Vitamins: A Complete Collection of Misconceptions
We will not describe the history of the discovery of vitamins and retell how each of them affects the many biochemical processes that occur in the body. Let us devote this article to practical issues that everyone knows everything about, that which in the field of vitamin therapy is considered by patients and even doctors to be the truth, and that in fact is absolutely untrue. Let's start with the most important and harmful misconception.
Myth 1 . The need for vitamins can be fully met through good nutrition.
It is impossible - for a number of reasons. First, man too quickly “descended from a monkey”. Modern chimpanzees, gorillas, and our other relatives all day stuff their belly with a huge amount of plant food, while plucking it directly from a tree in a tropical forest. And the content of vitamins in wild tops and roots is ten times higher than in cultivated ones: agricultural varieties were selected for thousands of years not by their usefulness, but by more obvious signs - yield, satiety and disease resistance. Hypovitaminosis was hardly the No. 1 problem in the diet of ancient hunters and gatherers, but with the transition to agriculture, our ancestors, providing themselves with a more reliable and abundant source of calories, began to experience a lack of vitamins, minerals and other micronutrients (from the word nutricium - nutrition). As far back as the 19th century in Japan, up to 50, 000 poor people, who ate mostly peeled rice, died every year from beri-beri - vitamin B1 deficiency. Vitamin PP (nicotinic acid) in corn is contained in a bound form, and its predecessor, the essential amino acid tryptophan, is negligible, and those who fed only tortillas or mamaliga were sick and were dying of pellagra. In the poor countries of Asia, at least one million people die each year and half a million go blind due to the fact that rice does not have carotenoids - precursors of vitamin A (actually vitamin A is most found in the liver, caviar and other meat and fish products, and the first a symptom of his hypovitaminosis is a violation of twilight vision, "night blindness").
Vitamin educational program
Vitamins (lat. Vita - life) are low molecular weight organic compounds that are not synthesized in the human body (or are not synthesized in sufficient quantities) and are an active part of many enzymes or starting materials for the synthesis of hormones. A person’s daily need for various vitamins ranges from a few micrograms to tens of milligrams. Vitamins no longer have any common signs, it is impossible to separate them into groups either by chemical composition or by mechanisms of action, and the only generally accepted classification of vitamins is to divide them into water and fat soluble ones.
By structure, vitamins belong to the most diverse classes of chemical compounds, and their functions in the body are very diverse - not only in different vitamins, but also in each individual. For example, vitamin E is traditionally considered primarily necessary for the normal functioning of the sex glands, but this role at the level of the whole organism is only the first in time of discovery. It protects the unsaturated fatty acids of cell membranes from oxidation, promotes the absorption of fats and, accordingly, other fat-soluble vitamins, acts as an antioxidant, neutralizing free radicals, and thereby prevents the formation of cancer cells and slows down the aging process, etc. (to understand how he does this, you first need to learn a three-kilogram biochemistry textbook). For most other vitamins, the most visible symptom with the naked eye is also considered the main one, according to which it was once discovered. So the belief that vitamin D helps against rickets, C from scurvy, B12 is necessary for hematopoiesis, etc. is another common misconception about vitamins.
Water-soluble vitamins are Vitamin C (ascorbic acid), P (bioflavonoids), PP (nicotinic acid) and B vitamins: thiamine (B1), riboflavin (B2), pantothenic acid (B3), pyridoxine (B6), folacin, or folic acid (B9), cobalamin (B12). Fat-soluble vitamins include vitamins A (retinol) and carotenoids, D (calciferol), E (tocopherol) and K. In addition to 13 vitamins, approximately the same amount of vitamin-like substances is known - B13 (orotic acid), B15 (pangamic acid), H ( biotin), F (omega-3-unsaturated fatty acids), para-aminobenzene acid, inositol, choline and acetylcholine, etc. In addition to the vitamins themselves, multivitamin preparations usually contain organic trace elements - substances that the human body needs to be negligible (no more than 200 mg to DAY) to lichestvah. The main of the approximately 30 known trace elements are bromine, vanadium, iron, iodine, cobalt, silicon, manganese, copper, molybdenum, selenium, fluorine, chromium and zinc.
