Nutrition Mid Term Study Guide

what is a nutrient?

what is a nutrient?

Chemical substances in foods that are a source of energy, structural materials, and regulating agents. Support growth, tissue maintenance, and repair, and reduce disease risks

Inorganic Nutrients

Do NOT contain carbon. Ex: minerals and water. Simple structure: each mineral is a chemical element (e.g. calcium); water is H + O.

Organic Nutrients

Contain carbon (essential component of all living organisms). Ex: Carbohydrates, lipids (fats), proteins, vitamins. More complex structure.

What are the 6 classes of nutrients?

Carbohydrates, Lipids, Proteins, Vitamins, Minerals, & Water

What is a macronutrient?

Carbohydrates, lipids, proteins

• Required in relatively large amounts

• “Energy-yielding” (have kcalories)

What is a micronutrient?

Vitamins and minerals

• Required only in small amounts

• Do NOT have kcalories

Energy-Yielding Nutrients

Energy from food = kilocalories. Carbohydrates (4 kcals), Protein (4 kcals), Fat (9 kcals), Alcohol (7 kcals), & Sugar Alternatives (2 kcals). When bonds between nutrient’s atoms break → energy is released. Excess energy=fat storage.

Non-energy yielding

Vitamins, minerals, and water

Carbohydrates

Primary source of short-term fuel for the body especially for brain function and physical exercise.

• Used to build other molecules and structures in the cell.

• Common foods: grains (wheat, rice), vegetables, fruits, legumes (lentils, beans, peas), seeds, nuts and milk products.

Lipids

Major form of stored energy

• Stored as ‘adipose tissue’ (body fat)

• Energy source during rest or low- to moderate-intensity exercise

o Used to make cell membranes and other complex molecules

o Common foods: oils, animal fats, seeds, and nuts

Proteins

50% of cellular content. Do most cellular work

o Required for structure, function, and regulation of organs, tissues, and body systems

o Support tissue growth, repair, and maintenance

o Common foods: primarily in meat, dairy, seeds, nuts and legumes. Small amounts also found in vegetables and whole grains

Vitamins

Do not supply energy (kcalories) to our bodies

o Micronutrients (required in smaller amounts)

o 13 vitamins assist in regulating MANY body processes

o Organic molecules (contain carbon)

• Can be destroyed: heat, light and chemical agents

Minerals

Do not supply energy (kcalories) to our bodies

o Food and the body contain major minerals and trace minerals

o 16 minerals essential for several body processes

o Inorganic substances (do not contain carbon)

• Indestructible: not vulnerable to heat, light or chemical agents

Water

o Essential nutrient

o Inorganic (does not contain carbon)

o Water is involved in nearly ALL body processes!

What is the science of nutrition?

Nutrition is the branch of science examining:

the nutrients in food & their actions within the body to impact health.

o ALL nutrition recommendations & guidelines

are developed a substantial amount of scientific evidence.

Scientific Method

Step 1: Develop A Question

Step 2: Hypothesis

Step 3: Experiment (Design a Study)

Step 4: Results/Interpretation

Path 1:

Step 5: Hypotheses Supported

Step 6: Hypothesis Consistently Supported

Step 7: Theory Recommendations

Path 2:

Step 5: Hypothesis Rejected

Step 6: Develop a new question

Observational Study

Studies in which large groups of people are observed. Used to identify a relationship or association between a (nutrition) factor & health (or disease). Correlations (Associations):

Experimental Study

Studies in which a change in diet, nutrient, or eating behavior is prescribed

• Investigators do interfere & try to influence health outcomes

• Used to identify ‘cause’ & ‘effect’ between a (nutrition) factor & health (or disease).

Why do we need nutrition recommendations?

Chronic nutrient imbalances → malnutrition & health risks and establish Nutrient Adequacy or Meeting requirements for normal physiological functioning.

What do nutrition Recommendations do?

• Prevent inadequacy

• Prevent Overconsumption

What is inadequacy?

intake is under requirements but doesn’t impact health

What is deficiency?

Intake is well-below requirements & leads to (-) health consequences

What is toxicity?

Intake well-above the upper limit that can damage cells & decrease function.

What are Dietary Reference Intakes (DRIs)?

Set of reference values for nutrients that help with:

• Assessing nutrient intakes and monitoring the nutritional health of Americans across 22 life-stage groups that apply to healthy people.

