Why Does The Body Need Sunlight?

As we all know, sunlight is vital to our survival. Through photosynthesis, plants produce oxygen and glucose for our bodies to function. But how exactly does sunlight interact with the human body?

As scientific technology has advanced over the centuries, we have begun to uncover the hazards that come with excess sun exposure. After all, we have all seen advertisements directing us to use the newest sunscreen with better and improved formulas, not to mention those warnings on beaches to wear sunglasses and hats. According to the Skin Cancer Foundation, unprotected exposure to ultraviolet (UV) radiation damages the DNA in our skin cells by introducing certain DNA-damaging molecules, such as hydroxyl and oxygen radicals. UVAs and UVBs are the two basic types of ultraviolet rays that reach the Earth’s surface. UVA rays are much stronger than UVBs and can penetrate the skin more deeply; still, UVBs can produce genetic defects or mutations that could ultimately lead to skin cancer (Chien, A., 202). Mark Nathaniel Mead, a holistic nutrition educator and NCBI writer, states that “excessive sun exposure can also cause cataracts and diseases aggravated by UVR-induced immunosuppression such as reactivation of some latent viruses” (Mead, M., 2021). If being exposed to the sun increases our risk of danger, would it not be better to stay inside for the rest of our lives?

One of the many benefits of exposing ourselves to sunlight is the production of vitamin D. Vitamins like vitamins A, B, and C can be obtained through food consumption while vitamin D is synthesized in the skin. Exposure to UVB radiation triggers a photosynthetic reaction that produces vitamin D. Simply put, UVB photons penetrate the skin to produce vitamin D from cholesterol, and the UVB rays themselves provide energy for vitamin synthesis (Healthline. 2021). The production of vitamin D can be affected by factors such as sunscreen, clothing, skin pigment, melanin, and excess body fat. Vitamin D is important, as it plays a crucial role in bone health and development. It comes as no surprise, then, that one can experience severe bodily issues if they do not produce enough of the vitamin. In children, a deficiency in vitamin D can cause rickets, a disease which is characterized by stunted growth and potential skeletal deformities (Mead, M., 2021). Vitamin deficiency can also result in diseases such as osteoporosis and osteomalacia. These bone-wasting diseases weaken bone strength, hence increasing the risk of fractures.

Most Caucasians would produce 50,000 international units (IUs) of Vitamin D while wearing a swimsuit under the sun for 30 minutes, while tanned people would produce 20,000–30,000 IUs under the same conditions. Dark skinned people, on the other hand, would produce 8,000–10,000 IUs (Healthline. 2021). IUs are a unit of measurement used to measure the amount of a substance, typically used to quantify for vitamins. It’s important to note that a higher amount produced doesn’t correlate to being worse but rather it determines how long an individual should be exposed. Dark skinned people produce less vitamin D IUs in the same length of time than Caucasians. This suggests that dark skinned individuals have the ability to stay in the sun for longer periods of time as compared to caucasians.

Not only does exposure to sunlight benefit our vitamin D production and bone development, but it also increases the brain’s release of a hormone called serotonin (Healthline. 2021). Sunlight and darkness both trigger different hormone releases in our brains. Darker lighting triggers the brain to make melatonin, a hormone that helps us sleep; meanwhile, brighter environments help us produce serotonin. Serotonin is responsible for boosting a person’s mood and creating a sense of calmness and focus (Healthline. 2021). Low serotonin levels may increase the risk of major depression. This can also be evident through seasonal affective disorder, otherwise known as SAD, which infers that seasons with lower daylight hours can affect serotonin levels.

Although the media has provided us with many reasons to limit exposure to the sun, sunlight is undoubtedly vital to our survival. However, too much sun exposure can still lead to sunburn and other serious health implications, such as skin cancer and eye damage. On the opposite side of the spectrum, it is evident that too little can result in vitamin D and serotonin deficiencies. Having a healthy balance between the two will keep your body healthy and less susceptible to health implications.

Works Cited:

Chien, A., 2021. UV Radiation - The Skin Cancer Foundation. [online] The Skin Cancer Foundation.

Available at: <https://www.skincancer.org/risk-factors/uv- radiation/#:~:text=UVA%20rays%2C%20while%20slightly%20less,darkening%2C%20resulting%20in%20a%20tan.> [Accessed 29 January 2021].

Healthline. 2021. How to Safely Get Vitamin D From The Sun. [online] Available at:

<https://www.healthline.com/nutrition/vitamin-d-from-sun#:~:text=When%20your%20skin%20i

s%20exposed,for%20optimal%20health%20(2).> [Accessed 29 January 2021].

Mead, M., 2021. Benefits of Sunlight: A Bright Spot for Human Health. [online] US National Library of

Medicine National Institutes of Health. Available at:

<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290997/> [Accessed 29 January 2021].

Nall, R., 2021. What Are the Benefits of Sunlight?. [online] Healthline. Available at:

<https://www.healthline.com/health/depression/benefits-sunlight> [Accessed 29 January

2021].

What is the difference between UVA and UVB rays? (2018, October 09). Retrieved February 20,

2021, from https://uihc.org/health-topics/what-difference-between-uva-and-uvb-rays

Cover Image: (Source: ePosts, The Benefits of The Sun For Humans, Animals and Plants)