Vitamin A – Retinol
Only found as such in foods of animal origin, although the plant is found as provitamin A, in the form of carotenoids. The various carotenoids are converted in the human body and stored in the liver and fatty tissue of the skin, making it possible to survive long periods without their input.
Its main task is to protect the skin and eyes. It also participates in the development of enzymes in the liver and adrenal sex hormones.
The consumption of foods rich in vitamin A is recommended for people prone to respiratory infections, eye problems or skin dry and flaky.
Fat-Soluble Vitamins
Fat-soluble vitamins are vitamins A, D, E and K. To some extent, this vitamin is different from the water-soluble vitamins. This vitamin is contained in fat and oily part of food. These vitamins are digested by the bile only because it is not soluble in water. The following section provides a detailed description of each vitamin type.
Vitamin A
It is difficult to determine the number requirement of vitamin A. This vitamin is produced from two different compounds that are converted in the body into vitamin A. In animal food sources, available in the form of retinol; in vegetable food sources are in the form of beta-carotene, which is less efficient than retinol for production of vitamin A. make This is the recommended amount of vitamin A given in the form of retinol equivalent, RE. The recommended amount of vitamin A is 1000 micro-grams per day for males and RE 800 micro-grams for women. Continue reading
Vitamin D and HIV
Despite everything we know about vitamin D, anyone can bet that nothing will surprise us about this vitamin?
I certainly do not. Reviewing some of the latest published studies on vitamin D one caught my attention appeared in the Journal of Infectious Diseases in October 2009. The study was conducted in Tanzania, a country particularly affected by the HIV epidemic, with 884 infected pregnant women.
And the results were quite significant:
- 61% higher mortality during follow-up in children born to mothers with low vitamin D.
- 50% more cases of HIV measured in the sixth week of birth in children born to mothers with low vitamin D.
- 49% fetal mortality or HIV infection detected at birth in mothers with low vitamin D.
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Molecule of Vitamin A
In the body, it exists as Retinol from retinal, Retinoic acid and retinyl phosphate. These molecules are altered by oxygen in the air, changes accelerated by light and heat.
Foods of animal origin (meat, dairy products and especially liver) contain retinol and retinyl esters, whereas plants contain predominantly carotenes which are precursors of retinol. One molecule of beta-carotene, by hydrolysis of the 15-15 ‘under the influence of carotenoid monooxygenase (??-carotene 15,15′ monooxygenase), gives two molecules of vitamin A. For cons, the two other Carotenes (alpha and gamma) give birth to only one molecule of vitamin A.
The need for vitamin A are estimated at about 5 000 IU per day. An international unit of vitamin A equals 0.3 mg of retinol. Retinol is considered the basic unit, retinol-equivalent, which compares the vitamin activity of various derivatives of vitamin A. The most useful form of vitamin A is retinol, although it can also be found in the form of retinal or retinoic acid. Retinol is a hydrophobic molecule synthesized from isoprene. Vitamin A is involved in bone growth and synthesis of pigments of the eye. Retinol is sometimes used to treat severe acne.
Vitamin A
It is found in cheese, eggs, butter, margarine, giblets, fish oils and vegetables. Function can increase resistance to certain diseases, important for eye function and cell membranes.
Employment and dosage in cases of colds and flu, acne, heavy menstruation, osteoarthritis, poor growth and flaky skin, take up to 4.5 mg per day. Hair loss may indicate an excess or a deficiency of vitamin A. For men, 700 mcg and 600 mcg for women is the recommended ideal dose.
Warning Pregnant or planning a pregnancy, do not take vitamin A unless under the supervision of a physician, avoid it if you suffer from headaches.
IMPORTANT NOTES
* Take supplements late in the evening, several hours after eating or taking other supplements. If you cause stomach irritation, take with meals.
* Do not exceed suggested dosage of supplements. Information on the dosage that appears on the packaging of supplements varies greatly, so make sure you read the packaging carefully, and if in doubt, consult a doctor or a physician specializing in nutrition.
* If taken in excess, water-soluble vitamins like B and C, are naturally eliminated, while fat-soluble vitamins like vitamins A, D, E and K, accumulate and cause tissue damage .
* The doses listed here are not suitable for children, unless otherwise indicated.
* Do not turn food supplements during the first 14 weeks of pregnancy, unless recommended by a doctor.
* In general, unless otherwise indicated, take a supplement for a month and, if it is beneficial. continue to take 5 days per week for another month. After this deadline stop eating and consult a doctor or a physician specializing in nutrition.