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Proteins are about 50% of the dry weight of most cells, and are the most structurally complex molecules
known. Each type of protein has its own unique structure and function.
Polymers are any kind of large molecules made of repeating identical or similar subunits called
monomers. The starch and cellulose we will discuss discuss are polymers of glucose, which in that case,
is the monomer. Proteins are polymers of about 20 amino acids monomers.
The amino acids all have both a single and triple letter abbreviation. Here is an example.
Alanine = A = Ala
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Each amino acid contains an "amine" group, (NH2) and a "carboxylic acid" group (COOH)
(shown in black in the diagram).
The amino acids vary in their side chains (indicated in blue in the diagram).
The eight amino acids in the orange area are nonpolar and hydrophobic.
The other amino acids are polar and hydrophilic ("water loving").
The two amino acids in the magenta box are acidic ("carboxylic" group in the side chain).
The three amino acids in the light blue box are basic ("amine" group in the side chain).
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Amino Acids: shown in another structural formula format
H O
H O
NH2
C C OH
CH3
NH2
CH
H3C CH3
alanine
ala – A
C C OH
NH 2
C C OH
NH2
C C OH
leucine
leu – L
H O
NH2
C C OH
CH3
isoleucine
ile – I
proline
pro – P
*
CH2
H O
NH2
S
NH
CH2 CH2
CH2
CH2
C C OH
CH2
H O
C C OH
CH CH3
CH
H3C CH3
CH2
CH2
NH 2
CH2
valine
val – V
H O
H O
NH 2
C C OH
H O
H O
H O
NH2 C C OH
CH2
C C OH
OH
H
NH
CH3
phenylalanine
phe – F
H O
NH2
methionine
met – M
H O
NH2
H O
NH2
C C OH
CH OH
CH2
CH3
SH
OH
tyrosine
tyr – Y
threonine
thr – T
cysteine
cys – C
H O
NH2
NH2
C C OH
CH2
O C
OH
aspartic acid
asp – D
H O
NH2
C C OH
H O
NH2
CH2
OH
glutamic acid
glu – E
C C OH
CH2
CH2
CH2
O C
O C
NH2
NH2
asparagine
asn – N
glutamine
gln – Q
H O
C C OH
C C OH
CH2
CH2
CH2
CH2
CH2
CH2
CH2
NH
N
NH
histidine
his – H
2
NH2
NH2
C C OH
CH2
O C
NH2
C C OH
H O
H O
serine
ser – S
H O
C C OH
CH2
C C OH
glycine*
gly – G
tryptophan
trp – W
CH2
NH C
NH2
NH2
lysine
lys – K
arginine
arg – R
Amino acids are named as such because each amino acid consists of an amine portion and a carboxylic
acid part, as seen below.
H O
NH2
C C OH
R
Compare this structure to the above structures of each of the amino acids. Each amino acid has this
general structure.
The side chains are sometime shown as R-groups when illustrating the backbone.
In the approximately 20 amino acids found in our bodies, what varies is the side chain. Some side chains
are hydrophilic while others are hydrophobic. Since these side chains stick out from the backbone of the
molecule, they help determine the properties of the protein made from them.
The amino acids in our bodies are referred to as alpha amino acids. The reason is that the central carbon
is in an alpha position in relation to the carbonyl carbon. The carbon adjacent to the carbonyl carbon is
designated the alpha carbon. Each carbon in the chain will be designated with a different letter of the
Greek alphabet. See the example below.
carbonyl carbon
delta
O
beta
CH3CH2CH2CH2CH2 CH
epsilon
gamma
alpha
Chirality:
A chiral compound must contain a carbon that is bonded to four different atoms/groups. If you look at
the above amino acids you will see that, with the exception of glycine, each structure is chiral around the
carbon with the R group. Each amino acid will come in two structural formats, called enantiomers, an L
and a D. You were given two tables of all the amino acids, the tables are only different in the format that
the amino acids are drawn.
The importance of chiral compounds is that their chemical reactivity is different. Sometimes the
difference means the compound will have an adverse effect on a person. Sometimes the difference
means the person simple can not metabolize the compound. The latter is the case with amino acids.
Meaning we can consume both L and D amino acids, but our bodies will only metabolize the D form.
The enzymes used in the metabolism of amino acids are built to fit this D form but not the L form. The L
form will pass through your body unused.
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Protein Functions:
Type of Protein
Function
Structure
structural support
Contractile
Transportation
Storage
muscle movement
movement of compounds
nutrient storage
Hormone
Enzyme
chemical communication
Catalyze biological reactions
Protection
Recognized and destroy
foreign substances
Examples
collagen in tendons and cartilage
keratin in hair and nails
actin, myosin, tubulin and kinesin proteins
hemoglobin carries O2 and lipoproteins carry lipids
ferritin stores iron is spleen and liver
casein stores proteins in milk
insulin regulates blood sugar
lactase breaks down lactose
trypsin breaks down proteins
immunoglobulins stimulate immune system
Reactions of Amino Acids:
To form protein, the amino acids are linked by dehydration synthesis to form peptide bonds. The chain
of amino acids is also known as a polypeptide.
Protein Structure Types:
Some proteins contain only one polypeptide chain while others, such as hemoglobin, contain several
polypeptide chains all twisted together. The sequence of amino acids in each polypeptide or protein is
unique to that protein, this is call the primary structure. If even one amino acid in the sequence is
changed, that can potentially change the protein’s ability to function. For example, sickle cell anemia is
caused by a change in only one nucleotide in the DNA sequence that causes just one amino acid in one of
the hemoglobin polypeptide molecules to be different. Because of this, the whole red blood cell ends up
being deformed and unable to carry oxygen properly.
The primary structure is created through the linking of amino acids. This linking is accomplished by the
formation of a peptide bond. This is a dehydration reaction. In other words the peptides combine and
lose a water molecule.
The peptide bonding of three alanine amino acids are shown below.
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A longer polypeptide is shown above. Each peptide chain will have an amine end and a carboxylic acid
end and each amino acid is referred to as a residue. So, the ends are named, n-terminal residue and cterminal residue or the n-terminus and c-terminus.
The sequence of amino acids will cause the protein to have areas of its shape conforming to one of 3
shapes, alpha-helical, beta-pleated sheet or woven (sometimes called turns). These are secondary
structures.
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The two most common secondary structures are shown above, alpha helical and beta sheet.
These structures are created by molecular interactions between amino acids. Normally the interactions
are hydrogen bonds. Other interactions will form as well.
 Hydrogen bonds, in the most simple explanation, from between hydrogens attached to an oxygen or
nitrogen and the lone pairs found on an oxygen or nitrogen.
 Disulfide bridges form between cysteine and methionine amino acids.
 Salt bridges are interactions between the ends of the ions on an amino acid, the NH3+ and the COO-.
 Hydrophobic interactions are formed between those amino acids with hydrophobic R groups.
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Overall Tertiary Structure
showing:
Pink = alpha-helical area
Yellow = beta-sheet area
White/Blue = woven or turns area
The above picture shows an entire protein, this is called its tertiary structure. The tertiary structure
gives the protein its function. If the tertiary structure is deformed the protein will not function. The
primary structure is sequenced in a way as to form the tertiary structure. The side chains of the amino
acids cause them to interact with the other parts of the chain. These interactions include hydrogen
bonding, hydrophobic interactions, electrostatic interactions and van der Waals forces. An egg white is
all protein, when it comes out of the shell it is clear, when you cook the egg you destroy its Tertiary
Structure and the protein unfolds and becomes white, this destroys the proteins secondary, tertiary and
quaternary structures. The primary structure will normally stay intact if the food is cooked..
