Nutrition midterm-2

Module- 4 4- Carbohydrates and fibre

What is a carbohydrate (CHO)?

Contains C, H, and O, but in the same proportion as water (H2O)

What are the two types of CHO?

• simple (mono and disaccharides)

• complex

All CHO are made up of sugars called…

monosaccharides

do sugars go into the blood or the lymph?

blood, the only thing that goes into the lymph are the longer chain f.a

3 examples of monosaccharides? and how many carbon do they each have?

glucose, galactose, fructose

6 carbons each

Each monosaccharide chemically contains…

6 carbon, 12 hydrogen, and 6 oxygen atoms, but just arranged differently

Glucose (def)

A monosaccharide that is the primary form of carbohydrate used to provide energy in the body. It is the sugar referred to as blood sugar

What is special about the monosaccharide (sugar) fructose?

it is 5-sided (instead of 6-sided like the others)

Disaccharides; 3 of them

• Maltose

• Sucrose

• Lactose

What process is used to break down disaccharides

hydrolysis (using water to break things apart)

• H2O “breaksdown” the sugar

What are the disaccharides Maltose, sucrose, and lactose comprised of?

Maltose= 2Glucose

Sucrose= Glu+Fru

Lactose= Glu+Gal

sucrose is commonly known as…

table sugar or white sugar

lactose is commonly known as…

milk sugar

maltose is made when…

starch breaks down

What digestive enzymes breaks down maltose, sucrose, and lactose?

Maltase, sucrase, and lactase

What process is used to create disaccharides?

Condensation, OH and H group comes together and the product are a disaccharide and water, however we cannot do this process only plants

Oligosaccharides

• 3-10 monosaccharides

• also known as prebiotics- food for healthy bacteria (Inulin and soluble fibre are great for feeding healthy bacteria)

• some are formed in the gut during the break down of polysaccharides

• some are found naturally in foods (legumes, bananas, chickery…). they are not digestible, they go to the colon and are broken down by the intestinal microflora

• promote gastro intestinal health (GI), that is why it is recommended that you feed your baby breast milk

Polysaccharides

“poly”

hundreds-thousands of monosaccharides

What is a complex CHO?

Starch

Polysaccharide; glycogen

• the storage form of carbohydrate in animals

• highly branched chains of glucose allows it to broken down easily when glucose is needed

• stored in muscles and liver to feed body when sleeping

• made of glucose

Polysaccharide; starch

• the storage form of carbohydrate in plants

• stored in plant’s roots

• Complex CHO

• made of glucose

• made up of two types of molecules; amylose, amylopectin

Polysaccharide; fibre

• can’t be broken down (can’t be digested)

• 2 types of fibre; soluble and insoluble

• soluble- dissolves in water or absorbs water to form viscous solutions and can be broken down by bacteria in the large intestine (pectins, gums, and some hemicelluloses)

• insoluble- for the most part does not dissolve in water and cannot be broken down by bacteria in the large intestine (cellulose, some hemicelluloses, and lignin)

• made of glucose but the bonds are different

Refined

Refers to foods that have undergone processes that change or remove various components of the original food

DRI/AMDR for carbohydrate

45-65% of kcal

fibre should be ___g/1000 kcal

14g of fibre

Carb; foods that contains starch; Vegetables

potato, corn, green beans, green peas (‘green’ because they are fresh, if you let them dry out they would be legumes, and therefore be put in the meat+alt category

Carb; foods that contains starch+ sugars; Fruit

starch- banana

sugars- all fruit

Carb; foods that contains starch; grain products

“all”- contains barn, germ

Carb; foods that contains starch; Meat+ alt

meat- non because the glycogen is gone by the time we eat it

alternatives- nuts/seeds, legumes

Carb; foods that contains starch; milk+alt

milk- lactose

alternatives- soy beverage (cane sugar, oligosaccharides)

