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FNDH 400 Exam 1 – 4
FNDH 400 Exam 1
- Carbohydrates are made of: Carbon, hydrogen, oxygen
- Proteins are made of: Carbon, Hydrogen, oxygen, nitrogen
- Lipids include: fatty acids, triglycerides, phospholipids
- Lipids are made of: Carbon, hydrogen, oxygen
- Macronutrients definition: Nutrients needed in large amounts
- Micronutrients definition: Nutrients needed in smaller amounts but still important
- What are the macronutrients?: Carbs, Proteins, Lipids, Water
- What are the micronutrients?: Vitamins and minerals
- What is a vitamin: COMPOUNDS essential for normal physiological processes
- What is a mineral: ELEMENTS essential for normal physiological processes
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in the body
- What is a calorie?: Energy needed to raise 1 g of water 1 degree C
- How are kcals determined: A food is put into a bomb calorimeter and the
energy output is determined by the heat produced - Kcal/g of the nutrients: Carbs: 4
Proteins: 4
Lipids: 9
Vitamins, Minerals, Water: 0
Alcohol: 7 (but not a nutrient) - Phytochemical definition: Compounds found in plants that are believed to
provide healthy benefits beyond the traditional nutrients - Phytochemical found in tomatoes that is thought to decrease cancer risk
(esp. prostate): Lycopene - Diets rich in and have been shown with a decreased rate in
chronic diseases.: fruits and vegetables - Zoochemicals: Compounds found in animals that are believed to provide
healthy benefits beyond the traditional nutrients
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- Compounds that are both phyto and zoochemicals: Lutein and Zeaxanthin
- yellow carotenoids found in kale, spinach, and corn. or found in egg yolk
- Functional food defintion: A food, or food ingredient, that may provide a
health benefit beyond the traditional nutrients it contains
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- 3 types of studies: Cross-sectional: Present
Case-control: Past
Prospective cohort: future - Cross-sectional study: Compare different populations at the same point in
time - Example of a cross-sectional study: French paradox. Despite consuming
same amount of cholesterol/saturated fat france had 5x lower death rate from
coronary heart disease. Led to research into resveratol (red wine) - Ecologic fallacy: Believing that members of the group have characteristcs,
which as individuals they do not - Case control study: Look at a group of cases vs controls
Retrospective
Often uses food frequency questionnaires - Prospective Cohort study: Initial information on a group collected (food frequency questionnaire) and then group is followed over time to quantify health
- Scientific method:
get pdf at ;https://learnexams.com/search/study?query=
what digestive enzymes are released in the mouth?
- salivary amylase
- lingual lipase
- lysozyme
salivary amylase?
- released in the mouth
- cleaves 1, 4-glycosidic bonds (carbohydrate molecules)
lingual lipase
- released in the mouth
- more active in the stomach where it cleaves short-chain fatty acids in the sn-3 position of triglycerides
- plays a small role in adults
- may be more important to infants to help break down triglycerides in the breast milk
lysozyme?
non digestive enzyme that breaks down bacteria cell walls to prevent a possible infection
peristalsis?
wavelike constant movement that is caused by muscular contractions to move food from the stomach through the pylorus into the duodenum & throughout the digestive system
heartburn?
burning sensation (acid reflux) in the esophagus due to the very acidic gastric juices from the stomach moving back up b/c the lower esophageal sphincter is leaking
what are the different secretions from the gastric pits? what digestive processes occurring in the stomach?
- Gastrin stimulates the release of pepsinogen and hydrochloric acid
- Hydrochloric acid denatures salivary amylase, proteins, and activates pepsinogen to pepsin
- Gastric lipase is also released by gastrin stimulation, cleaving sn-3 fatty acids
- The stomach is converting food to chyme
- In the process of gastric emptying, the chyme exits the stomach through the pyloric sphincter
- mucus helps protect the lining of the stomach from the acids
villi?
finger like projections in the small intestine
enterocytes?
an absorptive cell w/ a brush border (apical) membrane that form a glycoprotein-carbohydrate layer
microvilli?
microvilli on the enterocytes increase the absorptive area by 600 times
lumen?
the cavity “outside of the body” that chyme moves through
what are the digestion accessory organs?
- liver
- gallbladder
- salivary glands
- pancreas
liver?
organ of digestion & excretion that produces bile for lipid digestion
- hepatocytes = primary functioning liver cells
- hepatic stellate cells = lipid storing cells
gallbladder?
stores and concentrates bile from the liver & secretes it into the duodenum as needed for digestion
salivary glands?
produce saliva which helps w/ the process of swallowing & chewing food
- enzyme amylase makes it easier for the stomach to break down starch
pancreas?
secretes pancreatic juice (bicarbonate & digestive enzymes) into the duodenum
- dual endocrine & exocrine gland near the stomach that secretes insulin & glucagon, which regulate blood glucose, as well as enzymes that aid in digestion & break down sugars, fats, starches
contents of pancreatic juice?
- bicarbonate w/ a pH of 8 that helps to neutralize the chyme that comes in extremely acidic at a pH of 1
- digestive enzymes
purpose of pancreatic juice?
neutralizing agent & provides necessary enzymes:
- pancreatic alpha amylase
- proteases
- pancreatic lipase & procolipase (not an enzyme)
- phospholipase A2 & cholesterol esterase
purpose of bile?
- break down fats
- has an emulsification action acting against triglycerides/fats
- fat is hydrophobic & is entering a watery environment
- produced in the liver, stored in the gallbladder
what enzymes are active in the small intestine?
