Transcript Carbohydrates - National Personal Training Institute of

Carbohydrates
Roles of Carbohydrates
• Definition: organic substance made of
carbon, hydrogen, and oxygen that supplies
the body’s main source of energy
• Macronutrient
• Direct energy source- 4 kcal per gram
• Adequate carbohydrate intake preserves
tissue protein
• Fuel for the central nervous system (CNS)
and red blood cells
• Prevents ketosis
Role of Carbohydrates
• Sufficient carbohydrates prevent the rapid
breakdown of fat that would produce ketones
• Ketones are chemicals produced by the liver
when the body cannot use glucose and must
break down fat for energy
• Ketones can poison and even kill body cells.
• When ketones build up, the body gets rid of
them in the urine
• Ketosis slows down fat metabolism
Ketones
• During long-term starvation, proteins in the
muscles, heart, liver, kidneys and other vital
organs break down into amino acids and
certain forms are turned into needed
glucose.
• Overtime these organs become partially
weakened.
• Ketones that accumulate in the body over
long periods of time can lead to serious
illness and coma.
• Eventually ketone buildup can develop into
ketosis and the ketone bodies will disrupt the
body’s normal acid-base balance
Function of CHO’s
• Low glycogen stores or inadequate
carbohydrates intake may cause
cardiac disorder and angina (chest
pain)
• Central Nervous System (brain and
spinal cord) has no stored supply of
glucose; therefore it is dependent on
a minute-to-minute supply of glucose
Nature of Carbohydrates
• Reaction driven by energy from
the sun reacting with chlorophyll
• Photosynthesis: transforms solar
energy into carbohydrates
• H20 + CO2 chlorophyll Glucose
Energy Production System
• Digestion of CHO’s is broken down into
glucose
• Absorption of glucose goes through the
blood circulation
• Insulin allows for glucose utilization into
the cells
• Glucose is burned in the mitochondria
making ATP through cellular respiration
Mitochondria
• Produces ATP
from glucose
• Found in all
cells
Classes of CHO’s
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Carbohydrate = sugar
Saccharide means sugar in Latin
Classified according to sugar units
Monosaccharide: one sugar
molecule
• Disaccharides: two sugar molecules
• Polysaccharides: chains of sugar
molecules, usually glucose
Monosaccharides
• Glucose- C6H12O6
• Fructose- C6H12O6
• Galactose- C6H12O6
Glucose
• Glucose is also
called dextrose or
blood sugar
• Used directly by the
cell for energy
• Stored as glycogen
in the muscles and
liver
• Converted to fat and
stored for energy
Fructose
• Fructose is also called levulose or fruit
sugar
• Absorbed in the small intestine and
transported to the liver where it is
quickly metabolized and converts to
glucose
• Can form into fat if consumed in highamounts
• Often found in fruits
Galactose
• Galactose forms milk sugar called
lactose
• Large quantities of pure galactose
do not exist in nature
• The body converts galactose to
glucose for energy metabolism
Disaccharides
• Combining two monosaccharide
molecules forms a disaccharide
• Each disaccharide includes
glucose as a principle component
• Sucrose: Common table sugar (glucose
+ fructose)
• Lactose: The sugar in milk and not
found in plants (glucose + galactose)
• Maltose: Not found in diet. An ingredient
used during the production of alcohol.
(glucose + glucose)
Polysaccharides
• Starch and fiber are two
common forms of plant
polysaccharides
• Starch
- Plant starch accounts for
approximately 50% of the total
carbohydrate intake of
Americans
- The term “complex
carbohydrate”commonly refers
to dietary starch
Fiber
• Fiber is a polysaccharide
• Humans lack the necessary
enzymes (a protein that
accelerates a specific chemical
reaction without altering itself )
to digest fiber
• No direct energy value
• Fibers can be water-soluble:
gums and pectin
• Water-insoluble: cellulose,
hemicellulose, and lignin
Water Soluble vs Water Insoluble Fiber
• Water Soluble Fiber:
–Mixes well with
water
–Slows digestion
–Can help with
weight loss
–Helps regulate
blood sugar levels
and cholesterol
Water Soluble vs Water Insoluble Fiber
• Water Insoluble Fiber:
– Is not soluble in water.
