Excellent point! Yes, I read research about sunlight chaning the levels of nitric oxide in the body. Since it is a controversial topic I did not add it in my safe option list. I plan to write remarkable benefits of sunlight for health as I benefited from it with diligence and caution. Unfortunately due to valid reasons there is a massive fear of sunlight which needs to be clarified systematically. Thank you for adding this great point that enhances the meaning of my story.