Transcript Nutrition Lecture 2012

Nutrition
www.mypyramid.gov
What is a nutrient?
A chemical that the body requires
from the environment.
The Six Nutrients…what are
they?
• Carbohydrates
• Fats
• Proteins
• Vitamins
• Minerals
• Water
Carbohydrates
• Sources: starches, sugars,
cellulose, glycogen
• Fiber: cellulose; provides
bulk movement
• Use: cell energy (neurons!),
stored energy, nucleotide
sugars, lactation
• RDA: 45-65% of diet
Fats
• Sources: triglycerides (saturated(solids),
unsaturated(oils), trans fats), phospholipids,
and cholesterol.
• Use: energy, energy storage, protection,
structural material, hormones
• Requirements: Essential FA – linoleic,
linolenic, arachidonic. (Fish oils are good
source and flax seed.)
• RDA: 20-35% of diet
Trans Fat!
• All hydrogenated
oils
• Increases cholesterol
levels
• Lowers absorption of
some essential
vitamins
• Increases visceral fat
• Directly linked to
heart disease,
diabetes, etc.
Ingredients: ENRICHED FLOUR [WHEAT
FLOUR, NIACIN, REDUCED IRON, THIAMINE
MONONITRATE (VITAMIN B1), RIBOFLAVIN
(VITAMIN B2), FOLIC ACID], SUGAR,
PARTIALLY HYDROGENATED VEGETABLE
OIL, (SOYBEAN, COTTONSEED, PALM
AND/OR PALM KERNEL OILS, TBHQ AND
CITRIC ACID TO PRESERVE FRESHNESS)),
COCOA, CARAMEL COLOR, CONTAINS TWO
PERCENT OR LESS OF COCOA PROCESSED
WITH ALKALI, INVERT SUGAR, WHEY (MILK),
LEAVENING
Sources of Trans Fats
Cholesterol (not a nutrient)
• Fat-like substance, made in liver and ingested
• Uses: hormones, cell membranes
Cholesterol/Fatty Acid Carriers:
LDL (BAD) – deposits in tissues or vessels
HDL (GOOD) – takes to liver to be converted
Proteins
• Sources: meats, dairy,
legumes, fish, poultry,
eggs, cereals, nuts,
vegetables
• Use: growth, repair,
enzymes, hormones,
collagen etc.
• 20 amino acids you use
in your body. 8 are
essential.
• RDA: 10-35% of diet
Vitamins
• Organic compounds
• Required in small amounts for metabolic
processes, blood clotting, vision, collagen
synthesis, bone development…
Two Groups:
• Water soluble: Vitamins B’s and C, folic
acid, niacin and many others…
• Fat soluble: Vitamins A, D, E and K
Minerals
• They are ELEMENTS not compounds!
• Essential for metabolism and major cell
processes (nerve impulses, muscle contraction,
thyroid function…)
• 4% of body weight (most in bones/teeth)
• Major Minerals: Ca, P, K, Na, S, Cl, Mg
• Trace Elements: Fe, Mn, Cu, I, Zn…
Metabolism: Your
Engine!
What is my metabolism?
• The rate or speed at which you burn
calories (use energy for cell processes).
Calories are the energy stored in foods that is converted
into ATP for our body to use.
Basal Metabolic Rate (BMR)
• Minimum amount of calories required to
sustain life. 70% of total caloric
expenditure.
Total Daily Energy Expenditure
• Amount of calories burned per day. This
includes exercise and daily life activities.
Energy Input = Energy Output
To maintain weight at present
number.
How does one lose weight?
Eat less energy then you use daily
How does one gain weight?
Eat more energy then you use daily
Nutrient Calories
• Carbohydrates = 4 Cal/gram
Proteins = 4 Cal/gram
• Fat = 9 Cal/gram
• Vitamins = 0 calories
• Minerals = 0 calories
• Water = 0 calories
Know how to
read a food
label!
What do all the
%’s mean?
Problem: A bag of pretzels contains 200
calories per serving. It contains 40 grams
of carbohydrates per serving.
You ate 5 of the 20 servings from the
bag…OINK!
• How many total calories did you eat?
1000 Calories!
(That’s approx. half your of your daily calorie needs!)
•
How many of the calories come from
carbohydrates? (Hint: carbs = 4 Cal/gm)
4 Cal/gm x 40gm = 160 Cal of carbs per serving.
But, you ate 5 so… total carb calories = 800!
(80% of the pretzel calories come from carbs.)
Problem: A bag of peanuts have 500
Calories per serving and 15 grams of protein
per serving.
How many of the total calories are coming from protein?
15 x 4 cal/gm = 60 calories
What % of the total calories per serving is coming from
protein?
60/500 = .12 x 100 = 12%
If this was all the diet consisted of, would it meet the RDA
for protein?
RDA = 10-35%...YES!
(but, not all essential nutrients are met…malnutrition will occur.)
What % of your calories is
coming from fats?
1. Calculate your average daily intake.
ex: 2500 calories eaten daily
2. Calculate your average gram intake of fats.
ex: 85 grams of fat on average daily
3. Calculate the number of calories from the
average fat grams.
ex: 85 grams x 9 cal/gram = 765 calories
4. Find the percentage of fat in diet:
ex: 765 fat calories/2500 total calories x 100 = 31%
5. Does this % meet or exceed the RDA for fat?
Mass Measurements…
How can body composition be measured?
How body fat is measured
• Bioelectrical impedance
• Hydrostatic weighing
• Skin-fold measurements
Body Mass Index
• Calculated from one’s
weight and height.
• Relative indicator of one’s
quantity of body fat.
• False obesity readings can
be seen in very muscular
people. Muscle mass % is
not distinguished from fat
%.
Waist to Height Ratio
• “WHtR” is calculated by
dividing waist size by
height
• Better health accuracy
since fat in the abdomen
is measured, which is
associated with harmful
diseases.
• Athletes score better
here because their
waists are typically in
normal range.