Vitamin D is in the headlines frequently these days. Research over the last few decades has uncovered the critical role this vitamin plays in the prevention and treatment of many illnesses. From autism to depression, osteoporosis to cancer, vitamin D has created more interest in the scientific world than any vitamin in recent history.
What is vitamin D?
Vitamin D, or cholecalciferol, is a fat soluble vitamin created in the skin as a result of sun exposure. Vitamin D has many functions throughout the body and acts in a more complicated way than other vitamins. Living in northern hemispheres, wearing clothing, sunscreen and sun avoidance greatly reduce the amount of vitamin D your body produces.
Can I get vitamin D in my diet?
Because cholecalciferol is a “vitamin”, many people wrongly assume they can get adequate amounts from their diet. Small amounts of vitamin D can be found in foods such as fortified cow’s milk and cereal, wild fish and some wild game. In response to a 30 minute sun exposure, a fair skinned person can produce 20,000IU of vitamin D. That is equivalent to 200 glasses of milk (8oz) or 50 standard vitamin D supplements (400IU) (Hollis, 2005).
What diseases are caused by a vitamin D deficiency?
In the past, vitamin D deficiency diseases were thought to be limited to rickets and osteomalacia. We now know that vitamin D deficiency plays a role in preventing and possibly treating cancer, osteoporosis, autism, asthma, multiple sclerosis, influenza, inflammatory bowel disease, rheumatoid arthritis, periodontal disease, macular degeneration, depression and chronic pain (Cannell & Hollis, 2008).
How important is it for me to take vitamin D?
A recent meta-analysis (a study that reviews other studies) determined that vitamin D appears to decrease all cause mortality (Gandini, 2007). This means that vitamin D can play a role in preventing many diseases causing premature death. Specifically it was found that maintaining a certain blood level of vitamin D decrease the rate of internal cancers by 60% (Lappe et al., 2007). The most exciting news is that supplementing with vitamin D appears to be safe and relatively inexpensive.
How do I know if I am vitamin D deficient?
I recommend that most people have their vitamin D levels checked in their blood both in summer and in winter. This is something that can be done through your naturopath or your family doctor. It is important that you have your levels of 25-hydroxy vitamin D ( 25(OH)D ) checked and NOT 1,25 dihydroxy vitamin D ( 1,25(OH)2 D ). Ideal blood (serum) levels of vitamin D are a topic of hot debate. It would appear that the minimum blood level should be 30ng/mL and higher levels are arguably important in those with existing or high risk of disease (Cannell & Hollis, 2008).
How much vitamin D should I take?
This depends on many factors including weight, skin color, pharmacological drug use, disease status and age. Once blood levels are obtained, the dosage can be individualized. However, the average adult may consider 1000 to 2000 IU per day a safe dosage. Children and pregnant women can also take vitamin D. Dosages for children should be determined by a health care professional.