Exam 1 Flashcards
What is nutrition?
the study of dietary intake and behavior as well as the nutrients and constituents in food including their use in the body and influence on human health
Registered Dietitian Nutritionist
Has met the minimum academic and professional requirements to qualify for the credential “RD” or “RDN”
Professional organizations of RD/RDNs
Academy of Nutrition and Dietetics (AND)
What does food provide?
- Nutrients
- Energy
- Other chemical components
What are nutrients?
Chemical substances that provide nourishment necessary for growth and the maintenance of proper body functioning
What are essential nutrients
Nutrients that the body cannot produce or produce in sufficient amounts to meet the body’s needs and must be consumed through diet
What are nonessential nutrients?
nutrients that can be manufactured by the body are considered nonessential - but still have vital roles in body processes
What are phytochemicals?
biological active beneficial compounds in plant foods; provide color, aroma, and flavor
What are the 6 classes of nutrients required for the body to function?
- Carbohydrates (macronutrient)
- Protein (macronutrient)
- Fats (lipids) (macronutrient)
- Vitamins (micronutrient)
- Minerals
- Water
Macronutrients include…
- Carbohydrates
- Lipids
- Protein
- Water
Micronutrients include…
- Vitamins
2. Minterals
Why do we need vitamins and minerals?
for the conversion of carbohydrates, proteins, and fats into energy
What is the process of digestion?
- Extracts macronutrients, micronutrients, and phytochemicals from food
- Absorbed and utilized by the body
What is malnutrition?
Inadequate, excessive, or unbalanced nutrient intake can result in malnutrition (“bad” nutrition)
What is undernutrition?
results from inadequate intake of one or more nutrients
What are DRIs?
Recommended daily levels of intake that not only meet the nutrient needs of almost all healthy people (97-98%), but also promote health and help reduce the risk of chronic disease
What four values of nutrient intake does DRI include?
- Estimated average requirements (EAR)
- Recommended dietary allowances (RDA)
- Adequate Intake (AI)
- Tolerable upper intake levels (UL)
What do nutrient values vary by?
factors as age, body size, gender, genetic traits, growth status
What is the most prevalent nutrient deficiency?
iron
What are the different scientific methods of studying nutrition?
randomized controlled experiment, epidemiological study, experimental model systems
What is evidence-based medicine?
The conscientious, explicit, and judicious use of the current best evidence in making decisions about the health care of individuals
What is the process of digestion?
extracts nutrients from foods to supply the needs of cells, tissues and organs
What is the primary function of the digestive system?
to break down nutrients in food into compounds small enough to be absorbed and utilized by the body
What are carbohydrates broken down into?
single sugar units
What are proteins broken down into?
amino acids
What are fats broken down into?
fatty acids and glycerol
What are the organs of the GI tract?
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intestine
How long is the GI tract?
26-30 ft. long
Where is most of the GI tract located?
small intestine
What else does the digestive tract include?
accessory organs that secrete fluids that aid in digestion
What are the 4 basic stages in the process of digestion?
- Ingestion
- Digestion
- Absorption
- Excretion
Though what 2 processes is digestion accomplished?
- Mechanical digestion
2. Chemical digestion
What is mechanical digestion?
the physical fragmentation of foods into small particles
Where does mechanical digestion begin? and what happens?
begins in the mouth
- teeth masticate
- tongue mixes
- food bolus formed
Why do kids like bland food?
have more taste buds; we lose taste buds as we age
What two types of muscle contractions mix food with digestive fluids and propel food along the length of the GI tract?
- Peristalsis
2. Segmentation
What is peristalsis?
propulsive contractions move food forward from esophagus to anus
What is segmentation?
uncoordinated contractions that mix intestinal content with digestive fluids and bring nutrients in contact with absorptive surface
How does peristalsis work?
- moves food forward through GI tract
- mechanically churns food in the stomach into fragments
- food bolus passes from the esophagus into the stomach
- food churned into fragments that disperse in gastric fluid
- semi-liquid mass (chyme) slowly released into small intestine
How many cups of food can the muscular sack hold?
4 cups
What happens in mechanical digestion in the intestine?
segmentation mixes intestinal content with digestive fluids and brings nutrients in contact with intestinal absorptive surface
How does chemical digestion begin?
- Begins in the mouth as saliva mixes with food
- Contains enzymes that initiate chemical reactions in the breakdown of foods
What begins the digestion of carbohydrates?
amylase
How do enzymes help in chemical reactions?
