维生素D是一种激素，它在1922年被错误归档在错误的字母下，而这个归档错误从那时起就一直影响着你的健康建议。

维生素是人体无法自行制造的东西。维生素D由你自己制造，在你的皮肤中，大约二十分钟的夏日阳光就够了。

维生素来自食物。维生素D来自胆固醇，这是人体用来构建睾酮、雌激素和皮质醇的相同原料。

维生素一到就直接使用。维生素D先去肝脏，然后去肾脏，从另一端出来时有了新名字——骨化三醇，以及一份新工作。

维生素帮助一种酶完成任务。骨化三醇走进细胞核，坐在受体上，开关基因，这正是雌激素所做的。

维生素有一个任务。骨化三醇在你拥有的几乎每个组织中都有受体，并掌控着你基因组中约3%。

维生素几天内就会耗尽。维生素D储存在你的脂肪中数月，就像身体储存一种它预期在冬天需要的激素那样。

维生素可以从瓶子里过量服用。维生素D无法从阳光中过量，因为皮肤会破坏多余部分，这是一种恒温器，而维生素没有恒温器。

它之所以得名，是因为1922年它从鳕鱼肝油中分离出来并治愈了佝偻病，而佝偻病是由列表上的第四种营养素治愈的，所以它得了第四个字母。

十年后，化学家们证明它是类固醇。没人回去更改标签。

睾酮从未被称作维生素T。

所以现在，一种激素缺乏症用维生素药丸来治疗，这种药丸是用羊脂制成的，而激素实际产生的地方却被卖给你作为一种带有防晒系数的危害。

一个世纪以来，我们一直在告诉人们远离他们自己的内分泌系统。

Vitamin D is a hormone that was filed under the wrong letter in 1922, and the filing error has run your health advice ever since.

A vitamin is something your body cannot make. Vitamin D you make yourself, in your skin, in about twenty minutes of summer sun.

A vitamin comes from food. Vitamin D comes from cholesterol, the same raw material your body uses to build testosterone, oestrogen and cortisol.

A vitamin is used as it arrives. Vitamin D goes to the liver, then to the kidney, and comes out the far end with a new name, calcitriol, and a new job.

A vitamin helps an enzyme along. Calcitriol walks into the nucleus of a cell, sits on a receptor and switches genes on and off, which is exactly what oestrogen does.

A vitamin has a task. Calcitriol has a receptor in nearly every tissue you own and a hand on about 3% of your genome.

A vitamin runs out in days. Vitamin D is banked in your fat for months, the way a body stores a hormone it expects to need in winter.

A vitamin can be overdosed from a bottle. Vitamin D cannot be overdosed from the sun, because the skin destroys the surplus, which is a thermostat and vitamins do not have thermostats.

It got the name because in 1922 it came out of cod liver oil and cured rickets, and rickets was being cured by the fourth nutrient on the list, so it got the fourth letter.

Ten years later chemists showed it was a steroid. Nobody went back and changed the label.

Testosterone was never called vitamin T.

So a hormone deficiency now gets treated with a vitamin pill, made from sheep grease, and the place the hormone is actually made is sold to you as a hazard with a factor number on it.

A hundred years of telling people to stay out of their own endocrine system. @SamaHoole