✓ Prevent nutrient deficiencies

✓ Decrease chronic disease risk

• Developing nutrition labels

• Developing dietary guidelines and food guides

• Ensuring foods and supplements contain safe levels of nutrients

• Creating patient and consumer counseling and educational programs

What is Estimated Average Requirement (EAR)?

verage daily amount of a nutrient that is estimated to meet the

requirement of 50% of healthy people

• The EAR amounts are specific to:

✓ Life Stage

✓ Gender

✓ Population (as a whole)

o If you consume less than requirement over time:

✓ Nutrient stores decline

✓ Can lead to nutrient inadequacy

✓ Can lead to nutrient deficiencies & health problems

What is a Recommended Dietary Allowance(RDA)?

The average daily amount of a nutrient that is recommended to meet the needs of 98% of healthy people

• The RDA amounts are specific to:

✓ Life Stage

✓ Gender

✓ Individuals (not Population-level)

• EAR is needed to set the RDA

• RDA = ”the standard” for most people

What is a Adequate Intake (AI)?

Average daily amount of a nutrient that is recommended when the RDA can’t be set

o Relies on scientific judgements

• Not based on evidence

• Less valid, less rigorous

What is a Tolerable Upper Limit(UL)?

Maximum daily amount of a nutrient that appears safe for most healthy people

o Beyond UL = likely to be toxic or cause adverse health effects

o UL helps protect against overconsumption

• e.g., dietary supplement use.

How did/do the EARs get set for each nutrient?

Each nutrient has a different indicator of adequacy & toxicity

Ex: Calcium: EAR is for bone health and UL is to prevent kidney stones

What is the Estimated Energy Requirement(EER)?

Average energy intake (kcals) to maintain energy balance

• Energy balance: calories consumed = calories used (energy in = energy out)

• EER applies to:

✓ healthy body weight

✓ physically active

• No UL for kcals

✓ Excess kcals (above EER) are not ‘toxic’

✓ Excess kcals (above EER) do not cause immediate adverse effects

✓ But, habitual excess kcals (above EER) → weight gain, increased risk of obesity

What is a Acceptable Macronutrient

Distribution Ranges (AMDR)?

Adequate intake of energy and nutrients:

• Support health

• Reduce risk of chronic diseases

o Ranges:

• 45-65% kcalories from carbohydrate

• 20-35% kcalories from fat

• 10-35% kcalories from protein

What are % Daily Value (DVs)?

% DV = How much a nutrient in 1 serving of food

contributes to the total daily diet and meeting DRIs

o Based on a 2,000 kcal diet (general advice, not

personalized)

• Help inform consumers make decisions what to eat/drink

✓ ≤ 5% DV of a nutrient/serving = LOW

✓ ≥ 20% DV of a nutrient/serving = HIGH

LOW and HIGH can both be helpful

✓ LOW is ‘helpful’ for things to consume in moderation

✓ HIGH is ‘helpful’ for things recommended to consume more of

What is Dietary Guidelines for Americans (DGAs)?

Food-based recommendations for healthy individuals, to help:

• Meet nutrient needs

• Promote health

• Prevent disease

o Used by the following:

• School Nutrition Programs (breakfast & lunch)

• Federal Foodservice (hospitals, correction facilities, military)

• Food Industry when developing new products

o DGAs: Developed by nutrition scientists/physicians after reviewing scientific evidence.

What are the 3 Healthy Dietary Patterns?

• Healthy US: types & proportions of foods Americans

  typically consumed but in nutrient-dense forms &

  appropriate amounts

• Healthy Vegetarian: types & proportions of foods

  Americans typically consume but in nutrient-dense

  forms & appropriate amounts but:

  • is void of all ‘meat‘

  • includes seafood, eggs, &

  dairy as key protein sources

  • includes more plant-based

  protein sources

• Healthy Mediterranean: developed from a dietary

  pattern in Greece, Italy, Spain, etc. that focused on:

  • Whole (natural) Foods

  ✓ Avocados, Olives, Tomatoes

  ✓ Salmon

  ✓ Broccoli, Spinach

  ✓ Quinoa, Wheat

  ✓ Olive Oil, Chickpeas

  • Limits Ultra-processed foods

  ✓ Sweets/Desserts

  ✓ Processed Meats

What are nutrient-dense foods?

Foods/beverages high in nutrients but relatively low in kcals.

