Details on Vitamin D
It seems that every few years a vitamin becomes famous. Vitamin D has been enjoying the spotlight for a few years now as the “it” vitamin. Medical doctors, who seldom get as excited about vitamins as Naturopathic doctors do, are also testing and prescribing Vitamin D with fervor. Here are the most common questions I get on this crucial and often-deficient vitamin.
So the SUN gives us vitamin D! How does that happen and what does that mean for people in rainy climates?
Well, actually the sun’s UVB light triggers a reaction in our exposed skin to form Vitamin D. Living in Portland, I experience our little secret that the Great Northwest is greatly covered in clouds for half of the year. What this means for us and for other folks that miss out on ample sun exposure is that we have chronically low Vitamin D levels and really need to get those levels up! Studies have shown that people ’round the world are significantly deficient as they get farther from the equator. Almost every Portland patient I test for Vitamin D scores lower than the ideal set by The Vitamin D Council, the authority on vitamin D research.
What is Vitamin D and why is it important for us to have enough?
Vitamin D is actually a steroid hormone that is essential for life. It’s required for proper functioning of the endocrine, immune, and nervous system, as well as bone formation and serotonin (the happy hormone) production. Before it became popular, doctors only prescribed supplemental Vitamin D to prevent rickets and osteoporosis. Now we see Vitamin D being associated with almost every symptom and disease, including diabetes, heart disease, cancer, and muscle pain. Many patients report something like, “Ever since starting Vitamin D, I get one cold a year instead of five” or, “My winter-time depression was terrible until I started on that liquid sunshine you gave me.” The research on Vitamin D is abundant; if you're not getting enough sun, start getting your D elsewhere.
Does sunscreen affect vitamin D production?
Well, YES IT DOES, I’m glad you asked. It’s a seldom known fact that putting sunscreen on to block UV rays will block vitamin D production, as well. This is a tricky one since, obviously, we want to protect ourselves and especially our delicate-skinned children from harmful sun exposure. The most important thing is to get some good healthy sun on our bodies without over doing it. Depending on the time of year and shade of skin, you will need to watch for signs of redness and be careful. Ten to 20 minutes of sun exposure is safe on most skin (maybe not the fairest of babies or close to the equator). Let that sun reach as much bare skin as possible (yes, this is an endorsement to lay out naked in your back yard).
What about showering after sun exposure- does that really reduce Vitamin D absorption?
The vitamin D3 that is formed on the surface of your skin does not immediately penetrate into your blood and actually needs some time to be absorbed. The jury is still out on this however, evidence shows that it takes up to 2 days to get all of that D into the blood stream. Using soap, which cleans the oily layer off the skin, will actually reduce what you absorb! So now what? The recommendation touted by Joseph Mercola and other researchers is to avoid scrubbing sun-exposed areas with soap for two days (but please still clean the arm pits and other parts that need it!).
How can I get vitamin D tested and what range is healthy?
You can ask your doctor to asses your Vitamin D level with a simple blood test. Ask for a 25-hydroxyvitamin D, or 25(OH)D, test. You can also purchase a test to do at home from ZRT laboratory. Make sure to ask for your results, since many doctors will say your numbers are “just fine” while referring to an outdated healthy range. There is much controversy over the ideal range, actually. The vitamin D council says the number should be over 40ng/mL, Joseph Mercola says around 50ng/ml. Most Portlanders we test are showing up in the teens and 20s.
What are good food sources for Vitamin D and can I just eat my way to sufficient D?
I am a huge proponent of eating your nutrients instead of getting them from a bottle. This is one area where I feel like the food sources just aren’t going to cut it. It’s worthwhile eating the foods that are rich in D because they also have lots of other good stuff for you. The highest sources come from cold water ocean fish such as salmon, sardines, mackerel, and herring (My kids love pickled herring! They are pretty strange kids but maybe your kid is stranger than you think; try it!). The fish skin and fatty layer under the skin has most of the goods. Egg yolks are a pretty good source, as well. You can also try some blue green algae (spirulina, chlorella) and cod liver oil to get your levels up.
Ok, I am convinced I need to supplement with D. How do I do this and what dose is toxic?
There are two forms of Vitamin D: D2 and D3. Vitamin D3 is the real deal, while D2 is an impostor.
Pharmaceutical D is completely out of the question.
I like the oil-based D supplements extracted from fish (or you can just take a swig of plain ‘ol cod liver oil). Carlsons D drops are reliable. The appropriate dose needs to be determined by your physician based on your individual levels. There is a lot of controversy over ideal doses and toxic upper limits. I side with the Vitamin D council, which likes to go big with D. Here are it’s recommendations:
Healthy children under the age of 1 years – 1,000 IU.
Healthy children over the age of 1 years – 1,000 IU per every 25 lbs of body weight.
Healthy adults and adolescents – at least 5,000 IU.
Pregnant and lactating mothers – at least 6,000 IU.
As far as toxic doses, it’s actually fairly difficult to become toxic using D3 unless you really overdo it. The US Government still recommends an upper limit at 4,000 IU per day. However the D council states “Experts agree the Upper Limit for vitamin D should be raised to 10,000 IU per day”.
One thing everyone can agree on is that you can’t absorb too much D from sun exposure because your body regulates it effectively. So there you have it: one more vote to run around your back yard naked. (That is what they are saying, right?)
Sources:
Vitamin D Council (www.vitamindcouncil.org)
Interview with William B. Grant, Ph.D (http://articles.mercola.com/sites/articles/archive/2004/04/03/vitamin-d-grant.aspx)
