Zinc Supplements

See Also: Zinc Deficiency, and Zinc Excess and Zinc Toxicity.

• Zinc supplements (zinc sulphate) should be given only when there is good evidence of deficiency or in zinc-losing conditions.¹
• Zinc sulphate is used to treat Wilsons disease.
  Studies have also reported its use to enhance wound healing and slow macular degeneration.
• Zinc has also been claimed to ameliorate a variety of conditions including the common cold. The effect of zinc treatments on the severity or duration of cold symptoms is controversial and unproven.²
• A zinc supplement is given until clinical improvement occurs but it may need to be continued in severe malabsorption, metabolic disease or in zinc-losing states.
• Total parenteral nutrition regimens usually include trace amounts of zinc. If necessary, further zinc can be added to intravenous feeding regimens.

• May accumulate in acute renal failure.
• A small study has suggested that zinc supplementation increases the levels of glycosylated haemoglobin in diabetics.
• Sufferers from haemochromatosis may absorb larger amounts of zinc.

• Zinc and copper are mutually antagonistic, each interfering with the gastrointestinal uptake of the other. Zinc and iron also compete for absorption.
• Excess zinc may also decrease magnesium and calcium uptake. High levels of calcium in the diet can decrease zinc absorption.
• Zinc salts reduce the bioavailability of fluoroquinoline antibiotics, e.g. ciprofloxacin.
• Absorption of zinc is reduced by penicillamine and zinc also reduces the absorption of penicillamine
• Absorption of zinc is reduced by tetracyclines and zinc also reduces the absorption of tetracyclines

• Zinc supplements have been reported to cause gastrointestinal effects, including abdominal pain, dyspepsia, nausea, vomiting, diarrhoea, gastric irritation, gastritis. This is more likely when supplements are taken with little or no food.
• Irritability, headache, lethargy, dizziness
• Prolonged use of high doses of zinc can result in deficiency of copper.
• It has been suggested but not proven that excess zinc is atherogenic.²