chapter 7 minerals. the art of nutritional cooking, 3 rd edition baskette/painter © 2009 pearson...

Chapter 7Minerals

The Art of Nutritional Cooking, 3rd editionBaskette/Painter

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.2

Key Concepts Macrominerals are required in gram

quantities

Microminerals are required in milligram quantities

Minerals maintain health

Mineral deficiencies are common in certain regions of the world

Excess mineral intake is toxic

Foods vary in mineral content




Minerals Minerals are inorganic elements that

play an important role in maintaining good health,

Minerals help regulate body processes and provide structure for body tissues

We obtain minerals from food sources

They are absorbed in the stomach and through the intestines




Macrominerals

Also called major minerals, are essential minerals needed in the greatest amount (more than 100 milligrams a day)

Calcium, phosphorus, magnesium, sulfur, and the electrolytes potassium, sodium, and chloride




Microminerals

Needed in trace amounts (under 100 milligrams a day) and are essential as well

Chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc




Calcium Making, repairing, and maintaining bones

and teeth called mineralization, involves combining calcium

and phosphorus to create calcium phosphate deposited in bone protein matrix

the skeleton contains 99% of body calcium Binds with protein for other vital functions,

blood clotting muscle contraction, helps release neurotransmitters in the brain activate digestive enzymes

Excess blood calcium leads to respiratory or cardiac failure

Too little results in tetany




Nutrient Requirementfor Calcium

Adequate Intake (AI) for calcium is 1,300 milligrams for ages 9 to 18

1,000 milligrams for adults 19 to 50 years

adults 51 and over require 1,200 milligrams daily to prevent osteoporosis

a condition where bones become brittle and fragile

Absorption decreases in people over age 60




Food Sources

Milk and milk products, such as cheese and yogurt

in areas of the world where milk is not a prominent food, soy products (such as tofu and miso), edible seaweeds, oysters, and small fish with soft, edible bones (e.g., sardines) provide calcium

Soybeans and other legumes

Dark green leafy vegetables




Bioavailability

A nutrient’s chemical form, plus the presence and amounts of other nutrients in a food source, affect the absorption rate of a particular nutrient during digestion




Bioavailability of Calcium

Oxalic acid in spinach binds 95% of calcium so that it cannot be absorbed

beet greens and chocolate contain oxalic acid

calcium in these foods is poorly absorbed

Foods high in dietary fiber, phytic acid (found in wheat bran), and phosphates (found in brown rice) decrease calcium absorption




Calcium Deficiency

Osteoporosis has become a major problem in recent times

women are more susceptible than men Caucasian women more so than African-

American women women with small bones and fair

complexion are at a greater risk




Phosphorous All foods contain phosphorus, which is necessary for

energy production All cells contain phosphorus Most of the body’s phosphorus occurs in bones and

teeth bound with magnesium and calcium to provide strength and rigidity

Needed to convert sugar into energy for the body B vitamins that act as enzymes in carbohydrate

metabolism are phosphorylated, indicating they require phosphorous

RNA and DNA, carriers of genetic code, are phosphorylated as well

Some lipids (fats), such as lecithin, combine with phosphorus and then become part of all cells

Other fats are connected to phosphorus for transportation through blood

Also involved in body pH regulation




Nutrient Requirementfor Phosphorous

RDA for phosphorus is the same for males and females

1250 mg/d for children 9 – 18 years and 700 mg/d for adults 19 and older

the upper limit (UL) is set at 4,000 mg/d for males and females 9 – 70 years of age




Food Sources

If protein intake is adequate, so is phosphorus intake because phosphorus is a component of DNA and RNA and ATP so it is found in abundance in all protein foods




Deficiency

Because phosphorus is so abundant, deficiency rarely occurs




Magnesium Necessary to efficiently use amino acids in

protein formation Acts with many enzyme systems, particularly

in carbohydrate metabolism About 60% of the body’s magnesium is

contained in the bones Soft tissues contain more magnesium than

calcium Extra-cellular magnesium—indicating

magnesium outside the cell—is important in neuromuscular transmission




Nutrient Requirement for Magnesium

200 milligrams of magnesium daily

Since the mineral is only 30 to 40% absorbed, RDAs are 400 mg/d for men 19-30 years of age and 310 mg/d for women 19-30 years




Deficiency Deficiency produces vasodilation and

hyperirritability, which have led to convulsions and death in experimental animals

In humans, magnesium deficiency is rarely related to poor dietary intake

diuretic use, alcoholism, and medical conditions that lead to urinary losses are more likely causes of a magnesium deficit

Severe magnesium deficiency stemming from these conditions also causes calcium deficiency

Muscle twitching, tremors, numbness, and tingling are early symptoms




Toxicity

Individuals with kidney failure may experience magnesium overload




Food Sources

Nuts, especially cashews and almonds Whole grains Vegetables containing chlorophyll Protein foods, such as soy beans and

other legumes Dairy products are poor sources of

magnesium, as are most fruits Hard water contains significant

amounts of magnesium




Sodium One of the most important minerals in the

body

Along with potassium and chloride, it is known as an electrolyte

an element with a + or – charge that helps regulate water

Helps regulate acid/base balance, osmotic pressure, neuromuscular transmission of nerve impulses

