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The Trace

Minerals

Chapter 13


The Trace Minerals – An

Overview

• Trace mineral contents of foods

• Vary with soil and water composition, and food

processing

• Deficiencies

• Can affect people of all ages

• May be difficult to recognize

• Toxicities

• FDA does not regulate trace minerals in

supplements


RDA (or AI) and UL Compared

for Selected Trace Minerals


Interactions

• Common and well coordinated to meet body

needs

• Sometimes lead to nutrient imbalances

• Excess of one causes a deficiency in another

• Or interfere with work of another mineral

• Contaminant minerals and toxic reactions

• Nonessential trace minerals

• Nickel, silicon, vanadium, cobalt, boron

• More needs to be learned


Iron

• Too little and too much can be harmful

• Roles in the body

• Switches back and forth between two forms

• Ferrous iron

• Ferric iron

• Cofactor in oxidation-reduction reactions

• Part of electron carriers

• Hemoglobin and myoglobin


Iron, continued

• Absorption

• Body conserves iron

• Balance maintained primarily through absorption

• Ferritin

• Iron storage in small intestine

• Transferrin

• Iron transport protein


Iron Absorption Process

Stepped Art Iron absorption process

If the body

does not

need iron Iron is not absorbed and is excreted in shed intestinal cells instead. Thus, iron absorption is reduced when the body does not need iron.

If the body

needs iron

Mucosal cells in the intestine store excess iron in mucosal ferritin (a storage protein).

Iron in food

Mucosal ferritin releases iron to mucosal transferrin (a transport protein), which hands off iron to another transferrin that travels through the blood to the rest of the body.


Heme and Nonheme Iron

• Types of iron

• Heme iron

• Found in animal foods

• High bioavailability

• Nonheme iron

• Found in plant and animal foods

• Absorption-enhancers for nonheme iron

• MFP

• Vitamin C

• Some acids and sugars


Heme and Nonheme Iron in

Foods

Stepped Art - Heme and nonheme iron in

foods

Heme accounts for about

10% of the average daily

iron intake, but it is well

absorbed (about 25%).

Nonheme iron accounts

for the remaining 90%,

but it is less well

absorbed (about 17%).

About 40% of the

iron in meat, fish,

and poultry is

bound into heme;

the other 60% is

nonheme iron.

All of the iron in

foods derived from

plants is nonheme

iron.

Key:

Heme

Nonheme


Factors that Inhibit Iron

Absorption

• Phytates

• Vegetable proteins

• Calcium

• Polyphenols

• Dietary factors combined

• Individual variation in absorption

• Health, stage in life cycle, and iron status


Iron Transport and Storage

• Transferrin delivers iron to bone marrow and

other tissues

• Storage

• Ferritin

• Hemosiderin

• Recycling

• Balance

• Regulating hormone hepcidin


Iron Recycled in the Body

Stepped Art

Some iron delivered to myoglobin of muscle cells

Some losses if bleeding occurs

Iron-containing hemoglobin in red blood cells carries oxygen.

Transferrin carries iron in blood.

Some losses via sweat, skin, and urine

Bone marrow incorporates iron into hemoglobin of red blood cells and stores excess iron in ferritin (and hemosiderin).

Liver (and spleen) dismantles

red blood cells, packages

iron into transferrin, and

stores excess iron in ferritin

(and hemosiderin).


Iron Deficiency

• Most common nutrient deficiency worldwide

• Populations affected in United States

• Link with obesity

• Vulnerable stages in life

• Women in reproductive years

• Pregnancy

• Infants and young children

• Adolescence


Assessment of Iron Deficiency

• Even small blood losses can cause deficiency

• Deficiency develops in stages

• Iron stores diminish – serum ferritin

• Decrease in transport iron transferrin

• Hemoglobin and hematocrit values decline

• Iron deficiency and anemia

• Anemia – severe depletion of iron stores

• Low hemoglobin concentrations

• Symptoms


Normal Blood Cells and Blood Cells

in Iron Deficiency Anemia Compared


Results of Iron Deficiency

• Behavioral symptoms

• Energy metabolism is impaired

• Neurotransmitter synthesis is altered

• Reduces work capacity and mental productivity

• Motivational problems

• Pica

• Craving and consumption of nonfood substances


Iron Overload

• Hereditary hemochromatosis

• Most common genetic disorder in United States

• Hemosiderosis

• Signs and symptoms

• Transferrin saturation and serum ferritin

• Characteristics of condition

• Treatment

• Research: targeting hepcidin activity


Iron and Chronic Diseases

• Heart disease

• Excess iron

• Free radicals

• Cancer

• Free radical damage

• Limited evidence

• Iron poisoning

• Symptoms of toxicity

• UL


Iron Sources

• Natural sources

• Meats, fish, poultry, legumes, eggs

• Enriched sources

• Flour and grain products

• Iron cookware

• RDAs

• Vegetarians

• Women

• Maximizing absorption


Iron in Selected Foods

Food

(Best Source per

kclalorie)

