L-tirozin: svezhistshiye issledovaniya i dokazatel'stva
L-tirozin - eto uslovno nezamenimaya aminokislota, kotoraya sluzhit predshestvennikom dopamina, noradrenalina, adrenalina i gormonov shchitovidnoy zhelezy. Interes k nemu kak k dobavke dostig pika v kontse 1990-kh godov na osnove finansirovannykh voyennymi issledovaniy kognitivnoy produktivnosti v usloviyakh stressa. Dva desyatiletiya spustya dokazatel'naya baza vyrosla - i izmenila napravleniye vazhnymi sposobami.
Chto pokazyvayut nedavnie ispytaniya
Naibole vosproizvodimym nablyudeniom dlya l-tirozina ostayotsya ego sposobnost' oslabyat' kognitivny upad v ostro trebovatel'nykh usloviyakh. Dvojnoe slepoe perekrestnoye RKI obnaruzhilo, chto razovaya doza tirozina uluchshila rabotu operativnoy pamyati pri trebovatel'nom kognitivnom zadanii po sravneniyu s platsebo (Jongkees et al., 2015). Effekt byl naisilneyshim u uchastnikov v usloviyakh stressa mul'tizadachnosti - real'nyy stsenary, neposredstvenno relevantnyy dlya sportsmenov i smennych rabochikh.
Sistematicheskiy obzor i metaanaliz chetyrnadtsati kontroliruyemykh ispytaniy prishol k vyvodu, chto dobavka tirozina sistematicheski uluchshala kognitivnuyu gibkost' i operativnuyu pamyat' v usloviyakh ostrogo stressa ili utomleniya, s razmerami effektov v diapazone malykh-srednikh (Jongkees et al., 2015). Kriticheski vazhno, chto tot zhe obzor ne obnaruzhil znachimoy pol'zy pri nestressovom bazovom sostoyanii - razlichiye, kotoroe menyayet, kak praktiki dolzhny pozitsionirovat' tirozin.
Chto kasayetsya shchitovidnoy zhelezy, tirozin teoreticheski vazhen, potomu chto yodirovannyye ostatki tirozina obrazuyut T3 i T4. Odnako kontroliruyemyye ispytaniya u lyudey bez defitsita shchitovidnoy zhelezy ne pokazali klinicheski znachimykh izmeneniy v urovnyakh gormonov shchitovidnoy zhelezy ot dobavki, i tekushchiye svidetel'stva ne podderzhivayut tirozin kak usiliteli shchitovidnoy zhelezy u eyutiroidnykh lits.
Sdvigi v konsensuse
Obshchaya diskussiya udalila ot vzglyada na l-tirozin kak na universal'nyy kognitivnyy usiliteli. Konsensus teper' bolee nyuansirovan: tirozin navernyaka yavlyayetsya dobavkoy popolneniya - on rabotayet, vosstavlavlivaya dostupnost' katekholaminov, kotorye istoshchayutsya vo vremya ostrogo stressa, lishneniya sna ili vozdeystviya ekstremalnogo kholoda. Eto oznachayet:
- Lyudi s vysokoy kognitivnoy nagruzkoy, lishennye sna ili v kholodnoy srede mogut ispytyvat' pol'zu
- Lyudi v komfortnom, otdokhivshem bazovom sostoyanii ne vroyatno zamechat znachimye effekty
- Net svidetel'stv pol'zy dlya khronicheskogo upravleniya stressom ili stabilizatsii nastroyeniya
Otkrytye voprosy
Neskol'ko oblastey ostayutsya nereshonnymi. Optimal'noye vrema otnositel'no stressora ostayotsya diskussionnym - bol'shinstvo protokolov ispol'zovalo dozy za 60-120 minut do trebovatel'noy zadachi, no farmakokinetika predlagayet, chto pikovoe plasmennoye okno mozhet byt' koroche. Minimal'naya effektivnaya doza u lyudey takzhe ne ustanovlena tvyordo, i individual'naya variativnost' otveta (kotoraya kazhetsya znachitel'noy) plokho kharakterizovana. Dolgosrochnye issledovaniya dobavok svykhe vos'mi nedel' v znachitel'noy mere otsutstvuyut.