Facilitates intestinal nutrient absorption




Nutrient Requirement for Sodium

Average daily sodium intake in the United States ranges from 6,000 to 10,000 milligrams

There is no RDA for sodium

AI for men and women ages 9 - 50 is 1,500 mg/d, and the UL is 2,300 mg/d

When heat or exercise leads to a 5- to 10-pound loss of body water, then the body may require additional sodium




Sodium Deficiency Deficiency can cause cardiac arrest,

convulsions, collapse, and heat exhaustion in humans with normal kidney and heart

functions, 90% of sodium is excreted through the kidneys

vomiting and diarrhea, especially in children, the frail, and the elderly, can cause large sodium losses, which might require medical attention

Dehydration and disturbance of the body’s acid/base balance can lead to death




Toxicity

Toxic only if large amounts of sodium and insufficient fluids are taken

can occur when a person has medical problems that create fluid retention inhibiting proper sodium excretion

Hypertension (high blood pressure) is the most common health problem linked with sodium




Hypertension

No symptoms at first; years later, a person can become short of breath, develop heart irregularities, suffer a stroke, or have a heart attack with little warning

epidemiological evidence suggests that in cultures with low salt intake, hypertension is rare

hypertension is common in cultures with high salt intake




Food Sources All natural foods contain sodium Extra dietary sodium comes from food

additives Fruits and oils have the least amount Cheese has a very high sodium content

processed cheese has even more sodium than natural cheese

Some over-the-counter and prescription drugs contain sodium

The greatest addition of dietary sodium comes from table salt added to season foods




Sodium-containing Preservatives

Sodium acetate Sodium aluminum sulfate Sodium benzoate Sodium bicarbonate Sodium citrate MSG




Potassium Potassium and sodium have interrelated

roles and some similar functions except that potassium operates inside the cell and

sodium functions outside it

Electrolytes regulate normal water balance, conduction and transmission of nerve impulses, muscle contractions, heart action, and some enzyme system functions

Through excretion and conservation, healthy kidneys help maintain steady levels of potassium and sodium




Food Sources All natural foods, except oil, contain

potassium Fruits and vegetables provide the most

potassium, followed closely by milk and meats

Whole grains contain more potassium than refined grains

Some medications and some salt substitutes also contain potassium

Processed foods contain potassium in the form of additives that help stabilize and preserve




Chloride Although the element chlorine is a

poisonous gas, chloride is its ionic form and a required nutrient

Main function is to maintain acid/base balance of the body and osmotic pressure

One of the body’s three mineral electrolytes

Binds with both sodium and potassium Becomes part of hydrochloric acid in

the stomach




Nutrient Requirement

There is no RDA for chloride

AI is set at 2,300 mg/d for young adults

UL is set at 3,500 mg/d




Deficiency or Toxicity

Although sodium is recognized as the mineral most closely related to high blood pressure, one study of hospitalized patients showed that sodium citrate salt did not raise blood pressure in the same way as sodium chloride (table salt)

Deficiency is unlikely unless dehydration results from excessive sweating, diarrhea, or vomiting




Food Sources

Table salt is a large dietary source of chloride

one-fourth teaspoon of salt contains 750 milligrams of chloride

Many processed foods, such as frozen meals, canned foods, snacks, cereals, dairy and lunch meats, contain chloride from salt




Sulfur

Important as a constituent of many body tissues and enzyme systems




Nutrient Requirement for Sulfur

There is no dietary reference intake (DRI) set for sulfur




Food Sources

Most sulfur in the diet comes from organic sources

Found in all flesh foods, milk, eggs, and vegetables of the cabbage family (cabbage, cauliflower, broccoli, and Brussels sprouts), legumes and nuts




Trace Minerals

Necessary for human life, but in small amounts

Iron




Iron Main function is manufacturing hemoglobin

in red blood cells hemoglobin transports oxygen to every cell and

carries carbon dioxide from cells to the lungs

An essential component of myoglobin, a receptor and storage point for some of the

oxygen in muscles

Stored in the liver, spleen, and bone marrow

Part of many enzymes




Nutrient Requirement for Iron

RDA for iron is based on the fact that iron is lost in feces, urine, and sweat at the rate of 1 milligram per day

only one-tenth of iron is absorbed

Allowances are set much higher than the loss: 8 milligrams per day for men

Substantially higher at 18 mg/d for women in the reproductive years

following the reproductive years, the requirement for women drops to only 8 milligrams of iron daily




Deficiency Deficiency is common in women and is the most

common deficiency world wide the usual symptoms are pallor, weakness, easy

fatigability, labored breathing on exertion, headache, palpitations, and persistent lethargy

