Transcript Carbohydrates

Levels of Organization in the Human Body
Brief Introduction to Chemistry of Biology
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H= 1
O= 2
N= 3
C=4
The carbon atom a is made up of the 3 sub-atomic particles:
protons, neutrons and electrons
The valance electrons = e-s in outermost shell. These determine the
chemical properties of an atom and the bonds they make with other atoms
3 Types of Chemical Bonds:
• Covalent bonds – a sharing of electrons between, strong bonds.
Non-Polar: equal sharing of electrons. e.g. C=C
Polar: unequal sharing of electrons. e.g. H2O
• Ionic bonds – complete transfer of electrons, relatively weak bond (crystals
strong), break in water. e.g., NaCl becomes Na+ and Cl- in water!
• Hydrogen bonds – attractive forces between
H atoms and O or N atoms.
Very weak but important.
Carbohydrates
Simple and Complex
Monosaccharides* - simple sugars (monomers).
1. Glucose – the molecule as a source of E in the human body.
2. Fructose – a simple sugar found in fruits (fruit sugar).
3. Galactose – a component of milk sugar.
*Consist of 3, 5 or 6 C atoms
Disaccharides - 2 monosaccharides joined by a glycocydic bond.
1. Sucrose (table sugar) = glucose + fructose
2. Lactose (milk sugar) = glucose + galactose
3. Maltose (grain sugar) = glucose + glucose
Polysaccharides** - complex carbohydrates – polymers of glucose.
1. Glycogen - E storage for glucose in animal cells, liver, skeletal mus.
2. Starch - E storage for glucose in plant cells, e.g., potatoes!
3. Cellulose - structural component of plant cell walls, e.g., dietary fiber!
**Macromolecules formed by 9 or more monosaccharides
How Glucose is Made? Photosynthesis:
Where are the Carbs in our Diet?
Ug, not this useless, ridiculous food structure again?
A Better Food
Structure?
COCONUT OIL!
Monosaccharides
Single sugar molecules
Can be classified by number of C atoms in a molecule:
n=3
trioses, e.g. glyceraldehyde (‘tri’ = 3)
n=5
pentoses, e.g. ribose and deoxyribose ('pent' = 5)
n=6
hexoses, e.g. fructose, glucose and galactose ('hex' = 6)
The monosaccharides Important in Nutrition are the Hexoses:
1. Glucose - found in all cells; main source of E for brain and RBC’s.
2. Fructose - found in fruit and honey.
3. Galactose - found in milk.
Glucose is C6H12O6
The Structural Differences between
Glucose, Fructose, and Galactose
Glucose – what all the polymers are made out of!
Note different orientation of OH group = the α and β
glucose molecules.
*Important when forming polymers - creating dietary
differences between starch and cellulose.
Sugar
fructose
sucrose
glucose
maltose
galactose
lactose
Sweetness
173%
100%
74%
33%
33%
16%
Fructose is naturally the most sweet tasting of all the sugars!
High Fructose Corn Syrup (HFCS)
HFCS 42
HFCS 55
HFCS 90
- beverages, processed foods, cereals, baked goods
- used in soft drinks
- extremely sweet e.g. ‘crystalline fructose’ (more rare)
HFCS Promotes Diseases; Makes Diabetes Mellitus Worse
 fat deposits in liver, increasing buildup of lipoproteins .
Can lead to plaque buildup and narrowing of blood vessels.
 Risk of Metabolic Syndrome – by consuming too much HFCS in
food and drinks. HFCS worsens diabetes.
Damages Immune System -  asthma, food allergies, multiple
sclerosis (MS).
Speeds-up aging process – Your poor liver and other vital organs
must work much harder than they should.
Mercury (Hg) from commercial processing found in HFCS.
Disaccharides
Two sugar molecules linked together…
Nutritionally Important ones are:
Maltose - 2 glucoses molecules (alpha bond)
Found in seeds and grain: “Grain” sugar.
Lactose - glucose and galactose (beta bond)
Found in dairy products: “Milk” sugar.
Sucrose - glucose and fructose (alpha bond)
Found in plants: “Table” sugar.
Dehydration Synthesis Reactions take
Monosaccharides and make Disaccharides
Oligosaccharides
• From 3 to 10 monosaccharides long.
