... (except soy). McDonald L, et al. The Protein Book A Complete Guide for the
Coach and Athlete. 1st ed. Salt Lake City, UT: Lyle McDonald Publishing; 2007. 4
...
Protein and Amino Acids in Sports Nutri3on Advanced Level
1
Module II Evalua.ng Protein Quality Determining Protein Recommenda.ons for Athletes
Evalua3ng Protein Quality
3
Protein Quality § Complete protein – Contains all the essen.al AAs in amounts that meet what is required by humans to prevent deficiency • Animal proteins (except gela.n) • Dairy proteins • Soy protein
§ Incomplete protein – Too low in one or more of the essen.al AAs to support human growth and maintenance • Cannot serve as a sole source of protein in the diet without deficiency developing • Limi.ng AA (LAA) is the essen.al AA present in the lowest quan.ty in the food • Most plant proteins are incomplete proteins (except soy)
McDonald L, et al. The Protein Book A Complete Guide for the Coach and Athlete. 1st ed. Salt Lake City, UT: Lyle McDonald Publishing; 2007. 4
Protein Quality: Complementary Proteins § Complementary proteins – Combina.ons of incomplete proteins that, when added together, result in a complete protein (eg, beans and rice) • Legumes: Èmethionine, Ç lysine • Grains: Çmethionine, È lysine
– Combining a complete protein with an incomplete protein is also considered complementary • Excep.ons are milk and legumes
– Although milk has a greater amount of sulfur-‐containing AAs (ie, methionine and cysteine) per gram compared with legumes, not enough sulfur-‐containing AAs are present for an ideal AA profile when the 2 foods are consumed together
McDonald L, et al. The Protein Book A Complete Guide for the Coach and Athlete. 1st ed. Salt Lake City, UT: Lyle McDonald Publishing; 2007.
5
Protein Quality: Complementary Proteins (Cont’d) § Complementary proteins – Combining complementary proteins at each meal for vegetarians is not necessary • What maTers is the total intake of complementary proteins over the course of a day • May be more crucial for individuals wishing to op.mize meal-‐s.mulated protein synthesis in muscle – Requires full complement of essen.al AAs as well as rela.vely high leucine content to maximally s.mulate mTOR pathway
McDonald L, et al. The Protein Book A Complete Guide for the Coach and Athlete. 1st ed. Salt Lake City, UT: Lyle McDonald Publishing; 2007.
6
Progress Check—Evalua3ng Protein Quality
1. Which of the following are complete proteins that contain adequate amounts of all the essen.al amino acids for suppor.ng human growth and development? A. B. C. D. E.
Dairy protein Egg protein Soybean protein All of the above A and B only
2. Consuming rice and beans together is an example of: A. B. C. D.
Complementary proteins Corresponding proteins Complex proteins None of the above
7
Progress Check—Evalua3ng Protein Quality 1. Which of the following are complete proteins that contain adequate amounts of all the essen.al amino acids for suppor.ng human growth and development? û
A. Dairy protein
Incorrect, please review slides on Protein Quality to be7er understand the nature of different proteins.
û
B. Egg protein
û
C. Soybean protein
D. All of the above
Incorrect, please review slides on Protein Quality to be7er understand the nature of different proteins.
Incorrect, please review slides on Protein Quality to be7er understand the nature of different proteins.
Correct, animal and soy proteins are complete proteins.
û
E. A and B only
Incorrect, please review slides on Protein Quality to be7er understand the nature of different proteins.
8
Progress Check—Evalua3ng Protein Quality 2. Consuming rice and beans together is an example of:
A. Complementary proteins
Correct, rice and beans together provides enough combina?ons of proteins to be considered complete.
û û û
B. Corresponding proteins
Incorrect, please review slides on Protein Quality: Complementary Proteins to be7er understand the nature of different proteins.
C. Complex proteins
Incorrect, please review slides on Protein Quality: Complementary Proteins to be7er understand the nature of different proteins.
D. None of the above Incorrect, please review slides on Protein Quality: Complementary Proteins to be7er understand the nature of different proteins.
9
Evalua3on of Protein Quality § Two important aspects of evalua.ng protein quality – Amino acid profile (compared to “ideal” paTern) – Diges.bility of the protein • Plant proteins are oaen contained within cell walls that are resistant to human diges.on, limi.ng diges.bility • Some legumes have an.nutri.onal factors such as trypsin that also limit diges.bility Source
True Diges3bility, %
Egg
97
Milk / cheese
95
Meat / fish
94
Soy flour
86
Whole wheat
85
Corn, whole
87
Oatmeal
86
Beans
78
American mixed diet
96
Abbreviations: FAO, Food and Agriculture Organization; WHO, World Health Organization. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Fiber, Protein, and Amino Acids. Washington, DC: National Academies Press, 2005, p. 683-689. Report of the Joint FAO/WHO Expert Consultation. Protein quality evaluation. FAO Food and Nutrition Paper No 51. 1991. 10
Protein Diges3bility Corrected Amino Acid Score § Protein diges.bility corrected amino acid score (PDCAAS) is the current “gold” standard by FAO/WHO for assessing protein mg of limi3ng AA in quality PDCAAS (%)
1 g test protein
mg of same AA in 1 g of reference or “ideal” protein
True fecal diges3bility (DF; %)
– DF = (NI – NFΔ) / NI where • NI = nitrogen intake (g protein/6.25) • NFΔ = fecal nitrogen on a diet containing the protein minus fecal nitrogen on a protein-‐free diet (corrects for endogenous nitrogen)
§ Complete proteins can oaen have PDCAAS values of ≥ 1.00 – Standard prac.ce is to truncate values exceeding 1.00 to simply 1.00 Abbreviations: FAO, Food and agriculture Organization; WHO, world Health Organization. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Fiber, protein, and Amino Acids. Washington, DC: National Academies Press, 2005, p. 683-689. Schaafsma G. J Nutr. 2000;130(7):1865S-1867S.
