My All-Time Favorite Vitamin by: Dr. Shaila Callaghan

Ahh…the sunshine vitamin! Vitamin D, that is. Are you getting enough?

by Dr. Shaila Callaghan
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Many Canadians are deficient in this essential vitamin, and the most recent research shows that it can be a major factor for helping to prevent some of the top chronic diseases, such as cancer and diabetes. Achieving optimal Vitamin D levels (100-150nmol/L) plays a very important role in  making sure that your body functions the way it is intended – this one vitamin interacts with over 3,000 of your genes (The Vitamin D Society). You probably knew that Vitamin D is important for your bones, but did you know that it can help to prevent many other diseases, including: tuberculosis, psoriasis, multiple sclerosis, inflammatory bowel disease, type-1 diabetes, high blood pressure, heart failure, myopathy, breast and other cancers? In fact, it is projected that the incidence of many of these diseases could be reduced by 20-50% or more by increasing blood levels of Vitamin D ( According to Michael F. Holick, Ph.D, M.D., by achieving blood levels of 125nmol/L, we can expect…


  • Rickets, reduced by 100%
  • Osteomalacia, reduced by 100%
  • Cancers, all combined, reduced by 75%
  • Breast Cancer, reduced by 50%
  • Ovarian Cancer, reduced by 25%
  • Colon Cancer, reduced by 67%
  • Non-Hodgkins, reduced by 30%
  • Kidney Cancer, reduced by 67%
  • Endometrial Cancer, reduced by 35%
  • Type 1 Diabetes, reduced by 80%
  • Type 2 Diabetes, reduced by 50%
  • Fractures, all combined, reduced by 50%
  • Falls, women reduced by 72%
  • Multiple Sclerosis, reduced by 50%
  • Heart Attack, men, reduced by 50%
  • Peripheral Vascular Disease, reduced by 80%
  • Preeclampsia reduced by 50%
  • Cesarean Section, reduced by 75%


Holick, Michael F., PhD., M.D., Boston University School of Medicine, textbook – Physiology, Molecular Biology, and Clinical Applications (2nd Ed 2010 Humana Press). Page 12.


People in colder regions get their supply of natural Vitamin D in the summer months alone, when UV-B rays are most direct. With less sun exposure (like where I live, in Toronto), darker skin, and increased sunscreen use, less Vitamin D is formed and lower blood levels of the vitamin can be expected. People who are sun-phobic, babies who are exclusively breast-fed, the elderly and those living in nursing homes are particularly at risk of a serious Vitamin D deficiency (


Be sure to get your kids levels checked, too! Japanese researchers found that Vitamin D supplementation, particularly through the winter months, may reduce the incidence of influenza in schoolchildren (


I recommend Vitamin D supplementation to all of my patients, friends and family members – from the womb to the tomb. Have your levels checked with a 25(OH)D blood test. Aim for levels of 100-150nmol/L and enjoy all the health benefits that go along with it!


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