Ch. 4 Carbohydrates
classification
monosaccharides
contain carbon, hydrogen, oxygen
Ch. 5 Proteins
nutritionists recommend carbs should represent 50% of total calories
polysaccharide: complex carbohydrates; contain a minimum of 10 units of various simple sugars
simple sugars containing 2-6 carbons
glucose
fructose
galactose
grapes, oranges, dates, some vegetables like corn, corn syrup
principal product of digestion of disaccharides and polysacchardies
only sugar transported through bloodstream that can nourish all cells in the body
also called dextrose or corn sugar
also known as levulose
found in honey and fruits
product of the digestion of sucrose
absorbed without further digestion
rarely found free in nature
product of lactose digestion
Disaccharides: contain 2 simple sugars joined together; 12 carbons
sucrose
maltose
lactose
most common form is granulated table sugar
sugar found in milk
contains two molecules of glucose
contains galactose and glucose
dose not occur naturally
polysacchardies
glycogen
dietary fiber
starch
cereal grains, roots, vegetables, legumes
storage form of energy in humans
stored in muscle and liver
nondigestible components of food that has desireable health effects
soluble dietary fibers: become viscous in solution
resistant starch: form of dietary fiber; cannot be digested
functional fiber: added during manufacturing process
total fiber: sum of dietary fiber and functional fiber
contain more than 10 monosaccharides
physiologic roles of carbohydrates
normal fat metabolism
protein sparers
conversion to amino acids
intestinal bacteria
fat storage
gastrointestinal motility
energy
hyperglycemia: blood glucose levels greater that 130 mg/dL before meals or greater that 180 mg/dL 2 hours after meal
hypoglycemia: blood glucose level less than 70 mg/dL
issues
obesity
cardiovascular disease
carbohydrate deficiency
studies have concluded that dietary sugars are not associated with causing illness or chronic disease, including obesity
some studies indicate association between higher intake of whole grains with healthier body weights and fate stores
dietary guidelines - fiber rich diet to help in management of obesity
association between diets rich in added sugars and the onset of heart disease risk factors
extremely low carb diets may lead to ketosis
when complex carbs are eliminated, an insufficient intake of B vitamins, iron, and fiber may occur
Dental caries
dental erosion can occur with frequent exposure to any liquid with a pH lower than 4.2
extent of erosion caused by beverages from greatest to least: energy drinks, sports drinks, regular soda, diet soda
glucose can be used for energy by oral bacteria in plaque biofillm
sucrose, other disaccharides and monosaccharides promote bacterial growth
structure
amino acids are building blocks of proteins
all proteins are made from combinations of 20 amino acids
large molecular structures
amino acids
proteins consumed are hydrolyzed by enzymes in the small intestine into individual amino acids for absorption and utilization
combine with each other to make long chains
two amino acids combine with each other to make dipeptide
classification
indispensable amino acids - 9 required in diet
dispensable amino acids - essential for the body, but they can be produced from indispensable amino acids
in certain nutritional or disease states or stages of development, several dispensable amino acids become indispensable or conditionally indispensable
high quality protein - when 9 indispensable amino acids are provided from a food in amounts adequate to maintain nitrogen balance and permit growth
low-quality protein - if quality of one or more indispensable amino acids in a food is insufficient for optimal protein synthesis
nitrogen balance
the balance in reactions in which protein substances are broken down or destroyed and rebuilt
Healthy individuals excrete (in feces, urine, and from
skin) same amount of nitrogen as consumed
Negative nitrogen balance: Person with a burn or illness excretes more
nitrogen than is ingested
Positive nitrogen balance: In periods of growth (childhood or pregnancy),
more protein retained than lost
Physiologic roles
regulation of fluid balance
resistance to disease
production of essential compounds
transport mechanisms
repair of body tissues
energy
generation of new body tissues
sources of protein
1 oz of cheddar cheese = 7g
1 cup of oatmeal = 6g
1 oz of chicken = 9g
1 cup of cooked white rice = 4g
1 cup of milk = 8 to 9g
underconsumption of protein
hair color change and sparse hair
anemia
fatty liver
lethargy
edema of extremities, torso, face
cracked, peeling, infection-prone skin
Kwashiorkor - occur from lack of quality protein intake despite adequate amount of calories
opportunistic infections
at risk - children 18- 24 months