Some proteins have a quaternary structure. The quaternary structure occurs in proteins composed of
more than one peptide chain. Meaning two or more proteins come together to form one large protein.
We have mentioned hemoglobin a couple of time. This large protein has a quaternary structure as it is
composed of four myoglobin subunits. Each subunit is a separate polypeptide chain.
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Examining Proteins
• Primary structure
– amino acid sequence
SNHEEVADLLAQIQ
• Secondary structure
– alpha helices or beta sheets
• Tertiary structure
– disulfide bonds, H-bonds,
salt bridges
peptide
S
peptide
S
• Quaternary structure
– dimers, polymers, complexes
This picture is showing each of the four structure types and the order of their formation. First the
primary structure is formed, as this structure forms secondary structures take shape. Once the protein
sequence is completed the protein folds into its tertiary structure. If the protein has a quantanary
structure, two or more proteins will come together to complete the quantanary structure.
Destroying a Protein:
When a protein is destroyed it is said to be denatured. Remember that the purpose of a primary
structure is so the secondary and tertiary structures will form. Certain conditions will cause the protein
to unfold, leaving only the primary structure.
 heat – breaks hydrogen bonds by causing the atoms to vibrate too radically
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UV light – breaks hydrogen bonds by exciting bonding electrons
organic solvents – breaks hydrogen bonds
strong acids and bases – breaks hydrogen bonds and can hydrolyze the peptide bonds, breaking the
primary structure
detergents – disrupt hydrophobic interactions
heavy metal ions – forms bonds to sulfur groups and can cause proteins to precipitate out of solution.
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Essential and Non-Essential Amino Acids:
As far as your body is concerned, there are two different types of amino acids: essential and nonessential. Non-essential amino acids are amino acids that your body can create out of other chemicals
found in your body. Essential amino acids cannot be created, and therefore the only way to get them is
through food. Here are the different amino acids:
Non-Essential Amino Acids:
1. Alanine (synthesized from pyruvic acid)
2. Arginine (synthesized from glutamic acid)* essential for infants and young children
3. Asparagine (synthesized from aspartic acid)
4. Aspartic Acid (synthesized from oxaloacetic acid)
5. Cysteine (synthesized from homocysteine, which comes from methionine)
6. Glutamic Acid (synthesized from oxoglutaric acid)
7. Glutamine (synthesized from glutamic acid)
8. Glycine (synthesized from serine and threonine)
9. Proline (synthesized from glutamic acid)
10. Serine (synthesized from glucose)
11. Tryosine (synthesized from phenylalanine)
H O
NH2
C C OH
CH2
CH2
O C
H O O
H C C C OH
O
H
pyruvic acid
H
glutamic acid
H O
NH2
C C OH
CH2
O C
O H H O O
O H O O
O
HO C C C C OH HO C C
H
H
oxaloacetic acid
aspartic acid
H H
oxoglutaric acid
H O
H O
NH2
CH2OH
O
H
H
OH
HO
H
C C OH
H O
CH2
NH2
H
OH
H
HO
alpha -D-glucose
H O
phenylalanine
NH2
C C OH
NH2
C C OH
CH2
C C OH
H C OH
CH2
CH2
H C H
S
OH
serine
H
threonine
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C C C OH
CH3
methionine
H O
NH2
C C OH
CH2
CH2
SH
homocysteine
Essential Amino Acids:
1. Histidine
2. Isoleucine
3. Leucine
4. Lysine
5. Methionine
6. Phenylalanine
7. Threonine
8. Tryptophan
9. Valine
must be consumed
9 Essential Amino Acids: Function, Deficiencies and Excesses
HISTIDINE
Main Functions:
Found in high concentrations in hemoglobin.
Useful in treating anemia due to relationship to hemoglobin.
Has been used to treat rheumatoid arthritis.
Precursor to histamine.
Associated with allergic response and has been used to treat allergy.
Assists in maintaining proper blood pH.
Histidine Excess In:
Pregnancy
Histidine Deficiency Seen In:
Rheumatoid arthritis
Anemia
Dysbiosis (Imbalance of intestinal bacterial flora).
Note:
High Histidine levels are associated with low zinc levels. Low Histidine levels are associated with high
zinc levels. Thus, abnormal Histidine levels are an indicator that zinc levels should be tested.
ISOLEUCINE
Main Functions:
One of the 3 major Branched-Chain Amino Acids (BCAA), all of which are involved with muscle
strength, endurance, and muscle stamina.
Muscle tissue uses Isoleucine as an energy source.
Required in the formation of hemoglobin.
BCAA levels are significantly decreased by insulin. Translation: High dietary sugar or glucose intake
causes release of insulin, which, in turn, causes a drop in BCAA levels. Therefore, right before exercise, it
is not wise to ingest foods high in glucose or other sugars, as the BCAA's, including Isoleucine will not
be readily available to muscles.
Isoleucine Excess Seen In:
Diabetes Mellitus with ketotic hypoglycemia
Isoleucine Deficiency Seen In:
Obesity
Hyperinsulinemia
Panic Disorder
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Chronic Fatigue Syndrome (Note: Deficiencies in BCAA in CFS, GWS, FM are associated with muscle
weakness, fatigue, and post-exertional exhaustion).
Acute hunger
Kwashiorkor (starvation)
LEUCINE
Main Functions:
As one of the 3 branched-chain amino acids (the other 2 being Isoleucine and Valine), Leucine has all of
the properties discussed with Isoleucine, as it pertains specifically to the branched-chain amino acid
functions.
Potent stimulator of insulin.
Helps with bone healing.
Helps promote skin healing.
Modulates release of Enkephalins, which are natural pain-reducers.
Leucine Excess Seen In:
Ketosis
Leucine Deficiency Seen In:
Hyperinsulinemia
Depression
Chronic Fatigue Syndrome (Note: Deficiencies in BCAA in CFS, GWS, FM are associated with muscle
weakness, fatigue, and post-exertional exhaustion).
Acute hunger
Kwashiorkor (starvation)
Vitamin B-12 deficiency in pernicious anemia
LYSINE
Main Functions:
Inhibits viral growth and, as a result, is used in the treatment of Herpes Simplex, as well as the viruses
associated with Chronic Fatigue Syndrome, such as: Epstein-Barr Virus, CytoMegalo Virus, and HHV6.
L-Carnitine is formed from Lysine and Vitamin C.
Helps form collagen, the connective tissue present in bones, ligaments, tendons, and joints.
Assists in the absorption of calcium.
Essential for children, as it is critical for bone formation.
Involved in hormone production.
Lowers serum triglyceride levels.
Lysine Excess Seen In:
Excess of ammonia in the blood
Lysine Deficiency Seen In:
Herpes
Epstein-Barr Virus
Chronic Fatigue Syndrome
AIDS
Anemia
Hair loss
Weight loss
Irritability
METHIONINE
Main Functions:
Assists in breakdown of fats.
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Precursor of the amino acids Cysteine and Taurine.
Helps reduce blood cholesterol levels.
Antioxidant.
Assists in the removal of toxic wastes from the liver.
One of the sulfur-containing aminos (the others being Cysteine and the minor amino acid, Taurine). The
sulfur-containing amino acids act as anti-oxidants which neutralize free radicals.
Helps prevent disorder of hair, skin, and nails due to sulfur and anti-oxidant activity.
Precursor to Carnitine, Melatonin (the natural sleep aid) and Choline (part of the neurotransmitter,
Acetylcholine).
Involved in the breakdown of Epinephrine, Histamine, and Nicotinic Acid.
Required for synthesis of RNA and DNA.
Natural chelating agent for heavy metals, such as lead and mercury.
