If any specific wavelengths matter, LEDs will either have to produce all of those or there's no alternative to an incandescent light. But I suspect the human genome mostly developed absent any artificial light, including fire, so it's probably healthiest to get out during the day and sleep at night. It's not the most productive, especially where nights are long but that's kind of what we are built for. 

 No doubt getting out in real sunlight is best, we are in full agreement on that