WATER AND MINERALS

Describe how the body regulates water intake and excretion to maintain water balance... GENERAL MINERAL FUNCTIONS Acid Base Balance Cofactors in enzyme reactions Components of essential

FCNS 201 SECTION 1 HUMAN NUTRITION

CHAPTER 9 WATER AND MINERALS

Joan Quinn, MEd., RD, LD

LEARNING OBJECTIVES

1 Discuss the major roles of water in the body and the amount of water needed by adults

2 Describe how the body regulates water intake and excretion to maintain water

balance.

LEARNING OBJECTIVES,

cont.

3 Compare the arguments for and

against drinking bottled water.

4 Explain the role of minerals in

maintaining the body’s fluid and

electrolyte balance.

LEARNING OBJECTIVES,

cont.

5 List the major roles and important

deficiency and toxicity symptoms for each major and trace mineral.

6 List good food sources for the major and trace minerals

MINERAL TRIVIA

4% of adult weight is mineral

There are 21 essential known minerals, including copper, zinc, and of course iron Body tolerances vary widely, with some minerals having very narrow lines

between deficiency and toxicity

GENERAL MINERAL

FUNCTIONS

Acid Base Balance

Cofactors in enzyme reactions

Components of essential body

compounds-blood, bone

Water balance

Transmission of nerve impulses

Regulation of muscle contractions Growth

Not all ingested minerals can be fully absorbed

Animal products are better absorbed

♦ Fiber Mineral interactions

♦ Mineral-Mineral interactions

♦ Vitamin-mineral interactions

♦ Mineral toxicities

Toxicity of Minerals

Trace minerals

Usually through supplementation Risk of contamination

THE MAJOR MINERALS

> 100 MG/DAY

Calcium, phosphorus, magnesium, sodium, potassium, chloride, sulfur

About 25% of food calcium absorbed

♦ Up to 60% when need is high

ABSORPTION OF CALCIUM

Factors decreasing absorption

♦ Phytic Acid in grains

♦ Excess Dietary Protein

Food Sources of Calcium

Dairy products

Kale, collard, mustard greens

Calcium fortified foods

Tofu (if made with calcium carbonate)

Canned fish

Daily Value is 1000 mg/day

Adequate Intake is 1000 -1200 mg/day for

adults

Current intake is below the AI

Abnormalities of CA

Metabolism

Osteoporosis-failure to maintain bone mass not related to Vitamin D deficiency, drug interactions or cancer

Tetany-inability to relax muscles after

contraction

Decrease bone mass

Related to aging, poor diet, and hormone Leads to 1.5 million bone fractures per

Bone Strength

Depends on bone mass and bone mineral density

Related to age, gender, and genetics

Peak Bone Mass achieved by age 20-30

Dual Energy X-ray Absorption (DEXA)

bone scan

♦ Enhance absorption due to acidity content

♦ Recommended for elderly

Risks With Supplements

No FDA regulation

Oyster shell

Bone meal and lead

Look for United States Pharmacopoeia seal

of approval

Too Much Calcium

Kidney stones/failure

Calcium in the urine

High calcium in the blood

Calcification of tissue

Upper level set at 2500 mg/day

Low intake linked to bone loss

Body absorption is high (~70%)

Widely available in foods

Absorption enhanced by vitamin D

Excess excreted by the kidney

Component of enzymes, ATP, DNA cell membrane, and bone

PHOSPHORUS FOOD

SOURCES

Various foods: milk, meat, cheese, bread Some from food additives (soft drinks)

Most difficult to limit intake of

Current intakes exceed RDA

Deficiency highly unlikely

Toxicity

Inefficient kidney function

Phosphate ions bind calcium

♦ Calcium to Phosphorus ratio

May compound bone loss if calcium intake is low

Upper level set at 3-4 grams per day

Functions of Magnesium

Nerve and Heart function

Aids enzyme reactions

Primarily in plants (chlorophyll)

Absorption based on body’s needs and calcium intake

Absorption enhanced by vitamin D

Found in bones

FOOD SOURCES OF

MAGNESIUM

LITTLE PRECISE INFORMATION

♦ Cocoa, Dairy, Meta

♦ Nuts, Seeds

♦ Whole grains, vegetables

♦ Hard tap water

♦ RDA is 420 mg for men, 320 mg for women

♦ Daily Value is 400 mg/day

♦ Average intake is lower than Daily Value

Deficiency of Magnesium

Irritability

Convulsion

Irregular heart beat

Weakness and disorientation

Body stores it readily

Deficiency develops slowly

Excessive diuretic and alcohol use, heavy perspiration, diarrhea and vomiting

Toxicity of Magnesium

Uncommon

Associated with kidney disorder

Overuse of magnesium containing mediations (antacids, laxatives)

Weakness, nausea, malaise

Elderly at risk

Upper Level is 350 mg/day (nonfood source)

FUNCTIONS OF SODIUM

Major extracellular ion

Maintains osmotic pressure

Acid-base balance

Nerve impulses and muscle contractions Essential for absorption of glucose and other nutrients

♦ Average American diet yields 4-7g/day or more

Daily Value is 2,400 mg per day

Intake > 2gm can increase urinary calcium loss

SODIUM FOOD SOURCES

Naturally occurring

♦ Milk, celery, eggs

Added in processing

♦ Ham, sauerkraut, sardines, pickles

Also consider that added in cooking, and the table, and to the water supply

SODIUM, cont.

Deficiency and excesses

♦ Generally not a concern since kidneys can readily adapt

♦ Most of the concern is in relation to clinical diagnosis

✔ Hypertension

✔ Kidney and liver disease

“Salt Sensitive”

10%-15% of adults are

High sodium intake leads to high blood pressure

Recommend 2-3 gm sodium per day

Recommended for all individual

Adapt to a low-sodium diet

FUNCTIONS OF

POTASSIUM

Major intercellular ion

Maintenance of osmotic pressure

Energy release

Acid base balance

Nerve transmission

Acts with mg for muscle relaxation

Associated with lowering blood pressure

Deficiency and Toxicity

Deficiency

♦ Rare

♦ Use of diuretics

♦ Alcoholics, anorexia nervosa, bulimia nervosa

✔ Loss of appetite, muscle cramps, confusion,

constipation, irregular heart beat-possible death

Potassium Requirement

Minimum requirement is 2000 mg/day Typical intake is > 2000 mg/day!

Negative ion for the extracellular fluid

Components of hydrochloric acid (HCl), immune response, nerve function

Excess is excreted by the

kidneys/perspiration

Minimum requirement is 700 mg/day

Much is obtained from salt consumption May also cause high blood pressure

CHLORIDE (HCL)

Functions

♦ Helps maintain stomach acidity

♦ Acid base balance

Component of amino acid and vitamins Acid-base balance

♦ Part of a natural diet, primarily from protein

♦ Used to preserve foods