Methionine Excess Seen In:
Severe liver disease
Methionine Deficiency Seen In:
Chemical Exposure
Multiple Chemical Sensitivity (MCS)
Vegan Vegetarians
PHENYLALANINE
Main Functions:
Precursor to Tyrosine, which, in turn, is the precursor to the neurotransmitters: Dopamine and the
excitatory neurotransmitters Norepinephrine and Epinephrine.
Precursor to the hormone, Thyroxin.
Enhances mood, clarity of thought, concentration, and memory.
Suppresses appetite.
Major part of collagen formation.
While the L-form of all of the other amino acids is the one that is beneficial to people, the
D and DL forms of Phenylalanine have been useful in treating pain.
DL-Phenylalanine is useful in reducing arthritic pain.
Powerful anti-depressant.
Used in the treatment of Parkinson's Disease.
Phenylalanine Excessive Seen In:
Pregnancy
pigmented melanoma
PKU (phenylketonuria)
panic disorder/anxiety attacks.
Phenylalanine Deficiency Seen In:
Depression
Obesity
Cancer
AIDS
Parkinson's Disease
Note:
Phenylalanine should be avoided if you suffer from High blood pressure, as it has hypertensive.
THREONINE
Main Functions:
Required for formation of collagen.
Helps prevent fatty deposits in the liver.
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Aids in production of antibodies.
Can be converted to Glycine (a neurotransmitter) in the central nervous system.
Acts as detoxifier.
Needed by the GI (gastrointestinal) tract for normal functioning.
Provides symptomatic relief in ALS (Amyotrophic Lateral Sclerosis, Lou Gehrig's Disease).
In laboratory experiments with animals, Threonine increases thymus weight.
Threonine is often low in depressed patients. In that group of patients, Threonine is helpful in treating
the depression.
Threonine Excess Seen In:
Alcohol ingestion
Those treated with sedative anti-convulsing medication (animal studies)
Vitamin B6 deficiency
Pregnancy
Liver cirrhosis
Threonine Deficiency Seen In:
Depression
AIDS
Muscle Spasticity
ALS (Amyotrophic Lateral Sclerosis)
Vegetarianism
Epilepsy
TRYPTOPHAN
Main Functions:
Precursor to the key neurotransmitter, serotonin, which exerts a calming effect.
Effective sleep aid, due to conversion to serotonin.
Reduces anxiety.
Effective in some forms of depression.
Treatment for migraine headaches.
Stimulates growth hormone.
Along with Lysine, Carnitine, and Taurine is effective in lowering cholesterol levels.
Can be converted into niacin (Vitamin B3).
Lowers risk of arterial spasms.
The only plasma amino acid that is bound to protein.
Tryptophan must compete with 5 other amino acids to pass through the blood-brain barrier and enter
the brain. Those 5 are: tyrosine, phenylalanine, leucine, isoleucine, and valine and are called Large
Neutral Amino Acids (LNAA).
Requires pyridoxal-5-phosphate (P5P) a form of vitamin B6 to be converted into serotonin. P5P
deficiency will lower serotonin levels, even if Tryptophan levels are normal.
Tryptophan Excess Seen In:
Increased intake of salicylates (aspirin).
Increased blood levels of free fatty acids.
Sleep deprivation.
Niacin intake.
Tryptophan Deficiency Seen In:
Depression
Insomnia
Chronic Fatigue Syndrome
ALS
FDA ban of Tryptophan
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Note:
Simultaneous treatment with Tryptophan and Prozac (and other SSRI anti-depressants, such as Paxil and
Zoloft) can produce an irreversible brain disorder called Serotonin Syndrome. This treatment
combination is to be avoided.
Standard AMA, APA (American Psychiatric Association), FDA, and pharmaceutical industry position
has been that Tryptophan is not an effective treatment of serotonin-depletion depressions, when
compared to Prozac and other SSRI's.
Clinical experience has shown that some people respond well to Prozac while others respond well to
Tryptophan in treating serotonin-depleted depressions. When the FDA banned Tryptophan, thousands
of people who only had a positive response to Tryptophan (and not to Prozac) decompensated
psychologically and never recovered.
Tryptophan is again available, but only through prescription and compounding pharmacies.
VALINE
Main Functions:
One of the 3 major Branched-Chain Amino Acids (BCAA) . . .the other 2 being leucine and isoleucine . . .
all of which are involved with muscle strength, endurance, and muscle stamina.
BCAA levels are significantly decreased by insulin. High dietary sugar or glucose intake causes release
of insulin, which, in turn, causes a drop in BCAA levels.
Competes with Tyrosine and Tryptophan in crossing the blood-brain barrier. The higher the Valine level,
the lower the brain levels of Tyrosine and Tryptophan. One of the implications of this competition is that
Tyrosine and Tryptophan nutritional supplements need to be taken at least an hour before or after meals
or supplements that are high in branched chain amino acids.
Actively absorbed and used directly by muscle as an energy source.
Not processed by the liver before entering the blood stream.
Any acute physical stress (including surgery, sepsis, fever, trauma, starvation) requires higher amounts
of Valine, Leucine and Isoleucine that any of the other amino acids.
During period of Valine deficiency, all of the other amino acids (and protein) are less well absorbed by
the GI tract.
Valine Excess Seen In:
Ketotic Hypoglycemia
Visual and tactile hallucinations
Valine Deficiency Seen In:
Kwashiorkor
Hunger
Obesity
Neurological deficit
Elevated insulin levels
Metabolism:
An adult daily calories calculator gives an approximation of your basal metabolic rate - the number of
calories per day your body burns.
If your goal is to lose weight by burning off excess body fat, aim to eat 500 fewer calories per day than
your daily caloric needs, and maintain or increase your exercise activity. Do not go below 1200 calories
per day unless you are on a medically supervised weight loss program or after consultation with your
doctor.
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Questions to ask yourself:
How many calories do I need?
How many grams of carbohydrates, fats, and protein do I need?
How many servings of each food group do I need?
What are the recommended nutrients that I need?
What are some supplements that I can take?
http://walking.about.com/cs/calories/l/blcalcalc.htm
For example: a female, my age, weight, and activity level needs about 2000 calories a day.
Protein is made up of chains of amino acids, some of which our bodies cannot manufacture. Protein is
essential for building and maintaining muscles, as well as repairing the muscle damage that occurs
during training. Protein is also needed to make red blood cells, produce hormones, boost your immune
(disease-fighting) system, and help keep hair, fingernails, and skin healthy. Athletes who are protein
deficient may complain about having hair that falls out easily and fingernails that grow slowly and
break easily. Female athletes who eat a protein-poor diet may also stop having periods.
Protein Nutrition:
Protein in our diets comes from both animal and vegetable sources. Most animal sources (meat, milk,
eggs) provide what's called "complete protein," meaning that they contain all of the essential amino
acids. Vegetable sources usually are low on or missing certain essential amino acids. For example, rice is
low in isoleucine and lysine. However, different vegetable sources are deficient in different amino acids,
and by combining different foods you can get all of the essential amino acids throughout the course of
the day. Some vegetable sources contain quite a bit of protein -- things like nuts, beans, soybeans, etc. are
all high in protein. By combining them you can get complete coverage of all essential amino acids.
The digestive system breaks all proteins down into their amino acids so that they can enter the
bloodstream. Cells then use the amino acids as building blocks.
From this discussion you can see that your body cannot survive strictly on
carbohydrates. You must have protein. According to this article, the RDA
(Recommended Daily Allowance) for protein is 0.36 grams of protein per pound of
body weight. So, a 150-pound person needs 54 grams of protein per day.
Athletes will need more in their diets. Many studies have recommended protein
levels of 1 gram of protein per kilogram of body weight per day. Which is near
three times that of a non-active person.
