10 Things You Need to Know About Vitamin D

Vitamin D is a vitamin that has been getting a lot of press over the past year, particularly since some research was published supporting its ability to prevent H1N1. It is an important vitamin to know about, as we live in a northern latitude without much sunlight in the winter and in a culture that has been trained to either avoid the sun completely or to religiously use sunblock.

As more and more information about vitamin D is being discovered, I thought it’d be appropriate to compile a simple list of 10 things that contained some of the most important and current facts.

1) Vitamin D deficiency is epidemic in adults of all ages with increased skin pigmentation, who always wear sun protection, and who limit their outdoor activities. Vitamin D is produced in response to sun exposure and increased pigmentation reduces production, as does sun protection products such as sunscreen. Vitamin D production is also limited in northern latitudes. Low levels of vitamin D are also often seen in children, the elderly, and women.

2) Vitamin D is protective against cancer. In fact, one study suggests that 30% of cancer deaths could be prevented with higher vitamin D levels. Some of the ways vitamin D protects against cancer is by promoting the self-destruction of mutated cells (that could go on to become cancerous cells), reducing the spread and reproduction of cancer cells, and reducing the growth of new blood vessels from pre-existing ones, which can potentially reduce growth of previously dormant tumours.

3) Adequate vitamin D levels reduce the incidence of the flu, including the seasonal flu and more virulent strains, such as H1N1. In fact, adequate vitamin D levels are also protective against colds and other respiratory infections. Additionally, vitamin D in pregnant women reduces the incidence of newborn respiratory infections.

4) People with low levels of vitamin D are 11 times more likely to suffer from depression, including seasonal affective disorder. Vitamin D receptors are located all over the body, including the brain. Researchers have actually discovered metabolic pathways for vitamin D in the hippocampus and cerebellum of the brain, which are involved in planning, processing, and in the formation of new memories. This would explain the link between low levels of vitamin D in Alzheimer’s patients and poor results on cognition tests.

5) Vitamin D deficiency has been linked to a 50% increase in the risk of severe asthma attacks.

6) Vitamin D significantly reduces your risk of cardiovascular disease. In fact, one study indicates that women with adequate vitamin D levels may decrease their risk of death from cardiovascular disease by one-third. Vitamin D acts against heart disease by increasing the body’s natural anti-inflammatory cytokines, suppressing vascular calcification, and preventing vascular smooth muscle growth.

7) Vitamin D deficiency increases the risk of pre-eclampsia, gestational diabetes, spontaneous preterm birth, and intrauterine growth restriction. This is another piece in the growing body of evidence emphasizing the importance of adequate vitamin D levels in the pregnant population.

8) Vitamin D acts both as an immune system activator and modulator, thus reducing the occurrence of autoimmune diseases such as Crohn’s, multiple sclerosis, Type I Diabetes, SLE, and Hashimoto’s Thyroiditis.

9) Sunlight is the healthiest source of vitamin D. Contrary to what has been emphasized over the past few decades, sun exposure is actually being promoted as a health benefit. It is recommended to limit exposure or avoid the sun completely during peak hours, to use sunscreen if you must be exposed to the sun at, say noon in Mexico, and to avoid a sunburn.

10) The only way to know your vitamin D status is to have your blood levels of 25 (OH) vitamin D tested. In Canada, the normal range is 80-200 nmol/L. If you fall outside of that range (as has everyone I’ve ever tested that wasn’t taking a vitamin D supplement) then supplement with vitamin D3 and aim for some sun exposure to improve your levels. Retest your blood levels to ensure you fall into a good range and are not exceeding recommended levels. The average amount of vitamin D that an adult requires to bring up their levels into the recommended range is 3000-5000 IU/day.

This list is only a sample of what the research is demonstrating about the benefits of adequate vitamin D levels. I expect there to be new research and advances in the years to come, particularly in the area of the importance of vitamin D in pregnant women. In the meantime, get your vitamin D levels tested and don’t supplement without knowing where you stand. Enjoy the sun!