HC 1- MACRONUTRIËNTEN
Energie = De mogelijkheid om arbeid te verrichten – warmte, mechanisch, elektrisch, chemisch
Metabolisme:
- Anabolisme = Opbouw, van kleine -> grote moleculen
o Kost energie (ATP) – bv. fotosynthese
- Katabolisme = Afbraak, van grote -> kleine moleculen
o Levert energie (ATP) – bv. celademhaling
Kilocalorie = Eenheid om energie te meten: energie (warmte) nodig om temperatuur van 1 kg. water
1 graden Celsius te doen stijgen – 1 kcal = 4.18 kJ (1 newton/meter x 1000)
Energieprocent = Aandeel in aantal calorieën dat het eten levert.
- Meestal gebruikt voor aandeel macronutriënten en verschilt per populatie.
Energiedichtheid = energie/ gram – per voedingsmiddel/drankje/maaltijd
- Meeste invloed: Gehalte water en vet
Koolhydraten:
Belangrijkste energiebron – 45% van de energie-inname
- ADH: 40-70 van energie% uit KH
o Te laag: Spierweefselafbraak (eiwit -> glucose)
o Te hoog: Mogelijk te weinig eiwitten/vetten
Metabolisme KH:
- Koolhydraten (voeding) -> monosachariden – galactose, fructose & glucose
- Monosaccharides enter the capillaries of the intestinal villi travel to liver via the portal
vein galactose and fructose are converted to glucose in the liver glucose -> glycogeen
o Glucose glycogen (1/3 liver + 2/3 muscles)
Regulatie bloedsuiker:
High blood sugar: Promotes insulin release from the pancreas, which stimulates glycogen formation
or the glucose uptake from blood.
Low blood sugar: Promotes glucagon release from the pancreas, which stimulates glycogen
breakdown.
,Te veel koolhydraten:
- Carbohydrate -> glucose -> Used for: liver + muscle glycogen stores and body fat stores
Energiebronnen 2-3 uur na maaltijd:
- Liver and muscle glycogen stores -> glucose -> energy for the brain, nervous system and red
blood cells or energy for other cells.
- Body fat stores -> fatty acids -> energy for other cells
Energiebronnen bij langdurig vasten (24 uur):
- Glycogeen voorraad uitgeput – afbraak eiwitten EN VET:
Gestoorde bloedglucose regulatie: Diabetes
- Type I – Immune cells destroy ß-cells -> pancreas cannot secrete insulin
- Type II – Pancreas secrete sufficient insulin -> insuling resistance
Gevolg: Glucose cannot enter cells -> glucose increase in blood stream
Glycemische index (GI):
- Snelheid bloedglucose stijging na eten, max. hoogte glucose, snelheid daling glucose.
Monosacchariden – Glucose, fructose, galactose
Disacchariden – Maltose, sucrose/sacharose, lactose
Oligosacchariden – Bv. raffinose, stachyose
- Niet verteerd in dunne darm, maar omgezet door bacteriën in dikke darm – veel in
moedermelk.
o Nieuwe richtlijnen: Consumptie peulvruchten verlaagt LDL
Polysacchariden
- Glycogeen – opslag glucose mens/dier Sterk vertakt, veel plaatsen voor enzymatische
omzettingen indien glucose nodig.
- Zetmeel – opslag glucose in plant Polymeer van > 3000 glucosemoleculen
o Verteerbaarheid speelt een rol
Verteerbaar zetmeel = 4 kcal / gram (atwater)
Resistent zetmeel = <4 kcal / gram
Bv. groene banaan minder energie dan rijpe banaan
- Voedingsvezels – onverteerbaar plantenvoedsel-
o Onoplosbaar: Niet gefermenteerd door bacteriën in dikke darm
Nauwelijks/geen energie – indeling op basis van oplosbaarheid in water
Effecten in lichaam:
Houdt water vast- meer bulky feces
Versnelt darmpassage
Gezondheidseffecten:
Helpt tegen constipatie
Preventie diverticulosis, aambeien
, Mogelijk rol in gewichtscontrole (energie omlaag, verzadigingsgevoel
omhoog)
o Oplosbaar: Deels gefermenteerd door bacteriuen dikke darm
Veel in: Fruit, groenten, peulvruchten
Effecten in lichaam:
Cholesterolverlagend
Vertraging passage voeding door maagdarmstelsel -> vertraging
glucose absorptie
Vocht vasthouden en zachtmaken van feces
Gezondheidseffecten:
Geassocieerd met preventie H&V ziekten en DM2
o Fermentatie: Olisacchariden & deels oplosbare vezels – omzetting in kortketenige
vetzuren en gas, vetzuren als energiebron.