• Have a sweet taste and unique ‘mouth feel’.
• Food Examples: onions, artichokes, chicory root,
legumes, asparagus, wheat and jicama.
Nutritional Benefits
Basic Category Examples
Fructo-Oligosaccharides (FOS), in veggies, short chains of fructose.
Galacto-Oligosaccharides (GOS), short chains of galactose.
2 Important specific examples are:
1. Raffinose- indigestible (galactose-glucose-fructose).
2. Stachyrose- indigestible (galactose-galactose-glucose-fructose).
Nutritional Benefits - Eating oligosaccharides allows the
undigested portion to feed beneficial bacteria (intestinal
microflora) and can simultaneously reduce population of
harmful bacteria.
Polysaccharides
Starch – storage form of
glucose in plants.
Amylose- straight chain
Amylopectin- branched
Glycogen – storage form of
glucose in animals;
highly branched chain.
Cellulose – structural
component of plant cell
walls.
All of the Polysaccharides in Human
Nutrition are made up of many
molecules of …
GLUCOSE
Therefore, when these molecules are broken down, all they liberate is… Glucose
Whole Food
Refined Food
Unrefined, entire original “item”
Heavily processed from original form
All original nutrients remain intact
Most (if not all) original nutrients removed
Unprocessed, not chemically treated
Chemically treated (in processing & for shelf-life)
Glycemic Index (GI) indicates how quickly a certain food turns
into sugar (glucose) in a person’s body.
Glycemic Load (GL) indicates the total amount of glucose in the
food. Calculate the total amount in terms of average serving.
Glycemic Load = Glycemic Index x Carbohydrates / 100
Processed Food
76 GI x 23 net carbs /100 = 17.5
Whole Food
38 GI x 15 net carbs /100 = 5.7
Refined Processed Foods
White Bread
Candy and Soda
Low fat Yogurt
Girl Scout Cookies
Whole Foods
Complex Organic Vegetables
Brown Rice or Quinoa
Nuts and Legumes
Fresh Organic Fruits
• Starch
Plants store glucose in chains of starch.
Amylose: Straight chains in starch;
40% of starch is amylose
More resistant to digestion vs amylopectin
Amylopectin: Branched chains of in starch;
60% of starch is amylopectin
Easier to digest
Polysaccharides
Starch
Polysaccharides
Examples of Starchy Foods:
o Grains - wheat, rice, barley, oats, corn,
and potatoes, beans
o Bread, cereal and pasta, crackers, biscuits, cookies,
cakes, pie crust, all things made with flour (amylose).
o The amylose is broken down quite slowly
Therefore, the higher amylose more slowly it is digested.
o Long grain rice - which tend to stay more separate,
higher in amylose, lower glycemic index.
o Short grain rice - which tend to make creamier, stickier rice
lower in amylose, higher glycemic index.
Cooking Techniques can affect Starch Digestion
Pasta is a processed food however, when cooked "al dente"
(slightly firm) it’s digested more slowly, plus starch molecules
tightly packed, only about half is rapidly digested.
Most Bean starch structure only slowly broken down into sugars.
Some cooked starches, such as potatoes and rice, when cooked
and cooled, a small percentage of the starch takes longer to
digest.
New Vs. Mature Potatoes - ‘new’ have starch more like amylose
in structure than mature, and they are somewhat less glycemic.
* Similar to “Resistant Starch” like under-ripe bananas
Polysaccharides
Glycogen is amylopectin with very short distances
between the branching side-chains.
Stored in: Liver, Skeletal Muscle and Uterus.
Glucose easily passes into cells and is used in
metabolism.
Glycogen is
highly branched
compared to starch
Polysaccharides
Any spare glucose is grabbed by the liver which
has a limited capacity to store it as Glycogen.
Inside Hepatocytes of Liver, glucose can be
polymerized to make glycogen which acts as a
carbohydrate energy store.
Polysaccharides
Cellulose – Contains Various Fibers…
What is Fiber?
Fibers or ‘roughage’ refers to a diverse group of
indigestible carbohydrates found in plant foods.
The molecules are linked together by chemical
bonds our enzymes can not break
Therefore, they pass through our G.I. tract undigested system by us.
