Статьи

Vitamin A

  1. 1. What is vitamin A for?
  2. 2. What affects its absorption
  3. 3. How much vitamin must be taken every day
  4. 4. Food as a source of vitamin A
  5. Conclusion

Hello dear readers Hello dear readers!

To say that modern science and medicine knows everything about vitamins is impossible, but something we still know. Vitamin A is the vitamin of new life. Without it, normal cell division, twilight vision and protection from infections are impossible. Only it is not one substance, but the whole family.

1. What is vitamin A for?

At the time of its discovery, vitamin A got the name anti-infection . The fact is that with its lack of food, the skin and mucous membranes suffer, especially in the respiratory tract. When the mucous membranes do not perform their functions properly, the infection can freely enter the human body and cause disease.

Modern cosmetology successfully uses retinoic acid cream to combat wrinkles and prevent stretch marks . Only pregnant women and women planning conception cannot use this substance - the risk of teratogenic action is high. And not due to the fact that retinoic acid is absorbed from the cream - it almost does not enter the blood. The risk comes from the fact that its external use has a significant impact on the behavior of vitamin A, which is inside us.

An important aspect of vitamin A is providing twilight vision. A special substance, the pigment of the retina, is involved in the conversion of light energy into a nerve impulse. It is through this chemical reaction that we can see. With a lack of vitamin A, so-called night-blindness develops - a person cannot see in dim light.

Vitamin A is important for normal functioning of the thyroid gland and for blood formation, bone formation, of teeth It also participates in the regulation of inflammatory reactions.

It must be said that vitamin A deficiency is a rarity in developed countries, which, alas, cannot be said of developing ones. Where people have free access to animal products, fatty foods and food additives, deficiency symptoms develop only in exceptional cases.

At risk are people:

  • Having some genetic disorders (for example, cystic fibrosis).
  • With impaired fat metabolism.
  • Having diseases of the liver, pancreas, intestines.
  • Consumers alcohol .
  • Smokers .
  • Vegans.

Why is that? Vitamin A is represented by two groups of substances:

  • Retinoids that are found in animal products.
  • Carotenoids - bright orange pigments from plant foods.

Carotenoids - bright orange pigments from plant foods

In any case, these are fat soluble substances. That is, when a person loses the ability to adequately absorb fats , it automatically faces the problem of the deficiency of fat-soluble vitamins.

2. What affects its absorption

Alcohol, nicotine, and some other toxins or drugs alter our ability to absorb vitamins. By the way, vitamins and minerals also affect the absorption and metabolism of each other. Disruption of the balance with food or supplements of iron, selenium, vitamin E, D and K can greatly affect the metabolism of retinol, and not for the better.

For example, taking vitamin A against the background of vitamin D deficiency leads to aggravation of signs of calciferol deficiency - brittle bones.

Vegans fall into the risk group - their diet does not contain retinol at all - the active form of vitamin A. Carotenoids are only precursors of vitamin A in our body. In order to create one molecule of active retinol, we need to use from 12 to 24 (!) Molecules of food carotene. This is really a lot of food! And do not forget that it should be fatty enough that carotenoids can be properly digested. And it is very many calories ! And, of course, the person himself must be able to assimilate them.

However, to abandon the yellow, orange, green and red vegetables is not worth it. On the contrary, they need to be included daily in your diet. Especially pregnant women and those planning to conceive. Firstly, they are very useful in their own right, and modern science is far from fully revealing their potential for health. Secondly, vitamin A directly affects the ability of women to conceive and make a healthy child. And thirdly, some forms of carotenoids themselves, in their original form, have a beneficial effect on our health. For example, grapefruit and tomatoes contain lycopene, which has anti-cancer activity. It is also important for good vision, as well as prevention of cardiovascular diseases.

3. How much vitamin must be taken every day

Retinol, in excess is toxic to our body. The first signs of overdose are headache, fatigue, poor appetite, nausea, dryness and flaking of the skin ... Chronic overdose leads to the development of osteoporosis , damage to the liver, and subsequently to death.

