Upgrade your knowledge, part 3 - Vitamins
Essential nutrients
Vitamins are organic compounds that are essential for growth, maintenance and proper functioning of the body. Thus, like the macronutrients proteins, carbohydrates and fats, the micronutrient vitamins are essential to the body. Vitamins generally cannot be synthesized, or cannot be synthesized sufficiently, in the body and therefore must be obtained from food or supplementation.
Vitamins are therefore called essential nutrients. They regulate numerous biochemical processes in the body. This requires relatively small amounts. However, without the presence of these tiny substances, our body cannot function properly. A good vitamin status in the body requires a very healthy and varied diet as well as a good absorption capacity of the body.
Vitamins have always been essential to life
It seems that vitamins were essential for life from the very beginning about four billion years ago. Early life forms could make their own vitamins. Certain species, including humans, lost that ability later. Diverse organisms thus became dependent on each other for vitamins. This created a complex flow of molecules that scientists have called "vitamin traffic. Vitamins are perhaps the best known and historical examples of biological molecules involved in intracellular traffic.
The primordial soup of life
Research has also been done in the ocean, the primordial soup of life. It has been discovered that some microbes produce organic growth factors that other organisms use. Vitamins are also found in the ocean, although they are difficult to detect. Oceanographers wonder why vitamins occur in the ocean. For example, why are they more prevalent in one part than another? And why exactly is a particular vitamin common at a certain latitude?
Presumably, certain organisms in parts where picomolar concentrations of vitamins are present are auxotrophic to those vitamins but need them. Auxotrophy means that an organism does not have the biosynthetic pathway necessary to make the vitamin itself and thus depends on other organisms that can. In any case, the scarcity of vitamins in some parts of the ocean and their dynamic variation are important reasons for further research into vitamin traffic.
Living cells
Every vitamin is made by living cells. Vitamin D, for example, is produced in our skin when sunlight interacts with a precursor of cholesterol. Making a vitamin is often a hugely complex process. In some organisms, as many as twenty-two different proteins are needed to make a vitamin B12 molecule. While a protein may consist of thousands of atoms, a vitamin may consist of only a few dozen atoms. And yet, despite their small size, vitamins make more possible biochemically in our bodies. For example, vitamins work with proteins to create reactions that proteins alone cannot evoke. Vitamin B1, for example, helps proteins extract carbon dioxide from molecules.
Universal chemistry in all living things
Vitamins facilitate biochemical reactions not only in our own bodies, but in all living organisms: bacteria, fungi, plants, humans. This universal chemistry is probably the result of evolution. Once the ability to make vitamins evolved, some species became particularly good at it. Plants, for example, evolved into vitamin C factories with plenty of vitamin C in their leaves and fruit. Initially, vitamin C probably helped plants defend themselves against stress - a function it performs in other species, such as humans. Over time, the vitamin took on new tasks in plants, such as helping to ensure that fruits develop.
These evolutionary developments usually do take hundreds of millions of years, but it can also be faster. Our own ancestors needed only thousands of years to change their production of vitamin D. When humans left equatorial Africa and spread to higher latitudes, the sun was lower in the sky and provided less ultraviolet light. By developing lighter skin, even the Europeans and Asians of the time retained the ability to produce vitamin D.
Vitamins have become essential
Humans today can hardly make the vitamins they need to stay healthy. Our ancestors in the very distant past could synthesize some vitamins themselves, such as vitamin C. However, they lost that skill. So humans too have become auxotrophic to by far most vitamins. We lack the biosynthetic pathways in our bodies to synthesize the vitamins and therefore must obtain vitamins from external sources. That makes them essential substances.
Burden of proof for the existence of vitamins
The first evidence for the existence of vitamins and the fact that they are essential came to light in the late 19th century in the work of Dutch physician Christiaan Eijkman. In 1890, his laboratory chickens developed a nervous disease (polyneuritis). This disease was similar to polyneuritis resulting from the deficiency disease beriberi. He proved in 1897 that the polyneuritis was caused by the chickens' imperfect diet of polished rice. The disease disappeared when he gave the animals unpolished rice.