No physical change
when it enters small
intestine.
– Passes through our
digestive system in
close to its original
form
– Helps to prevent
constipation, colon
cancer and other
digestive diseases
Food labels with Dietary Fiber and with
Soluble/Insoluble Fiber
Roles of Fiber
• Retains considerable water and thus gives
bulk to the food residues in the intestines
• Binds or dilutes harmful chemicals
• Shortens transit time for food residues (and
possibly carcinogenic materials) to pass
through the digestive tract
• There is no RDA for soluble and insoluble
fiber.
• There is an RDA for overall fiber. It is best
advised to get a good combination of both
Fiber Intake and Sources
• RDA= 20-40 grams daily
• Common sources of soluble fiber:
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Barley
Oatmeal
Oatbran
Apples
Bananas
Blackberries
Oranges
Grapefruit
Broccoli
Brussel Sprouts
Carrots
Nectarines
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Peaches
Pears
Plums
Prunes
Black Beans
Kidney Beans
Navy Beans
Black Eyed Peas
Lentils
Chickpeas
Fiber Intake and Sources
•Common sources of insoluble fiber:
• Bell Peppers
• Wheat Bran
• Green Beans
• Potatoes
• Corn
• Peas
• Seeds and Nuts
• Pineapple
• Strawberries
• Skins of fruits and
• Raisins
vegetables
• Spinach
• Whole-wheat and
• Cucumbers
whole-grain
• Tomatoes
products
• Granola
Other Health Benefits of Fiber
• Increases satiety (feeling full), which
aids in obesity prevention
• Promotes normal bowel function
• Adds bulk to stool
• Slows glucose absorption-reducing
blood glucose spikes and reducing
insulin secretion
• Prevents and helps manage
diverticulosis
Diverticulosis
• Diverticulosis:
– A condition marked by small sacs or pouches
(diverticula) in the walls of an organ such as the
stomach or colon. These sacs can become inflamed
and cause a condition called diverticulitis, which
may be a risk factor for certain types of cancer.
Carbohydrates Stored as Glycogen
• Glycogen is the storage
polysaccharide found in mammalian
muscle and liver
• Glycogen is synthesized from glucose
during gluconeogenesis
• Glycogenolysis is the reconversion
process; it provides a rapid extra
muscular glucose supply
Digestion of Carbohydrates
• Mechanical Digestion: Muscular
contractions called peristalsis break food
mass into smaller particles
• Chemical Digestion: Enzymes break down
food into smaller particles
• Chemical and Mechanical Digestion
begins in the Mouth
• Mastication: Chewing
Digestion of Carbohydrates
• Chewing mixes with saliva to start the
breakdown of starch
• Stomach: mechanical digestion only,
20-30% of carbohydrates have been
converted to maltose
• Small Intestine: Chemical digestion is
completed here by enzymes from the
pancreas and intestine
Body Needs for Carbohydrates
• 45% -65% daily or 225-325 g
based on a 2,000 calorie/ day
diet
• 20-40 grams of fiber daily
• Limit sugar to no more than
25% of total calories
Refined Carbohydrates
• “Refined,” when referring to processed
carbohydrates, means they have been stripped
of their fiber and the many nutrients now known
to be cancer-fighters, critical for heart health,
helping to stabilize blood sugar and even
enhance bone health.
• Necessary nutrients like Vitamin E, magnesium,
boron, folic acid, zinc and phytochemicals like
lignans, phytoestrogens and phenolic acids are
all present in these great unrefined whole
grains.
Know Your Grains
• Whole grains are defined as grains that
contain the completed kernel-all three
parts:
1. Bran is packed with fiber B vitamins
2. Endosperm contains carbohydrates and
proteins
3. Germ is rich with B vitamins, minerals,
and phytochemicals (substances in plants)
• Refined grains have most of the bran and
germ removed
Know Your Grains
Test Yourself
1. Which breads are usually all or mostly whole
grain?
