Intro to Nutrition midterm

Chapters 1-5

Lipids

Category of compounds containing carbon, hydrogen, and oxygen that are hydrophobic (insoluble in water)

Triglyceride

A type of lipid, commonly known as fat. Most common.

Three fatty acids connected to glycerol ‘backbone’

Fats Functions in Food

Flaky textures, tender meats, flavor and aromas, contribute to satiety

Fats and Lipids Bodily Functions

Energy storage, insulation, transport of compounds in blood, cell membrane structure

Three Types of Lipids in Food and Body

Triglycerides, phospholipids, sterols

Fatty Acid

chain of carbon and hydrogen atoms with acid group

20 different types that vary by length, single or double bonds, and total double bonds

Basic unit of triglycerides and phospholipids

Three Main Types of Fatty Acids

Saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids

Saturated Fatty Acids

All carbons bonded to hydrogen

Solid at room temp

You should eat no more than <7% to 10% of total calories

Monounsaturated Fatty Acids

One double bond

Liquid at room temp

Ex) olive oil

Polyunsaturated fatty acids

More than one double bond

Trans. Fat

Type of fat that lowers good/HDL cholesterol

Worse for heart health than saturated fat

Fat

You should eat no more than 20% to 35% of total calories

9 calories per gram

Fish, flax seeds, seed oils

good sources of essential fatty acids

Phospholipids

Have a glycerol backbone

Lipoproteins

transport fat through the lymph and blood

Chylomicrons

carry digested fat through lymph into bloodstream

Very low density lipoproteins

deliver fat made in liver to cells

Low density lipoproteins

deposit cholesterol on walls of arteries (bad cholesterol)

High density lipoproteins

remove cholesterol from body and deliver to liver for excretion (good cholesterol)$

Cholesterol

part of cell membranes

Your body makes all it needs

Fat substitutes

designed to provide all the creamy properties of fat for fewer calories and total fat grams

Nutrients

Chemical compounds in foods to provide fuel for energy, growth and maintenance, and to regulate body processes

Six Classes of Nutrients

Carbohydrates, lipids, proteins, vitamins, minerals, water

Carbs, lipids, proteins

Provide energy in form of kilocalories

Vitamins, minerals, water

Help regulate many body processes including metabolism

Nutrition

The science that studies how nutrients and compounds in foods nourish you, help you function, and affect body functions and health

Macronutrients

Energy-yielding nutrients needed in higher amounts

Ex) carbs, lipids, proteins

Micronutrients

Needed in smaller amounts

Ex) vitamins and minerals

Carbohydrates

Supply glucose, a major energy resource

Fats (lipids)

Cushion organs, insulate body to maintain body temperature

Proteins

Growth and maintenance of muscle, tissues, and organs

Makes certain hormones, enzymes, and healthy immune system

Transports other nutrients

Phytochemicals

Nonnutritive compounds in plant foods that may play a role in fighting chronic diseases

Fiber

The portion of plant foods that isn’t disgested in the small intestine

The average American diet is high in what?

Added sugar, sodium, saturated fat, and calories

The average American diet is low in what?

Vitamin D, calcium, potassium, fiber, iron

Obesity rates in America

Adults: over 70% overweight, 40% obese

Children: over 16% obese

Effects of Poor Nutrition

Type 2 diabetes, heart disease, cancer, stroke

Key Principles of healthy eating

Balance, variety, moderation

Undernutrition

Not meeting the nutrient needs

Overnutrition

Excess nutrients and/or calories in diet

Malnourished

Long-term outcome of consuming a diet that doesn’t meet nutrient needs

Tools to Help Avoid Under and Overnutrition

DRI’s, dietary guidelines for Americans, MyPlate

Dietary Reference Intakes (DRI’s)

Tell you how much of each nutrient you need to consume to maintain good health, prevent chronic diseases, and avoid unhealthy excesses

MyPlate

The most recent food guidance system for Americans. Promotes concept of mean planning, healthful choices, proportionality, moderation, variety, and personalization

Portion for MyPlate

Half should be vegetable, smaller for grains, lean protein food, fat-free and low-fat diary foods

Nutrient density

Refers to the amount of nutrients a food contains in relationship to the number of calories it contains

Energy density

Refers to foods that are high in energy but low in weight or volume, more calories per gram

Food Label

Tells you what’s in the package. Mandated by FDA (food drug administration)

Zoochemical

Compound in animal food products that benefit health

Ex) omega-3 fatty acids

Functional Foods

Have a positive effect on health beyond providing basic nutrients

Digestion

The process of breaking down food into individual molecules small enough to be absorbed through the intestinal wall

Absorption

The process of moving nutrients from the gastrointestinal (GI) tract into the circulatory system

Transport

The process of moving absorbed nutrients throughout the body through the circulatory and lymph systems

Elimination

The excretion of undirected and unabsorbed food through the feces

Digestive Process

A multi step process of breaking down foods into absorbable components using mechanical and chemical means in the GI tract

Main Roles of GI Tract

Break down food into smallest components, absorb nutrients, prevent microorganisms or other harmful compounds in food form entering tissues of the body, maintain the gut micro biome

Organs of GI Tract

Mouth, esophagus, stomach, small and large intestines

Accessory organs: pancreas, liver, gallbladder

Mouth

Uses saliva, bolus, and epiglottis to break down food. Where digestion begins.

