Nutrition Exam 2

Why are fats important in cooking? In the body?

Cooking: for flavor, texture appearance, mouthfeel, and emulsifier

Body: energy source, insulation, cushion, part of cell membrane, can be made into other substances

Are lipids organic?

Yes, because they contain carbon

What are the three general categories of lipids?

1. Triglycerides

2. Phospholipids

3. Sterols

What are the parts of a triglyceride?

Glycerol & 3 fatty acids

Compare and Contrast the general characteristics of saturated and unsaturated fatty acids-structures, sources, health effects

Saturated: every carbon has 2 hydrogens, solid at room temp., increases risk of heart disease

Unsaturated: 1-2 or more double bonds, liquid at room temp., reduce risk of heart disease

In general terms, describe the FA composition of canola oil, olive oil, butter, fat, and coconut oil

Liquid at room temp: canola oil and olive oil

Solid at room temp: butter, fats, coconut oil

Fact to know!

omega-3 and omega-6 fatty acids are precursors for longer chain fatty acids wit important physiological effects in the body

Why is DHA important for infants?

essential for the growth and development of the brain

What type of fatty acids are found in seed oils?

omega-6

Are seed oils “bad” or healthy?

When too much is consumed it can be bad and cause an increase in inflammation

What are health benefits of consuming omega-3 fatty acids?

reduce risk of heart disease, depression, dental disease, arthritis. Improves immune function, and brain development in infants

What are food sources of omega-3 fatty acids?

fish, soybeans, flaxseeds, walnuts, wheat-germ, and breast milk (infants only)

What advice do you have about including fish in the diet?

Should include variety, watch for mercury toxicity, eat 2-3 servings a week.

What is a potential concern with excessive fish intake?

Mercury toxicity which affects the brain

How is trans-fat different than a saturated fat?

Trans fats have an unsaturated fat that have at least one trans double bond

What foods/beverages naturally contain small amounts of trans-fats?

cow’s milk, dairy foods

How are most trans-fats made?

hydrogenation process which pumps in more hydrogen

What are trans-fats effects on health?

Increase risk of heart disease by raising bad cholesterol levels

How is the structure of a phospholipid different than that of a triglyceride?

Phospholipids replace on efatty acid chain by a group containing phophorus

What are key functions of phopholipids?

Part of cell membrane, emulsifiers (water & oil mix)

What are examples of sterols?

vitamin D, bile, some hormones

Why is cholesterol important to the body?

Important i structure of brain/nerve cells

Where is cholesterol made in the body and how much does this contribute to a person’s total blood cholesterol levels?

made in the liver, 2/3 total blood cholesterol

What is the function of all lipoproteins?

transport lipids through blood vessels

What are the four parts to a lipoprotein?

1. Chylomicrons

2. very-low density lipoprotein

3. low-density lipoprotein

4. high-density lipoprotein

What are the major classes of lipoproteins?

LDL: transport lipids from liver to other tissues such as muscle & fat

HDL: transport lipids from storage locations back to liver for dismantling

What are desirable blood lipid levels?

Cholesterol: <200mg/dl

LDL cholesterol: <100mg/dl

HDL cholesterol: >=40mg/dl males >= 50mg/dl females

Triglycerides: <150mg/dl

What are the dietary recommendations for total fat, saturated fat, linoleic acid, alpha-linolenic acid, and dietary cholesterol?

total fat: 20-35%

saturated fat: <10%

Linoleic acid: 5-10%

Alpha-linolenic acid: 0.6-1.2%

Cholesterol: as little as possible

What are main functions of proteins in the body?

build new cells, part pf hardened structure, acid/base balance, enzymes, clotting blood, anti-bodies, transporters, energy

What makes an amino acid different than a fatty acid or carbohydrate?

Contains nitrogen and sometimes sulfur.

What are the four components to the chemical structure of an amino acid?

Amine (NH2), Carboxylic acid (COOH), hydrogen. unique “R” group

How many different amino acids exist in nature?

20

What is the definition of an essential AA?

body cannot produce enough and is needed for the body to function

List the essential AA’s

Theronine, valine, tryptophan, isoleucine, leucine, lysine, methionine, phenylalanine, histidine

What is a conditionally essential AA and what is an example of when an AA becomes conditionally essential?

a non-essential amino acid that becomes essential under certain conditions such as liver or kidney disease.

What type of bond holds together AA?

peptide bond that is strong because its covalent

Contrast the primary, secondary, and tertiary structures of proteins

primary: line of amino acids

secondary: start of coiling (alpha-helix/ beta-pleated sheets)

tertiary: coiled into a ball (most exist at this stage)

Protein digestion and absorption

digestion: mouth/stomach (pepsin/HCL)

absorption: small intestine (trypsin/ exopeptidase), large intestine

What happens to the amine group of an AA once that AA is metabolized for energy?

