Exam 1

sports nutrition

a specialization within the nutrition field that requires the knowledge of both nutrition & exercise science

• goes beyond general health & wellness

• involves:

  • energy for physical activity and/or competition

  • nutrients for repair, recovery, & adaptation to physical training

  • designing practical dietary strategies to achieve above goals

registered dietitian (RD) / registered dietitian nutritionist (RDN)

healthcare professional trained to provide food & nutrition information to the public

• has a college degree

• has academic & clinical experience in nutrition

• credential = RD

nutritionist

• college degree NOT necessary

• may not have any formal background in nutrition

• no formally recognized nutritional credential

licensure

• necessary for RDs in 48 states & Puerto Rico

• regulates use of professional titles, who can practice, & scope of practice

• process was initiated in states to ensure that only qualified professionals, with proof of adequate education & experience, provide nutrition services or advice to individuals seeking nutrition care

non-RD & nutrition advice

• permitted to give nutrition advice if:

  • “public domain” information

  • not specific “nutritional counseling”

  • not medical nutrition therapy

non-RD referrals to trained RDs or medical staff

• eating disorders or other medical conditions like diabetes, hypertension, etc.

• interpretation of medical labs or other information

• nutrition assessments & care plans

• whenever nutritional issues are beyond expertise

essential

a nutrition descriptor referring to nutrients that must be obtained from the diet

• includes carbohydrates, fats, proteins, minerals, vitamins, & water

macronutrients

needed in large amounts to provide energy & support basic daily functions

• provide calories

• includes carbohydrates, proteins, & fats

carbohydrates

composed of sugars (glucose) that provide the body with energy

• 4 kcals/gram

• sugars are a compoind made of carbon, hydrogen, & oxygen

• found in many foods including grains, fruits, vegetables, etc.

• formed by plants via photosynthesis

• stored in plants as starch

proteins

composed of amino acids (essential & nonessential) & are involved in the growth & repair of body tissues

• amino acids can be obtained from within the body or from dietary sources

• composed of carbon, hydrogen, oxygen, & nitrogen

• also provide some energy

• found in many foods including dairy, animal meats, etc.

nonessential

a nutrient descriptor referring to nutrients that can be made within the body

fats

also known as lipids & serve as a concentrated form of energy

• 9 kcals/gram

• provide structure to body tissues (nerves & cell membranes)

• are concentrated in foods like butter, oils, & meats

micronutrients

essential vitamins & minerals that the body needs in small amounts to support normal growth, development, & overall health

• do not provide calories

vitamins

are essential to at least one vital process & must be obtained from diet

• composed of carbon & other elements

• are found in nearly all foods including fruits & vegetables

vitamin classifications

• water soluble

• fat soluble

water soluble

a vitamin classification

• dissolve in water, travel freely through the blood stream, & are not stored in large amounts by the body

• difficult to get too much of

• includes B vitamins & vitamin C

fat soluble

a vitamin classification

• a specific group of vitamins that dissolve in fats & others rather than in water

• stored

• supplements carry large amounts of these

• includes vitamin A, D, E, & K

minerals

serve as important structural, electrical, & chemical roles in the body

• composed of elements other than carbon

mineral classifications

• major

• minor

major

a mineral classification

• requirements > 100 mg/day

• includes:

  • Calcium

  • Sodium

  • Potassium

  • Chloride & others

minor

a mineral classification

• requirements < or = to 100 mg/day

• includes:

  • Iron

  • Zinc

  • Copper

  • Iodine & others

water

essential to life & maintains 55-60% of body weight

• needed in large amounts but does not provide calories

• functions:

  • temperature regulation

  • lubrication of joints

  • transport of nutrients to active tissues

producing energy

• carbohydrates, fats, & proteins are metabolized (energy nutrients)

• energy is released

• ATP is formed

• ATP is the “direct” source of energy for muscle activity & allows for muscles to generate force

recommended dietary allowances (RDA)

average daily dietary intake level of a nutrient that meets the needs of 98% of healthy people

dietary reference intakes (DRIs)

reference values used to plain & assess the nutrient intakes of health people

• expands the RDA & includes other quantities (EAR, AI, & UL)

my plate

a guide to improve the nutrition & well-being of American by helping consumers focus on key nutrition behaviors

