Download 14.4 Nutrition - Westgate Mennonite Collegiate

Carbohydrates
 Used as energy source in the body
 Some can be stored as glycogen (a storage
polymer) in the liver and muscles and
quickly converted back to glucose
 Excess is converted by the body to be
stored as fat
Carbohydrates
• Glycemic index: a measure of how quickly a
carbohydrate is digested and glucose is
absorbed from the small intestine to the
bloodstream. The higher the GI, the quicker
the release of glucose.
Carbohydrates
 Carbohydrates with a low GI (55 or less)
don't make our blood glucose levels rise
very high for very long. They provide
sustained energy.
 Carbohydrates with a high GI (70 or more)
are the ones that cause our blood glucose
levels to go higher for longer. High blood
glucose may cause damage to vital organs.
Carbohydrates
 Simple carbohydrates:
○ Quick to break down – sugar released quickly
○ High glycemic index
○ E.g. potatoes, white flour
 Complex carbohydrates:
○ Slower to break down – sugar is released
slowly
○ Lower glycemic index
○ E.g. whole grains, oats, beans
Proteins
 Used to build enzymes, muscle tissue,
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plasma proteins, hormones
Excess cannot be stored and is converted to
fat with nitrogenous waste begin disposed of
in urine
Eight essential amino acids (body cannot
make, must be consumed in diet)
20 amino acids total
High protein foods include: meat, beans,
dairy, eggs, nuts
Lipids
 Used as high energy source
 Include fats, oils, and cholesterol
 Serve as high energy source: each gram of
a lipid contains 2.5 times more calories than
a gram of protein or carbohydrate
 Essential fatty acids
○ Fatty acids the body can’t make must be in
diet
Lipids
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Two general categories of fatty acids:
 Unsaturated fatty acids
○ Liquid at room temp.
○ Oils, plant fats (generally)
 Saturated fatty acids
○ Solid at room temp.
○ Butter, animal fats (generally)
Lipids
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Types and Functions of Lipids
 Triglycerides
○ crucial in the body for energy storage
 Steroids
○ benefit the body by helping determine and
control the structure of plasma membrane
Lipids
 Phospholipids
○ key role in constituting cell membranes.
 Glycolipids
○ play an important role in boosting the body’s
immune system
 Lipoproteins (cholesterols)
○ help fat move around the body in the
bloodstream
○ exist in the form of Low Density Lipoprotein
(HDL) and High Density Lipoprotein (LDL)
Vitamins
 Are organic compounds (other than carbs,
lipids or proteins) that the body needs for
metabolic processes, but is unable to
produce in adequate quantities on its own
 Some vitamins are fat soluble, such as
Vitamins A, D, E, and K
Vitamins
 Others are water soluble, such as Vitamin C
○ need to take these with food b/c body can’t
absorb them otherwise and they may make
you feel ill.
 Too little or too much of a vitamin can have
harmful effects.
○ E.g. too little Vitamin D causes Rickets, bone
decalcification and weakening (osteoporosis),
but too much can cause calcification of soft
tissues, diarrhea, possible renal (kidney)
damage
Dietary Supplements

Dietary Supplements
 Are nutrients and plant products used to
enhance health
 Ironic fact: most people who take
supplements don’t need them. Why might
that be?
Minerals
 Are non-organic compounds that the body
needs to function properly.
 Examples: calcium, potassium, sodium
Minerals
○ Calcium
 Function: strong bones, teeth, nerve
conduction, muscle contraction
 Food sources: dairy, leafy green
vegetables
 Too little: stunted growth in children,
low bone density in adults
 Too much: kidney stones, interferes
with iron and zinc absorption
Minerals
○ Potassium
 Function:
 Food sources:
 Too little:
 Too much:
○ Sodium
 Function:
 Food sources:
 Too little:
 Too much:
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Complete
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