A&P CH24 Nutrition

Isocaloric Balance

• CALORIE – Amount of energy needed to raise 1 kg OF WATER BY 1℃

• The amount of energy found in FOOD

• Food quantities are often measured in KILOCALORIES (kcal)

Food intake vs. Energy Expenditure

• (+) POSITIVE ENERGY BALANCE: (calories in > calories out)

  • leads to weight gain

• (-) NEGATIVE ENERGY BALANCE: (calories in < calories out)

  • leads to weight loss

Total caloric intake depends on many factors:

• Gender

• Age

• Body frame size

• Weight

• Percentage of body fat

• Physical activity level

Don't be confused by Calories, they’re just a measurement tool, like inches or ounces.  

• Calories are the FUEL you need to work & play. They measure the ENERGY a food or beverage provides -- from the carbohydrate, fat, protein, & alcohol it contains. 

What are Nutrients?

1. CARBOHYDRATES 

2. PROTEIN

3. FATS

4. VITAMINS

5. MINERALS

6. WATER

Macro-Nutrients - Energy-yielding nutrients

• CARBOHYDRATES – 4 g/cal

  • Grains, fruits, vegetables, & legumes

• FATS – 9 cal/g

  • Oils, butter, avocados, nuts, & fatty fish

• PROTEINS – 4 g/cal

  • Meat from animals, beans, etc.

Micronutrients - Vitamins and minerals

• Provide NO ENERGY

• Some are essential

  • Need to be added via food, vitamins, etc. 

Equation

• You have 20 grams of CHO, 15 grams of FAT and 10 grams of PRO

Approximately how many calories are you eating??

• Carbohydrates – 20 X 4 = 80

• Fats – 15 X 9 = 135

• Proteins – 10 X 4 = 40

• Total - 80 + 135 + 40 = 255
  
  

Recommended Intakes

• 45–65% CHO (carbs)

• 20–35% Fats (lipids)

  • 10-10-10-0

    • Monounsaturated fats

    • Polyunsaturated

    • Saturated fats

    • Trans fats

• Protein

  • Needs reflect age, size, metabolic rate, nitrogen balance

  • Daily intake of 0.8 g per kg body weight

  • Weight in lbs / 2.2 = weight in kg → EX. 154 / 2.2 = 70 kg

  • 70 kg x 0.8 = 56 kg

What are empty calories?

• Solid fats and added sugars add calories (energy) to the food but few or no micronutrients

• For this reason, the calories from solid fats and added sugars in a food are often called empty calories.

• SOLID FATS - fats that are solid at room temperature,

  • like butter, beef fat, and shortening. 

  • Some solid fats are found naturally in foods

    • They can also be added when foods are processed by food companies or when they are prepared.

• ADDED SUGARS - sugars and syrups that are added when foods or beverages are processed or prepared.

Carbohydrates 

• are the primary fuel source for cells - ATP

  • especially for BRAIN & MUSCLES DURING EXERCISE

• Carbs yield an average of 4 cal/g

• Readily available to cells in the form of BLOOD GLUCOSE

• Stored in LIVER and MUSCLES as glycogen

  • To be used when glucose is not adequately supplied by the diet

  • Excess glucose is converted to FAT

• Brain and Nerve Tissue prefer CHO as main fuel

Root words:

• SACCHARIDE = sugar

• Mono = one

• Di = two

• OSE = standard word ending for carb

Classification of Carbohydrates

• Carbohydrate – Mainly Glucose – Is Made by Photosynthesis

How Glucose Molecules Join to Form Polysaccharides (3)

Polysaccharide - #3 Fiber (Soluble and Insoluble)

• Human digestive enzymes cannot break bonds

  • Bacteria in large intestine

• SOLUBLE – dissolve in water and easily digested by bacteria in large intestine

  • Add thickness and viscosity

  • Gel in jelly, White gummy part of oatmeal

  • Oats, barley, legumes, citrus fruits, apples, berries, pears, brussels sprouts, carrots and potatoes

  • Lowers cholesterol and controls BS

• INSOLUBLE – indigestible - retain structure

  • Outer layers of bran, strings of celery, skin of corn kernels

  • Nuts, broccoli, asparagus, carrots, spinach

  • Helps to make you feel full → SATIETY

Why Do Nutrition Experts Recommend Fiber-Rich Foods?

• Health benefits – 25–30 grams daily

  • Reduced risk of heart disease

    • Normalizes Blood Cholesterol

  • Reduced risk of hypertension

  • Reduced risk of diabetes

    • Normalizes Blood Glucose levels

    • Delays glucose absorption

  • Reduced risk of bowel disease

  • Promotion of healthy body weight

  • Constipation, hemorrhoids, appendicitis, diverticulosis

One Way Fiber in Food May Lower Cholesterol in the Blood

Fats

• Adipose tissue offers protection, insulation, fuel storage

  • ENERGY STORAGE, INSULATION & CELL MEMBRANE STRUCTURE

• Assists in absorbing, transporting and storing fat soluble vitamins A, D, E & K

