Chapter 13 - Nutrition Flashcards
Estimated Average Requirement (EAR)
Average daily nutrient intake level estimated to meet the requirement of 1/2 the healthy individuals who are in a certain life stage and gender group
Recommended Dietary Allowance (RDA)
Average daily nutrient intake needed to meet the the nutrient requirements of nearly all (97-98%) healthy individuals who are in a particular life stage & gender group
Adequate Intake (AI)
A recommended average daily nutrient intake level, based on observed (or experimentally determined) estimates of nutrient intake. This intake is assumed to be adequate for a group(s) of healthy people. This measure is used when RDA can’t be determined
Tolerable Upper Intake Level (UL)
Highest average daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in a particular life stage and gender group. As intake increases above UL the potential risk of adverse health effects increases.
Purpose of Dietary Guidelines
- to encourage most Americans to eat less calories, be more active, and make healthier food choices
- these are general guidelines and don’t provide info on specific requirements for each nutrient. Dietary Reference intake values provide that info.
- info on food labels can assist people in meal planning and making better food choices
Dietary Reference Intake
Dietary standards used to plan/evaluate diets
Macronutrients
Nutrients that provide the body’s energy & mass
-include carbs, fats, & proteins
see charts on pages 242-243 for macro intake recommendations
Kilocalorie (kcals)
unit of energy = 1000 calories
Carbohydrates
made up of carbon & water; are charactarized as simple or complex based on the carbon-water units they contain
4 calories/gram
- complex: more than 10 carbon-water units
-simple: disaccharides: table sugar, milk, sweet potatoes
monosaccharides: glucose, fructose, galactose
- contain fiber & starch found in whole grains and veggies
- body stores small amounts of carbs in the liver & skeletal muscles as glycogen
- liver glycogen helps maintain blood glucose (supplies energy to the body — fuels brain, other body cells that can’t use fat as fuel
-they fuel body before, during, & after exercise
see chart on page 243 fro complete list of carbohydrate sources
blood glucose
sugar transported to the body to supply energy to the body’s cells ( brain, others that can’t use body fat as fuel)
Recommended Carb Intake
45-65%of total calories from carbs (primarily complex carbs)
- those who exercise may need more carbs than those who are sedentary
- complex carbs can be found in milk, & nearly all plant foods
Nutrient Density
Nutrient content of a food relative to it’s calorie content
see page 244 for nutrient density chart
Fats (aka lipids)
group of compounds that include triglycerides (fats & oils), phospholipids and sterols
- 9 calories/gram
- insoluble in water
- fats are stored in the body mostly as triglycerides
- provide over 2x as much energy as carbs; one lb of fat = 3500 calories
- carbon chains linked together
- classified based on saturation (extent to which all carbons-hydrogen bonds are filled)
Saturated Fat
Chains of carbons bonded to all of the hydrogen atoms it can hold
Monounsaturated Fatty Acid
a carbon chain with just one missing hydrogen atom
Polyunsaturated Fatty Acid
a carbon chain with several spots where hydrogen atoms are missing
- Omega 3 fatty acids have anti-inflammatory effects & help decrease blood clotting
- Omega 6 fatty acids promote blood clotting & cell membrane function
Triglyceride
Chemical or substrate form in which most fat exists as well as in the body
Functions of Fat
- energy storage
- provides essential fatty acids
- absorbs/transports fat-soluble vitamins
- protects/insulates vital organs
- helps cell membrane structure
- precursor or steroid hormones
Low-density Lipoprotein
Molecule that carries lipids throughout body; delivers cholesterol that can build up on artery walls
Recommended Intake of Fat
- 20-35% of total daily calories
- fewer than 10% of total calories should be from saturated fats (use polyunsaturated and monounsaturated whenever possible)
Food sources of fats
- meat, cheese butter, egg yolks & creamy sauces = saturated fats
- vegetable oils like soybean, corn, & sunflower oil; fish, flaxseed & walnuts = polyunsaturated fats
- olive, canola, peanut, safflower, & sesame oils, nuts, & avocados = monounsaturated fats
see table on page 246 for more food sources of fats
Proteins
- long chains of amino acids with nitrogen attached to them
- contain carbon, hydrogen, & oxygen too
- 4 calories/gram
see page 246 for complete list of amino acids
Essential Amino Acids
Amino acids that can’t be produced by the body and must be obtained from eating food
-Lysine, Valine, & Histidine are some examples
Nonessential Amino Acids
Amino acids produced by the body; don’t need to be obtained from food
- Glycine, Proline & Serine are some examples
Complete Protein (aka high quality protein)
provides all essential amino acids & can easily be digested & absorbed
- usually from animal sources; meat, eggs, & dairy products
see table on page 248 for list of complete/complimentary proteins
Incomplete Protein
food that doesn’t contain all essential amino acids in the amount needed by the body
- includes beans, legumes, grains, & veggies
Complimentary Proteins
Two or more incomplete proteins that can be combined together to provide all essential amino acids
-examples: rice & beans, hummus & a whole grain pita
Function of Water
- transports nutrients
- rids the body of waste
- stabilizes body temp
- releases heat through evaporation
- lubricates joints
- maintains the body’s acid-base ratio
Recommended Water Intake
- women: 2.7 L (91 oz) per day
- men: 3.7 L (125 oz) per day
- 2 hours pre-exercise: 14-20 oz
- 15 mins pre-exercise: 16 oz if tolerated
- during exercise: 4-8 oz every 15-20 mins or 16-32 oz every hour; depends on rate of sweat
- post exercise: 16 oz per pound of body weight lost
Electrolytes
- minerals such as potassium, sodium, calcium, chloride, magnesium & phosphate; all are needed to control fluid balance between various body systems.
- sodium, potassium are the most important ones that get depleted by sweat; must be replaced when significant amounts are lost
- severe depletion unlikely in physical activities under 2 hours.
Water Balance
Staying hydrated depends on the balance between water loss and intake. Water loss is effected by factors like temperature, humidity, age, intensity/duration of exercise, fitness level
see chart on page 250 on water balance from intake & output
Dehydration
- a loss of 2-3% body weight as water can decrease exercise capacity & increase risk of death
- dehydration is often compounded with severe loss of electrolytes, which may cause heat stroke
- some symptoms include dry mouth, thirst, fever, dizziness, fever.
See chart page 251 for more symptoms
-dark urine often indicates dehydration
see table 13.11 for ways to avoid dehydration
Eating Before Exercise
- has been shown to improve performance (as opposed to not eating before exercise) during workouts
- eat a balanced meal 3-4 hours before activity
- meal should be high in carbs, low in both fat, includes whole grains and starches, include complete protein
- meal replacement shakes can be an option
Eating during exercise
- not necessary for most activities lasting less than an hour
- early morning workouts may require eating since glycogen stores can be low from overnight fast
- workouts lasting longer than an hour may require 30-60 grams of carbs per hour (boosts performance for endurance activities
Eating Post - exercise
- consume a meal with a carb to protein ration of 4:1; about 35-40 mins after exercise
- allows insulin receptive muscles to repair