The nutritional facts picture is the Nutritional Facts label from a package of
bacon. You can see that a serving of this bacon has 4 grams of protein. There are
9 servings in this package giving a total of 36 grams of protein. An 8 ounce glass
of milk contains about 8 grams of protein. A slice of whole grain bread may
contain 2 or 3 grams of protein. You can see that it is not that hard to meet the
RDA for protein with a normal diet. A fried egg will have about 8 grams of protein. So, a typical
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breakfast may consist of 2 fried eggs, 2 pieces of toast and a glass of milk giving you about 30 grams
of protein just for breakfast. A 150 lb person is well on their way to meeting their RDA of 54 grams
of protein.
Food
Protein Content of Foods
cocoa powdered
wheat
fried egg
cod
salmon
lobster
tuna
chicken
hamburger
filet mignon
salami
gelatin
parmesan
Cheedar
fresh skim milk
dried skim milk
almonds
peanuts
mustard
sesame seeds
peanut butter
vegemite
chickpeas
soy
caramel
0
10
20
30
40
50
60
70
80
grams protein per 100 grams food stuffs
How much protein do athletes need?
There isn't an exact number for athletes because protein needs vary, depending on whether an athlete is
growing, rapidly building new muscle, doing endurance exercise, or dieting, in which case protein is
used as a source of energy (table 1). Protein requirements for athletes are higher than the current
recommended dietary allowance (RDA) of 0.4 g of protein per pound of body weight, which is based on
the needs of nonexercisers. Protein recommendations for athletes are commonly expressed in a range to
include a safety margin. If you do the math (1g of protein has 4 calories), you will see that you do not
need to have 30% of your calories come from protein.
Table 1. Recommended Grams of Protein Per Pound of
Body Weight Per Day*
RDA for sedentary adult
0.4
Adult recreational exerciser
0.5-0.75
Adult competitive athlete
0.6-0.9
Adult building muscle mass
0.7-0.9
Dieting athlete
0.7-1.0
Growing teenage athlete
0.9-1.0
*To find your daily protein requirement, multiply the
appropriate numbers in this table by your weight in
pounds.
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90
Vegetarian athletes can eat enough protein to satisfy their bodies' needs if they wisely choose plant
proteins. Lacto-ovo vegetarians (who eat eggs, milk, yogurt, cheese, and other dairy foods but no meat)
can most easily consume adequate protein because these foods are excellent sources of life-sustaining
protein and contain all the essential amino acids.
The key for total vegetarians, or vegans (who eat no milk, eggs or other animal proteins), is to eat a
variety of grains that have complementary amino acids. For example, beans and rice is an example of
mixing legumes (peas and beans) and grains. Also, tofu is an excellent addition to a vegetarian diet. Tofu
has made headlines because it is a high-quality plant protein that contains all essential amino acids and
offers the bonus of phytochemicals that protect against heart disease and cancer.
The main function of carbohydrates (any of a group of chemical compounds, including sugars, starches,
and cellulose, containing carbon, hydrogen, and oxygen only) is for energy in the body. Carbohydrates
are the preferred fuel for the body, so you want a majority of total calories coming from carbohydrate. In
the absence of carbohydrates, protein is broken down to provide needed energy - which could lead to a
protein deficiency, and loss of lean body mass. In cases of extreme exercise, starvation or high protein,
low carbohydrate diets, a deficiency may occur. If intake of carbohydrate is in excess of total energy
needed by the body, the excess carbohydrate will be stored as fat. It is best to try to consume more
complex carbohydrates, and less simple sugars.
recommendation: there is no set recommendation for carbohydrates, but an intake of at least 50-100 g
per day is needed. It is recommended that 50-60% of total calories come from carbohydrate, with no
more than 10% of those calories coming from simple sugars.
foods in (complex sources): whole grains, breads, pastas, rice, cereals, starchy vegetables such as
potatoes, corn, lima beans, kidney beans, and baked beans. Simple sugars include sugar, candy, high
fructose corn syrup, soda, jelly, and honey.
Everyone Needs to Eat More Fruits and Vegetables
A growing body of research proves that fruits and vegetables are critical to promoting good health. In
fact, fruits and vegetables should be the foundation of a healthy diet. Most people need to double the
amount of fruits and vegetables they eat every day.
Fruits and Vegetables and
Weight Management
Because they're low in calories and high in fiber, fruits and vegetables can help you control your weight.
By eating more fruits and vegetables and fewer high-calorie foods, you'll find it much easier to control
your weight.
Fruits and Vegetables Contain Powerful Phytochemicals (fight-o-chemicals)
Fruits and vegetables have many important phytochemicals that help "fight" to protect your health.
Phytochemicals are usually related to color. Fruits and vegetables of different colors — green, yelloworange, red, blue-purple, and white — contain their own combination of phytochemicals and nutrients
that work together to promote good health. Phytochemicals and the colors of health:
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A phytochemical (fight-o-chemical) is a natural
bioactive compound found in fruits and
vegetables that works together with vitamins,
minerals, and fiber to promote good benefit your
health in many ways. The bioactive functions of
phytochemicals — or the way they work in your
body — is an ongoing area of research.
Remember, only fruits and vegetables, not pills or
supplements, can give you phytochemicals and
nutrients in the healthy combinations nature intended.
When you eat fruits and vegetables, nutrients are
easily absorbed to provide maximum health benefits.
In contrast, supplements or pills contain large doses
of only one or a couple of phytochemicals. These
isolated supplements have not been proven to
be effective or even safe.
For example, some studies show that
phytochemicals can:

Act as antioxidants

Stimulate detoxification enzymes

Stimulate the immune system

Positively affect hormones

Act as antibacterial or antiviral agents
Phytochemicals are usually related to the color of
fruits and vegetables — green, yellow-orange, red,
blue-purple, and white. Hundreds of
phytochemicals have been discovered. You can
benefit from all of them by eating 5 to 9 servings
of colorful fruits and vegetables everyday.
Eat a Variety of Fruits and Vegetables:
By eating a variety of colorful fruits and vegetables — green, yellow-orange, red, blue-purple, and white
— you're giving your body a wide range of nutrients that are important for good health. Each color
offers something unique, like different vitamins, minerals, and disease-fighting phytochemicals, that
work together to protect your health. Only fruits and vegetables, not pills or supplements, can give you
these nutrients in the healthy combinations nature intended. Here are some examples:
18
Color
Sources of
Found in
Green
Lutein and
Zeaxanthin
Turnips, Collard, and
Mustard greens, Kale, Spinach,
Lettuce, Broccoli, Green Peak,
Kiwi, Honeydew Melons
Indoles
Broccoli, Cabbage, Brussel
Sprouts, Bok Choy, Arugula,
Swiss Chard, Turnips, Rutabaga,
Watercress, Cauliflower, Kale
Vitamin K
Swiss Chard, Kale, Brussel
Sprouts, Spinach, Turnip greens,
Watercress, Endive, Lettuce,
Mustard greens, Cabbage
Potassium
Leafy greens, broccoli
Yellow/Orange
Beta-Carotene &
Vitamin A
Carrots, Sweet potatoes, Pumpkin,
Butternut Squash, Cantaloupe, Mangoes,
Apricots, Peaches
Bioflavonoids &
Vitamin C
Oranges, Grapefruit, Lemons, Tangerines,
Clementines, Peaches, Papaya, Apricots,
Nectarines, Pears, Pineapple, Yellow
Raisins, Yellow Pepper
Potassium
Bananas, Oranges, Grapefruit, Lemons,
Pineapple, Apricots
Vitamin C
Cranberries, Pink grapefruit, Raspberries,
Strawberries, Watermelon, Red Cabbage,
Red Pepper, Radishes, Tomatoes
Anthocyanins
Raspberries, Cherries, Strawberries,
Cranberries, Beets, Apples, Red Cabbage,
Red Onion, Kidney Beans, Red Beans
Red
19
Blue/Purple
Anthocyanins &
Vitamin C
Blueberries, Blackberries, Purple Grapes,
Black Currants, Elderberries
Phenolics
Dried Plums (Prunes), Raisins, Plums,
Eggplant
Allium & Allicin
Garlic, Onions, Leeks, Scallions, Chives
White
Heart Disease
Heart-healthy diets are rich in fruits and vegetables (8 to 10 servings a day), low in saturated fat and
cholesterol, and emphasize low-fat dairy foods and whole grains. Such diets can significantly lower
blood pressure and cholesterol levels and may reduce the risk for having heart disease.
