Zinc (Zn++)

Functions

  • over 200 enzymes require zinc as a catalyst
  • required to produce enzymes necessary for
    • digestion
    • cell division, growth, and repair (healing)
  • helps immune system function properly
  • plays role in acuity of taste and smell
  • plays role in night vision
    • mobilization of vitamin A from liver
      • converts to retinol and then to retinoic acid
  • sexual maturation

Deficiency

  • wounds slow to heal
  • thin or peeling nails
  • acne
  • hair loss
  • impaired night vision
  • elevated cholesterol
  • loss of smell and taste/appetite
  • susceptibility to infection
  • impotence
  • stunted growth and delayed sexual development in children

Characteristic

  • Trace Mineral

Good Sources

Zinc

Natural

  • beef, chicken
  • liver
  • seafood
    • fish, shellfish
  • milk and dairy products
  • eggs
  • whole grains
  • legumes, peas
  • nuts
  • pumpkin and sunflower seeds
Food Quantity mg
Yogurt, low-fat 8 oz 1.5
Lentils, boiled 1 cup 2.5
Turkey, dark meat, roasted 3.5 oz 4.4
Peanuts 1 oz 0.9
Beef, ground round steak 3.5 oz 5,6

Artificial

  • wheat germ
  • fortified cereals

Recommended Daily Allowances (RDA)

  • Males (11 yrs. and older)
    • 11 mg
    • 15 mg
  • Females (11 yrs. and older)
    • 8 mg
    • 12 mg
  • Pregnant females
    • 30 mg
  • Lactating females
    • 15 mg
  • Children
    • 10 mg
  • Infants
    • 5 mg
  • Varied values reflect different references

Tolerable Upper Intake Levels (UL)

  • Adults (19 to 50 yrs)
    • 40 mg
  • Intakes above UL may lead to negative health consequences.
    • Nausea, vomiting, abdominal pain
    • impaired coordination
    • fatigue

Supplementation

  • Not generally recommended
    • except by a doctor for few people who have low zinc levels.
  • Others recommend 22.5-50 mg daily
  • Best taken with calcium, cooper, phosphorus, vitamin B-6
  • Zinc compounds are used as an active ingredient in nasal spray and throat lozenges to decrease the duration and severity of the common cold.
  • Excessive zinc (50 mg / day or more) interferes with copper absorption
    • Zinc lozenges for prolonged periods (>6-8 weeks) is likely to result in copper deficiency.
  • High dosages of Iron supplements (38-65 mg/day) but not dietary levels of iron may decrease zinc absorption​​​​​​​
    • When taken with food, supplemental iron does not appear to inhibit zinc absorption.
    • Iron-fortified foods have no effect on zinc absorption

Notes

  • Zinc is primarily (95%) found in muscle, bone, skin, and hair.
  • Only 5% is labile and accessible in liver and plasma.
  • Plasma zinc is 99% bound
    • albumin (80%), a-2 macroglobulin (15%), and other low-molecular-weight proteins.
  • Metallothioneins (type of intracellular monomeric polypeptides)
    • bind zinc and act as homeostatic modulators of zinc availability
  • Serum concentrations of zinc decrease sharply in inflammation.

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