Serving Size (kcalories) Food Group Approximate Amount

of Iron (milligrams)

Bread, whole wheat 1 oz slice (70 kcal) Grains 1

Cornflakes, fortified 1 oz (110 kcal) Grains 0.9

Spaghetti pasta ½ c cooked (99 kcal) Grains 1

Tortilla, flour 1 10"-round (234 kcal) Grains 2.4

Broccoli ½ c cooked (22 kcal) Vegetables 0.6

Carrots ½ c shredded raw (24 kcal) Vegetables 0.3

Potato 1 medium baked w/skin (133 kcal) Vegetables 1.8

Tomato juice ½ c (31 kcal) Vegetables 1

Banana 1 medium raw (109 kcal) Fruits 0.5

Orange 1 medium raw (62 kcal) Fruits 0.1

Strawberries ½ c fresh (22 kcal) Fruits 0.3

Watermelon 1 slice (92 kcal) Fruits 0.4

Milk 1 c reduced-fat 2% (121 kcal) Milk and milk products 0.1

Yogurt, plain 1 c low-fat (155 kcal) Milk and milk products 0.1

Cheddar cheese 1½ oz(171 kcal) Milk and milk products 0.2

Cottage cheese ½ c low-fat 2% (101 kcal) Milk and milk products 0.1

Pinto beans ½ c cooked (117 kcal) Legumes, nuts, seeds 2.2

Peanut butter 2 tbs (188 kcal) Legumes, nuts, seeds 0.4

Sunflower seeds 1 oz dry (165 kcal) Legumes, nuts, seeds 1

Tofu (soybean curd) ½ c (76 kcal) Legumes, nuts, seeds 1.2

Ground beef, lean 3 oz broiled (244 kcal) Meats, poultry, seafood 2

Chicken breast 3 oz roasted (140 kcal) Meats, poultry, seafood 1

Tuna, canned in water 3 oz (99 kcal) Meats, poultry, seafood 1.3

Egg 1 hard cooked (78 kcal) Meats, poultry, seafood 0.8

Excellent, and sometimes unusual, sources:

Clams, canned 3 oz (126 kcal) Meats, poultry, seafood 18+

Beef liver 3 oz fried (184 kcal) Meats, poultry, seafood 5.4

Parsley 1 c raw (22 kcal) Vegetables 3.9


Some of Zinc’s Roles in the

Body

• Supports the work of hundreds of proteins

• Stabilizes cell membranes and DNA

• Immune function

• Growth and development

• Synthesis, storage, and release of insulin

• Blood clotting

• Thyroid hormone function

• Behavior and learning performance


Zinc Absorption

• Rate varies depending on amount consumed

• 10-40 percent

• May be used or retained in intestinal cells

• Recycling

• Small intestine

• Two doses of zinc

• Enteropancreatic circulation

• Zinc losses


Enteropancreatic Circulation

of Zinc

Stepped Art -

Enteropancreatic circulation of zinc.

If the body

needs zinc

If the body

does not

need zinc Mucosal cells in

the intestine store

excess zinc in

metallothionein.

Zinc is not absorbed and is excreted in shed intestinal cells instead. Thus, zinc absorption is reduced when the body does not need zinc.

Metallothionein releases

zinc to albumin and

transferrin for transport

to the rest of the body.

Zinc in food

The pancreas uses

zinc to make digestive

enzymes and secretes

them into the intestine.