High Blood Pressure
According to the Dietary Approaches to Stop Hypertension (DASH) Study, when people with elevated
blood pressure followed an eating plan that emphasizes fruits and vegetables (8 to 10 servings a day)
and low-fat dairy foods (2 to 3 servings a day) as part of a healthy diet low in saturated fat, cholesterol,
and total fat, they lowered their blood pressure within a month. In addition, those who had the lowest
sodium intake had the greatest fall in blood pressure.
The DASH study also showed the eating plan to be beneficial for people with hypertension and those
wishing to prevent high blood pressure. In addition to being rich in fruits and vegetables (8 to 10
servings a day) and emphasizing low-fat dairy foods (2 to 3 servings a day), the DASH eating plan also
includes moderate amounts of whole grains, fish, poultry and nuts and limited amounts of red meat,
sweets, and sugar-containing beverages. For details regarding the DASH eating plan download the pdf
file on the webpage.
Type II Diabetes
Obesity and diet are strong risk factors for developing type 2 diabetes. Therefore, it is important to stay
at a healthy weight by getting adequate physical activity and eating a healthy diet that includes daily
recommended servings of fruits and vegetables.
20
Certain Cancers
People whose diets are rich in fruits and vegetables (5 to 9 servings a day) have a lower risk of getting
cancers of the lung, mouth, pharynx, esophagus, stomach, colon, and rectum. They are also less likely to
get cancers of the breast, pancreas, ovaries, larynx, and bladder. There is no specific fruit or vegetable
responsible for reducing cancer risk; instead, research shows that it is the regular consumption of a
variety of fruits and vegetables that reduces risk.
An expert report, Food, Nutrition and the Prevention of Cancer: a Global Perspective, reviewed over 4,500
world-wide research studies and found that if people increased their fruit and vegetable consumption to
at least five servings a day, cancer rates could be reduced by more than 20 percent.
Serving Sizes
One serving of fruits and vegetables should fit within the palm of your hand —
it's a lot smaller than most people think.
The palm of your hand is an easy way to think about serving sizes and to see
how doable it is to eat 5 to 9 A Day, everyday.
If you measure it out, one serving is:
A small glass of 100% fruit or vegetable juice (3/4 cup or 6 oz)
A medium-size piece of fruit
(an orange, small banana, medium-size apple)
One cup of raw salad greens
1/2 cup of cooked vegetables
1/2 cup of cut-up fruit or vegetables
1/4 cup of dried fruit
1/2 cup of cooked beans or peas
Introduction:
Carbohydrates are normally the first classification of compounds to be discussed which fall within the
realm of Biochemistry. All biological systems are run on chemical reactions: some are easy to see, such
as the iron ion needed to hold oxygen in red blood cells. The positively charged iron attracts the lone
pairs of electrons on the oxygen molecule. HCl in the stomach breaks down many large molecules
allowing the small intestines digest more manageable pieces.
The three main classes of molecules metabolized by our bodies:
1. Carbohydrates (sugars)
2. Lipids (fats)
3. Proteins (amino acids)
21
Carbohydrates are defined as sugars and their derivatives. Animals (such as humans) break down
carbohydrates during the process of metabolism to release energy. For example, the chemical
metabolism of the sugar glucose is shown below:
glucose + oxygen  carbon dioxide + water + energy
C6H12O6 + 6 O2  6 CO2 + 6 H2O + Energy
Animals obtain carbohydrates by eating foods that contain them, for example potatoes, rice, breads, etc.
These carbohydrates are manufactured by plants during the process of photosynthesis. Plants harvest
energy from sunlight to run the reaction described above in reverse:
6 CO2 + 6 H2O + energy (from sunlight)  C6H12O6 + 6 O2
A potato, for example, is primarily a chemical storage system containing glucose molecules
manufactured during photosynthesis. In a potato, however, those glucose molecules are bound together
in a long chain. As it turns out, there are two types of carbohydrates, the simple sugars and those
carbohydrates that are made of long chains of sugars - the complex carbohydrates.
The simplest carbohydrates are the monosaccharide, a single unit simple sugar.
The most common monosaccharide is glucose, and this is the most important one for living organisms.
Metabolism:
Processes require energy. The term metabolism is associated with energy. This is just one aspect of
metabolism.
Metabolism more specifically refers to a sequence of chemical reactions used to produce one or more
products or accomplished one or more processes.
Returning to energy, per gram fats provide the most energy, carbohydrates provide the next most and
proteins provide the least energy. The energy of carbohydrates is the most quickly utilized. Think about
a 4 year old after sneaking into their Halloween candy bag. They are full of energy!
Structure of Carbohydrates:
Lets break down the word carbohydrate. Carbo = carbon and hydrate = water leading one to believe
carbohydrates are hydrates of carbon. Remember a hydrate is a compound which has water loosely
attached. An example would be FeCl3  6 H2O. This is iron(III) chloride hexahydrate. Each FeCl3 salt
molecule has absorbed 6 water molecules. These are not chemically bound and can be removed by
heating leaving FeCl3 and H2O. Since the chemical formulas are unchanged there has been no chemical
reaction, it has undergone a physical process.
H
C O
H C OH
H C OH
H C OH
H C OH
H
Ribose
22
Carbohydrate Polymer:
Carbohydrates are also referred to as saccharides. Saccharides can be found in several forms.
single
pair
many
monosaccharide
disaccharide
polysaccharide
monosaccharide
 basic unit of metabolism
 normally 3, 4, 5, 6 or 7 carbons in length
 classified as aldose or ketose
 classified as D or L isomers based on the stereochemistry
disaccharide
 use to transport monosaccharides
 water soluble – as they are short hydrocarbon chains
 are sweet to taste
 sucrose, galactose and lactose
polysaccharides
 structure of plants – cellulose
 storage of monosaccharides
Importance of Carbohydrates:
 Very effective energy yield
o contains carbon
o has a reactive bond – carbonyl carbon and is a polar area
o does not have 4 bonds to oxygen – which means the carbon is organic carbon, remember that
organic carbon is carbon with an low oxidation number, once the oxidation number becomes
+4 it can no longer be oxidized
 Effective building material
o strong not brittle – will bend and not break
 H2O soluble
o easily transported thru the blood stream
o easily passes thru cell walls
 Sugars are carbohydrates.
