MIDTERM 1 Flashcards
Sex differences in carb utilization in athletes
Women oxidize more lipid and less carbohydrate as metabolic substrates than men
Primary role of glucose in the body
- Energy source
- Affects metabolic mixture and spares protein
- Metabolic primer and prevents ketosis
- CNS fuel
Glycogen and where it is stored
Stored in the muscles and liver; synthesized from glucose during glycogenesis
Complex carbohydrate
AKA dietary starch
High carb diet promotes…
more glycogen storage
DRIs for fiber
Male: 38 g/day
Female: 25 g/day
Adequate carb in the diet spares….
Protein
Provide branch chain amino acids that can be used as energy for the muscles
Deamination
Fast protein
Whey (milk protein)
Slow protein
Casein
Nitrogen intake exceeds excretion, additional protein used to synthesize new tissues
Positive nitrogen balance
Nitrogen intake is less than excretion; indicates protein is being used for energy and encroachment on amino acid reserves; reduces body’s lean tissue mass
Negative nitrogen balance
Animal protein sources
Higher quality protein; have a higher biologic value
A food’s protein rating that refers to its completeness for supplying amino acids
Biologic value
Our body can manufacture these amino acids and they are formed from already existing compounds
12 Non-essential amino acids
9 Essential amino acids
Histidine,
Leucine,
Lysine,
Isoleucine,
Methionine,
Phenylalanine,
Threonine,
Tryptophan,
Valine
Significance of Leucine
- the leucine trigger turns on muscle making machinery
- the essential AA that our body needs the most of per day
AMDR for fat
20-35% of total calories
A glycerol base with 3 fatty acid chains; 95% of the fats in our diets
Triglyceride
Lipid kcal/gram
9.4 kcal/gram
Order of GI tract
mouth, esophagus, stomach, small intestine, large intestine, anus
When do we rely on carbs for energy?
As intensity increases
What is the RQ (respiratory quotient)?
RQ = CO2 produced/O2 consumed
When does the respiratory quotient exceed 1?
When a person starts tapping into anaerobic metabolism
Partition nutrients used RQ
1.00 carbs
0.70 fats
0.82 proteins
Blood vessel that carries nutrient rich blood to the liver from intestines, spleen, pancreas, and gallbladder
Hepatic portal vein
Glycolysis
Glucose is split into 2 pyruvate, producing 2 net ATP
Ring of muscle surrounding and serving to guard or close an opening or tube
Sphincter
Aerobic means…
oxygen demand
Fats are converted into acetyl-CoA (and then can enter citric acid cycle/aerobic metabolism)
Beta-oxidation
Creatinine phosphate is used to reconstitute ATP after it is broken down to release its energy
ATP-PC system
Citric acid cycle, oxidative phosphorylation (in mitochondria)
Aerobic systems
Glycolysis (in cytoplasm)
Anaerobic system
Purpose of villi in GI tract
Increase surface area for maximum nutrient absorption
Where is heme iron in our food
Primarily found in animal products; 10-35% absorption by intestines (more absorbable than plant-based iron)
Factors that affect bioavailability of minerals
Type of food, mineral-mineral interaction, vitamin-mineral interaction, fiber-mineral interaction
High fiber intake blunts some mineral absorption (calcium, iron, magnesium, phosphorus) by binding to the minerals
Fiber-mineral interaction
Vitamin D in excess
precipitate excessive calcium deposits and increase kidney and heart damage risk
Vitamin A in excess
hypervitaminosis in children: NS irritability, bone swelling, weight loss, dry itchy skin
In adults: nausea, headache, drowsiness, hair loss, diarrhea, bone calcium loss
Minerals as metabolic cofactors
regulate metabolism by becoming constituents of enzymes/hormones that modulate cellular activity
Role of Vitamin D
Acts as a hormone for many bodily functions: bone health, calcium absorption, muscle function, tissue receptors
Vitamins as co-enzymes
the Water-soluble vitamins
Riboflavin, thiamine, folic acid
Fat-soluble vitamins
A, D, E and K
Osteoporosis in women
white/asian woman is a risk factor for osteoporosis
Female triad
Begins with low energy availability, leads to amenorrhea and potentially osteoporosis
Why are vitamins/minerals essential, antioxidant nutrients?
Our body cannot make them
Antioxidant vitamins
B, C, E, and beta carotene
Average daily nutrient intake sufficient to meet the requirement of 97-98% of healthy individuals in a life stage and gender group
Recommended Dietary Allowance (RDA)
Provides an assumed adequate nutritional goal when no RDA exists
Adequate Intake (AI)
Most common dietary deficiency
Anemia
Iron-deficiency anemia
Sluggishness, loss of appetite, decreased ability to sustain activity; negatively affects aerobic performance
Osteoporosis
inadequate calcium intake; vitamin d can help increase calcium absorption
Weight loss by low calories leads to…
Loss of lean mass
Atwater factors (kcal/g)
Carbs: 4
Lipids: 9
Proteins: 4
Alcohol: 7
Sleeping metabolism, basal metabolism, arousal metabolism; 60-75% of energy expenditure
Resting metabolic rate (RMR)
Thermic effect of feeding
5% or 10%
PAI
1.3 sedentary, 1.5 moderately active, 1.7 very active
Harris Benedict Eq
Mifflin St. Jeor Eq
Sources of energy for exercise
glycogen from liver/muscle
fat from adipose tissue
Protein (amino acids) from muscle
Purpose of Na in rehydration drinks
reduce risk of hyponatremia
Energy balance
if you consume the same amount of kcals that you are expending, then you will maintain weight
Consume 3500 extra kcal
gain 1 lb
Burn 3500 additional kcal
lose 1 lb
Proactive approach to hydration
1 mL fluid/1 kcal consumed
Our bodies are often warmer than the environment, so net exchange of radiant heat energy occurs from our body to the air
Radiation
Heat transfers directly through solid, liquid, or gas from one molecule to another
Conduction
Effectiveness of heat loss by convection depends on how rapidly air near the body exchanges once it warms
Convection
Evaporation of sweat provides major physiologic mechanism for heat loss
Evaporation
Factors that determine heat strain
body size/fitness
level of training
acclimatization
adequacy of training
external factors
Relative humidity and sweat loss
As relative humidity increases, the apparent temp increases, posing a risk to dehydration and exhaustion
Intracellular fluid
30%; depends on intracellular potassium and phosphate concentrations
Extracellular fluid
23%; depends on extracellular sodium and potassium concentrations
Electrolyte in highest concentration in sweat
Sodium, followed by chloride and potassium
water/sweat loss and equivalent in cups for replacement fluid
drink 2-3 cups of fluid for every pound lost
Western diet
energy dense foods and obesity common
ES group: Starch
15 g carb, 3 g protein, 1 g fat
ES group: fruit
15 g carb
ES group: milk/milk subs
12 g carb, 8 g protein, fat depending
ES group: nonstarchy vegetables
5 g carb, 2 g protein, 0 g fat
ES group: protein
0 g carb, 7 g protein, 2 g fat
ES group: fats
5 g fat
Moderate exercise and immune system
will up-regulate immune system
