Comprehensive Study Notes: Proteins, Water, Alcohol, Lipids, Carbohydrates, and Vitamins

Proteins

Protein Structure and Function

Proteins are essential macromolecules composed of amino acids, which serve various functions in the body including transport, regulation, structural support, and energy. - Monomers of proteins: Amino acids are the building blocks of proteins. - Primary structure: The sequence of amino acids; unaffected by acids and bases. - Secondary structure: Defines folded shapes (e.g., alpha helices, beta sheets). - Quaternary structure: Involves multiple subunits. - Denaturation: Caused by agitation, acids, salts, or heat; affects all structures except primary. - Protein functions: Transport, regulation, structural support, energy. Example: Hemoglobin transports oxygen in the blood. Additional info: The body uses 20 amino acids to create proteins; 9 are essential and must be obtained from the diet.

Protein Digestion and Absorption

Protein digestion begins in the stomach and continues in the small intestine. - Stomach: Pepsin and hydrochloric acid initiate digestion. - Small intestine: Amino acids are absorbed. - Cholecystokinin: Hormone stimulating release of proteases from the pancreas. - Hydrochloric acid: Converts pepsinogen to pepsin. Example: Protein digestion relies on both pepsin and hydrochloric acid.

Protein Requirements and Health

Adequate protein intake is crucial for health and metabolism. - Recommended intake: 10-35% of calories should come from proteins. - Calories: Proteins provide 4 calories per gram. - Limiting amino acid: An amino acid in short supply restricts protein synthesis. - Conditionally essential amino acids: Become essential during illness. - Wasted amino acids: Converted into calories if not used for protein synthesis. Example: Eating too little protein affects digestion, absorption, immunity, and energy malnutrition.

Nitrogen Balance

Nitrogen balance reflects protein metabolism. - Positive nitrogen balance: Occurs during pregnancy, growth, or recovery.

Water and Minerals

Water: Properties and Functions

Water is the most abundant nutrient in the body and is vital for physiological processes. - Universal solvent: Due to polar charges, water dissolves many substances. - Fluid compartments: Extracellular fluid is outside cells; water moves toward higher solute concentrations. - Consumption: Water is consumed when amino acids split apart, not created. - Dehydration: Reduces ability to maintain body temperature. - Edema: Accumulation of fluid in tissues. Example: Water is not gained through skin; dehydration impairs thermoregulation.

Minerals

Minerals are inorganic nutrients required for various bodily functions. - Cations: Positively charged ions.

Alcohol

Alcohol Metabolism and Effects

Alcohol is not a nutrient, though it provides calories. - Standard drink: 12 oz beer, 5 oz wine, 1.5 oz shot. - Calories: Alcohol provides 7 calories per gram. - Metabolism: Liver is primarily responsible; most alcohol absorbed in stomach and small intestine. - Blood alcohol levels: Influenced by gender, ethnicity, genetics. - Proof: Proof is double the percentage of alcohol (e.g., 40% alcohol = 80 proof). Example: Alcoholic beverages contain ethanol.

Health Effects of Alcohol

Alcohol has both potential benefits and risks. - Potential benefits: Reduced risk of diabetes and cardiovascular disease. - Long-term effects: Impaired absorption of water, interference with digestion, decreased enzyme production, thiamin deficiency, Wernicke-Korsakoff Syndrome. - Alcohol and pregnancy: Pregnant individuals should avoid alcohol due to negative health impacts.

Carbohydrates

Types and Functions

Carbohydrates are a primary energy source and are classified as simple or complex. - Simple carbohydrates: Monosaccharides and disaccharides (e.g., sucrose, maltose, lactose). - Complex carbohydrates: Disaccharides and polysaccharides; long chains of sugar units. - Glycogen: Stored in liver and muscles; converted to glucose when blood sugar is low. - Starch: Chemical digestion begins in the mouth (amylase). Example: Sucrose is table sugar; muscle glycogen provides energy.

Carbohydrate Digestion and Regulation

- Enzymes: Amylase (salivary enzyme), pancreas regulates blood sugar. - Hormones: Insulin decreases blood glucose and increases stored glycogen; glucagon increases blood sugar.

Health Implications

- Dental caries: Caused by excess carbs. - Fiber: Reduces risk for diabetes, constipation, cardiovascular disease; insoluble fiber prevents diverticulitis.

