Zinc has come to the limelight during the current COVID-19 pandemic as a possible adjunct remedy. Some Healthcare providers have reported (or postulated) that Zinc prevents the COVID-19 virus from replicating (reproducing). A detailed fact sheet on Zinc supplements can be found at the National Institutes of Health Office of Dietary Supplements under the US Department of Health & Human Service
Although the British National Formulary (BNF) states that, ‘Zinc supplements should not be given unless there is good evidence of deficiency’, most multivitamin/mineral supplements available in the US contain some amount of Zinc which should be sufficient for any required daily need.
Zinc is one of the trace elements needed for normal human function and is usually obtained adequately from a normal healthy diet. Knowing that some people may want to go out and buy zinc and start taking unnecessary large doses of Zinc to prevent falling sick from the COVID-19 virus, it is important to educate the public on possible side effects and drug interactions with Zinc supplements.
Side effects (from BNF #66)
Zinc side effects include
Avoid high doses of Zinc as this makes the side effects worse.
Caution (from BNF #66)
Zinc supplements should be taken with caution in patients with
renal failure (zinc accumulation),
pregnancy (Zinc crosses the placenta) and
breast-feeding mothers (found in breast-milk).
Interactions (From National Institutes of Health Office of Dietary Supplements)
Large amounts of supplemental iron (greater than 25 mg) might decrease zinc absorption. Taking iron supplements between meals helps decrease its effect on zinc absorption.
High zinc intakes can inhibit copper absorption, sometimes producing copper deficiency and associated anemia
Both quinolone antibiotics and tetracycline antibiotics interact with zinc in the gastrointestinal tract, inhibiting the absorption of both zinc and the antibiotic. Taking the antibiotic at least 2 hours before or 4–6 hours after taking a zinc supplement minimizes this interaction.
Zinc can reduce the absorption and action of penicillamine. To minimize this interaction, individuals should take zinc supplements at least 2 hours before or after taking penicillamine.
Thiazide diuretics such as chlorthalidone and hydrochlorothiazide increase urinary zinc excretion by as much as 60%. Prolonged use of thiazide diuretics could deplete zinc tissue levels, so clinicians should monitor zinc status in patients taking these medications.
Dietary sources of Zinc (From National Institutes of Health Office of Dietary Supplements
In conclusion, I would like to mention some dietary sources of Zinc which include whole grains, milk products, oysters, red meat, poultry, baked beans, chickpeas, and nuts (such as cashews and almonds).
Thanks for reading and stay safe.