Human Nutrition

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Nutrition, Metabolism,
Body Temp Regulation
Ch 25a
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• Healthy Diets Require
• Water
• Carbs, Proteins, Lipids, Amino Acids
• Vitamins
• - water-soluble (thiamine, riboflavin, folic
  acid)
• - fat-soluble (Vitamin A, D, E, K)
• Minerals (Fe, Ca, P, Na, K)

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The Food Pyramid
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The Food Pyramid
Grains vegs fruit oil milk meat beans
www.mypyramid.gov
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Nutrient Pool
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Nutrients in the Human Diet

• Macronutrients
• Water
• Amino Acids and Proteins
• Lipids
• Carbohydrates
• Micronutrients
• Vitamins
• Minerals

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Water

• Solvent in which the chemistry of life occurs
• cell chemistry occurs in an aqueous medium
• water carries essential nutrients to cells
• water carries metabolic wastes away from cells
• hydrolysis dehydration reaction
• stabilizes body temp

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Carbohydrates

• Energy Metabolism
• catabolism of glucose during cellular respiration
  yields ATP for energy-requiring activities
• glucose stored as glycogen in the liver and
  muscle cell fibers

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Glucose Metabolism
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Carbohydrates

• Building Blocks for Other Biological Molecules
• monosaccharides join together to form
  polysaccharides that perform various functions
• monosaccharides can be coverted into building
  blocks of other kinds of biological molecules
  (e.g., lipids, proteins, nucleotides)

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Carbohydrates

• Dietary Fiber
• water-insoluble fiber adds bulk to fecal matter
  facilitating its passage through and elimination
  from the digestive system
• water-soluble fiber may absorb dietary
  cholesterol, reducing its absorption by the
  digestion tract

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Wheat Seed
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Lipids

• Triglycerides (Fats)
• energy storage molecules
• protect and cushion delicate body organs
• source of the raw materials for the construction
  of phospholipids
• unsaturated versus saturated fats

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Lipids

• Steroids (e.g., cholesterol)
• precursor molecules for steroid hormones, vitamin
  D, bile salts
• fundamental component of plasma membranes
  (influence membrane fluidity)
• HDL-cholesterol versus LDL-cholesterol

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Pathways of Lipid Metabolism
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Atherosclerosis Arteriosclerosis
normal
diseased
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Your Cholesterol Level

• Cholesterol
• Triglycerides blood fats, 30-175 mg/dl
• HDL Good cholesterol, 35 mg/dl
• LDL Bad Cholesterol,
• Chol/HDL ratio 5 indicates heart disease

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Lowering Your Cholesterol Level

• Eat healthy
• Exercise
• Lose wt.
• Quit smoking
• 1 glass of wine or beer
• Medications (Lipitor)

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Proteins

• Enzymes
• Structural proteins (shape and form of cells and
  tissues)
• Hormones
• Immunoglobulins (antibodies)

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Essential Amino Acids

• Tryptophan
• Methionine
• Valine
• Threonine

• Phenylalanine
• Leucine
• Isoleucine
• Lysine
• Arginine

• Histidine
• (infants)

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Complete ProteinsVersusIncomplete Proteins
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• Vegetarian diet may result in protein deficiency
• Need essential amino acids
• beans ? lysine isoleucine
• corn ? tryptophan methionine

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Transamination
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Vitamins

• Organic compounds needed by the body in small,
  but essential amounts
• Cannot be synthesized by the body in sufficient
  amounts
• Function in a variety of ways in metabolic
  reactions
• Thirteen known vitamins

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Water-Soluble VitaminsVersusWater-Insoluble
Vitamins
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Water-Soluble Vitamins
C (ascorbic acid) B1 (thiamin) B2
(riboflavin) Niacin B6 (pyridoxine)
Pantothenic acid Biotin B12 (cyanocobalamin) Folic
acid
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Water-Insoluble Vitamins

• A (retinol)
• D
• E
• K

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Minerals

• Essential inorganic elements
• Involved in a variety of metabolic processes
• Major minerals versus trace minerals

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Major Minerals

• Calcium
• Phosphorus
• Magnesium
• Sodium
• Potassium
• Chlorine

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Trace Minerals

• Iron
• Iodine
• Fluoride
• Zinc
• Copper

Manganese Cobalt Selenium Chromium
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• An animal whose diet is missing one or more
  essential nutrients is said to be malnourished.

Giraffe eats bone to get phosphorus nutrient
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• Obesity may be gene related
• Leptin
• ? leptin levels ? appetite
• loss of body fat ? leptin levels and ? appetite
  and wt gain
• potential medications for obesity

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Homeostasis

• All organisms must maintain a constant internal
  environment to function properly
• Temperature
• pH
• ion levels
• Hormones

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Homeostasis via Negative Feedback
Blood Sugar Levels
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Heat and Energy Balance
Heat- calories or kilocalories Metabolic Rate-
measure in BMR
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Body Temperature Homeostasis

• Heat Production
• Exercise
• Hormones
• Nervous system
• Body temperature
• Ingestion of food
• Age
• Other factors

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Body Temp Regulation
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Four physical processes account for heat gain or
loss

• Heat exchange by
• Conduction- transfer of heat between objects in
  direct contact with each other
• Convection- heat is conducted away from an object
  of high temp to low temp
• - Rate varies with different materials
• Radiation- transfers heat between objects not in
  direct contact
• - sun energy
• Evaporation- change of liquid to vapor
• - cooling

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Heat exchange between an organism and its
environment
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INQUIRY

• What are nutrients that the body needs but cant
  synthesize on its own called?
• Which cells of the body, under normal
  circumstances, must have energy in the form of
  glucose in order to survive?
• How does the body make use of dietary
  cholesterol?
• What is an incomplete protein?
• What trace element is necessary for wound
  healing?
• Neural tube defects are easily prevented by the
  adequate intake of ____ by pregnant mothers.
• What carbohydrate can be found in a steak?
• Hemorrhaging could occur because of lack of
  sufficient vitamin _____.

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Moment of Zen