- pancreatic alpha-amylase
- brush border disaccharide
- pancreatic lipase
- colipase
- phospholipase A2
- cholesterol esterase
- proteases
- brush border peptide
what products left for uptake into enterocytes (after active enzymes)?
carbohydrates, protein, triglycerides
carbohydrates? (into enterocytes)
pancreatic-alpha amylase breaks the 1-4 alpha glycosidic bonds in polysaccharides
- disaccharide enzymes (lactase, sucrase, maltase) are ectoenzymes on the brush of enterocytes that cleaves disaccharides into monosaccharides so they can be absorbed
- aplha-dextrinase, also on the brush border, cleaves alpha 1-6 glycosidic bonds in dextrins
- end product –> glucose, fructose, galactose are ready for absorption into enterocyte
protein? (into enterocytes?
proteases are activated in a cascade
- end products –> peptides (tripeptides & dipeptides) and amino acids
- peptidases on the brush border cleave peptides to individual amino acids or small peptides
probiotics?
- live microorganism that is consumed & colonizes in the body
- consumption of bacteria itself
prebiotic?
- nondigestible food component that selectiely stimulates growth of beneficial intestinal bacteria
- typically fermented bacteria
- ex: insulin, other fructose-containing oligosaccharides, polysaccharides, resistant starch
- due to oligosaccharide composition (beta bonds) it survives digestion in the small intestine so it can be fermented in the colon
synbiotic?
- contains both probiotics & prebiotics
- believed to have a synergistic effect by inhibiting the growth of pathogenic bacteria & enhancing the growth of beneficial organisms
postbiotics?
metabolites secreted by microbiota
what is the gut microbiota? how does the concentration vary throughout the GI tract?
microbiota = microorganisms found in the GI tract
- measured in colony forming units (CFU)
& is highest in the colon - concentration increases as you move down the GI tract
microorganisms that inhabit the GI tract?
- flora, microflora, microbiota
- density of the microorganisms increases as you move down the GI tract
what are macronutrients
-nutrients needed in larger amounts
-carbohydrates, protein, lipid (fats), water
what are micronutrients
-nutrients needed in smaller amounts (but still important)
-vitamins & minerals
carbohydrates?
-made of carbon, hydrogen, & oxygen
-example: sucrose (table sugar)
proteins?
-made up of carbon, hydrogen, oxygen, & contain nitrogen
lipids?
-consist of fatty acids, triglycerides, phospholipids, & sterols (cholesterol)
-composed of carbon, hydrogen, & oxygen
water?
-made up of oxygen & hydrogen
-only macronutrient that does not provide energy
vitamins?
organic compounds that are essential for normal physiologic processes in the body
minerals?
elements
(think periodic table) that are essential for normal physiological processes in the body
understand what a “calorie,” as used by the public, represents
-kilocalorie is commonly referred to as “calorie”
-kilocalorie = amount of energy needed to raise 1 kilogram of water 1 degree celsius
- a food’s kilocalories are determined by putting the food into a bomb calorimeter and determine the energy output (energy = heat produced)
know what nutrients provide energy & how much
-protein = 4 kcal/g
-carbs = 4 kcal/g
-protein = 9 kcal/g
-alcohol = 7 kcal/g (not considered a nutrient, but still provides energy)
what are functional foods?
-generally a food or ingredient that may provide a health benefit beyond the traditional nutrients (macro/micronutrients) it contains
-often a rich source of a phytochemical or zoochemical, or contain more of a certain nutrient than a normal food
what are phytochemicals?
-compounds in plants (phyto) that are believed to provide health benefits beyond the traditional nutrients
-ex: lycopene in tomatoes)
what are zoochemicals?
-compounds in animals that are believed to provide health benefits beyond the traditional nutrients that food contains
-ex: lutein & zeaxanthin found in egg yolks)
different forms of nutrition research
-cross sectional
-case control
-cohort
-in vitro
-in vivo
what is a cross sectional study?
-comparing different populations at the same time
-ex: comparing different countries to each other
what is a case control study?
-retrospective (looking back in time), looking at cases (diseased) vs. control (no disease) and comparing them to each other, food frequency questionnaire
-used in many types of epidemiology
what is a cohort study?
prospective (looking ahead/following as time goes on?, information is taken at the beginning of the study as a baseline and then see if they develop a disease
what is a in vitro study?
research done within cells, cells grow in an incubator
what is an in vivo study?
in living (animals/humans), often done in rats since it is unethical to do in humans
what is a clinical trial study?
what is a human intervention study?
What is statistical significance?
-represented by p values
-<0.05, but 0.05 is not statistical significant
what is interpreting research statistics? (OR, RR, HR)
1 = neutral
less than 1 = decrease risk
greater than 1 = increase risk
understand the process to publish a research article
- researchers write a paper
- researchers submit their paper to a journal
- reviewers provide recommendations to the researcher about the paper
- researchers complete revisions and editor approves paper
- paper is published
know how to rank the different forms of nutrition evidence (1-7)
- systematic literature reviews
- clinical trials
- cohort
- case control
- cross sectional
- animal studies
- in vitro
what is a systematic literature review? (why ranked 1)
are considered the highest level of nutrition research evidence because they synthesize the findings from multiple trials or studies
what is a clinical trial/human studies? (why ranked 2)
best form of primary research because their findings should be directly translatable to patients
what is an in vitro study? (why ranked last)
-lower quality than the animal study because digestion and bioavailability are not always being accounted for and it’s a simpler model -animals metabolism and physiology is different than humans
what is a simple carbohydrate?
