CHAPTER 8: MINERALS

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INTRODUCTION In Nutrition we focus on mineral

elements – single atoms that are simple – as compared with vitamins which are large, complex, organic compounds.

Minerals perform a wide variety of metabolic tasks essential to human life.

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OBJECTIVES

Identify the nature of body mineralDescribe the issue of mineral

supplementationIdentify the major mineralsIdentify the trace elements

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KEY CONCEPTS The human body requires a variety of

minerals in different amounts to perform numerous metabolic tasks

The body cannot make any minerals; therefore they must be consumed in the diet

A mixed diet of varied foods and adequate energy value is the best source of the minerals necessary for health

Of the total amount of minerals a person consumes, only a relatively limited amount is available to the body 4

DEFINITION

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Minerals are single inert (inorganic) elements.

Mineral micro nutrients perform a variety of metabolic tasks essential to human life.

THE NATURE OF BODY MINERALSLiving matter is made up of four fundamental

elements:Hydrogen, carbon, nitrogen, oxygen

There are 25 minerals known to be essential to human life They perform a variety of metabolic

functionsThe amount of each mineral is specific for its

task E.g. Calcium: 3lbs of C+ in a 150 lb. personE.g. Iron: 0.11 oz of Fe in a 150 lb. person

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CLASSES OF BODY MINERALS

Major minerals = the amount of the mineral. Those requiring an intake of more than

100 mg/day7 major minerals:

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

Trace elements = Those requiring less than 100 mg/dayE.g. iron, copper, zinc the remaining 18

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FUNCTIONS OF MINERALS

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Minerals help control many of the body’s metabolic processes. They help: build, activate, regulate, transmit, and controlE.g. Sodium and

Potassium – control water balance

E.g. Iron helps build hemoglobin (the vital oxygen carrier in the body)

E.g. Calcium and phosphorus are required for building bone

FUNCTIONS OF MINERALSMineral Metabolism

The correct amount of minerals for the body’s needs is usually controlled at the point of intestinal absorption or the points of tissue uptake

Digestion – minerals are absorbed and used in the body in their activated ionic form. They do not require a great deal of mechanical or chemical digestion before absorption.

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FUNCTION OF MINERALSMineral Metabolism cont.

Absorption – affected by: 1. Food form – minerals in animal foods more

readily absorbed 2. Body need – if deficient, more is absorbed 3. Tissue health - if the absorptive surface is

affected by disease, its absorptive capacity is greatly diminished

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FUNCTIONS OF MINERALSTransport – Minerals enter the portal circulation and

travel throughout the body bound to plasma protein or mineral-specific protein

Tissue uptake – Uptake of some minerals are controlled by hormones and excess minerals are excreted into the urine

E.g. TSH – controls the uptake of iodine from the blood to make the thyroid hormone “thyroxine”

Occurrence in the body – Minerals are either: 1. free ions – in body fluids2. Covalently bound – i.e. combined with other

minerals or organic substances11

MAJOR MINERALS12

CALCIUMCalcium

One of the minerals most likely to be deficient in a typical diet.

It’s intestinal absorption depends on: 1. Food form and 2. The interaction of 3 hormones:

Vitamin D hormonePTHCalcitonin

Indirect control by the estrogens

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CALCIUM CONT.Functions- Once calcium is absorbed, it has 4 basic

functions:Bone and tooth formation – 99 % is found in

bones and teeth1 – 2 % of normal adult body weight is calcium Blood clotting – calcium is essential for the

formation of fibrin to compose a blood clotMuscle and nerve action – Ca+ ions

are required for muscle contraction and the release of neurotransmitters from neuron synapses

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CALCIUM (CONT.)

Metabolic reactions – Intestinal absorption of B12, activation of fat-splitting enzyme lipase, secretion of insulin, and cell membrane permeability all need calcium

Requirements: Adequate Intake by age group: 19-50 years (male/female) 1000mg/day over 51 years 1200 mg/day Increased needs during pregnancy and lactationUL = 2500mg/day 15

CALCIUM CONT. Deficiency states

Bone deformities d/t insufficient calcium available during growth years

Rickets – inadequate Vit D to absorb calciumOsteoporosis –

abnormal thinning of bone – esp. post menopausal women;

characterized by reduced bone mass, increase fragility, and increased risk for fx.

