123 Unit 5: Trace Elements

• Trace elements


  Naturally occurring inorganic substances required in humans in amounts <100 mg/day
• Trace elements


  • They are essential components of biological structures and have an important effect on and play a key role in a variety of the processes necessary for life throughout mediate vital biochemical reactions
  • Excessive levels, a level higher than needed for biological functions, of these elements can be toxic for the body health
• Imbalances in the optimum levels of trace elements may adversely affect biological processes and are associated with many fatal diseases, such as cancers
• Efforts have been focused to attempt to advance understand of the relationship between heavy metal, trace elements, and their role in cancers
• Specific trace elements may be of value and may have prognostic significance in the early diagnosis, prognosis, and therapy evaluation of some diseases, especially various types of cancer
• Trace element


  • (in analytical chemistry) an element in a sample that has an average concentration of <100 parts per million (ppm) measured in atomic count or <100 µg/g
  • (in biochemistry) a dietary mineral that is needed in very minute quantities for the proper growth, development, and physiology of the organism
• Trace elements


  • They attract and facilitate conversion of substrate molecules to specific end products in enzyme reactions
  • They donate or accept electrons in redox reactions that are of primary importance in the generation and utilization of metabolic energy
  • They have structural roles and are responsible for the stability of important biological molecules
  • They have important actions throughout biological processes, for example, iron (Fe) which can bind, transport, and release oxygen in the body
• Excessive levels of trace elements can be toxic for the body health and may lead to many fatal diseases, such as cancers
• Zinc (Zn)


  A chemical element with symbol Zn and atomic number 30, the first element of group 12 of the periodic table, discovered by German chemist Andreas Sigismund Marggraf in 1746
• Zn is the second metal present in the human body (about 2.5 g), after Fe (about 4 g) but before copper (Cu) (about 0.2 g)
• Recommended daily amount (RDA) for Zn

  8 mg/day for women and 11 mg/day for men
• Foods rich in Zn

  • Wheat, brown rice, oats, lentils, soybeans, dried peas, black-eyed peas, lima beans, walnuts, peanuts, cashews, brazil nuts, many cheeses, any kind of liver, and animal flesh such as beef, lamb, chicken, turkey, and various fish and seafood
• Zn


  • It is an essential trace element that functions as a cofactor for certain enzymes involved in metabolism and cell growth, it is found in nearly 300 specific enzymes
  • It is involved in the metabolism of proteins, carbohydrates, lipids, and energy
  • It is vital for the healthy working of many of the body's systems and plays an essential role in numerous biochemical pathways
  • It is particularly important for healthy skin and is essential for a healthy immune system and resistance to infection
  • It plays a crucial role in growth and cell division where it is required for protein and DNA synthesis, in insulin activity, in the metabolism of the ovaries and testes, and in liver function
• Zn deficiency


  It may occur due to insufficient dietary intake, and it is a serious problem in many developing countries, ranked as the 5th leading risk factor in causing disease, especially diarrhea and pneumonia in children, which can lead to high mortality rates in these underdeveloped regions
• Other severe Zn deficiency symptoms include stunted growth and impaired development of infants, children, and adolescents, impaired cognitive function, impaired immune function, behavioral problems, memory impairment, and problems with spatial learning and neuronal atrophy
• In more severe cases, Zn deficiency causes hair loss, delayed sexual maturation, impotence, hypogonadism in males, and eye and skin lesions, weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy
• The World Health Organization (WHO) advocates Zn supplementation for severe malnutrition and diarrhea, as Zn supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth
• Copper (Cu)


  A chemical element with symbol Cu and atomic number 29, in the top of group 11, of the periodic table, above silver and gold, with an atomic weight of 63.5, a reddish metal with a face-centered cubic crystalline structure, discovered in pre-historic times
• The human body only contains about 150 mg of Cu
• Recommended daily amount (RDA) for Cu

