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1

Definition of lipids

Soluble in organic solvents, not water

2

Definition of proteins

very long chain of amino acids

3

Types of proteins

Enzymes

Hormones (i.e. peptides)

Antibodies

Neurotransmitters

4

Types of Lipids

Fatty acids: saturated, monounsaturated, and polyunsaturated

Triglycerides (TG)

Phospholipids

Sterols (i.e. cholesterol)

5

Structure of proteins

Made of amino acids (AA)

20 needed by body - 9 essential

An HN2 & COOH group

6

Structure of lipids

FA - long carbon chains

TG - three FA's bond to glycerol

Phospholipids - TG with one FA replaced by phosphorous containing substance

Sterols - multi ring structure

7

Functions of proteins

  1. Body constituents:
    1. Blood clotting
    2. Transporters (hemoglobin, lipoproteins)
  2. Structural components: muscle, bone, cell membrane
  3. Fluid balance: osmotic pressure
  4. Acid-base balance: to maintain constant conditions in the body
  5. Regulation: biochemical functions and hormones role in body
  6. Nerve impulse transmission: 2 AA's are precursors of neurotransmitters
  7. Immunity (i.e. antibodies)
  8. Energy: 4 kcals/g

8

Functions of lipids

  • Basics:
    • Energy: 9 kcals/g
    • Cell membrane, saturation
  • Eicosanoid: lipid regulatory substance
    • Thoromboxanes & prostaglandins; blood clotting, blood presure, vasodilation
  • Essential FA:
    • Omega - 3 = decrease inflammation
    • Omega - 6 = increase inflammation
  • Cholesterol
    • Cell membrane, bile acids,  steroid hormones

9

Digestion & transport of Proteins

Stomach

(denaturation; HCL/protease)

Small intestine (mucosal cells)

(down to AA/ short peptides)

Bloodstream

Cells

10

Digestion & transport of Lipids

Stomach (lipase enzymes)

Small intestine

Bloodstream

Cells

11

Requirements of protein

Adults: 0.8g/kg/day

Female adults: 46-50 g/d

Male adults: 58-63 g/d

Children: 2.2g/kg/day

Athletes: 1.2-1.8 g/kg/day

12

Requirements for Lipids

<30% kcal from all fats

<10% saturated fat

<300 mg of dietary cholesterol

13

Sources of protein

Dairy products

Meat products & legumes

Some grains & vegetables

14

Sources of lipids

Saturated FA: animal fats & tropical oils

MUFA's: vegetable oils

PUFA's: vegetable oils (6), fish oils (3)

Sterols: animal source

15

Biological value

N retained

------------------

N absorbed

(+) good

(-) bad

16

Low protein intake

  • fatigue, reduce work capacity, prone to infection and emaciation (extreme leanness)
  • ex.
    • Marasmus
    • Kwashiorkor - edema (buildiup in fluids in abdominal cavity)

17

High protein intake

Diuresis - urine formation in the kidney; losses of calcium -> osteoporosis

18

Vegetarian eating:

  • Types: lacto (dairy products), lacto-ovo (dairy products + eggs), vegan
  • Plant proteinds tend to be: low-fat, no cholesterol, high fiber, and complex CHO
  • Proteins should be complementary - bomcine proteins to improve ratio of essential AA
  • * TAKE HOME MESSAGE = vegetarian diets can be adequate when appropriately planned

19

Cardivascular disease (CVD) facts:

2nd leading cause of death in the U.S.

Incidence decrease because better medical services, not lifestyle changes

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Pathology (disease process) of CVD

Atherosclerosis

blood circulation decreases

Ischemia

Agina

blood clot

Heart attack and or stroke

21

Atherosclerosis

thickening and narrowing of artery walls caused by plaque (invasion of cholesterol)

 

22

Ischemia

insufficient blood flow

Decrease oxygen flow

23

Agina

chest pain when heart does not get enough O2

24

Myocardial infarction

heart attack; heart is deprived of O2

25

Stroke

clot in artery

O2 does not get to the brain

26

Etiology of CVD

  • LDL increase risk of CDV; >130 mg/dl
  • Low HDL; <35mg/dl
  • Total cholesterol >180mg/dl

27

Energy balance

Energy intake (EI) = Energy expenditure (EE)

28

Basal metabolism

Energy expenditure through intoluntary activity only

29

Total Energy Expenditure (TEE)

Resting Energy Expenditure (REE) + Physical activity (PA) + Thermic effect of food (TEF)

30

REE

The day's total energy expenditure through basal metabolism only

31

PA

Energy expenditure through voluntary physical effort

32

TEF

Energy expended in digesting food

33

Obesity

Contributes significantly to heart disease; type II diabetes, hypertension, cancer, stroke, and arthritis

34

Body mass index (BMI)

used to assess obesity

weight (kg)

------------

height^2 (m)

35

Body composition

lean tissue mass + fat mass

desirable range:

men 10-20%

women 18-25 %

36

Measurements of body composition

Underwater weighting

Skinfold

Body impedance analysis

37

Underwater weighting

Density of the body by comparitn dryland weight, underwater weight, and the volume of the water displaced by the body

38

Skinfold

Measures the thickness of the fat layer under the skin (such as triceps, shoulder blade, and abdomen)

39

Body impedance Analysis

Electricity is passed through the body; body water doncuts electricity, fat mass does not

How much lean mass the person has and by subtraction how much fat mass

40

Subcutaneous fat

Under the skin

41

Visceral fat

Inside the abdominal category

42

Intramuscular fat

within muscle fibers

43

Failure paths to weight control (slows metabolism)

Fasting or meal skipping

Very low calorie diets

High protein diets

44