The amount of disinformation commonly expressed about vitamin D is quite amazing.

Bogus claims:

1. Spend a couple of minutes outside and you will be OK.

2. It is absorbed through the eyes.

3. Deficiencies are rare.

When in fact:

1. Does not apply at any time when your body is covered up mostly. Wear trousers and a T-shirt and you've cut yourself off severely already. Add weather with less sun, sunscreen, and/or more clothes and you've cut yourself off almost entirely unless you are outside for very long periods of time.

2. Fuck no.

3. They are extremely common even in sunny places. In the developed world a majority of people are.

You'd think sunny places would fare better - however after moving to Key West from Montreal I discovered people here spent a lot of effort avoiding the sun (skin cancer is big down here).

As someone with fair skin, I’d be harming myself if I tried to get vitamin D from the sun. And very badly.

If you wear clothes and/or aren't near the equator it's not gonna make a big enough of a difference. Also you're gonna have to balance that with negative sun exposure. Salmon is probably a top vitamin d source, but supplements are probably the cheapest way to pack it in.

What if i don't wear clothes and is at the equator

That drastically increases your odds of skin cancer. If you want to reduce your risk of dying overall, stay covered up and take supplements.

Melanoma correlation with sun exposure is tricky; regular (non burning) exposure tends to correlate with lower risk (eg in outdoor workers). Non-melanoma skin cancers are usually curable. It's plausible to argue the benefits of regular non burning sun exposure overweight the risks.

This does not work if you have dark skin and do not live in the tropics.