NUTR 2050E Exam 2 Notes
How much protein should be consumed after competition
Consuming carbohydrate with the protein may also enhance the anabolic effects after exercise, possibly attributed to increase insulin secretion - Whole foods, such as a turkey breast sandwich, appear to be as effective as amino acid solutions - Carbohydrate: protein ratio 3:1 or 4:1 • Commercial products • Chocolate milk • 6 to 20 grams of high-quality protein - Casein - EAAs - Whey - EAAs and BCAAs - Soy - EAAs • Essential amino acids are key. • Should be consumed within 15-30 min after competition • Hydrolyzed protein sources are absorbed more quickly. • Benefits of CHO and protein: - May enhance protein/CHO uptake into cells • Increase protein synthesis • Increases glycogen synthesis
Quercetin
• A dietary flavonol that functions as an antioxidant • Marketed in some energy drinks • Research: quercetin does not perform as claimed, especially in trained individuals. Findings in untrained individuals were equivocal. • Not recommended as a supplement to improve exercise performance, although data on the prevention of upper respiratory tract infections are promising.
What's the bottom line regarding the ergogenic effects of fat-burning diets or strategies?
• Increasing the use of fat as a fuel during exercise does not appear to increase endurance exercise capacity • Athletes should not attempt to increase the amount of fat in their diet • Recommendations suggest athletes should consume about 20-30% of daily energy needs as fat • High-fat diets may impair exercise performance
Branched Chain Amino Acids (BCAA)
• Leucine, isoleucine, and valine are three major amino acids in muscle tissue • Theoretical ergogenic mechanisms: - Use as a fuel during exercise and spare muscle glycogen - Decrease the rate of muscle tissue degradation - Prevent adverse changes in brain neurotransmitter function
Glucosamine and Chondroitin - Research findings
• Limited research with highly trained individuals; most are with older, arthritic individuals • A substantial number of studies and reviews indicate supplementation reduced joint pain and improved mobility • Large NIH study (GAIT) found no overall reduction in knee pain in osteoarthritic individuals, but the supplement did provide relief to a subset of individuals with moderate to severe knee pain • Beneficial effects were minimal in two studies with younger, physically active males • Glucosamine sulfate appears to be the most effective form; chondroitin is not effective
Fat Intake: During Exercise
• Long-Chain Fatty Acids • Absorption is slow • Benefits questionable • Recommendations: - Avoid fats during exercise
Fat use during exercise
• Low/medium intensity and long duration exercise: - Mild exercise @ 25% VO2max • About 80% or energy may come from fat • Most serum FFA come from the adipose tissue - More intense exercise up to 65% VO2max • Muscle triglycerides become increasingly important • High-intensity exercise ≥ 85% VO2max - Carbohydrate is more important and fat use drops to ≤ 25% as muscle glycogen becomes the main source - In general, FFA oxidation decreases as carbohydrate oxidation increases with increases in exercise intensity
Vitamin Supplements: Ergogenic Aspects
• Many athletes use vitamin supplements • Dietary supplements are marketed to physically-active individuals - Individual vitamins - Multivitamins - Antioxidants - Vitamin-like substances
Bee Pollen
• Marketed specifically to runners - No specific physiological mechanism - Not effective as ergogenic aid - May cause allergic reaction
Excessive intake of vitamins
• RDA for some vitamins now being considered for health promotion • Hypervitaminosis - Not likely to occur from natural foods - Most likely due to excessive intake • Vitamin supplements • Fortified foods • Combination of the two - Vitamins begin to function as drugs - UL has been established for 7 of the 13 essential vitamins
Glutamine Supplementation and Endurance Performance - Main research findings
• Recent studies and reviews indicate that glutamine supplementation will increase plasma glutamine levels but will not - Increase muscle mass or strength - Provide any advantage over adequate carbohydrate on muscle glycogen levels - Prevent the effects of overtraining - Decrease the frequency of respiratory infections
Tyrosine - Main research findings
• Research is very limited • No effect on aerobic endurance, anaerobic power, or muscular strength
A Summary of Protein Digestion and Absorption
- Protein catabolism (break down of proteins) - Amino acids are broken down into: • Nitrogen: excreted as urea • Alpha-ketoacid: -Used as energy -Converted to carbohydrate or fat
Summary of Protein Functions
- Structural function: form vital constituent's of all cells in the body, such as contractile muscle protein - Transportation function: transport various substances in the blood, such as the lipoproteins for conveying triglycerides - Enzyme function: form almost all enzymes in the body to regulate numerous, diverse psychological processes -Hormone and neurotransmitter function: form various hormones, such as insulin; form various neurotransmitters, or neuropeptides, that function in the central nervous system such as serotonin -Immune function: form key components of the immune system, such as antibodies -Acid-base balance function: Buffer acid and alkaline substances int the blood to maintain optimal pH -Fluid balance function: exert osmotic pressure to maintain optimal fluid balance in body tissues, particularly the blood -Energy function: provide source of energy to the Krebs cycle when deaminated; excess protein made be converted to glucose or fat for subsequent energy production - Movement function: provide movement when structural muscle proteins use energy to contract
Fish and Health - Caution Recommended for some
- Women of childbearing age • Limit intake of large, predatory fish • Eat no more than 12 ounces of other fish per week • Limit light tuna to 3 cans, white to1 can per week - Pregnant women should avoid canned tuna entirely - Young children should follow similar precautions - Adults should eat a wide variety of fish; local fish if possible
What are phospholipids?
a lipid containing a phosphate group in its molecule (somewhat similar to triglycerides)
Foods Rich in Vitamins
-Starches and grains: B1, B2, Folate, E -Fruits: B carotene, C -Veggies: B carotene, niacin, b6, folate, c, e, k -Meat/fish/poultry: B1, b2, niacin, b6, b12, folate, a - Milk/dairy: b3, b12, a*, d* -Fats and oils: E * Fortified milk Notes: (1) Vitamin D is synthesized in the skin from sunlight (2) Vitamin K is synthesized in the intestines by bacteria (3) β-carotene may be converted to vitamin A (4) Some foods are fortified with up to 100% of the RDA for vitamins and minerals.