11
Example of PDCAAS Calcula3on § Iden.fy the limi.ng AA (LAA) in a protein source
mg / g Protein
Amino Acid
Whole Wheat Flour
FNB/IOM Standard
Ra3o
His.dine
22
18
1.22
Isoleucine
40
25
1.6
Leucine
63
55
1.15
Lysine
26
51
0.51 (LAA)
Met + Cys
35
25
1.4
Phe + Tyr
81
47
1.72
Threonine
27
27
1.00
Tryptophan
11
7
1.57
Valine
43
32
1.34
FNB, Food and Nutrition Board; IOM, Institute of Medicine.
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Fiber, protein, and Amino Acids. Washington, DC: National Academies Press, 2005, p. 686-689.
12
Example of PDCAAS Calcula3on (Cont’d) § PDCAAS of whole wheat = ra.o for lysine (LAA) x diges.bility – 0.51 × 0.85 = 0.433 – Therefore, whole wheat is an incomplete protein and not suitable as a sole protein source in the diet
§ For the percent daily value (% DV) of protein on food labels, the total protein content is first corrected using PDCAAS before a % DV value is listed – % DV = amount of nutrient in 1 serving (corrected) ⁄ DV for nutrient (50 g for protein in adults)
US Food and Drug Administration. Food Labeling Guide Section 7. October 2009. Available at: http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/FoodLabelingGuide/ ucm064894.htm. Accessed July 20, 2011.
13
PDCAAS of Protein Sources
Protein Source
PDCAAS
Egg
1.0
Milk
1.0
Beef
0.92
Soy protein
1.0
Wheat
0.42
Whey protein
1.0
Casein
1.0
Peanuts
0.52
Black beans
0.75
Hoffman JR and Falvo MJ. J Sports Sci Med. 2004;3:118–130. Schaafsma G. J Nutr. 2000;130(7):1865S-1867S. 14
Limita3ons of PDCAAS for Athletes § Values above 1.0 are truncated – FAO/WHO defini.on is concerned only with mee.ng maintenance requirements – Does not account for protein intake or outcomes beyond maintenance requirements
§ Does not account for rela.ve AA differences among proteins with PDCAAS of 1.0 – For example, soy isolate and whey isolate both have PDCAAS of 1.0, yet soy has 50% the threonine (an essen.al AA) of whey
§ Ileal diges.bility may vary among protein sources – AAs not absorbed by the distal intes.ne can subsequently be consumed by bacteria in the colon; therefore, fecal diges.bility may not accurately reflect AA uptake from a protein source
FAO, Food and agriculture Organization; WHO, world Health Organization. Millward DJ, et al. Am J Clin Nutr. 2008;87:1576S-1581S. 15
Protein Efficiency Ra3o for Protein Quality § Protein efficiency ra.o (PER) – Assesses weight gain of growing animals on a par.cular protein source (eg, rats, chicks) • Diet containing about 10% protein is fed for ~10 days
– PER = weight gain (g)/protein consumed (g) – Not suitable as an index for human consump.on • Human metabolism oaen varies substan.ally from animals
Ferreira Costa Leite CD, et al. Nutr Hosp. 2011;26(2):415-420. 16
Nitrogen Balance for Protein Quality § Nitrogen intake (from protein) minus nitrogen excre.on equals nitrogen balance – Nitrogen balance: Nitrogen intake = nitrogen losses – Nega.ve nitrogen status: Nitrogen intake < nitrogen losses – Posi.ve nitrogen status: Nitrogen intake > nitrogen losses
§ Nitrogen balance is a whole body concept – Does not give specific informa.on on flux of protein/AA pool within individual .ssues/organs
§ FAO/WHO has set protein requirements based on nitrogen balance experiments
Rand WM, et al. Am J Clin Nutr. 2003;77:109-127.
17
Nitrogen Balance in Clinical Studies § Typically, healthy individuals were on 2 diets – Diet with protein of interest versus protein-‐free diet – Test diets were above, below, and near predicted protein requirement – Nitrogen losses in feces and urine measured • Other losses (eg, skin) oaen es.mated
Irwin MI and Hegsted DM. J Nutr. 1971;101(4):539-566.
