Retinol: dokazannaya polza i chego realistichno zhdat
Retinol — preformirovannaya, biologicheski dostupnaya forma vitamina A, kotoraya soderzhitsya v produktakh zhivotnogo proiskhozhdeniya i v bolshinstve dobavok. On otlichaetsya ot karotinoidov (naprimer, beta-karotina) v rasteniyakh, kotorye nuzhno preobrazovat v retinol v organizme. Vitamin A klassifitsiruyetsya kak nezamenimy zhirorastvorimyy mikroelement.
Osnovnye dokazannye preimushchestva
Funktsiya zreniya
Rol retinola v zrenii — nailuchshe dokumentirovannaya iz vsekh ego funktsiy. On neobkhodim dlya sinteza rodopsina v palochkakh setchatki. Defitsit vitamina A — vedushchaya predotvratimaaya prichina detskoy slepoty v mire.
Funktsiya immuniteta
Vitamin A reguliruet differentsirovku immunnykh kletok, vklyuchaya T-limfotsity, NK-kletki i makrofagi. Semba i dr. (2004) prishli k vyvodu, chto dobavki vitamina A znachitelno snizhaet obshchuyu smertnost u detey s defitsitom vitamina A (Semba et al., 2004).
Obnovlenie kozhi
Retinol neobkhodim dlya normal'noy proliferatsii i differentsiatsii epitelialnykh kletok, vklyuchaya keratinotsity kozhi. Topicheskiye retinoidy (proizvodnye vitamina A) imeyut obshirnoye klinicheskoye dokazatelstvo dlya terapii akne i fotostareniia.
Vtorostepennyye i voskhodyashchiye effekty
Metabolizm kostey
Vitamin A vzaimodeystvuet s vitaminom D v signalizatsii osteoblastov. Kak defitsit, tak i izbytok svyazany s izmeneniyami plotnosti kostey. Khronicheskiy izbytok vitamina A mozhet snizhat plotnost kostey, vmeshivayas v vozdeystvie vitamina D.
Reproduktivnoe zdorovye
U vitamina A est dokumentirovannye roli v spermatogeneze i razvitii ploda. Vo vremya beremennosti dostatochnoe potrebleniye kritichesky vazhno, no bezopasnyy verkhny predel nizhe, chem u neberemennych.
Gde dokazatelstv malo
Utverzhdeniya o tom, chto dobavki retinola u khorosho pitayushchikhsya vzroslykh obespechivaet antivorastnye effekty kozhi, sopostavimye s topicheskimi retinoidami, ne podtverzhdeny dokazatelstvami.
Kto poluchaet naibolshuyu vygodu
- Lyudi s nizkim dietarnym potrebleniyem vitamina A
- Vegetariantsy i vegany, u kotorykh potrebleniye vitamina A polnostyu zavisit ot konversii beta-karotina
- Lyudi s malabsorbtsiey zhirov
- Beremennyye — s tshchatelnym soblyudenyem verkhnego bezopasnogo predela
Bezopasnyy verkhnyy predel
Vitamin A — zhirorastvorimyy i nakaplivaletsya v pecheni. Hronicheskoe izbytochnoe potreblenie mozhet privesti k gipervitaminozu A. Dopustimy verkhniy uroven potrebleniya dlya vzroslykh v Yevrope sostavlyaet 3000 mkg RAE v den.
Takiye produkty, kak BIOTECHUSA Active Women 60tab i SELF Beta carotene 60caps — dostupnye na maxfit.ee. Smotrite kategoriyu vitaminnykh kompleksov i otdelnykh vitaminov.
Chasto zadavaemye voprosy
Eto retinol i vitamin A — odno i to zhe?
Retinol — preformirovannaya, gotovaya k ispolzovaniyu forma vitamina A iz produktov zhivotnogo proiskhozhdeniya. Beta-karotin iz rasteniy — provitamin A, kotoryy organizm preobrazuet v retinol. Effektivnost preobrazovaniya variabilna.
Mozhno li poluchit slishkom mnogo vitamina A?
Da — vitamin A zhirorastvorimyy i mozhet nakaplyvatsya do toksichnykh urovney. Sokhranjayte dazy na urovne ili nizhe rekomendovannogo verkhnego predela (3000 mkg RAE/den dlya vzroslykh v Yevrope).
Nuzhdayutsya li sportsmeny v bolshem kolichestve vitamina A?
Net ubeditel'nykh dokazatelstv togo, chto sportivnye trenirovki znachitelno uvelichivayut potrebnost v vitamine A. Obespechenie adekvatnosti pitaniya vazh'no, no megadozy ne obosnovany.
Ssylki
Sommer, A., & Vyas, K. S. (2012). A global clinical view on vitamin A and carotenoids. American Journal of Clinical Nutrition, 96(5), 1204S-1206S. https://pubmed.ncbi.nlm.nih.gov/23053560/
Semba, R. D. (2004). Vitamin A, immunity, and infection. Clinical Infectious Diseases, 19(3), 489-499.
