Does zinc help us when colds come calling? While it isn't proven to prevent colds, there is evidence showing that it can shorten the duration of cold symptoms. Just be aware of dosage and potential side effects.

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You’re achy and stuffy and your throat feels like you swallowed sandpaper. Congratulations! You’ve got a cold. Now what? From eating chicken soup to sleeping in wet socks, people try a multitude of cures for the common cold. One of the best scientifically proven remedies, however, can be found in your fridge—zinc.

A mineral, zinc is found naturally in protein sources such as poultry, red meat, and fish. Trace amounts of zinc are essential for our optimal health. Since our bodies don’t store it, we must be vigilant about consuming zinc in our diet. If we don’t get enough zinc, we could suffer from illnesses such as stunted growth, acute diarrhea (mainly in children), slow wound healing, dysfunction of the testes and ovaries, a reduced ability to taste food, and Wilson’s disease.

Can Zinc Really Fight Off a Cold?

If you research this question, you’ll find mixed results. While science so far indicates that zinc won’t prevent a cold, there’s mounting evidence that it shortens the duration of a cold. A study published in Open Forum Infectious Diseases found that patients who took zinc lozenges recovered three times faster than those who didn’t take the supplement. On the fifth day of the trial, 70 percent of the zinc-taking patients had recovered from their colds while 27 percent of those who took placebos had not.

As long as you don’t suffer from an underlying illness (e.g., an immunodeficiency, asthma, or a chronic disease), taking zinc within 24 hours of noticing cold symptoms should cut the time spent suffering, says Melanie Boehmer, MS, RD, CDN, CISSN at Lenox Hill Outpatient Nutrition in New York City.

Those who have chronic conditions may also be helped by zinc, but as of now, there’s no research to prove that’s true.

How Does Zinc Shorten a Cold’s Duration?

“Most colds,” Boehmer explains, “are caused by a type of virus called rhinovirus, which thrives and multiplies in the upper respiratory system. Zinc may work by preventing the rhinovirus from multiplying. It may also stop the rhinovirus from lodging in the mucous membranes of the nose and throat.”

How Much Zinc Should You Take?

A Finnish study of 575 cold-ridden people found those who were given 80 to 92 mg of zinc daily noticed a 33 percent reduction in cold symptoms. Those who received more (between 192 and 207 mg/day) noticed a 35 percent reduction, which was a minimally better effect. Their conclusion: “There is no evidence that zinc doses over 100 mg/day might lead to greater efficacy in the treatment of the common cold.”

Your take-home? Aim for 80 to 92 mg a day when you’re fighting a cold. For best results, start boosting your zinc intake (or consuming lozenges as per the packaging label) as soon as you notice symptoms.

Zinc’s Benefits

Zinc’s main attribute is its ability to boost the immune system. It is also essential in helping our blood to clot, wounds to heal, and thyroid to function, among other benefits. In addition to finding it in foods, you can take zinc as a lozenge, eye drop, injection, pill, nose spray, mouth wash, chewing gum, candy, toothpaste, or topical cream to:

• Combat the swine flu
• Heal an ear infection
• Help lessen tinnitus (a.k.a. ringing in the ear)
• Improve growth
• Prevent and treat a lower respiratory infection
• Prevent cavities
• Treat a bladder infection
• Treat macular degeneration
• Treat malaria
• Treat night blindness

Other conditions that are treated with zinc include:

• Acne
• Alzheimer’s disease
• Attention deficit-hyperactivity disorder (ADHD)
• Cancer
• Chronic obstructive pulmonary disease (COPD)
• Dementia
• Down syndrome
• Canker sores
• Crohn’s disease
• Cystic fibrosis
• Eczema
• Dry mouth
• Inflammatory bowel disease
• Leg ulcers
• Liver disease
• Osteoporosis
• Ovarian cysts
• Postpartum depression
• Psoriasis
• Rheumatoid arthritis
• Rosacea
• Sickle cell disease
• Stomach ulcers
• Warts

Zinc’s Side Effects

Research has yet to discover serious side effects associated with zinc, but there nonetheless are side effects to consider. Boehmer warns that zinc lozenges could cause the following: a foul taste in the mouth, nausea, vomiting, stomach cramps, and diarrhea.

Taking too much zinc also can cause more serious problems, especially if taken over a long period of time. High levels of zinc have been shown “to interfere with the absorption of certain antibiotics and other minerals, like iron and copper,” Boehmer says. “These interactions may be minimized by recommending zinc with food and taken separate from medications.”

Other rare side-effects that could require a doctor visit may include:

• Chills
• Fatigue
• Fever
• Heartburn
• Indigestion
• Nausea
• Sore throat
• Ulcers in the mouth or throat