Recommendations for protein intake in athletes
1. Obtain about 15 percent or more of daily energy intake from protein - Some athletes may need more protein than others • Athletes in weight-control sports • Female endurance athletes with low energy intake - Protein intake is within the AMDR 2. Consume protein, preferably with carbohydrate, before and after workouts: The concept of Nutrient Timing. - Consuming protein before exercise is better than after exercise. - Before and after is Best. - The protein source should contain all essential amino acids • About 0.1 gram per kg body weight is recommended • 7 grams for a 70-kg individual 3. Be prudent regarding protein intake. - There is insufficient evidence that increased protein intake will enhance exercise performance - Experts contend that given sufficient energy intake, lean muscle mass may be maintained within a wide range of protein intakes - There is a metabolic rationale for increasing protein intake if muscle hypertrophy is the goal, but the intake need not be excessive and may be within the AMDR of 10-35% of daily energy intake
essential water soluble vitamins
Biotin, Folate, Niacin, Pantothenic Acid, Riboflavin, Thiamin, Vitamin B6, Vitamin B12, Vitamin C
What are the major functions of protein in human nutrition?
Dietary protein serves all three major functions of nutrients - Forms the structural basis for the vast majority of body tissues - Forms numerous enzymes and hormones to help regulate body metabolism - Used as an energy source if needed • A sufficient amount of carbohydrate calories must be present to provide a protein-sparing effect
Omega-3 fatty acids: EPA and DHA Part 2
Experimental research has suggested a number of possible mechanisms underlying health benefits of omega-3 fatty acids - Reduce serum triglycerides - Increase HDL-cholesterol - Prevent clot formation - Decrease platelet aggregation - Improve vascular tone - Decrease blood viscosity - Optimize blood pressure - Promote anti-inflammatory activity - Decrease abnormal heart rhythms
Vitamin D
Food sources - Most foods contain no vitamin D - Fatty fish (salmon, sardines) contain 200-500 IU in 3 oz - Egg yolks contain about 25 IU - Mushrooms, Shiitake; 3 contain about 250 IU - Fortified foods (milk; cereals) may contain 50-100% of RDA Supplements - D2, ergocalciferol; D3, cholecalciferol • D3, cholecalciferol, is the recommended form - Normally contain 200-600 IU - Some contain 5,000 IU Exposure to sunshine - Swimsuit with no sunscreen • 20,000 - 30,000 IU in 30 minutes - Hand, arm and face exposure • RDA with 10-20 minutes in the summer sun • African Americans may need up to 10 X sun exposure to produce similar amounts of vitamin D - Need longer exposure time in the winter • May be difficult to obtain sufficient amounts in northern latitudes
Vitamin K
Food sources: - Plant foods: Vegetable oils; green leafy vegetables • Main dietary source • 3 oz spinach contain 380 mcg - Animal foods: Meats and milk • Lower concentrations • 3 oz meat contain 1 mcg Synthesis in body: - Intestinal bacteria form menoquinone (MK) • Major functions: - Essential in two steps of the blood clotting process - May enhance function of osteocalcin, a protein with an important role in bone formation Supplementation - Effects on exercise performance • No studies have evaluated the ergogenic effects of vitamin K supplementation
Vitamin E
Food sources: - Polyunsaturated vegetable oils; margarine 1 tablespoon contains 3-5 IU - Fortified cereals; wheat germ oil Fortified cereals contain 10-45 IU - Moderate/small amount in meats, dairy, fruits and vegetables • Major function is to serve as an antioxidant - Prevent oxidation of cell phospholipids • Red blood cells • LDL-cholesterol - Prevent oxidation of vitamin A • Supplementation - Effects on exercise performance - Theorized to maintain integrity of RBC and O2 delivery by preventing RBC membrane oxidation - Possible benefits • Altitude (1-3 miles) • High-smog areas - No apparent ergogenic effect at sea level
Vitamin B6
Food sources: - Widely distributed in protein foods - Meat, fish, poultry, whole grains Major functions: - Coenzyme for protein metabolism; 60 enzymes • Tryptophan to niacin • Formation of proteins, such as hemoglobin - Neurotransmitter formation - Glycogenolysis and gluconeogenesis Supplementation - Effects on exercise performance - Physically active individuals may need 1.5 to 2.5 the current RDA to maintain good B6 status - Research suggests supplementation does not affect performance positively or negatively
Vitamin A
Good food sources: - Vitamin A in animal foods; liver, butter, fortified milk - Beta-carotene in dark-green, yellow-orange vegetables; some fruits Major functions in humans: - Maintenance of epithelial cells; Vision - night and peripheral; bone development; immune system; antioxidant
Recommended Protocol
Loading phase: Fast protocol: 20-30 grams/day for 5-7 days Slow protocol: 3 grams/day for 30 days Maintenance phase: 2-5 grams/day Recommended Protocol Creatine Supplementation (20g/day for 5 days) with and without Carbohydrate (360g)
NEXT CHAPTER
PROTIEN
Vitamin A Supplementation
Supplementation - effects on health (beneficial or detrimental): - Not recommended unless under medical guidance; - Hypervitaminosis A: weakness, nausea, headache, joint pain, skin peeling; may lead to bone loss; hip fractures; liver damage; in pregnancy excess A may be teratogenic - Beta-carotene; harmless yellowing of skin in excess - Note: Antioxidant effects on health covered later in chapter Supplementation - effects on sport (beneficial or detrimental): - Little theoretical value; no beneficial effect - Note: Antioxidant effects of beta-carotene on exercise performance and prevention of muscle tissue damage covered later in the chapter
CHAPTER 7
VITAMINS
essential fat soluble vitamins
Vitamin A Vitamin D Vitamin E Vitamin K
What are vitamins and how do they work?
