The Trace Minerals--An Overview
►
Trace minerals are needed in very small
(trace) quantities in the human body. They perform many essential functions important to health.
►
Toxic levels can easily be reached with the use of supplements.
►
Humans can get the amounts of trace minerals needed by consuming a wide variety of foods.

The Trace Minerals--An Overview
►
Food Sources
 Depends on soil and water composition
 Depends on processing
 Bioavailability
 Wide variety of unprocessed foods

The Trace Minerals--An Overview
►
Deficiencies
 Severe deficiencies of some minerals are easy to recognize, while others can be difficult to diagnose.
 Mild deficiencies are easily overlooked.
 Deficiencies have wide-reaching effects.
 Deficiencies affect all ages, but in children, they can affect growth.

The Trace Minerals--An Overview
►
Toxicities
 Do not exceed Tolerable Upper Intake Levels.
 FDA does not limit amounts in supplements.
 Do not exceed 100% Daily Values.
►
Interactions
 Common and coordinated to meet body needs
 Can lead to nutrient imbalances

Iron
►
►
►
►
►
Iron is an essential nutrient found in the body as a part of hemoglobin and myoglobin.
Iron is used for energy metabolism and enzyme activity.
Special proteins assist with iron absorption, transport, and storage.
Both iron deficiency and iron toxicity cause damage so balance is important.
Heme iron is better absorbed but nonheme iron absorption can be enhanced.

Iron Roles in the Body
 Cofactor in oxidation-reduction reactions
 Utilization of energy in cell metabolism
 Part of the protein hemoglobin which carries oxygen in the blood
 Part of the protein myoglobin in the muscles which makes oxygen available for muscle contractions

Iron Absorption and Metabolism
 Iron Absorption
►
The protein ferritin stores iron in the mucosal cells lining the digestive tract.
►
Transfers iron to mucosal transferrin.
►
Transfers iron to blood transferrin
►
Transports iron to the cells
►
Excreted and replaced as needed

Iron in food
Mucosal cells in the intestine store excess iron in mucosal ferritin
(a storage protein).
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 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
Fig. 13-1, p. 443

Iron Absorption and Metabolism
 Heme and Nonheme Iron
►
Heme iron
 Found in foods that are from the flesh of animals (meat, poultry, and fish)
 Represents only 10% of a days iron consumption, but has an absorption rate of 25%
►
Nonheme iron
 Found in plant-derived and animal-derived foods
 Has an absorption rate of 17%

Only foods derived from animal flesh provide heme, but they also contain nonheme iron.
Key:
Heme
Nonheme
All of the iron in foods derived from plants is nonheme iron.
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%).
Stepped Art
Fig. 13-2, p. 444

Iron Absorption and Metabolism
 Absorption-Enhancing Factors
 MFP factor
 When nonheme iron is consumed with vitamin C at the same meal, absorption of iron increases.
 Citric acid and lactic acid from foods, HCl from the stomach, and sugars enhance nonheme iron absorption
.

Iron Absorption and Metabolism
 Absorption-Inhibiting Factors
►
Phytates and fibers from legumes, grains, and rice
►
Vegetable proteins in soybeans, legumes, and nuts
►
Calcium in milk
►
Tannic acid and other polyphenols in tea, coffee, grains, oregano, and red wine
 Dietary Factors Combined
►
Difficult to assess iron absorption with meal consumption
►
Most relevant factors are MFP factor and vitamin C in enhancing absorption and phytates in inhibiting absorption

Iron Absorption and Metabolism
►
Individual Variation
►
Dietary factors
►
Health status
►
Stage in life cycle
►
Iron status

Iron Absorption and Metabolism
►
Iron Transport and Storage
►
Surplus is stored in bone marrow, spleen, and liver
►
Hemosiderin is a storage protein used when concentrations of iron are extremely high.
►
Storing excess iron is a protective measure because iron can act as a free radical.

Iron Absorption and Metabolism
 Iron Recycling
►
The liver and spleen dismantle red blood cells and package iron into transferrin.
►
Transferrin carries iron in the blood .
►
Bone marrow incorporates iron into hemoglobin and stores iron as ferritin.
►
Iron-containing hemoglobin carries oxygen in the blood.
►
Iron is lost when bleeding occurs and through the GI tract.