What are Food Groups?

Categories of foods &

beverages that make up the diet. Assigned

by USDA (US Department of Agriculture)

What food groups are in the Foods to Eat category?

Foods to EAT

o Vegetables (all types & colors)

o Fruits (especially whole fruit)

o Grains (1/2 as whole grain)

o Dairy

• fat-free or low-fat milk, yogurt, & cheese

• lactose-free versions

• fortified soy beverages & yogurt alternatives

o Protein foods

• lean meats, poultry, & eggs

• seafood

• beans, peas, & lentils

• nuts, seeds, and soy products

o Oils (vegetable oils & oils in food)

What food groups are in the Foods to Limit category (Discretionary Foods)

Added sugars, saturated fat, & sodium, and limit alcoholic beverages.

o Added Sugars: <10% of calories, ages 2+

o Saturated Fat: <10% of calories, ages 2+

o Sodium: <2,300 mg/d, ages 14+

(less than that for <14 yrs)

o Alcoholic Beverages:

• Adults can choose not to drink or

• Limit intake to:

✓ ≤ 2 drinks/day for men

✓ ≤ 1 drink/day for women

• Drinking less is better than drinking more

what is the 85-15 Guide for Healthy Eating?

2000 kcal diet

• 85% = 1,700 kcal (food groups)

• 15% = 300 kcal (‘discretionary’)

✓ Added sugars

✓ Saturated fat

✓ Alcohol

What is the DGA Principle, Energy Balance?

energy intake = energy expenditure

What is the DGA Principle, Food-First Mentality?

All nutrient needs can (and should) be fulfilled with foods, not supplements, for most individuals.

What is the DGA Principle, Portion Size?

Target 1 serving/eating occasion but tailor this

depending on your needs

• Read ‘serving sizes’ on packages

• Estimate with some ‘handy’ guides

What is the DGA Principle, Moderation?

Consume low-nutrient dense, high-energy dense foods only occasionally

✓ (Some) ultra-processed foods

✓ Remember: only ≤15% of your diet should come from these foods

What is the DGA Principle, Variety?

Increased variety within food groups because not all foods are created equal

What are the Diet-Planning How To’s?

o Identify which DGA pattern you prefer

o Identify foods within the 5 food groups

o Identify which foods are rich in select macro- and micronutrients

o Consider foods you enjoy

o Choose a variety of foods from each food group

o Make dietary improvements little by little

o Be mindful of ultra-processed foods

Dietary Reference Intakes (DRIs) Review

• Prevent deficiencies

• Healthy populations

• Nutrients

• Contains 4 main component:

(EAR/RDA/AI/UL)

• “Need 2500 mg calcium/day”

Dietary Guidelines for Americans (DGAs) Review

• Healthy populations

• Foods (based on nutrient needs)

• Contains food groups to increase

• Contains foods to limit

• “Need 3 cups of milk/day”

Nutrition information is accurate when it is:

• Disseminated by nutrition-trained professionals

o Registered Dietitian (RD)

• Degree and clinical internship (with National Exam)

• Maintain up-to-date knowledge (registration)

• Sometimes state-mandated license to practice

o Nutritionists with Academic Degrees

• MS or PhD in Nutrition Sciences, Public Health, Related Field

✓ Academic Professors/Instructors

✓ Industry, Federal, NIH Research Scientists

✓ (Some) Physicians & Health Care Professionals

• Conveyed in a clear & understandable way

• Founded on high-quality scientific evidence

What is a Nutrient claim?

✓ FDA regulated & approved

✓ Specifically targeting the quantity or quality of a nutrient

✓ Example: “High Protein”: > 10 g protein; “Good Source: 5-9.5 g protein"

What is a Health claim?

✓ FDA regulated & approved

✓ Relationship between food and disease or health condition

✓ Example: “Diets low in sodium may reduce the risk of high blood pressure

False or misleading nutrition claims

False or misleading health claims

✓ Organic, Non-GMO, Gluten-free ≠ Healthy

✓ High protein or high fiber ≠ Healthy

✓ Low carbohydrate, low sugar, low fat ≠ Healthy

What are Structure-function claims?

✓ Made without FDA approval; does

not specific diseases... but alludes

to health benefits

✓ Examples: “Builds strong bones”;

“Satisfies hunger longer”

What is digestion?