• includes fruits, vegetables, proteins, grains, & dairy

Food & Drug Administration (FDA)

the governing body responsible for ensuring the safety of foods sold in the US

requirements for labeling

• statement of identity

• net contents

• manufacturer information

• ingredient list

• nutrition facts panel

statement of identity

commonly used name or descriptive title of the food product

net contents

indicates the quantity of food in the package expressed in weight, volume, or count & is found on the front of the label along the bottom edge

manufacturer information

located near the ingredient list & is usually in small print

ingredient list

used to evaluate nutritional quality of food & used to avoid certain additives or foods to which athlete may be allergic or intolerant

• ingredients are listed in descending order of predominance based on weight 

nutrition facts panel

includes serving size information, total calories, fat/carbohydrate/protein content, vitamin & mineral information, percent daily values (%DVs), & sugar alcohol (can cause bloating or stomach cramping)

• vitamins more than 20% are a good source & less than 5% is minimal

nutrient claims

nutrient-related claims on food labels that highlight certain food characteristics of the food

health claims

a description placed on a food label that describes potential health benefits of a food or nutrient

nutrition & health claims

are regulated by the FDA but not required

considerations when developing an athlete’s nutrition plan

• health history

• energy demands of the sport

• total weekly training & competition time

• living arrangements

• access to food

• travel schedules

nutrients after ingestion

1. digestion

2. absorption

3. transport

4. assimilation and/or energy production

digestion

breaks down food into smaller molecules that the body can use

• begins with mastication (chewing)

• also involves enzymes that chemically break down nutrients

absorption

nutrients move from digestive tract into the body

• occurs primarily in the small intestine

transport

absorbed nutrients are transported around the body

• blood transports most nutrients

• lymph must transport dietary fats first

assimilation and/or energy production

once nutrients reach cells, they can be used to build body structures, stored, converted into other substances, or used to produce energy

anatomy of the digestive system

• mouth (oral cavity)

• esophagus

• stomach

• small intestine

• large intestine

• rectum & anus

mouth (oral cavity)

includes the salivary glands (parotid, sublingual, & submandibular)

• secrete saliva to moisten food & contain enzymes that begin digestion

esophagus

carries food from mouth to stomach

stomach

muscular organ & major role is digestion

• major secretions of hydrochloric acid (HCl; creates an acidic environment), mucus (protects stomach lining), & digestive enzymes (breaks down nutrients)

small intestine

main site of digestion & absorption

• three sections:

  • duodenum —> majority of digestion occurs here

  • jejunum —> little digestion, mostly absorption

  • ileum —> mostly absorption

• surface area for absorption by villi & microvilli

• interior is convoluted & allows for more space for nutrients to be absorbed

large intestine

mostly involved with water & electrolyte absorption

• includes the ascending, transverse, & descending colon

  • some absorption of water, sodium, chloride, potassium, & vitamin K

passion diffusion

• high to low concentration

• no protein carrier needed

• no energy required

facilitated diffusion

• high to low concentration

• protein carrier needed

• no energy required

active transport

• gradient does not matter

• protein carrier needed

• energy required

endocytosis

• cell engulfs particle

• across cell membrane

• energy required

digestion of carbohydrates

1. begins with mastication & enzyme called amylase

2. hydrochloric acid in stomach allows for 1-4 hours of churning

3. sugar enzymes (maltase, sucrase, lactase) among small intestine break carbohydrates into smaller sugars that can be absorbed

4. bacteria in large intestine act on some carbohydrates that were not digested/absorbed earlier

absorption of carbohydrates

• occurs primarily in small intestine

• different sugars use different mechanisms

  • fructose —> facilitated diffusion

  • glucose —> active transport

  • galactose —> active transport

carbohydrates after absorption

small intestine —> blood —> cells

• insulin / glucose transporters help with cellular uptaje

• glucose can be used for energy, stored, or converted into other substances

digestion of fats

1. begins with mastication & enzyme called lingual lipase

2. gastric lipase in stomach allows for 2-4 hours of churning

3. bile, pancreatic lipase, & micelle formation among small intestine act to break large fat droplets into smaller droplets

absorption of proteins

• occurs in small intestine

• mechanisms of facilitated diffusion & active transport

• very little proteins make it to the large intestine

proteins after absorption

small intestine —> blood —> amino acid pool

• amino acids can be used to make body proteins, other compounds through conversion, or energy (when needed)

absorption of fats

occurs in small intestine

• mechanism of passive diffusion

• very little fat makes it to the large intestine

fats after absorption

small intestine —> lymph —> blood

• fat is packaged into chylomicrons

• lipoprotein lipase helps make fatty acids available for cells

• storage or used as energy

digestion of proteins

1. begins with mastication

2. churning & acid denaturation (unraveling) in stomach & enzyme pepsin (responsible for 10-20% of protein digestion)

