Consequences of Avoiding the Sun

How avoiding the sun is making us ill

Consequences of Avoiding the Sun

How avoiding the sun is making us ill

Humans need sunlight. Critically, humans must be exposed to UVB radiation to create vitamin D in the skin.

Yet, in what might be regarded as the worst move in the history of human health, we have avoided the sun with no regard as to how this increases disease (including cancer) through the lowering of vitamin D levels. Almost all modern humans are deficient in vitamin D, and vitamin D levels have been falling in the population over recent decades, as people have increasingly avoided the sun and covered their skin.

The consequence of low vitamin D for the worldwide population has been severe. Low vitamin D levels are associated with almost all diseases, including heart disease, diabetes, infertility, cancers, autoimmune diseases, sepsis, obesity, mood disorders and viral infections. Indeed, lower levels of vitamin D are associated with more than 70 diseases and disorders.

This is because every cell in the body is designed to work with vitamin D and has a specific receptor for vitamin D. Thousands of our genes only function through vitamin D. These genes are responsible for important physiological functions, such as the regulation of our immune system, or the production of nerve growth factor when the brain needs to make a new connection, or the production of insulin for the pancreas, or the production of enzymes that make neurotransmitters, or the appropriate killing off of cells so that the cells do not become cancerous, or the regulation of our body fat. The low amount of vitamin D that we do have is largely used to ensure that we have sufficient calcium in the blood, which is a life-critical function, leaving insufficient vitamin D for other functions.

If our genes cannot tell our physiological systems what to do, then we inevitably see a broad range of disease.

Where are we at?

Most experts on vitamin D recognize that a person requires a blood 25(OH)D level of at least 50 ng/ml (125 nmol/L) to be healthy. Indeed, the body does not even begin to regulate its use of vitamin D until the blood 25(OH)D level reaches 40 ng/ml. Furthermore, although the body is designed to store vitamin D, such storage is not seen in most people because their limited vitamin D supply is used up immediately. Traditionally, the human species has had blood 25(OH)D levels of 50 to 70 ng/ml. All-cause mortality (due to dozens of diseases) decreases as the blood 25(OH)D level increases to at least 50 ng/ml. The optimal blood 25(OH)D level is likely to be between 50 and 100 ng/ml.

Yet more than half of a modern population will have a blood 25(OH)D level below 15 ng/ml.

We might survive with low levels of vitamin D, but our bodies cannot work as they are designed to at such low levels.

The solution to vitamin D deficiency

Although vitamin D in food appears to be used in the body in the same way as vitamin D created by sunlight in the skin, the amount of vitamin D that can be consumed from food is typically tiny compared with the amount of vitamin D produced by sunlight on the skin (e.g., by a factor of 50).

The solution is that we get midday sun on the skin as much as possible, without getting burnt (because malignant melanoma is a real risk, although one that reduces with more frequent exposure to the sun). However, most of us are unable to strip off and lie in the sun for a minimum of half an hour without sunscreen on a daily basis. Furthermore, many of us live at altitudes where sunlight is weak. And black people need 10 times the sun exposure required by white people to create the same amount of vitamin D. High-strength oral supplementation of vitamin D is therefore essential for most of the world's population, at least outside of summer months.