contain either 1 or 2 sugars (monosaccharides; 1 & disaccharides; 2)
what is a complex carbohydrate?
contain 3 or more sugars (oligosaccharides; 3-10 & polysaccharides; >10)
what are types of monosaccharides? (containing 1 sugar)
glucose, fructose, galactose
what are types of disaccharides? (containing 2 sugars)
maltose, sucrose, lactose
what is galactose?
monosaccharide; rarely found alone in nature, normally found in the disaccharide lactose
what is fructose?
monosaccharide; 5 member ring structure; commonly found in fruits and used commercially in many beverages and is considered the sweetest monosaccharide
what is glucose?
monosaccharide, product of photosynthesis, major source of energy in our bodies
what is maltose?
disaccharide, 2 glucose bonded together by alpha bond, present in alcoholic beverages & barley
what is lactose?
disaccharide, glucose and galactose bonded by beta bond, different than other disaccharides because of beta bond
what is sucrose?
disaccharide, glucose and fructose, alpha bond, table sugar, only made by plants
what is the difference between high-fructose corn syrup and sucrose?
-glucose and fructose are free in HFCS, bonded together in sucrose
what is similar between high-fructose corn syrup and sucrose?
-both are similar in amount of monosaccharides (glucose & fructose) it contains
-fructose consumption is the same from sucrose & HFCS
what are sugar alcohols?
-less sweet than caloric sweeteners
-provide about half the calories of sucrose
-consuming a large amount can cause laxative effect
why are sugar alcohols a product good option for chewing gum?
advantage of sugar alcohols over sugars is that sugar alcohols are not fermented by bacteria on the tooth surface
what are the alternative sweeteners?
-aspartame
-saccharine
-neotame
-advantame
-acesulfame K
-sucralose
-stevia
-monk fruit
what is saccharine?
-bitter and sweet
-heat stable alternative sweetener
what is aspartame?
-PKU cannot eat because the lack of phenylalanine hydroxylase can lead to brain damage and mental retardation
-when heated, loses its sweet flavor
what is neotame?
-similar to aspartame, sweeter
-not a concern for those with PKU
-heat stable
what is advantame?
-similar to aspartame
-sweetest
-not a concern for those with PKU
-heat stable
what is acesulfame-K?
-not digested or absorbed, provides no energy or potassium to the body
-heat stable
what is sucralose?
-similar to sucrose except that 3 OH are replaced by Cl
-not digested
-heat stable
what is stevia?
-natural
-heat stable
what is monk fruit?
-lou han guo
-natural
-heat stable
what are the structural differences between oligosaccharides and polysaccharides?
-oligosaccharides are composed of 3-10 monosaccharides bonded together (oligo means few)
-oligosaccharides are not digested and reach the colon to be fermented = gas
-polysaccharides contain greater than 10 monosaccharides bonded together (ie. starch, glycogen, most fibers)
what is Beano and how does it work?
contains an enzyme (alpha-galactosidase) to breakdown oligosaccharides, thus preventing them from reaching the colon & being fermented to produce gas
what is starch? (polysaccharide)
-storage form of glucose in plants
-amylose & amylopectin are the two kinds of starch
-amylose is a linear polysaccharide, where are amylopectin is branched
-amylose is linear with only α 1-4 bond
-amylopectin is branched and has α 1-4 and α 1-6 bonds (branched points)
what is glycogen? (polysaccharide)
-animal storage of glucose
-branched points are α 1-6 bonds and linear bonds are α 1-4 bonds
-multiple ends are where enzymes cleave off glucose molecules
-many ends available = provides glucose much more quickly to the body than it could if it was linear
what is nonfermentable, nonviscous fiber?
-decreases constipation and decreases colon cancer
-makes stools bulkier which decreases the time it stays in the colon, reducing the amount of time the colon is exposed to carcinogens
-was considered insoluble
what is fermentable, viscous fiber?
-decreases blood cholesterol & blood glucose
-was soluble
what is the structure of amino acids?
-building blocks of protein (the base)
-made up of an amino group, a carboxylic acid, and a side group that varies between them all
-“R” group changes the structure of the chain to an amino acid
what is the structure of a protein?
-primary: linear polypeptide chain
-secondary: beta-pleated sheets or alpha-helices due to H bonding between amino acids in the same polypeptide
-tertiary: attraction between two different amino acids of secondary structures
-quaternary: globular, multiple polypeptide chains bonded together
how are proteins synthesized?
-cells make proteins through transcription & translation
-transcription = transfer of genetic instructions in DNA to mRNA
-translation = uses the mRNA formed from DNA as a transcript, mRNA is read in 3 letter codons that correspond to the anticodon on the tRNA, the proper amino acid for each anticodon is attached to the tRNA and as you move from codon to codon on the mRNA transcript you synthesize a polypeptide
what is an essential amino acid?
-cannot synthesize 9 amino acids
-need to consume in diet
-known as indispensable
what is a conditionally essential amino acid?
not usually essential but can become in special circumstances
what is a non-essential amino acid?
-can be made in our body, so we do not need to consume
what is PKU?
-has a mutation in the enzyme phenylalanine hydroxylase prevents the normal conversion of phenylalanine to tyrosine
-tyrosine is conditionally essential for people with PKU becuase it cannot be synthesized by the body
-needs to limit protein and aspartame intake
how does PKU relate to amino acids and aspartame?
