Vitamin

The vitamins (from the English vitamine, today vitamin, and this from the Latin vita 'life' and the suffix amine, a term coined by the biochemist Casimir Funk in 1912) are essential organic molecules for living beings in the form of micronutrients, since when ingested in the diet in a balanced manner and in essential doses, They promote the correct physiological functioning and metabolism. Most of the essential vitamins cannot be synthesized by the body, so it can only obtain them externally through a balanced intake of natural foods that contain them. Vitamins are nutrients that, along with other nutritional elements, act as catalysts for all physiological processes directly and indirectly.

A healthy diet rich in fruits and vegetables is a good source of vitamins.

Vitamins are precursors of coenzymes, (although not properly enzymes) prosthetic groups of enzymes. This means that the vitamin molecule, with a small change in its structure, becomes the active molecule, whether it is a coenzyme or not.

The minimum daily requirements for vitamins are not very high. Only milligram or microgram doses contained in large amounts (proportionally speaking) of natural foods are needed. Both deficiency and excess levels of vitamins in the body can cause diseases ranging from mild to serious and even very serious, such as pellagra or dementia, among others, and even death. Some can serve as an aid to the enzymes that act as a cofactor, as is the case with water-soluble vitamins.

Vitamin deficiency is called hypovitaminosis while excessive vitamin level is called hypervitaminosis.

It has been shown that group B vitamins are essential for the proper functioning of the brain and body metabolism. This group is hydrosoluble (soluble in water) due to this they are eliminated mainly in the urine, which makes it necessary to have a constant daily intake of all the “B” complex vitamins (contained in natural foods).

Classification of vitamins

In humans there are 13 vitamins that are classified into two groups: 9 water-soluble (8 B-complex and vitamin C) and 4 fat-soluble (A, D, E, and K).

Fat-soluble vitamins

Fat-soluble vitamins A, D, E, and K are eaten with foods that contain fat.

They are those that dissolve in fats and oils. They are stored in the liver and fatty tissues. Because they can be stored in body fat, it is not necessary to take them every day, so it is possible, after sufficient consumption, to survive for a time without their contribution.

If they are consumed in excess (more than 10 times the recommended amounts) they can be toxic. This can happen especially to athletes, who, although they maintain a balanced diet, resort to high-dose vitamin supplements, with the idea that they thus they can increase their physical performance.

These vitamins do not contain nitrogen, they are soluble in fat, therefore, they are transported in the fat of foods that contain it. On the other hand, they are quite stable against heat (vitamin C degrades at 90 °C into toxic oxalates). They are absorbed in the small intestine with dietary fat and can be stored in the body to a greater or lesser degree (they are not excreted in the urine). Given the storage capacity of these vitamins, a daily intake is not required.

Water-soluble vitamins

Water-soluble vitamins are those that dissolve in water. These are coenzymes or coenzyme precursors, necessary for many chemical reactions of metabolism.

These vitamins contain nitrogen in their molecule (except vitamin C) and are not stored in the body, with the exception of vitamin B12, which is stored to an important extent in the liver. The excess of ingested vitamins is excreted in the urine, for which a practically daily intake is required, since by not storing it, it depends on the diet. On the other hand, these vitamins dissolve easily in the food cooking water, so it is convenient to take advantage of that water to prepare broths or soups.

Health effects

Deficiency

Vitamin deficiency, avitaminosis or hypovitaminosis can cause more or less serious disorders, depending on the degree of deficiency, even leading to death. Regarding the possibility that these deficiencies occur in the developed world, there are very different positions. On the one hand, there are those who say that it is practically impossible for a vitamin deficiency to occur, and on the other, those who answer that it is quite difficult to reach the minimum vitamin doses, and therefore, it is easy to acquire a deficiency, at least mild.

Normally, those who claim that a vitamin deficiency is “unlikely” are in the majority. This majority group argues that:

• The needs of vitamins are minimal, and we must not worry about them, compared to other macronutrients.
• An abuse of vitamin supplements is done.
• In our environment a diet is made varied enough to meet all needs.
• The quality of food in our society is high enough.

