Carbohydrates and Their Functions

Study Notes

Carbohydrates

Main energy source for the brain: Glucose
Fiber recommendation: 25-38 grams per day. Most Americans do not meet this recommendation.
Parts of a whole grain: Bran, endosperm, and germ
Glycemic index: A measure of how quickly a food raises blood glucose levels. Higher glycemic index foods cause a faster and larger spike in blood sugar.
Diverticulosis: Small pouches that form in the colon. A high-fiber diet can help prevent diverticulosis.
Monosaccharides: Simple sugars; glucose, fructose.
Disaccharides: Sugars composed of two monosaccharides; lactose, maltose, sucrose.
Number one source of added sugar in the average American diet: Soda.
Sugar substitutes: Aspartame, saccharin, sucralose.
Enzyme that breaks down starch into maltose in the small intestine: Pancreatic amylase.
Hormones that balance blood sugar levels:
- Insulin: Lowers blood sugar levels by promoting glucose uptake into cells.
- Glucagon: Raises blood sugar levels by stimulating the release of glucose from the liver.
Diabetes symptoms: Skin dryness, sudden vision changes, thirst, unintentional weight loss, slow wound recovery, shakiness.
Outcomes of uncontrolled blood sugar levels: Organ damage, cardiovascular disease, damage to epithelial cells, potential coma.
How to prevent type 2 diabetes: Regular exercise, a balanced diet, avoiding alcohol, walking after meals, maintaining a healthy weight.
Carbs fuel physical activity.

Fats

Primary fat in our diet: Triglycerides- made up of one glycerol molecule and three fatty acids.
Healthy dietary fats: Unsaturated fats (monounsaturated and polyunsaturated).
Unhealthy dietary fats: Trans fats and saturated fats.
Saturation in fats: Refers to the number of hydrogen atoms attached to the carbon chain. Saturated fats have all available hydrogen atoms, while unsaturated fats have double bonds between carbon atoms which allows for further hydrogen addition.
Sources of saturated and unsaturated fats:
- Saturated: Butter, coconut oil, red meat.
- Unsaturated: Fish, olive oil.
Types of fats that lead to heart disease: Saturated fats.
Phospholipids: A type of fat with a glycerol backbone, two fatty acids, and a phosphate group.
Functions of fats:
- Transport and absorption of fat-soluble vitamins.
- Insulation.
- Component of cell membranes.
- Storage for energy.
Triglycerides uses in the body:
- Stored for energy.
- Provide energy.
- Synthesis of lipid-containing compounds.
Good and bad cholesterol:
- VLDL: Very low-density lipoprotein.
- LDL: Low-density lipoprotein; considered "bad" cholesterol.
- HDL: High-density lipoprotein; considered "good" cholesterol.
**Cholesterol is made in the body. **
Essential fatty acids (Omega-3 and 6) must be obtained from the diet.
Types of vegetarian diets:
- Lacto-ovo: Includes dairy and eggs.
- Pesce: Includes fish, dairy, and eggs.
- Vegan: Excludes all animal products.

Proteins

Energy density for carbs/fats/proteins:
- Carbs: 4 kcal/gram.
- Fats: 9 kcal/gram.
- Proteins: 4 kcal/gram.
Gluconeogenesis: The process of creating glucose from non-carbohydrate sources, such as amino acids.
Amino acid structure: Composed of an amine group, a carboxyl group, a side chain, and a central carbon atom.
Enzyme that breaks down proteins in the small intestine: Protease.
Transamination: Transfer of an amine group from one amino acid to another to create a new amino acid.
Health problems associated with high and low protein intake:
- High: High cholesterol, kidney disease, increased urea production.
- Low: Edema.
Immune health and protein: Antibodies are proteins.
Functions of protein in the body:
- Build and maintain tissue.
- Hormone synthesis.
- Maintain fluid balance.
Complete vs. incomplete proteins:
- Complete: Contain all essential amino acids; Meat, poultry, fish, eggs, dairy.
- Incomplete: Lack one or more essential amino acids; Plant-based proteins.
- Complete plant-based proteins: Soy, tofu.
Complementary plant-based protein sources: Peanut butter and bread, beans and rice, barley and lentils.
Protein digestion and absorption: Absorption occurs in the small intestine.