[BurningFrog]

> get at least 15 (and preferably 30) minutes of direct sunlight exposure each day

This time is directly proportional to how much skin you expose to the sun. If it's only face & hands you need a lot more than if you're in the swimsuit.

It would be interesting to know what clothing the 15-30 min tip assumes.

Also, sunlight through a window does nothing. You need the UV light.

[jimmaswell]

I wonder if incandescent bulbs were better for us in this one area.

[0134340]

Not a doctor or any profession of relevance but I do use tanning lights. Incandescents produce mostly visible light and very little UVA or UVB for those health concerns. Fluorescents tend to produce more UVB in comparison but still very negligible. Tanning lights generally produce the amount of UVA and UVB needed for vitamin D synthesis although you have to use with caution.

[BurningFrog]

No, they don't produce any UV light.

Even if the filament somehow does (I doubt it), it won't make it through the glass of the bulb.

[hoseja]

I don't think incandescent bulbs produce any significant UV. The temperature is too low.