I highly recommend watching this video: https://youtu.be/Kvh4D_osFXs Sunlight gives us vitamin D and nitric oxide (which improves blood flow and reduces hypertension). Vitamin D is crucial for the functioning of our immune systems, and the 1000IU dosage of many supplements is laughably small. A light skinned person in a singlet standing outside at noon for 30 minutes will produce between 10,000IU and 20,000IU in thei…
EPIC series of studies suggests dosage of 2000-3000 IU for all cause lowest mortality. (Europe, regardless of diet. Caucasian.)