 Sucrose was used as the standard, all other sugars sweetness is based on sucrose.
carbohydrate
sucrose
lactose
maltose
glucose
galactose
fructose
relative
sweetness
1.00
0.16
0.32
0.74
0.22
1.74
class
disaccharide
disaccharide
disaccharide
monosaccharide
monosaccharide
monosaccharide
23
common
name
table sugar
milk sugar
malt sugar
blood sugar
fruit sugar
Saccharide Monomers: (important)
Glucose
 classified as an aldohexose – as it is an aldehyde and a 6-carbon compound
 Most carbohydrates are converted to glucose to be metabolized for energy.
 dextrose and blood sugar are both common names for glucose
 one of the monomers found in the disaccharide: found in sucrose, maltose and lactose
 a monomer of starch, cellulose and glycogen
 25% less sweet than table sugar, sucrose
 no digestion needed can be given intravenously
 found in the urine of diabetics
 70-150mg per ml of blood
H
HO
H
HO
H
H
C O
C O
OH
H
H
HO
OH
H
OH
H
OH
H
H
OH
CH2OH
CH2OH
L-glucose
D-glucose
Galactose






classified as an aldohexose – as it is an aldehyde and a 6-carbon compound
found in pectin and gum
combined with glucose to form the disaccharide lactose
80% less sweet than table sugar, sucrose
Galactosemia
o genetic disease – inability of body to metabolize galactose
o elevated levels of galactose in blood and urine
o vomiting, diarrhea, liver enlargement
o can cause death in days
o lactose must be removed from their diet
o http://www.galactosemia.org/galactosemia.htm
isomer (same formula, different structure) of glucose (carbon #5 is different!)
24
H
H
H
C O
C O
H
OH
HO
H
HO
H
HO
H
carbon #5
OH
HO
H
HO
H
H
carbon #5
OH
CH2OH
CH2OH
D-galactose
L-galactose
Fructose





classified as a ketohexose as this molecule is a ketone and is a 6-carbon chain
found in fruit juice and honey
combined with glucose to form the disaccharide sucrose
175% sweeter than table sugar, sucrose
this country’s most common sweetener
o high fructose corn syrup
o can be metabolized to glucose in the liver
HO
H
HO
CH2OH
CH2OH
C O
C O
H
HO
H
OH
H
OH
H
H
OH
CH2OH
CH2OH
L-fructose
D-fructose
Cyclic Saccharides:
The straight form of saccharides is very reactive. For the saccharide to be stable enough to transport and
not used by the body immediately, it forms a cyclic structure. Below are drawings for the formation of
straight-chained glucose to become cyclic. The reaction breaks the double bond of the carbonyl group
and shifts hydrogen of the hydroxyl group on the number 5 carbon to the carbonyl group’s oxygen.
H
C O
H
OH
HO
carbon 5
H
H
OH
H
O H
H C OH
H
D-glucose
25
carbon 6
carbon 5
CH2OH
CH2OH
C
O
carbon 4
H
C
H
OH
C
HO
H
carbon 1
H
C
H
C
O
H
H
OH
OH
H
carbon 2
HO
H
HO
OH
H
HO
carbon 3
This ring structure will also form with the ketose saccharides like fructose.
CH2OH
C O
HO
HOH2C
CH2OH
O
H
H
OH
H
O H
H
H
OH
CH2OH
HO
OH
H
-D-fructose
D-fructose
As such other prefixes, new ones must be introduced to describe the stereochemistry (the location of
groups on a molecula): alpha,  and beta, . Below is the cyclic structure of glucose. The carbon to the
far right on each ring shows the hydroxyl group in different location. The alpha structure has the
hydroxyl group down and the beta group has the hydroxyl group up.
CH2OH
CH2OH
O
H
H
OH
H
HO
H
OH
O
H
H
OH
H
H
HO
HO
OH
H
-D-glucose
HO
-D-glucose
26
H
These are the straight and cyclic structures for fructose:
carbon 6
CH2OH
C O
H
OH
H
OH
H
OH
HOH2C
H
carbon 5
carbon 2
HO
H
CH2OH
OH
O
CH2OH
H
OH
carbon 1
carbon 4 carbon 3
D-fructose
D-fructose
Below are the two rings of fructose. The alpha is on the left, hydroxyl on the down. The beta on the
right, hydroxyl on the top.
HOH2C
H
HO
H
HOH2C
CH2OH
O
H
-D-fructose
CH2OH
H
OH
H
OH
HO
H
OH
OH
O
-D-fructose
These are the straight and cyclic structures for ribose, a six carbon aldose.
H
C O
H
OH
H
OH
H
OH
HOH2C
H
H
H
OH
CH2OH
OH
O
H
OH
Below are the two ring structures of ribose. The alpha is on the left, hydroxyl on the down. The beta on
the right, hydroxyl on the top.
HOH2C
H
H
OH
HOH2C
H
O
H
H
H
OH
OH
OH
-D-ribose
OH
O
H
OH
-D-ribose
27
H
Note: the R in RNA is from ribonucleic acid. The D in DNA is a molecule whose structure is very close
to that of ribose; the molecule is deoxyribonucleic acid. Lets break down that word. The prefix “de“
means loss, “oxy” means oxygen and “ribo” refers to ribose. So, what you have is a ribose that has lost
an oxygen.
HOH2C
H
H
H
OH
HOH2C
OH
O
H
H
H
OH
OH
ribose
OH
O
H
H
H
deoxyribose
This may not seem like much of a change, but this demonstrates the specificity of chemistry. One
oxygen can change the function of a molecule from making proteins, RNA, and storing the organism
genetic information, DNA. Both of the above molecules are furanose, 5-member rings and are in the beta
form, the hydroxyl is up.
Disaccharides:






The three most important disaccharides are sucrose, lactose and maltose.
The monomers are very specific. Meaning you must have stereochemistry exact, the bond will
require an alpha or beta and always the D form.
Disaccharides are formed thru a dehydration reaction.
This reaction releases a water molecule.
To break this bond, named a glycosidic bond, you add water, this reaction is named hydrolysis.
Where in your body will this digestion occur?
Sucrose:











most common disaccharide, table sugar
20% of sugar cane is sucrose
based on the total consumption in this country, it is estimated that a person will consume 100 pounds
of sucrose each year
it is composed of one -D-glucose and one -D-fructose monomer
not a reducing sugar therefore no reaction occurs with the Benedict’s reagent
this reaction will not occur because there is no way to open ring and form an aldehyde
in an acidic solution sucrose undergoes hydrolysis, the resulting solution containing glucose and
fructose is sweeter than the original sucrose
this can be observed in jams and jellies, the acid in the fruit’s juice, normally citric acid, causes the
sucrose to undergo hydrolysis
linked -1  -2
this linkage information tells you that the -D-glucose molecule uses its #1 carbon, whose OH group
is down, to bond to the #2 carbon on the -D-fructose molecule, whose OH group is up
the reaction and structures are drawn below
28
CH2OH
O
H
H
OH
4
CH2OH
-D-glucose
H
1
OH
H
HO
H
H
O
HO
HOH2C
O
2
H
OH
O
H
1
HO
H2O
HOH2C
H
OH
4
H
HO
O
H
HO
H
CH2OH
1
H
H
2
HO
1
OH
H
OH
CH2OH
sucrose
H
-D-fructose
Lactose:







milk sugar
by mass composes 7% of human milk, 5% of bovine milk
being lactose intolerant is a fairly common condition, especially in adults who drink less milk, the
body forgets how to make the enzyme, lactase, needed to break apart the bonds in lactose
it is composed of one -D-glucose or -D-glucose and one -D-galactose monomer
Lactose is odd in the fact that the second monomer can have either  or  stereochemistry
in an acidic solution lactose undergoes hydrolysis, the resulting solution containing glucose and
galactose
the dehydration of one -D-glucose and one -D-galactose monomer forms water and lactose (the
reaction seem below)
-D-glucose
CH2OH
O
H
4
-D-galactose
4
OH
O
H
OH
1
OH
H
HO
CH2OH
1
H
H
H
H
H
HO
CH2OH
HO
H
OH
O
H
H
4
CH2OH
O
HO
HO
H2O
4
H
OH
H
H
29
HO
H
1
H
OH
O
1
H
H
OH
H
H
lactose
HO
Maltose:
 malt sugar
 it is composed of -D-glucose monomers
 in an acidic solution maltose undergoes hydrolysis, the resulting solution containing glucose
CH2OH
CH2OH
-D-glucose
O
H
4
H
OH
1
4
H
HO
H
OH
H
HO
CH2OH
H
O
H
H
1
HO
H
1
H
O
H
H
OH
HO
CH2OH
4
H
OH
HO
OH
H
O
H
H
-D-glucose
4
O
H
OH
1
H2O
H
OH
H
HO
H
HO
maltose
Polysaccharides:
Starch:
There are 2 classes of starch, animal and plant. amylose and amylopectin are in plant starch; glycogen is
in animal starch;.
