Nutrition Final Exam Davis TCU

Energy yielding nutrients

carbs (4 kcal/g), proteins (4 kcal/g), lipids (9 kcal/g); used to fuel all activities in the body; excess nutrients are turned into storage, either as fat or as glycogen

Organic nutrients

contain carbon,

carbohydrates, proteins, fat, and vitamins

Inorganic nutrients

Do not contain carbon and maintain identity through changes

Minerals, and water

DRI (dietary recommended intakes)

A set of values for the dietary nutrient intakes of healthy people

RDA (recommended daily allowance)

The average amount of a nutrient considered adequate to meet the needs of all healthy people

EAR (estimated average requirements)

The amount of a nutrient that will maintain a specific biochemical or physiological function in ½ the people of a given age and gender group

AI (adequate intakes)

The average amount of a nutrient that appears sufficient to maintain health

TUIL (tolerable upper intake levels)

The maximum amount of a nutrient that appears safe and beyond which there is a risk of adverse health effects

Enriched foods

An addition to a food of specific nutrients to replace losses that occur during processing so that the food will meet a specific standard

Fortified foods

Addition to a food of nutrients that were either not originally present or present in insignificant amounts

Ingredient list

Listing of all ingredients in descending order of predominance by weight

Serving sizes

Adjust calculation according to amounts consumed

Nutrition facts- required information

Total food energy and energy from fat

Total fat, saturated fat, trans fat, & cholesterol

Sodium

Total carbohydrates, dietary fibers, & sugars

Protein

Vitamin A&C, iron, and calcium

Daily values

recommendation found in a specific serving of food for key nutrients based upon a 2000 kcal diet

-greater than/equal to 20%= high of excellent source

-10-19%= good source

-less than/equal to= low source

Gastrointestinal tract (GI tract)

Flexible muscular tube from the mouth→esophagus→stomach→small intestine→large intestine→rectum→anus

Principal organs of absorption and digestion

Stomach

Intestine

Lumen

Inner space within the GI tract

Mouth

Begins digestive process- motility and secretion

Bolus

The amount of food swallowed at one time

Pharynx

A short tube shared by both digestive system and respiratory system

Epiglottis

Protects the airway during swallowing

First regulation of intake

Esophagus

passes food from mouth→ stomach, primary function is motility, passes through a hole in the diaphragm

Upper esophageal sphincter

Opens during swallow

Cardiac or lower esophageal sphincter

Prevents reflux (backflow of content)

Sphincter

A circular muscle surrounding and able to close a body opening

Stomach

Adds acid, enzymes, fluid to bolus- bolus becomes chyme, chyme is released to the small intestine through the pyloric sphincter

Chyme

A semiliquid mass of partly digested food expelled by the stomach into the duodenum

Small intestine

Secretes enzymes that digest all energy-yielding nutrients and the major site of nutrient absorption and digestion

Pancreatic duct

Conducts pancreatic juice (enzymes/bicarbonate) from the pancreas to the small intestine

What does the pancreas release?

Bicarbonate to neutralize the acid and we can absorb better

Large intestine

reabsorbs water & minerals and passes waste & unabsorbed nutrients like fiber on to the rectum for elimination

Rectum

Muscular terminal part of the intestine

Anus

Final sphincter muscle and terminal outlet of the GI tract to pass stool (feces) out of the body

Ileocecal valve

Separates the small and large intestine

HCL

An acid composed of hydrogen and chloride atoms that is normally produced by the gastric glands, breaks down proteins and creates an acidic pH in the stomach, helps with the absorption of calcium, iron, and B12

Bicarbonate

Secreted by the pancreas and neutralizes acidic chyme

Where does most digestion occur?

Small intestine

Where does most absorption occur?

Small intestine

Exocrine gland

Secretes materials out of the body into the digestive tract or onto the skin

What materials do exocrine glands excrete?

Enzymes

Endocrine gland

Secretes materials inside the body into the blood

What materials do endocrine glands excrete?

Hormones

What 5 organs are involved in secretions?

Salivary glands

Stomach

Pancreas

Liver (through the gallbladder)

Small intestine

Pancreatic juices and intestinal enzymes

Released through ducts into the duodenum

Enzymes act on all three energy nutrients- carbohydrates, lipids, and proteins

Salivary glands

Target organ is the mouth, Secretes saliva, salivary amylase- contains the digestive enzyme for starch

Stomach

secretes gastric juice- mixture of water, enzymes, and hydrochloric acid that acts primarily in protein digestion

Liver

Target organ is the gallbladder, secretes bile- bile emulsifies fat so that enzyme can have access to break it down

Intestinal glands

Target organ is the small intestine

Secretes intestinal juice

Intestinal enzymes break down carbohydrate, fat, and protein fragments

Mucus protects the intestinal wall

Secretin

secreted from the duodenal wall and stimulates the pancreas in response to acidic chyme in the small intestine bicarbonate-rich juices are secreted into the small intestine to maintain a slightly alkaline pH

Gastrin

Secreted from the stomach wall and stimulates the stomach glands in response to food in the stomach by secreting hydrochloric acid into the stomach to maintain an acidic pH

Cholecystokinin (CCK)

A hormone

Responds to fat or protein in the small intestine

Secreted from the intestinal wall

Stimulates the gallbladder and pancreas

Responds by: bile is secreted into the duodenum to emulsify fats; bicarbonate and enzyme-rich juices are secreted into the small intestine to maintain a slightly alkaline pH, it digests fats and proteins, and slows the GI tract motility

Which route are carbohydrates absorbed?