Enzymes speed up the rate at which a chemical reaction produces new compounds
Where does chemical digestion continue after the mouth
in the stomach as gastric juices mix with food
What do gastric juices contain?
- hydrochloric acid
- enzymes protease and lipase
- mucus
how does mucus help in the stomach?
- lubricates food
- protect stomach lining
What is the primary site for digestion and absorption?
the small intestine
What are villi?
the structural features of the small intestine increase its surface area for absorption
What is the next step in chemical digestion after the stomach?
secretions from the accessory organs participate in chemical digestion in the small intestine
What happens once food is absorbed into the small intestine during chemical digestion?
the small intestine brush border nutrients are distributed to cells of the body
What are the two parts of the circulatory system important for digestion?
- blood
2. lymphatic system
What goes into your blood from chemical digestion?
carbohydrates, amino acids, minerals, and water-soluble vitamins
What goes into your lymphatic system from chemical digestion?
most fats and some vitamins
What happens to any undigested nutrients?
remain in the chyme are passed into the large intestine
How does the large intestine differ from the small intestine?
- Much smoother structure - no villi
- Will extract fluids, some vitamins
- Location of bacteria
How many different species of bacteria are in the large intestine?
over 1,000
What do bacteria in the large intestine do?
- Feed on undigested fiber and starch
- reduce activity of disease causing bacteria
What are probiotics?
help restore or maintain a healthy balance of “friendly” bacteria in the GI tract
What are sources of probiotics?
fermented foods like yogurt, soy, miso, sauerkraut
What are prebiotics?
non-digestible carbohydrates used by probiotics to boost growth
What are sources of prebiotics?
chicory, whole-grain rye, oats, wheat, barley, leeks, onions, and garlic
Where does the digestio of starch begin?
in the mouth with amylase
What is your glycemic index?
how rapidly a food increases your blood sugar
What are starches?
complex carbohydrates
What are whole grains?
contain the endosperm, germ, and bran in original proportions
What are refined grains?
stripped of germ and bran, leaving only endosperm
What are enriched grains?
some nutrients lost in processing are added back
What does the Dietary Guidelines for Americans recommended for whole grains?
Consume at least half of grains as whole grain
What does USDA MyPlate recommended for whole grains?
Look for whole grains as first ingredient in food products
What does the American Heart Association recommended for whole grains?
Look for products with total-carbohydrate-to-fiber ratio of less than 10:1
What is the recommended carb-to-fiber ratio?
10:1
Where are significant sources of carbs found?
in plant foods as well as milk and milk products
What is a rich sources of carbohydrates?
whole grains
Where are whole grains found?
- Found in all plant foods
- Also present in dairy foods
What is the chemical composition of carbs?
contain carbon, hydrogen, and oxygen (CHO) arranged as one or more sugar molecules
Are carbs a macronutrient or micronutrient?
macronutrient
What is a major fuel source of the body?
carbohydrates
How many calories per gram are in carbohydrates?
4 calories per gram
Are carbohydrates a source of energy for all cells of the body?
True
Do carbohydrates have vital functions in nutrition and health?
True
What are carbohydrates an indispensable source of energy for?
brain, red blood cells, and exercising muscles
Carbohydrates don’t add sweetness and flavor to foods.
False
Carbohydrates reduce the use of protein for energy.
True
Carbohydrates are not a good source of fiber.
False
What is the acceptable macronutrient distribution range for carbohydrates?
45-65% total calories
What is the acceptable macronutrient distribution range for protein?
10-35%
What is the acceptable macronutrient distribution range for lipids?
20-35%
What are simple carbohydrates?
made up of one or two sugar units
What are the monosaccharides?
glucose
fructose
galactose
What are the two kinds of simple carbohydrates?
monosaccharides and disaccharides
What are the disaccharides?
sucrose
lactose
maltose
What are disaccharides?
two linked sugar units
What is sucrose?
glucose+fructose
What is lactose?
glucose+galactose
What is maltose?
glucose+glucose
What are the 2015 Dietary Guidelines for Americans concerning added sugar?
recommend consuming <10% of total calories from added sugar
Why is sugar considered “empty calories”
have no minerals, vitamins, or fiber
What are added sugars?