CHO diets around the world; Africa

80% of kcal, because of a root food called Cassava

CHO diets around the world; Caribbean

65% of kcal

CHO diets around the world; North America

53% of kcal

• right range but not the right types

• since 1900 in N.A, CHO intake reduced 25-30% and moved to ^ in refined CHO+ sugars (white flour), ^protein (animal), ^fat

CHO digestion; in the mouth

some starch are broken down by salivary amylase (enzyme) into maltose

What happens if you let a soda cracker sit in your mouth?

you will detect a sweet taste because of the salivary amylase breaking down the starch into maltose

CHO digestion; in the stomach

• no digestion happens in the stomach

• HCl acid denatures(inactivates) salivary amylase

CHO digestion; in the small intestine

• most starch digestion+breakdown of disaccharides occurs

• the break down of starch is done by pancreatic amylase (enzyme) into maltose and then by maltase into 2 glucose

• enzymes attach to the intestinal vili, here di and oligo are broken down into monosaccharides

CHO digestion; in the large intestine

• fibre and other indigestible carbohydrates are partially broken down by bacteria

• they form short chain f.a and gas, and some is excreted in feces

Monosaccharides metabolism; in the liver; glucose

• fructose and galactose gets turned into glucose

• meets the kcal needs of the liver

• stored in liver as liver glycogen

• makes some non-essential amino acids

• converts excess glucose to fat→ VLDL→ stored

• releases glu into blood

every body cell can use _______ as a fuel source

glucose

Monosaccharides metabolism; in the bloodstream

• kcal (energy) for all body cells (red blood cells, central nervous system/brain→ only prefer glucose)

• muscle glycogen storage→ selfish, only uses it for themselves

Glucose; basic facts

1. found only in very small amounts in plant foods (fruit)

2. Needs to be provided in the diet ideally as a fibre-rich carbohydrate source

insulin is produced by the …

pancreas

Insulin is a …

anabolic hormone “build tissue”- it tells the body to store and make things while meals are good

what does insulin do?

• facilitates ”escorts” uptake of blood glucose into cells (glucose needs an escort in order to go into body cells)

• following a meal, blood glucose levels return to “normal” (basal value)

what does insulin tell the body to do?

• make+ store liver (+muscle) glycogen

• allows the use of glucose by cells

• tells the body to store the rest in case

when you feel a hunger pang→blood glucose dropping, (body needs kcals) what does your body do?

• insulin secretion decreases and glucogon from the pancreas gets released. Glucogon mobilises liver gylcogen (that was being stored) to be broken down into glucose and released into the blood. And as a result blood glucose level return/ rise to normal

diabetes mellitus

“honey sweet”

• they found glucose in the urine

Type 1 diabetes: what percent of population? What happens? develops when? how is it determined and what do they think it is caused by?

• 5% of population

• pancreatic release of insulin fails (you can’t put glucose away, so you have to take insulin in order to do that)

• develops in teen years or early 20s

• genetically determined

• they think it caused by early viral infections→ autoimmunity (antibodies to yourself)

Type 2 diabetes: what percent of population? What happens? develops when? how is it determined

• 95% of population

• body tissues don’t listen to insulin, they resist insulin (insulin resistance)

• so when the insulin escorts the glucose the receiving body cell doesn’t see the insulin

• the pancreas believes that it didn’t release enough insulin so it releases more, therefore glucose and insulin rises (hyperinsulinemia)

• connected to overweight and lack of exercise

• after many years of type-2 diabetes the person would have to take insulin because the pancreas is exhausted

What is the drug that is given to diabetics to promote insulin sensitivity

metformin

what is glucose tolerance?

a measure of a persons ability to remove excess blood glucose following a meal

what is the range of glucose tolerance of a normal individual?

4.5-5.5 mM

what are the ranges of glucose tolerance

from normal individual (4.5-5.5mM) to→ a person with type 2 diabetes

if it is increasing from left to right then that is increasing glucose Intolerance

what is a glucose tolerance test

• give glucose drink

• take blood samples periodically over 2-3 hrs

  blood glucose increases as glu is absorbed from GI tract

  blood (pancreas) respond by making insulin

• measure every 30min

what would a “normal” glucose tolerance curve look like?

