Colds and Flu – Keeping Well in the Winter Season
Virtually everyone has a theory about colds and flu and, given the glut of information, it may be hard to separate the facts from plain fiction. Yet, there are data that show what makes us vulnerable to these infections, and how to stay well when the weather turns cold.
Susceptibility and stress
Catching the flu is not a random event. Bugs may be getting nastier (see box below), and our poorly ventilated, sometimes crowded, environments may encourage the spread of virulent viruses. But if exposure were the only factor, all of us would get sick every time we were exposed.
In truth, many people in a room may be exposed to a cold or flu virus, but only some become infected. Susceptibility, not exposure, is the key and is likely to be influenced by a number of things.
People who have heart complaints, asthma, chronic kidney disease or diabetes, or who are taking medications (for instance, steroids) are more susceptible to colds and flu. Smokers are also more susceptible to upper respiratory tract infection (URTI; Am J Public Health, 1993; 83: 1277-83).
But predicting susceptibility in an otherwise healthy population is less straightforward. Nutritional status and exercise play a role (see boxes, pp 2 and 3) but, recently, a great deal of study has focused on the role of stress.
The ability of stress to alter immune function, and precipitate and aggravate infectious diseases has long been recognised (J Fla Med Assoc, 1993; 80: 409-11). Today, there is strong evidence that the single biggest risk factor that puts otherwise healthy people at risk of catching a cold may be stress.
In one study, after determining their stress levels by questionnaire, 394 subjects were exposed to common rhinoviruses (the virus causing the common cold). Only 27 per cent of the low-stress group showed clinical symptoms compared with 47 per cent of those at the high end of the scale (N Engl J Med, 1991; 325: 606-12).
In another study, 276 subjects, who had been carefully evaluated for their level of involvement in one or more of a dozen types of social ties – for example, with a spouse or partner, sibling, parent, close friend or fellow worker – were given nasal drops containing rhinoviruses.
Susceptibility to colds was reduced as social support increased. Of those with three or less relationships, 62 per cent came down with a cold compared with only 35 per cent in those with six or more types of social support (J Am Med Assoc, 1997; 277: 1940-4).
A repeat of that study (Health Psychol, 1998; 17: 214-23) evaluated stress more precisely (long term vs short term) as well as the severity of illness, and also measured blood levels of natural-killer (NK) cells, the immune system cells that combat infectious agents. Those stressed for more than a month had lower NK-cell activity and were 2.2 times more likely to develop colds. The biggest risk came with increased job stress.
Stressed children have a greater susceptibility to URTI and show measurable decreases in mucosal immunity (J Psychosom Res, 1997; 43: 271-8). Depression is also strongly related to catching a cold (Epidemiology, 2001; 12: 345-9).
Prescription drugs, like antibiotics, can also increase colds/ flu susceptibility. A substantial number of GPs still prescribe antibiotics for colds/flu, even though these drugs don’t work against viruses (J Am Med Assoc, 1997; 278: 901-4; J Am Med Assoc, 1998; 279: 875-7).
Australian doctors report that flucloxacillin, a semisynthetic penicillin, can cause cholestatic jaundice (Med J Aust, 1989; 151: 701-5), though its relation to the drug may go unrecognised because of a delayed onset (Lancet, 1992; 339: 679). Older patients and those receiving flucloxacillin for more than two weeks are particularly at risk (BMJ, 1993; 306: 233-5).
Newer combination antibiotics such as Septrin – trimethoprim and sulphamethoxazole, or co-trimoxazole – have been linked with skin rashes and blisters (Ind J Derm, 1982; 48: 207-8; Br J Dermatol, 1987; 116: 241-2; Dermatology, 1986; 172: 230-1), and a host of HIV-like symptoms, including anaemia, loss of appetite, nausea, vomiting, numbness, convulsions, chills, fever, swollen glands, and ulcers in the mouth, eyes and urethra.
Overuse of antibiotics also contributes to the emergence of ‘superbugs’, and can deplete the friendly gut bacteria needed to maintain good health and immunity. Clearly, when you take antibiotics, you are risking a trade-off of symptoms which may leave you more unhealthy than you were before.
Over-the-counter madness
If you do succumb to a cold or flu, there are literally hundreds of over-the-counter (OTC) remedies that claim to relieve cold symptoms, but most have been proven useless (J Am Med Assoc, 1993; 269: 2258-63). The most popular varieties use a scattergun approach, mixing several different types of ingredients, often resulting in a variety of side-effects. For instance:
Nasal sprays containing phenylephrine hydrochloride, oxymetazoline hydrochloride or xylometazoline hydrochloride may clear the nose initially but, after a few days, their continued use can cause a rebound effect, producing worse nasal congestion than before.
