Številnim izmed nas kofein predstavlja del vsakdanje prehrane. Je ena izmed najpogosteje zaužitih molekul na svetu in najdemo ga v več kot 60 rastlinskih vrstah, med katerimi so najbolj znani kava, čaj, yerba mate, guarana in orešček kola.
Športnikom lahko kofein predstavlja ergogeni pripomoček. Njegovo učinkovitost so aprila 2011 potrdili tudi evropski znanstveni strokovnjaki iz EFSA (Evropske agencije za varnost hrane). Kofein dokazano:
- izboljša rezultate in vzdržljivost,
- zniža ravni zaznanega napora med vadbo.
Kofein je obravnavan v številnih člankih in v najnovejših je njegov ergogeni učinek tudi potrjen: Bazzuchi I et al. (2011), Conger SA et al. (2011), Duvnjak-Zaknich DM et al. (2011), Irwin C et al. (2011), Ganio MS et al. (2009), Glaister M et al. (2008), Carr A et al. (2008).
Po zaužitju absorpcija kofeina doseže najvišjo raven po 30 do 60 minutah (Paluska SA, 2003), vendar njegov učinek lahko traja še več ur po zaužitju (Bell DG in McLellan TM, 2002). Večina študij, ki so pokazale učinkovitost kofeina, je bila izvedena pri odmerkih 3 do 4 mg/kg telesne teže; nekaj študij je bilo pozitivnih pri nižjih odmerkih (1–2 mg/kg) (Burke LM, 2008; Jenkins NT et al., 2008). Pri odmerkih, višjih od 3–4 mg/kg, pa učinek ni večji.
Čeprav zaužitje 400 mg kofeina/dan ne predstavlja bistvenega tveganja za zdravje ljudi (Nawrot P et al., 2003), lahko pri določenih posameznikih nastopijo stranski učinki, zlasti pri osebah, ki ne uživajo kofeina, in sicer pri odmerkih 100 do 160 mg kofeina (tremor, tesnoba, razdražljivost itd.).
Zanimivo je tudi omeniti, da so znanstveniki (Pedersen DJ et al., 2008) dokazali pozitiven učinek kofeina na regeneracijo mišic po vzdržljivostni vadbi in zlasti na obnovo glikogenskih zalog v mišicah po vadbi, če se ga zaužije skupaj z ogljikovimi hidrati. Ti učinki so bili zaznani pri višjih odmerkih kofeina (8 mg/kg telesne teže), da pa bi ugotovili, ali so nižji odmerki enako učinkoviti, je treba opraviti dodatne študije.
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Scientific Opinion on the substantiation of health claims related to caffeine and increase in physical performance during short-term high-intensity exercise (ID 737, 1486, 1489), increase in endurance performance (ID 737, 1486), increase in endurance capacity (ID 1488) and reduction in the rated perceived exertion/effort during exercise (ID 1488, 1490) pursuant to Article 13 (1) of Regulation (EC) No 1924/2006, EFSA Journal 2011;9(4):2053 [24 pp.]. doi:10.2903/j.efsa.2011.2053
