I started looking into the role Vitamin D plays in health about seven years ago, and was amazed at the epidemiological data behind this vital hormone. I discovered some great Vitamin D researchers and resources that I still read weekly. While we have heard more about Vitamin D in recent years, the importance of maintaining a healthy 25 hydroxy D blood level is still downplayed to a large degree.
This is due partly to the fact that 90% of what we know about Vitamin D has been discovered in the last 15 or so years. Another contributor being that it is a cheap supplement, which is also available for free (from the sun) for a large portion of the year; depending which side of the globe you call home. Ultimately no money, no noise :/
Before we get into the benefits I'll make a quick note about a study, a meta-analysis in fact, that was done in recent years. This study was widely reported in the media as 'proof' that Vitamin D does not play as much of an important role in our health, as now believed by those in the Vitamin D research field. The issue with this is that the study was greatly flawed. Among many things the researchers completing the meta-analysis worked on the premise that ergocalciferol (Vitamin D2) and cholecalciferol (Vitamin D3) are metabolically identical in the human body. This is incorrect and is a widely known fact. If you remove the D2 studies from the meta-analysis you get a result highly in favour of Vitamin D. Jon Barron wrote a great piece on this called 'Vitamin D Nonsense', if you care to know more. It's also a good reference to have should anyone raise it at a dinner party.
Now onto the benefits.. Vitamin D levels in the optimal range have been shown to prevent at least 16 different types of cancer, including skin cancer. It does this by slowing down the spread and generation of cancer cells; preventing the formation of new blood vessels from those already present (this process prevents benign tumours turning malignant), and assisting in the self destruction of mutated cells. On top of this Vitamin D also lowers the risk of a host of degenerative diseases; type 2 diabetes, alzheimers and chronic inflammation. It also helps to fight infection, keeping your levels optimal will greatly reduce your chance of getting the seasonal flu, and reduce the severity if caught.
The best way to get your Vitamin D is from the sun. Depending on your complexion, 10-20 minutes of exposure between 10am-2pm will produce the maximum amount of Vitamin D possible during the summer months. 10-20 minutes at this time will produce around 25,000IUs of Vitamin D3. You cannot overdose on Vitamin D from sun exposure as your body has a built in mechanism to hault production once a certain level has been reached. If you are darker you may need longer. Always ensure you never burn as this puts you at risk for basel cell carcinoma and squamous cell carcinoma. If you are sensitive to the sun start with a few minutes during this time and work your way up over a period of weeks, ensuring that you don't over expose. Once you have your exposure cover up or use a natural sunscreen. Exposure outside these times is not advised as the axis of the earth tilts, blocking out the UVB rays and exposing you to more UVA. UVB is responsible for the photosynthesis of Vitamin D on the skin and is the shorter wave. UVA is the longer wave that penetrates the skin deeper and offers no benefit to Vitamin D production.
Another important factor to remember is that when the sunlight hits your skin, the UVB light starts a metabolisation of the cholesterol in your skin which in turn converts into D3. If you wash with soap too soon after sun exposure you will interrupt this process and not receive the full benefit of your exposure. If you can, only wash under your under arms, groin and feet after sun exposure for 24-48 hours.
During the winter months supplementation is possible to keep your blood levels stable. Currently the recommendations of the government and researchers are out of alignment. Supplementing with 1000-2000IUs on days you don't get sun exposure will keep your blood levels in an optimal range. However, if you are going to supplement please get your 25 hydroxy D levels checked before starting, and then after 3 months. You can adjust dosage from there. Always get a blood test every 6 months until you are confident your levels are in the correct range with your dosage. If you are going to supplement you also need to take a Vitamin K2 supplement as this allows calcium to go to the right places and is vital to preventing calcification in your body. As a general rule 1/10th the K2 for every 1000IU of D3.
This is a favourite topic of mine and there's a lot more to share, but we'll cover that on the website soon.