Current sunscreen guidelines 

Vitamin D is essential for calcium absorption and many other biological processes. Lower levels of Vitamin D increase the rates of almost every disease like cancer, diabetes, osteoporosis, cognitive impairment, autoimmune conditions and more.

Vitamin D is a hormone manufactured by the skin when you are in the sun. It is difficult to obtain enough through diet. 

Getting vitamin D through supplementation shows zero benefits. A study over a period of 5 years found supplementing with Vitamin D had no impact on cancer, heart disease, or stroke.

A number of researchers now argue that people with high vitamin D levels are healthy not because of the vitamin, but because they get plenty of exposure to the sun. Vitamin D is just a marker of that fact.

A dermatologist discovered our skin uses sunlight to make nitric oxide, a molecule in the body that dilates blood vessels and lowers blood pressure.

He exposed volunteers to the equivalent of 30 minutes of summer sunlight without sunscreen. The result? The nitric oxide levels in the volunteers went up, and their blood pressure lowered. Because of the connection of high blood pressure to heart disease and strokes, this discovery can prevent millions of deaths globally.

Sun rays do increase the rate of skin cancer, but for every one person that dies of skin cancer, over 100 die from cardiovascular disease.

• People who get carcinomas tend to be healthy people that get plenty of sunlight. Carcinomas are seldom fatal.
• Melanoma, the deadly type of skin cancer, accounts for 1 - 3 % of new skin cancers. The most significant cause of melanomas is sporadic sunburn.

Sunlight triggers the release of serotonin and endorphins. It reduces the risk of prostate, breast, colorectal, and pancreatic cancers. It reduces inflammation and decreases autoimmune responses.

They are problematic. The SPF rating in sunscreen refers only to the UVB rays that cause sunburn but not the UVA rays that cause skin cancer. Many users may be absorbing far more UVA radiation than they are aware of.

Many sunscreen ingredients have hormone disruptors that can be detected in users' blood and breast milk. The worst, oxybenzone, is killing coral reefs by mutating the DNA of corals. It has been banned in Hawaii.

Cancer Council of Australia states that ultraviolet radiation from the sun is beneficial to human health but that a balance is required between excessive sun exposure and enough sun exposure to maintain adequate vitamin D levels and gain the many other benefits sunlight has to offer.

New Zealand signed on to similar recommendations, and the British Association of Dermatologists stated that people should enjoy the sun safely while taking care not to burn.