On the contrary, it is answered that:

• The necessary amount of vitamins are small, but also the amounts found in foods.
• The deficiencies of any nutrient among the population of developed countries are not rare: iron and other minerals, antioxidants (very vitamin-related), etc.
• Vitamins are negatively affected by the same factors as other nutrients, to which others add: heat, pH, light, oxygen, etc.
• It is enough that the minimum recommendations to consume are not followed 5 servings of vegetables or fruits a day so that the basic daily needs are not met.
• Any factor that adversely affects food, such as residence changes, lack of time, poor nutritional education or economic problems, may cause some vitamin or other nutrient deficiency.
• The symptoms of severe avitaminosis have been well known for centuries. But it is not known as diagnosing a mild deficiency from its possible symptoms as they might be: the stretches in the nails, bleeding from the gums, memory problems, muscle aches, lack of mood, clumsiness, eye problems, etc.

For these reasons, one side recommends taking vitamin supplements if it is suspected that the necessary doses are not being reached. On the contrary, the other side sees it as unnecessary, and warns that abusing supplements can be harmful.

Hypervitaminosis and vitamin toxicity

Vitamins, while essential, can be toxic in large amounts. Some are very toxic and others are harmless even in very high amounts. The toxicity can vary according to the way of applying the doses. As an example, vitamin D is given in amounts high enough to cover 6 months' needs; however, the same could not be done with vitamin B3 or B6, because it would be very toxic. Another example is that long-term water-soluble vitamin supplementation is better tolerated because surpluses are easily eliminated in the urine.

The most toxic vitamins are D and A, and vitamin B3 can also be. Other vitamins, however, are very little toxic or practically harmless. B12 does not have toxicity even with very high doses. A similar thing happens to thiamine, however with very high doses and for a long time it can cause thyroid problems. In the case of vitamin E, it is only toxic with specific vitamin E supplements and with very high doses. There are also known cases of poisoning in Eskimos when eating marine mammal liver (which contains high concentrations of fat-soluble vitamins).

Recommendations to avoid vitamin deficiencies

The main source of vitamins are raw vegetables, therefore, the recommendation to consume 5 servings of fresh vegetables or fruits a day must be equaled or exceeded .

That is why we must avoid processes that cause excessive loss of vitamins:

• You have to avoid cooking food too much. A lot of temperature or for a long time.
• Earn the food that will be cooked, in the water already boiling, instead of taking the water to boil with them inside.
• Avoid food being prepared (cooked, stumbled or squeezed), long before eating.
• The skin of fruits or the shell of cereals contains many vitamins, so it is not convenient to remove it.
• Choosing food well when buying it. Better quality results in greater nutritional value.

Although most processing impairs vitamin content, some biological processes can increase the vitamin content in food, such as:

• The fermentation of bread, cheese or other foods.
• Making yogurt through bacteria.
• The cure of hams and sausages.
• The seedling, for salads.

Industrial processes usually destroy vitamins. But some can help reduce losses:

• The vapourized rice gets the vitamins and minerals from the shell to stick to the heart of the rice and don't miss out so much by removing the skin.You have to remember that the rice with peel has 5 times more vitamin b1 (and other vitamins) than the one that is peeled.
• The freezing produces losses in the quality of the molecules of some vitamins inactivating part of them, it is better to consume 100% fresh foods.
• UHT sterilization processes, very fast, prevent excess vitamin loss that a slower process may well neutralize the effect of some vitamin destructive enzymes such as those that are scattered in orange juice.

Not consuming vitamins at the appropriate levels (contained in natural foods) can cause serious illnesses.

Dietary recommendations

In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid risk of toxicity. For example, for vitamin C, recommended intakes range from between 40 mg/day in India and 155 mg/day for the European Union.

The table below shows the Estimated Average Requirements and Recommended Dietary Allowances (EAR and RDA respectively) for vitamins for the US, the Population Reference Intake (PRI) for the European Union (same concept as RDA), followed by what three government organizations consider the maximum safe intake. The RDA is set higher than the EAR to cover people with above-average needs. Adequate Intakes (AI) are established when there is not enough information to establish EAR and RDA. Governments are slow to review information of this nature. For US values, with the exception of calcium and vitamin D, all data are from 1997-2004.

EAR US: Estimated Average Requirements (Estimated Average Requirements).

RDA US: Recommended Dietary Allowances (Recommended Dietary Allowances); higher for adults than for children, and may be even higher for pregnant or lactating women.

AI US and EFSA AI: Adequate Intake (Adequate Intake); AIs are set when there is insufficient information to set EAR and RDA.