Fortunately, in order to exceed your rate, you need to consume a large amount of retinol daily. For example, every day there is a liver of animal inhabitants of the north and cold seas, or to take a synthetic vitamin in an amount greater than the recommended.

Carotenoids are presumably non-toxic. Our body is able to convert carotenoids to retinol as needed. In excess, it will not do that. Yes, and the person who uses carotene more than necessary, very soon change the skin color to yellow and, most likely, will make changes in your diet.

The recommended intake of vitamin A is as follows:

  • Children from 1 to 3 years: 300 µg RAE (1000 IU²)
  • Children from 4 to 8 years: 400 µg RAE (1333 IU)
  • Children from 9 to 13 years: 600 µg RAE (2000 IU)
  • Men 14 years and older: 900 µg RAE (3000 IU)
  • Women 14 years and older: 700 µg RAE (2333 IU)

Expected average requirements (from 2000) for vitamin A consumption by pregnant and nursing:

  • Pregnant women under 18: 750 µg RAE (2500 IU)
  • Pregnant women 19 years and older: 770 µg RAE (2567 IU)
  • Nursing 18 years or younger: 1200 µg RAE (4000 IU)
  • Nursing 19 years and older: 1300 µg RAE (4333 IU)

Note! Pregnant women and women planning conception are strongly advised not to take vitamin A supplements! []

_______________________________________________

  1. RAE - the equivalent of active retinol
  2. ME - international units

1 µg of retinol = 1 RAE or 1 RE (equivalent of retinol), and 1 RE = 6 µg of beta-carotene or 12 µg of alpha-carotene or beta-cryptoxanthin.

In addition, 1 RAE is equal to 12 μg of beta-carotene or 24 μg of alpha-carotene or beta-cryptoxanthin. 1 IU is 0.3 μg of retinol, 0.6 μg of beta-carotene, or 1.2 μg of alpha-carotene or beta-cryptoxanthin.

Alas, in the majority of vitamins for pregnant women in the domestic market contains 100% of vitamin A from the daily requirement or more. And not always indicated the substance in the form of which this vitamin is part of the pill.

The maximum doses of vitamin that, with regular use, with a high probability will lead to an overdose are as follows:

  • Children 3 years and under, 600 mcg (2000 IU) retinol per day.
  • Children 4-8 years old, 900 mcg (3000 IU) of retinol per day.
  • Children 9-14 years old, 1700 mcg (5.666 IU) of retinol per day.
  • Adolescents 14-18 years old, 2800 mcg (9.333 IU) of retinol per day.
  • Adults 19 years and older, 3,000 mcg (10,000 IU) of retinol per day.
  • Pregnant and lactating women, 18 years or younger, 2800 mcg (9.333 IU) of retinol per day.
  • Pregnant and lactating women 19 years and older, 3000 mcg (10,000 IU) of retinol per day.

Some people, due to their metabolic peculiarities, are at risk of an overdose of vitamin A. They should not take it in the form of supplements without medical advice. These people include:

  • Pregnant
  • Smokers.
  • Systematically use alcohol and other toxins.
  • Having problems with the thyroid gland.
  • Taking some drugs and supplements.

The main problem is that excess fat-soluble vitamins cannot be quickly removed from the body and accumulate. The toxic effect is multiplied and maintained for a sufficiently long time after the cessation of their reception.

4. Food as a source of vitamin A

What are the best food sources? Let's look at the table.

By the way, vitamin A is quite stable when cooked. The only exception is retinol-palmitate enriched beverages. They can not be stored in the light - only in a darkened or opaque container.