3. proteases & peptidases in small intestine

transcription

converts DNA into messenger RNA (mRNA) inside the cell nucleus

translation

uses mRNA to build proteins

digestion / absorption of vitamins, minerals, & water

do NOT need to be further digested

• absorption occurs in small & large intestines

metabolism

all the chemical reactions occuring in the body

anabolic metabolism

uses energy to build larger molecules from smaller ones

catabolic metabolism

releases energy by breaking larger molecules into smaller molecules

basal metabolic rate (BMR)

minimum amount of energy to function while awake & at rest

• similar to resting metabolic rate (RMR)

• RMR is less strict

predictive equations

can be used to estimate BMR & RMR

• may use factors such as age, sex, height, body mass, etc.

activity factors

physical activity level influences energy needs

• more activity = more energy required

thermic effect of food (TEF)

energy the body uses to digest, absorb, & process food

illness or injury

can increase energy needs for healing, immune response, recovery, etc.

energy

entity that enables the body to perform work

• has no shape or physical mass

• human bodies rely on chemical energy

• includes macronutrients & adenosine triphosphate (ATP; direct energy source)

  • cells nevery fully deplete their store of ATP

  • fatigue is a protective mechanism when energy levels are low

• units —> kilocalories (kcals)

energy systems

• phosphagen

• anaerobic

• aerobic

phosphagen energy system

• immediately/fastest energy system

• uses ATP stored in the muscle & creatine phosphate (CP)

• 5-15 second capacity

anaerobic energy system

• does not require oxygen

• uses only carbohydrates

• associated with lactate production

• 1-3 minute capacity of high intensity activity

aerobic energy system

• requires oxygen

• uses all macronutrients

• slowest at producing ATP, but has a much greater capacity for producing energy over a long period

• best for low to moderate, long-duration activity

enzymes

a group of complex proteins whose function is to catalyze biochemical reactions in the body

gastrointestinal (GI) tract

the regions of the digestive system that include the stomach, small intestine, & large intestine

villi

small, rod-shaped projections that cover the walls of the small intestine

defecation

the physical process of excreting feces from the rectum

amylase

a digestive enzyme that breaks down carbohydrates into simple sugars

lingual lipase

an enzyme for fat digestion that is secreted by cells located at the base of the tongue

gastric lipase

a fat-digesting enzyme secreted by cells of the stomach

pancreatic lipase

a digestive enzyme secreted by the pancreas into the duodenum that breaks down triglycerides

micelles

tiny bubbles made up of monoglycerides and long-chain fatty acids that are wrapped in bile salts

• help transport digested fats to the intestinal wall for absorption

chylomicrons

a droplet made of resynthesized triglycerides wrapped in lipoproteins that is produced by the intestinal walls

lipoprotein lipase (LPL)

a specialized enzyme that breaks down triglycerides into glycerol & free fatty acids

proteases

a class of protein-digesting enzymes that break the chemical bonds holding amino acids together

peptidases

a group of protein-digesting enzymes that are released from cells of the small intestine

• work on breaking the chemical bonds of short-chain proteins

classifications of carbohydrates

• simple

  • monosaccharides

  • disaccharides

• complex

  • oligosaccharides

  • polysaccharides

monosaccharides

single, simple sugar units/molecules

• ex —> glucose, galactose, & fructose

glucose

provides energy & regulates blood sugar levels

• main energy source for the brain

galactose

combines with glucose to form lactose

fructose

naturally found in fruits & provides energy

• commonly paired with glucose in foods

disaccharides

composed of two, simple sugar units/molecules joined together

• ex —> sucrose, lactose, & maltose

sucrose

glucose + fructose

• commonly known as table sugar

• naturally found in fruits & some vegetables

lactose

glucose + galactose

• commonly known as milk sugar & is found in milk & dairy products

maltose

glucose + glucose

• formed during the breakdown of starch & is found in malted foods

oligosaccharides

short chains of 3-10 simple sugar units/molecules

• ex —> maltodextrin & corn syrup