(a)whole wheat (b) multi-grain (c) rye
(d) pumpernickel
2. Which grains are whole?
(a)bulgur (b) quinoa (c) couscous
(d) oatmeal
3. What’s the most nutritious grain?
(a)corn meal (b) millet (c) quinoa
(d) oatmeal
1. Answer: a
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Whole wheat refers to the whole
complete wheat shaft
In theory, multi-grain, rye and
pumpernickel breads can be whole
grain - you must check the labels
though. If it lists one of these whole
grains first, it usually is
If it says made with enriched or
wheat flour, multi-grain flours or
pumpernickel flours, then it is
mostly refined grain
2. Answers: b and d
•Quinoa and oatmeal are whole grains
•Bulgur and couscous may also be but
check for the whole grain wording on
the label.
Quinoa
3. Answer: c
•Quinoa has been a staple food to the natives of
the South American Andes since 3000 BC
•Quinoa has the highest protein content of any
grain
•It is one of the grains highest in calcium, iron,
copper, magnesium, Vitamin E, phosphorus and
B vitamins.
•Quinoa is great for a vegetarian diet because of
lysine and methonine, two amino acids which are
generously supplied by this grain and notably low
in vegetarian diets
•Quinoa has a delicious nutty flavor and crunchy
texture
Top 5 Healthiest Grains
1. Quinoa (pronounced keen-wah)
2. Buckwheat Groats (when roasted called
Kasha)
3. Barley
4. Millet (it is considered to be one of the least
allergenic and most easily digestible grains)
5. Bulgur
• Other recognized whole grains are oats and
oatmeal, brown rice, wild rice, corn meal,
wheat berries and whole wheat macaroni and
spaghetti.
What to Look for on the Food Label
• Choose foods that name one of the
following whole-grain ingredients first on
the label’s ingredient list:
–brown rice, whole oats, bulgur, whole
rye, graham flour, whole wheat,
oatmeal, wild rice, whole-grain corn
• Foods labeled with the words multi-grain,
stone-ground, 100% wheat, “cracked
wheat”, “seven-grain”, or bran are usually
not whole-grain products.
What to Look for on the Food Label
• Color is not an indication of a
whole grain. Bread can be brown
because of molasses or other
added ingredients.
• Read the ingredient list to see if it
is a whole grain.
Tips to Help You Eat Whole Grains
• Try brown rice or whole-wheat pasta
• Try brown rice stuffing in baked green
peppers or tomatoes and whole-wheat
macaroni in macaroni and cheese
• Use whole grains in mixed dishes, such as
barley in vegetable soup or stews and
bulgur wheat in casserole or stir-fries
• Create a whole grain pilaf with a mixture
of barley, wild rice, brown rice, broth and
spices. For a special touch, stir in toasted
nuts or chopped dried fruit.
Tips to Help You Eat Whole Grains
• Substitute whole wheat or oat flour for up
to half of the flour in pancake, waffle,
muffin or other flour-based recipes. They
may need a bit more leavening.
• Use whole-grain bread or cracker crumbs
in meatloaf.
• Try rolled oats or a crushed, unsweetened
whole grain cereal as breading for baked
chicken, fish, veal cutlets, or eggplant
parmesan.
Tips to Help You Eat Whole Grains
• Try an unsweetened, whole grain
ready-to-eat cereal as croutons in
salad or in place of crackers with
soup.
• Freeze leftover cooked brown rice,
bulgur, or barley. Heat and serve it
later as a quick side dish.
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What is High Fructose Corn Syrup?
Experts are finding that high-fructose
corn syrup (HFCS) is making us fat
High-fructose corn syrup is a highly
refined, artificial product
It is created through an intricate
process that transforms cornstarch
into a thick, clear liquid
Experts agree that high-fructose corn
syrup is worse than sugar
The Dangers of High Fructose Corn Syrup
• This manufactured
fructose is sweeter than
sugar in an unhealthy
way, and is digested
differently in a bad way.
