Proteine dupa antrenament - sunt necesare?

Exista multe intrebari privind nutritia dupa antrenamente. Si aceste intrebari se refera mai ales la suplimentele nutritive care ar trebui luate (sau nu) imediat dupa un antrenament. Daca te uiti online gasesti o groaza de informatii contradictorii (iar cand in joc intra si interesele producatorilor de suplimente nutritive, lucrurile se complica si mai mult). 

In acest articol o sa incercam sa facem putina lumina, folosind informatii bazate pe diferite studii de specialitate pentru ca tu sa poti decide daca merita sa investesti intr-o proteina si ce protocol de suplimentatie ti se potriveste cel mai bine.

De ce sa bei o proteina dupa antrenamente

Primul lucru de inteles este rolul suplimentarii cu proteine dupa antrenamente. Probabil ca multi dintre voi cei care cititi acest articol cumprati astfel de pudre si pastile de ani de zile, dar nu stiti exact de ce. Asa recomanda marii culturistii, asa recomanda antrenorii si...asa se face la sala!

Motivul #1: sinteza proteinelor musculare. Sinteza proteinelor musculare inseamna in termeni simplii crearea de nou tesut muscular. Acest proces este deja crescut dupa un antrenament, datorita tensiunii musculare provocate de greutati. Sinteza proteinelor musculare poate fi crescuta si mai mult dupa un antrenament prin administrarea de aminoacizi din proteine.

Sinteza a proteinelor musculare mai mare ► o absortie mai mare a proteinelor in muschi ► muschi mai mari

Motivul #2: cresterea nivelelor de insulina. Insulina este hormonul din corp responsabil cu depozitarea - adica impinge glucoza si aminoacizii in tesuturile musculare - si tot insulina este hormonul care inhiba cortizolul - in termeni practici inseamna ca reduce stresul muscular provocat de antrenamentele cu greutati si previne descompunerea tesutului muscular (cortizolul este catabolic, adica descompune muschii pentru energie). 

Intr-o singura fraza, proteinele consumate imediat dupa antrenament duc corpul dintr-o stare catabolica in una anabolica. Fac asta prin furnizarea de aminoacizi care cresc sinteza proteinelor si nivelele de insulina, si inhiba descompunerea tesutului muscular si cortizolul.

Ce proteine sunt mai bune?

In privinta tipului de proteine, cele lichide le intrec pe cele solide datorita ratei superioare de absortie. De aceea imediat dupa antrenament este mai util sa bei un shake proteic decat sa mananci o bucata de carne! Vrei ca actiunea anti-catabolica si anabolica a proteinelor sa inceapa imediat, pentru a preveni pierderea de tesut muscular si a initia repartiile celulelor musculare, care duc la cresteri musculare. 

Dintre proteinele lichide, cele din zer sunt cele mai bune datorita profilului aminoacizilor. 

Nota: Chiar daca proteina din soia apare in tabel, nu inseamna ca ar trebui sa fie una din primele optiuni. Unele studii sustin ca soia este toxica pentru oameni, cu exceptia produselor din soia fermentate, si poate chiar descreste forta musculara, scazand testosteronul si crescand cortizolul. Daca vrei o proteina vegetala o optiune mult mai buna este cea din mazare.

Aminoacizii cu lanturi ramificate (BCAA) din proteina din zer au grija ca nivelele de insulina sa creasca, iar nivelele ridicate de leucina cresc sinteza proteinelor. 

Acelasi efect se obtine si daca iei un supliment cu BCAA bogat in leucina. Intr-un studiu din 2008 publicat in "American Journal of Physiology Endocrinology and Metabolism" un grup de subiecti care s-a suplimentat cu 20 g aminoacizi esentiali imbogatiti cu leucina si 30 g carbohidrati la o ora dupa terminarea exercitiilor fizice a avut o crestere de 145% a sintezei proteinelor, comparativ cu 41% la subiectii care nu s-au suplimentat cu nimic. 

In privinta masei musculare suplimentarea cu aminoacizi esentiali si leucina este la fel de benefica precum suplimentarea cu proteina din zer, dar proteina din zer are si alte avantaje pentru sanatate (contine lactoferin, albumina si lactalbumina). Acestea sunt folosite in cantitati mari de anticorpii sistemului imunitar (IgA) si ajuta la formarea aminoacidului cisteina (dar si a altora) care in schimb sustine producerea unui foarte important antioxidant  - glutationul.

