chap 4 (glucose) Flashcards
carbon is composed of what
carbon + hydrogen
healty benefits of soluble dietary fiber
} Lowers cholesterol
} Maintains bacterial population
of gut
} Helps regulate blood glucose
} Increases satiety
} Delays gastric emptying
} Prevents weight gain
healthy benefit of insoluble dietary fiber
} In intestine: Adds bulk, Helps retain water
} Reduces the risk of: constipation, hemorrhoids,
diverticulosis, & diverticulitis
} May reduce the risk of some
cancers
(e.g. colorectal)
what is the current recommendation for dietary fiber for male and female age 19-50 and over 50
male
19-50 yrs: 38g
>50 yrs: 30g
Female
19-50 yrs: 25g
> 50yrs: 21g
where does the majority of digestion occurs
duodenum of small intestine
where does the major of absorption occurs
jejunum and ileum of small intestine
carb are found in food as
sugars, starches and cellulose
what is the primary energy source for moderate to intense exercise
carbs
largest amount of carb in the body is stored in the form of _ and smaller amounts are stored as _
glycogen in skeletal muscle, liver glycogen
which type of carbs don’t provide energy and why
cellulose in starchy food because human don’t posses the enzyme to digest it
but important because it contain fiber, vitamins and minerals
which carbs don’t contain vitamins and minerals or fiber
sugars
glucose is transported from the intestinal lumen into the epithelial cell by what
a sodium and glucose cotransporter
what happen if the amount of carb in small intestine is greater than the number of carrier present
some of these sugars will not be absorbed
when fructose is not absorbed from the small intestine what can happen
it will passes through to the colon, ferments and cause gastrointestinal distress (bloating and gas)
what are the 2 most predominant hormone of glucose regulation
insuline and glucagon
what happen when blood glucose concentration is elevated after eating
insulin is secreted from beta cells of pancreas to stimulate transport of glucose
what happen when blood glucose is low
glucagon is secreted from the alpha cell of pancreas to stimulate the release of glucose stored as liver glycogen
hyperglycemia stimulate which hormone
hypoglycemia stimulate which hormone
hyper: beta
hypo: alpha
fructose is absorbed where
intestinal epithelial cell
what happen when food with a higher GI is consumed
blood glucose rises more quickly, reach higher level and decline more quickly than food with lower GI
insuline response is also higher even if the same amount of glucose is consumed
exemple of food with high GI
white bread, corn flake, baked potato
exemple of food with low GI
legume, bean, fruit, non starchy vegetable, dairy product
How glucose is metabolized depends on a variety of
factors:
type of cell, enzymatic capability of the cell,
energy state, hormonal status, training history, and
intensity of exercise.
when is food considered low GI or high GI
low: GI <60
high: GI >85
The process of producing glucose from other sources
is called
gluconeogenesis
the major sources for glucose for-
mation by gluconeogenesis are
lactate and amino acids, glycerol
which organ is important in controlling blood glucose
pancreas
Exercising muscle preferentially uses carbohydrate from
stored glycogen
Glucose is
made available in the blood from the liver as a result
of at least three processes:
the breakdown of liver gly-
cogen, the production of glucose from other sources
(gluconeogenesis), or the ingestion of carbohydrates
as food or fluids,
how fatigue occurs during prolonged endurance exercise and intermittent high-intensity exercise like repeated sprint in a soccer match
glycogen depletion
Liver glycogen is broken down
and released into the blood as glucose, a process
called
glycogenolysis
which transporter is there at rest or when insuline is low in the blood
GLUT 1
which transporter is there when glucose and insuline are high or muscle is active
GLUT 4
GI is calculated relative to which food
white bread
modate GI value
60-85
high fiber contain is low or high in glucose contain
low
pre-exercise meal is associated with how or low GI
low
during high-intensity or long duration exercise GI is low or high
moderate to high
after exercise GI is low or high
high with glycogen depleting during exercise, moderate to high GI CHO
how does aerobic training increase aerobic capacity of muscle
- increase number and size of mitochondria
- increase oxidative enzyme acitivity
- increase muscle glycogen stores
- increase oxidative capacity -> increase fat utilization
hormone change during exercise that stimulate breakdown of stored energy
- insuline decrease
- glucagon: increase
- cortisol: increase
- epinephrine: increase
- norepinephrine: increase
what is the classic protocol of CHO loading to maximize glycogen
day 1: cycle @ 75% to exhaustion
day 2-3: fat+protein diet
day 4: cycle @ 75% to exhaustion
day 5-6: high CHO: 8.2 g/kg/d
day 7: competition
modified protocol for CHO loading to maximize glycogen
day 1: 90min run @ 75%
day 2-3: mixed diet + 40min run
day 4-5: high CHO diet + 20min run
day 6: high CHO diet + rest
day 7: comp
carb intake <24h before exercise
- high CHO
- CHO = 60-70% of total calorie, balance and moderation protein and fat
goal carb intake before completion
3-5h prior: repletes liver glycogen and some muscle glycogen
1h prior: repletes liver glycogen, increase delivery CHO to muscle
carbs intake before competition
1-4h prior:
- 1 to 4g CHO/kg body weight
- easily digestible food and beverage
- low to moderate fiber
- mainly CHO -> dairy product, small amount of legume
- low GI
- fluid: water, milk, juice
what happen if CHO is take 30-60min prior to exercise
- decrease plasma glucose
- increase CHO oxydation and glycogenolysis
- blunted FA mobilization and oxydation
NOT generaly detremental to performance
Factors that determine glycemic response
Insulin and contractile activity on muscle glucose uptake
¡ Balance of insulin and catecholamine effects on liver glucose output
¡ Magnitude of ongoing intestinal absorption of ingested CHO
how to prevent reactive hypoglycemia
Timing of CHO ingestion
¡ More prevalent 75 min prior to exercise
¡ Less 45 min prior and fewer 15 min prior
¡ Prevented 5 min prior and with warm up
how does CHO intake contributed to improved performance
- Maintaining blood glucose and high levels of CHO oxidation
- Glycogen sparing in liver (and maybe muscle)
- Promotes glycogen synthesis during exercise
- Affects motor skills
- Affects CNS
what is the mouth rinse phenomenon and how does it enhance performance
Hypothesis: CNS might sense CHO presence via receptors in oral space,
increasing sense of well-being and improving pacing.
