10.23.13 kin 110 class notes- Alanine and BCAA’s enter energy pathso Glycogen glucose (alanine ) pyruvate (other: BCAA’s ) acetyl coAo Triglyceride …- Entry of a.a. can replace some of the pyruvate and acetyl CoA coming from CHOo In most situations, contribution from PRO is 3-7% of total energyo What situations increase that? Exercise- Exercise?o Use of PRO goes upo Higher intensity, more it increaseso Increased use of PRO is closely tied to lower amounts of muscle glycogen- Sweat urea nitrogen (mg/hr) vs experimental treatmentso Estimate use of PRO from sweat Nitrogeno Race horses: when loaded with carbohydrate, less nitrogeno Carbohydrate depleted, much more nitrogen- Oxidation of leucine vs timeo When CHO consumed use of PRO for energy goes down- Any situation that CHO availabilityo Exercise: esp. long duration or high intensityo Fating (even 10-12 hours without food) Use up 50% of inner glycogen- Low energy or low CHO diets:o Lower availability of CHO so greater use of proteino Both diets cause rapid weight loss because of loss of proteino Pro 4 kcal/go Fat 9 kcal/g- How much PRO does anyone need?o What do you do first?- Step 1: measure excretiono Assume what is excreted equals what you need to replaceo PRO excretion- Human volunteerso 0 protein dieto measure all sources of protein excretiono urine, feces, sweat, dead skin, other- protein excretion (g of PRO/kg/day) vs dayso minimal PRO excretion is 6.4 g PRO/kg/dayo 130 lb person = 24 g/dayo 200 lb person = 36 g/day- whats next?o Feed 6.4 g PRO/kg/day and see if it keeps them in balanceo Doesn’t worko Isn’t enough because- People adjust to low intake by conserving o Hair stops growingo Recycle amino acids, etc- Surplus, balance, deficito Gram protein/kg body weight per day- Is this the RDA for PRO?o 0.8 g PRO/kg/day- RDA sufficient for athletes in training?o Probably NOT PRO needed to increase muscle mass (resistance/power athletes) PRO to balance the increased use when glycogen is low (endurance athletes) PRO for repair of muscle damage (endurance & power athletes)- What are requirements?o Endurance and strength athletes: 1.2-1.5 g PRO/kg?dayo 130 lb person – - do athletes need protein supplements?o Athletes need to eat more food- Sedentary person 70 kg, eats 2000 kcal/day gets 15% of energy from PROo 15% of 2000 kcal = 300 kcal PRO/4 kcal/g = 75 grams PRO = 1.05 g PRO/kg/dayo athlete who also weighs 70 kg gets 15% OF ENERGY FROM PRO, east 3000 kcal/day? 450 = 112 g PRO/day 1.5 g PRO/kg
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