Moderate and even pronounced hypovitaminosis in Russia is present in no less than three quarters of the population. A close problem is dysmicroelementosis, an excess of some and a lack of other trace elements. For example, moderate iodine deficiency is a widespread phenomenon, even in coastal areas. Cretinism (alas, only as a disease caused by the lack of iodine in water and food) now does not occur, but, according to some reports, a lack of iodine reduces the intelligence coefficient by about 15%. And it certainly leads to an increase in the probability of thyroid disease.
A soldier of the pre-revolutionary Russian army, with daily energy expenditures of 5, 000-6, 000 kcal, was entitled to daily allowance, including, inter alia, three pounds of black bread and a pound of meat. One and a half to two thousand kilocalories, which are enough for a day of sedentary work and lying rest, guarantee you a shortage of about 50% of the norm of about half of the known vitamins. Especially in the case when calories are derived from refined, frozen, sterilized products, etc. And even with the most balanced, high-calorie and "natural" diet, the lack of certain vitamins in the diet can reach up to 30% of the norm. So take multivitamins - 365 tablets per year.
Myth 2 . Synthetic vitamins worse than natural
Many vitamins are extracted from natural raw materials, such as PP from citrus peel or B12 from a culture of the same bacteria that synthesize it in the intestine. In natural sources, vitamins are hidden behind the cell walls and bound to the proteins whose coenzymes they are, how much you digest and how much they disappear depends on many factors: for example, fat-soluble carotenoids are digested an order of magnitude more completely from carrots, finely grated and stewed with emulsified fat with sour cream, and vitamin C, on the contrary, quickly decomposes when heated. By the way, do you know that when natural rosehip syrup is evaporated, vitamin C is completely destroyed and only at the last stage of preparation is synthetic ascorbic acid added to it? In a pharmacy with vitamins, nothing happens until the end of the shelf life (and in fact, a few more years), and in vegetables and fruits, their content decreases with each month of storage, and even more so when cooked. And after cooking, even in the refrigerator, even faster: in a chopped salad, after a few hours, the vitamins become several times less. Most vitamins in natural sources are present in the form of a number of substances similar in structure, but different in effectiveness. Pharmaceutical preparations contain those variants of the molecules of vitamins and organic compounds of trace elements that are easier to digest and act most effectively. Vitamins obtained by chemical synthesis (like vitamin C, which is made both bio-technological and purely chemical), are no different from natural ones: in structure they are simple molecules and there simply can’t be any “life force” in them.
Myth 1 . Horse doses of vitamin ... help from ...
Articles on this topic regularly appear in the medical literature, but after 10−20 years, when scattered studies on different population groups, with different dosages, etc., accumulate enough to conduct a meta-analysis, it turns out that this is another myth. Typically, the results of this analysis are as follows: yes, a lack of this vitamin (or other micronutrient) is associated with a greater frequency and / or severity of this disease (most often with one or more forms of cancer), but the dose is 2-5 times exceeding the physiological norm, does not affect either the incidence or the course of the disease, and the optimal dosage is approximately the same as that indicated in all directories.
Myth 2 . A gram of ascorbic acid per day protects against colds and in general from everything in the world.
Twice, Nobel laureates are also mistaken: hyper-and megadoses of vitamin C (up to 1 and even 5 g per day at a norm of 50 mg) that have come into fashion with Linus Pauling’s supply, as it turned out many years ago, do not benefit ordinary citizens. A decrease in the incidence (by several percent) and the duration of acute respiratory infections (less than one day) compared with the control group that took the usual amount of ascorbic acid was found in only a few studies - among skiers and special forces who trained in the winter in the North. But there will not be much harm from megadoses of vitamin C, unless B12 hypovitaminosis or kidney stones, and even then only in a few of the most zealous and fanatical supporters of the body's ascorbation.