Vitamins - Major Functions • Coenzyme Functions B vitamins • Antioxidant Functions Beta-Carotene (Vitamin A) Vitamin C Vitamin E • Hormone Functions Vitamin D
What are vitamins and how do they work? pt 2
Vitamins - Major Functions • Most B vitamins function as coenzymes (an activator of an enzyme) • Thus, B-vitamins do NOT give you energy, rather, they assist in chemical reactions that can result in energy production in the form of ATP
Can the body make fat from protein and carbohydrate?
Yes
non-essential amino acids
alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, tyrosine
essentail amino acids
histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
Types of fatty acids
saturated, monounsaturated, polyunsaturated
What is fat loading?
theoretical mechanism to help delay onset of fatigue - Elevated serum FFA levels and muscle triglyceride levels - Increase the percentage use of fat as an energy source during exercise - Spare the use of muscle glycogen
Vitamin Supplementation: Key Points
• A vitamin deficiency can impair physical performance • Correcting a vitamin deficiency returns performance to normal • In general, supplementation to an athlete on a well-balanced diet does not enhance performance • Obtaining adequate amounts of the antioxidant vitamins via a healthful diet may benefit some athletes - Additional research appears to be warranted: • Vitamin E and endurance at high altitude • Antioxidants and prevention of muscle catabolism; older athletes • Some endurance athletes may need vitamin supplements - Weight-loss dieting - Females of childbearing age - Older athletes - Vegans who do not consume fortified foods (B12) - Poor dietary habits
How does dietary fat get into the body?
• About 98 percent of dietary fat consists of triglycerides • Bile salts and lipases digest dietary lipids into free fatty acids (FFA), glycerol, cholesterol, and phospholipids • Absorbed into intestinal cell; form a chylomicron, which enters the lymphatic system • Some fatty acids (medium chain triglycerides) go directly to the liver
How much protein do I need?
• Acceptable Macronutrient Distribution Rate (AMDR): - 10-35% of daily energy intake OR • Recommended Dietary Allowance (RDA) - 0.8g/kg of body wt. • Adult Female - 132 lbs (60 kg) - 2,000 Calorie diet • RDA is 48 grams of protein (60 x 0.8) • AMDR of 10% provides 50 grams of protein - 2,000 x 0.10 = 200 protein Calories - 200/4 Calories per gram of protein = 50 grams of protein
Acute fat loading
• Acute high-fat diets - Infuse a lipid solution, with heparin - Ingest a high-fat (60-90% fat) meal prior to exercise - Ingest a high-fat diet for 1-2 days prior to exercise • Research findings - Acute high fat diets do not enhance aerobic endurance performance - Some research indicates consuming a high-fat diet for 1-2 days may impair performance in high-intensity exercise tasks
Dietary protein needs: Strength-type activities
• Additional protein is often recommended to help support or promote increases in muscle tissue • Some exercise scientists recommend an optimal intake of about 1.5 to 1.8 grams/kg body weight
What are triglycerides?
• An ester of glycerol (alcohol) and 3 fatty acids
Beta-alanine and Carnosine - Main research findings
• Anserine supplementation increases muscle carnosine • Possible ergogenic effects on anaerobic-type exercise performance - Improved performance cycling @ 110% VO2max - Enhanced sprint performance at the end of an exhaustive exercise bout • No ergogenic effect on aerobic-endurance - No effect on maximal aerobic power
Are amino acid, amine, and related nitrogencontaining supplements effective ergogenic aids?
• Arginine and Citrulline • Arginine, Lysine, and Ornithine • Tryptophan • BCAA • Glutamine • Glycine • Glucosamine and Chondroitin • Creatine • HMB • Beta-alanine and Carnosine • Tyrosine • Inosine
Arginine and Citrulline - Main research findings
• Arginine is a precursor for NO • May improve exercise ability in cardiac patients - Research does not support an ergogenic effect with healthy individuals, and arginine may be ergolytic • Increased RPE values • Decreased time to exhaustion
Essential vitamins
• Cannot be synthesized in the body in sufficient quantity • Causes deficiency symptoms when intake is inadequate • Alleviates deficiency symptoms when added back into the diet • Some substances, such as CoQ10, have been attributed with vitamin-like activity, but are not essential vitamins
Protein use and importance of carbohydrate
• Carbohydrate availability is an important factor affecting the use of protein as an energy source during aerobic endurance exercise • Research indicates that elevated endogenous stores of carbohydrate or provision or exogenous carbohydrate during exercise may exert a protein sparing effect
Dietary protein needs: Endurance-type activities
• Carbohydrate is the main fuel for endurance type athletes • More dietary protein is recommended to - Restore protein used for energy - Promote synthesis of oxidative enzymes and mitochondria - Help prevent sports anemia • Some exercise scientists recommend an optimal intake of about 1.1 to 1.4 grams/kg body weight for aerobic endurance athletes, and 1.4 to 1.7 grams/kg body weight for intermittent high-intensity sports • The NAS indicates that the RDA is sufficient
Vitamin/mineral supplements
• Check the Daily Value; look for 100% of DV • Be leery of some bargain brands, such as those in dollar stores • Stick with the basics; 11 vitamins and 7 minerals
What is cholesterol and what foods contain cholesterol?