-tyrosine cannot be synthesized by people with
PKU
, it becomes essential for them
-ppl w/
PKU have to avoid the alternative sweetener aspartame
, because it can be broken down to phenylalanine
what is a limiting amino acid?
-an essential amino acid is one that is not found in adequate amounts in an incomplete protein
-it is the amino acid that limits a protein from being complete
what is a complete protein?
a protein that contains adequate amounts of the 9 essential amino acids
what is an incomplete protein?
protein contains a limiting amino acid
what are complementary proteins?
-incomplete proteins with different limiting amino acids to provide adequate amounts of the essential amino acids
-they supply the amino acid(s) missing in the other protein
-do not need to be consumed at the same time or meal, met on daily basis
what is an Amino acid score?
-does not incorporate protein digestibility
-limiting essential amino acid/needs of same essential amino acid
-less than 100 indicates that at least 1 amino acid is limiting and it’s incomplete
what is PDCAAS?
-protein digestibility
-Amino acid score x digestibility
-truncated at 100
what is DIAAS?
-amino acid digestibility
-iileal digestibility: end of small intestine where amino acid uptake/absorption occurs
-3 reference patterns (age groups)
-not truncated
what is the Kwashiorkor class or protein-energy malnutrition?
-round belly, frail limbs
-have energy but inadequate protein intake
what is the Marasmus class or protein-energy malnutrition?
-dying away
-no energy, inadequate protein intake
what are differences between how lipids, fats, and oils are defined? (chemist vs. caloric)
-chemist: differentiated by their physical properties (solid, liquid at room temp)
-caloric: caloric effect (9 kcal/g = fat)
what is a trans fatty acid?
-partial hydrogenation of unsaturated fatty acids
-melting point increase
-more likely to be solid at room temperature
-more shel stable = more resistant to oxidation
what is a cis fatty acid?
-most are natural unsaturated fatty acid
-do not pack together well like trans and saturated
-melting point is lower than trans and saturated
what is the omega system?
-counts carbons from methyl end to carboxylic acid end of a compound
-mega symbol represent location of first double bond
-to know name of fatty acid, you have to know the # of carbons, how many many double bonds, & location of first double bond (counting from methyl end)
omega system example? (monounsaturated)
oleic acid- 18:1 (n-9) has 18 carbons, one double bond, and the double bond is located at the 9th carbon counting from the methyl end
- this is a monounsaturated fatty acid b/c it has one double bond & is in a cis formation.
omega system example? (saturated)
palmitic acid- 16:0. – 16 carbons counting from the methyl end & no double bonds.
what is hydrogenation?
-the addition of hydrogens to the carbon atoms of the fatty acid chain
-if unsaturated fatty acid is completely hydrogenated = converted to a saturated fatty acid
-increase melting point = solid at room temp
-increase shelf life = prevent oxidation
-increases low density lipoprotein & decreases high density lipoprotein levels
why are linoleic and alpha-linolenic acid essential?
- we cannot synthesize them- no enzyme to desaturate them (add a double bond) at the omega 6 & 3 position- they are both polyunsaturated
differences between omega-3 & omega-6 fatty acids in eicosanoid production? how does it relate to health?
- omega-3 fatty acids derived eicosanoids are considered anti-inflammatory so by replacing the more inflammatory than omega-6 fatty acid derived eicosanoids.- omega-3 & omega-6 fatty acids compete for the same enzymes, thus consuming more omega-6 than omega-3 may be more detrimental to one’s health than helpful- difference between both is primarily a result of the eicosanoids produced from them
triglycerides structure?
- glyceride backbone
- consists of 3 fatty acids
sterols structure?
consists of carbon rings, a cholesterol ester, & a fatty acid
phospholipid structure?
phosphate & choline head + glycerol neck + 2 fatty acid tails
Carbohydrates are made of
Carbon, hydrogen, oxygen
Proteins are made of
Carbon, Hydrogen, oxygen, nitrogen
Lipids include
fatty acids, triglycerides, phospholipids
Lipids are made of
Carbon, hydrogen, oxygen
Macronutrients definition
Nutrients needed in large amounts
Micronutrients definition
Nutrients needed in smaller amounts but still important
What are the macronutrients?
Carbs, Proteins, Lipids, Water
What are the micronutrients?
Vitamins and minerals
What is a vitamin
COMPOUNDS essential for normal physiological processes
What is a mineral
ELEMENTS essential for normal physiological processes in the body
What is a calorie?
Energy needed to raise 1 g of water 1 degree C
How are kcals determined
A food is put into a bomb calorimeter and the energy output is determined by the heat produced
Kcal/g of the nutrients
Carbs: 4
Proteins: 4
Lipids: 9
Vitamins, Minerals, Water: 0
Alcohol: 7 (but not a nutrient)
Phytochemical definition
Compounds found in plants that are believed to provide healthy benefits beyond the traditional nutrients
Phytochemical found in tomatoes that is thought to decrease cancer risk (esp. prostate)
Lycopene
Diets rich in __ and have been shown with a decreased rate in chronic diseases.
