Go Out and See the Sun

Three years had passed since the pandemic, and I couldn’t remember the last time I had basked in the golden rays of the sun. According to my doctor, I seemed to lack adequate vitamin D and needed to spend more time outside. However, I refused to accept the sun’s magical power to create this “essential nutrient.” Thus, I had no other choice but to ingest the small pill that somehow carried all the vital nutrients I needed. It didn’t make sense to me. If I needed more sunlight, why couldn’t I just gobble down a whole bottle of vitamins?

Confusing enough as it is, the definition of vitamins has been thrown around in the media, the medical community, and everyday life. Vitamins are organic medicines used to maintain one’s health, function, and development by influencing the body’s metabolic functions. Looking down store aisles, you have probably come across a huge variety of vitamins. Since different animals have different needs for vitamins and methods of synthesizing them, many vitamins have been uncovered. For instance, dogs naturally produce vitamin C, while humans have to obtain vitamin C from an outside food source. Amongst the variety of vitamins, the most essential to humans are vitamins A, B, C, D, E, and K. These vitamins are used in a variety of processes such as forming bones (A), brain function (B), wound healing (C), calcium absorption (D), blood cell formation (E), and coagulation of blood (K). To classify vitamins, labels of either fat-soluble (stored in the body and dissolving in fat) or water-soluble (not stored in the body and dissolving in water) are assigned to them. Many of these vitamins are found within one’s daily diet, existing in commonly eaten foods. Even though these vitamins are all crucial to one’s health, vitamin D still reigns number one. 

Vitamin D has many crucial functions, including helping your bones absorb calcium; providing anti-inflammatory, antioxidant, and neuroprotective properties to support immune health; and regulating muscle function. Of these functions, its effects on the immune system are arguably the most important, producing high levels of proteins that help fight infections. Traditionally, it’s been used in medical practices to lower the risks of infections and treat diseases like tuberculosis. On the other hand, vitamin D deficiency has also been proven to cause many autoimmune diseases. Not only is this vitamin crucial for the immune system, it’s also a major player in calcium homeostasis. In the presence of vitamin D, the small intestine absorbs calcium, thus allowing for proper maintenance of the bone structure. The next time you’re gulping down cartons of milk, make sure to drink some orange juice to increase both your calcium and vitamin D levels (this is a joke; you’ll get a painful stomach ache)! Surprisingly, more than 60 percent of the U.S. population is said to be deficient in vitamin D (lower than 20 ng/mL of blood). Being deficient also increases the risk of fractures alongside muscle weakness and muscle wasting—the reduction of the size and weight of muscle tissue. This is one of the main reasons why older people with vitamin D deficiency are extremely susceptible to injuries—they aren’t able to maintain proper muscle and immune function. 

Playing such an important role in the human body, vitamin D receives its own special production pathway. First, sunlight converts cholesterol in the skin to a form of pre-vitamin D₃. As the name suggests, the pre-vitamin D₃ is then turned into vitamin D₃ through UVB radiation (one of the three types of UV radiation from the sun). The liver then chemically adds a hydroxyl group (OH^-) to the vitamin D₃, creating 25-hydroxyvitamin D. Most cells have the ability to turn 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D directly, as it provides a more efficient way of intaking vitamin D. But the kidneys are also a viable method of turning this molecule into its active form. Knowing this pathway, scientists were able to piece together why vitamin D levels fluctuate. For instance, there are fewer hours of sunlight in the winter, which means less vitamin D can be synthesized from the sun. To solve the issue, dietary supplements were created during the early 1900s. They included a variety of components, such as vitamins and minerals. Through meticulous experimentation, scientists also figured out which foods contain vitamin D. Once this was revealed to the public, confusion and misinformation spread regarding vitamin D, causing mass vitamin D poisoning from excessive consumption of foods and supplements. Today, the use of supplements has grown from treating diseases to being popularly recommended in intense workouts to rebuild torn muscles quicker. 

The downside of supplements is their similarity to medicines, as they come with similar side effects. For example, overdosing on vitamins, such as by eating a whole bottle of vitamin D supplements, may cause organ malfunction, heart problems, and even death. Interestingly, natural absorption of the sun maintains a proper balance of vitamin D within the body. Excess pre-vitamin D₃ is automatically degraded through a process known as photodegradation. Photodegradation causes a molecule to be chemically altered using photons—particles of light energy—mainly from the sun. Additionally, supplements can also interfere with traditional treatments like blood thinners or chemotherapy through unwanted binding to these drugs, negating their effectiveness. Finally, the variety of supplements acts as a double-edged sword, as the effects of overdoses change depending on the vitamin. For instance, vitamin D, a fat-soluble vitamin, is more potent than vitamin C, a water-soluble vitamin, as it is not as easily excreted from the body. Fat-soluble vitamins dissolve in body fat, making intoxication treatment extremely difficult without long-lasting side effects. 

Vitamins are crucial for everyday function and survival for all organisms. Without maintaining the correct balance of vitamins, we would constantly get sick due to weakened body systems. Eating supplements alone can not substitute a healthy diet, as they only complement diet and pre-existing biological processes. As with any medication, supplements should only be taken with the advice of a medical practitioner. And if vitamin D supplements aren’t your thing, maybe it’s time to get outside and let the sun work its not-so-mysterious magic.