Transcript Human Nutrition

Human Nutrition
Chapter 10
Dr. WJ Mueller
Nutrient Requirements

Macronutrients
Carbohydrates
 Protein
 Fats or oils


Micronutrients
Vitamins
 Minerals

Carbohydrates

Sugars
Monosaccharides (know 2 examples)
 Disaccharides (know 2 examples)
 Polysaccharides

• Starches
• Glycogen
• Cellulose
Proteins

From the book know
How are proteins and amino acids
related?
 the difference between essential and
non-essential amino acids
 How many amino acids are necessary
for humans
 How many are essential

Fats

The difference between fats and oils



Fats are solid at room temperature
Oils are liquid at room temperature
A fat is a glycerol molecule with three
fatty-acid molecules attached to it
H2COH-HCOH-H2COH

Glycerol
OH
H C
You do not have to know the structure,
but do know that the three long-chain
fatty acids attach to the OH molecules
to make an oil
2
OH
OH
C
H
CH2
Fatty Acids

They are chains of carbon atoms bonded to
hydrogen and oxygen atoms
COOH-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
Many of you may know that carbon atoms
require four bonds
 Structurally a fatty acid looks like this:

H
C
H
H
C
H
Fatty Acids (cont.)
If the long-chain fatty acids do not
have any double bonds between
carbon atoms it is said to be
saturated, or it has all the hydrogen
molecules it can
 Previous slide represents a saturated
fatty acid

Fatty Acids (cont.)
If the long-chain fatty acid has one double bond
along the chain, it is said to be monounsaturated,
or lacks 2 hydrogens (remember the four bond rule
for carbon atoms)
COOH-CH2-CH2-CH2-CH2-CH2-CH=CH-CH2-CH3
Double bond
H
C
H
C
H
C
H
H
C
H
Fatty Acids (cont.)

If a fatty acid has two double bonds,
then it is said to be either
polyunsaturated or diunsaturated or
lacking four hydrogens
H
H
H
C C C C C C C
H H H H H H H
Fatty Acids (cont.)
If the long-chain fatty acid has three double bonds
along the chain, it is said to be polyunsaturated, or
lacks 6 hydrogens
COOH-CH2-CH2-CH=CH-CH2-CH=CH-CH2-CH=CH-CH2-CH3
Fatty Acids (cont.)
Oils that have no double bonds tend
to be solid at room temperature
 Oils with double bonds tend to be
liquid at room temperature

Fatty Acids (cont.)
Now when you hear the phrase on a
margin commercial that it is made of
polyunsaturated fats, you will know what
they are talking about.
 You may have heard that monounsaturated
(one double bond) fatty acids are good for
you


Oils that are high in monounsaturated fatty
acids are include:
• Olive Oil
• Canola Oil
Fatty Acids (cont.)
Another term that is making an
appearance lately is “trans-fatty acids”
 In organic chemistry one learns that
there are two configurations around a
double bond. They are cis- and trans In nature, there are no trans-fatty
acids, only cis-fatty acids

Fats (cont.)

To make the perfect butter substitute,
people figured out how to hydrogenate
unsaturated fatty acids (make it more
saturated)
This is done by putting the oil under
pressure with hydrogen and a nickel
catalyst
 What does hydrogenation do?

• It breaks double bonds and adds the missing
hydrogen atoms to the molecule
Fats (cont.)

When you hear the term “partially
hydrogenated vegetable oil” you will
now know what it means
Fatty Acids (cont.)

Cis-fatty acids are when the
hydrogens are on the same side of
the double bond
Fatty Acids (cont.)

Cis-fatty acids are when the
hydrogens are on the same side of
the double bond (see below)
H
H
H
C C C C C C C
H H H H H H H
Fatty Acids (cont.)
Trans-fatty acids are when the two
hydrogen atoms are opposite to each
other (see below)
 This is not the configuration you find
in nature

H H
H H
H
C C C C C C C
H
H H
H H
Trans-fatty acids (cont.)

The only way that trans-fatty acids are
made is by hydrogenation
Some of the double bonds are broken
and reformed in the process
 When they are reformed, they have a
50-50 chance of being in cis- or transformation


Many are saying that trans-fatty acids
are bad for you
Fat Facts
The cholesterol molecule is closely
related to fats
 Plants make no cholesterol
 Only animals make cholesterol
 Even if you never eat any cholesterol,
you may be in danger of having high
cholesterol (why?)

