1. Chapter 14: Trace Minerals
Objectives
Describe the major functions of copper, fluoride, iodine, iron, selenium, and zinc in the body
Identify the general properties of trace minerals
Describe how the use of iodine and the production of thyroid hormone are controlled
Describe the symptoms of deficiency and toxicity of copper, fluoride, iodine, iron, selenium, and zinc
Identify at least two dietary sources of copper, iodine, iron, selenium, and zinc
Discuss the dietary sources of heme and non-heme iron and the factors that affect their absorption

2. The Goiter Belt
During World War I, 64.4% of people in Michigan showed signs of a goiter
Soils deficient in iodine
Added iodine to table salt
Iodine deficiency remains one of the most important public health issues globally
In World War I many men, women, and children of the Goiter Belt (as many as 64.4% of people in some parts of Michigan) were showing signs of a goiter, an enlargement of the thyroid gland. Many military recruits were too unhealthy to serve in the war efforts. The soils of the Great Lakes, Appalachians, and Northwestern regions of the United States are poor in the trace mineral iodine, which the body needs to make thyroid hormones.

3. Trace Minerals
Micro-minerals are iodine, iron, zinc, copper, selenium, molybdenum, fluoride, manganese, and chromium
Need significantly less than major minerals
Daily requirement <100 mg/day
Critical for health

4. Properties of Trace Minerals
Bioavailability influenced by
Form of the food
Nutrition status
Age
Pregnancy
Safe range of intake narrow
Intake above the UL through supplements
It’s rare to overconsume minerals through food alone, but using supplements can result in intakes above the UL and potentially dangerous adverse effects. Eating a balanced and varied diet can provide enough trace minerals.

5. Properties of Trace Minerals

6. Iodine (I) Foods depend upon iodine content of the soil
U.S. salt company began to add iodine to salt
15% of U.S. salt intake iodized
Sources of iodine
Seafood
Milk
Processed grains

7. Iodine Functions Component of thyroid hormone
Regulates energy metabolism and protein synthesis
Critical role in the development of the fetal skeleton and brain
Thyroid-stimulating hormone (TSH)
Secreted from the pituitary gland
Regulates the thyroid

8. Iodine Functions

9. Iodine Deficiency Hypothyroidism Cretinism Slow metabolic rate Goiter
Mental retardation, deafness, stunted growth, and other abnormalities
Mild forms of iodine deficiency in pregnancy can affect neurological development

10. Iodine Recommended Intakes
RDA for >19 years of age: 150 mcg

11. Iodine Excessive Intake
UL = 1,100 mcg
Excessive intake can cause : goiter, hypothyroidism, and elevated TSH

12. Iron (Fe) Types Heme iron Non-heme iron Most abundant trace mineral
Hemoglobin
Myoglobin
Non-heme iron
Most abundant trace mineral
Component of many enzymes
Important in reproduction, growth, and healing
The World Health Organization considers iron deficiency to be the number one nutritional disorder in the world, affecting as much as 80% of the world’s population in both developing and industrialized nations.

13. Iron in the Body
The World Health Organization considers iron deficiency to be the number one nutritional disorder in the world, affecting as much as 80% of the world’s population in both developing and industrialized nations.

14. Iron in the Body
The World Health Organization considers iron deficiency to be the number one nutritional disorder in the world, affecting as much as 80% of the world’s population in both developing and industrialized nations.

15. Iron Sources Food sources Absorption
Heme in red meats, poultry, and fish
Non-heme in plant foods
Lentils, beans, dried fruits, and grain products
Absorption
Increased by vitamin C, acid, and meat
Decreased by soy protein, phytates, and polyphenols, as well as calcium intake
Iron balance in the body is regulated by iron absorption, storage, release, and transport.