Zinc Transport and Deficiency

• In the blood

• Albumin

• Transferrin

• Deficiency

• Widespread in developing world

• Middle Eastern diets inhibit zinc absorption

• Effects

• Growth retardation

• Impaired immune response

• Central nervous system damage


Zinc Toxicity and Sources

• Symptoms

• Interference with copper metabolism

• Sources

• Protein-rich foods

• Shellfish, meats, poultry, milk, and cheese

• Supplementation

• Developing countries

• May shorten duration of common cold


Zinc in Selected Foods

Food

(Best Source per

kclalorie)

Serving Size (kcalories) Food Group Approximate Amount

of Zinc (milligrams)

Bread, whole wheat 1 oz slice (70 kcal) Grains 0.6

Cornflakes, fortified 1 oz (110 kcal) Grains 0.1

Spaghetti pasta ½ c cooked (99 kcal) Grains 0.5

Tortilla, flour- 1 10"-round (234 kcal) Grains 0.6

Broccoli ½ c cooked (22 kcal) Vegetables 0.4

Carrots ½ c shredded raw (24 kcal) Vegetables 0.1

Potato 1 medium baked w/skin (133 kcal) Vegetables 0.5

Tomato juice ¾ c (31 kcal) Vegetables 0.4

Banana 1 medium raw (109 kcal) Fruits 0.2

Orange 1 medium raw (62 kcal) Fruits 0.1

Strawberries ½ c fresh (22 kcal) Fruits 0.1

Watermelon 1 slice (92 kcal) Fruits 0.3

Milk 1 c reduced-fat 2% (121 kcal) Milk and milk products 1

Yogurt, plain 1 c low-fat (155 kcal) Milk and milk products 2.1

Cheddar cheese 1½ oz(171 kcal) Milk and milk products 1.4

Cottage cheese ½ c low-fat 2% (101 kcal) Milk and milk products 0.7

Pinto beans ½ c cooked ( 1 17 koal) Legumes, nuts, seeds 1

Peanut butter 2 lbs (188 koal) Legumes, nuts, seeds 1

Sunflower seeds 1 oz dry (165 kcal) Legumes, nuts, seeds 1.5

Tofu (soybean curd) ½ c (76 kcal) Legumes, nuts, seeds 0.9

Ground beef, lean 3 oz broiled (244 kcal) Meats, poultry, seafood 4.2

Chicken breast 3 oz roasted (140 kcal) Meats, poultry, seafood 0.9

Tuna, canned in water 3 oz (99 kcal) Meats, poultry, seafood 0.8

Egg 1 hard cooked (78 kcal) Meats, poultry, seafood 0.6

Excellent, and sometimes unusual, sources:

Oysters 3 oz cooked (139 kcal) Meats, poultry, seafood 12+

Sirloin steak, lean 3 oz broiled (172 kcal) Meats, poultry, seafood 5.7

Crab 3 oz cooked (94 kcal) Meats, poultry, seafood 4.8


Iodine

• GI tract converts iodine in food to iodide

• Iodide: readily absorbed by the body


• Part of thyroid hormones that regulate:

• Body temperature

• Metabolic rate

• Reproduction and growth

• Blood cell production

• Nerve and muscle function


Iodine Deficiency

• Thyroid hormone production

declines

• Increased secretion of thyroid-

stimulating hormone (TSH)

