“Unlike other essential vitamins, which must be obtained from food, vitamin D can be synthesized in the skin through a photosynthetic reaction triggered by exposure to UVB radiation,” states a report from the National Institute of Health.
The initial photosynthesis produces vitamin D3, which regulates “at least 1,000 different genes governing virtually every tissue in the body.” Further transformations occur, generating forms of vitamin D which regulate calcium absorption and promote bone health.
With Victorian social norms mandating the avoidance of exposed skin, “By the late 1800s, approximately 90% of all children living in industrialized Europe and North America had some manifestations” of rickets – skeletal deformity due to low bone health.
With already low sunlight levels in these Northern climates, the addition of clothing layers proved unconducive to one’s health.
High vitamin D levels have been found to reduce the risk of tuberculosis, and could be linked to lower levels of cancer – except, of course, skin cancer. Other studies tie low vitamin D levels to everything from multiple sclerosis to hypertension.
Sunlight also plays a key role in the body’s production of Serotonin – or, as my sister used to call it, “the happy drug.” Low levels of this neurotransmitter have been correlated with “higher levels of irritability, impulsivity, aggression, disordered eating, and sleeping problems.”
Too much sun exposure can be bad, of course, but photosynthesizing vitamin D seems to have a lot going for it.
But really what I’m trying to say is – man, isn’t it nice out?