PRI: Population Reference Intake (Population Reference Intake) is the equivalent of the RDA of the European Union; higher for adults than for children, and may be even higher for pregnant or lactating women. For thiamine and niacin, the PRI is expressed as amounts per MJ of calories consumed. MJ = megajoule = 239 calories of food.

UL Upper Limit (Upper Limit): Tolerable upper intake levels.

ND: ULs have not been determined.

NE: EARs have not been set.

History

The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding a person liver could help cure night blindness, a disease now known to be caused by a deficiency of vitamin A. The advance of ocean voyages during the Renaissance resulted in Expeditions will spend long periods without access to fresh fruits and vegetables and will develop vitamin deficiency diseases, quite common among ship crews.

In 1747, Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen does not form properly, causing poor wound healing, bleeding gums, sore and eventually death. In 1753, Lind published his Treatise on the Scurvy, which recommended the use of lemons and limes to prevent it, a practice that was adopted by the British Royal Navy. (This gave rise to the nickname Limey for sailors in the Royal Navy.) Lind's discovery, however, was not accepted by everyone and in the Arctic expeditions of the Royal Navy itself, in the XIX century, instead of preventing scurvy with a diet of fresh foods, it was believed to prevent it with good hygiene, regular exercise, and maintaining crew morale on board. As a result, Arctic expeditions continued to be plagued by scurvy and other vitamin deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to Antarctica, the prevailing medical theory at the time it was that scurvy was caused by "contaminated" canned food.

Since the late 18th century and early XIX, using deprivation studies allowed scientists to isolate and identify a number of vitamins. The lipids in fish oil were used to cure rickets in rats, and thus the fat-soluble nutrients were named antirachitic A (antirachitic A). Thus, the first “vitamin” bioactive ever isolated, which cured rickets, was initially called “vitamin A”; however, the bioactivity of this compound is now called vitamin D. In 1881, Russian surgeon Nikolai Lunin (Лунин, Николай Иванович) studied the effects of scurvy while at the University of Tartu in present-day Estonia. He fed mice with an artificial mixture of all the separate milk constituents known at the time, viz., proteins, fats, carbohydrates, and salts. The mice that received only the individual components died, while the mice fed the milk itself developed normally. Lunin came to the conclusion that "a natural food, such as milk, must therefore contain, in addition to these known main ingredients, small amounts of unknown substances essential for life". However, his conclusions were rejected by other researchers—such as his adviser, Gustav von Bunge—when they were unable to reproduce his results. The difference was that he had used table sugar (sucrose), while other researchers had used milk sugar (lactose) which still contained small amounts of B vitamins. A similar result by Cornelius Pekelharing appeared in a medical journal. Dutch in 1905, but not widely reported.

In East Asia, where refined white rice was the common staple of the middle class, beriberi resulting from a lack of vitamin B₁ was endemic. In 1884, Takaki Kanehiro, an experienced Japanese physician, who had studied with other British Imperial Japanese Navy physicians, noted that beriberi was endemic among low-ranking crew who often ate only rice, but did not appear among officers. who ate a western-style diet. With the support of the Japanese navy, he experimented on the crews of two warships; one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. In the group that only ate white rice, 161 cases of beriberi and 25 crew deaths were documented, while in the second group there were only 14 cases of beriberi and no deaths. This convinced Takaki and the Japanese Navy that diet was the cause of beriberi, but they were wrong when they believed that sufficient amounts of protein would prevent it. That the diseases could be the result of some dietary deficiencies was further investigated. by Christiaan Eijkman, who in 1897 discovered that feeding brown rice instead of the refined variety for chickens helped prevent a kind of polyneuritis that was the equivalent of beriberi in chickens. The following year, Frederick Hopkins postulated that some foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, etc.—that were necessary for the functions of the human body. Hopkins and Eijkman were awarded the Nobel Prize in Physiology o Medicine in 1929 for his discovery of various vitamins.