You can think of the main difference between starch and
cellulose this way: The Glucose in Cellulose has every other
glucose molecule ‘upside down’, and we do not have the
enzyme to break that arrangement!
Is this Starch or
Cellulose?
Fibers are polysaccharide molecules where
the sugars are linked together by chemical
bonds our enzymes can not break.
Including vegetables, fruits, legumes, whole
grains, nuts and seeds. This is a category of
carbohydrates that humans cannot digest.
Recommended daily intake is:
38 g/day for men and
25 g/day for women.
most people only get 15 g/day.
Classifications of Fiber
Fibers can be divided by solubility
– Insoluble
– Soluble
Insoluble fibers: include compounds such as:
Lignin, Cellulose and Hemicellulose
• Adds bulk to the fecal material, helps keep it
moving through the colon.
• Found in vegetables and whole grains.
Classifications of Fiber
Soluble fiber includes: Pectins*, Gums**, and
Mucilages*** (e.g. psyllium)
Slows rate that chyme is released from stomach
– Slows absorption of glucose
– Can lower cholesterol
• Found in fruits, citrus fruits, oat products, and
beans
*causes jams and jellies to gel
**e.g. xanthan gum, gums things
*** a thick, gluey substance
produced by nearly all plants
Classifications of Fiber
Fermentable Fiber
~100 trillion bacteria reside in our gut (large intestine).
These bacteria are crucial for optimal health in humans.
Role in:
Cellulose - insoluble fiber
e.g., in skin of fruit
Body Weight
Blood sugar control
Immunity
Brain Function
Pectin -soluble fiber
Mental health
e.g., in flesh of fruit
The friendly gut bacteria (gut flora) often referred to as the
“forgotten organ”.
The fiber reach the large intestine mostly unchanged.
Our good gut bacteria are able to digest use these fibers as
fuel via fermentation!
This ↑ the # and balance of friendly gut bacteria, They make
Vitamin K and short chain fatty acids with powerful health
benefits for us, in return for all that yummy fermentable fiber.
Fermentable fibers include pectins, beta-glucans, guar
gum, inulin and oligofructose.
The best whole-food sources of fermentable fibers are beans
and legumes. 1 Cup/day = DRI!
short chain FA’s
Vit K
By-products of fiber fermentation = gas.
In Summary:
Fibers that are soluble, viscous and fermentable appear to be
the healthiest.
Good sources of healthy fibers include vegetables, fruits,
oats, legumes, nuts, dark chocolate, avocados, chia seeds.
Carbohydrate Digestion
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Begins in the mouth.
Teeth grind food and mix with saliva.
Saliva contains lingual amylase.
Swallowed – the Bolus goes down the esophagus to stomach.
No carbohydrate-digesting enzymes in the stomach.
• The pancreas releases pancreatic amylase as carbs enter the
small intestine.
• Enzymes break down the disaccharides into monosaccharides.
• Absorption of starch and simple sugars occurs in small intestine.
• Only the indigestible fiber remains in Large Intestine.
Absorption of Carbohydrates
Absorption of Carbohydrates
• In the Small Intestine - broken down to simple sugars and
then absorbed!
• Absorption primarily done through a co-transport system
• Glucose is taken into intestinal epithelium with sodium
ions (Na+) and released when sodium ions are pumped
out of the cell
• Transported to Liver
– Release into blood stream
– Converted into glycogen
– Converted into fat
Functions of Glucose and Sugars
• Energy
• Building blocks for other cell components
• Spares protein from being used as energy
source
• Prevents ketosis
• Cell surface markers and receptors
Lactose Intolerance
Consequence of lactase deficiency, and the inability of adults
to digest lactose no enzyme to break glucose-galactose bond.
