Zinc plays a vital role in fighting infection by preventing the immune system from spinning out of control, research has shown.
The finding may explain the common belief that taking zinc supplements at the start of a cold reduces symptoms.
It also has implications for intensive care treatment. But the scientists say it is too soon to recommend giving zinc to critically ill patients in intensive care units (ICUs).
The laboratory research showed how zinc stems excessive inflammation linked to sepsis, a devastating and potentially fatal reaction to infection.
Mice lacking zinc developed overwhelming inflammation in response to sepsis compared with mice on a normal diet.
When the deficient animals were given zinc supplements their condition improved.
Experiments with human blood cells showed that the calming effect of zinc was due to the way it binds to a specific protein in the inflammation pathway.
The findings are published in the journal Cell Reports.
Lead scientist Professor Daren Knoell, from Ohio State University in the US, said: "If you are deficient in zinc you are at a disadvantage because your defence system is amplified, and inappropriately so.
"The benefit to health is explicit: zinc is beneficial because it stops the action of a protein, ultimately preventing excess inflammation."
He added: "I think the question is whom to give zinc to, if anybody at all. We predict that not everybody in the ICU with sepsis needs zinc, but I anticipate that a proportion of them would.
"Zinc is a critical element that we get from our diet, but we do not think we can give zinc and fix everything. Usually, if there is zinc deficiency, we would expect to see other nutrient deficiencies, too."
Around two billion people worldwide are believed to be deficient in zinc.
Recommended daily allowances for zinc in the UK are 5.5 - 9.5 milligrams for men and four to seven milligrams for women. Taking too much zinc can lead to anaemia and bone weakening.
The Department of Health urges people not to take more than 25 milligrams of zinc a day unless advised to do so by a doctor.
Good sources of zinc include red meat, poultry, dairy products, shellfish, beans, nuts, and whole grains.
Here are 10 ways to boost your immune system and help keep the sniffles at bay.
There may be no more promoted solution to avoiding the flu this year (besides the flu shot, of course) than diligent hand washing. As many as 80 percent of infections are transmitted via contact like sneezing, coughing or touching surfaces that have been sneezed or coughed on, says Tierno, and then touching "your mouth, eyes or nose, which are the conduits of viruses into the body." He recommends scrubbing before eating, drinking or touching your face, and disinfecting shared surfaces in the home (like the bathroom) and the office, like phones, computers and fridge door handles.
While you're off in dreamland, your body gets to work repairing cells and injuries you may have incurred during the normal day's wear and tear, says Tierno. Getting your seven to nine hours a night means your body can repair and heal itself and ward off infections. "If you don't get the appropriate sleep, that system is not operating and you're on a steady decline over time," he says. In fact, skimping on sleep is <a href="http://www.huffingtonpost.com/2012/02/16/circadian-rhythms-immunity-immune-system_n_1281654.html">as disruptive to the immune system as stress</a>, according to a 2012 study. And earlier research suggested that sleep patterns may play a role in a gene that helps fight off bacteria and viruses.
Getting your blood pumping regularly can <a href="http://www.huffingtonpost.com/2012/01/07/exercise-immunity_n_1190296.html">increase the activity of a type of white blood cells</a> that attacks viruses. Shoot for an hour a day, says Tierno -- but not necessarily all at once. "Even if it's walking around the office, up stairs, down stairs, to and from work -- it doesn't have to be continuous," he says.
Getting the proper amount of the right nutrients and minerals as part of a healthy diet "leaves the body in optimal condition to fight the battle," says Tierno. This means cutting back on sugary, fatty foods and upping your intake of vegetables, fruit and lean protein, he says. One of those nutrients that gets a particularly healthy reputation during cold and flu season is zinc, and for good reason. "Zinc interferes with viruses gaining full access to our cells," he says. "Zinc may block certain metabolic activity." While it's <a href="http://www.huffingtonpost.com/2012/05/07/zinc-cold-symptoms_n_1497827.html">not the end-all cure</a>, foods rich in zinc, like <a href="http://www.huffingtonpost.com/lisa-turner/cold-prevention_b_2124507.html#slide=1771069">oysters</a> and <a href="http://www.huffingtonpost.com/2012/01/04/immune-boosting-superfood_n_1181192.html#s585162&title=Wheat_Germ">wheat germ</a>, may offer some protection.
The anti-microbial properties of this pungent bulb (and its relative, the onion) can fight off certain bacteria and viruses, says Tierno, as can the compounds in <a href="http://www.huffingtonpost.com/2012/11/08/healthy-herbs-spices-healthiest_n_2089007.html">other herbs and spices</a>, like thyme. It's likely due to the compound <a href="http://www.nytimes.com/2009/10/20/health/20real.html?_r=0">allicin, which seems to block infections</a>. Try it in your next bowl of soothing chicken soup!
Thankfully, most of us are inhabiting cozy-warm homes this winter, but those cranking radiators come with a downside. Indoor winter air is much dryer than our bodies would like. Without sufficient moisture, says Tierno, "immune system cells can't optimally work," so it's important to stay hydrated. (A <a href="http://articles.cnn.com/2009-02-11/health/healthmag.humidifier.flu_1_humidity-water-vapor-winter-flu-season?_s=PM:HEALTH">humidifier can also help</a>.)
Skipping Happy Hour
<a href="http://www.huffingtonpost.com/2012/12/28/alcohol-effects-body-infographic_n_2333328.html">Alcohol suppresses both the part of the immune system</a> that protects you from coming down with something and the part that fights off the germs already in your system, so knocking a few too many back can put you at increased risk for catching the bug going around -- and having trouble kicking it.
A positive attitude can take you far -- even, maybe, <a href="http://www.huffingtonpost.com/2012/07/06/personality-longevity_n_1652685.html#slide=1190731">to age 100</a>. But along the way, a life of laughter and optimism could also help you sniffle through fewer bouts of the flu or colds. While there's much that's still not well understood about the process, it seems that <a href="http://www.webmd.com/balance/features/give-your-body-boost-with-laughter">certain immune cells are produced</a> by a big belly laugh, says Tierno.
A <a href="http://www.huffingtonpost.com/2012/02/08/massage-benefits-health_n_1261178.html">favorite solution for de-stressing</a>, massage can also help you stay physically healthy. While there's been <a href="http://nccam.nih.gov/research/results/spotlight/090110.htm">little research into exactly how it works</a>, massage certainly increases circulation, which may help promote the general "state of wellness in the body," says Tierno. "Nutrients are passed around better, the blood flow is better," he says. "It's a very useful thing to get a massage."
A 1999 study found that getting frisky a couple of times a week can <a href="http://news.bbc.co.uk/2/hi/health/319070.stm">boost immunoglobin A</a>, an antibody that fights off colds. Just make sure your partner isn't already sick!
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