Water, Electrolytes, Vitamins, Minerals, and Antioxidants: Exam 3 Study Guide

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Water and Electrolytes

Intracellular and Extracellular Electrolytes

Electrolytes are minerals that carry an electric charge and are essential for various physiological functions. They are distributed in two main fluid compartments:

Intracellular Electrolytes: Found inside cells. The primary intracellular electrolytes are potassium (K+) and phosphate (PO43-).
Extracellular Electrolytes: Found outside cells, mainly in blood plasma and interstitial fluid. The main extracellular electrolytes are sodium (Na+) and chloride (Cl-).

Key Functions:

Regulate fluid balance between compartments via osmosis.
Enable nerve impulse transmission and muscle contraction.
Maintain acid-base balance.

Relationship Between Electrolyte Concentration, Water Movement, and Cell Result:

Water moves toward higher solute (electrolyte) concentration.
If extracellular fluid is hypertonic (higher solute), water leaves the cell, causing it to shrink.
If extracellular fluid is hypotonic (lower solute), water enters the cell, causing it to swell or burst.

Major Functions of Electrolytes

Sodium (Na+): Fluid balance, nerve transmission, muscle contraction.
Potassium (K+): Maintains cell integrity, nerve impulses, muscle contraction (especially heart).
Chloride (Cl-): Maintains fluid balance, part of stomach acid (HCl).
Phosphorus (P): Bone structure, energy metabolism (ATP), cell membranes.
Magnesium (Mg): Enzyme function, muscle contraction, bone health.

Factors Affecting Body Water Percentage

Age (decreases with age)
Gender (males usually have higher % due to more muscle mass)
Body composition (more muscle = more water; more fat = less water)

Functions of Water in the Body

Solvent for biochemical reactions
Transport of nutrients and waste
Temperature regulation (sweating)
Lubrication and cushioning of joints and organs

Dehydration, Heat Stroke, Heat Cramps, Heat Exhaustion

Dehydration: Excessive loss of body water, leading to impaired function.
Heat Cramps: Muscle spasms due to loss of electrolytes and fluids.
Heat Exhaustion: Heavy sweating, weakness, rapid pulse; body overheats but can still cool itself.
Heat Stroke: Life-threatening; body temperature rises above 40°C (104°F), sweating stops, confusion, possible unconsciousness.

Thirst Mechanism

Triggered by increased blood osmolality or decreased blood volume.
Regulated by the hypothalamus in the brain.

Maintaining Normal Blood Pressure Through Diet

Reduce sodium intake.
Increase potassium, calcium, and magnesium intake.
Follow the DASH diet (Dietary Approaches to Stop Hypertension).

High/Low Sodium Foods

High sodium: Processed foods, canned soups, deli meats, snack foods.
Low sodium: Fresh fruits and vegetables, unprocessed grains, fresh meats.

Vitamins and Minerals

Vitamin and Mineral Deficiencies

Calcium: Deficiency can cause osteoporosis, muscle spasms.
Magnesium: Deficiency may lead to muscle cramps, mental disorders.
Chloride: Rare, but can cause metabolic alkalosis.
Phosphorus: Deficiency is rare; can cause bone pain, muscle weakness.
Potassium: Deficiency (hypokalemia) can cause muscle weakness, arrhythmias.
Beta-carotene: Precursor to vitamin A; deficiency can cause vision problems.
Vitamin E: Deficiency can cause nerve and muscle damage.

Rich Food Sources

Nutrient	Rich Food Sources
Calcium	Dairy products, leafy greens, fortified foods
Magnesium	Nuts, whole grains, leafy greens
Chloride	Table salt, seaweed, tomatoes
Phosphorus	Meat, dairy, nuts, legumes
Potassium	Bananas, potatoes, beans, dairy
Beta-carotene	Carrots, sweet potatoes, spinach
Vitamin E	Nuts, seeds, vegetable oils

Food Sources and Synthesis in the Body

Some vitamins (e.g., vitamin D) can be synthesized in the body with sunlight exposure.
Most minerals must be obtained from the diet.

Relationship Between Vitamin D and Calcium

Vitamin D enhances intestinal absorption of calcium.
Deficiency in vitamin D can lead to poor calcium absorption and bone disorders (e.g., rickets, osteomalacia).

Osteoblasts vs Osteoclasts

Osteoblasts: Cells that build new bone tissue.
Osteoclasts: Cells that break down bone tissue.

Bone Development Process

Begins in fetal development and continues through adolescence.
Order: Bone formation (ossification) → bone growth → bone remodeling.

Hypercalcemia

Abnormally high blood calcium levels.
Can cause kidney stones, bone pain, muscle weakness, and impaired absorption of other minerals.

Neural Tube Defect

Birth defects of the brain, spine, or spinal cord (e.g., spina bifida).
Often related to folate deficiency during pregnancy.

Heme vs Non-Heme Iron

Heme iron: Found in animal products (meat, poultry, fish); better absorbed.
Non-heme iron: Found in plant foods (beans, lentils, spinach); less efficiently absorbed.

Antioxidants and Free Radicals

Antioxidants and Their Role

Antioxidants neutralize free radicals, preventing cellular damage.
Key antioxidant vitamins: Vitamin C, Vitamin E, beta-carotene.

Free Radicals

Unstable molecules with unpaired electrons.
Formed during normal metabolism, exposure to pollution, radiation, smoking.
Can damage DNA, proteins, cell membranes (oxidative stress).
Associated with aging, cancer, cardiovascular disease.

Risk Factors and Issues Associated with Free Radicals

Smoking, pollution, UV exposure, poor diet increase free radical production.
Antioxidant-rich diets can help reduce risk.

What Can Increase or Decrease Cancer Risk?

Increase: Smoking, high red/processed meat intake, low fruit/vegetable intake, obesity, alcohol.
Decrease: High intake of fruits, vegetables, whole grains, regular physical activity.

Vitamins: Functions and Deficiencies

Vitamin C Functions and Deficiency Risk

Collagen synthesis, antioxidant, enhances iron absorption, immune function.
Deficiency (scurvy) risk: smokers, elderly, people with limited diets.

Antioxidant Vitamins

Vitamin C, Vitamin E, beta-carotene (pro-vitamin A).

Pro-vitamin

A substance that can be converted into a vitamin in the body (e.g., beta-carotene to vitamin A).

Mineral	Main Function	Deficiency Symptoms
Calcium	Bone/teeth health, muscle contraction	Osteoporosis, muscle spasms
Magnesium	Enzyme function, muscle/nerve function	Muscle cramps, mental disorders
Potassium	Fluid balance, nerve/muscle function	Muscle weakness, arrhythmias
Phosphorus	Bone/teeth, energy metabolism	Bone pain, muscle weakness
Chloride	Fluid balance, stomach acid	Metabolic alkalosis