Protein requirements for exercise Flashcards
Name some essential amino acids
Histidine, methionine, lysine, phenylalanine, trptophan, threonine
what are complete proteins
they are proteins that contain all essential amino acids
what are incomplete proteins
they are proteins that are deficient in one or more amino acid
what are complementary proteins
it is when two incomplete proteins are eaten together to result in one complete protein
ex: dairy and grains
dairy and nuts
Protein digestion
Stomach and liver
proteases
stomach = highly acidic
- activates pepsinogen > > pepsin
- kills pathogens
- increase absorption of ca and iron
- denature protein
Pepsin in the stomach, other proteases (esp pancreatic juices ex: trypsin) in small intestine
Continues at brush boarder
Once absorbed AAs travel in the blood to the liver
Once protein is absorbed the possibilities are:
- protein synthesis
- make hormones and neurotransmitters
-can have AA group removed and oxidized for energy - can enter a certain point of TCA cycle
-used to form glucose and fatty As - The amino group can be removed and accepted by a keto-acid to form another AA (transamination) or removed to form free ammonia (deamination) which is used to form glutamine or converted to urea in the liver and excreted.
Protein for athletes: Resistance training
appears to result in an upregulation of muscle protein synthesis for at least 24 hours and increased sensitivity to dietary protein at this time
Protein for athletes: Endurance training
can increase the oxidation of AAs when CHO and fat stores are used up. Endurance athletes also need to repair damaged muscle protein. Signaling processes may also guide development of important proteins such as proteins in the mitochondria
Digestion rate of different protein types
Whey- Fast
Casein- Slow
Soy- Faster than casein but slower than whey
what does BCAA stand for and what are the 3 BCAAs
branch chain AAs
Valine, leucine and isoleucine
what does BCAAs claim to do
claim to reduce net muscle breakdown in muscle during exercise, increase muscle mass, healthy immune system, reduce fatigue, and enhance performance via brain effects
What is the central fatigue hypothesis
serotonin in brain - chemical thought to contribute to the perception of fatigue
Made from tryptophan
BCAAs and tryptophan have the same carrier to the brain so in theory if you increase BCAAs, less free tryptophan into brain - less serotonin.
Possibly effects of a very high protein diet
Increase calcium excretion in the urine- can lead to reduced bone density
Renal implications- exacerbation of existing renal disease
Dehydration- increase nitrogen in the urine