• Cholesterol is not a fat, but a sterol • Cholesterol is not an essential nutrient, essential meaning necessary in the diet • Cholesterol may be manufactured in the liver
What effect does exercise training have upon protein metabolism?
• Chronic exercise training appears to decrease protein catabolism during standardized exercise tasks • Aerobic endurance training appears to increase the ability of the muscle to use protein as an energy source, if needed. - May help preserve glucose for the brain when carbohydrate levels are low
Chronic fat loading
• Chronic high-fat diets - Ingest a high-fat (40-70%) diet for 1-3 weeks - Some studies provided high-carbohydrate meals prior to testing • Research findings from studies and reviews with trained individuals • It appears that there are responders and non- responders
What happens to the lipid once it gets into the body?
• Circulate in the body as chylomicrons • Lipids deposited in body cells for storage as triglycerides - Fat or adipose cells - Muscle cells (IMTG - Intramyocellular triacylglycerol) • Liver continues to modify the composition of the lipoproteins
CoQ10
• Coenzyme Q10 (CoQ10) - A lipid with characteristics of a vitamin - Involved in oxidative processes; serves as an antioxidant - Used in treatment of cardiovascular disease - Use as an as ergogenic aid • Studies cited in a book show ergogenic effects • Most well-controlled studies show no effects - VO2max, exercise time to exhaustion, muscle tissue damage - May cause muscle tissue damage; pro-oxidant - The majority of research studies suggest that CoQ10 is not an effective ergogenic aid, and thus, is not recommended as a supplement for physically active individuals
Glycine - Main research findings
• Contemporary research reveals no ergogenic effect of glycine supplementation • Glycine is part of a multicomponent supplement containing arginine and alpha-ketoisocaproic acid that has been found to enhance sprint power in one study. Additional research is needed for confirmation.
Creatine
• Creatine is found naturally in animal foods, especially meat • Creatine may also be synthesized by the liver and kidney Milk: 0.1 g/kg Tuna: 4.0 Salom: 4.5 Beef: 4.5 Pork: 5.0
Arginine, Lysine, and Ornithine -Main research findings:
• Early, poorly controlled research found ergogenic effects • More recent well controlled studies report - No significant increases in Human Growth Hormone (HGH) - No favorable changes in body composition - No increases in strength
Omega-3 fatty acids: AHA Scientific Statement Key Points
• Eat fish, particularly fatty fish, at least twice a week • Eat plant foods rich in alpha-linolenic fatty acid • Individuals who have high serum triglycerides may benefit from a fish oil supplement of 2-4 grams of EPA and DHA daily
High-protein diets and aerobic endurance: Protein/Carbohydrate Preparations
• Effects on recovery from exercise - Recent studies find that when energy content is balanced, protein/carbohydrate solutions provide no advantage over carbohydrate alone on subsequent exercise performance - Some data suggest protein/carbohydrate solutions may prevent muscle soreness, while other research does not
Fats and Endurance Performance
• Endurance training induces adaptations that enhance fat utilization and aerobic exercise performance - Increased expression of genes in the skeletal muscle that increase enzymic capacity for fat oxidation - Increased muscle triglyceride storage • Increased insulin sensitivity facilitates FFA entry to muscle • Increased FFA transporters in the muscle cell membrane - Increased sensitivity of muscle and adipose cells to epinephrine - Increased transport of plasma FFA into muscle during exercise
Omega-3 fatty acids: EPA and DHA
• Epidemiological research indicates populations that consume diets rich in fish have a lower incidence rate of Coronary Heart Disease • Theory underlying health effects of EPA and DHA - Help to form eicosanoids (local hormones) that affect metabolism and gene expression
Can the antioxidant vitamins prevent fatigue or muscle damage during training?
• Exercise training may increase total antioxidant capacity - Superoxide dismutase and glutathione peroxidase (enzymes that helps neutralize free radicals) - Such adaptations provide protection against free radical damage • Antioxidants not shown to improve exercise performance - Individual antioxidants - Antioxidant cocktails
Omega-3 fatty acids: EPA and DHA Part 3
• Experimental research findings are equivocal regarding a cardio protective effect of omega-3 fatty acid supplementation • Some reviews note that epidemiological evidence favors risk reduction, while experimental studies do not. People who eat more fish may engage in other healthy behaviors • Conversely, several meta-analyses indicate eating more fish and omega-3 fatty acids lowers mortality from cardiovascular disease
Will fasting help improve my performance?
• Fasting for 24 hours may increase serum FFA availability • However, fasting may impair - Carbohydrate availability - Endurance exercise performance • Fasting may be used in weight-control sports, and effects are discussed in chapter 10
Fat Intake: Before Exercise
• Fat Adaptation - Short-term - Long-term • Single High-Fat PreCompetition Meal • Recommendations - Include fats but keep to a minimum - Experiment with different fat content
Are fats used as an energy source during exercise?
• Fat energy sources during low intensity and long duration exercise: - Adipose cell triglycerides • Hormone-sensitive lipase released FFA • Increases serum FFA for delivery to muscle - Muscle cell triglycerides • Muscle lipoprotein lipase releases FFA • Use during exercise - Serum FFA into muscles is increased during exercise - Epinephrine stimulates FFA release from muscle triglycerides
How much total energy is stored in the body as fat?
