CHOs, Protein, Energy Flashcards
Carbohydrates contain
carbon, hydrogen, oxygen
Common monosaccharides
glucose
fructose
galactose
common disaccharides and enzyme needed to cleave them
maltose (2 glucoses) - maltase
sucrose (glucose and fructose) - sucrase
lactose (glucose and galactose) - lactase
Hydrolysis rxn definition
need water to cleave disaccharide
Condensation rxn definition
releases water to make a disaccharide
fatty acids with ____ solidify first if we start lowering the temperature
least double bonds
- think of extremophile membranes: lots of 2x bonds to keep them liquid at low temperatures
Simple sugars are?
monosaccharides and disaccharides
Oligosaccharides
3-10 monosaccharides
ex, prebiotics - encourage healthy bacterial growth in large intestine
Polysaccharides
> 10 monosaccharides
complex carbohydrates
non-fibre polysaccharides
STARCH
glycogen vs starch
glycogen is storage form of glucose in animals and humans and starch is the plant version
Carbohydrate sources
make up 45-65% of our diet
found in:
grains
vegetables (carrots, corn, peas, potatoes *starch)
fruit (most contain simple sugars, bananas have starch)
milk and alternatives (milk *lactose, legumes *soy)
VIRTUALLY NONE IN MEAT AND ALTERNATIVES
Which place in the world has most kcal coming from carbohydrates?
Africa: >80% – Casava vegetable
The caribbean is next with ~65%
DRI for fibre
14g / 1000kcal intake / day
Pattern of carbohydrate intake in NA
last 120 yrs
inc animal protein, inc fat and dec carbohydrates
BUT inc in refined carbos (white flour and sugar) and dec the good carbos (which retains fibre from original product)
CHO digestion
- mouth: salivary amylase begins starch breakdown into maltose, speed of eating determines how much breakdown occurs
- stomach: HCl denatures amylase
- small intestine: CHO enters as maltose, sucrose, lactose, and starch
- pancreatic amylase breaks starch into maltose
- maltase, sucrase, lactase break down their disaccharides
- ends with 4 glucose, 1 fructose, 1 galactose
CHO absorption
monosaccharides absorb through mucosa into HPC via portal vein, into liver for filtering
Monosaccharide metabolism in the liver
- what does it provide?
galactose and fructose get converted to glucose:
- provides kcal for liver
- liver stores extra as glycogen
- liver converts needed to one of 11 non-essential AA
- any more excess converts to fat (VLDL)
- glucose needed sent into blood to inc BS
Glucose uses in blood
- energy/fuel for most body cells (brain, CNS, RBCs)
- stored as muscle glycogen (energy when contracting)
Glucose basic facts
- very few food sources of JUST glucose
- not essential
- primary energy source for brain, CNS, RBCs, kidney cortex
insulin release occurs when?
after a meal, glucose released into blood, triggers insulin inc as BS increases
- pancreas releases insulin: anabolic hormone, allows for glycogen production, use of glucose and fat production
Effects of insulin release
- facilitates uptake of glucose from blood to cells: once glucose is uptaken in cell, cell releases insulin
- stimulates glycogen production
- returns BS to normal basal levels
Basal blood glucose levels
4.5 - 5.5 mmol
What happens when BS drop?
hunger pangs
- insulin levels to drop, glucagon levels inc in pancreas
- glucagon metabolizes glycogen to glucose, released into blood
- blood glucose rises and hunger response temporarily curbed
2019 food guide iterations showed which nutrient needs not met?
K, Ca, D
type 2 diabetes global levels
highest rates (inc quickest) in china, india, USA
can cause blindness, kidney disease, CHD risk inc (67% die from CHD, vs ~30% for av person)
- amputation possible
Diabetes stats overtime (1958 to 2015)
1958: .98% of people had diabetes ~1.6 million
2015: 7.3% of people have diabetes ~23.4 million
places with greatest jump in prosperity had greatest climb as toxic food enviro inc (bc people can now afford to eat out instead of making/growing own food)
Type 1 mellitus (diabetes)
- pancreas cannot make effective insulin
- genetic disposition
- early viral infections associated: pancreatic insulin producing B cells get infected - autoimmune disorder)
- ~5% have this
- must take insulin
Type 2 mellitus
- body cells become resistant to influence of insulin
- correlated with obesity and inactivity (90% overlap)
- can be genetic, most diet tho
- early treatment - diet change and activity inc (inc sensitivity to insulin)
- eventually, pancreas will wear out and need to take insulin
- makes up 95% of diabetes cases
Glucose tolerance
measure of persons ability to remove excess blood glucose following a meal
- range of numbers from normal to mellitus
glucose tolerance test
- give glucose drink to fasted person
- take blood samples over 2-3 hours
- blood glucose will inc as its absorbed from GI
- body should respond as pancreas makes insulin
- hopefully BS spikes then drops/levels out
glucose tolerance curve of a normal person vs someone with mellitus
normal: fasted BS ~5 mmol. ~30 min after drink, jumps to 7.5mmol, then begins to drop. At 1 hour, ~6, after 2 hours back to 5 mmol
mellitus: fasted BS ~7.5 mmol. ~30 min after drink, jumps to ~12 mmol, and keeps rising. At 1 hour, ~15 mmol. After 2 hours back to ~10 mmol.
