Giving zinc a think

Communicable Diseases 118 views

There is evidence that zinc supplements are effective in reducing cold symptoms after onset, but some caution in taking it is advised.

Giving zinc a think

As the common cold grows less common, increasingly hard to distinguish from flu, people look for better cold remedies. You may have noticed that an increasing number of over-the-counter cold remedies emphasize that they contain zinc. It turns out there’s a reason, but as usual there are some cautions as well.

Look, if we had the cure for the common cold, we’d be writing to you from some tropical island, probably one we owned—or more likely not writing at all. So many rays, so little time.

But we’ve looked into it, and what we have learned is that there’s something approaching a consensus that a zinc supplement—particularly if taken within 24 hours of the onset of cold symptoms—can reduce the length of a cold by as much as 40%. Of course it’s hard to measure something that’s no longer there, so best you approach the matter reasonably.

So does it or doesn’t it?

Yes. There’s both clinical and anecdotal evidence that zinc supplements may reduce symptoms of the common cold such as congestion. That’s the symptom most cold sufferers seek relief from. Where there is no confirming data as yet is that it is as effective as a cold preventative.

Zinc does appear to be an immune-system booster, and it has been used to treat a range of medical problems from acne to Alzheimer’s. Its specific benefits seem to vary by the user, yet used in reasonable amounts, it appears to have no deleterious effects. As usual, dosage is all.

So what’s the right dosage?

The only reasonable answer is: the one your doctor recommends. In the literature written for lay people, you’ll find answers from 8 to 150 milligrams per day of “free zinc” up to 220 milligrams as a chelated zinc, usually zinc sulfate. A chelated substance is one that is combined with another substance to promote its absorption into the system. Indications are that zinc alone does not absorb well, but the good news there is that it’s difficult to find in its “free” state.

The reason to check with your doctor is that it is possible to overdose on zinc, as it is with any metal. A zinc overdose may not be disastrous, but it can prevent the absorption of other metals your body needs to be healthy, particularly including iron and copper. It also can lead to diarrhea and dehydration.

To be plain about it, the risk is that precisely because it is easily available over the counter, some people conclude that that means it’s not very strong and can be taken at a higher than recommended dose without consequences. Again, the truth seems to be that it is possible to increase zinc uptake during a cold, as long as the increase it not too great and does not go longer than a few days.

It’s a metal?

Zinc is a naturally occurring trace metal that sits on a very comfortable perch on the third row of the Periodic Table of the Elements. The human body needs these metals, but in the right concentrations and through appropriate means of delivery.

It occurs naturally in the environment and is found in easily available foods.

It is found in its highest concentration in oysters, but is also present in most red meats, dense-textured seafood such as crab and lobster, as well as in some beans, nuts and grains. Many commercially available breakfast cereals are now “fortified” with zinc. Vegetarian diets tend to be relatively low in zinc, which may make zinc supplements advisable for adherents to the stricter forms of vegetarianism.

So what about taking it for colds?

According to the Mayo Clinic, zinc supplements may prevent cold viruses from multiplying and invading the nose and throat. For that reason, it was available as a nasal inhalant but is now strongly contraindicated in that form. But the U.S. Food and Drug Administration has taken zinc nasal sprays off the market, as they have been known to cause loss of smell for very long periods of time. It is still available as a throat spray, but the caution there is that throat sprays can easily enter the nose.

It works best taken in lozenge form, and the recommendation is that the lozenge be dissolved in the mouth, ideally under the tongue, rather than chewed. The slower the absorption, the more is absorbed.

Because medical authorities disagree about the maximum beneficial dose for adults, check with your doctor or pharmacist before you take zinc supplements, and do not assume that you can “pop” them for speedier cold relief. Zinc plays an important role in child development, but dosing a child with a cold is a particularly delicate matter. By all means consult your child’s doctor first.

Should I take it regularly?

The correct answer is that you should get enough zinc. Its benefits in immune enhancement and processes like wound healing are known. But you may get sufficient zinc in a healthy diet, and you may need to supplement it only during episodes like colds, and then only for a few days at a time. These are matters to be worked out over the long term, and you may find the readings listed below helpful.


For further reading:,,20929453,00.html#zinc-rich-foods-,,20929453,00.html


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