There are three sources of Vitamin D: food, sunlight, or ultraviolet light exposure, and supplements.
Food only contributes about 10 percent of total Vitamin D requirements for most people with
an average diet. So, it's not a sufficient source of Vitamin D for many people. Which is why so many are
deficient. And sunlight is not really a viable route of exposure for most people now
because of our indoor lifestyle. You know, those who live in the bay area in the winter time you know
the solar angle is low so even if we are exposed to sun we may not produce very much Vitamin D.
So Vitamin D is one of those nutrients that many people actually probably do
benefit from supplementing with although even that is somewhat controversial.
Cod liver oil also contains Vitamin D in addition to Vitamin A.
One teaspoon contains 400 iu which is 100% of the RDA for Vitamin D. Also Vitamin A and D have
a synergistic relationship. Vitamin A protects against toxicity of Vitamin D and vice versa.
So this again is another nice nutrient synergy thing that's happening in a whole food.
Cod liver oil kills three birds with one stone it doesn't just have Vitamin
A and Vitamin D it also contains EPA and DHA which are the long chain
omega-3 fats which are anti-inflammatory and which many Americans also don't get enough of.
Sun exposure, ultraviolet light exposure is the best option if it's feasible. Full body
exposure to midday summer sun will produce about 10,000 IU Vitamin D in half the amount of time
it takes your skin to turn pink. And I put it specifically that way because
you know everyone has different skin tone so someone with darker skin will have to
spend more time in the sun to produce that amount of Vitamin D where someone
with very pale skin that could happen in as little as 10 to 15 minutes in the summer.
When the solar angle is high, or if you're living in a more, you know, equatorial region.
However both obesity and inflammation have been shown to decrease the conversion
of sunlight into Vitamin D so you could take you know 10 different people and they would
produce even with the same skin tone and they would produce different
levels of Vitamin D given a certain amount of exposure
to sunlight based on what's happening in their body. So there are a lot of factors to consider.
So D3 supplementation is often required for the reasons that I just mentioned.
The target I would suggest is between 40 to 60 nanograms per milliliter.
You see some recommendations to drive Vitamin D very high up to a hundred. I don't believe those
are justified, or warranted, and I think there's some concern about toxicity at that level.
The Institute of Medicine recommends a range of 25 to 50. I think 40 to 60 is a nice safe middle
range that is not very controversial in the scientific literature. It is important to get
your Vitamin D levels tested. I have seen many patients in the clinic who have toxic levels
of Vitamin D because they went to the doctor, again several years ago, they got tested they were really
low the doctor put them on 10,000 IU, you know a day, a very high dose and they continued to take
that dose for several years. And then they come in and they get tested and their levels 120 or 130.
Levels of Vitamin D that high have been associated with kidney stones and arterial calcification.
More deposition of calcium in the arteries which increases the risk of heart disease which is the
number one cause of death. So we're not doing any favors by you know taking very high amounts
of Vitamin D for a long period of time. And it really is important to get your levels tested.
Your doctor will do it. You can order even at home tests it's very easy to do.
So just make sure that you do that if you are going to supplement with Vitamin D.