- Should comprise less than 10% of total calories
- Are considered empty-calories and often found in ultra– - - Contribute directly to dental caries (cavities)
- Do not include sugars found in fruit and milk
What are the functional contributions of added sugars?
- texture, color, browning capability of baked goods
- preservation (extended shelf life)
What is the problem with added sugars?
- easy to overeat
- increase energy density
- decrease nutrient density
- contribute to excess calorie intake and obesity
Why moderate sugar intake?
- Foods with simple sugars are generally poor sources of nutrients
- May displace more nutrient dense foods
- Do little to promote satiety
- Many foods high in sugars are also high in fat and total calories – thus may contribute to positive energy balance
- Likelihood that diets will be insufficient in vitamins and minerals increases with sugar intake
- Sweets consumption promotes tooth decay
- Correlates with increased risk cardiovascular disease-
Why does sugar promote tooth decay?
due to acids produced by bacteria in the mouth that feed on sugar
- Exposure time important variable
- “stickier” sweets more apt to promote decay
What is lactose intolerance?
low lactose activity
What are the gastrointestinal symptoms of lactose intolerance?
diarrhea, gas, cramps, abdominal pain
What are some treatments for lactose intolerance?
- Decrease dairy intake
- Lactose-free dairy products or lactose pills
- Add calcium-rich and vitamin D foods or supplements
What are the two types of sugar alternatives?
non-nutritive and nutritive sweeteners
Who regulars sugar alternatives?
FDA
What are the benefits of nutritive sweeteners?
- Provide calories, but fewer than sugars
- Reduced absorption
- Include sugar alcohols (polyols)
What are the benefits of non-nutritive sweeteners?
calorie free
What’s the problem with nutritive sweeteners?
poorly absorbed and do not promote tooth decay
What’s the problem with non-nutritive sweeteners?
hundreds of times sweeter than sugar
What are complex carbohydrates?
composed of three or more monosaccharides linked together
Whare are 3 complex carbohydrates?
- starch
- fiber
- glycogen
What are 3 examples of complex carbohydrates?
- grains
- legumes
- some vegetables
What are 3 examples of simple carbohydrates?
- fruits
- many vegetables
- milk
How do we digest complex carbohydrates?
borken down into individual monosaccharides with enzymes
What ezymes are used to break down complex carbohydrates?
- amylase
- sucrase
- maltase
- lactase
Where does carbohydrate digestion being?
the mouth
How is glycose stored?
as glycogen or in fat
What are the 3 fates of glucose?
- immediate energy source to all cells
- converted into glycogen (glycogenesis)
- Converted into fat
Where is glucose stored when it is converted to fat?
adipose tissue
Where is glycogen stored?
liver and skeletal muscle
Where is there unlimited storage capacity for glucose?
adipose tissue
Where is there limited storage space for carbohydrates/
liver and skeletal muscle
Liver glycogen
broken down to maintain blood glycose levels
Muscle glycogen
broken down to provide energy to do work
What is the adequate intake of fiber for males 19-50?
38grams/day
What is the adequate intake of fiber for women 19-50?
25grams/day
What is the average US intake of fiber?
15grams/day
What are the benefits of fiber?
- Soluble fiber may reduce the risk of cardiovascular disease
- High-fiber foods promote satiety and may reduce the risk of obesity
- High intakes of insoluble cereal fiber may reduce the risk of type 2 diabetes
- Soluble fiber slows the increase in blood glucose following carbohydrate ingestion
- High insoluble fiber intake softens stools and reduces the occurrence of constipation
How is fiber classified?
by its solubility
What does fiber’s solubility reflect?
its health benefits
What is soluble fiber?
- Form viscous gels
- Can lower blood cholesterol
- Slower stomach emptying
- Slows digestion and absorption
- Reduces the risk of coronary artery disease
What is insoluble fiber?
- Increases fecal bulk
- Reduces constipation
- Softens stool and decreases constipation
- Decreases hemorrhoids and diverticular disease
What are the 4 classes of lipids?
- fatty acids
- triglycerides
- sterols
- phospholipids
What are lipids?
- Structurally diverse group of molecules
- Contain carbon, hydrogen, and oxygen
- Generally insoluble in water
How do lipids benefit bodily functions?
- component of cell membranes - give flexibility and integrity
- fat supply a concentrated source of energy and fat-soluble nutrients
- Facilitate the transportation of nutrients
- enhance the absorption of fat-soluble vitamins
How many calories per gram are in lipids?