18
Calcula3ng Nitrogen Balance § General nitrogen-‐status formula
Nitrogen status = NI – [(U -‐ UE) + (F – FE) + S]
− Where
• NI is nitrogen intake • U and F are urinary and fecal nitrogen losses, respec.vely • UE and FE are endogenous urinary and fecal nitrogen losses during a nitrogen-‐free diet • S is nitrogen loss from sloughed skin cells, sweat, bodily secre.ons
Gropper SS, et al. Chapter 6 Protein in Advanced Nutrition and Human Metabolism. 5th ed. Belmont, CA: Wadsworth, CENGAGE Learning.; 2009. p 237-238. 19
Calcula3ng Nitrogen Balance (Cont’d) § Clinical nitrogen-‐status formula
Nitrogen status = (g protein intake/6.25) – (UUN + 4)
− Where
• Nitrogen intake is es.mated; divide protein intake by 6.25 • UUN is 24-‐hour urinary urea nitrogen loss
− Added to 4, which es.mates other nitrogenous urea compounds and non-‐urea nitrogen losses)
§ Example – Individual with protein intake of 85 g, UUN of 9.9 mg/mL, and 24-‐hour urine volume of 1,000 mL • Nitrogen intake: 85 g/6.25 = 13.6 g • UUN: 9.9 mg/mL × 1,000 mL = 9,900 mg OR 9.9 g • Nitrogen balance: 13.6 – (9.9 + 4) = − 0.3 − Nega.ve nitrogen balance indicates state of protein loss
Lee, RD and Nieman, DC. Nutritional Assessment. 4th ed. New York, NY: McGraw Hill; 2006. p 323. 20
Considera3ons for Nitrogen Balance § Measurements are difficult and oaen imprecise § Urine and fecal collec.ons must fully account for 24-‐hr period – Difficult in prac.ce
§ Poor es.mates of true nitrogen loss oaen result in an overes.ma.on of nitrogen reten.on § Non-‐protein energy intake can influence results – Carbohydrate and fat are protein-‐sparing – If energy is inadequate, AAs will be used for oxida.on (fuel) instead of for synthesis of new proteins, thus nitrogen reten.on is reduced 21
Biological Value for Protein Quality § Biological value (BV) measures how much nitrogen is retained in the body § Similar to nitrogen balance concept – 2 diets (one with protein, the other protein-‐free) that are fed to either humans or animals for 7 to 10 days – Urinary and fecal collec.ons are assessed
§ Calcula.on NI – (U – UE) – (F – FE) Nitrogen retained BV = X 100 = X 100 Nitrogen absorbed N – (F – F ) – Where
I
E
• NI is nitrogen intake • U and F are urinary and fecal nitrogen losses, respec.vely • UE and FE are endogenous urinary and fecal nitrogen losses during a nitrogen-‐free diet
– Maximum biological value = 100 (indicates all nitrogen absorbed is retained)
§ Similar limita.ons for nitrogen balance apply to biological value – Meaningful for whole diets, but not individual components of mixed diets since limi.ng AAs can differ between sources Gropper SS, et al. Chapter 6 Protein in Advanced Nutrition and Human Metabolism. 5th ed. Belmont, CA: Wadsworth, CENGAGE Learning.; 2009. p 239. 22
Biological Value of Selected Foods Protein Source
Biological Value
Egg, whole
93.7
Milk
84.5
Fish
76.0
Beef
74.3
Soybeans
72.8
Rice, polished
64.0
Wheat, whole
64.0
Corn
60.0
Beans, dry
58.0
Food and Agriculture Organization of the United Nations. Amino Acid Content of Foods and Biological Data on Proteins. Nutritional Study 24. Rome, Italy; 1981. Available at: http://www.fao.org/DOCREP/005/AC854T/AC854T74.htm#chII.I.7. Accessed; July 20, 2011. 23
Net Protein U3liza3on for Protein Quality § Net protein u.liza.on is similar to nitrogen balance and biological value concepts – 2 diets (one with protein, the other protein-‐free) that are fed to either humans or animals for 7 to 10 days • Total carcass nitrogen (TCN) is oaen measured in animal studies § NPU = (TCN on test protein – TCN on protein-‐free diet) / N intake – Urinary and fecal collec.ons are assessed
§ Calcula.on NPU =
NI – (U – UE) – (F – FE) NI
X 100
=
Nitrogen retained Nitrogen intake
X 100
– Where • NI is nitrogen intake • U and F are urinary and fecal nitrogen losses, respec.vely • UE and FE are endogenous urinary and fecal nitrogen losses during a nitrogen-‐free diet Gropper SS, et al. Chapter 6 Protein in Advanced Nutrition and Human Metabolism. 5th ed. Belmont, CA: Wadsworth, CENGAGE Learning.; 2009. p 239. 24
Leucine Content as an Addi3onal Indicator of Protein Quality § A recent animal study has shown that the leucine content of a meal determines its capacity to maximally s.mulate muscle protein synthesis1 – Whey protein (higher leucine) ac.vates protein synthesis more than wheat protein (lower leucine)
§ Human studies have shown that leucine-‐rich protein sources such as whey are beTer at s.mula.ng muscle growth than sources with less leucine, such as soy2,3 – For example, compared with soy protein, whey promoted more muscle protein synthesis • By 18% at rest (P = .067) • By 31% following resistance exercise (P < .05)
1. Norton LE, et al. J Nutr. 2009;139(6):1103-1109. 2. Hartman JW, et al. Am J Clin Nutr. 2007;86(2):373-381. 3. Tang JE, et al. J Appl Physiol. 2009;107(3):987-992. 25
Leucine Content of Selected Protein Sources
Source
Leucine, g/100 g
Total Essen3al AAs, g/ 100 g
Soy protein isolate
8.2
36.0
Egg protein
8.4
42.3
Casein
8.9
40.7
Milk protein isolate
10.3
42.7
Whey protein isolate
12.2
49.2
Whey protein hydrolysate
14.2
49.8
Hulmi JJ, et al. Nutr Metab (Lond). 2010;7:51.
26
Considera3ons for Protein Sources, Quality, and Turnover § Casein, whey, and egg are all high-‐quality proteins capable of suppor.ng muscle growth § Whey protein supplementa.on appears to be par.cularly good at s.mula.ng muscle protein synthesis – Leucine content highest (in addi.on to speed of diges.on)
§ Casein may reduce muscle protein breakdown (slow diges.ng, high quality source ideal before bed.me) § Soy is also high quality according to the standard defini.on, but may be less ideal due to lower leucine content § Combina.on of protein sources are ideal to get wide range of effects
Hulmi JJ, et al. Nutr Metab (Lond). 2010;7:51. 27
Protein Quality Summary § PDCAAS is the “Gold Standard” for protein quality – Accounts for diges.bility as well as amount of essen.al AAs • Animal, dairy, and soy are of highest quality by this defini.on
§ Nitrogen balance – Used to determine protein requirements to prevent deficiency in humans (RDA) – Does not account for different AA composi.ons among protein sources – Poten.ally flawed due to measurement errors
§ PER, BV, and NPU are not as robust in determining true protein quality – More oaen used in agriculture
§ Leucine content of a protein source may determine the protein source’s ability to s.mulate protein synthesis in muscle
Abbreviations: PDCAAS, protein digestibility corrected amino acid score; PER, protein efficiency ratio; BV, biological value; NPU, net protein utilization; RDA, recommended dietary allowance.