Plant starch is the major storage carbohydrate (polysaccharide) in higher plants, being the end product
of photosynthesis. Starch is composed of a mixture of two polymers, an essentially linear polysaccharide
-amylose, and a highly branched polysaccharide - amylopectin. Starch is unique among carbohydrates
because it occurs naturally as discrete granules (or grains). Starch granules are relatively dense, insoluble
and hydrate (take on water) only slightly in cold water.
Amylose - The constituent of starch. The level of amylose and its molecular weight vary between
different starch types. Amylose molecules are typically made from 200-2000 units. Aqueous solutions of
amylose are very unstable due to intermolecular attraction and association of neighboring amylose
molecules. This leads to viscosity increase (resistance to flow), retrogradation and, under specific
conditions, precipitation of amylose particles. This is the starch you think of in a potato.
30
Animal Starch, glycogen, is a polymer of glucose. This is stored in the liver and is used for quick
energy. Glycogen can be quickly hydrolyzed (loses on water) to form glucose and is then deposited into
the blood stream for transport to cells. Glycogen is highly branched.
31
Cellulose:
Cellulose is yet a third polymer of the monosaccharide glucose. The below diagram is of a portion of a
cellulose chain. The glucose monomers are connected by a linkage, and this prevents most organisms,
including humans, from breaking the glucose monomers apart. Cellulose, also known as plant fiber,
cannot be digested by human beings and so cellulose passes through the digestive tract without being
absorbed into the body. Some animals, such as cows and termites, contain bacteria in their digestive
tract that help them to digest cellulose. Cellulose is a relatively stiff material, and in plants cellulose is
used as a structural molecule to add support to the leaves, stem and other plant parts.
Despite the fact that it cannot be used as an energy source in most animals, cellulose fiber is essential in
the diet because it helps exercise the digestive track and keep it clean and healthy.
Cellulose gives plants their structure, in their cell walls, for example wood fiber. It is also insoluble.
Cellulose differs from starch and glycogen because the glucose units form a two-dimensional structure,
with hydrogen bonds holding together nearby polymers, thus giving the molecule added stability
(shown in the smaller diagram in the upper right hand corner of the diagram below).
Artificial Sweeteners:
These sweeteners are normally used to reduce a person’s the caloric intake. They work two
ways. First, your body will not be able to metabolize the molecule, even though it can taste it.
So it passes right thru you. Second, the artificial sweeteners are much sweeter, so you need
much less than you would for conventional sugars.
For example Sucralose, the newest artificial sweetener is approximately 6000 times sweeter than
sucrose. Meaning you would need 6000 times less Sucralose than sucrose.
Sucralose taste a lot like sucrose, because it is made from sucrose. Below is the structure of
each.
32
CH2OH
Cl
CH2OH
O
H
OH
H
O
H
H
OH
H
H
H
H
HO
H
HO
O
CH2Cl O
H
H
OH
H
HOH2C
HO
CH2Cl
H
HO
O
O
H
H
HO
OH
Sucralose
CH2OH
H
sucrose
Lipids are a group of molecules which include: fats, oils, waxes, phospholipids, steroids (like
cholesterol), sphingolipids, and prostaglandins.


The main purpose of lipids is to store energy.
Other very important functions include:
o padding for organs
o dissolving fat soluble vitamins
o steroids – used in messaging, decomposition of large molecules, hormones..
o transportation of some molecules through the blood
o cell membrane structure
These molecules perform different functions in an organism. We will begin with fats, oils and
waxes.
Before we discuss lipids we should discuss a specific carboxylic acid, the fatty acid and esters. The
functional groups for each are shown below:
O
R C OH
carboxylic acid
O
R C O R
ester
A fatty acid is simply a carboxylic acid in which the R group is very long. It consists of many carbons
chained together with hydrogens completing their octet.
O H H H H H H H H H H H H H H H
HO C C C C C C C C C C C C C C C C H
H H H H H H H H H H H H H H H
palmitic acid - a fatty acid
33
Again, the main purpose of fats and oil is to store energy. Hence if you eat more calories than your body
needs, you turn these extra calories into fat for storage. This is a very basic need; the more fat an
organism can generate the more likely that organism will survive in times of low food supply. These
days this seemingly good genetic trait has lost its usefulness. A person trying to lose weight (fat) is
fighting against millions of years of evolution. They are fighting against their own genes; the genes that
allowed their ancestors to survive and eventually create them. If you think about it, the battle of the
bulge is really a battle against the survival of the strong. Darwin would be so upset. Or maybe not, if we
look at the genes being passed down what trend will be observed over the next millennia, thinner
people. People with bodies more adapted to a sedentary life.
Fatty acids come in two main classes, saturated and unsaturated. Saturated, indicates that the carbon
has as many hydrogens as possible bonded to said carbons, all single bonds, no double or triple.
Unsaturated, indicates that hydrogens could be added to the carbon chain, for instance in an addition
reaction across a double or triple bond. The palmitic acid shown above is a saturated fatty acid. Below
is a picture of an unsaturated fatty acid:
O H H H H H H
H H H H H H H H
HO C C C C 4 C 5 C C 7
1
2
3
10C
6
H H H H H H
8
9
12
H H H H H H H H
C C
H
C C 13 C 14C 15C 16C C 17H
11
H
As you can see the carbons have been numbered. It is important to know the location of the double bond
as the use of the fatty acid will vary depending on the location of this double bond. Further more the
nutritional value of the fatty acid is dependant on the location of the double bond.
Common names have been also developed; certain fatty acid names have been popularized by the
media. The acids can be named for how far the double bond lays away from the final tail carbon.
Linolenic acid has a double bond, three carbons from the fatty acid’s end. It is classified as an omega-3
fatty acid, the omega carbon being the terminal carbon and the bond being found on the third carbon
from the end. Linoleic acid is an omega-6 fatty acid. Of all the unsaturated fatty acids the body utilizes,
these two are considered essential fatty acids, as the body can not synthesize these. They must be
consumed to fill the body’s needs. Linoleic and linolenic acids are both polyunsaturated fatty acids,
meaning they have more than one carbon-carbon double bond and they both contain 18 carbons.
34
35
Fat, oil and wax are made from two kinds of molecules: glycerol (a type of alcohol with a OH group on
each of its three carbons) and three fatty acids joined by a dehydration reaction.
O
HO C
CH2
OH
O
CH
OH
HO C
CH2
OH
O
glycerol
HO C
3 stearic acid molecules
O
CH2 O C
O
CH O C
O
CH2 O C
triglyceride
The triglyceride molecule is the body’s storage molecule for fatty acids. The fatty acid, stearic acid, in
the triglyceride above is the energy storage molecule used by steer. If you eat a steak this is a molecule
floating through your veins.
Below you will find a triglyceride. But there is a major difference between the triglyceride below and the
one above. The double bond in the third fatty acid changes the structure of this molecule. This causes
the molecule to kink, and makes it turn. This keeps the molecule from laying on a neighboring molecule
closely. The molecules simply can not pack as close together. This keeps the molecules from being able
to form bonds with each other. This is the main difference between an oil and a fat. The fats have more
intermolecular forces being exerted between each other. This causes them to be a solid at room
temperature.
