pepsin: Starts protein break down into polypeptides
Typsin: Breaks down protein into tripeptides
Chymotrypsin: Breaks down protein into tripetides
Unit 1 - Basics
Unit 2 - Macronutrients
Section 1: Carbohydrates
Brief Digestion:
Starting in the mouth, carbohydrates are broken down by Salivary Amylase. Then it goes to the stomach where it is compressed. Following the stomach it goes to the small intestine where it is then further broken down by pancreatic Amylase before the maltase, sucrase, and lactase breaks down and absorbs the chemicals.
Absorption:
Monosaccharides are exclusively absorbed in the small intestine. Intestinal cells absorb glucose and galactose by active transport. Fructose is absorbed by facilitated diffusion. Monosaccharides are transported to the lived for conversion to glucose.
Obesity Statistics:
41% of Americans are obese causing 173 billion US dollars. Americans consume an excess of calories from all foods.
Carbohydrate Loading:
Male Athletes: 50kcal/kg/day; Female: 45-50 kcal/kg/day
Delays fatigue in Athletes participating in events lasting 90+ minutes
3g’s of water are incorporated into muscle tissue along with each gram of glycogen.
Athletes can delay reaching “the wall” by consuming 30-60g of carbohydrates per hour of activity.
Fiber Statistics:
For every 7g/day of dietary fiber, there may be a 9% reduced risk of cardiovascular disease
Going beyond the recommended 25 g/38g does not provide additional benefit.
To maintain muscle glycogen, athletes engaging in 1-3 hours / day of moderate to high-intensity exercise should consume 6 to 10 g of carbohydrate per kg of body weight daily.
Section 2: Lipids
Three Major Classes of Lipids
Triglycerides: [essential fatty acid] - 3 carbon, 2 oxygen - Difficult to break down based on chain size
Phospholipids: [Non-essential fatty acid.] - Creates & Repairs cell membranes, assists in fat transportation in Blood.
Has only a singular double bond linking two carbon atoms
Polyunsaturated:
Has more than one double bond in the hydrocarbon chains
Function of lipids
Lipids: Source of food energy:
Lipids: Needed for the absorption of fat-soluble vitamins:
Body Fat: Increases Energy reserve
Body Fat: Regulates body function
Body Fat: Used for body Insulation:
TransFats
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A monounsaturated fat which has been chemically manipulated to introduce a double bond.
Differences:
Hydrogen atoms added to an unsaturated fatty food.
Increases risk of cardiovascular disease
Reduces the oxidation and rancidity of the product.
Major steps in lipid digestion and absorption:
Step 1: Inactive lipase in your mouth gets mixed with food.
Step 2: When the inactive lipase enters your stomach becomes activated allowing for some minor lipid breakdown
Step 3: The pancreas creates pancreatic lipase which is used in conjunction with the bile in the small intestine to increase digestion.
Bile: Keeps fats dispersed in particles increasing surface area.
Identify the function of lipoproteins
Lipoproteins are water-soluble structures which are meant to transfer lipids through the bloodstream.
Describe gallstones and strategies for dietary management
Gallstones are hardened deposits of bile located in the gallbladder which consists of Cholesterol.
Lipid consumption patterns. —> List recommended fat and cholesterol intake
Americans consume approximately 80g of fat per day. Fat should be 20-35% of your daily intake. 80 * 9 = 720. 720/2000*10 = 36%
Distinguish between HDL and LDL
LDL: Low-Density Lipoproteins: Carries cholesterol to cells, more = HDL: High-Density Lipoproteins: Carries cholesterol from tissue to the liver. Less =
Risk factors for developing cardiovascular disease:
NonModifiable Risk Factors: Family History, Age, race, being male.
Modifiable Risk Factors: Hypertension, Diabetes mellitus, High blood cholesterol [LDL], Excess Body Fat, Physical inactivity, Tobacco use, Untreated sleep apnea.
Summarize dietary and lifestyle factors that reduce the risk of atherosclerosis
Limit Saturated Fat intake: less than 10% kcals;
Limit Trans fats as much as possible;
Consume 5-10% of total energy in omega 6 fatty acids
Eat 8 ounces of cold water fatty fish per week
Limit consumption of animal foods.
Explain how fats stored in muscle and adipose tissue is used as an energy source during exercise
Hormone-Sensitive Lipase (HSL) facilitates the breakdown of adipose cell triglycerides into glycerol and FFA. FFA use is used for moderate-intensity physical activities. Major consideration is FFA is not stored in plasma.
The sources of fats for fitness are: Plasma Free fatty acids (ffas), Intramuscular triglycerides, Plasma triglycerides, Chylomicrons, Very-low-density lipoprotein
Describe dietary fat recommendations for athletes.
20-35% of energy should supplement an athlete's fat needs. Athletes should focus on Monounsaturated fatty acids & Omega-3 Fatty Acids
Section 3: Proteins
Primary function of proteins in the body:
Structural: Building material for cells and tissues;
Enzyme: Speeds up chemical reactions
Transport: moves substances in and out of cells
Movement: contracts muscles.
Regulation: adjusts cell activity
Receptor: binds molecules
Defense: assists in immune responses
Chemical Structure of an Amino Acid
Central carbon connected to an acid group, An amino group and an R group. R groups change which differentiates between different amino acids. Nitrogen is the main thing to look out for
Essential Versus Non Essential
9 Essential:
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
11 Non-Essential:
Alanine
Aspartic Acid
Glutanic Acid
Serine
Arginine
Cysteine
Glutamine
Glycine
Proline
Tysonine
Amino Acids can be used to form compounds.
Creatine: Used for ATP recycling
Melanin: Pigmentation.
Serotonin: Neurotransmitter / mood regulation.
Epinephrine: Adrenaline
Histamine: Immune response chemical.
Basic steps of protein synthesis:
Step 1: DNA unwinds inside a nucleus in order to expose the gene region.
Step 2: Messenger RNA copies the gene instructions to move the instruction. Occurs in nucleus.
Step 3: RNA moves from nucleus to cytoplasm to locate ribosomes.
Step 4: Ribosomes translate and read the RNA instruction.
Step 5: Each Transfer RNA locates and collects particular amino acids.
Step 6: Amino acids are delivered to the ribosome
Step 7: Once the creation of the protein has been completed, the polypeptide is released
Foods with Complete/incomplete proteins:
Complete Protein: contains all essential amino acids to support deposition of protein in tissue.
Soy
Animal Meat
Quinoa
Egg white
Incomplete Protein: lacks/(inadequate-amount-of) one or more essential amino acids.
The limiting amino acid is the most concerning as it is the one with the lowest quantity
Most plant sources
Dietary Protein Recommendation
10-35% of total kcals
0.8 g/kg of body weight
Used for growth + Recovery
How are proteins digested in the digestive tract:
pepsin breaks down proteins into smaller polypeptides. The trypsin and chymotrypsin breaks down say polypeptides into smaller peptide ands amino acids. When Di/tri-ceptides encounter microvilli, they are broken down further.
Explain the importance of protein in Excersize:
Prior to exercise:
Protein and Carbohydrates should be eaten in tandem pre workout
During Exercise:
Muscles lose protein during prolonged physical activity,
Exercising while eating Carbs and protein has been shown to promote optimal recovery.
After Exercise:
Muscle cells repair themselves by synthesizing new protein