28
Progress Check—Evalua3ng Protein Quality 1. The protein diges.bility corrected amino acid score takes into account amino acid content and diges.bility and is the “gold” standard for protein quality. A. B.
True False
2. Important aspects of protein quality may include: A. B. C. D.
Amino acid content, especially leucine Diges.bility Nitrogen balance All of the above
3. Other methods of determining protein quality include: A. B. C.
Protein efficiency ra.o only Biological value, net protein u.liza.on, and leucine content Nitrogen balance, protein efficiency ra.o, net protein u.liza.on, and biological value D. A and B
29
Progress Check—Evalua3ng Protein Quality 1. The protein diges.bility corrected amino acid score takes into account amino acid content and diges.bility and is the “gold” standard for protein quality.
False
A. True
Correct, the PDCAA is currently the standard method for protein quality, although it does have limita?ons.
û
B.
Incorrect, please review slide Protein Diges?bility Corrected Amino Acid Score to be7er understand the PDCAA method for protein quality.
30
Progress Check—Evalua3ng Protein Quality 2. Important aspects of protein quality may include:
û
A. Amino acid content, especially leucine
û
B. Diges.bility
Incorrect, please review slide Evalua?on of Protein Quality to be7er understand protein quality.
Incorrect, please review slide Evalua?on of Protein Quality to be7er understand protein quality.
û
C. Nitrogen balance
Incorrect, please review slide Nitrogen Balance for Protein Quality to be7er understand protein quality.
D. All of the above Correct, protein quality may include all characteris?cs.
31
Progress Check—Evalua3ng Protein Quality 3. Other methods of determining protein quality include: û
A. Protein efficiency ra.o only
Incorrect, please review slide Protein Quality Summary to be7er understand all of the methods for determining protein quality.
û
B. Biological value, net protein u.liza.on, and leucine content
Incorrect, please review slide Protein Quality Summary to be7er understand all of the methods for determining protein quality.
C. Nitrogen balance, protein efficiency ra.o, net protein u.liza.on, and biological value
Correct, both glycogen replenishment and protein synthesis in muscles benefit from immediately inges?ng protein post-‐exercise.
û
D. A and B Incorrect, please review slide Protein Quality Summary to be7er understand all of the methods for determining protein quality.
32
Determining Protein Recommenda3ons for Athletes
33
Recommended Daily Requirement for Protein § Current RDA for protein is 0.8 g/kg body weight per day – ~65 g/day for a 180 lb (82 kg) individual – ~47 g/day for a 130 lb (59 kg) individual
§ The RDA was calculated using nitrogen balance studies – Defines amount of protein required to maintain nitrogen balance in a healthy adult • Consume just enough protein to not be deficient
§ Most Americans appear to consume adequate protein by this defini.on – Median protein intake for all adult age and gender groups ranged from 55 to 101 g/day – Adequate intake does not necessarily = op.mal for health or performance USDA National Agricultural Library Food and Nutrition Information Center. Available at: http://fnic.nal.usda.gov/nal_display/index.php?info_center=4&tax_level=3&tax_subject=256&topic_id=1342&level3_id=5140 U.S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Food Surveys Research Group (Beltsville, MD). Continuing Survey of Food Intakes by Individuals 1994-96, 1998 and Diet and Health Knowledge Survey 1994-96.
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Protein Requirements
§ The current RDA for protein may be too low – Nitrogen balance studies oaen overes.mate nitrogen reten.on • Therefore, the nitrogen (protein) requirement may be underes.mated
– Reanalysis of exis.ng nitrogen balance studies suggests that the popula.on requirement is ~1.0 g/kg body weight per day • Calcula.ons using a new method (Indicator Amino Acid Oxida.on) suggest that the popula.on requirement is ~1.2 g/kg body weight per day
– These results are not official recommenda.ons, but they suggest that the current guideline may not be perfect and merits con.nuous reevalua.on
Abbreviation: RDA, recommended dietary allowance. Elango R, et al. Curr Opin Clin Nutr Metab Care. 2010;13(1):52-57. 35
Preven3ng Protein Deficiency Versus Op3mal Outcome § The RDA for protein is set to prevent protein deficiency (maintenance) in healthy adults § The RDA for protein does not consider poten.al benefits that might be obtained from consump.on beyond that needed simply to maintain nitrogen balance – What is the op.mal protein intake for • Skeletal muscle func.on? • Bone health? • Athle.c performance?
Abbreviation: RDA, recommended dietary allowance. 36
Protein Intake Recommenda3ons for Athletes § American College of Sports Medicine (ACSM)/American Diete.c Associa.on (ADA) – Endurance athletes, 1.2 to 1.4 g/kg per day • Based on nitrogen balance studies – Increased protein oxida.on during endurance exercise
– Strength athletes, 1.2 to 1.7 g/kg per day • Essen.al AAs are needed to support muscle growth, par.cularly during early phase of training when most significant gains in muscle occur and protein u.liza.on is less efficient
– Despite increased recommenda.ons, ACSM does not state that protein supplementa.on has a posi.ve impact on athle.c performance
ACSM and ADA. Med Sci Sports Exerc. 2009;41(3):709-731.