Iron is of great importance during pregnancy

Many women are iron deficient even before pregnancy

infants need iron from their mothers before birth to accumulate a five-month supply

Nature prepares for the fact that an infant’s early diet is breast milk, which is low in iron but absorbed five times more efficiently than iron from cow’s milk

deficiency affects a child’s ability to learn and defend against infection




Food Sources There are two types of dietary iron:

heme iron non-heme iron

Heme iron is obtained from animal sources and is about 15 to 30% assimilated

Iron obtained from non-animal sources is non-heme iron, which is absorbed at the rate of 3 to 8% (some sources state ranges from 2 to 20%)




Iron Absorption Vitamin C aids absorption, other substances

block it Tannin in tea inhibits iron absorption by

binding non-heme iron Heme iron remains unaffected by tea Polyphenols in coffee inhibit iron absorption Oxalic acid in spinach, rhubarb, and

chocolate inhibit absorption Phytates in whole grains and soybeans also

inhibit absorption Phosvitin in egg yolks bind iron




Zinc Needed for healthy hair and nails Twenty percent of the total body zinc is

found in the skin Most zinc in the body is bound to enzymes

and is associated with carbon dioxide metabolism

At least 40 different enzyme systems require zinc

Appears to play a major role in the synthesis of nucleic acids, including DNA and RNA, and in protein synthesis

Wound healing also requires zinc




Nutrient Requirement for Zinc

RDA for zinc is 11 milligrams per day for adult males and pregnant women, and 8 milligrams for non-pregnant adult women

Absorption averages about 40% pregnancy and lactation require extra zinc

Children 1 to 8 years old need from 3 to 5 milligrams of zinc daily

Zinc intake should be proportional to protein intake




Deficiency and Toxicity Strict vegetarians are at risk for zinc

deficiency; but deficiency is rare Deficiencies are more likely the result of

genetic defects, disease, or burns Deficiency results in a rash on the face and

limbs, poor growth, loss of taste and smell, loss of hair, infertility, loss of sexual function in males, poor wound healing, and depression

Immunity may suffer with deficiency because the immune system requires zinc

Toxicity is uncommon because dietary excess is unlikely




Food Sources

Oysters are the best food source of zinc followed by herring

Other good food sources of zinc are milk, meat, eggs, seeds, whole grains, and brewer’s yeast

Human milk contains the most bioavailable form of zinc

Bioavailability from beef is about four times greater than that from high-fiber cereals




Iodine Needed to produce thyroxin, a

hormone made in the thyroid gland nearly all of the body’s iodine is located in

this gland

Thyroxin regulates body heat and influences protein synthesis, cell metabolism, and basal metabolic rate

Thyroxin also keeps connective tissues healthy, and promotes physical and mental development




Nutrient Requirement for Iodine

RDA for iodine is set at 150 micrograms per day for adults

infants and children need less average intake is usually well above the

requirement because of liberal use of iodized salt




Deficiency

Deficiency (less than 50 micrograms daily) causes thyroid gland enlargement so it can use all available iodine

this enlargement is called goiter and protrudes visibly from the neck

Iodine deficiency during the first three weeks of pregnancy can result in the birth of a child who is a dwarf and mentally deficient




Toxicity

Excessive iodine (25 to 70 times the RDA) leads to high levels of thyroxin and corresponding thyroid enlargement, impaired glucose tolerance, and heart failure

Excessive intake can also cause hypothyroidism resulting in slowed metabolic rate and listlessness because the thyroid stops producing thyroxin




Food Sources Saltwater fish are excellent sources

land near the ocean and land once covered by the sea are rich in iodine

foods grown in these iodine-rich soils and products such as milk from animals feeding on this land are natural sources of iodine

The US diet may contain extra iodine as a result of using iodine sanitizers on utensils and processing equipment in food manufacturing

Certain food colors and dough conditioners also contain iodine

Iodized salt, 1924, was an important health intervention that eliminated goiter in the United States




Selenium

Protecting cell membranes from oxidative damage

Part of glutathione peroxidase, an enzyme that neutralizes hydrogen peroxide

Binds to a blood protein carrier and defends against oxidants

Plays a role in electron transfer function Protects against cadmium and mercury

toxicity




Nutrient Requirement for Selenium

RDA for selenium is set at 55 micrograms for adults




Deficiency and Toxicity Excess is toxic

cattle grazing in pastures with high concentrations of selenium develop symptoms of hair loss; long-bone joint erosion that causes lameness; blindness; and liver disease

animals sometimes die from selenium toxicity

Humans develop problems with intakes only 10 times the RDA

UL is set at 400 micrograms per day for adults

Liver failure caused by selenium toxicity can lead to death




Deficiency

Deficiency is a problem in regions of China where soil is deficient in selenium

Children ingesting less than 38 micrograms of selenium daily develop Keshan disease




END

chapter 7 minerals. the art of nutritional cooking, 3 rd edition baskette/painter © 2009 pearson...

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