- CHO (sweet and non-sweet) in mouth activates brain reward and
motor control. - Enhances performance 2-3%
what type of CHO should be consumed during exercise, training or competition
very rapidly oxidized CHO
- glucose
-sacrose
- maltose
- maltodextrins
- amylopectin
name some slowly oxidized CHO
fructose
galactose
amylose
trehalose
isomaltose
Exogenous CHO increases with increasing intensity up to
50% VO2max
CHO intake consideration
- Duration and intensity
- Type of Exercise
- Maybe not allowed during or necessary
- Food/Fluid preferences of athlete should be taken into account
- Availability
goal of carb ingestion after exercise
replenish stores of muscle and liver
rate of glycogen synthesis
depend on;
- glucose availability
- transport of glucose into cell
- activity of enzyme
carbs ingestion after exercise
timing, meal size, type
at least within 2h
smaller, frequent
fructose <glucose, high GI
form and amount of carbs ingestion after exercise
solid=liquide
1.5 g/kg in first hour
1-1.2 g/kg for next 3h
which one between CHO and protein is important to ingested after exercise
CHO
how many carbs is needed to replenish it to a level that allow training for consecutive day
5 g/kg/day
goal of intake of CHO prior training or competition
include
avoiding hunger, delaying fatigue, minimizing gas-
trointestinal distress, and preventing hypohydration
Which of the following two monosaccharides combine to form sucrose?
a. glucose and fructose
b. galactose and glucose
c. glucose and glucose
d. galactose and fructose
a
Which of the following are
polysaccharides?
a. starch
b. fiber
c. glycogen
d. all of the above
d
The end product of carbohydrate absorp-
tion is:
a. fructose.
b. glucose.
c. lactose.
d. maltose
b
In what form is carbohydrate primarily
transported throughout the body?
glucose
hrough a process called gluconeogenesis,
glucose can be made in the body from which of
the following?
a. glycerol
b. lactate
c. amino acids (for example alanine)
d. all of the above
d
The glycemic index (GI) of a food refers to:
a. the number of grams of carbohydrate in the food
b. the number of kilocalories of carbohydrate in the food
c. the blood glucose response to a food compared to a reference food
d. the amount of simple sugars or monosaccharides in the food
c
Exercising muscle prefers to use carbohy-
drate from:
a. blood glucose.
b. liver glycogen.
c. muscle glycogen.
d. any carbohydrate source available (no preference).
c
As exercising muscle begins to take up
glucose out of the blood, how does the body pre-
vent blood glucose from declining too much?
a. the muscles stop taking up glucose
b. the liver releases glucose from stored glycogen and made by gluconeogenesis
c. the pancreas releases insulin, which reduces glucose uptake from the blood
d. the body switches to fat metabolism
b
The recommended range of daily carbohydrate for athletes in training is:
a. 3 to 12 g/kg.
b. 5 to 10 g/kg.
c. 6 to 8 g/kg.
d. 7 or more g/kg.
a
The two factors needed to optimize muscle glycogen resynthesis after exercise are:
a. carbohydrate and excessive caloric intake.
b. carbohydrate and lactate.
c. carbohydrate and protein.
d. carbohydrate and insulin.
c
Which of the following would not be an
appropriate carbohydrate food choice for a vegan?
a. starchy vegetables
b. beans and legumes
c. milk and yogurt
d. nuts and fruits
c
Which of the following is true about ath-
letes with type 1 diabetes?
a. Because of their disease, people with type 1 diabetes are not able to participate in competitive sports.
b. Because of their disease, people with type 1 diabetes are able to participate in competitive sports but cannot perform at a high level because of their inability to metabolize carbohydrates.
c. People with type 1 diabetes cannot perform at a high level in competitive sports because the drugs they must take are banned.
d. People with type 1 diabetes can perform at a high level in competitive sports by properly managing food intake, blood glucose levels,
insulin injections, and their exercise regime
d