• Fat is an efficient form of energy storage - 9 Calories per gram - Very little water content • Total amount of stored fat energy varies, but approximately 80,000 to 100,000 Calories in the average adult male with normal body fat • Most fat is stored in the adipose cells; but there are also some stores in the muscle and liver
Fat as an energy source
• Fat produces energy only by aerobic processes • Fat provides about 60% or energy at rest • Triglycerides yield - Glycerol, which goes to the liver - FFA, which may be oxidized for energy • Ketones - By-products of excess fatty acid metabolism • Or not enough carbohydrates for energy - May be used for energy in cells
Tryptophan - Main research findings:
• Findings from studies are somewhat equivocal • In general, results suggest that tryptophan supplementation is not an effective ergogenic aid for either strength or aerobic endurance exercise
Creatine Supplementation
• Findings may be applicable to sports such as weightlifting, cycle, swim and run sprints, and soccer • In general, research findings also indicate that creatine supplementation may enhance performance in very high-intensity exercise tasks, such as the 100- meter sprint in track and sprint cycling
Fat Intake: After Exercise
• First post-exercise meal: - Keep fat intake low - Focus on getting carbs and small amounts of protein • Rest of day: Normal dietary recommendations for fats apply - 20-35% fat content - Unsaturated fats
How much protein should be consumed 1 to 4 hours before competition?
• Focus should be on CHO • Small amounts of protein good (i.e., 2-4 oz lean meat) • Lean protein sources preferable
Pantothenic acid (B5)
• Food sources - Distributed widely in all natural animal and plant foods - Major losses in highly processed foods • Major functions: - An essential component of coenzyme A - Acetyl CoA from carbohydrate, fat and protein • Supplementation - Health and exercise performance - Current research indicates that supplementation with pantothenic acid has no ergogenic effect on various tests of aerobic endurance performance in runners and cyclists
Biotin
• Food sources - Organ meats, egg yolk, legumes, green leafy vegetables - Also synthesized in the intestines by bacteria • Major functions: - Coenzyme for enzymes involved in protein metabolism - Involved in gene expression - Involved in gluconeogenesis - Involved in the synthesis of glucose and fatty acids • Supplementation - Health and exercise performance - No evidence that biotin supplementation enhances health or exercise performance is available
Niacin (B3)
• Food sources: - Foods with high protein content - Meat, fish, poultry, whole grains, legumes • Major functions: - Coenzymes for glycolysis and fat synthesis • Important for both aerobic and anaerobic energy processes Supplementation - Effects on health - May cause flushing, burning and tingling sensation - High doses may improve serum lipid profile • Reduce total and LDL-cholesterol and triglycerides • Increase HDL-cholesterol - Excess may cause liver damage - Use only under medical care Supplementation - Effects on exercise performance - Several studies report no ergogenic effect • 10-mile run • Prolonged cycling - Not recommended • May impair endurance performance by interfering with fat metabolism during exercise
Folate
• Food sources: - Green, leafy vegetables, like spinach - Whole grains, legumes - Fruits and vegetables - Fortified grains (140 mcg/100 grams of food) • Major functions: - Coenzyme critical to formation of DNA - Needed during periods of rapid cell division • Red blood cell formation • Early pregnancy • Supplementation - Effects on health - May help prevent neural tube defects (NTD) - Food fortification studies • ↓ incidence of NTD up to 78% - All women of childbearing age should obtain 400 mcg as folic acid, plus food folate • Supplementation - Effects on physical performance - No apparent effect on endurance performance - Folate supplementation may increase serum folate, but has no effect on hemoglobin, VO2max, or endurance running time
Vitamin B12
• Food sources: - Only found in animal foods; meat, fish, poultry, milk - Vegans need fortified food source or supplement - Found in fortified foods, such as breakfast cereals Major functions: - Part of coenzyme critical to formation of DNA; works with folate - Red blood cell formation - Formation of myelin sheath on nerve fibers • Supplementation - Effects on health - May help treat pernicious anemia - No apparent adverse effects of large doses • Supplementation - Effects on exercise performance - No apparent effect on endurance performance
Riboflavin (B2)
• Food sources: - Widely distributed in plants and animal foods - Milk, dairy products, whole wheat • Major functions: - Needed for oxidative enzymes - flavoproteins - Important for carbohydrate, fat and protein metabolism - Healthy skin tissue • Supplementation: Effects on health - Has no health benefits for well-nourished individuals - No UL has been set for riboflavin • Supplementation: Effects on exercise performance - Only one reputable study conducted and reported no beneficial effects on performance
Thiamin
• Food sources: - Widely distributed in plants and animal foods - Whole wheat, pork - Fortified cereals contain 100% of RDA • Major functions: - Energy substrate coenzyme for carbohydrate • Needed to convert pyruvate to acetyl-CoA • Normal functioning of the nervous system • Supplementation: Effects on health - No benefits to well nourished individuals - No UL has been established for thiamin • Supplementation: Effects on exercise performance - No beneficial effects on performance - Thiamine derivatives, allithiamine: no ergogenic effects
Incomplete Protein
• Foods that are low (or missing) one or more essential amino acids • Plant proteins • An essential amino acid that is in limited supply in a particular food is a limiting amino acid - Legumes (methionine) Grains (Lysine)
What are some dietary guidelines to ensure adequate protein intake?
