1. Trace Minerals

2. 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.

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

4. 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.

5. 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

6. 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.

7. 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

8. Iron Absorption and Metabolism
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

9. If the body does not need iron
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
Figure 13.1: Iron Absorption.
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

10. 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%

11. All of the iron in foods derived from plants is nonheme iron.
Only foods derived from animal flesh provide heme, but they also contain nonheme iron.
Heme accounts for about 10% of the average daily iron intake, but it is well absorbed (about 25%).
Key:
Heme
Nonheme
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.
Figure 13.2: Heme and Nonheme Iron in Foods.
Stepped Art
Fig. 13-2, p. 444

12. 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.

13. 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

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

15. 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.

16. 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.

17. Transferrin carries iron in blood.
Some losses via sweat, skin, and urine
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).
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.
Figure 13.3: Animated! Iron Recycled in the Body.
Once iron enters the body, most of it is recycled. Some is lost with body tissues and must be replaced by eating iron-containing food.
Stepped Art
Fig. 13-3, p. 445

18. 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

20. 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

21. 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.

22. 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.

23. 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.

24. 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

25. 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

26. 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

27. Iron Iron Recommendations and Sources
Recommended Iron Intakes (2001 RDA)
RDA Men: 8 mg/day for adults years of age
RDA Women: 18 mg/day for adults 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.

28. 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

30. 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

31. 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

32. 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.

33. 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

34. 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

35. 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.

36. 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.

37. If the body does not need zinc Zinc is not absorbed
Zinc in food
The pancreas uses zinc to make digestive enzymes and secretes them into the intestine.
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.
Mucosal cells in the intestine store excess zinc in metallothionein.
If the body needs zinc
Metallothionein releases zinc to albumin and transferrin for transport to the rest of the body.
Figure 13.6: Animated! Enteropancreatic Circulation of Zinc.
Some zinc from food is absorbed by the small intestine and sent to the pancreas to be incorporated into digestive enzymes that return to the small intestine. This cycle is called the enteropancreatic circulation of zinc.
Stepped Art
Fig. 13-6, p. 453

38. 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.

39. 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

41. 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

42. Zinc Zinc Recommendations and Sources Zinc Supplementation
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.

44. 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.

45. Iodine Iodide Roles in the Body
Component of two thyroid hormones (T3 and T4)
Regulates body temperature, growth, development, metabolic rate, nerve and muscle function, reproduction, and blood cell production.

46. 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.

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

49. 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

50. 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

51. 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

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

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

55. 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

56. 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.

57. 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

58. 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.

59. 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.

60. 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

61. 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.

62. 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

64. 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.

65. 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

67. 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.

69. 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

70. 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.

71. Chromium Chromium Recommendations and Sources Chromium Supplements
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.

72. 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

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

74. 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.

75. 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 B12.
Boron may be key in brain activities.
Arsenic is useful in some types of leukemia.

76. 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.

77. 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

78. Contaminant Minerals Lead toxicity symptoms in adults Hypertension
Reproductive complications
Kidney failure

79. Phytochemicals and Functional Foods

81. 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.

82. 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.

84. 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.

86. 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

87. 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.

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

90. 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.

91. 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?

92. 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?