Breaking down foods into smaller molecules (nutrients)

GI Anatomy

Gastrointestinal (GI) tract

• Flexible and muscular tube with a

continuous inner space (lumen)

• Extends from mouth to anus!

• Simplified path: Mouth, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum, Anus

What is Mastication?

•(chewing) to break apart food and mix it with

saliva

• Eases swallowing

Bolus

food that has been chewed and swallowed

GI Anatomy-Esophagus

Tube connecting mouth to stomach transporting food (i.e., bolus) into the stomach

GI Anatomy-Stomach

Main (temporary) food storage area that converts food to a semi-liquid (chyme).

Movement of bolus: upper to lower portion of

stomach, mixes with digestive juices to create chyme.

GI Anatomy – Small Intestine

Primary Site of Absorption of Macronutrients

Nearly all absorption of macronutrients

o Travels down three segments:

duodenum, jejunum, ileum

o ~10 feet long with surface area of 2700 square feet!

o Receives bile (from gall bladder)

o Receives digestive juices (from pancreas)

GI Anatomy – Large Intestine

Primary Site of Water Absorption

Colon, Rectum, Anus (exit)

• Colon segments: ascending → transverse → descending → sigmoid

• Withdrawal of water from chyme

~100 trillion microbes inhabit GI tract

• Bacteria, viruses, fungi, protozoa, archaebacteria, etc.

• Role in health, metabolism, and disease

• Differences in obese versus nonobese people

o Factors influencing GI bacteria

• Early life exposures

• Diet (meals and patterns)

What is Mechanical Digestion?

• Physical breakdown of food using various muscles

• Occurs throughout the GI tract, not just in the mouth

What are the 3 types of muscles used in mechanical digestion?

• Circular muscles (esophagus – anus)

✓ Internal, pushes food forward

• Longitudinal muscles (esophagus - anus)

✓ Exterior, shortens the segment, allows for mixing

• Diagonal (oblique) muscle (stomach)

✓ Additional mixing

What is Peristalsis (propulsion)?

• Circular & longitudinal muscles working together

✓ Moves chyme forward ; Rate & intensity of contractions vary on GI segment

✓ Factors that may interfere with peristalsis: stress, drugs, illness

What is Segmentation (mixing)?

• Circular muscles in stomach & small

intestine contract & relax

✓ Churns chyme to mix with digestive juices

✓ Promotes contact with absorbing cells

What are Sphincters (in the GI tract)?

• Circular muscle ‘values’

• Periodically & automatically opens & closes to allow food to pass

• Controls pace of GI tract contents

• Sphincters are needed anywhere there is a change in anatomy/physiology/function

Functions of the Upper Esophageal Sphincter (UES)?

• Senses foods & beverages, allows them to pass down the esophagus

• Prevents foods & beverages from entering trachea

Functions of the Lower Esophageal Sphincter (LES)?

Allows food to enter into the stomach & keeps gastric juices & chyme from going back into the esophagus (i.e., prevents GERD)

Functions of the Pyloric Sphincter (PS)?

• Controls when the chyme leaves the stomach

and enters the small intestine

• Opens & closes depending on acidity levels

Functions of the Ileocecal Valve (ICV)?

Valve between the small & large intestine that controls flow into the large intestine. Allows chyme to enter into the large intestine & prevents it from going back into the small intestine

Function of Anal sphincters?

• Sphincters keep anus closed as stool

collects in the rectum.

✓ Internal – circular muscle, involuntary

✓ External – striated muscle, voluntary

What is Chemical Digestion?

• Chemical breakdown of food via secretions

• Occurs throughout the GI tract, not just in the mouth

• Secretory organs: salivary glands, stomach, pancreas, liver, and small intestine

What are enzymes?

o Protein facilitator of chemical reactions

• Breaking down, making, or changing molecules

o Catalyst: enzymes remain unchanged

o Hydrolysis: addition of water to break molecule into small pieces

o Organ of origin + compound + -ase = enzyme

• Example: Gastric lipase = stomach enzyme that digests lipids

What are the secretions of digestion?

