• Minerals that comprise < 0.01% of the body weight
• Needed in concentrations of 1 PPM (part per million) or less; < 100 mg needed per day
• RDAs have been established for 6 of these elements
• Iron, zinc, copper, iodine, selenium, and molybdenum
• Adequate intakes have been estimated for three
• Manganese, fluoride, chromium
• Many are involved as cofactors in enzymes

• Ferric (3+) and ferrous (2+) forms the only oxidation states found in the body and in food.
• Food forms are either heme or non-heme iron
• Heme forms (derived from hemoglobin and myoglobin) are found mostly in animal products
• Non-heme forms are principally found in plants and require more digestion prior to absorption; supplements are generally nonheme iron
• Many foods are fortified with iorn including flour, corn meal, and rice.
Table 12-2, p. 419

“Good” chelators:
Acids (ascorbic, citric, tartaric); sugars; meat products; mucin
“Inhibitors”: polyphenols such as those found in coffee and tea; oxalic acid; phytates; EDTA; calcium, zinc, manganese, nickel
Fig. 12-2, p. 421

Storage = liver, bone marrow, spleen p. 422

Cellular iron influences the synthesis of apoferritin at the translation level.
Release of iron from stores requires mobilization of Fe3+ and the use of reducing substances such as riboflavin, niacin, and/or vitamin C .
Uptake by tissues depends on the transferrin saturation level and the presence of a tranferrin receptor
(TfR2) on the cell
Fig. 12-4, p. 426

• Energy Production
• In heme proteins - hemoglobin, myoglobin, cytochromes, In iron-sulfur proteins several in electron transport chain, aconitase and ferrochelatase
• monooxygenases, dioxygenases, and oxidases,
• aconitase (krebs cycle)
• Peroxidases
• oxidoreductases
• Ribonucleotide reductase
• Glycerolphosphate dehydrogenase
Fig. 12-5, p. 428

Daily needs cannot be met by absorbed iron. Therefore, it is highly conserved and recycled.
Losses are from GI tract, skin, kidney
Fig. 12-6, p. 432

Deficiency: Iron Deficiency and Iron Deficiency Anemia
Fig. 12-7, p. 433

Toxicity: Hemochromatosis or iron overload

Zinc
• Found in all organs and tissues; highest in bone, liver, kidney, muscle and skin
• Can exist in different valence states but in the body is always found in its divalent form
(Zn2+)
• Found in many sources, but zinc from plant sources is lower in content and not as easily absorbed as Zn associated with meat.
Table 12-3, p. 436

Enhancers of absorption: citric acid, picolinic acid, histidine, cysteine, glutathione, low zinc status
Inhibitors: phytate, oxalate, polyphenols, fibers, folic acid, divalent cations
Fig. 12-8, p. 438

Fig. 12-10, p. 440

Involved in at least 70 and probably as many as 200 different reactions. Is a part of more enzyme systems than all the other trace elements combined.
Table 12-4, p. 441

Table 12-5, p. 446

Fig. 12-12, p. 447

Fig. 12-13, p. 450

p. 451a

p. 451b

p. 452a

p. 452b

p. 452c

Fig. 12-14, p. 456

Fig. 12-15, p. 457

Fig. 12-16, p. 458

p. 459a

p. 459b

p. 459c

p. 460a

p. 460b

Fig. 12-17, p. 464

Fig. 12-18, p. 464

Fig. 12-19, p. 465

Fig. 12-20, p. 468

Fig. 12-21, p. 469

p. 470

Fig. 12-22, p. 470

Fig. 12-23, p. 471

p. 472

Table 12-6, p. 473

p. 474

Fig. 12-24, p. 478

p. 478

Fig. 12-25, p. 479

Fig. 12-25a, p. 479

Fig. 12-25b, p. 479

Table 12-7, p. 481

Table 12-1a, p. 418

Table 12-1, p. 418

Table 12-1b, p. 418