Zinc ions and the fight against SARS
The discovery that SARS is caused by a coronavirus, related to a
group of viruses causing the common cold, may be of considerable
significance in relation to evidence that zinc ions provide a natural
protective mechanism against viruses - especially those causing
respiratory tract infections. Over the past 30 years, researchers have
demonstrated the critical role of zinc in diverse physiological processes,
such as growth and development, maintenance and priming of the immune
system, and tissue repair.
Direct antiviral effects of zinc ions have been demonstrated against
rhinoviruses responsible for the common cold (1,2,3,4,5) and the role of
zinc in the respiratory epithelium has recently come under scrutiny(6).
Zinc has also been shown to directly decrease the incidence of respiratory
infections in young children from developing countries (7) probably by
mechanisms that involve restoration of T-cell immunity lost as a result of
deficiency of this mineral.
Zinc deficiency has been described as worldwide public health problem
and it is not confined to developing countries. Even in the USA moderate
to severe zinc deficiency can occur throughout the population. The causes
of zinc deficiency are multiple. They include:-
Food grown in soils that are low in zinc,
Superphosphate fertilizers that reduce zinc uptake by plants.
Eating foods that are low in zinc. (Very few foods are
Poor absorption of zinc from the stomach and intestines.
Food contaminants and additives further reducing intestinal
Excessive zinc loss through body fluids such as sweat and
Poor body storage of zinc.
Strategies to overcome zinc deficiency are now being considered in
many developing countries and these include zinc supplementation and food
fortification. But now here is a problem! Zinc tablets and fortified
foods both aim to deliver the zinc through gastrointestinal absorption,
which can be very inefficient. Plant phytates and the presence of other
essential minerals such as iron and calcium can all reduce zinc uptake
from the gut. A better route for zinc absorption is the mouth and throat.
The development of zinc lozenges that release zinc ions in the buccal
cavity can have great benefits for both local actions to combat
respiratory tract viruses and to facilitate general zinc repletion.
Although zinc lozenges are available, most products fail to achieve
their goals because the amount of zinc they contain is too low or because
the formulation contains substances such as Vitamin C that trap the zinc
ions. The reason that these unsatisfactory lozenges exist is one of taste
as the ability to produce a pleasant-tasting zinc lozenge with sufficient
dose has eluded most manufacturers. By contrast, our research in South
Africa and the UK has focussed specifically on development of maximum
strength 15mg zinc lozenges (Zinc Advance) that have an excellent and
taste profile. Even young children enjoy sucking them.
Zinc ions when released in the vicinity of the oral mucous membranes
can protect cells from attack by viruses such as rhinoviruses. It is
believed that zinc ions attach to cell surface receptors thereby blocking
viral attachment and uncoating (8) Whilst there is not yet any evidence
that attachment of the coronavirus causing SARS can be blocked by zinc
ions, they are thought to help repair microscopic holes punched in cell
membranes by viruses(9) .
I believe there could be considerable benefit from the widespread use
of maximum strength zinc lozenges as a precautionary measure during the
SARS pandemic. Moreover, the extensive use of such lozenges would raise
the general level of immune status in the community with several important
1. An increase the general resistance to viral infections.
2. Possible reduction in the mortality rate from infections such as SARS
3. Reduction in the number of other viral infections that cause fevers
thereby reducing the burden on an over-stretched health-care profession.
Perhaps the work, which has led to the availability of effective zinc
lozenges since 2000 in the UK, could be of benefit
at this time.
G.F.Rowland BSc, PhD
ZinCare International Ltd
For further information please contact:
Zeon Healthcare Limited,
PO Box 32,
Cheltenham GL54 2WD
1. Geist F. C., Bateman J. A., Hayden F. G. In vitro activity of zinc
salts against human rhinoviruses. Antimicrob. Agents Chemother.
2. Korant B. D., Butterworth B. E. Inhibition by zinc of rhinovirus
protein cleavage: interaction of zinc with capsid polypeptides. J. Virol.
3. Al-Nakib W., Higgins P. G., Barrow I., Batstone G., Tyrrell D. A.
Prophylaxis and treatment of rhinovirus colds with zinc gluconate
lozenges. J. Antimicrob. Chemother. 1987;20:893-901
4. Mossad S. B., Macknin M. L., Medendorp S. V., Mason P. Zinc
gluconate lozenges for treating the common cold: a randomized, double-
blind, placebo-controlled study. Ann. Intern. Med. 1996;125:81-88
5. Prasad AS, Fitzgerald JT, Bao B, Beck FW&Chandrasekar
PH.Duration of symptoms and plasma cytokine levels in patients with the
common cold treated with zinc acetate. A randomized, double-blind, placebo
-controlled trial.Ann. Intern. Med. 2000; 133: 245-52
6. Truong-Tran Ai Q, Joanne Carter, Richard Ruffin and Peter D
Zalewski New insights into the role of zinc in the respiratory epithelium.
Immunology and Cell Biology 2001; 79:170 - 178.
7. Sazawal S, Black RE, Jalla S, Mazumdar S, Sinha A&Bhan MK.
Zinc supplementation reduces the incidence of acute lower respiratory
infections in infants and preschool children: a double-blind, controlled
trial.Pediatrics 1998; 102: 1-5.
8. Novick SG, Godfrey JC, Pollack RL&Wilder HR.Zinc-induced
suppression of inflammation in the respiratory tract, caused by infection
with human rhinovirus and other irritants.Med. Hypotheses 1997; 49: 347-
9. Pasternak C. A. A novel form of host defense: membrane protection
by Ca2+ and Zn2+. Biosci. Rep. 1987;7:81-91
The author is a founder and share-holder of ZinCare International Ltd
Competing interests: No competing interests