1.) Enzymes

2.) Saliva

o Moistens food for easy passage

o Protective role: teeth, mouth, esophagus,

stomach

o Enzymes initiate carbohydrate digestion

3.) Gastric juice

o Protein digestion (hydrochloric acid), Heartburn

o Mucus protects stomach lining

o pH below 2 (more acidic than lemon juice)

4.) Pancreatic juice

o Released via ducts into duodenum (small intestine)

o Enzymes act on all three energy nutrients:

• Carbohydrates, fats, and proteins

o Sodium bicarbonate

• Basic/alkaline

• Neutralizes acid in chyme from stomach

5.) Bile

• Produced: liver

• Concentrated, stored, released: gallbladder

• Squirts into duodenum

• Emulsifier (NOT an enzyme)

▪ Disperses fat in watery solutions

▪ Gives digestive enzymes access to fat molecules

Final Stage of digestion

Carbohydrate, fat, and protein = digested

o Vitamins and minerals = absorbed

o Undigested residues enter colon (large intestine):

• Fluids, dissolved salts, fiber

o Colon

• Intestinal bacteria ferment some fiber

▪ Produces water, gas, and fat = energy for colon

• Some fiber passes through unchanged

• Water and dissolved salts

▪ Recycled for use in other parts of body

o Rectum and anus

• Eliminate stool

What is Absorption?

Movement of smaller molecules (from

foods/beverages) out of the digestive tract and into the body via 2 different vascular (vessels) systems

Absorption-Esophagus and Stomach

No absorption takes place here

Absorption-Small Intestine

Majority of absorption of nutrients (except for water)

Absorption- Large Intestine

Majority of absorption of water

Absorptive System – Small Intestine

Villi

• Fingerlike projections on intestinal folds – thousands per fold!

• Imagine: like a sea anemone

• Select and regulate nutrients absorbed based on needs of body

o Microvilli

• Enzymes and “pumps” act on different nutrients

o Crypts

• Glands secrete intestinal juices = digestion

o Goblet cells

• Secrete mucus = protection

Transport Throughout the BodyL

Nutrients enter into 1 (of 2) vascular systems:

• Directly to blood vessels (aka: ‘circulation’ or

‘vascular system’)

✓ Water-soluble nutrients (can be dissolved in water)

✓ Smaller products of fat digestion

• Directly to lymphatic vessels, then to bloodstream

✓ Larger fats, fat-soluble vitamins (insoluble in water)

The Vascular System

o Closed system: heart + blood vessels

o Delivers oxygen (O=red) and nutrients

o Removes carbon dioxide and waste via

de-oxygenated blood (DO=blue)

o Normal blood flow:

• Blood (from lungs to heart)

• Heart

• Arteries (A=away)

• Capillaries → “Exchange zone”

• Veins

• Heart

• Blood (to lungs)

The Liver

o 1st to receive nutrients from GI tract (before heart)

o Largest solid organ in the body (3 lbs)

o Prepares absorbed nutrients for use in body

o Filters blood to detoxify harmful substances

(alcohol, drugs, bacteria, byproducts, etc.)

o Produces bile

o Storage site for glucose (glycogen) and

micronutrients

o Regulates production of proteins

o 500+ vital jobs!

The Lymphatic System

o One-way route, flows toward heart

o 3 main functions:

o Return of excess body fluid back to blood

o Removal of microorganisms

o Absorption of fats and fat-soluble vitamins

o Lymph vessels connect into bloodstream (10)

(near the heart, bypassing the liver)

Regulation of GI Tract

o Homeostatic regulation: Any self-regulating process initiated by the

body to maintain ‘balance’/stability while adjusting to changing

external conditions

• Hormones (endocrine) & nerve pathways coordinate most processes via negative

feedback loops

✓ Negative Feedback Loop: self-regulating system in which the product of the reaction feeds back to

inhibit/reduce the reaction back to homeostasis.

✓ Positive Feedback Loop: self-regulating system in which the product of the reaction feeds back to

stimulate/increase the reaction away from homeostasis.

Carbohydrates

sugars, starches, fibers

• Known as ‘Carbs’ or ‘CHOs’

• Sources of carbohydrates: plant foods

(grains, vegetables, fruits and legumes) and milk

• “Fattening” – not necessarily!

o Brain and red blood cells

• Fueled by glucose

o Muscles: energy for movement

• Glycogen (stored form of glucose): ~50%

CHO family:

• Monosaccharides: single sugars

✓ Simple carbohydrates

✓ Chemical composition: C6H12O6

✓ Glucose, fructose, galactose’