> 10 mmol, glucose starts to appear in urine (renal threshold)
Doctors are looking for what during a glucose tolerance test?
- higher fasted blood glucose level
- higher blood glucose peak attained
- highest point is later than in a normal person (delayed peak)
- blood glucose levels stay higher for longer
Diabetes symptoms
thirsty, hungry, having to pee constantly
glycemic response to foods with fibre vs refined foods
in refined CHOs, higher and quicker peak of glucose levels in blood, then drops off
with fibre, gradual peak that keeps for longer
Fructose basics
- fruit sugar
- less cariogenic than sucrose (caries cavities)
- in 1970 0% used, in 2020 33% all sugar intake
- coincides with inc in obesity and type 2 mellitus
- sweetener in cereals, ketchup, pop, syrups, candy
- most americans over 2 yrs old have >62 lbs of high fructose corn syrup (HFCS)/yr which is ~130 kcal/day
is HFCS contributing to the obesity epidemic?
- body does not stimulate insulin secretion to HFCS or enhance leptin production (full feeling, no satiety cue to stop eating)
- stimulates liver fat synthesis and boosts blood TGs (inc CHD risk)
- humans have never consumed current amnt of HFCS
- just 1 daily 16 oz bottle pop adds to 20 lb weight gain in 1 year
Sucrose basics
glucose and fructose
table sugar
isolated from sugar beet/cane
sucrose myths: blamed for… (12)
- which are true?
- dental carries (TRUE)
- glucose intolerance
- insulin resistance
- behavioural hyperactivity
- malabsorption syndromes
- kidney disease
- diabetes type 2 (CORRELATED)
- lipidemias (inc TG and LDL, dec HDL) (CORRELATED)
- CHD risk inc
- obesity (CORRELATED)
- food allergies
- carcinogenicity
Do sugars cause obesity? *facts
- low fat trend removed cals from fat and made them up with excess sugars so total cal intake had more sugar
- overall kcal/day increased in general tho
- kcal from drinks is not detected in same way as food so we won’t get full - inc cal and we still eat after that
- foods with simple sugars and refined carbos are less filling than foods rich in complexes (starch) and fibre
- refined sugars have no nutrient value other than 4 kcal/g so empty kcal
Her recommendations about sugar?
have low kcal beverage in smaller vols
select nutrient dense options over cal dense
metabolic syndrome symptoms
- abdominal obesity
- elevated fasting glucose levels inc
- TG inc
- dec HDL
- inc BP
only need 3/5 of these to be diagnosed
inc CHD risk
in last 30 years, more rates of this and has a dietary connection to inc intake of refined CHO and sugars
what can reduce chance of metabolic syndrome
eat more fruits and vegetables
less juice
inc fibre
Added sugar recommendations over the years
2005 DRI - <25% total kcal *too much: ~31 tsps
WHO - <10% total kcal ~12.5 tsps
EWCFG - make foods to dec sugar
2009 AHA - women have 25g/day ~6 tsps (<100kcal)
men have 37.5g/day ~9 tsps (~150kcal)
timmy hoe’s 430g chocolate muffin has how many tsps of added sugar?
10 tsps
Lactose basics
disaccharide of glucose and galactose
milk sugar
relative sweetness of 0.2, sucrose is 1 (aspartate is 200-300)
all infants and kids have lactase, as we get older most ppl lose ability to make lactase (intolerance)
lactase deficiency
most adults cannot break down lactose bc we can’t make lactase (gradual dec 4 yrs old to 16 yrs old)
lactose intolerance
symptoms associated with lactase deficiency
MILK SUGAR INTOLERANT
Issues with undigested lactose (i.e. why do you get a stomach ache?)
- enters SI as disaccharide, attracts lots of water (bloating)
- enters LI and bacterial enzymes ferment lactose producing water, methane and carbon dioxide (gassy)
- fermentation causes diarrhea with all extra water (not able to be absorbed by colon)
milk allergy
MILK PROTEIN causes immune response
- milk protein leaks out of SI and into blood via mucosa
- blood mounts immune response (antibodies, can lead to anaphylaxis)
Digestible carbohydrates
- simples (monos and di’s)
- oligos (raffinose, stachyose, verbascose - prebiotics, common thickener agent)
- starch (complex)
Indigestible carbohydrates
- resistant starch (legumes, oats - soft when warm, solid when cool - resist amylase ex, cooked white rice and potatoes)
- dietary fibre (soluble and insoluble) *PLANT materials
soluble fibre
- inside of fruit
apples, pears, any pulp, oatmeal, psyllium, citric anything
pectin and gums
insoluble fibre
- outside (skin) of fruit/veg, psyllium
cellulose, hemicellulose, lignin (strawberry seeds)
what does soluble fibre do inside the colon
viscous - gel forming
- digesta enters LI and bacteria ferment it (make methane, hydrogen gas) into acetate, propionate and butyrate
Acetate
- 2C
- enter HPS via portal vein
- offers minimal cal
Propionate
- 3C
- goes to liver by HPS and stops cholesterol synthesis