fruits and vegetables
Zoochemicals
Compounds found in animals that are believed to provide healthy benefits beyond the traditional nutrients
Compounds that are both phyto and zoochemicals
Lutein and Zeaxanthin – yellow carotenoids found in kale, spinach, and corn. or found in egg yolk
Functional food defintion
A food, or food ingredient, that may provide a health benefit beyond the traditional nutrients it contains
Scientific method
3 types of studies
Cross-sectional: Present
Case-control: Past
Prospective cohort: future
Cross-sectional study
Compare different populations at the same point in time
Example of a cross-sectional study
French paradox. Despite consuming same amount of cholesterol/saturated fat france had 5x lower death rate from coronary heart disease. Led to research into resveratol (red wine)
Ecologic fallacy
Believing that members of the group have characteristcs, which as individuals they do not
Case control study
Look at a group of cases vs controls
Retrospective
Often uses food frequency questionnaires
Prospective Cohort study
Initial information on a group collected (food frequency questionnaire) and then group is followed over time to quantify health outcomes of the individual
Framingham Heart Study
Started in 1948
Following residents to identify risk factors for heart disease
Nurses Health Study
Started in 1976
Every 4 years, 122k nurses are given food frequency questionnaires
Health Professionals Follow up study
Started in 1986
51K male health professionals
Every 4 years, food frequency questionnaires
From the Health Professionals Follow Up study, what was determined
Tomato sauce, tomatoes, pizza, and strawberries had decreased incidence of prostate cancer
What did the foods have in common from the Health Professionals Follow Up Study?
Tomato –> Lycopene
Strawberries –> Anthocyanins
In vitro research
Simplest form of nutrition research
Means “within glass”
Cell culture
In vivo research
Animal study
often mice and Rats
Pros/Cons of in vivo research
Pros
Can do tests that are considered unethical for humans
Knows exactly what subject eats
Expert reporting
Cons
Animal metabolism/physiology is different
Clinical trial
Scientifically controlled study using consenting people to find the safety and effectiveness of different items/regimens
Gold standard
A p-value of less than _ is used to indicate statistical significance.
Meaning that…
.05
5% of the time the results are accidental or not true
OR, RR, HR values and signficance
<1 is lowered risk with exposure
1 is no effect
1 is increased risk with exposure
Confidence interval
Estimated range that the measure is calulated to include
Often 95%
Large VI = Less confidence in value
Small CI = More confidence in value
Must not overlap 1 for OR,RR, or HR to be considered significant
American Society for Nutrition publishes which journals?
Journal of Nutrition
American Journal of Clinical Nutrition
Academy of Nutrition and Dietics publishes which journals?
Journal of the Academy of Nutrition and Dietetics
Systematic literature review; considers which type of studies
Finds conclusion based on evidence in multiple journal articles
Only considers Epidemiological studies and Clinical Trials
Epiemiolgical studies __ show causalty
Cannot. Instead just identifies relationships or associations
What is the best form of primary research?
Clinical trials/human studies
Ranking of research types, from best to worse
Systematic Literature Reviews
Clincial trials
Prospective Cohort
Case-Control
Cross-Sectional
Animal Studies/In vivo
In vitro
Order of research progression
Epidemiological
In vitro
Animal studies
Clinical trials
Beta carotene and lung cancer
Thought high dose beta-carotene would decrease lung cancer risk, but actually increased it!
Selenium, Vitamin E, Prostate Cancer
Thought it would decrease prostate cancer. Vitamin E increased cancer, Selenium increased diabetes
Secondary result
Not primary outcome the trial was designed to find
Reductionist approach
Takes a complex food and reduces it to simpler componets
Monosaccharides
Glucose
Fructose
Galactose
Disaccharides
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
What are polysaccharides? Common forms?
10 sugars
Starch (Amylose and Amylopectin)
Glycogen
Fibers (Cellulose, Gums, Pectin)
Oligosaccharides
Raffinose
Stachyose
Glucose
6-member ring
Product of photosynthesis
Major source of energy in our body
Fructose – bond appearance?
5-member ring
Commonly found in fruits
Commercially used in many beverages
Galactose
6-member ring
Not normally found in nature alone
How are disaccharides formed?
2 monosacharides and a hydration reaction
Maltose
Glucose + Glucose
Alpha bond
Malt sugar
Seldom found in foods
Alcoholic beverages and barley
Sucrose
Glucose + Fructose
Alpha Bond
Table Sugar
Only made by plants
Calories
Lactose; bond
Galactose + Glucose
Beta bond
Milk Sugar
Glycosidic
Sugar bond
Why do we need lactase?
To break the beta bond found in lactose
High fructose corn syrup ratio
42-55% Fructose
45-58% Glucose
VERY similar to sucrose
Sugar Alcohol
“Sugar replacer”
Nutritive sweeteners –> Calories
Nearly as sweet as sucrose, half the calories
Why are sugar alcohols often found in gum?
Not fermented by bacteria on the tooth surface –> No dental caries
How does sugar cause tooth decay?
Fermented by bacteria on surface of teeth
Higher acidity which leads to decay
Tagatose
Isomer of fructose
Small amount of energy (1.5kcal/g)
80% reaches large intestine to be fermented by bacteria = prebiotic-like
Structurally similar to sugar alcohol
Non-nutritive sweteners
Aspartame
Advantame
Acesulfame-Potassium (K)
Luo Han Guo Fruit Extract
Stevia
Saccharin
Sucralose
Neotame
Saccharin
If used in cooking, will develop bitter taste
Aspartame
Broken down to amino acids during digestion
provides 4 kcal/g but not significant
Can be broken down to phenylalanine
When heated, loses its sweet flavor
Neotame
Structurally identical to aspartame but has additional side group
Sweeter than aspartame
Heat-stable
Not broken down to amino acids –> No PKU trouble
Advantame
Heat stable
High acceptable daily intake
Sweetest
Newest
Acesulfame-Potassium (K)
Not digested or absorbed
No energy
Sucralose
Structurally similar to sucrose except 3 of alcohol groups are replaced by Chlorine
b/c of this Not digested
Stevia
Plant
Steviol glycosides –> sweet taste
Luo han guo fruit extracts
Chinese fruit
Mogrosides –> Sweet taste
How does our body deal with oligosaccharides
Cannot digest alpha 1-6 glycosidic bonds
Fermented by bacteria in colon –> Gas
Beano
Alpha-galactosidase breaks down oligosaccharides
How is starch used in plants
Storage form of glucose
Amylose structure
Linear polysaccharide
alpha 1-4 glycosidic bonds
Amylopectin stucture
Branched
alpha 1-6 glycosidic bonds
Which amylo is more common in starch?