Some losses via sweat, skin, and urine
Liver (and spleen) dismantles red blood cells, packages iron into transferrin, and stores excess iron in ferritin
(and hemosiderin).
Transferrin carries iron in blood.
Some iron delivered to myoglobin of muscle cells
Bone marrow incorporates iron into hemoglobin of red blood cells and stores excess iron in ferritin
(and hemosiderin).
Some losses if bleeding occurs
Iron-containing hemoglobin in red blood cells carries oxygen.
Stepped Art
Fig. 13-3, p. 445

Iron Deficiency
►
Iron deficiency is the most common nutrient deficiency.
 Iron-deficiency anemia can affect individuals in many stages of life.
 Vulnerable Stages of Life
►
Women in reproductive years due to menstruation
►
Pregnant women due to the needs of the infant, increases in blood volume, and loss of blood during the birthing process
►
Infants and young children due to rapid growth
►
Teenagers due to rapid growth in males and menstruation in females

Iron Deficiency
 Blood Losses
►
Can be from non-obvious sources such as a bleeding ulcer
►
Malaria and parasites
►
Giving a pint of blood results in a loss of about 2.5 mg iron.
►
Menstruation

Iron
►
Iron Deficiency
 Assessment of Iron Deficiency
►
Stage 1 – Iron stores diminish; measured by serum ferritin
►
Stage 2 – Transport iron decreases; measured by transferrin saturation
►
Stage 3 – Hemoglobin production declines; erythrocyte protoporphyrin accumulates and hematocrit declines. Hemoglobin and
hematocrit are late indicators of iron status.

Iron
►
Iron Deficiency
 Iron Deficiency and Anemia
►
Iron deficiency is when there is depletion of the body’s iron stores.
►
Iron-deficiency anemia is the severe depletion of iron stores. Also called microcytic (small) hypochromic (pale) anemia.
►
Symptoms include fatigue, weakness, headaches, apathy, pallor and poor resistance to cold temperatures.

Iron
►
Iron Deficiency
 Iron Deficiency and Behavior
►
Energy metabolism is impaired.
►
Neurotransmitter synthesis is reduced.
►
Physical work capacity and mental productivity are reduced.
►
Symptoms of a deficiency may be confused with behavioral issues.

Iron
►
Iron Toxicity
 Iron Overload
►
Hemochromatosis is generally a genetic disorder that enhances iron absorption.
►
Iron overload can also be caused by:
 Repeated blood transfusions
 Massive doses of supplemental iron
 Rare metabolic disorders

Iron
►
Iron Overload
 Hemosiderosis may develop from excessive iron where there are large deposits of hemosiderin in the liver, heart, joints, and other tissues.
 Symptoms of iron overload include apathy, lethargy, and fatigue.
 Problems include liver tissue damage and infections.
 Higher risk of diabetes, liver cancer, heart disease, and arthritis
 More common in men then in women

Iron
►
Iron Toxicity
 Iron and Heart Disease – may be a link to high iron stores
 Iron and Cancer – may be a link with free radical activity resulting in damage to DNA
 Iron Poisoning
►
UL for adults: 45 mg/day
►
Accidental supplement poisoning in children
►
Symptoms include nausea, vomiting, diarrhea, constipation, rapid heartbeat, weak pulse, dizziness, shock, and confusion

Iron
►
Iron Recommendations and Sources
 Recommended Iron Intakes (2001 RDA)
►
RDA Men: 8 mg/day for adults 19-50 years of age
►
RDA Women: 18 mg/day for adults 19-50 years of age
►
RDA Women: 8 mg/day for adults over 51 years of age
►
Vegetarians need 1.8 times as much iron because of low bioavailability.

Iron
►
Iron Recommendations and Sources
 Iron in Foods
►
Red meats, fish, poultry, and shellfish
►
Eggs
►
Legumes
►
Grain products (whole-grain, enriched, and fortified breads and cereals)
►
Dark greens and dried fruits
 Iron-Enriched Foods
►
Often added to grain foods
►
Not absorbed as well

Iron
►
Iron Recommendations and Sources
 Maximizing Iron Absorption
►
Bioavailability is high in meats, fish, and poultry.
►
Bioavailability is intermediate in grains and legumes.
►
Bioavailability is low in vegetables.
►
Combined effect of enhancing and inhibiting factors

Iron
►
Iron Contamination and Supplementation
 Contamination Iron
►
Iron cookware takes up iron salts.
►
Acidic foods and long cooking times increase uptake of iron salts.
 Iron Supplements
►
Best absorbable form is ferrous sulfate or an iron chelate
►
Take on empty stomach and with liquids other than milk, tea, or coffee
►
Vitamin C enhances food iron absorption , not supplement absorption.
►
Side effect of constipation

Zinc
►
►
►
►
►
►
Zinc is important in a multitude of chemical reactions in the body.
The best sources of dietary zinc are protein-rich foods .
Zinc from pancreatic secretions is also available for absorption.
Phytates and fiber can bind zinc, therefore limiting absorption.
A special binding protein monitors the absorption of zinc.
Zinc deficiency symptoms include growth retardation and sexual immaturity.

