NUTR 202 Exam 2

Material from Chapters 5-7

What are the 3 types of lipids found in food and the body?

Triglycerides (fats), phopholipids, and sterols

What are functions of fats lipids in the body?

• energy storage

• insulation

• transport of compounds in blood

• cell membrane structure

What is the major form of fat in the body and in foods?

Triglycerides

Triglyceride

three fatty acids connected to glycerol backbone

• most common lipi found in foods and body

• fats!

Phospholipids

glycerol backbone but with two fatty acids and a phosphorous group

• think mrs. leibl

• hydrophobic head, hydrophylic tail

Sterols

composed of four connecting rings of carbon and hydrogen

Cholesterol

• precursor of very important compounds in body

  • vitamin D, bile acids, sex hormones

• not required in diet since body makes all it needs

Saturated fatty acids

All carbons bonded to hydrogen

• food source: coconut oil

Monounsaturated fatty acids

one double bond in the carbon chain

• food sources: olive oil, peanut oil, canola oil, nuts, and avocados

• THE HEALTHIEST FAT

Polyunsaturated fatty acid

two or more double bonds in the carbon chain

• Food source: Omega-6 and Omega-3 fatty acids (fatty fish)

What are the 2 essential fatty acids?

Linolenic acid (omega-6) and Alpha-linolenic acid (omega-3)

Why are the essential fatty acids important?

• They help maintain healthy skin cells, nerves, and cell membranes

• precursors to eicosanoids, eicosapentaenoic acid, and docosahexaenoic acid

Emulsifier

keeps oils and water mixed together

• phospholipid bilayer

Lecithin

major phospholipid in the cell membrane

• used as an emulsifier in foods

Hydrogenation

process in which trans fats are created

• adds hydrogen atoms to liquid vegetable oils to extend shelf life and improve texture

Cis

hydrogens are on the same side of the double bond

Trans

hydrogens are on opposite sides of the double bond

Why is trans fat intake important for consideration?

they are worse for your heart health

• raise LDL cholesterol

• lower HDL cholesterol

Sources of trans fats in American Diet

Processed and packagesd foods, partially hydrogenated oils, fried foods

Cholecystokinin

hormone that stimulates the pancreas

Why is bile important in lipid digestion?

emulsifies fat, breaks down fat globules into smaller pieces

Micelles

small carriers for absorption

• lecithin + monoglycerides and fatty acids

Enzymes in lipid digestion

• lingual lipase

• gastric lipase

• pancreatic lipase

Which enzyme is responsible for most lipid digestion?

Pancreatic Lipase

What is absorbed from the digestion of trglycerides?

• two fatty acids

• one monoglyceride

What happens to long chain fatty acids after absorption?

enter the lymph

• they need TRANSPORT CARRIERS

4 Lipoproteins

1. Chylomicrons

2. Very low-density lipoproteins (VLDL)

3. Low-density lipoproteins (LDL)

4. High-density lipoproteins (HDL)

Chylomicrons

carry digested fat through lymph into bloodstream

Very Low-density Lipoproteins

deliver fat that was made in the liver to cells

Low-Density Lipoproteins

deposit cholesterol on walls of arteries

• aka the bad cholesterol

High-Density lipoproteins

remove cholesterol from the body and deliver it to the liver for excretion

• aka the good cholesterol

Functions of fats in FOODS

• Give flaky texture to baked goods

• Make meats tender

• Provide flavor and aromas

• Contribute to satiety

Functions of fats in the BODY

• energy storage

• insulation

• transport of compounds in the blood

• cell membrane structure

Cholesterol in food come from

Animal sources

DRI total fat

AMDR of 20-35%

DRI of Saturated Fat

10% of total calories consumed

What should we do with trans fat in our diets?

Minimize our intake!

Fatty fish that are high in mercury

swordfish, shark, king mackerel, tilefish

Why should pregnant women avoid fish with mercury?

Methylmercury is a toxic chemical especially harmful to the nervous systems of unborn children

Risk factors for heart disease

• age

• gender

• family history

• and T1 diabetes

• no exercise

• weight gain

• smoking

• low HDL

• high LDL

Metabolic Syndrome

group of risk factors that increase the risk of heart disease

• include insulin resistance, HBP, centralized obesity, low HDL, and high triglycerides

Desirable level for total cholesterol

< 200

Desirable level for LDL

< 100

Desirable level for HDL

> 60

How to lower risk for heart disease

1. minimize saturated and trans fats, and cholesterol in diet

2. include fish in weekly diet

3. eat lots of plant foods

4. eat foods rich in antioxidants and phytochemicals

5. do lots of exercise and manage weight

6. moderate use of alcohol

7. whole is greater than the sum of its parts

Mediterranean Diet

Plant-based diet

• whole grains, fruit and veg, legumes, and nuts

• olive-oil, low fat dairy, and water

Basic building blocks of protein

Amino Acids

Difference between protein and carbohydrates and lipids

Structure and function

Essential Amino Acid

• nine total in the body

• cannot be made in the body

• must be from the diet

Non-essential amino acid

• eleven total in the body

• can be synthesized in the body from other amino acids or by adding nitrogen to carbon-containing structures