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Sphingolipids are the coating for nerve axons, myelin. The sphingolipid is not a derivative of glycerol.
The structure of the sphingosine is drawn below. Once a fatty acid and a phosphate with an attached
choline have bonded to the sphingosine, the sphingomyelin is created.
OH
OH
CH3(CH2)12CH CH C H
H2N C H
CH3(CH2)12CH CH C H
fatty acid
C NH C H
O
CH2OH
O
CH2O P O CH2CH2N(CH3)3
O
sphingosine
sphingomyelin
Without a proper myelin cover the nerves function erratically or stop functioning all together. The most
notable disease of myelin is MS, multiple sclerosis. A quarter of a million Americans are afflicted with
this disease. This is caused by a loss of myelin sheath which coats the nerves. When this occurs it has
the same effect as shorting out your toaster; the wires become crossed. Since nerves are really
electrical/chemical transmitters, if the cover on adjacent nerves are removed, the signals leak to the
neighboring nerves creating a confusing signal which the muscles can not understand.
Prostaglandins are a group of fatty acid like compounds discovered in the 1930s when it was found that
seminal fluid caused a uterus, that had undergone a hysterectomy, to contract. Their name comes from
the mistake of the scientist who isolated the compounds; Ulf von Euler, had thought they were produced
in the prostate gland. The prostoglandins are derived from the oxidation of arachidonic acid.
COOH
arachidonic acid
Prostoglandins are exceptionally powerful biological molecules and they control a wide variety of
biological functions. These include:
1. The inflammation of injured tissue is instigated when the arachidonic acid is released from injured
cells and is quickly turned into prostaglandins. If the area is cooled quickly and then sustained, the
inflammation will be retarded and the injury will heal more quickly and with less pain. An analgesic
can stop the oxidation of the released arachidonic acid in to the prostaglandins. Aspirin and
ibuprofen are the most predominate analgesics on the market. Another inflammation problem that
prostaglandins are found to be responsible for, is asthma. They can cause inflammation of the
bronchial passageways causing restriction in air flow. These attacks may be brought on by any
number of stimuli including allergies, stress or over activity.
2. The discovery of prostaglandins demonstrated another use, uterine contractions. An increase in
prostoglandins in the uterus is seen just before the beginning of labor. The administration of large
doses of some prostoglandins during early pregnancy has been used for drug induced abortions.
Prostoglandins have also been related to women who suffer from extremely painful menstruation
cycles.
3. Dilation of the kidney renal blood vessels is controlled by prostaglandins. An increase in their
concentration will lead to greater electrolyte excretion.
4. Gastrointestinal protection is another function of the versatile prostaglandin. They protect the
stomach by controlling the production of stomach acid and by covering its interior with a mucus
layer. As aspirin inhibits prostaglandin development, it has been shown that excessive use of aspirin
can lead to stomach ulcers.
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5. A prostaglandin derivative compound, thromboxane, is responsible for platelet aggregation. When a
blood vessel is compromised, thromboxanes are released. causing the platelets to clot the leak. Blood
thinning medication, such as aspirin will reduce the ability of platelets to come together and can
cause excessive bleeding, especially during surgery.
6. Another prostaglandin derivative compound, leukotrienes, are mainly found in white blood cells.
They can produce long lasting muscle contractions which can cause asthmatic attacks.
Steroids:
The general structure of cholesterol consists of two six-membered rings side-by-side and sharing one
side in common, a third six-membered ring off the top corner of the right ring, and a five-membered ring
attached to the right side of that. The central core of this molecule, consisting of four fused rings, is
shared by all steroids. Examples of steroids include estrogen, progesterone, cortisone, aldosterone,
testosterone, and Vitamin D. Steroids differ in the groups that are attached to the ring’s edges. Each of
the examples listed above has the same central ring, but vary in their functional group. You should be
able to draw the four rings that make up the central structure. As depicted below each ring is labeled
and each carbon is numbered. Typically a hydroxyl group (OH)will be attached to the #3 carbon.
12
11
17
13
C
1
2
9
10
A
3
8
16
15
B
5
4
14
D
7
6
Cholesterol is not a "bad guy!" Our bodies make about 2 g of cholesterol per day, and that makes up
about 85% of blood cholesterol, while only about 15% comes from dietary sources. Cholesterol is the
precursor to our sex hormones and Vitamin D. Vitamin D is formed by the action of UV light in sunlight
on cholesterol molecules that have "risen" to near the surface of the skin. Our cell membranes contain a
lot of cholesterol, in between the phospholipids, to help keep them fluid.
HO
cholesterol
Many people have heard the claims that egg yolk contains too much cholesterol, thus should not be
eaten. An interesting study was performed at Purdue University a number of years ago to test this
theory. Men in one group each ate an egg a day, while men in another group were not allowed to eat
eggs. Each of these groups was further subdivided such that half the men got "lots" of exercise while the
other half were "couch potatoes." The results of this experiment showed no significant difference in
blood cholesterol levels between egg-eaters and non-egg-eaters while there was a very significant
difference between the men who got exercise and those who did not.
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The problem with cholesterol is the same as most problems, too much. A typical American will consume
400-500 mg of cholesterol a day. The AHA recommends a maximum of 300 mg. The number one killer
of men and women over the age of 50 is heart disease. This is brought on by elevated levels of
cholesterol which will block arteries. When the blockage occurs in the blood vessels supplying the heart
with blood, a heart attack is very likely. Also, excess cholesterol levels can exceed the saturation level in
bile, causing gallstones to form. Gallstones are almost all cholesterol with a small amount of minerals,
like calcium. Maximum cholesterol levels in the blood should be 220 mg/dl of blood plasma.
Bile is another steroid. Bile salts are synthesized in your liver from cholesterol. Bile salts assist in the
digestion of lipids and other non-soluble molecules. If a gallstone is large enough it may block the
channel used to release bile and the person will suffer from jaundice and turn yellow. One other
problem is these stones can cause extreme pain. The type of pain normally reserved for childbirth.
Hormones are another derivative of steroids. The word hormone is derived from the Greek word for
arousal. At there essence hormones are chemical messengers. As you can see below, the structure of
these molecules are very similar to that of cholesterol. Drawn below are four different sex hormones.
Testosterone and estrogen are well documented hormones which give males and females their unique
physical characteristics. They also cause the production of the gametes. Progesterone prepares the
uterus for a fertilized egg, if none arrives then progesterone begins the process of menstruation.
Norethindrone is a synthetic hormone used as a contraceptive.
testosterone - androgen
progesterone
OH
O
C O
OH
O
O
HO
OH
C CH
norethindrone
estradoil - estrogen
Steroids are essential to life. But the word steroid carries a negative connotation. The anabolic steroids
used to increase physical performance can cause terrible long term damage to the liver and actually
cause males to become infertile. Side effects during use may include: hypertension, fluid retention,
increase hair growth, sleep deprivation, acne and severe mood swings.
A few anabolic steroids used include: methandienone, oxandrolone, nanodrolone and stanozolol.
Nandrolone is shown below, note its similarity to testosterone’s structure! The two molecules vary only
by the CH3 on the #10 carbon.
OH
O
Nandrolone
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Lipoproteins are clusters of proteins and lipids all tangled up together. These act as a means of carrying
lipids, including cholesterol, around in our blood. There are two main categories of lipoproteins
distinguished by how compact/dense they are. LDL or low density lipoprotein is the “bad guy,” being
associated with deposition of “cholesterol” on the walls of someone’s arteries. HDL or high density
lipoprotein is the “good guy,” being associated with carrying “cholesterol” out of the blood system, and
is more dense/more compact than LDL.
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