Concentration of CO2 in the Atmosphere

Evolution, Perception Vitamin D

Larry Plesent

Long ago our more apish ancestors had to determine which green leaves and which red berries were the ripest. They learned to quickly choose one item from a field of very similar appearing objects. This ability to differentiate underpins the way our brains work and is thus baked into the biases and methods through which we perceive, evaluate and alter the world.

Nature does her work in systems or “bundles.” Human brains tear apart that bundle and analyze its parts as unique and distinct entities. This analytic approach to understanding the world has resulted in huge, snowballing leaps in technology and in the general knowledge base.

It has also contributed to our extremely unbalanced approach to everything from energy generation, food production and house building, to allowing the proliferation of single use products and the world-wide cancer epidemic that is the inevitable result of all that lopsided thinking. It is our greatest tool and, unless we all work together nicely, has the capacity to destroy all that it creates.

This bring us to our discussion on vitamin D, a nutrient so important our skin uses sunlight to make it for us. Conventions dictate the daily covering up of skin surfaces (leaving our all-important faces exposed). We only drop the convention when taking a vacation from our “real” lives. The more “on vacation” we are, the more skin we can comfortably expose in public without risking sexual advances. If this seems bizarre to you join the club.

The consequences of too little vitamin D are visually obvious; our bones become soft, brittle, and eventually deformed. The best science we have on vitamin D relates to its relationship to calcium metabolism and bone structure. That’s why we put it into milk, a food source notoriously low in it. I must assume that babies are born naked for a reason, as mother’s milk is also low in vitamin D.

One very large and long-running study found that too much vitamin D increased the prevalence of bone fractures. If we need another example of the wisdom in moderation here it is. Vitamin D good. Too much, not so good.

This provides a sound biological basis for the darkening of human skin through tanning and evolution. If your more recent ancestors came from the north your skin is light. If they came from the equator, it is dark. Middle regions tend to be shaded in between. Simple and logical. If our collective brains would allow us to stop focusing on our minor differences, peace might actually break out in the world.

Vitamin D is so critical to human functioning, so baked into our metabolic processes, if it were discovered today, we would not call it a vitamin, but something closer to a hormone or even a building block for making a human. Vitamin D is involved in glucose metabolism and insulin uptake, thyroid and parathyroid function, hormonal balance, mood regulation, adrenal and stress response, calcium and phosphorus metabolism, reproductive health, and general immunity. We ignore it at our peril.

How much vitamin D is enough? Start with 400 IUs a day for an adult, obtained through diet. If you are older, larger, darker, carry extra fat, have trouble digesting fats, are already D-deficient, have health issues involving the processes outlined above, or live in a dark closet you will need more.

The Endocrine Society recommends levels higher than the USDA. From their perspective a large, dark skinned, 67-year-old male carrying extra fat would optimally use about 800 to 1000 IUs daily. If he lives in sunlight deficient regions part of the year, go with the higher number.

Women need a little less. Children even less, and babies need baby amounts. There are good tables available on the internet if you really want to dial it in.

Or just run around naked in the sun for a half hour every day. Clothes are overrated anyway.

Larry Plesent is the founder of Vermont Soap and is a writer and natural products formulator residing in the green hills of Vermont. Read more from Larry’s work at

To see this article in a pdf file, as it appears in print, please click HERE.

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