37
Nitrogen Balance and Athletes (1 of 3) § The RDA for protein (0.8 g/kg) is probably insufficient for maintaining nitrogen balance in either strength or endurance athletes – 0.97 to 1.37 g/kg per day for endurance athletes – 0.82 to 1.43 g/kg per day for strength athletes (experienced, novice)
§ Endurance athletes may require more protein than strength athletes to maintain nitrogen balance
Nitrogen balance, g/kg/day
– Higher energy requirements dictate greater protein needs – Contrac.ng skeletal muscles oxidize BCAAs for energy produc.on – Adequate caloric intake to match physical demands is key in order to spare AAs for muscle protein synthesis
Activity type Abbreviations: RDA, recommended dietary allowance; BCAA, branched-chain amino acids. Tarnopolsky MA, et al. J Appl Physiol. 1988;64(1):187-193.
38
Nitrogen Balance and Athletes (2 of 3) § Experienced weight liaers require less protein intake per kg of lean body mass than that of novices § Less poten.al expansion of muscle mass to be added in experienced weight liaers – In the first month of training, 1.4 g protein/kg versus 2.4 g protein/kg for novices • Calculated 1.43 g/kg per day for nitrogen balance
– Nitrogen balance no longer had significant rela.onship with protein intake above 2.0 g protein/kg – Increased AA oxida.on generally seen above 2.0 g/kg • Generally indicates no further metabolic benefit, at which point addi.onal protein is used purely as a substrate for energy produc.on/storage
– No apparent effect of >2.0 g protein/kg on strength
Tarnopolsky MA, et al. J Appl Physiol. 1988;64(1):187-193. Lemon PW, et al. J Appl Physiol. 1992;73(2):767-775.
39
Nitrogen Balance and Athletes (3 of 3) § Addi.onal protein intake can account for individual variability (1-‐2 standard devia.ons) and for promo.ng posi.ve nitrogen status rather than nitrogen balance – 1.5 to 1.8 g/kg for strength athletes • This range should be adequate for endurance athletes as well
– ~2.0 g/kg appears to be upper limit before protein intake has no addi.onal benefit – Energy intake is an important influence (male vs female) • Requirement may go beyond 2.0 g/kg if energy intake is inadequate
Tipton KD and Wolfe RR. J Sports Sci. 2004;22(1):65-79. 40
Vegetarian Diets § Most vegetarian athletes meet the RDA for protein intake (0.8 g/kg per day) – Like non-‐vegetarian athletes, the protein requirement for suppor.ng muscle growth and func.on is probably higher than the RDA
§ Protein quality of non-‐animal/dairy sources is reduced – Vegetable/legume proteins may be limited in the essen.al AAs lysine, threonine, tryptophan, or methionine – Vegetable/legume proteins are more poorly digested
§ ACSM/ADA recommends 1.3 to 1.8 g/kg of protein per day for vegetarian athletes – Vegetarian protein needs are likely higher than omnivore protein needs at all ac.vity levels
Abbreviations: RDA, recommended dietary allowance; ACSM, American College of Sports Medicine; ADA, American Dietetic Association. Tipton KD and Witard OC. Clin Sports Med. 2007;26(1):17-36. ACSM and ADA. Med Sci Sports Exerc. 2009;41(3):709-731. 41
How Much Protein Are Athletes Ea3ng? § Many athletes may already meet or exceed protein recommenda.ons § Strength athletes in par.cular may believe that much larger protein intakes are necessary for increasing muscle mass – Intakes at 4 to 6 g/kg range are not uncommon – It is possible that this much protein intake could adversely affect the nutrient quality of the overall diet
Protein intake of 0.8 to 2 g/kg per day is safe in healthy individuals Protein intake above 2 g/kg per day is not recommended due to lack of benefit and potential for adverse health effects
Tipton KD. Proc Nutr Soc. 2011;70(2):205-214. 42
Poten3al Downside to “High Protein” Diets (1 of 2) § Hydra.on status – Ea.ng protein beyond requirements can result in • Increased protein use for energy • Increased fat storage
– The body must excrete the nitrogen from protein in urine (as urea) – Increased urinary output increases the likelihood of dehydra.on
§ Diets very high in protein may lack appropriate amounts of carbohydrate, fiber, and some vitamins/minerals – Could impair exercise performance – Could increase long-‐term risk of diseases such as colon cancer • Possibly due to lack of fiber or increased intake of red meat
§ Excessively faTy protein sources could increase risk of cardiovascular disease – Make sure protein sources chosen are mostly lean • For example, salmon is more desirable than a rib-‐eye steak
Tipton KD. Proc Nutr Soc. 2011;70(2):205-214. 43
Poten3al Downside to “High Protein” Diets (2 of 2) § Kidney disease – No good evidence of damage in individuals with healthy kidneys – Protein-‐rich diets are high in phosphorus, which can be detrimental to individuals with kidney disease • Primarily a concern with elderly or sick individuals, as opposed to healthy athletes
§ Bone health – Higher protein diets may increase calcium loss in urine • However, gut absorp.on of calcium is likely improved, so there may be no net difference
– Elevated protein diets appear to have either no or a slightly beneficial effect on skeletal health
Tipton KD. Proc Nutr Soc. 2011;70(2):205-214.
44
Summary of Protein Recommenda3ons § Daily Recommended Intake is 0.8 g/kg per day (2002) – No recommenda.on for increase in athletes
§ American College of Sports Medicine
– Endurance: 1.2 to 1.4 g/kg per day – Strength athletes: 1.2 to 1.7 g/kg per day
§ Vegetarians may have higher dietary supplementa.on protein needs than omnivores § Protein intakes up to 2.0 g/kg per day are generally safe in healthy adults and may be beneficial – Many athletes may already unconsciously eat this amount of protein
§ Few convincing data show that > 2 g/kg per day is helpful – May actually increase risk of adverse events
§ A par.cular protein intake goal is difficult to establish
– Influenced by energy intake and factors such as adapta.on and desire to increase lean body mass versus maintenance 45
Progress Check—Determining Protein Recommenda3ons for Athletes 1. The current American College of Sports Medicine (ACSM) recommenda.on for an athlete’s minimum protein intake is 1.2 g/kg body weight per day. A. B.
