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NUTR 439: Communications in DieteticsMay 18th, 2009
Sarah Hallaj
Can Zinc Supplements Reduce the Duration of
Colds?
I. IntroductionBackground information on zinc Different forms of zinc supplements
II. BodyHow zinc supplements work with virusesA.Research study that support the controversial
issueB.Research study that refute the controversial
issueC.Comparison of studies
III. Conclusion Do zinc supplements really work?
Outline:
Zinc is an essential micronutrient mineral that has many functions in the human body. It provides both a structural, catalytic, and regulatory control on the cellular level in our bodies.
Zinc plays a vital role in:• Neurological function• Growth and development• Immune function
•The zinc RDA for adults is 11mg/day for males and 8mg/day for females.
•Good food sources of zinc are found in meat products (oysters and beef) and in legumes and nuts.
•Zinc in oysters and beef is more bioavailable than in legumes and nuts due to the presence of cysteine and methionine amino acids which increase absorption1.
http://george-eby-research.com/gif/zinc-sources.jpg
So, what about zinc supplements?
The many different types of zinc supplements have been suggested to decrease the duration of colds; but still remains a controversial issue.
Some research studies support it while others claim that its disadvantages outweigh its benefits.
Zinc is found in many supplement forms such as: gels, lozenges, and sprays.
Different zinc compounds include: zinc sulfate, zinc acetate, and zinc gluconate.
Each of these compound forms differ in the amount of zinc provided and in absorption.
Some forms are more soluble than others2.
http://www.purac.com/ufc/rapid2/274bba2acc1ca24f21a0fbba973cc2af/purac_sites/objects/c1d1472fd832f9b4e1d9c9c1ed42c2df/page_bestanden/image001.gif
Increase oxidative stress
Activate macrophage and monocytes
Increase production of inflammatory molecules 3
Common Cold Viruses:
Prasad. A. 2008.
How do zinc supplements work?
• Zinc inhibits rhinovirus particles from
attaching to ICAM-1 (Inter-Cellular Adhesion Molecule 1) on the nasal epithelium
• ICAM-1 is an anti-inflammatory molecule
• Zinc prevent rhinovirus from replicating4
Hulisz, D. 2004.
A review article hypothesized
Randomized double-blind, placebo-controlled trial of zinc
Fifty healthy volunteers were recruited free of any illness
Participants took 1 lozenge of zinc acetate containing 13.3 mg zinc upon developing symptoms of cold
Placebo and zinc tablets were identical in shape, color, and sweetness in taste 3
Summary of a study
Prasad. A. 2008.
Mean duration of cold was 4.0 days in the zinc group and 7.1 days in the placebo group
The duration of cough, nasal discharge, and mucous were significantly shorter in the zinc group
Zinc group has decreased plasma levels of inflammatory molecules (ICAM-1)
Results:
Taken within 24hours of the onset of a cold
Taken every 2-3 hours while awake for 3-5 days
Taken in the form of zinc lozenges
Zinc supplments work if:
Double-blind placebo-controlled clinical trialSeventy seven participants had two or more
symptoms of the common coldParticipants received 10 mmol zinc gluconate
nasal spray every 15-30 minutesZinc orotate lozenges containing 37mg zinc
were supplemented and taken every 2-3 hours while awake
Placebo was free of zinc but otherwise identical 5
Summary of another study:
Eby G. 2006.
No evidence of reduction of cold duration in both groups
Zinc group reported more adverse effects than placebo group
Some side effects included: mouth irritation, mouth sores, diarrhea, nasal pain and discomfort
Results:
Researchers explained that even though zinc orotate lozenges has high zinc concentrations, but it is slightly soluble in water and is non-ionizable under physiologic conditions
This explains why zinc lozenges did not have positive effects on cold duration
Zinc nasal sprays caused nasal pain and irritation
Researchers claimed that 10 mmol of zinc gluconate was the upper tolerable concentration that causes long lasting intra-nasal pain and anosmia
Anosmia is inability to perceive smell!!
