Carbohydrates Used as energy source in the body Some can be stored as glycogen (a storage polymer) in the liver and muscles and quickly converted back to glucose Excess is converted by the body to be stored as fat

Carbohydrates Glycemic index: a measure of how quickly a carbohydrate is digested and glucose is absorbed from the small intestine to the bloodstream. The higher the GI, the quicker the release of glucose.

Carbohydrates Carbohydrates with a low GI (55 or less) don't make our blood glucose levels rise very high for very long. They provide sustained energy. Carbohydrates with a high GI (70 or more) are the ones that cause our blood glucose levels to go higher for longer. High blood glucose may cause damage to vital organs.

Carbohydrates Simple carbohydrates: ○ Quick to break down – sugar released quickly ○ High glycemic index ○ E.g. potatoes, white flour Complex carbohydrates: ○ Slower to break down – sugar is released slowly ○ Lower glycemic index ○ E.g. whole grains, oats, beans

Proteins Used to build enzymes, muscle tissue, plasma proteins, hormones Excess cannot be stored and is converted to fat with nitrogenous waste begin disposed of in urine Eight essential amino acids (body cannot make, must be consumed in diet) 20 amino acids total High protein foods include: meat, beans, dairy, eggs, nuts

Lipids Used as high energy source Include fats, oils, and cholesterol Serve as high energy source: each gram of a lipid contains 2.5 times more calories than a gram of protein or carbohydrate Essential fatty acids ○ Fatty acids the body can’t make must be in diet

Lipids  Two general categories of fatty acids: Unsaturated fatty acids ○ Liquid at room temp. ○ Oils, plant fats (generally) Saturated fatty acids ○ Solid at room temp. ○ Butter, animal fats (generally)

Lipids  Types and Functions of Lipids Triglycerides ○ crucial in the body for energy storage Steroids ○ benefit the body by helping determine and control the structure of plasma membrane

Lipids Phospholipids ○ key role in constituting cell membranes. Glycolipids ○ play an important role in boosting the body’s immune system Lipoproteins (cholesterols) ○ help fat move around the body in the bloodstream ○ exist in the form of Low Density Lipoprotein (HDL) and High Density Lipoprotein (LDL)

Vitamins Are organic compounds (other than carbs, lipids or proteins) that the body needs for metabolic processes, but is unable to produce in adequate quantities on its own Some vitamins are fat soluble, such as Vitamins A, D, E, and K

Vitamins Others are water soluble, such as Vitamin C ○ need to take these with food b/c body can’t absorb them otherwise and they may make you feel ill. Too little or too much of a vitamin can have harmful effects. ○ E.g. too little Vitamin D causes Rickets, bone decalcification and weakening (osteoporosis), but too much can cause calcification of soft tissues, diarrhea, possible renal (kidney) damage

Dietary Supplements  Dietary Supplements Are nutrients and plant products used to enhance health Ironic fact: most people who take supplements don’t need them. Why might that be?

Minerals Are non-organic compounds that the body needs to function properly. Examples: calcium, potassium, sodium

Minerals ○ Calcium Function: strong bones, teeth, nerve conduction, muscle contraction Food sources: dairy, leafy green vegetables Too little: stunted growth in children, low bone density in adults Too much: kidney stones, interferes with iron and zinc absorption

Minerals ○ Potassium Function: Food sources: Too little: Too much: ○ Sodium Function: Food sources: Too little: Too much:  (Use text p.273 to complete)

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