• For omnivorous individuals - Eat a wide variety of animal and plant foods - Select animal foods low in fat - Eat animal foods with plant foods • 70% from plant foods; 30% from animal foods • For vegans - Ensure consumption of adequate amounts of complementary protein foods
Free Radicals
• Free radicals are produced during normal metabolic processes and are involved in normal cell functioning, but may be produced in excess under certain circumstances and be damaging to cellular constituents • Antioxidants neutralize free radicals by donating extra electron to make the pair OR by breaking down the free radical molecule to render it harmless
Formation of carbohydrate and fat from excess protein Part 2
• Glucogenic amino acids - 14 glucogenic amino acids • Ketogenic amino acids - Only leucine and lysine • Glucogenic and ketogenic amino acids - 5 amino acids can be both glucogenic and ketogenic - Isoleucine, phenylalanine
One pound of muscle mass
• Goal: To gain one pound of muscle mass per week in an adult athlete (70 kg) whose protein RDA is about 56 g/day - 1 pound of muscle = 454 grams - Muscle is 22% protein - 454 x 0.22 = 100 grams of protein in 1 pound - 100 grams/7 days = about 14 grams of protein/day - May use 20 grams of protein during exercise - Protein needs • 56 + 14 + 20 = 90 grams of protein/day • 90 g/70 kg = 1.29 grams of protein/day
Do high-protein diets or protein supplements improve aerobic endurance performance in endurance-trained individuals?
• High-protein diets or meals - The Zone Diet (40:30:30), a high-protein diet, has been advocated for endurance athletes - Studies do not support an ergogenic effect of high-protein diets on aerobic endurance - Several studies suggest that a Zone Diet eating plan over the course of a week may actually impair aerobic endurance performance, particularly if protein replaces carbohydrate in the diet
Complete Proteins
• High-quality proteins • Foods that contain an adequate content of all 20 essential amino acids • Animal proteins are this type • Some plant proteins: quinoa, soy
Creatine Supplementation: Effect on body mass
• In general, research indicates increases in body mass, mainly as muscle tissue, in both males and females, including both trained and untrained
Ergogenic effect of carnitine supplementation: Research findings
• May increase plasma levels, but not muscle concentration of carnitine • No effect on fat oxidation • Acute supplementation does not ↑ performance • No effect on lactic acid energy system or related performance • No effect on VO2max or aerobic performance • Does not reduce body fat • L-carnitine is safe, but D-carnitine may be toxic • L-carnitine may improve exercise performance and recovery for those with specific disorders: - Congestive heart failure, peripheral artery disease, chronic stable angina, and chronic obstructive disease
BCAA and the Central Fatigue Hypothesis - Main research findings:
• Mental performance: Results of field studies are equivocal, but several have found enhanced mental alertness in prolonged sport events, such as tennis and soccer • Perceived exertion: Results of laboratory studies involving intense endurance exercise are equivocal. Physical performance with acute supplementation - Study with 193 marathon runners suggested improved performance in slower runners (3:05-3:30) but not faster runners (<3:05) when consuming 7-12 grams during running - Slower runners may have depleted muscle glycogen earlier and thus benefited more from supplementation • Physical performance with acute supplementation: Most well-controlled laboratory and field studies have reported no significant effects on exercise performance
If I want to take a vitamin-mineral supplement, what are some prudent guidelines?
• Most health professionals recommend against single vitamins • A basic one-a-day multivitamin/mineral tablet may be recommended • The ADA recommends low levels that do not exceed the RDA or AI
Vitamin D Functions
• Most tissues and cells in the body have receptors for the hormonal form of vitamin D, and 200 and 2,000 genes are controlled by vitamin D. • Central role in bone metabolism through its effect on calcium and phosphorus • Works in conjunction with several other hormones, particularly parathormone secreted by the parathyroid gland. • Helps to absorb calcium from the intestinal tract and the kidneys, helping to maintain normal serum calcium levels and proper bone metabolism. • Helps regulate phosphorus metabolism, another mineral essential in bone formation.
Multivitamin-mineral supplements
• Multivitamin-mineral supplementation (100-6000% of the RDA) has not been shown to enhance VO2max and aerobic capacity, as well as laboratory and field tests of anaerobic and aerobic endurance, such as 400-meter and 15K run performance, in elite athletes. • Some athletes may be advised to take a simple one-a-day multivitamin-mineral
How effective are the special supplements marketed for athletes?