After the glucose drink, glucose levels would hit a peak and start to go down, it would go below ‘normal’ before it corrects itself and goes back to normal wall within about 2 hours

• it never touches the ‘renal threshold’ (10mM)

what would a ‘uncontrolled’ glucose tolerance curve look like?

an uncontrolled glucose tolerance curve will start above ‘normal’, like 7.5mM. there will be a delayed peak and there will be glucose in the system for longer. The peak goes above the ‘renal threshold’ for a long period of time. Finally the glucose level goes back to where it started, all within 3-4 hours

Glycemic response

“blood glucose response following eating certain foods”

e.g., whole grain bread, legumes takes longer to digest fibre, therefore they have a low Glycemic index

what kinds of foods contain fructose? and what other stuff does it have?

honey- just CHO

fruits- high in fibre, vitamins/minerals, and low in kcal

HFCS- high fructose corn syrup

if you have ‘diabetes’ during pregnancy, but after it goes away what is it called? and also what are you now at risk for?

gestational diabetes, at risk of developing type 2 diabetes

what complications are there with type 2 diabetes?

stroke, kidney failure, heart attack, blindness, and amputation

fructose; HFCS

• Cariogenic (cavity causing)

• liquid sweetener

• made from corn

• 55% fructose

• found in almost all condiments

• less$ then sucrose (table sugar)

• risen from 0% of sugar intake to 1000% of all sugar intake (1970-now)

• average american around 62lbs/year

• 130 kcal/day

what do they think that high fructose corn syrup is contributing to?

obesity

why do they think HFCS is contributing to the obesity epidemic?

the body can use fructose differently than other sugar:

• does not stimulate insulin secretion, or enhance leptin production→”you are full” (lowers satiety cues)

• stimulates liver fat synthesis+ boost TG (VLDL)→ CHD

• may promote high blood pressure which leads to risk of CHD

  Humans never consumed anything close to current fructose intake: body cannot handle large amounts

  Just 1 daily 16-oz (2 cups/500mL) bottle pop= 200kcal can add up to 20lb weight gain in 1 year

Disaccharides: Sucrose; facts

• Glu+Fru

• table sugar isolated/purified from sugar beet or sugar cane

• both crops yield more kcal/acre than any other crop

• the only real evidence of sugar is that it is cavity causing

do sugars cause obesity?

1. trend with ‘low fat’ foods, they made up the difference in carb (flour, sugar)

2. form of carbs affects satiety, liquid form of kcal is not detected as well as food forms. Foods with simple sugars and refined carb are less filling than fibre-rich carb foods

3. sugars have no nutritional value (vitamins+minerals) other than 4kcal/g

do sugars cause heart disease?

what causes obesity?

overeating anything causes obesity

metabolic syndrome; constitutes 5 features

• abdominal obesity

• increase fasting glucose (insulin resistance)

• increase TG in blood

• decrease HDL

• increase blood pressure

  if you have three or more then you will be diagnosed with metabolic syndrome

what is the dietary connection to metabolic syndrome? and what should you eat instead?

• sugars+refined carbs (carbs that have the fibre taken away)

• you should instead eat high fibre carb sources, intact V+F, and lower juice intake

what is the recommended amount of added sugar per day for women? for men?

women- 6tsp of added sugar/day

men- 9tspof added sugar/day

lactose; relative sweetness value

0.2, compared to sucrose=1

when does lactase deficiency start?

ages 3-16

of which descent maintain the ability to make lactase?