Zoetstoffen:
- Intensief – opgebouwd uit aminozuren en methanol (bv. aspartaam)
o Geen aanwijzingen voor schadelijke effecten gezondheid
H1.2 – THE NUTRIENTS
Nutrients: Substances the body uses for the growth, maintenance and repair of its tissues.
6 classes:
Nutrient Organic Inorganic Energy- Macronutrien Micronutrient
yielding t
Carbohydrate X X X
s
Lipids X X X
Proteins X X X
Vitamins X X
Minerals X X
Water X
The Energy-Yielding Nutrients: Nutrients that can be used to provide energy
- Energy measured in calories
o Carbohydrates – 4 kcal/ gram
o Proteins – 4 kcal/gram
o Lipids – 9 kcal/gram
Has a greater energy-density
- Alcohol provides energy as well – not a nutrient (yields 7 kcal/gram)
- Energy in the body: Due to breaking of the bonds – released as heat/electrical impulses
Not used: Storage
Other roles: Builds the body’s tissues + regulates activities.
Vitamins: Facilitate the release of energy + participate in activities throughout the body
- Vulnerable to destruction by heat, light and chemical agents – handle with care
Minerals: Influences fluid balance and distribution + in teeth/bones
- 16 essential nutrients
- Indestructable, can be bound to substances that interfere with the body’s ability to absorb
them.
Water: Provides environment in which nearly all body’s activities are conducted
- Metabolic reactions, supplies medium for transport (to/from cells).
, H4 – THE CARBOHYDRATES: SUGARS, STARCHES AND FIBERS
4.1. THE CHEMIST’S VIEW OF CARBOHYDRATES
Simple carbohydrates: The sugars
Monosaccharides – single sugars
- Chemical differences in arragements – accounts for difference in sweetness
- Types:
o Glucose- essential energy source for all body’s activities
o Fructose- sweetest of the sugars
o Galactose- only in very small amounts
Disaccharides – composed of pairs of monosaccharides
- Chemical reactions:
o Condensation – to make a disaccharide- H20 created
o Hydrolysis – to break a disaccharide- H20 added
- Types:
o Maltose (glucose + glucose) – produced when starch breaks down during
carbohydrate digestion/during fermentation process
o Sucrose (glucose + fructose)
o Lactose (glucose + galactose)
Complex carbohydrates: Starches and fibers
Polysaccharides – composed of chains of monosaccharides
- Types:
o Glycogen – stores glucose
o Starches – how plant cells store glucose
o Fibers – structural parts of plants
Dietary fibers: Nonstarch polysaccharides – not digested by human digestive
enzymes (some by GI tract bacteria)
Soluble fibers – dissolve in water, form gels (viscous) and are easily
digested in the colon (fermentable)
Insoluble fibers – don’t dissolve in water, don’t form gels and are less
readily fermented.
Functional fibers – if they have beneficial health effects (when extracted
from plants/manufactured and added to food/supplements)
Total fiber = dietary fibers + functional fibers
Resistant starches – escape digestion and absorption
Phytic acid: non-nutrient component of plant seeds – binds minerals in
insoluble complexes – excreted unused by the body
4.3. GLUCOSE IN THE BODY
Primary role: Supply cells with glucose for energy
- Adheres to molecules:
o Protein – change proteins shape and function glycoproteins
o Lipids – sugars alter the way cells recognize one another glycolipids
Carbohydrate Metabolism:
- Storing glucose as glycogen
- Using glucose for energy
- Making glucose from protein – gluconeogenesis (protein glucose)
o Protein-sparing action
- Making ketone bodies from fat fragments
o Ketone provides alternative fuel source during starvation
Ketosis – accumulation of ketones when production exceeds their use