• Multivitamin-mineral supplements • Bee pollen • CoQ10 • Quercetin
Water-Soluble Vitamins
• Nine vitamins - B complex (8 individual vitamins) - Vitamin C • Deficiency symptoms may be noted in 2-4 weeks for some B vitamins - May impair energy production for exercise
Dietary Nitrate
• Nitrate is found in all vegetables, particularly leafy greens and beetroot • Potential cardiovascular benefits
Ergogenic effects of MCTs: Research findings
• No enhanced performance in endurance exercise tests - MCT supplementation - MCT supplementation combined with carbohydrate • Does not appear to spare use of muscle glycogen • Impaired performance with MCT supplementation • May also cause gastric distress in some individuals
Omega-3 fatty acids
• Omega-3 fatty acids - Eicosapentaenoic acid (EPA) - Docosahexaenoic acid (DHA) • Found mainly in fish
Taurine - Main research findings
• One study demonstrated an increased fat oxidation during 90 minutes of cycling @ 66% VO2max • One study reported ↑ VO2max and exercise time to exhaustion associated with antioxidant effects • These preliminary findings need further research
Dietary Nitrate - Research Findings
• One study demonstrated improved performance in 4 km & 16.1 km time trials with club-level competitive cyclists when supplemented with beetroot juice vs. a placebo • Reduced systolic and diastolic blood pressures have been seen during 15 days of supplementation • One study found a reduced oxygen cost of moderate intensity exercise • The potential reduction in oxygen cost associated with nitrate supplementation may be of particular benefit to those with cardiovascular, respiratory or metabolic disorders • These preliminary findings need further research
Chronic High Fat Diets - The Bottom Line
• Overall, research findings are equivocal but generally indicate that a chronic high-fat diet does not enhance aerobic endurance performance • Endurance performance can, at best, only be maintained on such diets as compared to high carbohydrate diets • Endurance athletes may adapt to high-fat diets, but training becomes more psychologically stressful • May impair endurance performance • May impair cognitive function • Diets containing 20-30 percent of energy from fat appear to be reasonable for endurance athletes
Proteins and Endurance Performance
• Protein Use as Energy Source - During rest • <5% of total daily expenditure • Endurance training may reduce protein oxidation at rest, increasing the amount of energy derived from fat
Protein and Amino acids
• Protein is a complex structure containing carbon, hydrogen, oxygen, and nitrogen, and in some cases sulfur. • Amino Acids - Building blocks of protein • Each has - an amino group (NH2) - an acid group (COOH) - a unique side chain
Dietary Protein
• Protein is one of our most important essential nutrients - Structure of body tissues (such as muscle) - Formation of enzymes - May provide small amounts of energy • Implications for sports - Protein needs of strength and endurance athletes
Formation of carbohydrate and fat from excess protein
• Proteins can not be stored as proteins in the body • Glucogenic amino acids - Form pyruvate - Gluconeogenesis (making new glucose from amino acids) • Ketogenic amino acids - Form acetyl CoA fatty acid synthesis • It is important to note that dietary protein and carbohydrate intake will be stored as fat in the body if not needed for other bodily functions
Can the use of medium-chain triglycerides(MCT) improve endurance performance?
• Theory as an ergogenic aid - Rapid absorption into portal circulation - Rapid uptake by mitochondria in muscle cells - May be oxidized at a rate similar to exogenous glucose
Protein use during exercise
• Resistance exercise training - Does not appear to increase protein oxidation - May provoke muscle tissue catabolism (breaking down proteins) - Both catabolism and anabolism (building proteins) may occur during recovery, with anabolism prevailing over time Aerobic endurance exercise training - Protein use is minimal compared to carbohydrate and fat - Dynamic exercise activates BCAA dehydrogenase, an enzyme that oxidizes BCAA - Some amino acids are used to promote gluconeogenesis - Protein use may increase when body carbohydrates stores decrease • Leucine and the Glucose-Alanine Cycle - Leucine is the major BCAA to be oxidized during exercise - The alpha-ketoacid may enter the Krebs cycle - The amino group combines with pyruvate to form alanine, which may be transported to the liver to form glucose - Estimated glucose generation from alanine is very limited
What foods contain phospholipids?
• Rich in eggs, liver, wheat germ, peanuts and other fat containing foods • Not an essential nutrient • Can be made from triglycerides
What's the bottom line regarding vitamin supplements for athletes?
• Some athletes may need supplements; however, if eating a healthy diet, supplements usually not necessary. • Some health professionals recommend a one-a-day multivitamin-mineral
Fish oil supplements
• Some health professionals recommend 500-1,300 mg daily of EPA and DHA combined, but mainly from fish • American Heart Association - Recommends individuals with heart disease obtain EPA and DHA from fish, about one gram a day - Consult with your physician if you want to obtain EPA and DHA from supplements • Typical 1,000 mg fish capsule contains 300 mg of EPA (180 mg) and DHA (120 MG) • Quality and safety of supplements may be questionable
Should physically active individuals take vitamin supplements?
• Some possible reasons - Weight-control sports - Poor dietary habits - Pregnancy - Elderly, senior athletes - Consult with your health professional
Choline
• Sources: - Animal foods as lecithin; plants as free choline • Egg yolks a great source • Major functions: - Precursor for lecithin; formation of acetylcholine • Supplementation -- Health - Not apparently beneficial, as deficiency is rare - Excess may cause GI distress, low blood pressure • Supplementation - Physical Performance - Preliminary studies have shown supplementation will ↑ serum choline - Preliminary field and laboratory studies found an ergogenic effect - More recent studies reveal no ergogenic effect on endurance performance
Vitamin C