May be genetic or environmental
Symptoms: after consuming significant amounts of lactose.
abdominal bloating,
cramps,
flatulence
Lactase activity is high in newborns,
diarrhea
but declines after weaning.
nausea,
borborygmi
Most can handle ½ to 1 cup of milk with a
vomiting
meal; lactose containing foods with more
fat meal helps reduce discomfort
Regulation of Blood Glucose
• Normal BG is 70-100 mg/dl
• After a meal, insulin levels rise which helps to store away
glucose into tissues
• If fasting glucagon levels rise, mobilizing glucose from
storage into the blood
• Epinephrine and NE both are released during sympathetic
NS activation, mobilizing glucose into the blood
• Cortisol and Growth Hormone decrease glucose use by
muscle, but increase blood glucose
When blood Glucose is high
Insulin is released to make
blood Glucose lower (normal)
Cells in your body
up-take the glucose
When blood Glucose is low
Glucagon is released to make
blood Glucose higher (normal)
Liver is a key site:
Hepatocytes liberate Glucose
stores (glycogen) and use fats
& proteins to make more
glucose
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Glycogenolysis
Regulation of Blood Glucose
• Hyperglycemia (fasting 126 mg/dl)
• Hypoglycemia (fasting below 50 mg/dl) symptoms:
– irritability, sweating, anxiety, weakness, headache,
confusion
– Reactive hypo- due to exaggerated insulin response
after eating
– Fasting hypo- low BG after fasting for 8+ hours
Comparison of Molecules (120 Kcal each)
Glucose
2 slices of bread.
Sucrose
1 glass of orange juice.
Ethanol
1 shot of bourbon.
Glucose
Sucrose
2 slices of bread
1 glass of orange juice
1 shot of bourbon
Starch => glucose
60 kcal glucose +
60 kcal fructose
CNS Depressant
~96 kcal used by all
cells in body
~48 kcal used by all
cells in body
~24 kcal used by all
cells in body
~24 kcal hits Liver
for Metabolism
~72 kcal hits Liver
for Metabolism
~96 kcal hits Liver
for Metabolism
Glucose-6-℗
Makes Glycogen
~0.5 kcal used for
de novo Lipogenesis
↑ Insulin
Inhibits Ghrelin
Glucose-6-℗
↑ Aldehydes
↑ Uric acid
↑ VLDL + ↓NO = ↑BP
↑ de novo Lipogenesis
No effect on Ghrelin
Ethanol
↑ Aldehydes
↑ Acetate
↑ Citrate
↑ VLDL
↑ de novo Lipogenesis
Dislipidemia
↑Insulin resistance
Metabolic Syndrome
Is a state of numerous metabolic factors existing in one
individual which include:
1.
2.
3.
4.
5.
6.
High Blood Pressure
Abdominal Fat
High Blood Triglyceride levels
High Uric Acid levels
Insulin Resistance
State of Chronic Inflammation
Risks = Cardiovascular Disease and Diabetes Mellitus Type II .
* Est. over 50 million Americans have this condition.
* Hypothesized link to over consumption of high-fructose corn syrup
(HFCS) and metabolic syndrome.
Which one would you choose?
Why do we make
the choices we make?
Do you believe that Nutritional Labels on
Packaged Food tell you all the information
you might want to know about what that
food actually contains?
• If so, why?
• If not, what are some examples of how
food manufacturers might used deceptive
practices to lead you to believe something
about the product that is untrue?
Girl Scout Cookie Label
* Tertiary Butylhydroquinone (TBHQ)
Conventional
Pesticides, growth hormones, stimulants,
Genetically Modified Organisms (GMO)…
Organic
None of those harmful elements
But more than that...
Salvestrols
Synthesized by plants, they belong to a group of
phytochemicals called phytoalexins. Plants
produce this in response to attack by pathogenic
organisms such as fungi, viruses and bacteria.
Resveratrol first of the salvestrols discovered.
Highest amounts found in Green Vegetables
and Red Fruits, also higher in bitter foods!
Resveratrol
Antioxidant, anti-aging, cardiovascular protectant…
Content of Resveratrol in selected foods
Food
Serving
Total Resveratrol (mg)
150 ml
0.30 – 1.07
Red Grapes
160 g
0.24 – 1.25
Cocoa Powder
200 g
0.28 – 0.46
Red Wine (Global)
CYP1B1 – a cancer enzyme (marker)
found in all types of cancer cells:
e.g. bladder, brain, breast, colon, esophagus, kidney, liver,
lung, lymph node, ovary, skin, stomach, testis and uterus…
*Several dozen more salvestrols have subsequently
been discovered in organically grown fruits and
vegetables.
Over 90% more Salvestrol content in Organic Produce.
How Salvestrols Work
Cancer cell
Normal cell
So fruits and vegetables really are good for you!