• Research has shown
that high-fructose corn
syrup goes directly to
the liver, releasing
enzymes that instruct
the body to then store
fat
The Dangers of High Fructose Corn Syrup
• This fake fructose may slow fat burning
and cause weight gain
• Other research indicates that it does not
stimulate insulin production, which usually
creates a sense of being full. People may
eat more than they should.
• Increases LDL's (the bad lipoprotein)
leading to increased risk of heart disease
The Dangers of High Fructose Corn Syrup
• Alters magnesium balance leading to
increased risk of osteoporosis.
• Increased risk of Type 2 Diabetes
• It has no enzymes or vitamins thus
robbing the body of precious micronutrients.
• It interacts with birth control pills and
can elevate insulin levels in women
on the pill.
• Accelerates aging
The Dangers of High Fructose Corn Syrup
• It inhibits copper
metabolism leading to
a deficiency of
copper, which can
cause increased bone
fragility, anemia,
ischemic heart
disease and defective
connective tissue
formation among
others.
Where Do You Find High Fructose Corn
Syrup?
• High-fructose corn syrup
is highly valued by food
manufacturers
• It's easy to transport in
tanker trucks
• It isn't susceptible to
freezer burn, as is sugar
• It has a long shelf life and
keeps
foods
from
becoming dry
• It gives bread and baked
products a wonderful
color
Where Do You Find High Fructose Corn Syrup?
• It's also cheaper than white sugar, partly
because of generous federal subsidies and
trade policies that encourage farmers to grow
more corn.
• Fast food chains add it to their products
because it is cheaper.
• It is in the sauces, in the condiments, in the
breadings, in the buns and in soft-drinks
• It is the commercially preferred artificial
sweetener.
• What's worse than sugar? Now you know.
Glycemic Food Index
• The Glycemic Index (GI) relates to the way
your body’s sugar levels respond to certain
foods.
• Foods are given a rating from 0 –100 on the
glycemic index with glucose in the highest
position.
• High Glycemic Index foods (white bread,
white rice, potatoes) will increase the body’s
sugar levels rapidly whereas low glycemic
index foods (lentils, chickpeas, navy beans)
will increase the body’s sugar levels slowly.
Glycemic Food Index
• Foods low on the glycemic index will release
glucose gradually into the blood stream
whereas foods high on the glycemic index will
provoke an immediate response in the blood
sugar levels.
• Foods that contain carbohydrates are usually
high on the glycemic index and have the
greatest effect on blood sugars.
• Pasta dishes, bread and potatoes are usually
high on the glycemic index.
Glycemic Food Index
• If your blood sugar is low and continues to
drop during exercise, you would prefer to
eat a carbohydrate that will raise your
blood sugar quickly.
• On the other hand, if you would like to
keep your blood sugar from dropping
during a few hours of mild activity, you
may prefer to eat a carb that has a lower
glycemic index and longer action time.
• If your blood sugar tends to spike after
breakfast, you may want to select a cereal
that has a lower glycemic index.
Glycemic Food Index
• The composition in the carbohydrate
will also affect how the body’s sugar
levels react.
• For example, white bread will rate
high on the glycemic index whereas
wholegrain or rye bread will be rate
lower on the glycemic index as it
contains more grains and contains
complex carbohydrates.
Glycemic Food Index
• Examples of low glycemic foods are
breakfast cereals (which are based on
wheat bran, barley and oats),
wholegrain break, fruit, lentils,
soybeans, baked beans etc.
• Examples of high glycemic foods are
white bread, soft drinks, full fat icecream, chocolate bars etc.
Nutrition Assignment
• Refer to page 19 in your nutrition
book and answer questions 1-4 in
the Case Study: Identifying
Carbohydrates And Fiber
• Refer to page 29 in your nutrition
book and answer Critical Thinking
Questions 2 and 4