To the people laughing at me sunbathing practically naked in the park- my health is worth more than your opinions. 

Vitamin D and light is king, don’t waste this precious sunlight. Supplemental vitamin D does not compare, it is not a vitamin, it’s a hormone that is synthesised from UV light onto the skin and we need the full spectrum. 

In the UK we don’t get much sun so you have to take every opportunity to get it while you can. I occasionally use special sunbeds (during a week of bad weather) that have the right ratio of UVA and UVB for my skin- it’s personalised and actually protects against many cancers, contrary to popular belief. If you use a standard sunbed this is not the same and can be very harmful, especially if used frequently. I only go once a week and only when the weather is terrible. 
I also now never wear sunglasses as I understand UV light going into the retina is very important for not just eye health but overall health. I won’t look directly at the sun, but make efforts to look in the direction of it. You can actually become more photosensitive if you wear sunglasses and may end up like Bono. This is why I will never wear sunglasses, and only blue blockers in artificial light at appropriate times. 
My first choice will always be to lie in the sun, on the ground and with my skin in contact with the ground. In future I’m looking to move to somewhere with more sun, less population, and less nnEMF, preferably none or next to nothing! Studies on constantly being exposed to EMF are inconclusive but it’s something that is very difficult to prove either way. It makes sense to me to have breaks from it though because it clearly has some effect on the brain and epilepsy. It also made me think of this glioblastoma study using electromagnetic radiation, slowing down cell division of tumour cells but what is it doing to the healthy cells? It really makes you think, or at least it makes me think!! I’ll stick with the good old sunshine thanks. 
I’m pretty sure humans are the only mammals that create our own artificial environments. Get out in nature as much as you can and expose as much of yourself to UV light as possible. Heliotherapy is huge, it’s healing by light and it’s nothing new. Artificial light damages health and messes up our natural circadian rhythms. If you think healing is all about food you are fooling yourself. Chronobiology, optogenetics, and heliotherapy is how we heal. Food is just one part of this, and is dictated by Chronotherapy. 
This is a pretty nice resource I like to use for information about chronobiology:

‘Grounding’ or ‘earthing’ and the science behind it…
‘Mounting evidence suggests that the Earth’s negative potential can create a stable internal bioelectrical environment for the normal functioning of all body systems. Moreover, oscillations of the intensity of the Earth’s potential may be important for setting the biological clocks regulating diurnal body rhythms, such as cortisol secretion.’

I would say eat plenty of oily fish and get sun, fish oil supplements are probably oxidised anyway due to the process it takes to make them so best to eat the fish themselves. Generally the quality fish oils can’t hurt (could be wrong), but if they smell fishy or are stored incorrectly they probably can. This is often why the companies that produce them add flavourings to disguise the rancid, fishy taste, especially with the cheaper brands.