Amylopectin is more common than amylose (4:1)
Glycogen is used how in animals
Storage form of glucose
Glycogen structure
Highly branched
alpha 1-6 branched bonds
alpha 1-4 linear
Advantage of glycogen highly branched structure
Multiple ends are where enzymes cleave off glucose molecules
Do we get glycogen>
No! broken down in animals after slaughter
Fiber definition
indigestible matter
Dietary fiber
Non digestible carbs and lignins that are intrinsic and intact in plants
Functional fiber
Isolated, nondigestible carbs that have beneficial physiological effects in humans
Total fiber
dietary fiber and functional
Dietary vs functional fiber
Dietary:
Intact in Plants
Carbs and lignins
Only from plants
No proven benefit
Functional fiber:
Isolated, extracted, synthesized
Only carbs
From plants or animals
Must prove benefit
Polysaccharide fiber differes from other polysaccharides in what structural way
contains beta-glycosidic bonds (as opposed to alpha glycosidic bonds)
Cannot be broken down
Good foods with nonfermentable nonviscous fiber
Whole wheat, whole-grain cereals, broccoli, and other veggies
Benefits of nonfermenable nonviscous fiber
Increase stool bulk, reduce transit time –> Lowers risk of constipation
Lower risk of colon cancer–> Less exposure to consumed carcinogens
Sources of fermentable viscous fiber
Oats, rice bran, psyllium seeds, soy, some fruits
Benefits of fermentable viscous fiber
Lowers risk of heart disease and diabetes
Slows absorption of glucose –> Prevents blood glucose from spiking after consuming carbs
Binds bile acids (cholesterol) and causes them to be excreted –> More cholesterol used to create bile acids –> Low cholesterol
Protein synthesis
DNA contains genetic code that’s used as a template to create mRNA in transcription. mRNA then moves out of the nucleus into the cytoplasam where it serves as a template for translation, where tRNAs bring in amino acids to form polypeptide
Protein structure function
Collagen – scaffolding of the body
Hormone
Compound produced in one tissue, released into circulation, then has an effect on a different organ
Proteins and Fluid balance
Proteins help maintain balance between plasma and interstitial fluid
Acid Base balance
Proteins act as buffers
How can proteins be used for energy?
Gluconeogenisis –> Forms glucose
Essential amino acids
Body cannot synthesize at all
Conditionally essential amino acids
Under normal circumstances the body can synthesize these, but are essential for individuals in certain situations (ex. PKU and the need for Tyrosine)
Non-essential
Can be made in body, do not need to consume them
PKU and diet
Phenalyenine would typically be broken down into tyrosine. Due to a mutation, it cannot be. Phen and its metabolites build up leading to brain damage and mental retardation.
Must have low protein diet and avoid aspartame because it is broken down to phen
Complete proteins
Provide adequate amounts of all nine essential amino acids
Good sources: animal proteins
Incomplete proteins
Do not contain adequate amounts of one or more essential amino acids
Often plant based proteins
How do you solve incomplete proteins?
Complementary proteins
Complementary proteins
When you pair two or more incomplete proteins with different limiting amino acids to provide adequate amounts of essential
Measures of protein quality
BV – Biological Value
PER – Protein Efficiency Ratio
AAS – Chemical/Amino Acid Score
PDCAAS – Protein Digestibility Corrected Amino Acid Score
DIAAS – Digestible Indispensable Amino Acid Score
Biological value (BV)
[(gram of nitrogen retained) / (grams of nitrogen absorbed)] x 100
Protein efficiency ratio (PER)
(grams of weight gained) / ( gains of protein consumed)
Commonly performed in growing rats
Chemical/Amino Acid Score (AAS)
(Test food limiting essential amino acid) / (needs of same amino acid score)
Protein Digestibility Corrected Amino Acid (PDCAAS)
(Amino Acid Score) x (Digestibility)
Most widely used
Was preferred by Food and Agriculture Association and WHO until recently
Score truncated at 100
Digestible Indispensable Amino Acid Score (DIAAS)
100 x (mg of digestible dietary indispensable amino acid in 1g of the dietary protein) / (mg of the same dietary indispensable amino acid in 1g of the reference protein)
New standard
Why DIAAS is better
No truncating scores
Samples from intestine instead of fecal matter
Measures digestion of individual amino acids, not just crude protein
3 reference groups instead of one
Protein deficiency is commonly called
Protein-energy malutrition
Kwashiorkor
“The disease that the first child gets when the new child comes”
Marginal energy, inadequate protein intake
Marasmus
“To waste away”
Inadequate protein and energy intake
What do lipids consist of
Triglycerides
Fatty Acids
Phospholipids
Sterols
What are considered fats?