Complete Protein

all essential proteins present + some nonessential ones

Incomplete Proteins

low in one or more essential amino acids

• sources: plant foods

Complementary proteins

do not need to be eaten in the same meal, only the same day

• ex: Grains and Vegetables → Pasta and Tomatoes

• think partner proteins

Complete Proteins: Plant sources

soy and quinoa

Denaturation of Protein

alteration (unfolding) of a protein’s shape, which changes the structure and function of the protein

3 ways protein can be denatured

1. change in texture

2. untangling of protein in digestion

3. change in 3D structure

Gastrin

hormone that stimulates gastric juice including HCl and pepsin

Small Intestine Digestion of Protein

• Cholecystokinin stms release of pancreatic enzymes

• Proteases digest polypeptides to form shorter remnants

• polypeptides are broken down into tripeptides, dipeptides, and amino acids

• Amino Acids travel to next organ

Digestion Protein Tract

Stomach (polypeptides) → Small Intestine (amino acids) → Liver

HCl

denatures protein and activates pepsin

Pepsin

enzyme that begins breaking down protein in stomach

Smaller polypetides travel to the…

small intestine

Cholecystokinin

stimulates the release of pancreatic enzymes

Proteases

digest polypepetides to form shorter remnants for absorption

Polypeptides in the SI are brokwn down into

• tripeptides

• dipeptides

• amino acids

What is absorbed from protein digestion

individual amino acids

What is the final destination of protein digestion

Small Intestine

How do amino acids leave intestinal cell

circulatory system

Sources of Amino Acids

1. Diet

2. Breakdown of proteins in the body

5 Bodily Uses of Amino Acids

1. Make body proteins

2. Make nonprotein substances (thyroid hormones)

3. Burned for Energy

4. Stored as Fat

5. Made into Glucose

Waste product of Protein Breakdown

Urea

Where is urea formed?

The liver

How is urea excreted?

By the kidneys

Importance of Urea excretion for kidney disease

kidney disease doesn’t allow the kidneys to filter through waste products in the blood properly which can cause severe symptoms

Body Functions of Proteins

• provide structural and mechanical support

• maintain body tissues

• make up most enzymes and hormones

• help maintain fluid balance

Edema

swelling caused by excess fluid trapped in body tissues

• relation to protein → protein deficiency leads to fluids to pull back into the blood vessels

RDA for protein

• convert weight to kilograms by dividing pounds by 2.2

• multiply weight in kg by 0.8 to get RDA of protein

Protein Equillibrium

Amount of nitrogen consumed = Amount of nitrogen excreted

Positive nitrogen balance

Nitrogen retained > amount excreted

• think bodybuilders, pregnant women

Negative nitrgen balance

Amount excreted > Nitrogen retained

• starvation, you don’t eat anything but you’re still excreting stuff

Effects of Too Much Protein

• increased risk of heart disease

• kidney stones

• calcium loss from bones

• can displace other nutrient/fiber rich foods

• decrease in kidney function

Protein-energy malnutrition

• inadequate protein and/or calories

• more common in children

• factors: poverty, poor food quality, etc.

Kwashiorkor

severe deficiency of dietary protein

• edema, muscle loss, skin rashes

• seen in children eating low protein cereals

Marasmus

severe deficiency of calories

• emaciation, lack of growth, loss of fat stores

Marasmic kwashiorkor

worst of BOTH conditions

Treatment of Marasmic Kwashiorkor

1. Address life threatening factors (severe dehydration and fluid/nutrient imbalances)

2. Restore depleted tissue

   • gradually provide nutritionally dense kcals and high-quality protein in the diet

Vegan Diet

Does eat

• grains, veg, fruit, legumes, seeds, and nuts

Doesn’t eat

• animal foods, meat, fish, poultry, dairy foods, and eggs

Lacto-vegetarian

Does eat

• grains, veg, fruit, legumes, seeds, nuts, dairy foods, eggs

Doesn’t eat

• meat, fish, and poultry

Ovo-vegetarian

Does eat

• grains, veg, fruit, legumes, seeds, nuts, and eggs

Doesn’t eat

• meat, fish, poultry, and dairy foods

Risks of Vegetarian Diets

Potential deficiencies of nutrients found in animal foods

• protein, iron, zinc, calcium, Vitamin D, Vitamins B12 and A, and Omega-3 fatty acids

Fat-soluble vitamins

absorbed with dietary fat → stored in body

• A, D, E, K

Water-soluble vitamins

absorbed with water and enter the bloodstream directly → not stored in the body

• B and C

Coenzyme

small. non-protein organic molecule that binds to an enzyme to help it catalyze a chemical reaction

Vitamins that are Coenzymes

Thiamin (B1), Riboflavin (B2), Niacin (B3), B6, and Vitamin C

Vision Vitamin

A

Collagen Vitamin

C

Coagulation Vitamin

K

Bone Vitamin

D

Neural Tube birth defects Vitamin

Folate

Synthesis of Nonessential Amino Acids Vitamin

B6