Oral decongestants stimulate the sympathetic nervous system and can increase blood pressure and pulse – risky for those with hypertension. They can cause heart rhythm disturbances, anxiety and a rebound effect. Perhaps the worst offender is phenylpropanolamine (PPA). In one study, this chemical increased the risk of stroke in women more than threefold (N Engl J Med, 2000; 343: 1826-32). This was the last straw in more than a decade of studies of PPA. The US Food and Drug Administration (FDA) has asked drug companies to stop marketing products containing PPA but, in the UK, it is still widely found in cold remedies.
Antihistamines may reduce a runny nose and sneezing, but have a minimal effect on other symptoms. They can have a sedating effect and are often added to multisymptom cold remedies because of their ability to counteract the stimulant effect of decongestants.
Cough suppressants such as guaifenesin (Robitussin) and dextromethorphan (NyQuil or Night Nurse) show no efficacy in suppressing coughs. The latter has been associated with liver damage and is used by teenagers to get a ‘poor man’s high’. Codeine also doesn’t suppress coughs, but can result in constipation.
Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, paracetamol (acetaminophen) and ibuprofen may in fact increase nasal symptoms. There is also evidence that aspirin decreases the antibody response in rhinovirus infections (J Am Med Assoc, 1975; 231: 1248-51; J Infect Dis, 1990; 162: 1277-82). Furthermore, the influenza virus grows best at 34-35º C, but poorly – if at all – at temperatures greater than 37º C. So reducing fever with NSAIDs may simply prolong the agony of a cold or flu.
To jab or not to jab?
Predicting a flu epidemic is not an exact science, as was elegantly illustrated in 1976 when US officials, spurred on by illness among soldiers at Fort Dix, New Jersey, predicted a swine flu epidemic as lethal as the great flu pandemic of 1918. In the event, rates of flu and pneumonia-related deaths in 1976 were at their lowest in years (MMWR, 1976; 25: 391-2), much to the chagrin of the government, which had spent millions preparing a vaccine.
As flu can be caused by any of hundreds of strains of myxovirus, which mutate more or less constantly, vaccination amounts to a kind of biological Russian roulette. Even if the vaccine is for the right strain of myxovirus, for reasons not yet fully understood, you may not respond by producing anti-bodies to it. One study found that 30-40 per cent of elderly people do not respond to vaccination (Hum Immunol, 1994; 40: 202-9), and even if an immune response occurs, there is doubt as to whether this reduces the incidence of influenza (Vaccine, 1994; 12: 1185-9).Studies into the efficacy of the flu vaccine show mixed results (Gerontology, 1995; 41: 3-10), and questions remain as to whether the inactivated virus used in the vaccine can truly provide complete protection (Int Arch Allergy Immunol, 1995; 108: 318-20).
Then there are the side-effects. While authorities say these are rare, this is cold comfort if you are among those affected. The ill-fated swine flu vaccine resulted in a rise of Guillain-Barré syndrome, a type of paralysis (Am J Epidemiol, 1979; 110: 105-23). In one UK study, around one in 12 patients said the flu vaccine was a trigger for asthma attacks (Lancet, 1998; 351: 326-31). Optic neuritis and permanent blindness, vasculitis and joint problems, reversible paralysis and myelopathy have also been reported (Am J Ophthalmol, 1997; 124: 703-4; J Rheumatol, 1997; 24: 1198-202; Ned Tijd Geneeskunde, 1995; 139: 2152-4; Muscle Nerve, 1995; 18: 1199-201).
Reviews of the benefits of vaccines in healthy adults have shown that these are negligible, sucessfully reducing the number of virus carriers (as shown by blood tests), but not of those who actually develop the flu (Cochrane Database Syst Rev, 2000; [2]: CD001269; Vaccine, 2000; 18: 957-1030).
Vitamin C, zinc and Echinacea
Research shows that most of us treat colds and flu at home (J Fam Pract, 1998; 47: 366-9). Decades of research have gone into vitamin supplementation and immunity, and many nutrients have proved to be important in shoring up our immune defences (see box below).
The most popular of these are vitamin C and zinc, although opinion varies regarding their true effectiveness. In the 1970s, Linus Pauling’s review of the evidence concluded that large doses of vitamin C prevented colds and alleviated symptoms (Proc Natl Acad Sci USA, 1971; 68: 2678-81).
Since that time, however, the efficacy of vitamin C has been hotly debated. A 1975 analysis by Thomas Chalmers concluded that the case for vitamin C had “questionable validity” (Am J Med, 1975; 58: 532-6), but a recent analysis of the report suggests that his analysis was seriously flawed (J Am Coll Nutr, 1995; 14; 116-23).