Product Source

Serving size

KcalVitamin A (µg RAE)% of the daily requirementNutritional densityGrade

Batat 1 stack. 180 1921.8 214 21.4 excellent Carrots * 1 stack. 50 1019.07 113 40.7 excellent Spinach 1 stack. 41.4 943.29 105 45.6 excellent Calais 1 stack. 36.4 885.36 98 48.6 Excellent Mustard 1 stack. 36.4 865.9 96 47.6 Excellent Kale 1 stack. 62.7 722 80 23 excellent Beet leaves 1 stack. 38.9 551.09 61 28.3 excellent Turnip 1 stack. 28.8 549 61 38.1 excellent Swiss chard 1 stack. 35,535.85 60 30.6 excellent Pumpkin 1 stack. 75.8 535.36 59 14.1 excellent Romaine salad 2 stack. 16,409.37 45 51.2 excellent Bock Choi 1 stack. 20.4 361.16 40 35.4 Excellent Musk Melon 1 stack. 54.4 270.56 30 9.9 excellent Bulgarian pepper 1 stack. 28.5 144.03 16 10.1 excellent Parsley 1/2 stack. 10.9 128.04 14 23.4 excellent Broccoli 1 stack. 54.6 120.74 13 4.4 very good Asparagus 1 stack. 39.6 90.54 10 4.6 very good Laminaria 1 tbsp 10.8 81.05 9 14.9 very good Chili 2 tsp 15.2 80.05 9 10.5 very good Tomatoes 1 stack. 32.4 74.97 8 4.6 very good Basil 1/2 stack. 4.9 55.91 6 22.9 very good Papaya 1 pc 118.7 131.1 15 2.2 good Shrimps 120 g 134.9 102.06 11 1.5 good Eggs 1 pc 77.5 74.5 8 1.9 good Brussels sprouts 1 stack. 56.2 60.45 7 2.2 good Grapefruit half 41 59.33 7 2.9 good Cow's milk (enriched) 120 g 74.4 56.12 6 1.5 good Green beans 1 stack. 43.8 43.75 5 2 good Watermelon 1 stack. 45.6 43.24 5 1.9 good Leeks 1 stack. 32.2 42.22 5 2.6 good Apricot 1 pc 16.8 33.7 4 4 good Coriander 1/2 stack. 1.8 26.99 3 29.3 good Celery 1 stack. 16.2 22.67 3 2.8 good

* The content of beta-carotene in carrots varies greatly from grade to grade.

The table focuses on sources of beta-carotene. And that's why:

  • Beta-carotene is most beneficial for the synthesis of retinol.
  • This substance is safe and does not carry the risk of overdose.
  • Sources of beta-carotene contain other important carotenoids and phytonutrients.

There is another type of food, this time of animal origin, which is an inexhaustible source of vitamin A in active form. There is another type of food, this time of animal origin, which is an inexhaustible source of vitamin A in active form This is the liver of birds and animals:

Product - source Size Kcal Vitamin A (µg RAE)% of the daily requirement Nutritional density Assessment Pork liver 30 g 40 1818.6 202 92 Excellent Beef liver 30 g 40 1419.6 157 71.7 Excellent Chicken liver 30 g 35 930.6 103 46.8 Excellent

If you include these products in your diet 2-3 times a week in the form of pâté, stews, small steaks or meatballs, you can be completely sure that your body is adequately provided with vitamin A and not only. After all, the liver is rich in iron, zinc, B vitamins, folic acid (80-85 mg in 30 grams), phosphorus and selenium. A rare product that boasts such a rich set of micronutrients.

Conclusion

Vitamin A is essential for the preservation of beauty and health. In developed countries, where all possible products are available to people - sources of this vitamin, deficiency is extremely rare. On hand there is always the right food and synthetic vitamin supplements. The chance of an overdose will be much higher.

The safest and most beneficial way for a person to get his / her vitamin A standard is to eat foods that are rich in beta-carotene and sometimes include liver in your diet. Carotenoids and retinoids are absorbed only in the presence of fat.

Sincerely, Elena Dyachenko

Your personal consultant in matters of harmony

1. What is vitamin A for?
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