Saliva

Softens, lubricates, dissolves food particles

Bolus

Moves into pharynx, is swallowed, and enters the esophagus

Epiglottis

Closes off trachea during the swallowing to prevent food from lodging in the windpipe

Esophagus

Transfers food from the mouth to the stomach

The gastroesophageal sphincter is the bottom of the esophagus that narrows and relaxes to allow food into stomach. Closes to prevent back flow of hydrochloric acid from stomach

Stomach

Muscular organ that continues mechanical digestions by churning and contracting to mix food with digestive juices for hours

Stomach Digestive Secretions

HCI, digestive enzymes, and bolus/chyme

Small Intestine

Completes digestion of food and absorbs nutrients through its walls

Long, narrow, and coiled. 20 feet of GI tract. Filled with villi and microvilli. Separated intro 3 segments

Duodenum (shortest)

Jejunum

Ileum (longest)

Large Intestine

Absorbs water and some nutrients; passes waste products out of the body

Absorbs water and electrolytes. Has no digestive enzymes, the digestion is done by bacteria. 5 feet long, 2.5 inches in diameter. Has three sections:

Cecum, colon, rectum

Liver

largest internal organ of the body

Produces bile needed for fat digestion

Gallbladder

Concentrates and stores bile released into GI tract when fat is ingested

Pancreas

Produced hormones: insulin and glucagon regulate blood glucose

Produces and secretes digestive enzymes

Hormones

Released from the endocrine glands throughout the lining of the stomach and small intestine and regulate digestion

They control digestive secretions and regulate enzymes and cellular activity

Enzymes

Substances that produce chemical changes or catalyze chemical reactions

Steps of the Digestive System

Mouth: ingestion, mechanical and chemical digestion (chewing)

Esophagus: moving bolus from mouth to stomach

Stomach: Mechanical and chemical digestion, absorption

Small intestine: chyme, chemical digestion in pancreas, nutrients absorbed into blood and lymph

Large Intestine: residual food digested by bacteria, absorption of salt water and vitamins, feces

Rectum: Elimination of stool via anus

Peristalsis

The muscular rhythmic contractions that occur throughout the GI tract are called

Carbohydrates

Found primarily in plant-based foods

Most desirable form of energy for body

DRI: 130 grams per day, 4 kcals/gram

Simple Carbohydrates

contain monosaccharides and disaccharides

Monosaccharides

One sugar unit

Glucose, fructose, galactose

Disaccharides

two sugar units (two monosaccharides joined together)

Maltose= glucose+glucose

Sucrose= (table sugar) glucose+fructose

Lactose= (milk sugar) glucose+galactose

Polysaccharides

complex carbohydrates

Starch, fiber, glycogen

Starch is the storage form in plants

Amylose

straight chains of glucose units

Amylopectin

branched chains of glucose units

Fiber

non-digestible polysaccharide

Total fiber= dietary fiber+functional fiber

DRI= 14 grams per 1,000 cals

Americans fall short about 16 grams

Dietary fiber

naturally found in foods

Functional fiber

added to foods for beneficial effect

Soluble fiber

dissolves in water and is fermented by intestinal bacteria

Insoluble fiber

cellulose, hemicellulose, lignins

Moves rapidly through GI tract, laxative effect

Glycogen

storage form of glucose is animals

Stored in liver and muscle cells

Lactose

principal carbohydrate found in dairy products

People with deficiency of enzyme lactase cannot digest lactose

Lactose malabsorption

natural part of aging

People can still consume dairy, should not eliminate it

Lactose intolerance

when lactose malabsorption results in nausea, cramps, bloating, diarrhea, and flatulence within two hours or eating or drinking foods containing lactose

Tips for tolerating lactose

gradually add dairy to your diet

Eat smaller amounts throughout the day

Eat it with a meal or snack

Try reduced lactose produces

Lactase pills

Functions of carbohydrates

provide energy

Maintain blood glucose levels

Prevents ketosis and protein breakdown for energy

Ketosis

results from fat breakdown when not enough glucose is available

Blood Glucose Levels

Body wants to keep between 70mg/dL and 100mg/dL

Two hormones responsible are insulin and glucagon

Insulin

Lowers blood glucose levels

Needed for glucose to enter cell from the bloodstream

Liver, kidney, and brain cells can use glucose without it

Glucagon

Increases blood glucose levels

Stimulates the release of glucose into the blood

Grains

Important staple and source of nutrition

Three edible parts: bran, endosperm, germ

Refined Grains

milling removes bran and germ

Some vitamins, iron, phytochemcials and dietary fiber are lost a result

Enriched grains

Folic acid, thiamin, niacin, riboflavin, and iron added to restore some of the lost nutrition

Whole-grain

contain all three parts of kernel

Fiber Food Sources

Vegetables, fruits, grains, proteins

Ex) Broccoli, apples, brown rice, kidney beans