Vitamins: What Are They and Are They Truly Essential for Our Health?

The term vitamin refers to a collection of organic compounds that an organism, although unable to produce in adequate quantities, still requires for significant bodily functions. To obtain these vital micronutrients, the organism must source them from suitable food. Since organisms produce these crucial molecules in different quantities, a nutrient that's essential for one species may not be scarce enough to be classified as a vitamin in another. For instance, dogs are capable of producing their own vitamin C in their livers, but fish, birds, guinea pigs, and humans cannot.

These compounds perform a multitude of functions, aiding an organism in growth, reproduction, and survival. Some function as signals, controlling the metabolism of other substances. Some assist enzymes in their operation, either directly as a cofactor or indirectly through the production of another.

Who were the pioneers in vitamin discovery?

The concept of vitamins was not established by a single breakthrough. By the late 19th century, the amalgamation of chemistry and biology had led to a series of revelations about the intricacies of human nutrition.

It became apparent to scientists that a healthy diet required more than just a correct balance of proteins, carbohydrates, fats, and minerals. Several research studies, many of which involved milk modification, suggested the presence of life-essential factors found in trace amounts.

In 1901, Dutch scientist Gerrit Grijns hypothesized that a nutrient deficiency could be behind the beri-beri epidemic in Indonesia. His colleague, Christian Eijkman's subsequent writings spurred a Polish biochemist with an impressively unique name, Kazimierz Funk, to delve further. He discovered a specific type of nitrogen compound (an amine) that he believed could combat the disease.

Funk's discovery of what he termed a 'vital amine', which would later be known as vitamin B3 or niacin, not only coined the term vitamin but also established the first concrete link between a disease and the absence of an essential organic micronutrient.

While beri-beri is actually caused by a deficiency in the closely related vitamin B1 (thymine), Funk's discovery ignited a series of research that linked various compounds with vital bodily functions.

What are some examples of vitamins?

For humans, there are just over a dozen compounds that are currently considered to be vitamins. Some are more easily soluble in fat, others in water, and can be found in select sources of meats, greens, nuts, and fungi. Here are some of the most common examples you may have taken in the past:

Vitamin A covers a small group of closely related compounds involved in regulating growth and development of cells throughout our body. Most active forms are retinol, retinal, and retinoic acid, with deficiencies having severe impacts on fetal development, immunity, and vision. Preformed vitamin A, or retinol, can be absorbed in the form of carotenoids in fruit and vegetables.

Vitamin B, or B complex vitamins, is a family of eight essential nutrients: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12). Their functions are closely related, activating enzymes that build up or break down other materials involved in things like DNA repair, energy production, and signaling molecules in the brain. Most can't be stored in the body, which means a healthy diet in things like greens, fish, eggs, and organ meats.

Vitamin C, or ascorbic acid, has a variety of roles in our body, from helping us absorb iron to wound repair, to removing reactive oxidative species. Since we can't retain large stores of the compound, it depletes quickly and needs to be replenished with a healthy diet of fruits and vegetables. Historically, its absence in fresh greens on long voyages has been linked with the disease scurvy - a condition eventually fixed with provision of longer-lasting citrus fruits and pickled cabbage. However, it is becoming increasingly common again in some of the world's richest countries.

Why are vitamins named after letters?

The American Academy of Pediatrics and the Centers for Disease Control and Prevention both advocate for newborns to receive a single shot of vitamin K at birth. This is because vitamin K is an essential nutrient used by the body to form clots and stop bleeding. Newborns are born with very low levels of vitamin K stored in their bodies, which can lead to a condition known as vitamin K deficiency bleeding (VKDB). This condition can cause serious and even life-threatening consequences, with one out of every five babies with VKDB dying. 

Vitamin K is especially critical for newborns because they do not produce enough of it naturally until they start eating solid food at about six months of age. Moreover, nursing mothers do not pass enough vitamin K in their breast milk to protect their babies from VKDB. 

The vitamin K shot has proven to be an effective preventative measure against VKDB, with no evidence supporting claims that it causes childhood cancer. Some countries offer an oral form of vitamin K, however, it is less effective than the shot at preventing bleeding, especially in the brain. 

The term Vitamin K is derived from the Danish spelling of coagulation, signifying its key role in the process of blood clotting. This is one of the reasons why it is so essential to newborns and why it is administered immediately after birth in many countries.

What is the recommended quantity of vitamins I should consume?

Despite vitamins being crucial for our wellbeing, a well-rounded contemporary diet usually supplies us with the necessary levels. Long-term use of daily multivitamin tablets has been found to have negligible benefits in numerous studies. If feasible, obtaining vitamins from your food is a better alternative.

Is it essential to consume a multivitamin daily?

Unless a medical professional has identified a specific vitamin deficiency in your body, it's not typically required to consume daily supplements for an extended duration.

Is it possible to overdose on vitamins?

Indeed, an excessive intake of vitamins can lead to health issues. Overconsumption of even water-soluble vitamins like vitamin C and vitamin B, which are not retained in the body, can induce symptoms such as diarrhea or heartburn. 

Moreover, excessive intake of some vitamins, like vitamin A, can lead to birth defects if consumed in high amounts during pregnancy.