In daily life, every person has a varied and complex diet. This diet includes fast foods devoid of fiber and protein, and other foods, rich in vitamins and minerals. One of the necessary components for the realization of biochemical processes is vitamins. It is either not synthesized at all or very little synthesized by organisms. For this reason, it must be taken from the foods. While taking these foods, it is also necessary to pay attention to the dose. Because too little or too much is a precursor to many diseases1.
Vitamins function by participating in the structure of enzymes or proteins in metabolism. They are usually easily broken down and excreted from the body. Therefore, the body can easily tolerate high doses. But for vitamin D, this is an exception. Too much can lead to various diseases and even death2. Before getting to this point, how can we get vitamin D?
To understand vitamin D, also known as the sunshine vitamin, it is important to understand sun rays well. Some of the energy produced by the sun is called Ultraviolet (UV). And because of the wavelengths they have, UV rays are not seen by humans but can be felt. The UV light associated with aging is diversified as UVA, and the UV light associated with burning is UVB. Although both are harmful to the skin and are proven to be carcinogens, the damage from the sun can be reduced to a minimum with the precautions taken3.

UVA acts on the skin’s lower surface and causes cancer, while UVB is (associated with Sun Protection Factor (SPF)) working on the upper layers of the skin. Also, the hours when UVB is most active are late morning to mid-afternoon. As for vitamin D activation, we must consider UVB because of its effect on the epidermis3. The figure below is an easy way to understand this.

Vitamin D is a group of sterols with important functions for the body. And is also called calciferols. Among the most important are D3, called cholecalciferol; and D2 called ergocalciferol. As a source, vitamin D can be obtained from the diet or made endogenously. Along with diet, it is mostly obtained from fish, liver, and eggs. As endogenously, it is synthesized from 7 dehydrocholesterol. Sunlight is needed for the transformations and activation of this. Vitamin D3 is not active on its own, its active form is 1,25(OH)2D3. However, 25(OH)D levels should be checked to determine vitamin D in the blood5, not 1,25(OH)2D3.
Vitamin D has hormone-like functions. It provides the balance of Calcium (Ca) and Phosphorus (P) in the body. It also affects the level of Parathormone for Calcium. Studies have shown that vitamin D is an undeniable factor in bone development. Its deficiency causes bone demineralization, which leads to rickets in children, and osteomalacia in adults2.
In addition to these diseases, an increase in Type-1 diabetes, multiple sclerosis, various cardiovascular diseases, and cancer has been observed in vitamin D deficiency. Similarly, an excess of vitamin D creates a toxic effect on the body6.

On the other hand, we know how effective the sun’s rays are for all these. But there are some misunderstood facts about this subject. For example, using sunscreen will cause vitamin D deficiency. But the truth is that this situation causes many problems indeed. Studies show that regular using of sunscreen reduces the incidence of squamous cell carcinoma (SCC) by 40%. And it helps maintain vitamin D levels. It will be sufficient to expose various parts of the body to the sun for 10-15 minutes a few days a week to get the necessary sunlight7.
Even for an ordinary person, the sun’s rays cause damage when exposed for a long time. This risk is greater for people with certain characteristics. The group that should pay more attention to sun exposure: are children; immunosuppressed people; people at risk of skin cancer; people with fair skin, red hair, and blue-green eyes. It has been observed by statistics that people in this group have a very high risk of developing skin cancer from exposure to the sun8.
People should be made aware of the content of being safe in the sun and staying healthy. In this regard, local campaigns can be organized to explain the risks and benefits. In this way, misunderstandings can be corrected, individuals at risk can be careful, and people can understand the relationship between sunbathing to their health.
References:
- Munzuroğlu, Ö., Karataş, İ. K. R. E. T., & Gür, N. A. Z. M. İ. (2000). Işgın (Rheum ribes L.) bitkisindeki A, E ve C vitaminleri ile selenyum düzeylerinin araştırılması. Turkish journal of biology, 24(3), 397-404.
- AKKOYUN, H., Bayramoğlu, M., Suat, E. K. İ. N., & Çelebi, (2014). D vitamini ve metabolizma için önemi. Atatürk Üniversitesi Veteriner Bilimleri Dergisi, 9(3).
- Skin Cancer Foundation – UV Radiation & Your Skin – Reviewed by:Anna Chien, MD / Heidi Jacobe, MD – Last updated: August 2021 https://www.skincancer.org/risk-factors/uv-radiation/
- Holick, M. (2003). Vitamin D: A millenium perspective. Journal of cellular biochemistry, 88(2), 296-307.
- Öngen B., Kabaroğlu C., Parıldar Z., 2008. D vitamininin biokimyasal ve laboratuvar değerlendirmesi. Türk Klinik Biyokimya Dergisi,6, 23-31.
- Yeşiltepe-Mutlu, G., & Hatun, Ş. (2011). Perinatal D vitamini yetersizliği. Çocuk Sağlığı ve Hastalıkları Dergisi, 54, 87-98.
- Skin Cancer Foundation – Sun Protection and Vitamin D – MAY 14, 2018 – By ANNE MARIE MCNEILL, MD, PHD, and ERIN WESNER – Receive Date: 31.10.2022 / 22.51 https://www.skincancer.org/blog/sun-protection-and-vitamin-d/#:~:text=When%20you r%20skin%20is%20exposed,active%20form%20of%20vitamin%20D
- National Institute for Health and Care Excellence (NICE) – Vitamin D: supplement use in specific population groups – Public health guideline [PH56] Published: 26 November 2014 Last updated: 30 August 2017 https://www.nice.org.uk/guidance/ph56
Figure References:
- Wexford Skin Clinic – Girls Just Wanna Have Sun – 09/07/2018 – by wexskinclinic – https://www.wexfordskinclinic.ie/girls-just-wanna-have-sun/ Receive Date: 22.50 / 10.2022
- Clark, A., & Mach, N. (2016). Role of Vitamin D in the Hygiene Hypothesis: The Interplay between Vitamin D, Vitamin D Receptors, Gut Microbiota, and Immune Response. Frontiers in immunology, https://doi.org/10.3389/fimmu.2016.00627
- 58 GrassrootsHealth Nutrient Research Institute – What is Vitamin D Good For? https://www.grassrootshealth.net/document/interactive-pdf-vitamin-d-deficiency-affect s-every-part-body/ Receive Date: 31. 10.2022 / 22.58
Inspector: Nadir KERESTECİ