Common colds and upper respiratory tract infections (sore throats, coughs) are more common in the winter months, probably because we all spend so much more time together indoors. They are caused by viruses, tiny organisms typically spread by coughing or sneezing. Antibiotics only kill bacteria and so have no use in treating simple coughs and colds. Influenza (flu) is also a viral infection prevalent in winter but is potentially more serious. It often has prolonged more severe symptoms lasting 2-3 weeks and can lead to complications in some people, particularly for the very young, old or pregnant women. Fortunately there is vaccination available against flu each winter and in some cases anti-viral medication can be used for high risk people.
So what can be done to try to prevent these self-limiting but unpleasant viral illnesses and relieve their symptoms? Paracetamol is a safe and useful medication when used as directed to help pain and fever, rest and hydration are also very important. There are many other complimentary medicines that research has focused on in recent years to assess the usefulness in either prevention or reduction of symptoms of colds and flus. Vitamin C, Garlic, Honey, Echinacea spring to mind but how do we separate fact from old wives tale to see what really helps?
An excellent meta-analysis (summary of findings from many studies combined) was recently published by New York University (NYU). A brief outline of some of their most interesting findings along with other available research is outlined here.
What will help to prevent colds and flu?
Maintaining normal nutrient levels of zinc may work to prevent the frequency of colds as it plays an important role in normal immune system function. Once normal nutrient levels are present there is no benefit in taking extra zinc the very old and children are most at risk of dietary deficiency. Studies on supplementation in long term care facilities for the elderly and in children in the developing world where deficiency is more common have shown positive reduction in numbers of respiratory infections.Several studies have recognised a preventative role showing a reduction in the risk of getting a cold, school absence and antibiotic use in those using zinc supplementation compared with placebo.
There is good evidence to support the use of andrographis giving a statistically significant reduction in cold and flu symptoms as well as a possible increase in resistance to colds.
At doses of 400mg/day it was shown that ginseng may help to prevent common colds and influenza like illness in the elderly, reducing the number of colds experienced as well as the severity and duration of symptoms.
While it is unlikely to improve symptoms once a cold is established garlic has been shown in research to have a preventative role with the subjects in one study who took garlic regularly shown to have be two third less likely to catch a cold over a placebo group.
While there is strong evidence and much discussion over the use of probiotics in the prevention of intestinal infections there is also very good evidence to support a preventative effect against respiratory illness, in a trial studying children attending child care facilities. Similar affects have been found in the body of research into adult populations.
Especially preparations including Zinc and Selenium, may have a preventative role against respiratory infections in the elderly particularly in long term care. Vitamin D is a hot topic in research at present . There is some evidence to support a role in prevention of respiratory infections but it has not been proven to reduce cold symptoms or sick days from work. Glutamine in combination with Vitamin C may be useful in reducing post-exercise respiratory infection in athletes.
Symptom improvement: A cold has hit, how can you feel better, quicker?
Direct application of zinc in the form of gels or lozenges is thought to inhibit virus action once infection is present. However while there is some concern regarding the safety and efficacy of zinc in nasal gel form, zinc lozenges have been shown to be better than placebo in reducing cold and flu symptoms improving cough, sore throat and nasal drainage. (the preparation type is important, research supports in particular: zinc gluconate, zinc acetate). Starting zinc supplementation within 3 days of onset of symptoms has shown mixed results in research but there is some evidence to show there may be a reduction in symptoms of up to 2.6 days compared with placebo.
As yet research does not fully support its use in long term boosting of the immune system as a means to prevent colds but studies are ongoing. There is a strong body of evidence however demonstrating Echinacea s effectiveness in reducing the severity and duration of cold symptoms and an ability to abort a cold once it has already started. One small study did show that its use in combinations with Vitamin C and propolis had a role in prevention of viral respiratory illness in children but it is unclear what element of this combination may have been effective .
Research tends to show that Vitamin C, taken throughout the cold season at a dose of 1000mg or more daily (rather than once the cold occurs) may mildly reduce symptoms once an infection is present rather than reducing overall cold frequency. An exception to this seems to be in athletes where a benefit has been shown in reducing frequency of colds after endurance exercise such as marathons.
There is strong evidence to support the role of honey particularly in respiratory infections to reduce cough especially night time cough. It has been shown to be more effective than many over the counter cough medication for children or placebo ,in reducing nocturnal (night time) cough and improving sleep.
Bee propolis is showing some promise in this area but more new research is needed to fully define its role. Eucalyptus used in chest rubs and aromatherapy there is strong support for its beneficial use to improve sinus type symptoms, night time nasal congestion and cough.