Triglycerides, fatty acids, and phospholipids that provide 9kcal.g
Oil according to chemist vs nutrition
Chemist: Oil b/c solid at room temp
Nutrition: Fat b/c 9kcal/g
Difference of fatty acids
Carbon chain length
Saturation/Unsaturation
Double bond configurations
Fatty acid chain length and classification
Short: <6 Medium: 6-10 Long >12
Most fatty acids contain somewhere between _ carbons with numbers more common than __.
4-24 carbons
Even more common than odd
Carbon chain length and melting points
Longer chain, higher melting point
What does a unsaturated fatty acid contain?
Double bond
Which is the more natural double bond formation is unsaturated fatty acids?
cis
Difference between cis and trans/sat fat
Cis do not pack together as well
Cis have lower melting point
Source of trans fat in our diets
Hydrogenation (addition of a hydrogen)
Stick-margarine
Reasons for hydrogenation
More solid texture
More shelf stable (double bonds in ufa are susceptible to oxidation)
Partial hyrdrogenation
Cis –> Trans
- Saturated fats
Which is worse trans or saturated fat? Why?
Trans, alters biomarkers for cardiovascular disease
Trans: Increase LDL and lowers HDL
Sat: increases LDL, doesn’t change HDL
Three naming systems for fatty acids
Delta
Omega
Common
What do you need to know for delta?
Number of carbons
Number of double bonds
Number of carbons from carboxylic acid end to first carbon in double bond
How to name delta
Carbon number: Double bonds ^double bond location from carboxylic end
10:1 triangle^7
Need to know to name with omega
Number of carbons
Number of double bonds
Number of carbons from methyl end to first carbon in double bond
10:1 n-3
Linoleic acid
omega 6
essential
can be elongated by elongase enzymes for eicosanoid production
a-Linolenic Acid
omega-3
essential
can be elongated by elongase enzymes for eicosanoid production
Source of omega-6
Corn, walnut, soybean
Source of omega-3
Flax seed
Source of mufa
Canola and olive oil
Source of saturated fatty acids
Lard, palm oil, butter, coconut oil
Why are linoleic and alpha linoleic acid essential?
Why are other fatty acids not?
We don’t have an enzyme capable of adding a double bond beyond the omega-9 carbon (can’t add omega 3 and omega 6 bonds)
Other fatty acids are not essential because we have enzymes that can take them, elongate them (add 2 carbons) and then further desaturate them (add double bonds) to other omega-6 and omega-3 fatty acids.
Eicosanoids
Biologically active in the body, act locally in the tissue they are producing
4 classes of eicosanoids
Prostaglandins
Prostacyclins
Thromboxanes
Leukotrienes
What is the cause of the difference in effects of omega 3 and omega 6?
Result of the eicosanoids produced from them
Health effects of omega 6 vs omega 3
omega 3 are considered anti-inflamatory when they replace omega-6
Example of eicosanoids
Asprin, inhibits Cox-1 and Cox-2
What is the most effective way to get long chain fatty acids into our body? why?
Dietary. A-la conversion to EPA and DHA is very limited
Essential fatty acid deprivation
Rare
Symptoms:
Growth retardation
Reproductive problems
Skin lesions
Neurological and visual problems
Triglycerides
Most common lipid in our body and in food we consumed
How fatty acids are found in nature
Triglyceride functions
Provide energy
Primary form of energy storage in the body
Insulate and protect
Aid in the absorption and transport of fat-soluble vitamins
How is a triglyceride formed?
Dehydration reaction between a glycerol and three fatty acids
Esterification
Fatty acid added to glycerol backbone
Structure of triglyceride
Best known phospholipid
Lecithin
Functions of phospholipids
Key component of cell lipid bilayer
Emulsification
Are phospholipids essential?
No
Sterol sturcture
Carbon rings
How is cholesterol found in foods?
Found as a cholesterol ester (fatty acid attached)
Only in foods of animal origin
Is cholesterol essential>
no
Organs in the GI tract
Mouth, esophagus, stomach, small intestine, large intestines, rectum, and anus
Digestion accessory organs
Salivary glands, pancreas, gallbladder, and liver
Enzymes in mouth
Salivary amylase
Lingual lipase (only mainly in infants)
Stomach Enzymes
Pepsin
Gastric lipase
Small intestine enzymes
Pancreatic alpha-amylase
Pancreatic lipase
Colipase
proteases
Brush border disaccharides
brush border peptidases
phospholipase-a2
cholesterol esterase
Mechanical and Chemical digestion in mouth
M – Mastication
C – Salivary amylase (minor) and lysozyme
Lingual lipase realeased, but not active
how does salivary amylase work
Cleaves alpha 1-4 glycosidic bonds in the starch molecules, amylose, and amylopectin
Salivary amylase cannot…
Cleave alpha 1-6 glycosidic bonds
Lysozyme function
Break down bacterial cell walls to prevent infection
Lingual lipase
Most active in stomach
Cleaves short chain fatty acids in the sn-3 position
Most important for infants to break down breast milk
Esophageal Sphincter
Digestion in mouth
C: Salivary amylase cleaves 1,4-glycosidic bonds (minor)
L: Release of lingual lipase
P: None
Surface of Stomach
Mucosa covered in gastric pits
Gastric Lipase
Cleaves sn-3 position of triglycerides to produce 1,2-diglyceride and a free fatty acid
Responsible for 20% of triglyceride digestion
Action of gastric secretions in the stomach (cells)
Neck cells –> create mucus to protect lining
Parietal Cells –> HCL: inactivates salivary amylase, lowers pH of gastric juice, stimulates pepsinogen to become pepsin, denatures proteins
Chief Cells –> secrete pepsinogen and gastric lipase
G Cells –> creates gastrin to stimulate chief and parietal cells
How does pepsin work
Cleaves proteins to peptides
Pyloric sphincter
Chyme from stomach to small instestine
Digestion in stomach
Protein: Pepsin
Fat: Gastric lipase –> Triglycerides
Lining of the small intestine
Villi line lumen
Enterocytes lie villi
Microvilli line enterocytes (Brush border)
Glycocalyx line microvili
Secretin
Respons to acid in S.I.
