The Stoic Manual

The Stoic Manual

Science-based Health Tools

#18. The Silent Pandemic

Over 70% of the U.S. population has either a deficiency or insufficiency in vitamin D.

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Stoic Philosophy
Jun 18, 2025
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God Creating The Sun by Michelangelo

I’ve noticed a troubling pattern in the hundreds of patients I see every week.

Most are office workers or people who spend all day indoors. They complain about chronic back pain. They look tired and hollowed out. Their moods are low. They fall sick often. And a surprising number have blood tests showing low levels of Vitamin D3, the active form of the steroid hormone our skin synthesizes from the sun.

This isn’t a random finding. It lines up with data showing that over 70% of the U.S. population has either a deficiency or insufficiency in vitamin D. And no, it’s not just a Western problem. It’s global. Even in countries with sun exposure all year round. Why?

Because the risk factors for deficiency have embedded themselves into our modern lives. We work in buildings. Commute in vehicles instead of walking. Spend most weekends indoors and only go out at night. Our skin is often covered—by long sleeves, sunscreen, or just the default of always being in a …

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