Lipids

Types and Functions

Lipids are a diverse group of molecules, including triglycerides, phospholipids, and sterols. - Triglycerides: Most common lipid in body and food. - Sterols: Cholesterol is the best-known sterol. - Phospholipids: Start lipid transport process. - Calories: Lipids provide 9 calories per gram. Example: Chylomicrons are created by intestinal lining cells for lipid transport.

Health Implications

- Saturated fats: Affect VLDL the most; recommended maximum is 10% of calories. - Polyunsaturated fats: Best kind; go rancid quickly. - LDL: Not considered 'good' cholesterol. - Atherosclerosis: Caused by fatty buildup in blood vessels.

Vitamins

Vitamin Classification and Functions

Vitamins are organic compounds essential for health, classified as water-soluble or fat-soluble. - Water-soluble: B vitamins, vitamin C; absorbed in small intestine, often attached to proteins. - Fat-soluble: Vitamins A, D, E, K; stored in body fat. - Functions: Support vision, skin, bones, teeth, energy metabolism, blood clotting, and immune function. Example: Vitamin C prevents scurvy; vitamin D supports bone health.

Vitamin Deficiency and Overdose

Deficiency and overdose of vitamins can lead to specific diseases and symptoms.

Vitamin	Solubility	Deficient Disease	Overdose Disease
Vitamin A	Fat	Night Blindness, Hyperkeratosis, keratomalacia	Hypervitaminosis A
Vitamin B1	Water	Beriberi, Wernicke-Korsakoff Syndrome	Drowsiness
Vitamin B2	Water	Ariboflavinosis	Liver Damage
Vitamin B3	Water	Pellagra	Diarrhea, Nausea & heartburn
Vitamin B6	Water	Anemia, neuropathy	Nerve damage
Vitamin B7	Water	Dermatitis	None
Vitamin B9	Water	Megaloblastic anemia, neural tube defects	May mask symptoms of B12 deficiency
Vitamin B12	Water	Deficiency: Anemia, nerve damage	Acne-like rash
Vitamin C	Water	Scurvy	Vitamin C Megaloblastic
Vitamin D	Fat	Rickets & Osteomalacia	Hypervitaminosis D
Vitamin E	Fat	Mild hemolytic anemia	Increased risk of heart failure
Vitamin K	Fat	Anemia, diarrhea	Increased clotting in patients

Vitamin Sources and Uses

Vitamins are found in a variety of foods and serve distinct physiological roles.

Vitamin	What We Use It For	Good Sources
A	Healthy vision, skin, bones, teeth, reproduction	Liver, Egg, Fish, Milk, Carrots, Sweet Potato, Pumpkin, Spinach
B1	Convert food into energy, nerve function	Dairy, Meat, Whole Grains, Nuts, Veggies
B2	Convert food into energy, support healthy skin, hair, blood, brain	Dairy, Meat, Green Leafy Veggies
B3	Convert food into energy, essential for healthy nervous system	Beef, Chicken, Shrimp, Watermelon, Fish, Tomatoes, Avocado
B6	Make red blood cells, improve sleep, appetite, mood	Chicken, Fish, Banana, Watermelon, Potato
B7	Convert food to energy, break down glucose	Whole Grains, Egg, Grapes, Strawberries
B9	Cell creation, DNA synthesis	Legumes, Spinach, Pear, Grapes, Avocado
B12	Break down fatty acids, amino acids, make red blood cells, bones, teeth	Dairy, Beef, Pork, Fish
C	Antioxidant, immune system, helps heal wounds	Fruit & Veggies, Peppers, Broccoli, Tomatoes
D	Acts on calcium, helps bones & teeth	Egg, Fish, Dairy, Sunlight
E	Antioxidant, helps stabilize cell membranes	Peanut, Sunflower, Spinach, Broccoli
K	Blood clotting, bone health	Broccoli, Leafy Greens, Liver, Egg

Energy Balance and Nutrition

Energy Balance

Energy balance is the relationship between calories consumed and calories expended. - Proteins: 4 calories per gram. - Lipids: 9 calories per gram. - Alcohol: 7 calories per gram. Example: 104 calories in a drink with 8g alcohol and 12g carbs.

Food Safety and Regulation

Food Labels

Food labels list ingredients in order of weight and provide nutritional information.

Nutrition Across the Lifespan

Pregnancy and Infancy

Pregnant individuals have a positive nitrogen balance and require adequate nutrients for fetal development.

Additional Information

Phytochemicals

Phytochemicals are found in green foods and may provide health benefits.

Supplements

Supplements are most beneficial when taken during illness. ----------------------------------------