The amine (N) group is left

Amine group to the liver to urea to kidneys to excreted

What are the potential concerns of consuming too much protein?

more ammonia in the body, dehydration, adipose fat

Calculation for protein

0.8g/kg per day

lbs/2.2=kg

List examples of times when protein needs increase?

pregnancy, breast-feeding, periods of rapid growth, serious illness, blood losses, burns

Describe potential benefits and drawbacks to consuming a diet with 20-30% of kcals coming from protein

Advantages: blood sugar regulation, weight loss

Disadvantages: cardiovascular disease, kidney stress

What is a food allergy and symptoms?

Allergies are the body’s immune system reacting inappropriately to one or more harmless substances in food.

Symptoms: hives, swollen/itches, eczema, difficulty swallowing, wheezing, abdominal pain, vomiting, diarrhea, anaphylaxis

What is anaphylaxis and how is it treated?

closing of throat/ airway is blocked and person can’t breathe. Treated with an epipen.

Common food allergies

cow’s milk, shellfish, eggs, fish, peanuts, sesame, soybeans, tree-nuts, wheat

How do health professionals test for allergies?

Skin patch testing on their back

What is celiac disease and how is the condition diagnosed?

autoimmune disease, gluten cannot be absorbed, damage to intestinal mucosa. Testing is done by antibody test or intestinal biopsy

What are examples of gluten-free grains?

quinoa, corn, rice

Does a gluten-free diet help a person to lose weight?

No, this diet was made for people who can’t eat gluten

Contrast nutrigentics and nutrigenomics

Nutrigenetics: genetic variations influence body’s response to food

Nutrigenomics: Nutrients affect the person’s expression of a genome

Describe general characteristics of maramus and kwashiorkor

Marasmus: severe malnutrition leading to energy deficiency; characterized by extreme weight loss and muscle wasting. Kwashiorkor: protein deficiency despite adequate calorie intake; characterized by edema, irritability, and changes in skin and hair.

What is food insecurity?

Unable to consistently access enough nutritious foods necessary for a healthy life.

How many americans are food insecure?

1 in 6

What percentage of food is wasted in the US?

40%

What are two examples of hunger-related work being done on UK’s campus?

Campus kitchen and big blue pantry

What is the difference between an anabolic and a catabolic reaction?

Anabolic: Larger molecules, built from smaller molecules (glucose to glycogen)

Catabolic: breakdown of larger molecules into smaller ones (glycogen to glucose)

What is ATP?

The body’s quick energy source, adenosine triphosphate

How efficient is the human body at converting energy into work?

25%

Why is it important to convert pyruvate and Acetyl CoA to glucose?

To be able to make ATP for the body to use for energy

Glycolysis is the process by which six-carbon ____ is broken down to form ____ three carbon molecules called ____. Glycolysis is an _____ process, meaning that is does not require oxygen. Glycolysis occurs in the ______ of the cell. There is a net gain of ___ ATP per molecule of glucose that enters glycolysis. This is a ____ process such that pyruvate can also be converted back into glucose. Glucose is the preferred energy fuel for the central nervous system.

glucose, 2, pyruvate, anaerobic, cytoplasm. 2, reversible

Pyruvate dehydrogenase is the enzyme that catalyzes the conversion of ____ to ____ in the _____ of the cell. This is a _____ reaction that is ____, it requires oxygen. This is one of the most nutritionally-important reactions in metabolism. There are four vitamins that are essential for this reaction to occur.

pyruvate, acetyl CoA, mitochondria, non-reversible, aerobic

The krebs cycle occurs in the _____ of the cell. Unlike glycolysis, this is an ____ process, meaning that it requires oxygen. As the name implies, the TCA cycles is just that, a cycle. The first step in this process is the input of Acetyl CoA into the cycle. There is the potential to gain ___ total ATP from the complete oxidation of one molecule of glucose through glycolysis and the TCA cycle. This energy is actually ultimately generated through the process of _____ and ______.

Mitochondria, aerobic, 36, oxidative phosphorylation, electron transport chain.

What four B-vitamins are essential for the conversion of pyruvate into acetyl CoA?

Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5)

What is lactic acid? How do you get rid of it?

Lactic acid is what glucose converts to when pyruvate can not be made during intense physical activity. Can get rid of by stretching and breathing deeply.

How are triglycerides broken down?

Glycerol: through glycolysis intermediate converted to pyruvate and glucose

Fatty Acids: through beta-oxidation converted to Acetyl-CoA

When does the body shift to ketosis and how do these ketone bodies affect the pH of our blood?

In starvation state and when there are no longer carbohydrate store available for energy. Decreases pH and makes it more acidic

What is the difference between transamination and deamination reactions?

Deamination: getting rid of nitrogen group in the urea cycle

Transamination: recycling the nitrogen to make whatever amino acid the body needs.

Example of a transamination reaction including enzymes required

Alanine uses PLP to convert to pyruvate

Pyruvates goes to alpha-ketogluterate

Alpha-ketogluterate uses ALT enzyme to make glutamate