• Cells of thyroid expand: goiter

• Goitrogen

• Preventable mental retardation

and brain damage

• Cretinism


Iodine Toxicity and Sources

• Toxicity

• Interferes with thyroid

function

• Enlarges thyroid gland

• Goiter in an infant

• UL

• Recommendations

• Sources

• Seafood

• Iodized salt


Selenium

• Substitute for sulfur in some amino acids

• Methionine, cysteine, and cystine

• Roles in body

• Antioxidant

• Part of proteins

• Glutathione peroxidase

• Enzymes activate or inactivate thyroid hormone


Selenium Deficiency

• Keshan disease

• Type of heart disease in regions of China where

soil lacks selenium

• Cancer

• May be protective factor

• Supplements have not proved effective

• Toxicity

• UL

• Effects


Selenium Sources

• Found in soil

• Meats, milk, and eggs

• Brazil nuts

• Recommendations

• RDA

• Amount needed to maximize glutathione

peroxidase activity


Copper

• Transport and balance depend on a system of

proteins

• Roles in body

• Constituent of enzymes

• Reactions that consume oxygen or oxygen radicals

• Iron metabolism

• Defense against oxidative damage

• Other roles


Copper Deficiency and Toxicity

• Possible link to cardiovascular disease

• United States’ diets provide adequate intake

• Excessive intakes

• Foods versus supplements

• Genetic disorders that effect copper status

• Menkes disease

• Wilson’s disease


Copper Sources

• Legumes

• Whole grains

• Nuts

• Shellfish

• Seeds

• Water delivered through copper plumbing


Manganese

• Body locations

• Bones

• Metabolically active organs

• Roles in body

• Cofactor for enzymes that facilitate metabolism

• Bone formation

• Conversion of pyruvate to a TCA cycle compound


Manganese Deficiency

• Requirements are low

• Deficiencies are rare

• Factors that limit manganese absorption

• Toxicity

• Environmental contaminate

• UL

• Recommendations

• AI set based on average intakes

• Source: grain products


Fluoride

• Found in bones and teeth

• Fluorapatite

• Dental caries

• Sources

• Drinking water

• Most bottled waters lack

fluoride

• Tea and fish

• Toxicity: fluorosis


Chromium


• Participates in carbohydrate and lipid metabolism

• Helps maintain glucose homeostasis

• Diabetes-like condition may result if chromium

lacking

• Sources

• Unrefined foods

• Liver, brewer’s yeast, whole grains

• Supplements


Molybdenum

• Working part of several metalloenzymes

• Dietary deficiencies are unknown

• Sources

• Legumes, breads, grain products, leafy green

vegetables, milk, and liver

• Toxicity is rare

• UL

• Characteristics


Contaminant Minerals

• Impair body’s growth, work capacity, and

general health

• Heavy metals

• Lead

• Indestructible

• Displaces nutrient minerals from metabolic sites

• Children with iron deficiency especially vulnerable

• Mercury

• Cadmium


Closing Thoughts on the

Nutrients

• Look at nutrients as a whole

• Work cooperatively with one another

• Actions are most often interactions

• Most foods deliver multiple nutrients


Phytochemicals

and Functional

Foods

Highlight 13


Phytochemicals

• Found in plant-derived foods

• Have biological activity in the body

• Physiological effects

• May prevent development of chronic diseases

• Adverse effects if consumed in excess

• Functional foods


Phytochemicals and Cancer

• Protect against DNA

damage

• Soybeans

• Phytoestrogens

• Tomatoes

• Lycopene


Phytochemicals and

Heart Disease

• Flavonoids

• Food sources

• Heart-protection factors

• Carotenoids

• Plant sterols

• Lignans

• Defending against other diseases


Functional Foods

• All foods that have a potentially beneficial

effect on health

• Whole

• Fortified

• Modified

• Characteristics similar to drugs

• Long term consumption may be necessary for

beneficial effect

• Cost


The Colors of Foods Rich in

Phytochemicals Red White-Brown Orange-Yellow Blue-Purple Green

Anthocyanins

Lycopene Allicin

Allyl sulfides Beta-carotene

Limonene

Anthocyanins

Ellagic acid

Phenolics

Beta-carotene

Lutein

Indoles

Beets

Cherries

Cranberries

Pink grapefruit

Pomegranates

Radicchio

Radishes

Raspberries

Red apples

Red peppers

Red potatoes

Rhubarb

Strawberries

Tomatoes

Watermelon

Bananas

Brown pears

Cauliflower

Chives

Dates

Garlic

Ginger

Leeks

Mushrooms

Onions

Parsnips

Shallots

Turnips

Apricots

Cantaloupe

Carrots

Lemons

Mangoes

Nectarines

Oranges

Papayas

Peaches

Persimmons

Pineapple

Pumpkin

Rutabagas

Squash

Sweet potatoes

Tangerines

Yellow peppers

Black currants

Blackberries

Blueberries

Dried plums

Eggplant

Elderberries

Plums

Purple figs

Purple peppers

Raisins

Purple cabbage

Purple grapes

Artichokes

Arugula

Asparagus

Avocados

Broccoli

Brussels sprouts

Cabbage

Celery

Cucumbers

Endive

Green apples

Green beans

Green grapes

Green onions

Green pears

Green peppers

Honeydew melon

Kiwifruit

Leafy greens

Limes

Okra

Peas

Snow peas

Spinach

Sugar snap peas

Zucchini


Unanswered Questions

• Research on safety and effectiveness still in

progress

• While products are available for purchase

• Questions to ask

• Does it work?

• How much does it contain?

• Is it safe?

• Is it healthy?

• Future foods

the trace minerals - accountax education physical education classroom health education i...tuna,...

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