From vitamin to vitamin

In 1910, the Japanese scientist Umetaro Suzuki managed to isolate the first vitamin complex, extracting a water-soluble complex of micronutrients from rice bran, which he called aberic acid (later Orizanin). He published this discovery in a Japanese scientific journal. When the article was translated into German, the translation did not state that it was a newly discovered nutrient (a statement that was made in the original Japanese article) and therefore its discovery took place. unnoticed. In 1912, the Polish biochemist Casimir Funk, then working in London, isolated the same micronutrient complex and proposed that the complex be called a "vitamin" (from "vital amine", a name suggested by Max Nierenstein, a friend and reader of biochemistry). at the University of Bristol.) It would later be known as vitamin B₃ (niacin), although he described it as "anti-beri-beri-factor" (which today would be called thiamine or vitamin B1). Funk hypothesized that other diseases, such as rickets, pellagra, celiac disease, and scurvy, could also be cured with vitamins. The name soon became synonymous with Hopkins' "accessory factors," and by the time it was shown that not all vitamins were amines, the word was everywhere. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to de-emphasize the "amine" reference, when researchers began to suspect that not all "vitamins" (particularly vitamin A) had an amine component. amine.

Nomenclature

The reason the vitamin pool jumps directly from E to K is that the vitamins corresponding to the letters F through J have been reclassified over time, discarded as red herrings, or renamed due to to its relationship with vitamin B, which became a complex of vitamins.

The Danish-speaking scientists who isolated and described vitamin K because the vitamin is intimately involved in blood clotting after injury (from the Danish word Koagulation). At that time, most (but not all) of the letters F through J were already designated, so the use of the letter K was considered quite reasonable. The table Reclassified Vitamin Nomenclature< /i> lists the chemicals that had previously been classified as vitamins, as well as the former names of the vitamins that later became part of the B complex.

Missing B vitamins were either reclassified or determined not to be vitamins. For example, B₉ is folic acid and five of the folates are in the range of B₁₁ to B₁₆. Others, such as PABA (formerly B₁₀), are biologically inactive, toxic or with unclassifiable effects in humans, or not generally recognized as vitamins by science, as well as higher numbers, than some physicians naturopaths call it B₂₁ and B₂₂. There are also nine lettered B vitamins (for example, B_m). There are other D vitamins that are now recognized as other substances, which some sources of the same type number up to D₇. The controversial cancer treatment laetrile was once called vitamin B₁₇. There appears to be no consensus on vitamins Q, R, T, V, W, X, Y, or Z, nor are there any substances officially designated as vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.

The one-paragraph article by Jack Drummond in 1920, which provides the structure and nomenclature used today for vitamins.

Nobel prizes for vitamin research

The 1929 Nobel Prize in Physiology or Medicine was awarded to Christiaan Eijkman and Sir Frederick Gowland Hopkins for their contributions to the discovery of vitamins. Thirty-five years earlier, Eijkman had observed that chickens fed polished white rice developed neurological symptoms similar to those seen in military sailors and soldiers fed a rice-based diet, and that the symptoms reversed when the chickens were switched to brown rice. He called this "the anti-beriberi factor," which was later identified as B₁, thiamine.

In 1930, Paul Karrer elucidated the correct structure of beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi's discovery of ascorbic acid and made important contributions to flavin chemistry, leading to the identification of lactoflavin. For their research on carotenoids, flavins, and vitamins A and B2, they both received the Nobel Prize in Chemistry in 1937.

In 1931, Albert Szent-Györgyi and one of his researchers Joseph Svirbely suspected that “hexuronic acid” was actually vitamin C, and gave a sample to Charles Glen King, who tested its efficacy against scurvy in trials with Guinea pigs. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967 George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for their discovery that vitamin A could be directly involved in a physiological process.

In 1938, Richard Kuhn received the Nobel Prize in Chemistry for his work on carotenoids and vitamins, specifically B₂ and B₆.

Five people have received Nobel Prizes for direct and indirect studies of vitamin B₁₂: George Whipple, George Minot and William P. Murphy (1934), Alexander R. Todd (1957) and Dorothy Hodgkin (1964).

History of promotional marketing

Once discovered, the vitamins were actively promoted in articles and advertisements in McCall's, Good Housekeeping, and other media outlets. Marketing enthusiastically promoted cod liver oil, a source of vitamin D, as "bottled sunshine," and bananas as a "natural vitality food." They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically determined nutritional value, rather than taste or appearance. World War II researchers focused on the need to ensure adequate nutrition, especially in processed foods. Robert W. Yoder is credited with first using the term vitamania, in 1942, to describe the appeal of relying on nutritional supplements rather than obtaining vitamins from a varied diet food. The constant concern for a healthy lifestyle has led to an obsessive consumption of additives whose beneficial effects are questionable.