Additional factors
In 1907, British biochemist Sir Frederick Gowland Hopkins noted that animals could not synthesize certain amino acids. He also concluded that macronutrients and salts alone were not sufficient for proper growth. In 1912, he published his findings on missing nutrients, which he then described as "additional factors," the later vitamins. For this work he and Christiaan Eijkman were awarded the Nobel Prize in Physiology or Medicine in 1929.
Vital factor or vital amines
At the same time, a Polish scientist Casimir Funk had a similar theory based on research in animals. Polyneuritis would also occur, according to him, because of a lack of a vital factor in the feed. Funk believed that certain diseases in humans, such as beriberi, scurvy and pellagra, were also caused by deficiencies in these same biochemical substances.
Because each contained a nitrogen atom known as an amine, Funk called the compounds "vital amines. He later shortened this term to "vitamins. The last e was later dropped (in English it became 'vitamins'), when it was discovered that not all vitamins contain nitrogen and therefore not all are amines. Finally, in 1926, this vital factor could be isolated for the first time and was named vitamin B, now B1.
Water and fat soluble
Vitamins are referred to by letters of the alphabet and by chemical names, such as niacin and folic acid. Biochemically, two groups can be distinguished, the water-soluble vitamins (these are mainly in the moisture of foods; vitamins B1, B2, B3, B5, B6, B8, B11, B12 and C) and the fat-soluble vitamins (mainly in fat of foods; vitamins A, D, E and K). In total, we know of thirteen vitamins. The body cannot store water-soluble vitamins and excretes excess. Fat-soluble vitamins are more difficult to excrete in excess.
Regulators of biochemical reactions
Vitamins regulate a variety of biochemical processes in the body, such as in the endocrine system and metabolism. Whereas macronutrients - fats and carbohydrates - are used directly as fuel for energy metabolism and proteins are converted into amino acids as building blocks, these metabolic processes are regulated to a large extent by vitamins. If a vitamin is not present, it can block specific metabolic processes in a cell and can ultimately interfere with metabolism in a cell and throughout the organism.
Catalytic function water-soluble vitamins
With the exception of vitamin C (ascorbic acid), all water-soluble vitamins have catalytic functions; that is, they function as coenzymes or cofactors of enzymes involved in energy transfer or in the metabolism of fats, carbohydrates and proteins. Thus, they are important for releasing energy from food, and for forming building blocks for body tissues.
Fat-soluble vitamins for cell membranes
Fat-soluble vitamins also have a variety of functions in the body. Some fat-soluble vitamins are part of the structure of cell membranes or help maintain the stability of cell membranes. Other fat-soluble vitamins function at the genetic level by regulating the synthesis of certain enzymes.
Interactions
Vitamins and vitamin and other food components have interactions with each other. The interactions can be synergistic, or mutually reinforcing, or antagonistic, for example, due to overlapping metabolic or protective functions. Also, certain vitamins depend in their action on the presence of other vitamins.
Nutrition and vitamin requirements
Vitamins are not found uniformly in foods. Vitamin A and D3, for example, are found only in animal foods. Beta-carotene, which can be converted into vitamin A in the body, for example, is synthesized only in plants. Both plant - vegetables, fruits, nuts -, and animal foods are therefore important natural vitamin sources for humans. The more restricted an individual's diet, the more likely a person is to lack certain vitamins.
All vitamins are synthesized from food after ingestion in the body. Food processing reduces the amounts of vitamins. Loss of vitamins can also occur when food is cooked. The amount of vitamins required by humans is difficult to determine. Factors such as age, living environment, strain, (environmental) stress and gene polymorphisms can all influence it. The recommended daily amounts of vitamins take into account individual variation and normal environmental stress. In certain situations, supplementation with vitamins may be a good idea. We would be happy to advise you.