Northern Europe

consequences of undigested lactose:

• lactose doesn’t get broken down in the GI tract because of the lack of lactase, it attracts H20 which causes bloating+cramps. When it arrives at the colon it gets fermented by the bacterial enzymes that break it down, the products are gas (H2, CO2, and CH4) and diarrhea because the water could not be reabsorbed

what is a milk allergy?

an exaggerated immune response to a protein in food

• when the milk protein is consumed, in the GI tract the milk protein gets broken down into chunks, some of the chunks get into the bloodstream. An immune response will happen and will produce antibodies against it resulting in anaphylaxis

fortified

stuff added that were not really there

what is dietary fibre?

indigestible plant material

what is the distribution of soluble to insoluble when eating plants

1/3 sol: 2/3 insoluble (we get both in our omnivorous diet)

what are some examples of soluble fibres? what are some food examples?

gums, pectin, agar, carragecnin

food sources- oatmeal (oatbran: Beta-glucan), insides of legumes+fruit

what are some examples of insoluble fibres? what are some food examples?

cellulose, hemicellulose, lignin (strawberry seeds)

food sources- outside (skin/peel) of legumes, V+F (like those strings of celery)

transit time

time it takes from eating→elimination

• depends on how much fibre is in the diet

What does fibre do in the colon?; soluble fibre

• slows the movement of digesta (what remains of your meal) through GI tract

  From the small intestine into the colon:

• ‘digesta’ comes into the colon the soluble fibre is now in a gel form because it mixed with water. the bacteria in the colon will go to town to ferment because the soluble fibre makes the digesta accessible. from the fermentation the products are: gases (H2, CH4) and short chain f.a: 2:0-acetate which will be absorbed, 3:0-propionate absorbed, and goes to liver and reduces liver chol. synthesis. 4:0 butyrate, preferred energy source by the colon

What does fibre do in the colon?; insoluble fibre

• increases/speeds up the movement of digesta thru GI tract

• very densely packed interwoven structure

• bacteria has a hard time accessing it , so there is less fermentation happening, therefore you will have a greater fecal bulk

what does fibre do for the colon

soluble and insoluble fibre in the colon adds bulk and absorbs water. This increases stool weight, speeds transit, and makes the feces larger and softer

what kind of condition could happen if you have a low fibre (specifically insoluble) intake

a condition called Diverticulosis

• there is too much pressure in the colon causes weak spots that bulge out

what is the net effect of eating fibre?

because 1/3 sol and 2/3 insoluble, fibre increses the movement of digesta thru GI tract

parts of a whole grain (wheat, rye, barley, rice)

Bran- outer layer

Aleurone layer- just under the bran layer (B--vit, iron)

Germ- PUFAs/MUFAs, vit E, Fe, B vit

Endosperm- starch and protein

how does fibre help prevent colorectal cancer? soluble and insoluble

Soluble fibre

• short chain f.a acids (4:0)←preffered energy source of colon cells

• low pH (acidity) favourable environment

• stimulate growth of healthy microbiome

• results in lower levels of NH3 (ammonia)

  Insoluble

• because of its bulking effect, dilution of colonic contents (less of the bad stuff gets into contact with the cell walls)

• Provides a surface for adsorption (sticking to)(so the nasties will come out)

• reduces intestinal transit time(removing waste products on a regular basis)

• Altered bile acid metabolism(bile acids have the potential of being acted upon by pathogenic bacteria which turns them into secondary bile acids which are cancer promoters, but insoluble fibre will block the reaction)

fibre; blood cholesterol: which fibre lowers Total chol. +LDL

Soluble fibre

how does _______ fibre lower blood cholersterol?

• soluble

  1. soluble fibre binds onto bile acids, which prevent bile acid absorption

  2. Soluble fibre is readily fermented into 3:0 propionate which lowers liver chol synthesis

from the short chain f.a that are produced after fermentation in the colon from soluble fibre, what are they each associated with?

2:0 Acetate→ just gets absorbed

3:0 Propionate→ lowers liver chol synthesis

4:0 Butyrate→preferred energy source of the colon cells

Panacea

a cure all for anything

e.g., protein for weightl oss or weight gain

AI for fibre

14g fibre/1000kcal