Vitamin D: The Sunshine Hormone

Vitamin D barely deserves the name “vitamin.” Your skin actually makes it when sunlight hits it, which makes it behave more like a hormone than a nutrient. That’s also why it’s the one so many people genuinely lack.

It does a lot. It helps you absorb calcium (no D, no strong bones), it supports your immune system, and low levels are linked to low mood. The classic deficiency signs are vague and easy to ignore: tired, achy, foggy, catching every bug going around.

Why so many people run low

Here’s the most-searched worry — am I deficient? — and the honest answer is: statistically, maybe. Roughly a billion people worldwide are short on vitamin D, and the further you live from the equator, the worse it gets.

The reason is simple geometry. In a Canadian winter — looking at you, BC — the sun sits too low for too long to make much vitamin D in your skin. Add sunscreen, indoor jobs, and darker skin tones (which need more sun to make the same amount) and you’ve got a continent quietly running on empty from October to April.

Why food won’t save you

This is the frustrating part. Very few foods carry meaningful vitamin D. Fatty fish like salmon is the best natural source; egg yolks and fortified milk chip in a little. But you’d have to eat salmon most days to hit a solid level from diet alone.

So for many northern folks, the realistic plan is: sunlight when you can get it, plus a modest daily supplement through the dark months. Vitamin D is genuinely one of the few supplements worth taking — not because pills are magic, but because winter geography is stubborn.

A word of restraint: more is not better here either. D is fat-soluble and stored, so megadoses can build up. A sensible daily amount beats a heroic one. If you want to know your number, a blood test settles it in a day.

The takeaway: vitamin D is the rare supplement most northerners genuinely benefit from — sun is best, food is weak, a modest daily dose fills the winter gap.

Next lesson: vitamin E, the antioxidant bodyguard — and why this is one where the food version quietly beats the pill.