Zinc
►
Zinc Roles in the Body
 Supports the work of metalloenzymes
►
Helps to make parts of DNA and RNA
►
Manufactures heme for hemoglobin
►
Assists in essential fatty acid metabolism
►
Releases vitamin A from liver stores
►
Metabolizes carbohydrates
►
Synthesizes proteins
►
Metabolizes alcohol
►
Disposes of damaging free radicals

Zinc
►
Zinc Roles in the Body
 Involved in growth, development , and immune function
 Affects platelets in blood clotting and wound healing
 Needed to produce the retinal form of vitamin A
 Affects thyroid hormone function
 Influences behavior and learning performance
 Taste perception
 Wound healing
 Sperm development
 Fetal development

Zinc
►
Zinc Absorption and Metabolism
 Zinc Absorption
►
Rate of absorption depends on zinc status; when more is needed, more will be absorbed.
►
Phytates and fiber bind zinc and reduce absorption.
►
Metallothionein is a special protein that holds zinc in storage.

Zinc
►
Zinc Absorption and Metabolism
 Zinc Recycling
►
Enteropancreatic circulation – travels from the pancreas to the intestines and back
►
Losses occur in the feces, urine, shedding of skin, hair, sweat, menstrual fluids, and semen.

Zinc in food
The pancreas uses zinc to make digestive enzymes and secretes them into the intestine.
Mucosal cells in the intestine store excess zinc in metallothionein.
If the body needs zinc
If the body does not need zinc
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.
Stepped Art
Fig. 13-6, p. 453

Zinc
►
Zinc Absorption and Metabolism
 Zinc Transport
►
Transported by the protein albumin
►
Binds to transferrin
►
Excessive iron and copper can lead to a zinc deficiency and excessive zinc can lead to an iron and copper deficiency.

Zinc
►
Zinc Deficiency
 Not widespread
 Occurs in pregnant women, young children, the elderly, and the poor
 Symptoms of deficiency
►
Growth retardation
►
Delayed sexual maturation
►
Impaired immune function
►
Hair loss, eye and skin lesions
►
Altered taste, loss of appetite, and delayed wound healing

Zinc
►
Zinc Toxicity
 UL for Adults: 40 mg/day
 Symptoms
►
Loss of appetite
►
Impaired immunity
►
Low HDL
►
Copper and iron deficiencies
►
Vomiting and diarrhea
►
Exhaustion
►
Headaches

Zinc
►
►
Zinc Recommendations and Sources
 Recommended intakes (2001 RDA)
►
RDA Men: 11 mg/day
►
RDA Women: 8 mg/day
 Zinc in foods
►
Shellfish, meats, poultry, milk, and cheese
►
Whole grains and legumes
Zinc Supplementation
 Developing countries use zinc to reduce incidence of disease and diarrhea.
 Zinc lozenges for the common cold are controversial and inconclusive.

Iodine
►
Iodide is an essential component of the thyroid hormone that helps to regulate metabolism.
►
Iodine deficiency can cause simple goiter and cretinism.
►
The iodization of salt has greatly reduced iodine deficiency in the United States and
Canada.

Iodine
►
Iodide Roles in the Body
 Component of two thyroid hormones (T
3
T
4
) and
 Regulates body temperature, growth, development, metabolic rate, nerve and muscle function, reproduction, and blood cell production.

Iodine
►
Iodine Deficiency
 Simple goiter is the enlargement of the thyroid gland caused by iodine deficiency. Goiter is enlargement of the thyroid gland due to malfunction of the gland, iodine deficiency or overconsumption of goitrogens.
 Goitrogen (antithyroid) overconsumption – naturally occurring in cabbage, spinach, radishes, rutabaga, soybeans, peanuts, peaches, and strawberries.
 Cretinism is a congenital disease characterized by mental and physical retardation and commonly caused by maternal iodine deficiency during pregnancy.