Beneficiile glutationului sunt:

• Imbunatatirea absortiei nutritientilor.
• Cresterea secretiei de serotonina si a functiilor cognitive.
• Inhibarea bacteriilor patogene (precum E.coli).
• Reducerea stresului oxidativ si neutralizarea toxinelor.
• Imbunatateste glicemia pe nemancate si sensibilitatea la insulina.
• Incurajeaza dezvoltarea bacteriilor benefice din intestine.
• Protejeaza impotriva tumorilor si reduce riscul de cancer.
• Reduce grasimea din ficat.
• Imbunatateste sanatatea oaselor.
• Creste rata metabolica bazala si oxidarea grasimilor.
• Scade riscul de boli cardiovasculare prin imbunatatirea tensiunii, profilului lipidic si functiilor vasculare. 
• Amelioreaza simptomele autismului si depresiei.
• Protejeaza de astm, eczeme si alergii alimentare.

In ciuda a ceea ce se crede, proteina din zer este mult mai putin probabil sa cauzeze sensibilitati. De aceea este si proteina care abunda in laptele matern, fiind mai usor digerata de oameni (spre deosebire de laptele de vaca care este bogat in cazeina).

Ce fel de proteina din zer este cea mai buna

Intrebi pe fata de la barul salii de forta unde mergi si iti va spune hidrolizat de zer. Intrebi pe cei care sustin consumul de "alimente adevarate" si iti spun sa iei lapte crud de la vaci crescute pe pasuni necalcate de piciorul omului! Pe cine asculti?

Cel mai bine e sa faci ce ti se potriveste tie. Daca te antrenezi doar ca sa fii sanatos alegi lapte crud (si alte lactate) de cea mai buna calitate. Daca vrei masa musculara alegi hidrolizatul sau un supliment cu BCAA bogat in leucina. 

Daca le vrei pe ambele si nici nu vrei sa dai o groaza de bani, alege concentrate sau izolate din zer, de cea mai buna calitate, netratate termic (tratamentul termic denatureaza proteinele). Pudrele de calitate, netratate termic, contin in continuare elementele care intaresc sistemul imunitar si in acelasi timp cresc la maxim sinteza proteinelor. Ca si eficienta a costului, concentratul proteic din zer este cel mai avantajos (cel mai bun raport pret/calitate). 

Dar comparatia concentrat/izolat tine mai ales de preferintele personale. Concentratul din zer este mai accesibil si contine mai multe substante benefice sanatatii generale. Izolatul din zer are un impact ceva mai mare asupra cresterii sintezei proteinelor si contine mai putina lactoza si carbohidrati.

Cei care au ca principal obiectiv arderea grasimilor ar trebui sa aleaga izolatul proteic din zer. Astfel de pudre proteice cresc de unele singure sinteza proteinelor si reduc catabolismul, nefiind nevoie de carbohidrati si o stimulare excesiva a insulinei. 

Cei care vor masa musculara si sa sustina antrenamentele solicitante (in special cele de mare intensitate care golesc rezervele de glicogen) ar trebui sa favorizeze concentratele proteice din zer (eventual cu ceva carbohidrati adaugati, in functie de scop si nivelele de grasime).

Exista o doza optima?

Raspunsul simplu este "da", dar doza variaza in functie de  particularitatile individuale. Si poate varia si in functie de antrenament.

De exemplu, la tineri sanatosi, 0,3 g de proteina din zer/kg corp si 0,4 g de leucina pe kg/corp stimuleaza la maxim sinteza proteinelor. La persoanele mai in varsta dozele trebuie sa fie mai mari, din cauza rezistentei anabolice (absortie mai proasta, sensibilitate mai scazuta).
In 2012, un studiu din "British Journal of Nutrition" sustinea ca este nevoie de o doza de 40 g de proteina din zer (0,5 g/kg corp) pentru a creste la maxim sinteza proteinelor la persoane in varsta. 

Un stidu recent, din august 2016, indica ca ar trebui sa dublam aceste cantitati daca facem un antrenament epuizant, precum un full-body cu greutati mari.

Probabil ca este adevarat, cel mai indicat este dozarea proteinei din zer in functie de efortul depus, antrenamentele multi-articulare de o mare intensitate crescand necesitatile corpului. Dar pentru majoritatea celor care vin la sala 0,3 g de proteina din zer pe kilogram corp ramane cea mai buna optiune.

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