Creatine

I have mentioned before that I'm taking a course called metabolism and regulation. Well today we learned about a cool molecule called creatine which gives your muscles some extra energy during exercise. Normally, we undergo cellular respiration in order to produce a type of energy currency in our bodies- ATP (adenosine triphosphate). The vital component of ATP are its three phosphate groups which is where the energy is stored. When our muscles are moving, the ATP molecules donate one of their phosphate groups and in turn become ADP (adenosine triphosphate). These ATP molecules are present all over our bodies and are needed for a lot of different purposes, from helping move molecules in our cells, to giving a kick off for the glycolysis portion of cellular respiration to driving enzymatic reactions within our bodies.

Food--> glucose--> ATP--> life! YaY! So why in the world would we need this creatine? Well when we exercise our muscles can use 100x more ATP then when we're at rest. So as a result you deplete your energy sources and get tired. Of course, cellular respiration is still being carried out but remember that the lack of oxygen leads to anaerobic cellular respiration. This is a problem because in normal cellular respiration about 35 ATP are made per glucose molecule while during anaerobic cellular respiration you only get 2 ATP. Our bodies have developed a clever mechanism to store some of our excess energy by attaching the phosphate group to creatine to form phosphocreatine. Then during exercise, this phosphate of the phosphocreatine is transferred unto an ADP molecule (recall: ATP molecule that lost one of its phosphates) which then keeps your muscles going. YaY energy!

This is the reason why some athletes do what is called creatine loading where they consume either foods rich in creatine or take synthesized creatine to boost up their energy storage. Where is creatine found? Mainly in lean red meat and some fish, specifically tuna and salmon (if anyone here is vegan/ vegetarian I'm curious if you guys know any alternative sources of creatine?) However, the quantities of creatine in food are generally insufficient and supplements are required. I have never tried creatine loading before so I won't talk about that, but wow I just love it when the stuff you learn in school is applicable to everyday life.