9 calories/gram
What are the fat-soluble vitamins?
A, D, E, K
How do fats contribute to us feeling full?
- Fats stay in stomach longer
- Are absorbed over a longer period of time
What are the roles lipids play in the body and in foods?
- Primary source of body’s energy reserves
- Adipose tissue cushions, protects, and insulates the body’s organs
- Fats contribute to the sensation of feeling full
- Fats increase the flavor and palatability of foods
- Fats contribute to the texture and aroma of foods
How many calories is 1 pound of fat?
3500
What are fatty acids the primary components of?
- triglycerides
- phospholipids
What are characteristics of fatty acids?
- Consist of a chain of carbon atoms with hydrogen atoms attached to each carbon
- Differ in chain length and saturation
- Saturation = how many hydrogen atoms fill the available carbon bonds
What are the two types of fatty acids?
- saturated
2. unsaturated
What are characteristics of saturated fatty acids?
- Fully hydrogenated
- All carbons “saturated” with hydrogen
- No double bonds
What are food sources of fatty acids?
- solid at room temperature
- animal origin
- tropical oils
What are characteristics of unsaturated fatty acids?
- fewer hydrogen atoms
- contain one or more double bonds
- tend to be liquid at room temperature
What are the two types of unsaturated fats?
- monounsaturated fat
2. polyunsaturated fat
What are monounsaturated fatty acids?
one double bond or point of unsaturation
what are polyunsaturated fatty acids?
more than one point of unsaturation or more than one double bond
What are some food sources of monounsaturated fatty acids?
Olives, avocados, and some nuts, like peanuts and almonds
What are food sources of polyunsaturated fats
most vegetable oils
What are triglycerides commonly called?
fats
What are triglycerides?
- A three-carbon glycerol molecule with three fatty acids attached
- Make up 95% of lipids in our food and 99% of the stored fat in our bodies
What is cholesterol
a sterol produced by the liver that is not an essential nutrient
What is a distinguishing characteristic between plant and animal cells?
the presence of cholesterol
Where is cholesterol found?
foods of animal origin
Where is cholesterol found in our bodies?
every cell
What are the functions of cholesterol in our bodies?
- Critical component of cell membranes
- Not present in cell membranes of plants
- Precursor for the synthesis of bile acids, vitamin D and steroid hormones
- Does not provides calories
What is unique about phospholipids?
unlike other lipids, the unique structural arrangement allows phospholipids to suspend fat in water
What is lecithin?
a phospholipid found in the body as well as in food products
Where can you find lecithin?
in egg yolks, liver, and some plant foods
Is lecithin an essential nutrient?
no
What is the role of lecithin?
Functions as an emulsifier which keeps water and lipids from separating
Where does most lipid digestion occur?
in the small intestine
What facilitates lipid digestion in the small intestine?
- bile acids
- emulsification
- lipases
How much and by what means does lipid digestion occur in the mouth and stomach?
limited amount, by lipases
Are lipids soluble in water?
no
How are lipids absorbed into the body?
- require carrier for transport
- Dietary lipids incorporated into transport particles for absorption
Where are lipids absorbed in the body?
Absorbed initially into lymphatic system which delivers to bloodstream
How are lipids transported in the blood?
lipoproteins
What are the 4 classes of lipoproteins?
- chylomicrons
- very low-density lipoproteins
- low-density lipoproteins
- high-density lipoproteins
How are lipoproteins classified?
by density and function
What are chylomicrons?
the biggest lipoprotein that is the primary carrier of lipids in our diet
What are LDLs?
primary carrier of cholesterol to all cells
Where are LDLs made?
liver
What is bad cholesterol?
LDLs
What is the problem with elevated levels of LDLs?
associated with increased risk of heart disease
What are HDLs?
lipoproteins that carry cholesterol from cells back to liver and contain higher proportion of protein
What is good cholesterol?
HDL
What are high levels of HDL associated with?
lower heart disease risk
What is another name for HDL?
reverse cholesterol transporter
What affects the risk of cardiovascular disease?
concentrations of total cholesterol, HLD cholesterol, LDL cholesterol, and triglycerides in the blood
What essential fatty acids can the body not synthesize?
omega 6 and omega 3
What is omega-6 fatty acid called?
linoleic acid
What is omega-3 fatty acid called?
linolenic acid
What is the most abundant polyunsaturated fat in the diet?
linoleic acid/omega-6
What are the primary sources of linoleic acid?
cooking oils, salad dressings, nuts and seeds
What is the most abundant polyunsaturated fat in the American Diet?
linoleic acid
Do Americans consume enough linolenic acid?
no
What is another name for omega-3?
linolenic acid
What is linolenic acid required for?