Contributing factors – poor calcium intake, poor intestinal absorption, lack of physical exercise, immobility after injury or disease.

See p. 132: Cultural Considerations: Bone Health in Gender and Ethnic Groups

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CALCIUM CONT.

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Toxicity symptoms:kidney stones;

interferes with intestinal absorption of other minerals

Food Sources: Dairy, dairy products; calcium-fortified foods/drinks; some greens (low oxalate: bok choy, broccoli, collards, kale, turnip greens)

See Table 8-1 p. 133

PHOSPHORUS

Serves as a partner with calcium in bone formation (calcium phosphate/hydroxyapatite)

Functions- Bone and tooth formation – calcification of bones

and teeth depend on the deposition of hydroxyapatite (Ca+, Ph)

Energy metabolism – Helps controls oxidation of carbohydrates, fats and proteins in producing and storing available energy

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PHOSPHORUS CONT.

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Functions cont.Involved in protein

construction, cell function, and genetic inheritance

Acid-base balance – an important buffer material that maintains pH homeostasis of body fluids Normal pH = 7.35-7.45)

PHOSPHORUS CONT.Requirements

RDA for men and women 19 yrs. and older = 700 mg/day.

No increase for pregnant or lactating womenUL = 4000mg/day 9yrs old -> 70 yrs old

Deficiency states:Rare, but has been seen with excessive aluminum

hydroxide intake (antacids which bind phosphorus and make it unavailable for absorption).

Deficiency results in: Bone loss, weakness, loss of appetite, fatigue, pain

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PHOSPHORUS CONT.

Toxicity symptoms – rare; however, if phosphorus intake is significantly higher than calcium intake for a long period of time, bone resorption may occur

Food sources – animal and plant cells; milk, meat, fish, eggsSee Table 8-2, p.135

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SODIUMOne of the most plentiful minerals in the bodyAbout 4.2 oz found in the adult body Functions:

Water balance: (main) Ionized sodium is the major influence on the volume of

the body’s water balance outside of the cells -> helps to prevent dehydration The variation in sodium concentration largely controls

the movement of water across biologic membranes. This movement of water from a greater concentration to a lesser concentration is called osmosis.

Also an integral part of digestive juices secreted into the GI tract

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SODIUM CONT.

Muscle Action: Sodium ions, in partnership with potassium, are necessary for the normal response of stimulated nerves, the transmission of nerve impulses to muscles, and the contraction of muscle fibers

Nutrient Absorption : Essential part of the cell membrane system; transports glucose and galactose across membranes in the small intestine

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SODIUM SOURCE

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SODIUM CONT.

Requirements The body is able to function on various amounts

through mechanisms designed to conserve or excrete this mineral as needed

No RDAIndividual sodium needs vary greatly depending on

growth stages, sweat loss, medical conditionAI: Approx. 1.5g/day for healthy persons should

meet the need50-70 years old AI: 1.3g71years + AI: 1.2gUL = 2.3g/day

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SODIUM (CONT.)

Deficiency states- Rare. Exceptions occur during heavy body sweating acid-base problems and muscle crampingStrenuous exercise for 2+ hrs, esp. in heat or

endurance events should drink fluid with electrolyte replacement

Toxicity symptoms- Hypertension and edemaPeople with healthy kidneys usually excrete excess

Na+Acute excessive intake of Na+ (eg. Table salt)

accumulation of Na+ in extracellular spaces pulls water out of cells into the extracellular space (by osmosis) edema 26

SODIUM (CONT.)

Food sources – Table salt as used in cooking, seasoning,

and processing foods;Natural occurrence: food of animal origin

– i.e. milk, meat, eggs, vegetables such as carrots, beets, leafy greens, and celery

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POTASSIUMThe adult body contains approx. 270mg

(9 oz) of potassium – nearly 2x the amount of sodiumFunction:

Water balance – the major electrolyte controlling the water inside the cell (intracellular). It balances with the sodium concentration in the extracellular fluid

Metabolic reactions – plays a role in the conversion of blood glucose to stored glycogen, for synthesizing of muscle protein, and production of energy

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POTASSIUM CONT.

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Function cont.Muscle action –

contribute to nerve impulse transmission to stimulate muscle action.

