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What are vitamins and what are their functions?

From the book: "The Complete Israeli Guide to Nutritional Supplements", by Yaffe Shir-Rez and Dr. Udi Bar, scientific editing - Anat Tuag, Keter Publishing, February 2008

From the introduction to the book

The cover of the book The Complete Israeli Guide to Nutritional Supplements by D
The cover of the book The Complete Israeli Guide to Nutritional Supplements by D
The nutritional supplements - vitamins, minerals, medicinal plants and fatty acids - have received unprecedented exposure and public awareness in recent years. 80 percent of the population of the United States and over a third of the population in Israel use nutritional supplements. This trend is steadily getting stronger every year - and not by accident. The discoveries made in recent years in this field are among the most fascinating and promising in the field of medical research today, and the countless studies being conducted on the subject reveal more and more essential key roles of the various nutritional supplements.

Until about a century ago, before the first vitamin was discovered, severe and mysterious diseases such as scurvy (due to vitamin C deficiency), beri-beri (due to vitamin B1 deficiency) and pellagra (due to niacin deficiency) caused the disabilities, blindness and death of millions of people. The explanation in the past among doctors was that these diseases were caused by an unknown pollutant or a hereditary disease. Only with the discovery of vitamins at the beginning of the twentieth century and the understanding of the importance of these nutrients to our health, were these deficiency diseases eradicated by simply adding a nutritional component or vitamin pill to the menu. Following these sensational discoveries, these diseases received a new name: "hypovitaminosis", or "diseases due to a lack of vitamins".

Today, in the western world, it is rare to find actual deficiency diseases resulting from a lack of vitamins and nutrients, but borderline deficiency levels are very common! National nutritional studies, carried out in the United States and other Western countries, repeatedly prove that most of us consume insufficient levels of vitamins, minerals and other nutritional factors, including vitamins 1B, 2B, 6B, 12B, folic acid, iron, calcium and magnesium. These deficiency levels are caused as a result of the western menu, which is mostly based entirely on processed foods, and includes too few fresh foods, vegetables and fruits. It is true that the borderline deficiency is not usually reflected in the distinct deficiency-diseases as in the past, but their damage to health is no less severe. Deficiency levels of one or another nutritional factor harm our body starting from the microscopic cellular level to severe and comprehensive damage to our health.

And so, nutritional supplements, which in the past were only used as a treatment for various deficiency diseases, have for a long time gone beyond their old purpose and are now used as central healing and prevention tools in a wide variety of different diseases and pathological conditions. Nutritional supplements are currently the most important tool in contributing to slowing down the wear and tear of many physiological systems in our body, including the bones of the skeleton, joint cartilage, skin, heart and blood vessels, as well as brain tissue and the nervous system.

In November 2007, the FDA (American Food and Drug Administration) published guidelines for the consumption of vitamins and nutritional supplements. From this important document, which marks a change in the attitude of the establishment towards the field of nutritional supplements, it appears that the FDA recognizes the importance of supplements in maintaining health and preventing disease.

The FDA experts also write that, according to the Academy of Family Physicians (AAFP), doctors should recommend supplements in cases of certain health problems, as well as for vegetarians and pregnant and lactating women. These things are reinforced in a recent survey conducted by "The Council for Responsible Nutrition" among medical professionals in the United States. The findings of the survey show that, contrary to the popular myth that medical professionals do not use nutritional supplements, 72% of doctors and 89% of nurses in the United States testified that they take supplements regularly.

There is no doubt that the science of nutrition has come a long way since the discovery of the first vitamin, but the impression among researchers is that the last word in this fascinating and important field has not yet been spoken. In the coming years, the use of nutritional supplements will increase, and already in the near future, family doctors in the community, doctors in the internal departments of hospitals, as well as dermatologists, ophthalmologists and other specialist doctors, will make intelligent use of nutritional supplements as part of their routine work with the patient population.

The book "The Complete Israeli Guide to Nutritional Supplements" was written with the aim of putting a scientific order on the topic of nutritional supplements and to provide extensive explanations about each of them. All the supplements chosen to appear in the book are already used today as components of advanced medicine applied in many medical institutions around the world.

The book is intended to expand the knowledge of all those who are hungry for health and also for the use of doctors and the various healing professions, who wish to sharpen their knowledge and skill in this new and fascinating medical field.

Shir-raz is beautiful

Introductory chapter: Vitamins

Vitamins are essential organic components that our body needs in minute amounts for its development and proper functioning, and without them life would not be possible.
The term "vitamins" is derived from the Latin word Vita, which means life, and was coined by a Jewish-Polish chemist named Dr. Kazimir Funk, who worked at the Lister Institute of Preventive Medicine in London.

