The Micronutrients and Water Part 3 Chapter 2

Electrolytes  Electrically charged particles dissolved in body fluids Sodium (Na + ) Potassium (K + ) Chlorine (Cl - )

Sodium  Roles in body  Modulate fluid exchange within the body's fluid compartments

Fig. 12-6, p. 405 ABABAB With equal numbers of solute particles on both sides of the semipermeable membrane, the concentrations are equal, and the tendency of water to move in either direction is about the same. Now additional solute is added to side B. Solute cannot flow across the divider (in the case of a cell, its membrane). Water can flow both ways across the divider, but has a greater tendency to move from side A to side B, where there is a greater concentration of solute. The volume of water becomes greater on side B, and the concentrations on side A and B become equal. Stepped Art

Sodium  Roles in body  Regulate the acid and base qualities of body fluids NaHCO 3

Sodium  Roles in body  Establish the proper electrical gradient across cell membranes

Sodium Sodium Roles in the Body  Assists in nerve impulse transmission Action potential  Assists in muscle contraction Action potential

Sodium Dietary recommendations  Moderate intake of salt and sodium.  Excesses may aggravate hypertension 4500 mg – typical Western diet

Sodium Sodium in Foods  Processed foods (75% of dietary sodium)  Table salt (15% of dietary sodium)  Moderate amounts in meats, milks, breads and vegetables (10% of dietary sodium)

Sodium Sodium and Hypertension  Salt can have a great impact on high blood pressure. Restriction does help to lower BP. Salt sensitivity - BP dependent on sodium intake.  Dietary Approaches to Stop Hypertension (DASH) dietary plan to lower BP  Sodium and Bone Loss (Osteoporosis) High sodium intake linked to calcium excretion.

Sodium Sodium Recommendations  Minimum Adults: 500 mg/day  Adequate Intake (2004) For those years of age, 1,500 mg/day For those years of age, 1,300 mg/day For those older than 70 years of age, 1,200 mg/day  The upper intake level for adults is 2,300 mg/day.  Maximum % Daily Value on food labels is set at 2400 mg/day.

Sodium Deficiency  After vomiting, diarrhea, heavy sweating.  Symptoms are muscle cramps, mental apathy, and loss of appetite.  Salt tablets without water induce dehydration.

Sodium Be careful of hyponatremia during ultra-endurance athletic activities Conservation  Kidneys – aldosterone

Chloride Chloride Roles in the Body  Maintains normal fluid and electrolyte balance  Part of hydrochloric acid found in the stomach Necessary for proper digestion

Chloride Essential nutrient in fluid balance.  Extracellular anion (Cl - ) It is associated with sodium  Rises and falls with sodium levels  Regulated (indirectly) by aldosterone (sodium)

Chloride Chloride Recommendations and Intakes  Recommendations Adequate Intake (2004)  For those years of age, 2,300 mg/day  For those years of age, 2,000 mg/day  For those older than 70 years of age, 1,800 mg/day Upper intake level is 3,600 mg/day

Chloride Chloride Deficiency  Deficiency is rare (sodium)  Losses: Vomiting, Diarrhea or Heavy sweating.

Potassium An electrolyte associated with fluid balance. Associated with hypertension. It is found in fresh foods—mostly fruits and vegetables.

Potassium Potassium Roles in the Body  Maintains normal fluid and electrolyte balance  Assists in nerve impulse transmission and muscle contractions

Potassium Potassium Recommendations and Intakes  Adequate Intake (2004) For all adults, 4,700 mg/day  Fresh foods are rich sources.  Processed foods have less potassium

Potassium Potassium and Hypertension  Low potassium intakes increase blood pressure.  High potassium intakes prevent and correct hypertension. K may make blood vessels less sensitive to catecholamines – vasoconstriction

Water  Constitutes % of the total body mass. Muscle contains 65-75% water by weight. Water represents only about 50% of the weight of body fat.

Water Of the total body water  62% exists in the intracellular compartment  38% in the extracellular compartment plasma, lymph, and other fluids outside the cell.

Water  Provides structure and form to the body  Regulates temperature  Provides a medium for substances to interact chemically  Transports oxygen and nutrients

Water Intake  The average daily water intake comes from Liquid – about 1.2 L Food – about 1.0 L Metabolic water – about 0.3 L

Water Output  Daily water loss occurs from Urine – about L Insensible perspiration – about L Water vapor in expired air – about L Feces – about 0.10 L