Prakticheskie vyvody
Glavnoye soobshcheniye iz obnovleniya issledovaniy yasnoye: tirozin luchshe vsego ispol'zovat' situatsionno, a ne khronicheski. Prinimayte ego pered ozhidayemym stressorom - vazhnyy ekzamen, tyazhelyy trenirovochnyy sezon, nochnaya smena - a ne kak yezhednevnuyu universal'nuyu dobavku. MST L-Tyrosine 500mg 90caps i OstroVit Tyrosine 210g Naturaalne oba dostupny na maxfit.ee i predstavlyayut chistyye, odnokkomponentnyye formaty, khorosho podkhodyashchiye dlya situatsionnogo ispol'zovaniya. OstroVit Tyrosine 210g Apelsin predlagayet varianty aromatizovannogo poroshka dlya tekh, kto predpochitayet smeshivat' ego v pred-trenirovochnyy napitok.
Ne kombiniruyete tirozin s ingibitorami MAO ili preparatami dlya shchitovidnoy zhelezy bez meditsinskogo nablyudeniya. Dlya lyudey s fenilketonuriey (PKU) dobavka tirozina trebuet rukovodstva vracha.
Zaklyucheniye
Issledovaniya l-tirozina sformiroval soglasovannoye kartinu: dobavka dayet nadezhnyye, khotya i skromnyye kognitivnyye preimushchestva, spetsificheski v usloviyakh ostrogo istoshcheniya. Eto ne yezhednevnyy nootropik, ne usiliteli shchitovidnoy zhelezy u zdorovykh lyudey i ne stabilizator nastroyeniya. Ispol'zovanny pravil'no - pered trebovatel'nymi situatsiyami, v kotorykh veroyatno istoshcheniye katekholaminov, - on zarabatyvayet svoyo mesto v umnoy instrumentarii dobavok.
Chasto zadavayemyye voprosy
Stoit li prinimat' l-tirozin kazhdyy den'?
Tekushchiye svidetel'stva ne podderzhivayut yezhednevnoye primeneniye dlya zdorovykh lits v normal'nykh usloviyakh. Nailuchshe podtverzhd yonnnoye primeneniye - situatsionnoye: prinyatoye pered periodami ostrogo stressa, lishneniya sna ili ekstremalnykh kognitivnykh trebovaniy. Khronicheskoye yezhednevnoye primeneniye ne imeet dokazannoy dopolnitel'noy pol'zy po sravneniyu s redkym.
Mozhet li l-tirozin pomoch' s zdorov'yem shchitovidnoy zhelezy?
L-tirozin yavlyayetsya stroitel'nym blokom dlya gormonov shchitovidnoy zhelezy, no kontroliruyemyye ispytaniya ne pokazali, chto dobavka znachimo povyshayet T3 ili T4 u lyudey s normal'noy funktsiyey shchitovidnoy zhelezy. Yesli u vas podtverzhden'nyy sostoyaniye shchitovidnoy zhelezy, obsudite dobavku so svoim vrachom.
Skol'ko l-tirozina mne sleduyet prinimat'?
RKI, demonstriruyushchiye kognitivnyye preimushchestva, kak pravilo, ispol'zovaly dozy v diapazone 100-150 mg na kilogramm massy tela (Jongkees et al., 2015), no prakticheskie dozy v issledovaniyakh dobavok znachitel'no vary. Tipichnaya porciya dobavki 500-2000 mg, prinyataya za 60-90 minut do trebovatel'noy zadachi, nakhoditsya v issleedovannom diapazone. Sleduyete etiketke vybranogo produkta.
Ssylki
Jongkees, B. J., Hommel, B., Kuhn, S., & Colzato, L. S. (2015). Effect of tyrosine supplementation on clinical and healthy populations under stress and deprivation conditions: a systematic review. Journal of Psychiatric Research, 70, 50-57.
Young, S. N. (2007). L-tyrosine to alleviate the effects of stress? Journal of Psychiatry & Neuroscience, 32(3), 224.
Oliver, J. M., Anzalone, A. J., & Turner, S. M. (2019). Protection before impact: the potential neuroprotective role of nutritional supplementation in sports-related head trauma. Sports Medicine, 49(Suppl 1), 35-42.