Note: Along with magnesium and sodium, potassium acts as a muscle relaxant in balance with calcium, which causes muscle contraction. The heart muscle is very sensitive to potassium levels.

POTASSIUM CONT.

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Function cont.Insulin release –

Needed for the release of insulin from pancreatic cells in response to a rise in blood-glucose levels

Blood pressure – Elevated BP may be more related to the sodium-potassium ratio than the amount of dietary sodium alone.

POTASSIUM CONT.Requirements

No RDAAI = 4.7g/day for all adultsTypical American diet provides a daily intake of 2-

3g/dayDeficiency states – may develop during situation

as prolonged vomiting or diarrhea; use of diuretic drugs, severe malnutrition, or surgery.Characteristic symptoms: heart muscle problems

including cardiac arrest; weakness of respiratory muscles with breathing difficulties; poor intestinal muscle tone with resulting bloating and overall muscle weakness

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POTASSIUM CONT.Toxicity symptoms – cardiac arrest

Kidneys normally excrete excess K+Excess PO. or IV. K+ increased blood

concentration of K+ heart muscle weakness cardiac arrest

Food sources – unprocessed foods provide the richest source of potassium; oranges, bananas, green leafy vegetables, broccoli, milk, fresh meatsTable 8-3, p. 138

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CHLORIDEThe chemical form of chlorine as it appears in the

human body Accounts for 3 % of mineral content in bodyFound in extra cellular fluid compartments where it

helps control the water and acid-base balances.Function

Digestion: Key element in hydrochloric acid secreted in the gastric juices

Respiration: helps RBC’s transport large amts. carbon dioxide to lungs for release

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CHLORIDERequirements

AI = for young adults : 2.3g/dayNeed declines gradually after 50 yrs oldNo UL

Deficiency states – does not occur under normal circumstances. Primary reason for excess chloride loss is vomiting acid-base balance disturbance (metabolic alkalosis)

Toxicity symptoms – severe dehydration can cause increased chloride level

Food sources – almost entirely provided by sodium chloride (table salt)

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MAGNESIUM

Found in all body cellsAdult body contains a little less than 1 oz.About 60% of magnesium is present in the bonesFunctions-

General metabolism – a necessary cofactor for more than 300 enzyme reactions in cells that produce energy, synthesize body compounds, or absorb and transport nutrients

Protein synthesis – Activates amino acids for protein synthesis; facilitates the synthesis and maintenance of cell genetic material, DNA [cell replication requires a precise amount of magnesium to function correctly]. 35

MAGNESIUM CONT.

Muscle action – conduct the nerve impulses that stimulates muscle contraction. Mg with Ca in balance acts as a relaxant during muscle activity, after a contraction.

Basal metabolic rate – Influences the secretion of the thyroid hormone thyroxine – helps to adapt to temperature and maintain a normal metabolic rate

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MAGNESIUM CONT.Requirements – RDA by age group and gender: ages 19-30 yrs

Men 400 – 420 mg/day Women 310 – 320 mg/dayUL= 350mg/day for persons 9 yrs old plus from supplemental

sourcesDeficiency states:

Very rare in persons consuming a natural dietSeen in clinical situations such as: starvation, persistent

vomiting or diarrhea, and surgical traumaSeen in diseases involving CV, and neuromuscular function,

diabetes mellitus, kidney disease, and alcoholismS/S.: muscle weakness and cramps, HTN, blood vessel

constriction in the heart and brain

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MAGNESIUM CONT.

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Toxicity symptoms –People with renal insufficiency are at increased risk for developing toxicity with dietary supplements. S/S. - Nausea, Vomiting, Diarrhea

Food sources – Whole grains, nuts, legumes, green vegetables, seafood, cocoa; hard water Unprocessed foods have the highest content of magnesium.