It is now generally accepted that a dose of 1-8 g of vitamin C daily can decrease the severity of cold symptoms by an average of 23 per cent and reduce the duration of illness by nearly half (Scand J Infect Dis, 1994; 26: 1-6; Br J Nutr, 1992; 67: 3-16).
More recent reviews of the evidence say that, while vitamin C can alleviate cold symptoms, taking large doses is not preventative (Cochrane Database Syst Rev, 2000; [2]: CD000980). However, some groups may benefit from regular supplementation, such as athletes under heavy physical stress (Int J Sport Med, 1996; 17: 379-83). One review suggests a reduction in cold incidence of up to 50 per cent with regular vitamin C use (Int J Tuberc Lung Dis, 1999; 3: 756-61).
Zinc has long been promoted as a remedy and preventative for colds and flu. In one study, a nasal gel containing zinc significantly shortened the duration of a cold if taken within 24 hours of the onset of symptoms (Ear Nose Throat J, 2000; 79: 778-80, 782).
Sidebar: Are viruses getting worse?
Nobody can say with any certainty whether viruses are getting ‘worse’. They are, however, extremely adaptable organisms, and it is the way viruses are able to exchange genetic material as well as adapt to different hosts that holds the key to their apparently increasing virulence.
The influenza virus, which is an RNA virus, can mutate up to a million times more often than a DNA virus. Only the human immunodeficiency virus (HIV), supposedly another RNA virus, mutates faster.
In addition to ducks, the influenza virus is also able to infect pigs as well as humans. Strains of duck, human and pig viruses can easily swap genetic material. If a host becomes infected with two or more viruses simultaneously, they can rapidly mutate into new and never-before-seen strains. If one virus is extremely communicable while the other is extremely lethal, the mixing and matching of their genes could produce a lethal hybrid. This is what scientists speculate happened in 1918.
New evidence from Australia suggests that the Spanish flu pandemic of 1918 that killed so many healthy people in their prime was a mutation of human and pig strains of influenza. The researchers’ findings are based on a reexamination of gene fragments of the 1918 flu virus, extracted from the preserved tissue of two soldiers who died from it and the lungs of a third victim who was exhumed after 80 years from a grave in the permafrost soil of Alaska (Science, 2001; 293: 1842-5).
As long as we continue to provide environments where viruses from different hosts can easily mix and exchange data (for instance, the Oriental practice of hanging duck cages above pig sties so that the pigs can feed on the avian faeces), viruses will continue to take advantage of this and grow ever more powerful.
Sidebar: Fighting winter lethargy
Sitting at home by the fire in the dead of winter is a comfortable pastime, but it may also be one reason why we get sicker at this time of year. There is a wealth of research that links regular moderate exercise with an improved immune function and reduced susceptibility to the common cold (Exerc Immunol Rev, 1997; 3: 32-52; Sports Med, 1994; 17: 86-107). Analyses of blood from older women who exercise regularly have also shown greater immune activity than the blood of those who do not (Mech Ageing Develop, 1997; 93: 215-22).
However, exercise – like everything else – has a downside. While regular moderate exercise is helpful, bursts of heavy exercise once in a while may be harmful, suppressing immunity for several hours and creating a period of vulnerability when the risk of upper respiratory tract infections is increased (Int J Sports Med, 1994; 15: S131-41). Interestingly, the soldiers most severely affected by the US swine flu outbreak of 1976 were just beginning basic combat training, a time of exceptional exertion (J Infect Dis, 1977; 136 [Suppl]: S363-8).
Sidebar: Nutrients that aid immunity
For a properly functioning immune system, consider the following nutrients:
Vitamin A can reduce the incidence and severity of infectious illnesses (Clin Infect Dis, 1994; 19: 489-99; J Nutr, 1995; 125: 1211-21). The usual dose is 8000-12,000 IU daily.
B-complex vitamins such as B6, B12 and folic acid support immune function and are especially useful for stressed individuals (J Am Med Assoc, 1981; 245: 53-8; Clin Sci, 1984; 66: 241-8). Daily doses range from 25-100 mg as part of a complex
Vitamin C is the best-known immune-enhancing nutrient (see main story). Aim for 1000 mg daily.
Vitamin E significantly decreases susceptibility to infections. Supplementation can benefit both the healthy and the ill (Arch Immunol Ther Exp, 1987; 35: 207-10; Ann NY Acad Sci, 1989; 570: 283-90). A daily dose should be around 200-400 IU
Ubiquinone (coenzyme Q10) can compensate for immune deficiencies due to ageing or disease (Med Hypoth, 1992; 38: 315-21; Mech Ageing Develop, 1978; 7: 189-97). Daily doses range from 20-200 mg.
