Nutrition 315 - Lecture 4 - 5

factors that make food organic

biological pest management
manure application
composting
crop rotations to maintain healthy soil, water, crops, and animals
no antibiotics, no hormones, fewer pesticides, genetic engineering, irradiation

biological pest management

using natural methods like predatory insects or traps to control pest instead of synthetic chemicals

composting

a natural process where organic matter such as food scraps and yard waste is broken down by microorganisms into a nutrient-rich soil amendment

concerns of genetically modified foods

new allergens or toxins
crossed species lines
resistance to herbicides and pesticides
loss of genetic diversity
trade barriers

food irradiation

food safety process that involves exposing food to a controlled amount of ionizing radiation

nanotechnology

study of controlling matter at the atomic or molecular level

nanoparticles used for

brightening food, keeping food fresh, decreasing fat content, and increasing vitamin bioavailability

salmonella

group of bacteria that causes one of the most common types of food borne illnesses

sources of salmonella

raw poultry, eggs, and unpasteurized milk

symptoms of salmonella

diarrhea, fever, abdominal cramps, nausea, and vomiting

norovirus

highly contagious virus that is leading cause of vomiting and diarrhea from foodborne illness
commonly referred to as the stomach flu

campylobacter

one of the most common causes of diarrheal illness in the US

sources of campylobacter

raw or undercooked poultry and untreated water

symptoms of campylobacter

diarrhea (often bloody), fever, watery diarrhea, ands stomach pain

campylobacter caused by...

bacteria typically found in the intestines of birds

e coli

bacteria that can produce a powerful toxin called shiva toxin

source of e coli

undercooked ground beef, raw produce, contaminated water

symptoms of e coli

severe body cramps, bloody diarrhea, and vomiting

e coli caused by…

ingesting bacteria that cause an infection in the lining of the intestine

listeria

a hardy bacterium that can grow even in cold temperatures like a refrigerator

sources of listeria

deli meats, hot dogs, and unpasteurized dairy products

symptoms of listeria

fever, muscle aches, and sometimes stiff neck or confusion

listeria caused by…

consuming food contaminated with listeria monocytogenes

mouth and salivary gland digestive functions

prep food for swallowing
detect taste molecules
start digestion of starch with amylase enzyme
start digestion of fat with lingual lipase

esophagus digestive function

moves food to stomach by peristaltic waves initiated by swallowing

stomach digestive functions

recreates gastric juice containing acid, enzymes, and hormones
creates chyme
secretes intrinsic factor
releases chyme to small intestine

intrinsic factor

a protein required fro vitamin B12 absorption

chyme

food mixed with gastric juice

liver digestive functions

produces bile to aid fat digestion and absorption

gallbladder digestive functions

stored concentrates bile and releases it to the small intestine

pancreas digestive functions

secretes pancreatic juice containing digestive enzymes and bicarbonate into the small intestine

small intestine digestive functions

mixes chyme with bile and pancreatic juice to complete digestion
secretes hormones and digestive enzymes to help regulate digestive processes
absorbs nutrients and other compounds in foods
transports remaining residue to large intestine

large intestine (colon) digestive functions

absorbs water and electrolytes
forms and stores feces
house most of the gut microbiota

sphincters through the digestive tract

lower esophageal sphincter → pyloric sphincter → hepatopancreatic sphincter → ileocecal valve → anal sphincters

amylase

digestive enzyme that breaks down carbs

lipase

digestive enzyme that breaks down fat

protase

digestive enzyme that breaks down protein

bicarbonate

produced in the pancreas and sm. intestine
neutralizes stomach acid when it reaches small intestine

stage 1 of enzyme action

process begins with a substrate like sucrose

stage 2 of enzyme action

substrate binds to the active site of the specific enzyme

stage 3 of enzyme action

hydrolysis

hydrolysis

breaking down complex molecules with the addition of water

stage 4 of enzyme action

individual products are released into the body for absorption, and the enzyme remains unchanged, free to repeat the process with a new molecule

epiglottis

prevents food from entering the trachea

gastrin

hormone that controls the release of HCl and pepsinogen

3 sections of the small intestine

duodenum, jejunum, and ileum

duodenum

first and shortest segment of the small intestine where food is neutralized and mixed with enzymes to be broken down

jejunum

middle section of the small intestine between the duodenum and ileum
primarily responsible for absorption of nutrients into the bloodstream

ileum

final and longest segment of the small intestine
plays a crucial role in finishing the absorption process before passing waste into the large intestine

digestion from stomach → small intestine

stomach → pyloric sphincter → duodenum → jejunum → illeum

bile pathway

liver → ducts from liver → gallbladder → common bile duct → pancreatic duct (junction) → hematopancreatic sphincter → duodenum

heartburn

painful burning sensation in the chest caused by stomach acid backing up into the esophagus

gastroesophageal reflux disease (GERD)

more chronic severe form of heartburn that can damage the esophageal lining

ulcers

painful sores in the lining of the stomach or duodenum

nonalcoholic fatty liver disease

condition where excess fat builds up in the liver of people who drink to little to no alcohol

gallstones

hardened deposits of digestive fluid that can form in the gallbladder
block the common bile duct

food intolerances

occurs when the body lacks a specific enzyme to perform hydrolysis on a certain food component

irritable bowel syndrome (IBS)

common functional disorder that affects the large intestine, causing cramping, abdominal pain, bloating, gas, and diarrhea or constipation

inflammatory bowel disease (IBD)

chronic inflammation and damage to the digestive tract
more severe conditions like Crohn’s disease and ulcerative colitis

hemorrhoids

swollen veins in the lowest part of the rectum and anus
caused by straining during bowel movements or chronic constipation