Iodine
►
Iodine Toxicity
 UL 1100 μg/day
 Symptoms include underactive thyroid gland, elevated TSH, and goiter.
 Supplement use, medications, and excessive iodine from foods

Iodine
►
Iodine Recommendations and Sources
 Recommendations (2001 RDA) – Adults: 150
μg/day
 Sources
►
Iodized salt
►
Seafood
►
Bread and dairy products
►
Plants grown in iodine-rich soils
►
Animals that feed on plants grown in iodine-rich soils

Selenium
►
Selenium is an antioxidant nutrient associated with protein foods.
►
It may provide some protection against certain types of cancer.
►
Selenium Roles in the Body
 Defends against oxidation
 Regulates thyroid hormone

Selenium
►
Selenium Deficiency
 Keshan disease – a pre-disposition to heart disease where a virus causes the cardiac tissue to become fibrous
 Prevalent in regions of China because the soil is low in selenium

Selenium
►
Selenium and Cancer
 May protect against certain forms of cancer
 Inconclusive evidence and more research is needed
 Food sources are better than supplements.

Selenium
►
Selenium Recommendations and Sources
 Recommendations (2000 RDA) – Adults: 55
μg/day
 Sources include seafood, meat, whole grains, and vegetables (depends on soil content).

Selenium
►
Selenium Toxicity
 UL for Adults: 400 μg/day
 Symptoms
►
Loss and brittleness of hair and nails
►
Skin rash, fatigue, irritability, and nervous system disorders
►
Garlic breath odor

Copper
►
Copper is a component of several enzymes associated with oxygen or oxidation.
►
Copper deficiency is rare.
►
There are some diseases associated with excessive intakes.
►
Food sources of copper include legumes, whole grains, and seafood.

Copper
►
Copper Roles in the Body
 Absorption and use of iron in the formation of hemoglobin
 Part of several enzymes
 Some copper-containing enzymes are antioxidants.
 Required for many metabolic reactions

Copper
►
Copper Deficiency and Toxicity
 Deficiency is rare in the U.S.; however, symptoms include anemia and bone abnormalities.
 In Menkes disease, copper cannot be released into the circulation.
 Toxicity
►
UL for Adults: 10,000 μg/day (10 mg/day)
►
In Wilson’s disease, copper builds up in the liver and brain.
►
Excessive intake from supplements can cause liver damage.

Copper
►
Copper Recommendations and Sources
 Recommendations (2001 RDA) – Adults: 900
μg/day
 Sources
►
Seafood, nuts, seeds and legumes
►
Whole grains
►
In houses with copper plumbing, water can be a source.

Manganese
►
►
►
►
Manganese is a cofactor for several enzymes involved in bone formation and various metabolic processes.
Deficiencies are rare and toxicities are associated with environmental contamination.
Manganese is found in many foods.
Manganese Roles in the Body
 Cofactor for several enzymes
 Assists in bone formation
 Pyruvate conversion

Manganese
►
Manganese Deficiency and Toxicity
 Deficiency symptoms are rare.
 Phytates, calcium and iron limit absorption.
 Toxicity occurs with environmental contamination.
 UL for Adults: 11 mg/day
 Toxicity symptoms include nervous system disorders.

Manganese
►
Manganese Recommendations and Sources
 Recommendations (2001 AI)
►
AI Men: 2.3 mg/day
►
AI Women: 1.8 mg/day
 Sources
►
Nuts
►
Whole grains
►
Leafy vegetables
►
Tea

Fluoride
►
Fluoride makes bones stronger and teeth more resistant to decay.
►
The use of fluoridated water can reduce dental caries.
►
Excess fluoride causes fluorosis—the pitting and discoloration of teeth.

Fluoride
►
Fluoride Roles in the Body
 Formation of teeth and bones
 Helps to make teeth resistant to decay
 Fluorapatite is the stabilized form of bone and tooth crystals
 Fluoride and Dental Caries
►
Widespread health problem
►
Leads to nutritional problems due to issues with chewing

Fluoride
►
Fluoride and Toxicity
 Tooth damage called fluorosis – irreversible pitting and discoloration of the teeth
 UL for Adults: 10 mg/day
 Prevention of fluorosis
►
Monitor fluoride content of local water supply.
►
Supervise toddlers during tooth brushing.
►
Watch quantity of toothpaste used (pea size) for toddlers.
►
Use fluoride supplements only if prescribed by a physician.

Fluoride
►
Fluoride Recommendations and Sources
 Recommendations (1997 AI)
►
AI Men: 3.8 mg/day
►
AI Women: 3.1 mg/day
 Sources
►
Fluoridated drinking water
►
Seafood and tea

Chromium
►
Chromium is an essential nutrient that enhances insulin’s action.
►
It is widely available in unrefined foods.
►
Chromium Roles in the Body
 Enhances insulin action
 Low chromium levels can result in elevated blood sugar levels.
 Glucose tolerance factors (GTF) are small organic compounds that enhance insulin’s action and some contain chromium.