True False
2. What is a poten.al downside to a “high-‐protein” diet? A. B. C. D.
Dehydra.on Cons.pa.on High blood cholesterol if faTy protein sources are chosen All of the above
46
Progress Check—Determining Protein Recommenda3ons for Athletes 1. The current American College of Sports Medicine (ACSM) recommenda.on for an athlete’s minimum protein intake is 1.2 g/kg body weight per day.
False
A. True
Correct, the minimum protein intake is 1.2 g/kg body weight per day.
û
B.
Incorrect, please review slide Protein Intake Recommenda?ons for Athletes to be7er understand protein intake recommenda?ons.
47
Progress Check—Determining Protein Recommenda3ons for Athletes 2. What is a poten.al downside to a “high-‐protein” diet?
û
A. Dehydra.on
û
B. Cons.pa.on
Incorrect, please review slides on Poten?al Downside to “High-‐Protein” Diets to be7er understand the possible side effects of a high-‐protein diet.
Incorrect, please review slides on Poten?al Downside to “High-‐Protein” Diets to be7er understand the possible side effects of a high-‐protein diet.
û
C. High blood cholesterol if faTy protein sources are chosen
Incorrect, please review slides on Poten?al Downside to “High-‐Protein” Diets to be7er understand the possible side effects of a high-‐protein diet.
D. All of the above Correct, all of the above effects may occur during a high-‐protein diet.
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Amino Acid Intake Recommenda3ons § Omnivorous diets are likely to meet AA requirements as long as protein requirements are met § Vegetarians should be cognizant of complementary protein sources throughout the day to prevent deficiency of par.cular AAs a
Amino Acid
RDA (mg/kg/day)
His.dine
18
Isoleucine
23
Leucine
49
Lysine
48
Methionine + cysteine
23
Phenylalanine + tyrosine
48
Threonine
28
Tryptophan
8
Valine
32
Abbreviations: RDA, recommended dietary allowance. a Based on maintenance protein requirement and determined by multiplying total protein maintenance needs in adults by amino acid content of whole body protein.
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Fiber, Protein, and Amino Acids. Washington, DC; National Academies Press, 2005, p. 687.
49
Poten3al Risks of AA Supplementa3on (1 of 2) § Taking large doses of a single AA can affect the absorp.on of other AAs – Certain AAs may u.lize the same system for transport/absorp.on • High levels of one AA can inhibit the absorp.on of other AAs dependent on the same system – In chicks, excessive doses of lysine caused increased plasma lysine levels while plasma arginine levels decreased (and vice versa) – Branched-‐chain AAs leucine, isoleucine, and valine are oaen ingested in a naturally occurring 2:1:1 ra.o to ensure that none of the 3 are depleted by the others
§ Large single doses of AAs may be poorly absorbed and lead to diarrhea
Bröer S. Physiol Rev. 2008;88(1):249-286. Jones JD, et al. J Nutr. 1967;93(1):103-116. 50
Poten3al Risks of AA Supplementa3on (2 of 2) § Free AAs in food products oaen create biTer flavors – AA pills don’t have this issue, but dose of AA in pills is oaen small
§ In 1989, there were many cases of a painful and some.mes fatal disease (eosinophilia myalgia syndrome) linked to tryptophan supplements – Likely due to contamina.on • Always good to know source and quality of nutri.onal supplements
Adibi SA. J Clin Invest. 1971;50(11):2266-2275. Ney KH. Bitterness of Peptides: Amino Acid Composition and Chain Length in Food Taste Chemistry. Washington, DC; American Chemical Society; 1979. p 149-173. Philen RM, et al. Am J Epidemiol. 1993;138(3):154-159. 51
Sports Nutri3on Claims for AAs and Deriva3ves (1 of 4)
The scien.fic basis for the support of these claims can be found in the ergogenic aids modules on the EAS Academy website § Arginine and citrulline (precursor of arginine) – Increased nitric oxide for improved blood flow to muscle – Improved clearance of ammonia via urea cycle – Improved exercise performance – Citrulline decreases muscle soreness
§ Arginine, ornithine, lysine – S.mula.on of growth hormone release
Cynober L. J Nutr. 2007;137:1646S-1649S. Chromiak JA and Antonio J. Nutrition. 2002;18(7-8):657-661. 52
Sports Nutri3on Claims for AAs and Deriva3ves (2 of 4) § Beta-‐alanine – Forms the dipep.de carnosine when bonded to his.dine • Buffers muscle pH to improve endurance
– Not actually incorporated into structural body proteins like alanine
§ Crea.ne – Increased anaerobic performance – Increased strength and muscle mass
§ Glutamine and its precursor alpha-‐ketoglutarate (AKG) – Boost immune func.on – Fuel for intes.nal cells – Transport of nitrogen groups in plasma – Possible anabolic effects Artioli GG, et al. Med Sci Sports Exerc. 2010;42(6):1162-1173. Juhn M. Sports Med. 2003;33(12):921-939. Newsholme P, et al. Braz J Med Biol Res. 2003;36(2):153-163. 53
Sports Nutri3on Claims for AAs and Deriva3ves (3 of 4) § Leucine/Branched-‐Chain AAs (BCAAs) – Leucine s.mulates muscle protein synthesis – BCAAs can serve as an energy source during ac.vity – Preven.on of fa.gue – Reducing muscle soreness – BCAAs are popular as a supplement among athletes – BCAA doses of ~2 to 60 g/day have been used in research studies – Doses of ≥ 30 g/day are imprac.cally high compared to amounts found in typical commercial supplements • 1 tablet typically contains 100 mg leucine, 100 mg valine, and 50 mg isoleucine Gleeson M. J Nutr. 2005;135:1591S-1595S. Negro M, et al. J Sports Med Phys Fitness. 2008;48(3):347-351. Gijsman HJ, et al. Psychopharmacology (Berl). 2002;160(2):192-197. Koba T, et al. J Sports Med Phys Fitness. 2007;47(3):316-322. Coombes JS and McNaughton LR. J Sports Med Phys Fitness. 2000;40(3):240-246. Gualano AB, et al. J Sports Med Phys Fitness. 2011;51(1):82-88.
