Cure for common cold remains elusive
DEAR DOCTOR K: Is there any way to prevent a cold?
DEAR READER: The typical cold is a relatively mild misery that goes away without special treatment after about a week. Still, it's a misery most of us would rather avoid.
Colds are caused by viruses - more than 200 different types. Because the infection is not bacterial, antibiotics don't help. Over-the-counter cold medicines are available, but not always effective.
So the search continues for anything that can fend off cold-causing viruses or speed their exit from your body. Here is a rundown of some of the candidates.
- Vitamins. Nobel laureate Linus Pauling proposed that large daily doses - 1,000 to 2,000 milligrams (mg) - of vitamin C could prevent colds. Pauling was a genius who made major scientific discoveries and was awarded the Nobel Prize. But even geniuses can be wrong. By and large, research hasn't supported his assertion.
There's some evidence that vitamins D and E might help fend off respiratory infections, but the evidence is not strong enough to recommend either vitamin for cold-fighting purposes.
- Echinacea. The research hasn't been very encouraging. One review found some evidence that a certain part of one particular species of the Echinacea plant family might be an effective early treatment for colds in adults. Not exactly a ringing endorsement.
Other plant-based treatments, such as ginseng, elderberry, garlic and olive leaf, have been offered as cold preventives and cures. But none has emerged as clearly effective.
- Zinc. The results have been mixed. A 2011 meta-analysis found that generally healthy people who took zinc within 24 hours of the onset of cold symptoms reduced the duration and severity of their colds, compared to people who took a sugar pill. But there's no word yet on what dose and formulation of zinc is best.
- Exercise. Here's another reason to work out. Regular exercise may put your body in a better position to fight off a cold. Regular exercise seems to invigorate the immune system. (But there is also some evidence that the kind of intensive training that top athletes engage in can actually weaken the immune system.)
- Sleep. Your mother was right: Getting a good night's sleep keeps you healthy and may keep colds away. In one study, people who got less than seven hours of sleep a night were almost three times as likely to get a cold as those who got eight or more hours of sleep.
I know I'm going to get letters from people who swear that a vitamin, or an herbal preparation, or zinc works for them. I'm not really disagreeing with them.
Studies ask whether a particular treatment works for the average person. A treatment that does not work for the average person still may work for some people. Perhaps they have different genes. If you're convinced a treatment helps you, and if it doesn't pose any risk (and most of those above don't), then why not use it?
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.
tube and travel to the bladder. This tends to happen more often following sex, because sex tends to push the bacteria back up into the bladder.
There is a widely held belief that women and girls who wipe with toilet tissue from back to front following a bowel movement can also push bacteria up into the bladder. However, I once did a study that did not confirm this belief.
- Kidney infection. A kidney sometimes can become infected when bacteria cause a bladder infection. Long tubes called ureters connect the kidneys to the bladder; bacteria can sometimes make the long trip up the ureters to the kidneys. The symptoms of a kidney infection, in contrast to a bladder infection, include fevers, pain in the side of the back, nausea, shaking chills and sometimes low blood pressure. Kidney infections always need urgent medical attention.
- Urethritis is an inflammation of the urethra. It is usually caused by organisms that cause several sexually transmitted diseases, such as chlamydia. It also can be caused by contact with an irritating chemical (such as bubble bath or spermicides). Or it may result from irritation from an object, such as a tube inserted to drain urine.
- Vaginitis is an inflammation of the vagina. It can be caused by an allergic reaction to an irritating chemical such as a spermicide, douche or bath soap. Low levels of estrogen after menopause can cause vaginitis. So can an object such as a tampon. Infections including bacterial vaginosis, candidiasis and trichomoniasis scientific discoveries and was awarded the Nobel Prize. But even geniuses can be wrong. By and large, research hasn’t supported his assertion.
There’s some evidence that vitamins D and E might help fend off respiratory infections, but the evidence is not strong enough to recommend either vitamin for cold-fighting purposes.
- Echinacea. The research hasn’t been very encouraging. One review found some evidence that a certain part of one particular species of the Echinacea plant family might be an effective early treatment for colds in adults. Not exactly a ringing endorsement.
Other plant-based treatments, such as ginseng, elderberry, garlic and olive leaf, have been offered as cold preventives and cures. But none has emerged as clearly effective.
- Zinc. The results have been mixed. A 2011 meta-analysis found that generally healthy people who took zinc within 24 hours of the onset of cold symptoms reduced the duration and severity of their colds, compared to people who took a sugar pill. But there’s no word yet on what dose and formulation of zinc is best.
- Exercise. Here’s another reason to work out. Regular exercise may put your body in a better position to fight off a cold. Regular exercise seems to invigorate the immune system. (But there is also some evidence that the kind of intensive training that top athletes engage in can actually weaken the immune system.)
- Sleep. Your mother was right: Getting a good night’s sleep keeps you healthy and may keep colds away. In one study, people who got less than seven hours of sleep a night were almost three times as likely to get a cold as those who got eight or more hours of sleep.
I know I’m going to get letters from people who swear that a vitamin, or an herbal preparation, or zinc works for them. I’m not really disagreeing with them.
Studies ask whether a particular treatment works for the average person. A treatment that does not work for the average person still may work for some people. Perhaps they have different genes. If you’re convinced a treatment helps you, and if it doesn’t pose any risk (and most of those above don’t), then why not use it?
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.