Amino group needs to be excreted

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Outline for today

• Continuing our overview of nutrition
• Nutrient types (lipids, proteins, vitamins,
  minerals)
• Hunger/satiety
• Guidelines for healthy diets
• Nutrient density
• Food pyramid/dietary guidelines/RDAs etc
• Choices of issues/topics
• CPS system
• Diet analysis

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Nutrition in the News
I would like you to bring in any interesting
nutritional news you come across (e. g.
newspaper clippings, ads in magazines). We'll
discuss these in class - point out the strengths
and weaknesses, and try to determine if any
claims made are likely to be valid.
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Food Wise software Directions on the web page,
but it is very easy to use. To save a file use
p to print and then print to file, not printer.
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BMI Body Mass Index

• BMI body weight in kg/(height)2 in meters
• weight in pounds x 703.1/(height)2 in
  inches
• If your height is 60 inches and your weight is
  128 lb your BMI is 25
• 63 141
• 65 150
• 68 164
• 70 174
• 73 189
• Roughly, 6-7 lbs 1 BMI unit
• BMI of 25-30 overweight
• BMI 30 obese

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Issues - Topics Your thoughts? Diets, obesity,
eating disorders Low carbohydrate diets Food
Safety Vegetarian diets Supplements vitamin,
herbal, other Sugars, glycemic index
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Nutrition
- a very complex science - large number of
factors and variables involved, very intricate
feedback control and regulatory systems (e.g. the
levels of sugar and other metabolites in your
blood remain relatively constant). - many
pressing questions relating nutrition and health
are not yet fully answered, - very complex
nature. - In the context of human nutrition it
is difficult to conduct many of the desired
experiments for ethical reasons, and long
lifespan. E. g. if a dietary component can
trigger cancer in susceptible individuals it may
take 15 or more years for this to happen. It is
becoming apparent that animal models may not be
such good models for humans.
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• A 20-year study in California of 7,000 people
  showed the following lifestyle elements
  correlated with optimal quality of life and
  longevity
• Avoiding excess alcohol
• Not smoking
• Maintaining desirable weight
• Exercising regularly
• 7-8 hours sleep/night
• Not snacking between meals
• Eating breakfast

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Last time we finished up with a discussion of the
nutrients, and started on carbohydrates
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What is a Calorie?

• A (nutritional) measurement of energy
• the amount of heat it takes to raise the
  temperature of 1 gram of water by 1 degree
  Celsius
• A nutritional Cal is actually 1 kcal
• Distinguish between calorie and Calorie

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Lipids
The other major energy source (higher energy
content/weight than carbohydrate). Supplies
essential fatty acids, necessary for adsorption
of fat soluble vitamins, vital components of
membranes.

• Composed of C, H and fewer O
• Basic unit is fatty acid
• Triglyceride is the major form of lipid
• Fats and oils
• Unsaturated Fatty Acids
• Saturated Fatty Acids
• Trans fatty acids
• Essential Fatty Acids
• Energy yielding (9 kcal /gm)

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Proteins
source of amino acids for growth new proteins
(for tissues, antibodies, enzymes, hormones
etc.), can provide energy, are important
structural and functional components of bodies

• Composed of C, O, H, N
• Basic unit is amino acid (string of beads)
• Make up bones, muscles, other tissues, and
  components
• (9) Essential amino acid
• (11) Nonessential amino acid
• Energy yielding (4 kcal /gm)

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Space-filling model of the protein hemoglobin
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Fig. 1.1c
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Vitamins

• Composed of various elements
• Essential for life
• Enable chemical reactions
• Needed in tiny amounts
• Fat soluble or Water soluble
• Yield no energy

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Minerals

• Inorganic substances
• Function in cellular process, nervous system,
  water balance, bones
• Needed in tiny amounts
• Not destroyed in cooking
• Trace minerals/Major minerals
• Yield no energy

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Water

• Vital to life
• Requirement about 8 cups/day
• Is a solvent, lubricant, medium for transport,
  chemical processes, and temperature regulator
• Makes up majority of our body (60)
• not necessarily as glasses of water can be
  any food/drink containing water
• (varies with size, activity, temperature)

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What Is A Healthy Diet?

• One with
• Variety
• Balance
• Moderation

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The American Diet

• In general the US diet has
• Too much fat, salt, alcohol and simple sugars
• Potentially insufficient
• iron, calcium, zinc
• Vitamin A, C, some of the B vitamins
• Fiber

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Why variety, moderation and Balance?
Variety ensures that you will get all the
necessary nutrients. Most individual foods are
incomplete as far as our needs are concerned. In
addition, there are many compounds in foods that
are beneficial for our health (phytochemicals) Ba
lance means consuming foods from the five major
food groups - this is the basis of the "food
pyramid" idea. Together, these different classes
of foods will provide all the necessary nutrients
you need. Moderation - not good to have
excessive amounts of any one food in your diet.
One reason is that for several essential
nutrients, too much is not good for you, e. g.
Vitamin A or iron. In general, the nutrients that
have the smallest difference in concentration
between optimal and toxic effects are Vitamins A
and D, iron, copper, calcium, and in fact, most
minerals (if you take supplements check these
out).
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The general consensus among nutrition experts is
that your diet should provide 55-65 of Cals
from carbohydrates, 10-15 from protein and
from fat.
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Desire to eat

• Hunger
• Physical biological drive
• Appetite
• Psychological drive
• Controlled by many hormones, blood sugar level
  etc.

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Satiety

• Regulated by the hypothalamus
• Meal size and composition
• Hormones

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Influences of Food Choices
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All Foods Are Not Created Equal

• Nutrient density
• Comparison of vitamin and mineral content to
  number of kcals
• Empty calories
• Provides kcals and few to no other nutrients
• Energy density
• Comparison of the kcal content to the weight of
  the food
• Low-energy-density foods in a meal contributes to
  satiety
• Foods with more water and dietary fiber

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Comparison of Nutrient Density
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Table 2.3
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Desirable State of Nutritional Health

• Intake meets bodys needs
• Body has a small surplus

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The Food Guide Pyramid

• To translate science into practical terms
• To help people meet the nutritional needs for
  carbohydrate, protein, fat, vitamins, minerals
• Provides a foundation to eating

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The Food Guide Pyramid
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Other Pyramids

• Mayo Clinics Healthy Weight Pyramid
• DASH Pyramid
• Ethnic Pyramids
• Dr. Walter Willetts Healthy Eating Pyramid
• The America Institute for Cancer Researchs Plate
  (vs. Pyramid)
• All with an emphasis on fruits, vegetables, and
  whole grains

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Using the Pyramid

• Choose low-fat options
• Include plant proteins several times a week
• Include dark green vegetable every day
• Include a vitamin C rich food every day
• Choose whole-grain products
• Include plant oils daily

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Table 2.8a
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Table 2.8b
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Table 2.10