54
Sports Nutri3on Claims for AAs and Deriva3ves (4 of 4) § Leucine breakdown products – Beta-‐hydroxy-‐beta-‐methylbutyrate (HMB) and alpha-‐ketoisocaproate (alpha-‐KIC) • Decreased muscle protein breakdown • Increased muscle mass and strength
§ Taurine – An.oxidant effects – Improved heart func.ons – Insulin ac.ons
Zanchi NE, et al. Amino Acids. 2011;40(4):1015-1025. Franconi F, et al. Curr Opin Clin Nutr Metab Care. 2006;9(1):32-36. Schaffer SW, et al. J Biomed Sci. 2010;17(suppl 1):S2. 55
Example: Quan3ty of Amino Acids in Food § 1 cup of low fat coTage cheese (2%) has 31 g protein – This translates to 31,000 mg of amino acids – The branched-‐chain amino acid content of the coTage cheese (leucine + isoleucine + valine) is 6,942 mg (6.9 g)
§ Whole protein sources are best (may be less expensive)
Pennington JAT, et al. Bowes and Church’s Food Values of Portions Commonly Used. 17th ed. Philadelphia PA: Lippincott, Williams, & Wilkins; 1998. p 30 and 318. 56
Is Protein Used for Energy in Athletes? § In general, the body prefers to spare its endogenous protein stores (skeletal muscle, etc) from oxida.on for energy produc.on – Only in condi.ons of starva.on, extreme energy requirements (eg, ultramarathons), or was.ng condi.ons such as cancer will the body break down muscle for energy
§ Consider fight or flight response – Difficult to avoid danger (eg, run from a bear) or obtain food (eg, catch a fish) if muscle protein is sacrificed as fuel for energy
§ However, exogenous (dietary) protein is commonly used as fuel under certain condi.ons (eg, during endurance exercise, which can deplete carbohydrate stores in muscle)
Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman & Co.; 2002. Wagenmakers AJ. Exerc Sport Sci Rev. 1998;26:287-314. 57
Is Protein Used for Energy in Athletes? (Cont’d) § 6 AAs are metabolized in res.ng muscle (leucine, isoleucine, valine, asparagine, glutamate, and aspartate) – Leucine and isoleucine can be converted to acetyl CoA, which can yield energy for muscle through the TCA cycle – Carbon skeletons from the other AAs can enter the TCA cycle and have various outcomes • Energy produc.on by running through TCA cycle • From pyruvate, muscle can generate alanine, which is released into the circula.on and can be taken up by liver – Liver can u.lize alanine to make glucose (via gluconeogenesis), which can be released back into the circula.on or stored as liver glycogen
• Alterna.vely, muscle can generate glutamine, which is released into the circula.on and can be taken up by the small intes.ne and other rapidly dividing .ssues for energy
Abbreviation: TCA, tricarboxylic acid cycle. Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman & Co.; 2002. Wagenmakers AJ. Exerc Sport Sci Rev. 1998;26:287-314. 58
Timing of Inges3on and Macronutrient Content of Meals § There is increasing agreement that immediate post-‐exercise inges.on of protein and/or carbohydrate has beneficial effects on – Muscle glycogen replenishment (par.cularly carbohydrate, protein may provide addi.onal benefit) – Muscle protein synthesis (par.cularly protein, carbohydrate may have permissive effect due to insulin release)
§ A combina.on of both protein and carbohydrate seems to work beTer than either carbohydrate or protein alone – Propor.ons of carbohydrate/protein vary based on individual needs • Endurance athletes priori.ze carbohydrate intake for glycogen replenishment • Bodybuilders priori.ze protein intake for muscle growth
Zawadzki KM, et al. J Appl Physiol. 1992;72(5):1854-1859. Ivy JL, et al. J Appl Physiol. 2002;93(4):1337-1344. 59
Protein and Glycogen Replenishment § Rapid post-‐exercise consump.on of carbohydrate and protein in a 3:1 or 2:1 ra.o appears to replenish muscle glycogen to a greater extent than carbohydrate alone – Unclear if this effect enables beTer performance in a subsequent bout of exercise within ~6 hours
§ Protein supplementa.on may exert a stronger replenishment effect when lower post-‐exercise carbohydrate is provided (1.2 g/kg/hr)
Preoccupation with protein intake may be at expense of adequate carbohydrate consumption, resulting in poor glycogen recovery and potential for subsequent performance decrements Ivy JL, et al. J Appl Physiol. 2002;93(4):1337-1344. Berardi et al. Med Sci Sports Exerc. 2006;38(6):1106-1113. Ferguson-Stegall L, et al. J Strength Cond Res. 2011;25(5):1210-1224. Beelen M, et al. Int J Sport Nutr Exerc Metab. 2010;20(6):515-532.
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Progress Check—Determining Protein Recommenda3ons for Athletes 1. There is no need for amino acid supplementa.on as long as complete protein requirements are met. A. B.
