NUTRITION AI 3

Water

Most essential nutrient; makes up ~60–70% of body; absence is fatal within days

Functions of Water

Solvent, transport nutrients/waste, temperature regulation, lubrication, chemical reactions

Electrolytes

Substances that dissolve in water into ions; essential for fluid balance and nerve function

Cation

Positively charged ion (Na+, K+)

Anion

Negatively charged ion (Cl

Intracellular Fluid

Fluid inside cells; ~2/3 of total body water

Extracellular Fluid

Fluid outside cells; includes interstitial fluid and blood plasma

Osmoregulation

Regulation of water balance via osmosis and electrolyte control

Insensible Water Loss

Unnoticed loss through breathing and skin (~900 mL/day)

Sensible Water Loss

Noticeable loss via urine (~1500 mL) and feces (~100 mL)

Vitamins

Organic micronutrients needed in small amounts; do not provide energy but regulate body processes

Fat

Soluble Vitamins

Water

Soluble Vitamins

Bioavailability (Vitamins)

Amount absorbed and used; affected by diet composition and fat intake

Coenzymes

Vitamins (especially B vitamins) that assist enzymes in energy metabolism

Vitamin A

Needed for vision (rhodopsin), immune function, cell growth and differentiation

Night Blindness

Early symptom of vitamin A deficiency due to lack of rhodopsin

Xerophthalmia

Severe vitamin A deficiency causing dry eyes and possible blindness

Antioxidants

Compounds (vitamins A, C, E) that neutralize free radicals and prevent cell damage

Vitamin Toxicity

Usually from excess supplements; especially dangerous with fat

Minerals

Inorganic nutrients required for structure and regulation; do not provide energy

Major Minerals

Needed in >100 mg/day; include calcium, sodium, potassium, phosphorus, magnesium

Trace Minerals

Needed in <100 mg/day; include iron, zinc, iodine, selenium, copper

Bioavailability (Minerals)

Degree minerals are absorbed; affected by diet, pH, and interactions

Calcium

99% stored in bones; needed for muscle contraction, nerve signaling, blood clotting

Sodium

Main extracellular cation; regulates fluid balance, nerve impulses, blood pressure

Potassium

Main intracellular cation; supports heart function, fluid balance, muscle contraction

Chloride

Major extracellular anion; part of HCl in stomach; helps digestion and fluid balance

Phosphorus

Bone formation and energy metabolism (ATP)

Magnesium

Cofactor for enzymes; involved in muscle and nerve function

Sulfur

Component of amino acids and proteins; involved in acid

Iron

Most abundant trace mineral; essential for oxygen transport and energy metabolism

Hemoglobin

Protein in red blood cells that carries oxygen using iron

Myoglobin

Oxygen

Heme Iron

Found in animal foods; highly bioavailable and easily absorbed

Nonheme Iron

Found in plant foods; less bioavailable and affected by diet factors

Iron Absorption Enhancers

Vitamin C, stomach acid, animal protein

Iron Absorption Inhibitors

Calcium, phytates, fiber, tannins

Iron Deficiency

Leads to iron

Iron Recycling

Body reuses iron from old red blood cells to make new ones

Zinc

Important for immune function, wound healing, growth, and enzyme activity

Iodine

Required for thyroid hormones that regulate metabolism

Fluoride

Strengthens teeth and prevents cavities

Selenium

Antioxidant; part of glutathione peroxidase enzyme

Copper

Helps iron metabolism and formation of red blood cells

Foodborne Illness

Illness caused by consuming contaminated food or beverages

Pathogen

Disease

Infection

Illness caused by ingestion of live pathogens that grow in the body

Intoxication

Illness caused by toxins produced by microorganisms in food

Food Danger Zone

40°F–140°F; optimal bacterial growth occurs between 60–110°F

Time Rule

Food left in danger zone >2 hours increases risk of illness

High

Risk Groups

Common Symptoms

Nausea, vomiting, diarrhea, abdominal pain, fever

Salmonella

Found in raw poultry, eggs; symptoms: fever, diarrhea, cramps (12–72 hrs)

E. coli O157:H7

Found in undercooked ground beef; causes severe/bloody diarrhea, kidney damage

Listeria monocytogenes

Found in unpasteurized dairy, deli meats; dangerous in pregnancy

Clostridium botulinum

Produces toxin in improperly canned foods; causes paralysis, can be fatal

Campylobacter jejuni

Found in raw meat, water; causes diarrhea, fever, cramps

Staphylococcus aureus

From poor hygiene; toxins cause rapid vomiting (30 min–8 hrs)

Food Contamination Sources

Humans, animal feces, water, soil, air, poor handling, improper storage

Food Safety Practices

Cook thoroughly, refrigerate promptly, avoid cross

Pasteurization

Heat treatment to kill harmful microorganisms in foods

Food Irradiation

Radiation used to destroy pathogens and extend shelf life

Microbial Growth Conditions

Warm temperature, moisture, oxygen, neutral pH, nutrients

High

Protein Foods Risk