sunlight that makes our skin slightly red (called 1 minimum erythemal dose) actually produces the equivalent of 10,000 to 25,000 international units (IU) of Vitamin D in our bodies. The main problem is that most of us are not exposed to enough direct sunlight on our skin.


In some parts of the world, people that have blood levels of vitamin D between 42 and 65 ng/mL (105 and 163 nmol/L) very rarely suffer from autoimmune disease like multiple sclerosis, type 1 diabetes, inflammatory bowel disease, rheumatoid arthritis and lupus.

Signs of Vitamin D Deficiency

Common symptoms of vitamin D deficiency include:

  • Frequent infections
  • Chronic fatigue
  • Back pain and/or joint pain
  • Low mood
  • Slow wound healing
  • Loss of bone density
  • Hair loss
  • Muscle aches

How can we increase our Vitamin D Levels?

  1. Get your 25-OH Vitamin D levels Tested.

Current normal ranges are between 10-55 ng/ml but optimal ranges for optimal health are between 40-65 ng/ml. Those with darker skin tones will have lower levels of 25-OH Vitamin D. The melanin in darker skin tones, blocks ultraviolet light from being able to produce Vitamin D in our bodies.

  1. Take the correct type of Vitamin D supplement

Vitamin D3 is the active form, and many supplements and prescriptions contain Vitamin

D2 which is not biologically active.

  1. Take the correct amount of Vitamin D supplement

If you are deficient, supplementing with 2000 – 5000 IU of Vitamin D3 daily for 3 months

(under a doctor’s supervision) is a good way to increase your levels. Once they have reached the optimal range, taking a maintenance dose of 1000 – 2000 IU daily is a good idea. Those people who live in northern climates (spend more time indoors) may need to take higher doses. Please ensure you are being supervised by a doctor when started and maintaining supplementation.

  1. Eat Dietary sources of Vitamin D which include the following:
  • Fish Liver Oils (Cod Liver Oil) – 1 tbsp (15ml) contains 1360IU of Vitamin D
  • Cooked Wild Salmon – 3.5 oz contains 360 IU
  • Cooked Mackerel – 3.5 oz contains 345 IU
  • One Whole Egg – contains 20 IU
  • Porcini mushrooms – 4 oz contains 400 IU

This vitamin is critical for good health. Start aiming for optimal levels under your doctor’s supervision and watch how your health improves!

Editor’s Note: A previous version of this article incorrectly stated that approximately 80% of North Americans are estimated to have a vitamin D deficiency. This number, however, is specific to people with darker complexions. 

This informative post was written by Dr. Navaz Habib. I encourage you to go check out his website and follow him on Facebook and Twitter

Dr. Navaz Habib
Dr. Habib is a Chiropractor, Functional Medicine Practitioner and Acupuncture Provider based out of the Greater Toronto Area. He consults with patients world-wide in regards to autoimmune, brain, gut and hormone health conditions. His goal is to find the root cause of the biochemical, physiologic, genetic, environmental and lifestyle factors contributing to his patients symptoms. Virtual consultations are available world-wide and on location in Toronto.

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