• Phospholipids essential in myelin sheaths and all cell membranes

• Cholesterol stabilizes membranes; precursor of bile salts, steroid hormones

• Prostaglandins, smooth muscle contraction, BP control, inflammation

• Major fuel of hepatocytes (liver cells) and skeletal muscle

Usefulness of Fats in Food

• People naturally like high-fat foods

  • Aromas

  • Flavors

  • Tenderness

  • Satiety

Simple Fats

• Fatty Acids – basic structural unit of triglycerides

  • Classified by how they affect CHOLESTEROL

  • Based on structure, FA are classified as:

1. MONOUNSATURATED (10)

   1. Olive, canola and peanut oils

   2. Avocados

2. POLYUNSATURATED (10) – OMEGA–3

   1. Vegetable oils - Safflower, sesame, soy, corn and sunflower

   2. Nuts and seeds, Fatty Fish

3. SATURATED (10)

   1. Meat & dairy

4. TRANS FATS (0)

   1. Baking & fried foods

Triglycerides: Fatty Acids and Glycerol

• Major form of lipid found in the body

• Triglycerides

  • THREE fatty acids

  • Glycerol backbone

• Fatty acid differences

1. CHAIN LENGTH

2. SATURATION

Fatty Acids in food influence the composition of fats in the body

• SATURATION – whether a FA chain is holding all the hydrogen atoms it can hold

• Levels of saturation

  • Saturated

  • Unsaturated – “empty spots”

    • MONOUNSATURATED

    • POLYUNSATURATED

The Structure of Proteins

• PRO, CHO and Fats all contain:

  • Carbon, hydrogen and oxygen

• PRO differs in that it contains NITROGEN

  • amino – “nitrogen containing”

  • Amino Acids (AA)

• CHO – glucose molecules are identical

• PRO – strand of AA that make up PRO may contain up to 20 different kinds of AA.

Essential and Non-Essential

• 20 different kinds of AA

• Essential AA

  • Can not be synthesized by the body

  • Must get them from our diet

  • 9

• Non-Essential AA

  • Our body makes 11

Complimentary PRO

• Complementation: 2 or more incomplete PRO which together complement each other supplying the essential AA needed.

• LEGUME – Bean, Pea Lentils

  • Contain special bacteria that traps nitrogen

  • Richer in PRO than other plant foods

Variety of Proteins

• Irreversible change in a PRO folded shape brought about by heat, acids, bases, alcohol, salts of heavy metals or other agents

Protein Digestion

• Irreversible change in a PRO folded shape brought about by heat, acids, bases, alcohol, salts of heavy metals or other agents

• Ingesting large doses of a single AA may limit absorption of others that are similar

  • Too much protein and it gets turned to fat

• Allergens – Food allergies

  • Gluten (protein found in wheat)

Three factors help determine whether amino acids are used to synthesize proteins or burned as fuel:

1. All-or-none rule

   1. All amino acids needed must be present for protein synthesis to occur; if not all are present, then amino acids are used for energy

2. Adequacy of caloric intake

   1. Protein is used as fuel if insufficient carbohydrate or fat is available

3. Hormonal controls

   1. Anabolic hormones (GH, sex hormones) accelerate protein synthesis and growth

   2. Adrenal glucocorticoids (released during stress) promote protein breakdown and conversion of amino acids to glucose

Nitrogen Balance

• Nitrogen excreted as compared to nitrogen eaten

• POSITIVE BALANCE

  • More N COMING IN than GOING OUT

  • Growing kids, pregnant women or those recovering from deficiency or illness

• NEGATIVE BALANCE

  • More N GOING OUT than COMING IN

  • Body breaks down more than is consumed

• Starving, injured or sick

Vitamins

• 13

• Organic compounds that are crucial in helping body use nutrients

• Most function as COENZYMES

• Most must be ingested, except:

  • Vitamin D (made in skin)

  • Some B and K synthesized by intestinal bacteria

  • Beta-carotene (e.g., from carrots) converted in body to vitamin A

• No one food group contains all vitamins

• Two types of vitamins based on solubility

  • WATER SOLUBLE VITAMINS

    • B complex and C are absorbed with WATER

    • B12 absorption requires intrinsic factor

    • Not stored in the body

    • Any not used within 1 hour are excreted

Fat-soluble vitamins

• A, D, E, & K are absorbed with lipid digestion products

• Stored in body, except for vitamin K

  • Excessive consumption can cause health problems

• Dangerous FREE RADICALS are generated during normal metabolism

  • Vitamins C, E, and A and mineral selenium are antioxidants that neutralize these free radicals

    • Broccoli, cauliflower, brussels sprouts are all good sources of vitamins A and C

• Megadoses of vitamins are useless and may actually cause serious health problems, depending on vitamin involved

Minerals

• 7 MINERALS are required in moderate amounts:

  • Calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium

• Others are required in TRACE amounts

• Work with nutrients to ensure proper body functioning

• Uptake and excretion are balanced to prevent toxic overload

• Examples of uses in body:

  • Calcium, phosphorus, and magnesium salts harden bone

  • Iron is essential for oxygen binding to hemoglobin

  • Iodine is necessary for thyroid hormone synthesis

  • Sodium and chloride are major electrolytes in blood

• Mineral-rich foods

  • Vegetables, LEGUMES, milk, some meats