Researchers explained that zinc, a heavy metal, passes via olfactory receptor neuron to the olfactory bulb, and reaching the nuclei of the brain
Ionic zinc physically destroys olfactory epithelium and causes atrophy of the olfactory bulb producing anosmia
Comparing the studiesThe studies were not all using the same controls,
which might explain the differences in results.
Different zinc supplement forms and compoundsDifferent zinc amountsDifferent duration of studies
Participating subjects were not of the same age groups (children and adults) and differences in ethnic backgrounds were not considered.
A common control point was that all subjects were asked to not take any other cold remedy while being observed for the study; with the exception of one study where the children received other drugs if they had a fever5.
All articles reviewed looked at the class of rhinoviruses that cause the most common type of cold.
One must keep in mind that it is hard to monitor subjects when they are at home.
Conclusion:
It is best to avoid using zinc nasal sprays due to irreversible anosmia-causing effects.
Short-term use of zinc lozenges shortens the duration of colds and does not resulted in serious side effects.
It is safe to use zinc lozenges within 24 hours on the onset of a cold every 2-3 hours while awake for 3-5 days .
If symptoms persist then one should refer to a physician.
[1] Higdon, J. Zinc. Linus Pauling Institute Micronutrient Research for Optimum Health. 2008. Available at: http://lpi.oregonstate.edu/infocenter/minerals/zinc/index.html#rda. Accessed April 11, 2009.
[2] Gropper S, Smith J, Groff J. Advanced Nutrition And Human Metabolism. Belmont, CA: Wadsworth; 2005 [3] Prasad A, Beck F, Bao B, Snell D, Fitzgerald J. Duration and Severity of Symptoms and Levels of Plasma
Interleukin-1 Receptor Antagonist, Soluble Tumor Necrosis Factor Receptor, and Adhesion Molecules in Patients with Common Cold Treated with Zinc Acetate. J Infec Disease. [18279051]. 2008; 197: 795-802. Available at: http://proxy.library.oregonstate.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=cmedm&AN=18279051&loginpage=Login.asp&site=ehost-live. Accessed April 11, 2009.
[4] Hulisz, D. Efficacy of Zinc Against Common Cold Viruses: An Overview. JAPhA[5]. 2004; 44: 594-603. Available at: http://mw8xt6bj7r.search.serialssolutions.com/?genre=article&issn=15443191&title=Journal+Of+The+American+Pharmacists+Association%3a+Japha&volume=44&issue=5&date=20040901&atitle=Efficacy+of+zinc+against+common+cold+viruses%3a+an+overview.&spage=594&pages=&sid=EBSCO:MEDLINE&aulast=Hulisz+D . Accessed April 13, 2009.
[5] Eby G, Halcomb W. Ineffectiveness of Zinc Gluconate Nasal Spray and Zinc Orotate Lozenges in Common-cold
Treatment: A Double-Blind, Placebo-controlled Clinical Trial. Alternative Therapies. Jan/Feb 2006; 12: 34-37. Available at: http://web.ebscohost.com/ehost/detail?vid=4&hid=115&sid=718a55e6-1b33-41d9-95b0-bb2d6f136b39%40SRCSM2&bdata=JmxvZ2lucGFnZT1Mb2dpbi5hc3Amc2l0ZT1laG9zdC1saXZl#db=cmedm&AN=16454145. Accessed April 8, 2009.
[6] Kurugol Z, Akilli M, Bayram N, Koturoglu G. The Prophylactic and therapeutic effectiveness of zinc sulphate on common cold in children. Acta Paediatrica. 2006; 95: 1175-1181. Available at: http://web.ebscohost.com/ehost/detail?vid=9&hid=2&sid=718a55e6-1b33-41d9-95b0-bb2d6f136b39%40SRCSM2&bdata=JmxvZ2lucGFnZT1Mb2dpbi5hc3Amc2l0ZT1laG9zdC1saXZl#db=cmedm&AN=16982486. Accessed April 8, 2009.
References:
The End!