Myth 3 . Better shortage of vitamins than their enumeration.
To sort out the vitamins, you need to try very hard. Of course, there are exceptions, especially for the minerals and microelements that make up the majority of multivitamin complexes: those who eat a portion of cottage cheese every day do not need additional calcium intake, and those who work in the galvanic workshop do not need chromium, zinc and nickel. In some places in the water, soil and ultimately in the organisms of the people living there, there are excess amounts of fluorine, iron, selenium and other trace elements, and even lead, aluminum and other substances, the benefits of which are unknown, and the harm is beyond doubt. But the composition of multivitamin tablets is usually chosen so that in the vast majority of cases they cover the micronutrient deficiency in the average consumer and guarantee the impossibility of a serious overdose even with a daily and long-term intake in addition to the usual diet of several tablets.
Hypervitaminosis in most cases occurs with prolonged consumption of vitamins (and only fat-soluble ones that accumulate in the body) in doses exceeding the norm by orders of magnitude. Most often, and it is extremely rare, this is found in the practice of pediatricians: if you give a newborn a teaspoon of vitamin D per day instead of one big drop a week ... The rest is on the verge of jokes: for example, there’s a story about how all the housewives in the village bought under the guise of sunflower oil a solution of vitamin D stolen from the poultry farm. Or - they say, it happened like that - having read all sorts of nonsense about the benefits of carotenoids that “prevent cancer, " people started drinking carrot juice in liters per day, and some of this didn’t just turn yellow, but drank to death. It is impossible to absorb more than the maximum of vitamins determined by nature through the gastrointestinal tract with a single dose: at each stage of absorption into the intestinal epithelium, transmission to the blood, and from it to the tissues and cells, transport proteins and receptors on the cell surface are required, the number of which is strictly limited. But just in case, many companies pack vitamins in jars with “child-resistant” lids - so that the baby does not gobble up his mother’s three-month norm at a time.
III. Side effects
Myth 1 . There is an allergy from vitamins.
An allergy can develop to some drug that you have taken before and part of the molecule in structure is similar to one of the vitamins. But in this case, an allergic reaction can occur only with intramuscular or intravenous administration of this vitamin, and not after taking one tablet after a meal. Dyestuffs, fillers, and flavoring agents can sometimes cause allergies.
In this case, it is recommended to switch to vitamins of another company - perhaps they do not contain this particular component.
An apple a day keeps the doctor away?
The Russian analogue of this proverb - “a bow from seven ailments” - is also incorrect. Vegetables and fruits (raw!) Can serve as a more or less reliable source of vitamin C, folic acid (vitamin B 9 ) and carotene. To get the daily intake of vitamin C, you need to drink 3-4 liters of apple juice - from very fresh apples or canned, which contains about as many vitamins as indicated on the package. Leafy vegetables lose about half of vitamin C a day after harvest, peeled vegetables and fruits after several months of storage. The same thing happens with other vitamins and their sources. Most vitamins decompose when heated and exposed to ultraviolet radiation - do not keep a bottle of vegetable oil on the windowsill so that the vitamin E added to it does not break down. And when boiling, and even more so when frying, many vitamins decompose with each passing minute. And if you read the phrase “100 g of buckwheat contains ...” or “100 g of veal contains ...”, you were deceived at least twice. Firstly, this amount of vitamin is contained in the raw product, and not in the finished dish. Secondly, kilometer tables wander from one reference book to another for at least half a century, and during this time, the content of vitamins and other micronutrients in new, more productive and high-calorie plant varieties and in pork, beef and chicken grown by them decreased on average by half. True, many products have recently been fortified, but in general it is impossible to get enough vitamins from food.
Myth 2 . With the constant intake of vitamins, addiction to them develops.
Addiction to air, water, and fats, proteins and carbohydrates does not scare anyone. You will not get more than the amount for which the mechanisms of assimilation of vitamins are calculated - if you do not take doses for several months or even years, orders of magnitude more than necessary. And the so-called withdrawal syndrome is not typical for vitamins: after stopping their intake, the body simply returns to a state of hypovitaminosis.
