Why You Need To Take Vitamin D Year-Round
First it needs to be acknowledged that vitamin D is the single most important nutrient that the vast majority of us need to supplement with, on a regular basis. “Vitamin D has direct effects on the epigenome and the expression of more than 1000 genes.” (Source)
In fact, in 2008, when vitamin D research was starting to be taken seriously, Dr.Cedric Garland, a professor of preventive medicine at the University of California, San Diego, said “I think vitamin D is introducing a golden age in medicine”. (Source)
Aside from the big three killers of modern man (cancer, diabetes, and heart disease), which are indisputably linked to vitamin D deficiency, virtually every other medical condition that I have come across has, in one way or another, a link to vitamin D deficiency. In order to prove this to yourself, simply go to the PubMed website (a free database of all the scientific research from around the world) and type in a disease or medical ailment along with the words “vitamin D”. The odds are extremely high that you will find there is a link between the two.
Vitamin D from Sunlight
Now, given that, many people still have the idea that if they spend a lot of time out in the sun, during the summer at least here in the northern hemisphere, they will acquire sufficient vitamin D for their body’s needs. (However, remember there are only 4 months of the year in Canada when the sun is strong enough to produce vitamin D in our bodies.)
And there is a bit of truth to that, but also more to the picture.
If you have at least 50% of your body exposed, and spend at least 20 to 30 minutes in the midday sun daily (minimum three times a week), you will produce a good amount of vitamin D. If you are unbathed. If you shower in the morning with hot water and soap you wash the sebum (natural oils) off your skin and the sunlight has nothing to work with. (Going into the ocean or a lake would not matter as cold water in the absence of soap will not remove sebum from your skin.)
Natural vitamin D supplements are made by exposing lanolin from sheep’s wool to ultraviolet light. And this is how the process works in the human body. Our natural sebum is like lanolin, a cholesterol-bearing oil, and vitamin D is made from the reaction of ultraviolet light on that form of oil. Thus, if you were to moisturize with any other oil (other than lard or tallow) after the shower, you still would not produce any vitamin D.
So let’s say you sunbathe correctly, half naked and dirty, still, that is not good enough. You will have produced sufficient vitamin D for your needs during the summer, but what about when the sun turns away from us?
Vitamin D in the Winter
During the summer the principle is that you produce and store extra vitamin D to help get you through the winter. This extra D is stored in your liver and fatty tissues waiting to be activated when the body requires it.
And the body determines if you need vitamin D via the kidneys monitoring the blood for sodium and potassium levels. Why? Because in the summer foods are high in potassium (especially fruits and certain vegetables) and in the winter our foods are higher in sodium (more consumption of meat and foods lower in potassium). So, if you had a natural diet of foods that grow where you live, your body would react to this by activating the vitamin D that you built-up during the summer months.
However, now that we are eating tropical fruits (especially bananas and oranges) year round, the body is fooled by the ensuing high potassium levels these foods provide, into assuming it is still summer weather, and it doesn’t bother to activate your vitamin D stores.
The basic idea behind requiring high levels of vitamin D year round is that all the genes dependent on vitamin D were established during our early phase of evolution, when we still resided in Africa. Thus, when human prototypes migrated northward, their need for a high intake of vitamin D was already established. In those days our Northern ancestors would have acquired some D from eating the organs of animals and fish to complement what they might have received from sunlight (generally being half naked and dirty in summer months).
Vitamin A
One other thing, concerning vitamin A. A young man I know works outdoors and was feeling burned out by what he felt was too much exposure to sunshine. After reading in one of my newsletters my thesis that vitamin A requires extra vitamin D to be properly absorbed, and that perhaps the reverse also holds true (that vitamin D at high levels may deplete the body of vitamin A stores,) he decided to start taking extra vitamin A, and found a distinct improvement in his energy levels.
Remember that we traditionally ate liver as a source of both vitamins A and D, and very few people in the West consume animal or fish livers anymore.
Conclusion
If you are taking a vitamin D supplement in the non-summer months, feel free to eat all the tropical fruit you want, as that base has been covered.
Those choosing to use high levels of vitamin D therapeutically should do so with the advice of a medical professional, and should test their blood levels of vitamin D regularly to ensure they aren’t overdosing on vitamin D (causing hypercalcemia, where excess vitamin D mobilizes too much calcium into the bloodstream). When taking high amounts (5,000 IU or more daily) also be sure to take some magnesium and vitamin A which are both co-factors for the absorption of vitamin D. (This is why some people who start taking high doses will get leg cramps: they were already borderline deficient in magnesium and what little they had was used up for the absorption of the extra vitamin D.)