- Structural component of cell membranes
- Synthesis of hormone like compounds (eicosanoids)
- EPA
- DHA
Where is linolenic acid found?
walnuts, flaxseeds, canola oil, soybeans, chia seeds
What are the best sources of linolenic acid?
marine oils (cold water fish) due to content of DHA and EPA
What are omega-3 fatty acids associated with?
decreased risk of heart disease and improve brain function
Where are DHA and EPA found?
fish oils
Where do most Americans consume fat from?
hydrogenated making unsaturated fat more solid and stable
What is hydrogenation?
- Adding hydrogen to an unsaturated fat makes it saturated (full of hydrogen)
- Makes an unsaturated fat more solid and stable
- Can improve taste and texture
How are trans fats made?
partial hydrogenation
How are trans fats chemically altered?
Altering from natural “cis” to a “trans” chemical configuration
What is the problem with trans fats?
increase risk of heart disease more than any other type of fat
What are dietary strategies to reduce the risk of heart disease?
- Consumption of plant sterols or stanols
- Plant-based diets
- Nut consumption
- Oily, cold-water fish
- Whole grain oats
- Moderate alcohol consumption
- Substituting unsaturated oils for saturated fats
2015 Dietary Guidelines for Americans
- DGAs recommend limiting saturated fat to < 10% of total calories
- Strictly limit intake of trans fatty acids
- In contrast to earlier editions, the 2015 guidelines do not establish specific limits for dietary cholesterol, but qualify that eating as little as possible is advisable within a healthy eating pattern
Benefits of the Mediterranean diet
- Different lifestyle and different diets
- High in monounsaturated fats
- Healthy ratio of omega-6 to omega-3 fats
- High in fiber, antioxidants, and polyphenols
- Moderate consumption of wine with food
- Consumption of fish and less other meat
What elements make up protein?
C, H, O, N
What is the RDA for protein based off of?
body weight
How much protein do we need?
0.8g/kg body weight
What roles does protein play in the body?
structural material
growth, maintenance, repair
energy source
critical function
What are some of the critical function of protein?
- Enzymes
- Hormones
- Antibodies
- Fluid balance
- pH balance
- Transporters
- Blood clotting
What structural material does protein make up?
- Muscle
- Bone
- Hair
- Skin
- Fingernails
What is different about protein’s composition?
N and amino acids
Where do Americans get most of their protein from?
animal products
what are the building blocks of protein?
amino acids
how are proteins formed?
amino acids linked together
what kind of bonds hold amino acids togther?
peptide bonds
what breaks apart the bonds holding animo acids together?
proteases
How many different kinds of amino acids are there?
20
How many different proteins are in our body?
over 22,000
How many essential amino acids are there?
9
how many nonessential amion acids are there?
11
Why do we need the essential amino acids?
for protein synthesis
What determines the function of proteins?
shape
What is denaturation?
alters shape and function of proteins
What causes denaturation?
heat, light, change in pH, alcohol or motion
Why is denaturation important?
digestion of protein
what alters the shape and function of proteins?
denaturation
What happens in the stomach when digesting protein?
acidic juices, pepsin
What happens in the small intestine when digesting protein?
pancreatic protesases
absorpotion of amino acids
What is protein turnover?
proteins in the body constantly being broken down and reassembled
What do amino acids produce when they are chemically altered?
proteins synthesize
synthesized into glucose or fat
Metabolized as a source of energy
What is protein quality?
measure of how well a protein food meets our needs for protein synthesis
What is protein quality based on?
proportion of essential Amino Acids
What are complete proteins?
contain all 9 essential amino acids
What are incomplete proteins?
lack one or more essential amino acid
What are complementary proteins?
comcine two incomplete proteins to make complete protein
Is it possible to meet protein needs when consuming a plant based diet?
yes, if consuming enough calories and carefully planning a variety of foods?
What are the two types of protein deficiency?
Kwashiorkor
marasmus
What is kwashiorkor?
inadequate protein intake causes edema (swollen belly)
What is marasmus?
definiciency in protein and calorie intake causes “skin and bones” appearance
