Multi oameni cred ca organismul poate utiliza doar 30 de grame de proteine odata. Dar imaginati-va ca mancati o friptura mare. Daca ati putea folosi doar 30 de grame odata, a doua zi ati avea friptura in toaleta. Dar asta nu se intampla. Asadar, unde merge friptura?
Proteinele ajuta la construirea muschilor mari - dar stiai deja asta; exista o limita a cantitatii de proteine care ajunge cu adevarat in tesutul muscular? Nu este un proces 100% eficient, deoarece constructia musculara este lenta si consuma multa energie. Cercetari de aceeasi autori au estimat ca dintr-o doza de 20 de grame de proteine din zer, doar 2 grame ajung direct ca proteina in tesutul muscular.
Noul studiu: Limita superioara de utilizare a proteinelor?
Dr. Jorn Trommelen a dorit sa determine daca exista o limita a cantitatii de proteine pe care organismul o poate absorbi si utiliza pentru sinteza proteinelor musculare (MPS) sau procesul de a introduce a aminoacizilor in tesutul muscular. El a efectuat teste pe 12 barbati tineri sanatosi care au consumat diferite cantitati dintr-o proteina speciala din lapte. Aceasta proteina continea aminoacizi marcati cu izotopi, astfel incat cercetatorii sa ii poata urmari prin organism si sa vada unde ajung.
Dr. Jorn avea cateva banuieli inainte de inceperea studiului: "Se crede in general ca doar 20-40 de grame de proteine sunt folosite eficient pentru construirea muschilor, aminoacizii in exces fiind irositi ca si combustibil (oxidare). Sunt sceptic si emit ipoteza ca beneficiul cantitatilor mai mari de proteine devine evident doar atunci cand se tine cont de timpul prelungit de digestie necesar unei doze mari."
Deci, ce s-a intamplat de fapt? Dupa antrenamente cu greutati, subiectii au primit fie 25 de grame de proteina, 100 de grame de proteina, fie un placebo. Ei au efectuat o singura sesiune de exercitii de rezistenta pentru tot corpul pana la epuizare. Apoi, au primit patru perfuzii cu izotopi stabili de aminoacizi folosind proteina din lapte marcata intrinsec. Li s-au luat o serie de probe de sange si biopsii musculare timp de 12 ore.
Rezultatul: Fara limita superioara pentru utilizarea proteinelor?
Conform acestui studiu, nu pare sa existe o limita superioara a capacitatii organismului de a absorbi proteine si de a sintetiza proteine musculare. Ceea ce inseamna ca organismul poate folosi mai multe proteine odata! Dar asteptati, sunt cateva detalii de acoperit.
Alte informatii importante:
- Acest studiu a implicat un antrenament intens pentru tot corpul si o doza unica de proteine, mai multe cercetari fiind necesare pentru a confirma rezultatele pe termen lung.
- Raspunsul anabolic la proteine scade odata cu varsta si in anumite stari patologice.
- Arderea aminoacizilor a fost minima, sugerand ca proteinele au fost folosite pentru reconstruirea de muschi.
- Sinteza proteinelor din tesutul conjunctiv muscular a crescut dupa consumul de 25 si 100 de grame de proteine.
Recomandari
Studiul ofera flexibilitate in distribuirea proteinelor pe parcursul zilei, dar nu inseamna ca trebuie sa consumati 100 de grame de trei ori pe zi.
Nu va pierdeti in detalii. Ideea principala este sa va asigurati ca respectati doza de proteina pe care o aveti alocata in fiecare zi. Cercetarile actuale arata in jur de 1,6 - 1,8 grame pe kilogram de greutate corporala si posibil aproape de 2 grame pe kilogram de greutate corporala daca reduceti mult caloriile (ca in timpul dietei de slabire). Daca sunteti cineva care trage de fiare la o greutate corporala de 90 de kilograme, asta inseamna cam 140-150 de grame de proteine pe zi ca pragul cel mai de jos si 180-200 de grame in partea de sus.
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