nutrition lect 1 cont Flashcards
what is the major source of carbohydrates that we consume ?
plants
Dietary fiber is defined :
non digestible carbohydrates and lignin (a complex polymer of phenyl propanoid subunits) present in plants.
*High fructose corn syrup (HFCS) is :
corn syrups that have undergone enzymatic
processing. to convert their glucose into
fructose
*Composition and metabolism of HFCS
and sucrose. differ that :
HFCS is ingested as a mixture of
monosaccharides.
Recommended intake(AI) for total fiber: :
38g/d for men
25g/d for women
Soluble fibers delay gastric emptying and also :
sensation of fullness
and
reduce peaks of blood glucose following a meal.
Soluble fibers lowers total and LDL cholesterol
levels by
increasing fecal bile acid excretion
and interfering with bile acid reabsorption
The main role of dietary protein:
maintenance of tissue
structure ,function and integrity.
Some amino acids are precursors of biologically active compounds, e.g.
epinephrine, serotonin.
*In case of dietary restriction, dietary protein is used as
energy after removal of amino group and
conversion into glucose or keto acids and fatty acids.
Positive nitrogen balance occur :
child development
pregnancy
recovery from illness (convalescing)
Negative nitrogen balance occur :
Dietary intake is insufficient
One of the essential amino acids is deficient
stress as in injury , sepsis, and cancer
protein loss e.g. nephrotic syndrome, burns
*Quality of proteins is measured by :
ability to provide the essential amino acids required for tissue maintenance.
*Protein Digestibility Corrected Amino Acid Score
(PDCAAS) is:
the standard adopted to evaluate
protein quality.
PDCAAS is based upon :
profile of essential AA and digestibility of protein.
wheat may be combined with kidney beans because :
wheat =(lysine-deficient but methionine rich)
kidney beans =methionine poor but lysine rich)
*The usefulness of the protein is expressed in
terms
net protein utilization (NPU) or
biological value (BV).
*Proteins with high BV or NPU are :
higher quality.
Athletes may benefit from extra protein to maintain muscle mass; a daily intake of about :
1 g/kg/day.
Pregnant or lactating women require
2 g/kg/day to support growth of
their children
Protein consumed in excess of the body’s needs
deaminated
to give carbon skeleton
to provide energy or acetyl CoA for
fatty acid synthesis.
excess protein is eliminated from the body
urinary nitrogen
often accompanied by increased urinary calcium,
and increasing the risk of
nephrolithiasis and osteoporosis.
Protein-energy (calorie) malnutrition (PEM)
in developed countries :
medical conditions that decrease appetite or
alter digestion or absorption of nutrients.
Protein-energy (calorie) malnutrition (PEM) IN developing countries :
Inadequate intake of protein and/or
energy