Secretes bicarbonate
Stimulate bile to flow from liver to gallbladder
CCK
Responds to fat
Secretes digestive enzymes
Contracts gall bladder –> Bile into duodenum
Pancreas cell functions (ABA)
Alpha cell –> Glucagon
Beta cell –> Insulin
Acinar cell –> Pancreatic juice
Enzymes in pancreatic juice
Pancreatic alpha-amylase
Protease
Pancreatic Lipase and Procolipase
Phospholipase A2
Cholesterol Esterase
Liver significance
Largest internal and most metabolically active organ in the body
Primary Liver cells
Hepatocytes – carry out liver functions
Hepatic stellate – fat storing
Bile consists of
Bile acids
Cholesterol
Phospholipids
Pigments – billrubin and billyerdin
Bile acids are synthesized from..
Cholesterol
Primary bile acids
Chenodeoxycholic acid
Cholic acid
found as salts, end with (-ate)
Bile acid structure
hydrophobic and hyrdrophillic
Fat needs to cross watery small intestine to get to the enterocyte
Gallbladder function
Store and concentrate bile made by the liver
Bile transported to duodenum through common bile duct
Triglyceride droplets formed
Importance of bile
Fat is hydrophobic and the environment of the small intestine is watery, the hydrophillic head and hydrophobic tail is a great binder
Triglyceride droplet function
Increase the surface area that is accessible for triglyceride digestion enzymes
Where is the primary carb digestion?
Small intestine
Pancreatic alpha-amylase function in small intestine
Cleaves alpha 1,4-glycosidic bonds of carbs reducing them to glucose, maltose, maltriose, and dextrins (oligosaccarides containing 1 or more alpha 1,6-glycosidic bonds)
Unable to cleave alpha 1,6-glycosidic bonds (cleaved in alpha-dextrinase on brush border)
Starch Activity on surface of enterocyte
Pancreatic amylase products + Sucrose and lactose move to surface. Then disaccharide enzyemes cleave bonds forming monosaccharides
Brush border enzyme alpha dextrinase cleaves alpha 1,6-glycosidic bonds in dectrins, esp. branch point in amylopectine
Final products: Glucose, fructose, galactose
Major site of protein digestion
Small intestine
Where do proteases orginate?
Pancreas secretes as zymogens into the duodenum where they mus be activated before they can cleave peptide bonds
Protease/colipase activation cascase
Enteropepidase from brush border converts trypsinogen to trypsin –> activates all proteases including itself and colipase (fat digestion)
Do all proteins need to be cleaved down to amino acids to be absorbed in the enterocyte?
No. Small peptides such as di and tripeptides can be taken up
Major site for lipid digestion?
Small intestine
Digestion of triglycerides in small intestine
Pancreas secretes pancreatic lipase into the duodenum
Cleaces sn-1 and sn-3 fatty acids resulting in two fatty acids and a 2-monoglyceride
Colipase function
Anchor point helping lipase attach to triglyceride droplet
Phospholipase A2
In small intestine
Cleaves c-2 fatty acid of lecithin, producing lysolecithin and a free fatty acid
Cholesterol Ester digestion in small intestine
Fatty acid cleaved by cholesterol esterase –> cholesterol and a free fatty acid
Reason for mixed micelles
2-monoglycerides and fatty acids from pancreatic lipase digestion forms micelles. BUT not strong water soluble enough to cross the unstirred water layer to get to the brush border.
What makes up a mixed micelle
Cholesterol
Bile Acids
Lysolecithin
2-monoglycerides
Fatty acids
Final prodcuts for enterocyte
Lipids:
Lysolecithin
2-monoglyceride
Fatty Acid
Cholesterol
Protein:
Peptides
Amino acids
Carbs:
Glucose
Galactose
Fructose
Water
Ileocecal valve
Sphincter between ileum and large instestine
Large intestine Anatomy
Cecum
Ascending column
Descending column
Sigmoid column
Rectum
Anus
Large intestine main function
Absorbing remaining water and electrolytes (sodium, potassium, chloride)
Form and excrete feces
Contain microorganisms
Microbiota concentration in large intestine
The colon has the highest concentration of microbiota, with the concentration decreasing as you go up the small intestine until the stomach.
Bile acid action in large intestine
Bile acids fermented to form secondary bile acids, approx 20% of total bile acids in body
Fermentable fibers in large intestine
Can be used to form short chain fatty acids that can then be absorbed and use by the body
Nonfermentable fiber in the large intestine
Not altered and will be a component in feces
Prebiotic
Nondigestible food component that selectively stimulates growth of the beneficial bacteria
eg- insulin, fructo-oligosaccharides
Probiotic
Live microorganisms consume
Increases beneficial bacteria
eg – DanActive, Activia
Are pro or prebiotics better for you?
Both are. Have same ratio increase in beneficial bacteria
Special quality of a pro/prebiotic
Needs to be able to survive digestion
eg- beta bonds or oligosaccharides, resistant starch