Food for thought: Vitamin D

Vitamin D is my favorite vitamin. 

I know, who has a favorite vitamin? Well, I do, and it isn’t even for a scientific reason.

When I was a kid I learned an amazing fact. Our main source of Vitamin D is sunlight. When I heard that I froze, and my mind immediately raced to the obvious logical conclusion: “If Superman gets his powers from absorbing the light of Earth’s yellow sun, and we get essential vitamins from the sun, then... Oh my god we’re all Superman.”

An exaggeration to be sure, but not as far from the truth as you may think. Let’s take a minute to appreciate Vitamin D and how it makes us a little bit more like the Man of Steel.

SUPERPOWERS
To be tehnical, sunlight doesn’t actually contain Vitamin D. Our bodies convert cholesterol to 7-dehydrocholesterol (why that happens is not important to the process). What does matter, is that when we absorb UVB rays from sunlight, we turn that 7-dehydrocholesterol into Vitamin D3.  Vitamin D3 is later activated when it's hydroxylated in the liver and kidneys. 

This is so critical because without Vitamin D you can’t absorb dietary calcium. Calcium is imperative for signalling between brain cells, developing bone density, and even maintaining your teeth. 

The “official” Recommended Daily Allowance (RDA) of Vitamin D in a given day is 600IU (International Units). But recent research has shown that the average person actually needs more like 1000 IU per day. Vitamin D levels can be affected by your age and body fat percentage. Postmenopausal women and older men in particular may need more.

KRYPTONITE
As with every vitamin, mineral, chemical, and food there is an intake sweet spot. More than that and you deal with toxicity side effects. Less than that and you struggle with the results of Vitamin D deficiency. 

Toxicity
Let’s start with getting too much of a good thing. The real issue here is the resulting high amount of calcium you’re able to absorb. Side effects of Vitamin D intoxication include nausea, vomiting, loss of appetite, thirst, weakness, and high blood pressure. And in some cases sunburn.

Deficiency
I live in Seattle. If there is a town with less sunlight, I’d rather not visit. Vitamin D deficiency runs rampant around here. Without enough Vitamin D you can’t absorb as much dietary calcium, leading to loss of bone/tooth density. From actual Vitamin D deficiency you can be susceptible to loss of muscle (especially with aging), higher risk of cancers, lower immunity, higher blood pressure, higher risk of neurological disorders, and higher likelihood of developing diabetes.

POWER UP
Now that you know how awesome Vitamin D is, how much you need, and what happens if you miss the RDA sweet spot, where the heck do I get it?

Vitamin D is very difficult to get from dietary sources. There are trace amounts in fish, cod liver oil, liver, and eggs but you can’t eat enough to fill your daily need from your food.

As we mentioned before, the perfect place to get your daily dose of Vitamin D is outside. 15-30 minutes of moderate sun exposure per day should do the trick. It won’t give you heat vision, but it’ll make a noticable difference.

If you're like most working folks it can be difficult to get that kind of sun exposure. If you live in a chronically overcast city it makes it almost impossible. In these cases it can be smart to take a Vitamin D supplement.

Keep in mind that glass and sunblock don’t let any UVB through. Sunlight through a window won’t do the trick.

TO BE CONTINUED…
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On the next Food for Thought we will explore another common point of deficiency: Iron.