Carbohydrates and Proteins Overview

Study Notes

Carbohydrates are a crucial energy source.
Simple carbohydrates include monosaccharides (glucose, fructose) and disaccharides (sucrose, lactose).
Simple carbs are quickly absorbed, causing rapid blood sugar spikes, lacking in nutrients.
Complex carbohydrates include polysaccharides (starch, glycogen).
Complex carbs offer sustained energy and dietary fiber aiding digestion and stabilizing blood sugar.
Carbohydrate digestion starts in the mouth with salivary amylase.
Enzymes in the small intestine (lactase, sucrase) further break down carbs into monosaccharides.
Glucose is stored as glycogen in the liver and muscles, entering metabolic pathways for ATP production.
Fiber, soluble (pectin) and insoluble (cellulose), promotes satiety, regulates blood sugar, and lowers cholesterol.
Recommended daily fiber intake: 25-35 grams.

Proteins are crucial for body structure and function.
Proteins are broken down into amino acids.
Essential amino acids must be consumed through diet; nonessential ones are synthesized by the body.
Proteins are denatured in the stomach by pepsin, then further broken into peptides and amino acids in the small intestine.
Amino acids are used to synthesize body proteins, enzymes, and hormones.
During energy shortages, amino acids can be used for gluconeogenesis or ketogenesis.
Amino acid metabolism involves deamination and transamination.
Deamination removes amino groups; transamination transfers amino groups.
The carbon skeletons are used in various metabolic pathways.

Fats are concentrated energy storage and structural components.
Triglycerides are the primary stored fat.
Phospholipids are cell membrane components.
Cholesterol contributes to steroid hormone synthesis.
Saturated fats (no double bonds) are primarily found in animal products, while unsaturated fats (one or more double bonds) are found in plant sources.
Bile emulsifies fats, allowing pancreatic lipase to break down triglycerides into fatty acids and monoglycerides.
Absorbed fats are packaged into chylomicrons for transport through the lymphatic system.
Fat metabolism produces ketones during prolonged fasting or low-carbohydrate intake.
Fats require carbohydrate metabolism intermediates for full oxidation in the TCA cycle.

Vitamins are essential organic molecules that mainly act as coenzymes.
B-complex vitamins are crucial for energy production and metabolism. (e.g., Thiamin supports glucose metabolism).
Vitamin C is an antioxidant, supporting immune health and skin elasticity.
Vitamin A is vital for vision.
Vitamin D regulates calcium absorption and bone health.
Vitamin E is an antioxidant, protecting cells from free-radical damage.
Vitamin K is crucial for blood clotting and bone health.

Minerals are inorganic elements vital for various functions.
Calcium and phosphorus are vital for bone health, regulated by hormones and Vitamin D.
Sodium and potassium are essential for fluid balance, nerve transmission, and muscle function.
Iron is required for oxygen transport, with absorption regulated by hepcidin.
Zinc supports immune function and cellular repair.
Iodine is required for thyroid hormone synthesis and metabolism regulation.
Magnesium is important for ATP production, nerve function, and blood sugar regulation.