Nutrition Flashcards
sports dietitian
a registered dietitian (registered dietitian nutritionist) with specific eduction and experience in sports nutrition.
the academy of nutrition and dietetics (AND) board certified specialist in sports dietetics (CSSD) certification distinguishes registered dietitians with expertise in sports nutrition from other registered dietitians who specialize in other areas of nutrition
myplate
a food guidance system created by the US department of agriculture and based on the 2010 dietary guidelines for americans to help consumers make better food choices
myplate has 5 food groups (largest to smallest): vegetables, grains, protein, fruits, and dairy - amounts estimated in table 9.1
macronutrients
carbohydrate, protein, and fat
micronutrients
vitamins and minerals
dietary reference intake (DRI)
created by the food and nutrition board, institute of medicine, national academies
complete set of nutrient intakes for use when evaluating and planning diets for healthy individuals. listed for the macronutrients and micronutrients, electrolytes, and water
recommended dietary allowance (RDA)
the average daily nutrient requirement adequate for meeting the needs of most healthy people within each life stage and sex
athletes require more than the RDA for protein to build and repair muscle. depending on the sport and the training program, 1.0 to 1.7 g per kilogram body weight of protein is recommended
adequate intake (AI)
the average daily nutrient intake level recommended when a RDA cannot be established
tolerable upper intake level (UL)
the maximum average daily nutrient level not associated with any adverse health effects. intake above the UL increase potential risk of adverse effects. (the UL represents intake from all sources including food, water, and supplements)
estimated average requirement (EAR)
the average daily nutrient intake level considered sufficient to meet the needs of half of the healthy population within each life stage and sex
protein
primary structural and functional component of every cell in the human body.
used for growth and development and to build and repair cells; they also serve as enzymes, transport carriers, and hormones.
intake is essential for maintaining health, reproduction, and cellular structure and function
protein reserves = 15% in structural tissues (skin and blood) and visceral tissues (liver and kidney and in the bones)
amino acids
molecules that when joined in groups of a few dozen to hundreds, form the thousands of proteins occurring in nature
20 variation of amino acids
essential amino acids
9 essential amino acids
body cannot manufacture them
nonessential amino acids
4 nonessential amino acids
can be synthesized by the human body, so do not need to be consumed in the diet
conditionally essential amino acids
8 amino acids
they are typically not essential though they become essential and therefor must be obtained through diet, during times of illness and stress
polypeptide
dipeptide = 2 amino acids together
polypeptide = several amino acids together
chains bond together to form a multitude of proteins with various structures and functions
protein digestability
calculated by how much of the protein’s nitrogen is absorbed during digestion and its ability to provide the amino acids necessary for growth, maintenance, and repair
bioavailability
digestabilibty
acceptable macronutrient distribution range (AMDR)
covers range of protein intake based on grade
children ages 1-4 = 5-20% of total calories
children ages 4-18 = 10-30% of total calories
adults older than 18 = 10-35% of total calories
men and women consume average of 15% of their calories from protein
AMDR shows that when calorie intake is lower, protein needs go up as a % of total calorie intake by approximately 1% for every 100-calorie decrease below 2,00 calories
post exercise protein breakdown
in addition to eating the right amount of protein per day, research supports the idea of athletes consuming sufficient protein right after exercise, when muscle tissue is most receptive to amino acids.
after exercise both muscle protein synthesis and breakdown are increased, though net protein balance is negative when the exercise is done in a fasted state
gluconeogenesis
ketoacids converted to carbohydrate
carbohydrate
serves as a source of energy
not an essential nutrient bc body can break down the carbon skeletons of certain amino acids and convert them into glucose
carbs are composed of carbon, hydrogen, and oxygen
classified into 3 groups according to the number of sugar (saccharide) units they contain: monosaccharides, disaccharides, and polysaccharides
monosaccharides
glucose, fructose, and galactose
single-sugar molecules
glucose
present as circulating sugar in the blood, where it is used as the primary energy substrate for cells
glucose makes up glycogen (polysaccharide) stored in muscle and liver cells
typically combined with other monosaccharides to form various sugars, such as sucrose
fructose
same chemical formula as glucose, but bc atoms are arranged differently, its tastes much sweeter and has different properties
accounts for the sweet taste of honey and occurs naturally in fruits and vegetables
fructose causes less insulin secretion than other sugars
galactose
combines with glucose to form lactose, milk sugar
disaccharides
sucrose, lactose, and maltose
composed of 2 simple sugar units joined together
sucrose
table salt. most common disaccharide
glucose + fructose
occurs naturally in most fruits and is crystallized from the syrup of sugar cane and sugar beets to make brown, white, or powdered sugar
lactose
glucose + galactose
found only in mammalian milk
maltose
glucose + glucose
occurs primarily when polysaccharides are broken down during digestion
also in he fermentation process of alcohol and is the primary carb in beer
polysaccharides
complex carbohydrates, contain up to thousands of glucose units
starch, fiber, and glycogen
glycogen
found in small amounts in human liver and muscle, totaling approximately 15g of glycogen per kilogram body weight, and in animal tissue as a temporary source of stored energy
3/4 of glycogen in the body is stored in skeletal muscle, the remaining 1/4 is stored in the liver
glycogenesis
process of converting glucose to glycogen
glycemic index (GI)
ranks carbohydrates according to how quickly they are digested and absorbed, and therefore raise blood glucose levels, in the 2 hr time period after a meal, compared to the same amount (by weight in grams) of a reference food, typically white bread or glucose, which is given a GI of 100.
GI = [incremental area under the curve for the blood glucose response after consumption of a 25 or 50g carb portion of a test food / incremental area under the curve for the blood glucose response after consumption of the same portion (in g) of standard food] x 100
high GI foods during exercise to provide immediate sources of energy (sugar) for activity and immediately after exercise to more rapidly replenish glycogen stores
glycemic load (GL)
take the amount of carb, g, in a portion of food into account - a factor that also influences glycemic response
more realistic gauge of glycemic response than the GI
GL = [GI of an individual food x grams of carbs per serving of food] / 100
foods with higher GL are expected to lead to greater increases in blood sugar and subsequent insulin release
fiber
diets low in fiber associated with constipation, heart disease, colon cancer, and type 2 diabetes.
recommended intake ranges:
women 21-29g/day
men 30-38g/day
commonly found in fruits, vegetables, nuts, seeds, legumes, and whole grain products
fat
lipid
triglycerides
fats and oils
formed by the union of glycerol with three fatty acids
lipid
include triglycerides as well as related fatty compounds, such as sterols and phospholipids
greatest significance are triglycerides, fatty acids, phospholipids, and cholesterol
saturated fatty acids
no double bonds, and their carbon molecules are saturated with hydrogen
no dietary requirement
unsaturated fatty acids
contain some carbon molecules that are joined together by double bonds, making them more chemically more reactive