digestive system

Digestive System

Macromolecules

• Carbohydrates– Preferential metabolism• Complex

Starch from grains and vegetables• Simple

Mono (fruits) & Disaccharides (sugar, dairy)• Cellulose (structural polysaccharide)

roughage

ATP!

Atkins• Not enough Carbs

(note: brain cannot metabolize fatty acids –albumin! BBB)

• Body starts burning fatty acids• Produces ketones (acidic)• Lowers pH • Low insulin= ketoacidosis/ diabetic coma

(medical emergency)– Nauseau, vomiting, dehydration, LOC

Lipids• Energy Source/ Cell membranes– Fats• Triglycerides (most common)• Stored (adipose)

• Phospholipids• Cholesterol• Metabolized:

Triglycerides –(duodenum)Fatty acids + Glycerol

Saturated UnsaturatedAnimalsFatty Plants

SeedsNutsOils (plants)

Fats/ Lipids• Free Fatty acids

•Glycerols

•Combine to form Triglycerides

Cholesterol

• Only from animal sources• Needed in cell functions– Body produces approx. 100 mg/day– Consumption should be < 200 mg/day

• Good vs. Bad Cholesterol– HDL pick up fatty acids from around body– LDL and VLDL stick to arteries around body

Fats needed for…

• Energy Storage• Absorption of vitamins (A, D, E, K)

• Stored directly after consumption

*

Digestion of Fats into intestines

Protein

• needed for– Enzymes!– muscle– immune system

– As last resort….ketosis for higher priority muscles

Sources

• Meat• Fish • Dairy

Amino Acids•20 amino acids total

• 9 essential amino acids

• 11 non essential amino acids

When broken down…

• Ketosis (only when no carbs)– energy production when no energy from glucose

for brain, heart, etc.• protein synthesis for muscles & liver• Energy for muscles, kidney, & adipose

• ↑ insulin, testosterone → ↑ protein synthesis

Calorie:

• Unit of Energy• By Definition:– Amount of heat required to raise temperature of

1 gram of water by 1 degree celsius

LOOKING AT CALORIES:

• Proteins= 4 calories/ gram• Carbohydrates= 4 calories/ gram

• fat= 9 calories/ gram– So much more efficient storage!

Finding %:

• Can take grams and divide by total grams to find % in food item

• Ideal % for intake:– 30% carbohydrates– 40% proteins– 30% fat

Diet• one-third of children and more than two-thirds of

adults in the United States are overweight or obese

• What is a "Healthy Diet"?The Dietary Guidelines describe a healthy diet as one that

– Emphasizes fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products

– Includes lean meats, poultry, fish, beans, eggs, and nuts; and

– Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.

Dietary guidelines:

• Enjoy your food, but eat less. • Avoid oversized portions. • Make half your plate fruits and vegetables. • Switch to fat-free or low-fat (1%) milk. • Compare sodium in foods like soup, bread, and

frozen meals – and choose the foods with lower numbers.

• Drink water instead of sugary drinks.

BMR

• Rate body expends energy at rest• Affected by:– Sex– Temperature– Size– Hormone activity

BMI

• Measure of body fat based on a height/ weight ratio

• Inaccurately used in medical field• Limitations:– Athletes– Age– elderly

Food Pyramid

• Designed as a guide to determine how much of certain foods should be consumed

• Move away from standard 2000 cal diet but suggests government guidelines of recommended allowances

Vitamins• Organic• Classified by solubility

Vitamins

• A: production of visual pigments• D: skin, promote Ca/ P absorption (bone

growth/ remodeling)• E: antioxidants• K: (prothrombin) blood clotting• B: metabolism of proteins, lipids, & carbs• C: collagen; metabolize AA, Fe absorption

Minerals

• Ca; P: bones & teeth• Fe: blood• CaPO4- bones• Na, Cl, K- Blood