Chromium
►
►
Chromium Recommendations and Sources
 Recommendations (2001 AI)
►
AI Men: 35 μg/day
►
AI Women: 25 μg/day
 Sources
►
Meat, especially liver
►
Whole grains
►
Brewer’s yeast
Chromium Supplements
 Claims about reducing body fat and improving muscle strength remain controversial.

Molybdenum
►
Molybdenum is a cofactor in several enzymes.
►
It is needed in minuscule amounts.
►
It is available in legumes, grains, and organ meats.
►
Molybdenum functions as a cofactor for several enzymes.
►
No deficiency symptoms
►
No reported toxicity symptoms in humans

Molybdenum
►
Recommendations (2001 RDA)
 Adults: 45 μg/day
 UL Adults: 2 mg/day
►
Food sources include legumes, grains, and organ meats.

Other Trace Minerals
►
Much of the research on other trace minerals is from animal studies.
►
Humans need very small amounts.
►
Determining exact needs, functions, deficiencies, and toxicities is difficult.
►
Some key roles of these other trace minerals have been identified.

Other Trace Minerals
►
Nickel is a cofactor for certain enzymes.
►
Silicon is used in bone and collagen formation.
►
Vanadium is for growth, development, and normal reproduction.
►
►
Cobalt is a key component of vitamin B
12
.
Boron may be key in brain activities.
►
Arsenic is useful in some types of leukemia.

Contaminant Minerals
►
Contaminate minerals are also called heavy metals.
►
These include mercury, lead, and cadmium .
►
These minerals enter the food supply through soil, water, and air pollution.
►
They disrupt body processes and impair nutrition status.

Contaminant Minerals
►
Lead toxicity symptoms in children
 Learning disabilities in children
 Low IQ
 Behavior problems
 Slow growth
 Dental caries
 Iron-deficiency anemia
 Sleep disturbances like night walking, restlessness, and head banging
 Nervous system disorders and seizures
 Slow reaction time and poor coordination
 Impaired hearing

Contaminant Minerals
►
Lead toxicity symptoms in adults
 Hypertension
 Reproductive complications
 Kidney failure

Phytochemicals and Functional
Foods
►
Phytochemicals are nonnutrient compounds.
►
Only a few of the thousands of phytochemicals have been researched.
►
There are many questions and few answers about their role in human health.
►
Foods that provide health benefits beyond those of nutrients are now called functional foods.
►
Some have an identified role in disease prevention.

The Phytochemicals
►
The phytochemicals give foods taste, aroma, color, and other characteristics.
►
Defending against Cancer
 Phytoestrogens mimic estrogen
►
Found in soybeans, legumes, flaxseeds, whole grains, fruits and vegetables
►
Antioxidant activity
►
Slow the growth of breast and prostrate cancer
►
Supplements may stimulate the growth of cancers that depend upon estrogen.

The Phytochemicals
►
Defending against Cancer
 Lycopene
►
Powerful antioxidant
►
Inhibits the growth of cancer cells
►
Found in tomatoes and cooked tomato products, apricots, guava, papaya, pink grapefruits, and watermelon
 Five servings of fruits and vegetables are recommended every day.

The Phytochemicals
►
Defending against Heart Disease
 Flavonoids in foods
►
Powerful antioxidants
►
Protect against LDL cholesterol oxidation and reduce blood platelet stickiness
►
Lowers risk of chronic diseases
►
Found in whole grains, legumes, soy, vegetables, fruits, herbs, spices, teas, chocolate, nuts, olive oil, and red wines

The Phytochemicals
►
Defending against Heart Disease
 Carotenoids in foods especially lutein and lycopene
►
Lower risk of heart disease
►
Found in fruits and vegetables
 Phytosterols
►
May protect against heart disease
►
Inhibit cholesterol absorption
►
Lower blood pressure
►
Act as antioxidants
►
Found in soybeans and other vegetables
►
Lignans, found in flax seed, are converted to phytosterols by intestinal bacteria.

The Phytochemicals
►
The Phytochemicals in Perspective
 Difficult to assess one food and its benefits alone
 Actions of phytochemicals are complementary and overlapping

Functional Foods
►
Foods as Pharmacy
 Margarine enhanced with a phytosterol may lower cholesterol.
 May be more useful in prevention and mild cases of disease.
 Drugs are used for severe cases of disease.

Functional Foods
►
Unanswered Questions
 Research is lagging behind food manufacturers.
 Consumer questions to ask
►
Does it work?
►
How much does it contain?
►
Is it safe?
►
Is it healthy?

Functional Foods
►
Future Foods
 Use of gene research
 Can we design foods to meet exact health needs of each individual?
 Can farmers grow the “perfect” foods?