Common Cold


Common Cold


It’s that time of year when every other person seems to be blighted by a cough, a runny nose or a sore throat. Collectively, these ailments are usually referred to as ‘upper respiratory tract infections’ and are caused by a variety of viruses including the rhinovirus.


The cure for the common cold has deceived medical science since the birth of modern medicine and affects the average Brit between 2 and 4 times each year for an adult and up to 8 times a year for an infant. Vaccinations against these viruses have so far not been possible due the vast numbers of different viruses which cause similar symptoms. For this same reason, your immune system struggles to develop resistance to these viruses, because as soon as it’s developed antibodies against one strain, another comes along and breaches your defences. By displaying a different set of cell surface proteins on the host cell, your immune system is unable to recognise this new strain of virus, annoyingly bypassing the immune system and causing a new episode of cold symptoms.


It’s only when a virus has reached high enough numbers for a sufficiently long period of time, that the immune system has a chance to develop antibodies that can recognise and kill the virus. If this threshold is higher than that required to cause symptoms, you will suffer from the irksome triad of cough, runny nose and sore throat which typifies a common cold.




The goal of reducing the frequency and duration of these bouts of illness, should therefore be focused on improving the effectiveness of the immune system rather than using vaccines or taking medicine to try and kill the virus.


The strength of the immune system is affected by many different factors, but assuming you’re not suffering from an immunodeficiency, diabetes or taking strong medications to suppress your immune system, you can influence your immune system in several ways.




Firstly, as with any cells in the body, your immune system requires nutritional sustenance. It probably won’t surprise you to hear that eating grains and omega-6 fatty acids can have a detrimental affect on the immune system. These compounds are pro-inflammatory and tend to cause the immune system to over-react to stimulus. Although you might expect this to make the immune system strong, it actually just serves to make it work inefficiently. A bit like trying to kill ants with a machine gun.


It might be a little unexpected to hear that carbohydrates are actually quite good for the immune system, albeit in moderate quantities and of the non-inflammatory type. When people suddenly change to a very low-carb diet after previously eating high levels of carbohydrates, their immune system often suffers and they can become unwell easily. Depending on your goals, it might be sensible to consider keeping some rice and potatoes in the diet to help the body continue to manufacture the immune complexes required to fight some infections



Secondly, the immune system is highly affected by variations in stress level. This includes general psychological stress but also stress from exercise, starvation, too little sleep and also recovering from other illness or injury. Often people who are feeling run down from overworking and sleeping too little are more prone to infections. Over-training at the gym with insufficient recovery times predisposes you to getting ill. This is often potentiated by dieting, when people restrict their calorie intact and increase their exercise output at the same time they leave themselves open to infections which can easily derail an attempt at weight loss.




Another thing which often influences immunity is prior exposure. It was observed when explorers traveled to the new world in the fifteenth century that many natives contracted diseases which were relatively benign in the explorers and suffered much more serious symptoms. The same was true visa versa and conditions such as syphilis became prolific in the explorers’ home countries where no one had previously been exposure to these conditions.


The nature of my work puts me in a fortunate position. I am exposed to many many ill people every day but only for a very short amount of time. Consequently I probably come into contact with the majority of locally circulating viruses, but in small enough initial titres to prime my immune system, but for me not to suffer from the symptoms. I can honestly say I haven’t suffered from an upper respiratory tract infection since I started work as a full time GP about three years ago. The only times I’ve ever felt slightly under the weather is when I’ve gone from a few weeks of minimal exercise to a comparably intense exercise regime.


I think that regular exposure to viruses, ultimately helps strengthen the immune system and reduces severity and duration of illness in the long run. Many people loath taking the tube to work or spending time in the doctor’s waiting room because of the perceived risk of contracting some horrible virus. But I think these exposures should be valued as an opportunity to stress your immune system and defend against a future infection.




Staying hydrated during a viral illness is especially important. When you are unwell and have a high temperature, you lose more fluid via respiration and via the skin. Extra fluids are required to replace these losses. Dehydration limits the effectiveness of the immune system and often makes you feel more unwell.

Supplements and treatments

Various supplements and nutrients are occasionally touted as helping to prevent and speed up recovery from cold symptoms.


Vitamin C


Vitamin C is often taken at the onset of cold symptoms to try and stop it in it’s tracks. However the evidence for using vitamin C in the this way is actually quite poor. It is much more effective if taken prophylactically to help prevent illness in the first place. This effect appears to be magnified in people who are physically active. Doses of between 1-2g daily are advised if you don’t get plenty in your diet.



Zinc is also often used to prevent cold symptoms from getting worse. It is thought that zinc stops viruses from replicating and that if zinc is taken in the first 24 hours of an infection then it helps to reduce the severity of the illness. However, this also has fairly poor evidence and if any benefit is to be derived from zinc, it’s likely to be in people who are already deficient. Zinc shouldn’t usually be taken daily as it can be neurotoxic and it also tends to induce copper deficiency which can increase the risk of prostate cancer.




Garlic is a reliable source for improving immunity. It does little to reduce cold symptoms but is helpful for boosting the immune system if taken regularly. It can be supplemented by taking doses in the region of 600mg-1200mg daily or consumed in meals. Heating the garlic after cutting or crushing it is necessary to release the active compounds. About three cloves daily is ideal if you’re looking to improve your immunity.




Echinacea has some decent evidence that it is useful for both prevention of viral illnesses and also, to a lesser extend, treatment of symptoms when they arise. There is no guarantee that echinacea will work to reduce coughs and colds, but as the evidence goes, it seems to be the closest thing we have to a cure to the common cold. It works by stimulating macrophages and by increasing the production of immunoglobulins. The dose is between 900-1500mg each day.


Andrographis paniculata


The best treatment for a cold to reduce symptoms and duration, might be a herb called Andrographis paniculata which is found in Siberian ginseng. It seems to reduce the duration of symptoms if taken early on, reduce the severity of symptoms and was comparable to paracetamol when used to reduce the symptoms of pharyngotonsillitis. It can be taken as an extraction of the root of the plant in the region of 2000-6000mg daily.


Vitamin D


Vitamin D is also known to improve immune function. Vitamin D is produced in the body following stimulation from sunlight. One of the theories why people tend to suffer from viral illnesses in winter time is due to low vitamin D levels. In the UK the UV index rarely reaches the necessary threshold of 3 in the winter months that’s required for vitamin D production. People also tend to spend less time outside due to the cold weather. The majority of people in the UK are not vitamin D deficient, unless you are housebound or have very dark skin, but most people have suboptimal levels. Supplementing at about 2000 IU per day is my recommendation for keeping your vitamin D levels replete.


So, there you have it. A few tips and tricks to implement to try and stave off the winter coughs and colds this year. With the best will in the world it’s impossible to prevent all viral illness, but on the bright side, when it comes to the immune system, the old adage ‘what doesn’t kill you makes you stronger’, is actually true.

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