16. Iron Deficiency Iron deficiency anemia Symptoms Caused by blood loss
Insufficient iron intake
High-risk groups
Children, pregnant, and menstruating women
Symptoms
Tired, out of breath, poor performance, and slow cognitive and social development

17. Iron Recommendations RDA for men >19 years of age = 8 mg
RDA for women 19 to 50 years of age = 18 mg
Assumes 75% heme iron
RDA for vegetarians doubled (non-heme iron)
Athletes have a 30% higher requirement

18. Iron Recommendations

19. Iron Recommendations UL for men and women >19 years of age = 45 mg
Cause gastrointestinal distress
Diarrhea, constipation, nausea, vomiting
Iron toxicity causes apathy, fatigue, liver damage, and immune problems
Iron poisoning
Unintentional death in children
Nausea, vomiting, diarrhea, rapid heartbeat, dizziness, shock, and confusion

20. Zinc (Zn) Dr. Prasad Diets heavy in bread and grains
High in phytates that bind iron and zinc
Growth retardation and delayed sexual maturation

21. Zinc (Zn) Cofactor for over 900 enzymes
Required for almost every essential process in the body
Regulation of protein synthesis
Reproduction
Cell division
Growth and development
Immune responses
Neurological functions

22. Zinc Deficiency Symptoms At-risk groups
Impaired immune function
Appetite loss and weight loss
Delayed sexual maturation
Stunted growth
Severe deficiency can result in hair loss, diarrhea, infertility in males, and impaired neurological and behavioral function
At-risk groups
Alcoholics
Vegetarians
Elderly
Alcohol decreases absorption and increases excretion
Phytates inhibit absorption
About 13% of the U.S. population is at risk for zinc deficiency.

23. Zinc Recommendations RDA for males >19 years of age = 11 mg
RDA for females >19 years of age = 8 mg
Vegetarians’ needs are doubled
UL = 40 mg
Excessive intake can lead to nausea, vomiting, diarrhea, copper deficiency, reduced immune function, and altered iron function

24. Zinc Sources

25. Zinc Sources

26. Copper (Cu) Functions Cofactor in oxygen-dependent enzymes
Energy metabolism
Formation of connective tissues
Regulation of iron storage and transport
Antioxidant functions
May slow progression of age-related macular degeneration

27. Copper Deficiency Rare in the United States
Mostly secondary to other factors
Malabsorption from other conditions
Gastric bypass surgery
Excessive zinc intake
Symptoms
Anemia
Impaired immune response
Osteoporosis

28. Copper Recommendations
RDA = 900 mcg/day

29. Selenium (Se) Functions Cofactor of several antioxidant enzymes
Activation of thyroid hormone
Essential for normal growth, development, and metabolism

30. Selenium Deficiency Deficiency
Low selenium status increases risk for a particular form of heart disease
May increase risk of some cancers
Decreases immune function

31. Selenium Recommendations
RDA for adults = 55 mcg
UL = 400 mcg
Hair and nail brittleness and loss
Single high dose fatal
Food sources
Meats and cereals
Plant food sources vary due to soil concentrations
Brazil nuts
Absorption not regulated

32. Other Trace Minerals Chromium (Cr) Fluoride Manganese Molybdenum
Enhances the action of insulin
Fluoride
Hardens the enamel of our teeth
Prevents of dental caries
Manganese
Cofactor for enzymes in antioxidant function, energy metabolism, bone development, and neurotransmitter production
Molybdenum
Cofactor for four enzymes in metabolism

33. Ultratrace Minerals Intake requirements <1 mcg/day
Food only safe source of intake
Specific biological or physiological functions not yet identified
Not currently classified as essential
Animal data suggest these may be important
Arsenic (As)
Boron (B)
Nickel (N)
Silicon (Si)
Vanadium (V)

34. Summary
Trace minerals are essential nutrients required in very small amounts in human nutrition and include chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc
Trace minerals have vital roles in the body, such as participating as cofactors in numerous chemical reactions
Found in both plant and animal foods, the actual bioavailability of trace minerals is influenced by many factors
Trace mineral deficiencies can have varied, yet serious, consequences particularly of concern in pregnant woman and growing children

35. Summary (Cont’d)
Trace minerals are found across all food groups; thus, sufficient intake can generally be achieved by consuming a varied and balanced diet
Ultratrace minerals are not currently classified as essential nutrients but may have important values in the body; they are arsenic, boron, nickel, silicon, and vanadium