True False
2. What is a poten.al risk associated with large, single doses of amino acid supplementa.on? A. B. C. D.
Heart disease Diarrhea Kidney disease Muscle soreness
3. Immediate post-‐exercise inges.on of protein and/or carbohydrate has beneficial effects on: A. B. C. D.
Muscle glycogen replenishment Muscle protein synthesis Muscle phosophocrea.ne levels A and B
61
Progress Check—Determining Protein Recommenda3ons for Athletes 1. There is no need for amino acid supplementa.on as long as complete protein requirements are met.
A. True
Correct, intake over 2.0 g/kg per day has not been shown to increase benefits, and athletes usually take in this amount.
û
B. False
Incorrect, please review slide on Amino Acid Intake Recommenda?ons to be7er understand protein intake and benefit.
62
Progress Check—Determining Protein Recommenda3ons for Athletes 2. What is a poten.al risk associated with large, single doses of amino acid supplementa.on?
û
A. Heart disease
B. Diarrhea
Incorrect, please review slides on Poten?al Risks of AA Supplementa?on to be7er understand poten?al side effects of large, single doses of amino acids as a supplement.
Correct, large, single doses of amino acid supplements may cause diarrhea.
û
C. Kidney disease
Incorrect, please review slides on Poten?al Risks of AA Supplementa?on to be7er understand poten?al side effects of large, single doses of amino acids as a supplement.
û
D. Muscle soreness Incorrect, please review slides on Poten?al Risks of AA Supplementa?on to be7er understand poten?al side effects of large, single doses of amino acids as a supplement.
63
Progress Check—Determining Protein Recommenda3ons for Athletes 3. Immediate post-‐exercise inges.on of protein and/or carbohydrate has beneficial effects on: û
A. Muscle glycogen replenishment
Incorrect, please review slide on Timing of Inges?on and Macronutrient Content of Meals to be7er understand the benefits of correct ?ming of protein intake post-‐exercise.
û
B. Muscle protein synthesis
Incorrect, please review slide on Timing of Inges?on and Macronutrient Content of Meals to be7er understand the benefits of correct ?ming of protein intake post-‐exercise.
û
C. Muscle phosophocrea.ne levels
Incorrect, please review slide on Timing of Inges?on and Macronutrient Content of Meals to be7er understand the benefits of correct ?ming of protein intake post-‐exercise.
D. A and B Correct, both glycogen replenishment and protein synthesis in muscles benefit from immediately inges?ng protein post-‐exercise.
64
Pucng a Meal Plan Together § Example: 70-‐kg athlete requiring 4,000 kcal/day exercising 120 min/day, 4 to 6 .mes/week § Macronutrient Target Recommenda.ons – Grams/kg body weight/day • Carbohydrate 7-‐10 g/kg (490-‐700 g/day) • Protein 1.5-‐2.0 g/kg (105-‐140 g/day) • Fat Typically use percentage of energy – Percentage of energy • Carbohydrate 55-‐65% of energy (550-‐650 g/day) • Protein 10-‐15% of energy (100-‐150 g/day) • Fat 20-‐30% of energy (88-‐133 g/day)
§ Target recommenda.ons for this athlete • Carbohydrate • Protein • Fat
600 g/day (60% of energy) 130 g/day (13% of energy) 120 g/day (27% of energy)
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A Poten3al Distribu3on of Macronutrients Over the Course of 6 Meals/Day
Meal
Time
Carbohydrate, g
Protein, g
Fat, g
Breakfast
7:00 AM
90
15
15
Mid-‐morning snack
10:00 AM
25
10
5
Noon
75
20
20
Pre-‐exercise meal
1:30 -‐ 2:00 PM
90
10
5
During exercise
3:00 -‐ 5:00 PM
100
0
0
Post-‐exercise meal
5:00 PM
75
30
25
Dinner
6:30 PM
120
30
35
Evening snack
9:00 PM
25
15
15
600
130
120
Lunch
TOTALS
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Protein Content of Various Foods 1 egg, 2 egg whites, or ¼ cup egg subs.tute 1 cup of milk ¼ cup coTage cheese 1 cup of yogurt 1 oz. of chicken, fish, pork, or beefa 1 oz. of cheese (except cream cheese) 1 slice of bread or ½ bagel 1 cup of cereal 2 Tablespoons peanut buTer 1/2 to 2/3 cup of dried beans or len.ls 1 cup miso 4 oz. raw, firm tofu ½ cup peas or corn ½ cup of non-‐starchy vegetables 8 oz. soy milk Protein drinks and powders/serving
Protein Content, g 6-‐7 8-‐10 7 8 7 7 3 3-‐6 7 8 8 9 3 2 5-‐6 10-‐45
a3-‐ounce por.on (21 g protein) is the size of the deck of cards.
Pennington JAT, et al. Bowes and Church’s Food Values of Portions Commonly Used. 17th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1998. 67
Summary § Adequate protein intake is cri.cal for athle.c performance and good health § For most athletes, protein intakes of 1.5 to 1.8 g/kg/day (0.68-‐0.81 g/lb/day) will meet protein requirements § High quality protein sources (eg, dairy products, meats, fish, chicken, soy, eggs) should be included in the diet § Ea.ng a combina.on of carbohydrate and protein soon aaer exercise can help with muscle recovery and building
68
Summary (Cont’d) § Research is emerging on poten.al benefits of certain amino acids or amino acid metabolites for athletes – First rule is to get appropriate amount of high quality protein from diet
§ There are several disadvantages of excessive protein intake (ie, well above 2 g/kg/day) – In general, no addi.onal benefit for strength or muscle building – Increased water loss from the body due to disposal of excess nitrogen in urine, which may lead to dehydra.on – May replace carbohydrates and other vital nutrients for athle.c performance and good health
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