SULFURAn essential part of protein structurePresent in all body cellsFunctions:

Hair, skin, and nails – in the structure of hair, skin, and nails through presence in two amino acids that are concentrated in the tissue protein keratin

General metabolic functions – combined with hydrogen, it is important as a high-energy bond in building many tissue compounds. Helps transfer energy as needed in various tissues

Vitamin structure – part of vitamins that in turn act as coenzymes in cell metabolism ( thiamine, and biotin)

Collagen structure – Helps build connective tissue

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SULFUR CONT.Requirements – No RDA. No ULDeficiency states – None reportedToxicity symptoms –unlikelyFood sources – Meats, eggs, cheese, nuts

and legumesNote: a diet that contains adequate

protein contains adequate sulfurSee p. 141 Table 8-4

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TRACE MINERALS41

IRON Essential for life; toxic in excessHuman body contains about 45 mg/kg body wt.Function

Hemoglobin synthesis 70 % of iron occurs in the hemoglobin within RBCs

An essential component of “heme” which is the non protein part of the hemoglobin structure. Hemoglobin in RBCs carries oxygen to cells

A necessary part of “myoglobin” – a similar compound (to hemoglobin) in muscle tissue

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IRON CONT.General metabolism – Iron is needed for

glucose metabolism in cells, antibody production, drug detoxification in the liver, collagen and purine synthesis, and conversion of carotene to Vitamin A

RequirementsNeeds vary throughout lifeRDA: ages 9 and up = 8-11mg/day for males;

8-18mg/day for femalesWomen require more iron to cover the losses

during menstruation and pregnancyUL = 45g/day for adult

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IRON CONT.Deficiency states – iron deficiency anemia is the

most prevalent nutritional problem in the world today!Anemia: characterized by a decrease in the

number or RBCs or a drop in the amount of cell hemoglobin or both

Toxicity symptoms – from a single large dose (20-60mg/kg) can be fatalnausea, vomiting, diarrhea; liver, kidney, CNS damage

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IRON TOXICITY SYMPTOMS CON’TIf untreated, chronically elevated iron may

impair absorption of zinc, cause GI upset, and pose increased risk for heart disease and cancer

Hemochromatosis – genetic disorder iron overload widespread organ damage over timeTreatment – reduce iron intake; withdraw

blood regularlyFood sources – meat, eggs, vegetables, cereal.The body absorbs iron more easily in

conjunction with Vit CTable 8-6, p. 144 45

IODINEAverage adult body contains 20-50 mg. of

iodineFunctions:

Basic function: Participate in the thyroid gland’s synthesis of the hormone, thyroxine, which helps to control BMR

TSH (thyroid stimulating hormone) from the pituitary gland controls the thyroid gland’s uptake of iodine, in direct response to the level of thyroxine circulating in the blood

Requirements RDA for persons 14yrs + is: 150 ug/day

UL= 1100 mcg/day

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IODINE CONT.Deficiency states

Goiter – An enlargement of the thyroid gland d/t lack of iodine in the diet

Cretinism – characterized by physical deformity, dwarfism and mental retardation due to lack of iodine during pregnancy

Hypothyroidism-Myxedema – d/t a poorly functioning thyroid gland; cannot make enough thyroxine, and the BMR greatly reduced thin course hair, dry skin, poor cold tolerance weight gain and low husky voice

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IODINE CONT.Deficiency States cont.

Hyperthyroidism – accelerated thyroid gland produces excessive thyroxine BMR increased also known as Graves disease, protruding eyeballs (exopthalmos), weight loss, hand tremors, general nervousness, increased appetite, intolerance of heat

Toxicity symptoms – acne-like skin lesions; “iodine goiter” which may be misdiagnosed

Food sources – salt and sea food; presence of salt in processed foods

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IODINE DEFICIENCY GOITER

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ZINCEssential trace element, needed during

growth periods such as pregnancy, lactation, infancy, childhood and adolescence.

Present in minute quantities in:All body organs, tissues, fluids, and

secretions

FunctionsEnzyme constituent – Broad metabolic

activity that is an essential part of cell enzyme systems.Role in protein metabolism is associated with wound healing and health skin; has great influence on any rapidly growing tissues

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ZINC CONT.Functions cont.

