Zinc has an important role in the activation of over one hundred enzymes. Zinc is important for:
- Antioxidant superoxide dismutase (along with copper) – protects membranes from oxidative damage.
- “Zinc finger proteins” bind to DNA affecting transcription and cell signaling.
- Helps regulate apoptosis important for cell growth, development and prevention of many chronic diseases.
- Normal neurological and behavioral development.
- Proper immune system to fight infections.
Hundreds of studies have been published on the benefits of adequate zinc with good scientific evidence that it:
- Reduces severity of diarrhea.
- Promotes the healing of stomach ulcers.
- Reverses known symptoms of zinc deficiency (growth and development problems, hair loss, diarrhea, impotence, eye and skin issues, poor appetite, poor wound healing, and mental slowness).
- Reduces or prevents acne.
- Improved ADHD, hyperactivity and impulsivity.
- Benefits those who are over weight or obese.
- Benefits the immune system, helps with herpes, the common cold and perhaps most infections.
- Helps block copper absorption for those with Wilson’s disease (excess copper).
Some evidence suggests zinc may be helpful for age related macular degeneration, as an appetite stimulant, to help with bad breath, helps boils, burns, and cancer sores (indeed many skin conditions), and helps with cancer prevention and chemotherapy side effects. Zinc seems to help anything involving brain function or lack of it, serious diseases like celiac, cystic fibrosis, Down’s syndrome, or any disorder affecting the immune system, including HIV, malaria, and parasitic infections. Diabetics have better blood sugar control with adequate zinc intake, and it can reduce nerve pain. Zinc supplementation has shown improved HDL to LDL ratios, improves thyroid function, helps inflammatory bowel disease and can improve kidney and liver function. Zinc seems to be important in reducing symptoms of inflammation, like rheumatic diseases, psoriasis, and vaginitis to name a few. Zinc may be effective for the treatment of warts.
SYMPTOMS OF DEFICIENCY
Although zinc deficiency wasn’t recognized until 1961, we now have lots of good information, much learned from the study of those born with acrodermatitis enteropathica (genetic impaired uptake and transport of zinc). Severe deficiency results in slowed growth and development, delayed sexual maturation and rashes, diarrhea, immune dysfunction and poor wound healing, poor appetite and loss of taste, night blindness, behavioral issues and clouding of the cornea along with vision problems. Other than those with the genetic disorder, zinc deficiency is most often seen in countries with limited food choices, those with severe and chronic diarrhea, bowel disorders and diseases, and severe burn victims.
Strict vegetarians with high intake of grains and legumes will have increased phytic acid that reduces zinc absorption resulting in a 50% greater need for zinc. Pregnancy is another very important time to be sure you get adequate zinc due to it’s importance in normal growth and development.
Oysters (3) 43-74
Beef (3 oz) 5-7
Crab (3 oz) 5
Chicken (dark 3 oz) 3
Pork (3 oz) 3
Beans and nuts (1oz) 1
Dairy (1 oz/cup) 1
Peas (1 cup) 1
Seeds/ wheat germ 1
Zinc fortified cereals
SAFETY AND TOXICITY
Immediate exposure (acute toxicity) occurs with exposures to over 225 mg of zinc. Symptoms are abdominal pain, nausea, diarrhea, and vomiting, fever, and muscle pain. This is usually from zinc bleached out of galvanized containers in which food or drinks were stored. If the exposure is from metal fumes this can result in sweating, weakness and rapid breathing that can last 12 – 24 hours. Mild gastrointestinal symptoms have been reported at zinc doses above 50-150 mg a day. Long term intakes above 150 mg a day can result in impaired immune function, decreased HDL, and impaired copper status leading to anemia, in addition to some of the above symptoms.
The FDA warned against the use of zinc in nasal sprays as it was leading to the loss of smell (anosmia).
UPPER TOLERABLE LIMITS
Children 1-3 7
Children 4-8 12
Children 9-13 23
Zinc supplements come as:
- zinc acetate (30% elemental).
- zinc gluconate (14% elemental).
- zinc picolinate (35% elemental).
- zinc sulfate (23% elemental).
100 mg of zinc acetate would thus be 30 mg of elemental zinc. RDA (recommended daily allowance) for zinc and upper limits are based on elemental zinc. RDA ranges from 2 mg a day for newborns to 13 mg a day for breast feeding moms.
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