Myth 3 . People who do not take vitamins feel great.
Yes - about the same way a tree growing on a rock or in a swamp feels great. Symptoms of moderate polyhypovitaminosis such as general weakness and lethargy are difficult to notice. It is also difficult to guess that dry skin and brittle hair should be treated not with creams and shampoos, but with vitamin A and stewed carrots, that sleep disturbances, irritability or seborrheic dermatitis and acne are not signs of neurosis or hormonal imbalance, but a lack of vitamins of the group B. Severe hypo- and vitamin deficiencies are most often secondary, caused by some disease in which the normal absorption of vitamins is impaired. (And vice versa: gastritis and anemia - a violation of the hematopoietic function, visible to the naked eye due to cyanosis of the lips - can be both a consequence and a cause of B12 hypovitaminosis and / or iron deficiency.) And the connection between hypovitaminosis and increased morbidity, up to a higher frequency of fractures with a lack vitamin D and calcium, or an increased incidence of prostate cancer with a lack of vitamin E and selenium, is noticeable only in a statistical analysis of large samples - thousands and even hundreds of thousands of people, and often when observed for several years.
Myth 4 . Vitamins and mineral elements interfere with the assimilation of each other.
Especially active is this point of view advocated by manufacturers and sellers of various vitamin-mineral complexes for separate administration. And they confirm the experimental data in which one of the antagonists was ingested in the usual amount, and the other in ten times large doses (we mentioned B12 hypovitaminosis as a result of the entrainment with ascorbic acid). Opinions of experts on the appropriateness of dividing the usual daily dose of vitamins and minerals by 2-3 tablets differ exactly the opposite.
Myth 5 . "These" vitamins are better than "Tech."
Usually multivitamin preparations contain at least 11 out of 13 vitamins known to science and about the same amount of mineral elements, each from 50 to 150% of the daily norm: the components, the lack of which is extremely rare, are fewer, and substances that are especially useful for all or individual population groups - just in case more. The norms in different countries vary, including depending on the composition of traditional nutrition, but not by much, so you can not pay attention to who established this norm: the American FDA, the WHO European Bureau or the USSR People's Commissariat of Health. В препаратах одной и той же фирмы, специально разработанных для беременных и кормящих женщин, пожилых людей, спортсменов, курильщиков и т. д., количество отдельных веществ может различаться в несколько раз. Для детей, от грудничков до подростков, тоже подбирают оптимальные дозировки. В остальном, как говорили когда-то в рекламном ролике, — все одинаковые! А вот если на упаковке «уникальной натуральной пищевой добавки из экологически чистого сырья» не указан процент от рекомендуемой нормы или вообще не написано, сколько милли- и микрограммов или международных единиц (МЕ) содержит одна порция, — это повод задуматься.
Миф 6 . Самая новая легенда.
Год назад СМИ всего мира облетела новость: шведские ученые доказали, что витаминные добавки убивают людей! Прием антиоксидантов в среднем увеличивает коэффициент смертности на 5%!! Отдельно витамин Е — на 4%, бета-каротин — на 7%, витамин А — на 16%!!! А то и больше — наверняка многие данные о вреде витаминов остаются неопубликованными!
Перепутать причину и следствие при формальном подходе к математическому анализу данных очень просто, и результаты этого исследования вызвали волну критики. Из уравнений регрессии и корреляций, полученных авторами сенсационного исследования (Bjelakovic et al., JAMA, 2007), можно сделать прямо противоположный и более правдоподобный вывод: больше общеукрепляющих средств принимают те пожилые люди, которые хуже себя чувствуют, больше болеют и, соответственно, скорее умирают. Но очередная легенда наверняка будет гулять по СМИ и общественному сознанию так же долго, как и другие мифы о витаминах.The article was published in the journal Popular Mechanics (No. 3, March 2008).