Zinc gluconate has shown a modest benefit on the duration of cold symptoms whereas zinc acetate did not (Clin Infect Dis, 2000; 31: 1202-8). Daily doses range from 15 mg for prevention to 100 mg during an infection.
Selenium if deficient has been associated with lowered immunity. Its role as an antioxidant may be an important factor (Fed Proc, 1979; 38: 2139-42). Try 25-100 mg daily.
Probiotics are technically not nutrients, but have a role in improving immune function (Immunopharmacol Immunotoxicol, 1992; 14: 331-40; Int J Immunother, 1993; 1X: 23-8). Supplements should contain at least three billion viable bacteria per capsule.
Sidebar: Treating colds and flu naturally
Take action at the first signs of a cold or flu as most of the research into remedies administer these early on to optimise the benefits.
Reach for garlic. Fresh and raw garlic (Allium sativum) is best, but if you take supplements, use those made from dried garlic and not the steam-distilled variety (which has little or no beneficial alliicin). In a study involving 146 subjects taking garlic or placebo for 90 days during the cold season, nearly three times as many of those taking placebo caught a cold compared with those taking a daily garlic preparation. In addition, those with a cold taking the garlic appeared to recover more quickly (Adv Ther, 2001; 18: 189-93).
Meditate, don’t medicate. Stress-reducing therapies, such as hypnosis, have been found to improve immune function (J Consult Clin Psychol, 2001; 69: 674-82; Int J Psychophysiol, 2001; 42: 55-71). Meditation and yoga may achieve similar results. Relaxation has proved effective in treating recurrent symptoms of cold and flu in children (J Psychosom Res, 2001; 51: 369-77; J Dev Behav Pediatr, 1996; 17: 311-6).
Try homoeopathy. L52, a combination of 10 homoeopathic remedies taken in drops, has proved successful in treating colds and flu in two large-scale trials in France (Lecocq P, Flu Treatment, Metz: Editions Lehning, 1988). However, the low dilutions are low and, as it contains several known poisonous plants, some homoeopaths recommend other alternatives
Oscillococcinum 200 is prepared from diluted Barbary duck heart and liver. Anecdotal evidence suggests that it is effective for flu if taken within 48 hours of symptom onset. Controlled trials in France (Gaier H, Thorsons Encyclopaedic Dictionary of Homeopathy, London: HarperCollins, 1991) found it effective for controlling fever, cough, runny nose, muscle and joint stiffness, and chills. These findings were supported by others on a larger scale (Br J Clin Pharmacol, 1989; 27: 329-35).
A recent review of Oscillococcinum concludes that it ‘probably’ reduces the duration of illness in patients with flu symptoms, but is unlikely to be a preventative, although the authors acknowledge that data on this remedy are lacking (Cochrane Database Syst Rev, 2000; 2: CD001957).
You need a doctor’s prescription to get Oscillococcinum in the UK, but Ainsworth’s Homoeopathic Pharmacy (020 7935 5330) produces their own version called Anas barb and operate a mail-order service. Ainsworth’s also produces an anti-cold and flu remedy combining Bacillinum and Influenzinum which is updated every year to cover the latest flu strains.
A German trial comparing homoeopathic Eupatorium perfoliatum D2 with aspirin found that both treatments were equally effective in relieving cold and flu symptoms (Arzneim Forsch, 1981; 31: 732-6)
Stay hydrated with water, herbal teas and even chicken soup (Chest, 2000; 118: 887-8). Consider also herbal teas such as nettle and Echinacea. One study found that Echinacea herbal tea was more effective than a placebo for relieving cold/flu symptoms (J Altern Complement Med, 2000; 6: 327-34)
Steam inhalation may make you feel better (Chest, 1991; 99; 1352-6; J Am Med Assoc, 1990; 264: 989-91), although two large-scale trials concluded it did not relieve cold symptoms (J Am Med Assoc, 1994; 271: 1109-11; 1112-3)
Limit the spread of microbes. Covering your mouth when you cough or sneeze seems obvious, but it’s amazing to see how many people don’t do it. When you cough or sneeze, vapour containing infectious microbes is expelled at over 120 mph, easily reaching most people in your immediate vicinity. In fact, rhinoviruses are spread chiefly by vapour and not by personal contact (Eur J Epidemiol, 1987; 3: 327-35).
- This article first appeared in the November 2001( volume 12, number 8) edition of What Doctors Don’t Tell You.