In 1912, Dr. Funk published an article in a medical journal in England, in which he made a bold (albeit well-founded) hypothesis, which later became one of the foundations of the theory of nutritional science and a landmark in the history of medicine. His hypothesis, which was called the "vitamin hypothesis", was that most foods contain "mysterious" organic substances in tiny amounts, and that a lack of consumption of these substances causes various diseases, including beriberi disease, scurvy, pellagra and malaise - all diseases whose causes for many years were attributed to infections or for genetic diseases.

The vitamins assist in the performance of many biochemical processes in the body, such as the production of energy for the body's action, the building of tissues such as muscles and bones, the regulation of metabolism, the production of hormones and neurotransmitters, the construction of blood cells, the creation of the chemicals that activate the nervous system, assistance in digestive operations, and more. Some of the vitamins are even used as antioxidants that protect our bodies from the damage caused by chemically active molecules called free radicals. These are electrically charged active particles, which are created and accumulate in the body during metabolism and cellular respiration, or are produced by environmental factors, such as air pollution, smoking, exposure to the sun, and more. These free radicals are now considered the main cause of premature aging and as cancer-causing agents.

Vitamins are necessary for our bodies in trace amounts. Unlike nutrients such as carbohydrates and proteins, which are necessary for our bodies in large quantities measured in grams, the amounts in which vitamin consumption is measured are tiny - usually milligrams or even micrograms. Despite their relatively tiny weight in the body and their zero caloric value, without them, as mentioned, there would be no life at all.

The living body is not able to produce most of the vitamins by itself, so it needs their supply through food. Exceptions to this rule are vitamin D, which is created in the skin with the help of the sun's rays; vitamin K formed in the intestines with the help of bacteria; And also some vitamins from the vitamin B family. However, it is important to supplement the tiny amounts of these vitamins found in the body through food.

Some vitamins are obtained from food as inactive provitamins, and only in the body itself do they become real active vitamins. An example of this is beta-carotene, a plant pigment found in food and stored in our bodies. When the body needed a supply of vitamin A, it turns the plant pigment beta-carotene into active vitamin A and uses it for its needs.

Vitamins are usually divided into two groups: fat-soluble vitamins and water-soluble vitamins. The group of water-soluble vitamins includes vitamin C and the B vitamin family. The excess amounts of these vitamins are excreted through urine and sweat, and therefore most of these vitamins are not stored in the body.

The group of fat-soluble vitamins includes vitamins A, D, E, K. Unlike the water-soluble vitamins, the fat-soluble vitamins tend to be stored in our bodies, mainly in the fat tissues and the liver, and sometimes provide us with alternative reserves for the necessary vitamin levels even in times of deficiency. Some of them, in particular vitamins A and D, may be dangerous in overdose, and therefore it is advisable to be careful not to consume more than their recommended daily dose except under medical recommendation and supervision.

The many studies conducted on the various groups of vitamins and the many discoveries made on the subject in recent years have led to a re-examination of many processes and mechanisms in the body in which vitamins participate, and to the discovery of the crucial role that the various vitamins have in maintaining our health.

Furthermore, in the past the recommendations for taking various vitamins were based on doses intended to prevent the appearance of visible deficiency diseases (diseases caused by too low levels of vitamins), whereas today, following the results obtained from the new studies, it is recommended in most cases to take much higher doses. These dosages are intended to reduce the risk of the appearance of diseases and certain pathological processes, such as cardiovascular diseases, molecular degeneration, neurological damage, and more, which were previously not considered to be affected at all by a lack of vitamins.

Today, the appearance of overt deficiency diseases resulting from a clear deficiency of a certain vitamin are relatively rare. Pellagra and scurvy have almost disappeared from the world, but borderline deficiency levels in vitamins are still very common in the Western world and their damage to health can be just as severe. A lack of vitamins may result from a primary deficiency - as a result of poor nutrition - or alternatively from a secondary deficiency - as a result of various diseases.

Unlike most nutritional supplements, the amount of which is measured in milligrams/micrograms, the amounts of vitamins for treatment purposes are measured in units called International Units (IU). This unit of measure is also used to measure the quantities of various drugs (eg insulin), vaccines, hormones, blood products and other biological products. The international unit is based on measuring the biological effect of the substance, and is defined as the amount of substance necessary to produce an agreed biological response. This means that the exact definition of this unit varies from substance to substance - that is, each of the substances has a different value when converted to weight units of milligrams or micrograms (for example, one international unit of vitamin A is equal to 0.3 micrograms). The international units are based on international agreement, and their conversion values ​​to milligrams and micrograms have been determined by the Committee for Biological Standardization of the World Health Organization.

The standards for the recommended daily dose regarding the daily consumption of the nutrients, vitamins and minerals, were determined according to the recommendations of the food and health services in the USA and are referred to as the Recommended Daily Allowance (RDA). The RDA values ​​have been determined in the past and continue to be updated according to the findings of major medical studies, which yield new discoveries.

To the book page on the Keter website


  1. You helped me a lot, I appreciate your vigorous knowledge of me

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