MCQ1 Flashcards
why do nutrition recommendations differ?
- for each nutrient
- between sexes
- at different life stages
what do nutrition recommendations aim at?
- prevention of deficiency
- optimisation of health:
UK dietary referance values
- dietary referance values (DRVs)
-Estimated Average
Requirement (EAR)
-Reference Nutrient Intake
(RNI
what are monosacharrides
important energy
source for body
o have the same chemical formula
as glucose but different
arrangement
o often referred to as milk sugar
o same number and type of atoms compared to glucose
polysaccharides
- Made up of many
monosaccharide
molecules
-
health benefits of fibre
o Studies have shown that individuals with adequate
intake of fibre appear to be at lower risk for CVD,
DM2, and colorectal cancer
o Daily consumption of 3 g of the soluble fibre may help to lower blood cholesterol levels as
part of a healthy diet
o The presence of fibre in a food or meal slows down
glucose absorption
o Adequate intake of fibre is suggested to aid in
weight loss or prevent weight gain mainly through satiety or fullness regulation
disaccharides
sucrose, lactose and maltose
sucrose
Sucrose: Glucose + Fructose
o Sweetest disaccharide
o Occurs naturally in fruit and vegetables
and stands for the known table sugar
extracted from sugar cane & sugar beet
maltose
Maltose: Glucose + Glucose
o Produced when
starch is broken down
(e.g., digestion)
o Produced when
grains are fermented
to yield alcohol (e.g.,
making beer by
processing barely)
o Free maltose found
in high concentrations
in barely and maltose
syrups
lactose
Lactose: Glucose + Galactose
o Principal carbohydrate of dairy
o Accounts for over half of the
calories of fat free milk
o Ability of the human body to
digest lactose in the small
intestine may decline after
toddlerhood
what are dietry fats made of?
- free fatty acid
- triglyceride
digestion and absorption overview
- Food containing fat is ingested
- Main site of lipid digestion is small intestine – bile salts emulsify fat – Pancreatic lipase breaks down TGs to
glycerol + FAs - FAs, glycerol and other lipid products are incorporated in
to mixed micelles and cross small intestinal wall - FAs and glycerol reform to make TGs
- TGs and other lipids (e.g. cholesterol) packed with
proteins into chylomicrons - Chylomicrons pass into circulation via the lymph vessels
dietary fats absorption
Whilst in the bloodstream, the TG of the
chylomicrons are hydrolysed to free FAs and
glycerol by lipoprotein lipase found in capillary
endothelial cells
o FAs and glycerol pass through the capillary walls
to be stored as fats in the adipose tissue, used
by cells as energy (e.g., oxidation by muscle
cells) or released into the systemic circulation
returning to the liver
amino acids- chemical structure
o Proteins are macromolecules composed of amino acids, i.e., amino acids are protein’s building blocks
o There are around 20 different amino acids in animal and plant foods – all are required to form the
different proteins found throughout the human body
o Each amino acid consists of a central carbon atom (C) connected to a side chain (R), a hydrogen atom (H),
a nitrogen atom (N) and a carboxylic acid group (-COOH)
o Amino acids differ from each other by which specific side chain (R) is bonded to the carbon centre
amini acids- nutritional classification
o Based on their nutritional aspects, 11/20 amino acids are called nonessential
(i.e., body can create them) – the remaining 9 amino acids are called
essential and must be obtained from the diet (i.e., body cant create them)
o The nutritional value of a
protein is dependent on what
amino acids it contains
regarding their essentiality and
in what quantities
o Sometimes during infancy, growth,
and in disease the body cannot
synthesize enough of some of the
nonessential amino acids (i.e.,
they are required in the diet) –
these types of amino acids are called conditionally essential