Fats

The current thinking (always subject
to change) is that saturated fats are
bad for you


Monounsaturated fats tend to be good
for you


Increases LDL cholesterol
Decrease LDL and increase HDL (find
out what LDL and HDL refers to)
Polyunsaturated fats neither raise or
lower cholesterol
Fats (cont.)

It is also said that animal fats are bad
for you


They are made up of saturated fatty
acids
Tropical oils are bad for you (coconut
and palm oil)

Also made of saturate fatty acids
Cholesterol Story #1
You are probably familiar with
adrenalin, a chemical produced by the
body that powers the “flight or fight”
mechanism
 If someone comes up behind you in a
dark alley, your adrenalin may shoot
up

Your response might be to run a 100
meters in four seconds flat
 Or perhaps pop the oncoming person
in the nose

Cholesterol Story #1 (cont.)
I remember one time a cow chased
my cousin and me out of the pasture
 I do not remember how I cleared the
fence, but I had no problem doing it
 ADRENALIN!

Cholesterol Story #2
When adrenalin is released and then
not used, something has to happen to
it. It breaks down into other things
 One of those other things is
cholesterol (LDL)

Cholesterol Story #3
In the early 1980’s a big report came
out stating that a big study was done
and it showed that fluorescent lights
caused heart disease
 Everyone jumped! Get rid of those
fluorescent lights, it is killing our
workers!

Cholesterol Story #3 (cont.)

That is like the scientist that did an
experiment on jumping spiders
First he measured how high the spider
could jump when commanded
 Then he pulled off one leg and
measured the height he could jump
with seven legs on the scientists
command
 He continued to pull off legs and
measured how high the spider could
jump when he commanded it to

Cholesterol Story #3 (cont.)


Finally the spider had no legs and the
spider did not jump when commanded
The conclusion:

Spiders cannot hear without legs!
Cholesterol Story #3 (cont.)
The scientists conclusion on the
spider seems ludicrous, but is was no
more so than everyone changing out
the fluorescent lights
 Did people working under fluorescent
lights have more of a problem with
heart disease—Yes
 Was it caused by the lights—No

Cholesterol Story #3 (cont.)

What was the cause?
People working in offices get stressed
 When people get stressed, they
produce adrenalin
 In an office building are they using
that adrenalin to run or punch
someone out (maybe the latter!)—No
 So it has to break down to cholesterol

Cholesterol Story #3 (cont.)
What if you are in a high-stress job?
 GET EXERCISE, even if it a brisk
walk up and down the hall
 Use up some of the built up adrenalin

Cholesterol Story #4
A lady at Utah State University when I
was there (about 100 years ago) set up a
study on cholesterol.
 She paid students to:

Take a cholesterol test every day
 Keep track of everything they ate
 Keep track of when they slept
 What they did and when
 What their moods were
 Everything about their lives

Cholesterol Story #4 (cont.)
The experiment was to find out what
raised cholesterol levels
 When she analyzed the correlation
data, she was very disappointed and
to my knowledge did not publish her
results

Cholesterol Story #4 (cont.)

What did NOT raise cholesterol in
students?
Various foods (they did not make a
difference)
 Types of fats eaten (they did not make
a difference)

Cholesterol Story #4 (cont.)

What DID raise cholesterol in
students?
Breaking up with a girl or boy friend
 Having a test the next day
 Loosing a loved one
 Winning a poker game
 Beating someone in a game of chess
 Watching a football game on TV

Cholesterol Story #4 (cont.)
I think her results were very
informative
 Stresses (good or bad) increase
cholesterol



Now you know the mechanism
What should you do about it?

Get some exercise
Fats (cont.)
So what is true?
 Science has flip flopped several times
on what is good and bad in the past
20 year that I have studied fats on
what is and is not good for you

My Take-home Lesson
We probably eat too much fat as a
society, so instead of worrying about
what fat you should and should not
eat, reduce your fat intake
 Do not stress out over it
 Get more exercise

My Take-home Lesson
(cont.)

There are those individuals who have
genetic tendencies toward high
cholesterol, and those individuals
need to be more careful
Fats
May I emphasize that this is not the
end of the story.
 It will be interesting to follow what is
good and bad today may be reversed
tomorrow