  2 mg/day for normal healthy adults
• Foods rich in Cu


  • Wheat, barley, sunflower seeds, almonds, pecans, walnuts, peanuts, cashews, prunes, raisins apricots, various dried beans, mushrooms, chicken, and most fish
• Cu


  • It is an essential constituent of several enzymes such as cytochrome oxidase, monoamine oxidase, catalase, peroxidase, ascorbic acid oxidase, lactase, tyrosinase, and superoxide dismutase (SOD)
  • It is involved in many metabolic reactions, for example, the presence of Cu in the SOD helps in the conversion of superoxide to oxygen and hydrogen peroxide
  • It is necessary for the hematologic and neurologic systems, the growth and formation of bone, formation of myelin sheaths in the nervous systems, helps in the incorporation of Fe in hemoglobin, assists in the absorption of Fe from the gastrointestinal tract, and in the transfer of Fe from tissues to the plasma
• Cu deficiency


  It is rare among healthy people, but it may occur among infants, the most common symptoms include fatigue, anemia, and a decreased number of white blood cells, and it may also cause osteoporosis, nerve damage, muscle weakness, confusion, irritability, and mild depression
• The most common cause of Cu deficiency is the remote gastrointestinal surgery, such as gastric bypass surgery, due to malabsorption of Cu
• Acquired Cu deficiency is mainly attributable to nutritional deficiency and may be seen in malnourished low-birth weight infants, newborns, and small infants, or after intractable diarrhea and prolonged parenteral or enteral nutrition
• Iron (Fe)


  A chemical element with symbol Fe and atomic number 26, the most abundant metal in the human body with a content of approximately 3-4 g, which almost corresponds to a concentration of 40-50 mg of Fe per kilogram of body weight
• Recommended daily amount (RDA) for Fe

  8 mg/day for men and post-menopausal women and 18 mg/day for menstruating women
• Foods rich in Fe

  • Red meat, liver, lentils, beans, peas, nuts, seeds, poultry, fish, seafood, leaf vegetables, watercress, tofu, chickpeas, black-eyed peas, blackstrap molasses, fortified bread, and fortified breakfast cereals
• Fe


  • The majority of Fe in the body is contained within hemoglobin, an erythrocyte protein that transfers oxygen from the lungs to the tissues
  • It is an essential component of myoglobin, a protein that provides oxygen to muscles
  • It is also involved in the transport of electrons within cells, the regulation of cell growth and differentiation, and the synthesis of some hormones
• RDA for Fe


  8 mg/day for men and post-menopausal women, 18 mg/day for menstruating women
• Rich sources of dietary Fe

  • Red meat
  • Liver
  • Lentils
  • Beans
  • Peas
  • Nuts
  • Seeds
  • Poultry
  • Fish
  • Seafood
  • Leaf vegetables
  • Watercress
  • Tofu
  • Chickpeas
  • Black-eyed peas
  • Blackstrap molasses
  • Fortified bread
  • Fortified breakfast cereals
  • Molasses
  • Teff
  • Farina
• Fe in meat is more easily absorbed than Fe in vegetables
• Hemoglobin


  Erythrocyte protein that transfers oxygen from the lungs to the tissues
• Myoglobin


  Protein that provides oxygen to muscles
• Fe is essential for growth, development, normal cellular functioning, and synthesis of some hormones and connective tissue
• Fe deficiency


  Condition where the body supply of available Fe is too low
• Fe deficiency is the most common nutritional deficiency in the world
• Symptoms of Fe-deficiency anemia

  • Tiredness
  • Weakness
  • Paleness in hands and eyelids
  • Fatigue
  • Dizziness
  • Hair loss
  • Twitches
  • Irritability
  • Brittle or grooved nails
  • Impaired immune function
  • Pagophagia
  • Restless legs syndrome
• Fe-deficiency anemia can be treated using Fe supplements
• Most vitamin/mineral supplements have Fe in them as common sulfates, fumarates, and gluconates