• Sources: - Fruits and vegetables; citrus fruits - One orange or glass of orange juice contains the RDA • Major functions: - Synthesis of collagen - Formation of hormones and neurotransmitters; - Helps absorb iron (non-heme iron) • Non-heme iron is a type of iron that is mainly found in plant food sources vs. heme-iron is the type of iron that is found in animal products - RBC formation - Functions as an antioxidant • Supplementation -- Health - Antioxidant effects discussed later - Controversial opinions on safety of megadoses • Undesirable side effects - Diarrhea - ↓ bioavailability of B6, B12, copper - ↑ urinary calcium oxalates (short-term studies with 1,000 mg) » Possible kidney stones - Iron storage; oxidative effect of iron - Rebound scurvy • No adverse side effects - Excess amounts are excreted by the kidneys - Long term study shows no increase in kidney stones • Supplementation - Exercise performance - Antioxidant effects discussed later - Early research indicates improvement in individuals who are vitamin-C deficient - Some studies indicate reduced severity of upper respiratory tract infections (URTI) following ultraendurance exercise - Current research shows no benefit to immune system functions after endurance exercise - No apparent effect on exercise performance
Fats: Ergogenic Aspects
• Strategies or supplements proposed to be ergogenic - Fat loading - Fasting - Medium-chain triglycerides (MCTs) - Carnitine - Hydroxycitrate (HCA) - Conjugated linoleic acid (CLA)
Antioxidants: Muscle damage during training
• Strenuous exercise may generate reactive oxygen species (ROS) to overwhelm the body' natural antioxidant defense system • Equivocal research and review findings relative to the effects of antioxidant supplementation - Some studies show reduction in markers of muscle tissue damage - Other studies show no benefits - Several studies found adverse effects of supplements - Some suggest older athletes may benefit • Most scientists recommend - More research is needed - Athletes obtain antioxidant from natural foods
Vitamin D supplementation
• Supplementation - Effects on exercise performance - Research is very limited, only a few studies • No ergogenic effects of single megadose • No ergogenic effects of supplementation over the course of 2 years - Little is known of the vitamin D status of athletes
Beta-Hydroxy-Beta-Methylbutyrate (HMB)
• Targeted to strength athletes - why? - HMB is the breakdown product of leucine - Leucine is an important regulator of protein synthesis and breakdown • Main research findings with strength-trained athletes - Findings are equivocal regarding the ergogenic effect of HMB supplementation on muscle mass and strength in untrained individual - HMB supplementation does not appear to affect muscle strength, body composition, or anaerobic exercise performance in resistance-trained individuals - Research does not support any protective effects against muscle tissue damage during resistance training • Main research findings with endurance athletes - One study with distance runners reported HMB supplementation (3 g/day for 6 months) decreased markers of muscle damage following a 20K run - One study found HMB could increase VO2max during 5 weeks of interval training in active college students - No studies have shown improvement in endurance exercise performance following HMB supplementation
Can hydroxycitrate (HCA) enhance endurance performance?
• Theory as an ergogenic aid - Modify citric acid cycle (Kreb's cycle) metabolism to promote fatty acid oxidation • Research findings - Available research is limited, but findings indicate no effect on fat metabolism during exercise in either sedentary or endurance-trained cyclists • Theory as an ergogenic aid - Marketed as a means to decrease body fat and increase lean muscle mass in resistance-trained athletes • Research findings - Research with trained athletes is limited, but indicates CLA supplementation has no effect body fat, muscle mass, or strength tests in resistance-trained athletes - Adverse effects are mild; gastro-intestinal distress most common - Effects on health are discussed later in this chapter
Can carnitine supplements enhance fat metabolism and exercise performance?
• Theory as an ergogenic aid • L-carnitine may help increase a specific enzyme that facilitates transport of long-chain fatty acids into mitochondria and increase fat oxidation • Carnitine may also increase blood flow • may be beneficial to endurance athletes by increasing fat oxidation and sparing muscle glycogen • increased endurance in patients with peripheral vascular disease • marketed for weight loss • Carnitine may facilitate the oxidation of pyruvate, which may reduce production of lactic acid during exercise
Protein: Ergogenic Aspects
• Three of the top 5 most popular sport supplements - Protein - Amino acids - Creatine
Dietary fat: Dietary Reference Intakes
• Total fat - An AMDR of 20-35% of daily energy intake • Saturated fatty acids and trans fatty acids - Health professionals recommend maximum of 7-10% of daily energy needs • Monounsaturated fatty acids - Some health professionals suggest these are good fats - ~10% from total daily calories • Polyunsaturated fatty acids - ~10% from total daily calories - Essential fatty acids: • Omega-6 fatty acids (linoleic acid): 17 g for males and 12g for females • Omega-3 fatty acids (linolenic acid) is an essential fatty acid (1.6 g for males and 1.1 for females • Cholesterol - Little need for us to obtain any from the diet (since body manufactures it )
Exercise training and protein
• Training may decrease the formation of ammonia during standardized exercise - Ammonia is thought to contribute to fatigue, possibly by impairing muscle cell metabolism
What are the different types of dietary fats?
• Triglycerides • Cholesterol • Phospholipids
Essential vs. Non-essential Amino Acids
• Two main classes of amino acids - Essential (indispensable) amino acids • Must be obtained from foods in the diet - Nonessential (dispensable) amino acids • May be formed in the body
What are the different types of lipoproteins?
• Very low-density lipoproteins - Mainly triglycerides; deliver FFA and glycerol to cells • Low-density lipoproteins - Mainly cholesterol; delivers cholesterol to cells - Small dense LDL of health concern • High-density lipoproteins - Mainly protein; delivers cholesterol from cells to liver • Lipoprotein (a) - Similar to LDL; high density range
Fat-Soluble Vitamins
• Vitamins A, D, E, and K • Soluble in fat, but not in water • Found in foods with some fat content • Several may be manufactured in the body • Excessive intake of several may be toxic • Easily stored by the body
What vitamins are essential to human nutrition?
• Water-soluble vitamins - Thiamin - Riboflavin - Niacin - Vitamin B6 - Vitamin B12 - Folate - Biotin - Pantothenic acid - Choline* - Vitamin C • Fat-soluble vitamins - Vitamin A - Vitamin D - Vitamin E - Vitamin K * Not classified as a vitamin
How much fat and cholesterol do we need in the diet?
• We need fat for three reasons - To provide energy needs - To provide essential fatty acids - To provide essential fat-soluble vitamins
Inosine -Main research findings
• Well-controlled studies indicate inosine supplementation - Does not increase VO2max or related physiological variables - Does not improve 3-mile treadmill run time - Has no effect on cycling tests of the three energy systems - May impair anaerobic energy production