Download The Trace Minerals

The Trace
Minerals
Chapter 13
©2016CengageLearning.AllRightsReserved.
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
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RDA (or AI) and UL Compared
for Selected Trace Minerals
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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
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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
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Iron, continued
• Absorption
• Body conserves iron
• Balance maintained primarily through absorption
• Ferritin
• Iron storage in small intestine
• Transferrin
• Iron transport protein
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Iron Absorption Process
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Iron in food
Mucosal cells in the
intestine store excess
iron in mucosal ferritin
(a storage protein).
If the body
does not
Iron is not absorbed and is
need iron
excreted in shed intestinal
cells instead. Thus, iron
absorption is reduced when
the body does not need iron.
If the body
needs iron
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.
Stepped Art
Iron absorption process
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
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Heme and Nonheme Iron in
Foods
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About 40% of the
iron in meat, fish,
and poultry is
bound into heme;
the other 60% is
nonheme iron.
Key:
Heme
Nonheme
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%).
All of the iron in
foods derived from
plants is nonheme
iron.
Stepped Art
- Heme and nonheme iron in
foods
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
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Iron Transport and Storage
• Transferrin delivers iron to bone marrow and
other tissues
• Storage
• Ferritin
• Hemosiderin
• Recycling
• Balance
• Regulating hormone hepcidin
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Iron Recycled in the Body
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Some losses
via sweat, skin,
and urine
Transferrin carries
iron in blood.
Some iron
delivered to
myoglobin of
muscle cells
Liver (and spleen) dismantles
red blood cells, packages
iron into transferrin, and
stores excess iron in ferritin
(and hemosiderin).
Some losses
if bleeding
occurs
Bone marrow incorporates
iron into hemoglobin of red
blood cells and stores
excess iron in ferritin
(and hemosiderin).
Iron-containing
hemoglobin in
red blood cells
carries oxygen.
Stepped Art
Iron Deficiency
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•
•
•
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
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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
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Normal Blood Cells and Blood Cells
in Iron Deficiency Anemia Compared
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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
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Iron Overload
• Hereditary hemochromatosis
•
•
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•
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Most common genetic disorder in United States
Hemosiderosis
Signs and symptoms
Transferrin saturation and serum ferritin
Characteristics of condition
Treatment
Research: targeting hepcidin activity
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Iron and Chronic Diseases
• Heart disease
• Excess iron
• Free radicals
• Cancer
• Free radical damage
• Limited evidence
• Iron poisoning
• Symptoms of toxicity
• UL
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Iron Sources
• Natural sources
• Meats, fish, poultry, legumes, eggs
• Enriched sources
• Flour and grain products
• Iron cookware
• RDAs
• Vegetarians
• Women
• Maximizing absorption
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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
Carrots
½ c shredded raw (24 kcal)
Vegetables
0.6
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
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Some of Zinc’s Roles in the
Body
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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
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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
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Enteropancreatic Circulation
of Zinc
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Zinc in food
Mucosal cells in
the intestine store
excess zinc in
metallothionein.
The pancreas uses
zinc to make digestive
enzymes and secretes
them into the intestine.
If the body
Zinc is not absorbed
does not
and is excreted in shed
need zinc
intestinal cells instead.
Thus, zinc absorption is
reduced when the body
does not need zinc.
If the body
needs zinc
Metallothionein releases
zinc to albumin and
transferrin for transport
to the rest of the body.
Stepped Art
Enteropancreatic circulation of zinc.