Immune system – a considerable amount of zinc bound to protein is present in the leukocytes (WBCs), which are a major component of the body’s immune system

Other functions –stabilizes insulin in pancreas, involved in the protection of RBCs from oxidative damage

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ZINCRequirements – AI:

adult males 14yrs and older: 11mg/dayAdult females 18+ years old: 8mg/dayUL = 40mg/day

Deficiency states Impaired physical and sexual maturation where

dietary intake is low (e.g. dwarfism)Impaired taste and smellPoor wound healing, hair loss, diarrhea, and skin

irritation

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ZINC

Toxicity symptoms Uncommon Nausea, vomiting, decreased immune function,

impaired copper absorption with prolonged supplementation in excess of recommendations

Food sources – Meat, seafood (especially oysters), whole grains and legumes

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SELENIUMSelenium is present in all body tissue except fatHighest concentration is in liver, kidneys, heart and

spleen

Functions Works with specific proteins as an essential part of

an antioxidant enzymeA part of the protein center of teethThe enzyme that converts thyroid hormone to T3;

the antioxidant defense system of the body along with Vit. C

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SELENIUM CONT.

RequirementsRDA 55ug for men/women 14yrs and older

Deficiency statesImpaired immune functionKeshan disease- degenerative heart muscle ->

Heart muscle failure from cardiomyopathySee Table 8-8, Food Sources, p. 152

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SELENIUMToxicity symptoms – Brittleness of hair and nails,

GI disturbance, skin rash, garlic odor, nervous system abnormalities

Food sources – Seafood, kidney, liver, meatsNote: The amount of selenium in food depends

on the quantity of selenium in the soil used to graze animals and grow plants

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FLUORIDE

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Fluoride forms a strong bond with calcium and accumulates in calcified body tissues such as bone and teeth Main function in human nutrition: Prevent cavities. It

strengthens tooth structure to withstand the erosive effects of bacterial acids

Stimulates new bone formationRequirements: AI = men 4 mg and women 3 mg

UL = 10mg/daySources – fluoridated water and toothpaste, fish, fish

products, tea

COPPER

A component of cell enzymesAssociated with iron in energy production and

hemoglobin synthesisRequirements: RDA 900 ug/day for adults

UL = 10 mg./dayDeficiency – anemia and bone abnormality

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COPPER CONT.

Toxicity:Wilson’s disease : a genetic disorder which

causes the body to increase the storage of copper in the body liver and nerve damage

Food Sources: organ meats – esp. liver; sea food, whole grains, legumes, nuts, and seeds

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MANGANESE

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Essential part of cell enzymes that catalyze many important metabolic reactions

Deficiency is rare, but has been reported in cases of

diabetes and pancreatic insufficiency, and malnutrition state of Kwashiorkor.

AI = 2.3 mg/day for men and 1.8mg/day for women over 19yrs oldUL from dietary sources = 11mg./day

MANGANESE CONT.Toxicity: occurs as an industrial disease,

inhalation toxicity, in miners and other workers with prolonged exposure to manganese dust. The excess manganese accumulates in the liver and CNS, producing severe neuromuscular symptoms similar to those of Parkinson’s disease

Food sources: plant sources: whole grains, cereal products, and teas are the richest sources

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CHROMIUM

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Function:as an essential component of the organic

complex glucose tolerance factor (GTF), which stimulates the action of insulin. Insulin resistance has responded positively to chromium supplements, restoring normal blood sugars

Chromium supplements are also effective in the treatment of elevated serum cholesterol, lowering LDL cholesterol and increasing HDL cholesterol

AI: men 35 ug/day; women 25 ug/day

Found in Whole grains, cereal products, brewer’s yeast

MOLYBDENUMFunctions as a catalyst component of

several cell enzyme systems and is essential for a number of metabolic reactions

Deficiency States: inadequate dietary intake is unlikely

RDA: 45 ug/day for adultsUL = 2000 mcg/day for adults 19yrs old +

Found in organ meats, milk, whole grains, leafy vegetables and legumes

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MINERAL SUPPLEMENTATIONLife cycle needs – may need supplementation

during periods of rapid growth:Pregnancy/lactation AdolescenceAdulthood – clinical deficiencies, life

situations, endurance events

Clinical needs: supplementation may be needed for:Iron-deficiency anemia – the following high

risk groups may need to supplement their diets – adolescent girls and women during childbearing years on a poor diet; low income adolescent boys; athletes, vegetarians, and the elderly

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MINERAL SUPPLEMENTATION CONT.Weight-loss programs – esp. for

women, consider BMD loss and iron status

Zinc Deficiency – at risk individuals include: those on plant-based vegetarian diets, children and the elderly, alcoholics, those on long-term low calorie diets

Potassium-losing drugs – long term use, need K+ replacement

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