HS 251 - Major Minerals

What are the major minerals? (7)

• Sodium

• Chloride

• Potassium

• Calcium

• Phosphorus

• Magnesium

• Sulfate

Sodium (Na+): Key Factors (2)

• Cation found in blood & interstitial fluid

• Enters circulation & eventually filtered by kidneys, excreted in urine

What are the food-based forms of sodium (4)

1. Table salt (NaCl)

2. Sodium phosphate

3. Baking soda (sodium bicarbonate)

4. MSG (monosodium glutamate)

What are sodium-chloride bonds broken by?

Stomach acid

Sodium bioavailability

Highly bioavailable: bodies are incredibly efficient for taking it in as nutrients

Why is sodium important? (4)

• Fluid Balance

• Transmit nerve impulses: signal conduction

• Muscle contrations

• Nutrient transport

Sodium & Fluid Balance

changes solute concentration that affects fluid volume of cells

What does higher Na+ in blood mean?

increases blood osmolarity → thirst → release ADH from pituitary gland

Sodium & Nutrient Transport

Sodium-dependent glucose transport proteins in enterocytes & renal cells

What does the renin-angiotensin-aldosterone system regulate?

blood volume, blood pressure, sodium balance related

Antidiuretic hormone

regulates water excretion

When sodium levels drop…

renin (kidneys) → angiotensinogen → angiotensin I → angiotensin II

• stimulates secretion of aldosterone — causes kidneys to increase sodium reabsorption

Hyponatremia

too-low levels of sodium in blood

Causes of Hyponatremia (7)

• Excess of water relative to solute

  • Too much water/fluid consumed (e.g., water intoxication)

  • Impaired renal free water excretion

  • Excess antidiuretic hormone activity

• Loss of sodium

  • Vomiting, diarrhea, sweat

  • Diuretics

Regulate high sodium levels (2)

• angiotensin II & aldosterone levels decrease

• kidneys increase sodium excretion in urine

Pathway of high sodium levels messaging

Hypothalamus → pituitary → ADH → H2o resorption

What does increased fluid retention contribute to?

increased blood volume (diluting high Na solute concentration) → high blood pressure

How does high sodium lead to vascular changes?

reduced blood vessel dilation (narrower)

Minimum Sodium need

180 mg (~1/16th teaspoon)

DRI/AI for Sodium

1500 mg/day (~3/4 teaspoon) → more realistic & accommodations increased Na+ needs for moderate activity

Current average Sodium consumption

3,400 mg/day

Food sources of Sodium (%)

• >75% - processed foods (canned foods, cured meat, frozen meals, sauces)

• ~12% - naturally occuring sodium (seaweed)

• ~5% - salt added during cooking

• ~5% - salt shaked/seasoning @ table

What health issues is high sodium intake linked to?

Risk of hypertension (high BP)

Tolerable UL for Salt

2,300 mg/day (~1 tsp)

What does high blood pressure increase risk of?

Heart disease - stroke, renal disease

Chloride (CI-) Key Components

• Anion

• Part of sodium chloride

Functions of Chloride (2)

• Role as anion in fluid balance & pH balance

• component of HCl in Stomach

DRI is AI for Chloride

2,300 mg/day

Chloride: Food Sources

• Table Salt (40% sodium, 60% chloride)

• Potassium Chloride: main salt substitute

• Plant-based foods naturally (tomatoes, lettuce, celery)

Is Toxicity & hypochloremia rare or common in chloride?

Rare

• Toxicity: stems from significant dehydration, sweating

• Hypochloremia: losses from vomiting, diarrhea

What are symptoms of toxicity & hypochloremia?

• Shallow breathing

• Muscle weakenss

• muscle spasms

• Twitching

Potassium (K+) Key Factors (3)

• Major cation of intracellular fluid (ICF)

• Enters circulation, and most taken up by cells

• Excess excreted via kidneys in urine

Potassium bioavailability

Highly (~85%) absorbed in small intestine & colon

How is potassium tightly regulated (low vs. high levels)?

• Low: kidneys reabsorb more

• High: aldosterone is stimulated → K+ excretion & Na+ reabsorption

Potassium Functions (5)

• Key role in electrical function of cells

• Conducts electrical impulses (maintains regular heartbeat)

• Skeletal & smooth muscle contraction

• Fluid balance (sodium-potassium pump)

• pH balance

High potassium levels associated with

Lower BP

Increasing sodium excretion via kidneys lowers…

BP