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
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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
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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
Spaghetti pasta
1 oz (110 kcal)
½ c cooked (99 kcal)
Grains
Grains
Tortilla, flour-
1 10"-round (234 kcal)
Grains
0.1
0.5
0.6
Broccoli
Carrots
½ c cooked (22 kcal)
½ c shredded raw (24 kcal)
Vegetables
Vegetables
0.4
0.1
Potato
1 medium baked w/skin (133 kcal)
Vegetables
Tomato juice
¾ c (31 kcal)
Vegetables
Banana
1 medium raw (109 kcal)
Fruits
Orange
1 medium raw (62 kcal)
Fruits
Strawberries
½ c fresh (22 kcal)
Fruits
0.1
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
Cottage cheese
1½ oz(171 kcal)
½ c low-fat 2% (101 kcal)
Milk and milk products
Milk and milk products
Pinto beans
½ c cooked ( 1 17 koal)
Legumes, nuts, seeds
1.4
0.7
1
Peanut butter
2 lbs (188 koal)
Legumes, nuts, seeds
1
Sunflower seeds
1 oz dry (165 kcal)
Legumes, nuts, seeds
Tofu (soybean curd)
½ c (76 kcal)
Legumes, nuts, seeds
1.5
0.9
Ground beef, lean
3 oz broiled (244 kcal)
Meats, poultry, seafood
Chicken breast
3 oz roasted (140 kcal)
Meats, poultry, seafood
Tuna, canned in water
3 oz (99 kcal)
Meats, poultry, seafood
Egg
1 hard cooked (78 kcal)
Meats, poultry, seafood
0.5
0.4
0.2
4.2
0.9
0.8
0.6
Excellent, and sometimes unusual, sources:
Oysters
3 oz cooked (139 kcal)
Meats, poultry, seafood
Sirloin steak, lean
3 oz broiled (172 kcal)
Meats, poultry, seafood
12+
5.7
Crab
3 oz cooked (94 kcal)
Meats, poultry, seafood
4.8
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Iodine
• GI tract converts iodine in food to iodide
• Iodide: readily absorbed by the body
• Roles in the body
• Part of thyroid hormones that regulate:
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•
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•
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Body temperature
Metabolic rate
Reproduction and growth
Blood cell production
Nerve and muscle function
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Iodine Deficiency
• Thyroid hormone production
declines
• Increased secretion of thyroidstimulating hormone (TSH)
• Cells of thyroid expand: goiter
• Goitrogen
• Preventable mental retardation
and brain damage
• Cretinism
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Iodine Toxicity and Sources
• Toxicity
• Interferes with thyroid
function
• Enlarges thyroid gland
• Goiter in an infant
• UL
• Recommendations
• Sources
• Seafood
• Iodized salt
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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
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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
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Selenium Sources
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•
Found in soil
Meats, milk, and eggs
Brazil nuts
Recommendations
• RDA
• Amount needed to maximize glutathione
peroxidase activity
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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
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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
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Copper Sources
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Legumes
Whole grains
Nuts
Shellfish
Seeds
Water delivered through copper plumbing
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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
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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
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Fluoride
• Found in bones and teeth
• Fluorapatite
• Dental caries
• Sources
• Drinking water
• Most bottled waters lack
fluoride
• Tea and fish
• Toxicity: fluorosis
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Chromium
• Roles in the body
• 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
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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
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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
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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
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Phytochemicals
and Functional
Foods
Highlight 13
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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
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Phytochemicals and Cancer
• Protect against DNA
damage
• Soybeans
• Phytoestrogens
• Tomatoes
• Lycopene
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Phytochemicals and
Heart Disease
• Flavonoids
• Food sources
• Heart-protection factors
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Carotenoids
Plant sterols
Lignans
Defending against other diseases
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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
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The Colors of Foods Rich in
Phytochemicals
Red
Anthocyanins
Lycopene
Beets
Cherries
Cranberries
Pink grapefruit
Pomegranates
Radicchio
Radishes
Raspberries
Red apples
Red peppers
Red potatoes
Rhubarb
Strawberries
Tomatoes
Watermelon
White-Brown
Orange-Yellow
Allicin
Allyl sulfides
Bananas
Brown pears
Cauliflower
Chives
Dates
Garlic
Ginger
Leeks
Mushrooms
Onions
Parsnips
Shallots
Turnips
Beta-carotene
Limonene
Apricots
Cantaloupe
Carrots
Lemons
Mangoes
Nectarines
Oranges
Papayas
Peaches
Persimmons
Pineapple
Pumpkin
Rutabagas
Squash
Sweet potatoes
Tangerines
Yellow peppers
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Blue-Purple
Anthocyanins
Ellagic acid
Phenolics
Black currants
Blackberries
Blueberries
Dried plums
Eggplant
Elderberries
Plums
Purple figs
Purple peppers
Raisins
Purple cabbage
Purple grapes
Green
Beta-carotene
Lutein
Indoles
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
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