✓ Most abundant organic (carbon-containing) molecules in nature

• Disaccharides: pairs of monosaccharides

✓ Simple carbohydrates

✓ Maltose, sucrose, lactose

• Polysaccharides: strings of monosaccharides

✓ Complex carbohydrates

✓ Glycogen, starches, and fibers

Monosaccharides: Glucose

o Most abundant monosaccharide in nature

o aka: blood sugar, dextrose (manufactured from corn, chemically identical to glucose)

o Broken down in cells → produces energy

• Essential for all body activities

o Can be found in:

• Disaccharides: maltose, sucrose, and lactose

• Polysaccharides: glycogen and starch

Monosaccharides:

Monosaccharides: Galactose

o Galactose:

• Very small amounts found as single sugar in foods

• When combined with glucose = lactose (disaccharide in milk and other dairy products)

Monosaccharides: Fructose

• One of the sweetest sugars: stimulates taste buds to produce sweetness

• Occurs naturally in fruit, honey, and vegetables

✓ aka: fruit sugar

• When combined with glucose = sucrose (table sugar)

Disaccharides

o Simple carbohydrates

Pairs of monosaccharides

(all containing glucose)

• Maltose = glucose + glucose

• Sucrose = glucose + fructose

• Lactose = glucose + galactose

o Condensation

• Links two monosaccharides together

• Releases water (H2O) as by-product

o Hydrolysis

• Breaks a disaccharide in two

• Requires water (H2O) to take place

• Commonly occurs during digestion

Disaccharides: Maltose

(glucose + glucose)

• Produced by breakdown of starch (e.g. during digestion)

• Involved in fermentation (e.g. alcohol production)

✓ Minor constituent of only a few foods: barley (key ingredient in beer)

✓ aka: malt sugar

Disaccharides: Sucrose

(glucose + fructose):

• Sweetest disaccharide

• Most abundant disaccharide found in nature

✓ Sugar cane, sugar beets, fruits, vegetables, grains

✓ aka: table sugar

Disaccharides: Lactose

(glucose + galactose):

• Found in milk and milk products

✓ Lactose = provides ½ of total kcalories from skim milk

✓ aka: milk sugar

Polysaccharides

o Complex carbohydrates

o Formed by many glucose units plus other monosaccharides;

connected through carbon bonds

• Glycogen: storage (glucose) – animals

• Starches: storage (glucose) – plants

• Fibers: structure (various monosaccharides) – plants

Polysaccharides: Glycogen

o Storage form of energy in the body

o Glucose units

o Found in: meat to a limited extent, not

found in plants

• Food ≠ significant source

• Liver: up to 8% by weight = glycogen

(significant source of carbohydrate)

Polysaccharides: Starch

o Storage form of energy in plants

o Glucose units

o Found in: grains, root crops, tubers, legumes

• Grains = richest source

• Body hydrolyzes starch to glucose, uses glucose

for energy

• Global food staple

Polysaccharides: Dietary Fiber

o Found in all plant-derived foods

• Provide structure in stems, leaves, roots, skins, and trunks

• Made from a variety of monosaccharides (not just glucose)

• Bonds between monosaccharides cannot be broken by digestive

enzymes (unlike starches)

✓ aka: nonstarch polysaccharides

✓ Pass through the body undigested (don’t release any glucose)

✓ Don’t contribute energy / kcalories

Polysaccharides: Fiber (two types)

o Classified by solubility in water:

• Insoluble fibers: cannot dissolve in water

✓ Example: skins of corn kernels, celery strings

• Soluble fibers: can dissolve in water; more viscous and fermentable

✓ Viscous fibers: form gels in GI tract

✓ Fermentable fibers: digested by GI bacteria

✓ Example: fruit pectin

o Functional fiber: natural fiber extracted from plants or

manufactured, then added to foods or supplements to provide

health benefits

• Total fiber in foods = dietary + functional

Carbohydrate digestion

Goal: Break ingested foods into smaller

molecules for use by the body.

2 Types of Digestive Processes:

Mechanical Digestion:(Physical breakdown of food particles) & Chemical Digestion:(Chemical breakdown of food particles via enzymes)

Sites:

Mouth: Small amount of digestion (~5%). Salivary Amylase(from salivary glands)

Stomach: NONE!!!!• Stomach acid (HCl) neutralizes salivary amylase • No enzymes here for CHO digestion

Small Intestine: Most Digestion Occurs Here (~95%)! • Pancreatic Amylase (from pancreas)
Large Intestine: None but fermentation occurs