Zinc

Zinc is a nutrient that is included in many essential processes in the human body. Over 100 enzymes can’t work without it, it’s included in DNA replication and cell division, wound healing and protein synthesis. Zinc affects multiple aspects of the immune system and also functions as an antioxidant and can stabilize membranes.Zinc is also needed for the senses of smell and taste. During pregnancy, infancy, and childhood the body needs zinc to grow and develop properly. Zinc also enhances the action of insulin.

In other words zinc is an important trace mineral that people need to stay healthy. Of the trace minerals, this element is second only to iron in its concentration in the body.

What happens if I don’t get enough zinc?

Zinc deficiency is rare in North America. It causes slow growth in infants and children, delayed sexual development in adolescents and impotence in men. Symptoms of zinc deficiency include:

  • Frequent infections
  • Hypogonadism in males
  • Loss of hair
  • Poor appetite
  • Problems with the sense of taste
  • Problems with the sense of smell
  • Skin sores
  • Slow growth
  • Trouble seeing in the dark
  • Wounds that take a long time to heal

Many of these symptoms can be signs of problems other than zinc deficiency. If you have these symptoms, your doctor can help determine whether you might have a zinc deficiency.

Food sources

Animal proteins are a good source of zinc. Beef, pork, and lamb contain more zinc than fish. The dark meat of a chicken has more zinc than the light meat.

Other good sources of zinc are nuts, whole grains, legumes, and yeast.

Fruits and vegetables are not good sources, because the zinc in plant proteins is not as available for use by the body as the zinc from animal proteins. Therefore, low-protein diets and vegetarian diets tend to be low in zinc.

Zinc is in most multivitamin and mineral supplements. These supplements may contain zinc gluconate, zinc sulfate, or zinc acetate. It is not clear whether one form is better than the others.

Zinc is also found in some over-the-counter medicines, such as cold lozenges, nasal sprays, and nasal gels.

Can zinc be harmful?

Yes, if you get too much. Signs of too much zinc include nausea, vomiting, loss of appetite, stomach cramps, diarrhea, and headaches. When people take too much zinc for a long time, they sometimes have problems such as low copper or iron levels, lower immunity, and low levels of HDL cholesterol (the “good” cholesterol).

The upper limits for zinc are listed below. These levels do not apply to people who are taking zinc for medical reasons under the care of a doctor:

Life Stage Upper Limit
Birth to 6 months 4 mg
Infants 7-12 months 5 mg
Children 1-3 years 7 mg
Children 4-8 years 12 mg
Children 9-13 years 23 mg
Teens 14-18 years 34 mg
Adults 40 mg

Precautions when taking zinc supplement

Zinc dietary supplements can interact or interfere with medicines that you take and, in some cases, medicines can lower zinc levels in the body. Here are several examples:

  • Taking a zinc dietary supplement along with quinolone or tetracycline antibiotics reduces the amount of both zinc and the antibiotic that the body absorbs. Taking the antibiotic at least 2 hours before or 4-6 hours after taking a zinc dietary supplement helps minimize this effect.
  • Zinc dietary supplements can reduce the amount of penicillamine (a drug used to treat rheumatoid arthritis) that the body absorbs. They also make penicillamine work less well. Taking zinc dietary supplements at least 2 hours before or after taking penicillamine helps minimize this effect.
  • Thiazide diuretics increase the amount of zinc lost in the urine. Taking thiazide diuretics for a long time could decrease the amount of zinc in the body.

 

Tell your doctor, pharmacist, and other health care providers about any dietary supplements and medicines you take. They can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines or if the medicines might interfere with how your body absorbs, uses, or breaks down nutrients.

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