Carbohydrates end at the small intestine and go to the bloodstream from the portal vein to the liver

Which route are small lipids absorbed?

Lipids end at the small intestine and go to the portal vein to the liver

Which route are large lipids absorbed?

Lipids end at the small intestine and go to the lymph

Which route are proteins absorbed?

Proteins end at the small intestine and go to the bloodstream from the portal vein to the liver

Monosaccharides

Carbohydrate

Contains one saccharide molecule

Fructose

Monosaccharide

Sweetest sugar

Fruit sugar

Pentagon shape

Glucose

Monosaccharide

Also called dextrose

Not as sweet

Measured in blood as blood sugar or _____

Galactose

Monosaccharide

Seldom free in nature

Part of lactose (milk sugar)

Disaccharides

Carbohydrate

Consists of a pair of monosaccharides

Sucrose

Disaccharide

Glucose & fructose

Table sugar, also occurs naturally especially in fruit

Lactose

Disaccharide

Glucose & galactose

30-50% of milk energy

Maltose

Disaccharide

Glucose & glucose

Malt sugar, used in the germination of seeds & barley

Polysaccharides/ complex carbohydrates

Composed mainly of glucose units

Should contribute 45-60% of caloric intake

Starch

Glycogen

Starch

Polysaccharide (many monosaccharides)

Serves as a storage form of glucose in plants

Plant polysaccharide composed of glucose

Storage form of glucose in plants

Grains, root crops, tubers, & legumes

Long branched or unbranched chains of hundreds of thousands of glucose molecules

Major source of food energy worldwide

Richest food source is grains

Glycogen

A storage form of glucose in animals

Made and stored in the liver and muscles

More complex and branched than starch

Enzymes can attack all branches simultaneously

Occurs through a condensation reaction

Dietary fiber

Remains from food after passage through the small intestine prior to bacterial digestion in the colon through fermentation

Everything except lignins and cellulose are digestible

Structural part of plants

Different from starches

Viscous/ soluble

Insoluble

Phytic acid

Viscous/soluble fiber

Decreases cholesterol- binds bile acids

Decreases the rate of glucose absorption

Used to treat diarrhea

Fruit, oats, barley, & legumes

Insoluble fiber

Decreases transit time in the small intestine

Prevents some cancers

Must be used moderately by people with marginal intakes

Vegetables, wheat, & grains

Phytic acid

Found in fibrous foods

Husks of grains, legumes, & seeds

Binds minerals such as zinc, iron, calcium, magnesium, and copper

Cellulose

Fiber

Composed of plant cell walls

Composed of glucose molecules

Hemicelluloses

Fiber

Main constituent of cereal fibers

Pectin

Fiber

Carbohydrate backbone with monosaccharide side chains

Readily formed gel in water (viscous)

Fruits & vegetables

Gums & mucilages

Fiber

Plant secretes gums and the site of an injury

Guar & carrageenan→ common ___________ (used in food stabilizers)

Lignin

Fiber

Non-polysaccharide fiber

Tough

Benefits of fiber

Prevents colon cancer

It keeps you regular

Controls blood lipids and cardiovascular disease

Blood glucose and insulin modulation

Diabetes control

Appendicitis prevention

Diverticulitis prevention

Hemorrhoid prevention

Hydrolysis (catabolic)

Addition of water to break a molecule into smaller pieces - water is formed

Condensation (anabolic)

Two molecules combine to form a single molecule

Build it up

Constancy of blood glucose

Optimal functioning at a certain range

80-100 mg/dL (fasting)

Hunger occurs at 60-65 mg/dL

What two organs use glucose as an exclusive fuel source

Brain & nervous system

What does the pancreas respond in changes in levels to?

Glucose

If glucose levels are high, the pancreas secretes _____

Insulin

Insulin

A hormone that acts to take glucose out of the blood and deposit it into cells

If glucose levels are low, the pancreas secretes _____

Glucagon

Glucagon

A hormone that brings glucose out of the storage form in the liver

Epinephrine

is secreted by the adrenal gland

"Fight or flight" hormone elicit a release of glucose storage in the liver in times of stress

Gives a burst of energy

What happens when blood glucose regulation fails?

Diabetes

Hypoglycemia

Gluconeogenesis

The making of glucose from a non carbohydrate source

Occurs mainly in the liver

Glucose for fuel is required by the?

Brain

Nerve cells

Developing RBCs

Glycogenesis

In the liver, excess glucose molecules link through a condensation reaction to form glycogen

Where is the primary storage form of glucose?

The muscle and liver

What happens after a high carbohydrate meal?

Blood glucose rises & glucose enters the cells through the action of insulin

Glycogenolysis

The liver breaks down glycogen→ glucose through a hydrolysis reaction

When blood glucose falls

When are body proteins broken down?

When carbohydrate intake is inadequate

Normal blood sugar levels

Below 100 mg/dL

When is pre-diabetes diagnosed?

At 100 mg/dL

When is diabetes diagnosed?

At 126 mg/dL

Diabetes

Disorder of blood glucose regulation

Symptom: hyperglycemia (high blood sugar)

Type 1 diabetes

Juvenile onset

Less common

The pancreas is unable to synthesize insulin

The liver cannot secrete insulin

An injection of insulin is needed for cells to take up blood sugar

The insulin cannot be taken orally

It is called insulin dependent diabetes mellitus (IDDM)

Type 2 diabetes

The most common form of diabetes

Adult onset (old name)

Cells are resistant to insulin

Obesity is a major factor

Increased risk with age as the pancreas function decreases

90% of those with diabetes have type _____

Most people who have diabetes are not on insulin