Senior nutritionist Rose Carr answers some common questions about how to prevent and treat those unpleasant winter illnesses.
Q: Have I got a cold or the flu? How can I tell?
The flu is more severe than a cold, which is presumably why some people always insist they have the flu and not ‘just a cold’. Both conditions are caused by viruses, (which, despite misconceptions, can’t be treated with antibiotics).
It’s not too hard to tell the difference between a cold and the flu. With a cold you generally start with a sore throat and a few sniffles. While you can get a mild fever at the start of a cold, you often won’t. Over the first few days you may start sneezing more frequently, a runny nose becomes more apparent, the mucus tends to get thicker and you may develop a cough before symptoms finally taper off. The whole process can take a couple of days, or it may be a couple of weeks before it passes.
The flu, on the other hand, is more likely to knock you over and send you right to bed. The first symptom can often be the chills, a headache or an aching body. You’ll have a 38°C or higher fever in the first few days. You may not get the full range of cold-like symptoms, but there’ll be one or two. You’re also likely to be lethargic and even when you are recovering, your energy levels may remain low for a while.
Q: Should I still go to work and ‘soldier on’, or rest up in bed?
While there are plenty of cold and flu tablets available to help suppress the symptoms, rest is the best course of action if you have a cold or flu. You may find you can’t get out of bed for a few days while you have a high fever.
In some work places, soldiering on is encouraged, and with a cold you usually can – but you need to consider how productive you will be and whether you can avoid passing it on to your co-workers. Colds and flu are most contagious in the first few days and can continue to be contagious for up to a week or so. Scrupulous hygiene is the best way to prevent spreading a cold or flu virus. Wash your hands regularly with soap and water and dry them well, or use a hand sanitiser. Make sure you always cover your nose and mouth with a tissue when coughing or sneezing, then bin your used tissues.
Q Is it true you should ‘feed a cold and starve a fever’?
No. A fever speeds up your metabolism – so even though you may be resting, your body needs energy and nutrients from food to help fight the illness. When you have a cold you may find you have a reduced appetite – especially if you are all blocked up and can’t smell your food – but your body needs energy and nutrients to fight off a cold virus, too.
Q What can I eat and drink for a speedy recovery?
Once you’ve come down with a cold or flu, what you eat and drink may help you feel better, but it won’t necessarily shorten the duration.
Fluids are the most important. If you have a fever, you’re more prone to dehydration. Sipping fluids often will keep the lining of your nose and throat passages moist and the mucus fluid. Warm fluids – such as the traditional chicken soup or hot water with lemon and honey – can help to clear nasal passages and may help soothe a sore throat. Herbal teas, juice, water and soups help keep fluids up, but limit or avoid caffeinated drinks and alcohol, which can be dehydrating.
When it comes to food, it depends on what you can handle eating, but go for nutrient-dense foods such as porridge, fruit smoothies or vegetable soup with dry wholegrain toast.
Q: Should I go to the gym and ‘sweat it out’?
Not if you have a fever! Your pulse rate and temperature are already elevated, so you don’t want to increase them by exercising. Exercise is also not advised if you have chest congestion or a cough.
However, if all of your cold symptoms are above the neck, exercise is fine. Researchers have found that the lung capacity of people with a cold is the same as when they’re healthy, and exercise doesn’t feel any more strenuous. You may even feel better after exercising – it may clear the nasal passages – but there’s no evidence it will have any effect on the duration of the cold.
Always listen to your body and if your symptoms get worse when you exercise, skip the gym until you feel better.
Q: How can I prevent getting a cold or flu?
When it comes to viruses, prevention is the best cure. An adequate intake of a range of vitamins and minerals is essential for your immune system to perform at its best. It’s recommended that you get your vitamins and minerals from food (as opposed to supplements) so you also get the protective phytochemicals and macronutrients they contain. A varied diet, with plenty of fruit and veg, is your best defence.
High levels of stress and a lack of good quality sleep can also affect your immunity and make you more vulnerable to colds and flu. One of the best ways to keep stress at bay is through regular exercise, which will help you sleep better, too.
Q: Should I take vitamin C, zinc, echinacea, or any other supplements to help me get over my cold?
There’s no solid evidence for or against taking supplements when it comes to preventing or recovering from a cold, but here are some of the latest findings on a few of the most common “coldbeating” supplements.
While a few studies on marathon runners, skiers and soldiers participating in a sub-arctic exercise found vitamin C can help prevent colds, other studies show that if you’re not going to be subjected to severe physical or cold stress, then taking vitamin C won’t have any effect on how many colds you catch. However, other studies have found taking high doses of vitamin C before the onset of a cold reduced its duration and severity.
Pooling these studies, it’s estimated that taking at least 200mg vitamin C daily might mean adults suffer for 11 days each year with a cold rather than 12 days; and for under-12s, who experience more colds, it could mean 24 days a year with a cold rather than 28 days. In studies where high doses of vitamin C were taken after cold symptoms began, there was no consistent effect on either the duration or severity of symptoms.
The different effects may depend on how much vitamin C is in your usual diet, so we recommend regularly including foods rich in vitamin C, such as kiwifruit, capsicum, broccoli, cauliflower, strawberries and citrus fruits.
There is evidence that garlic has antibacterial and antiviral properties, but there are few studies on garlic’s effect on colds. In one study, people who took a garlic supplement every day for three months had fewer colds than those taking a placebo and the duration of their colds was also reduced. However, more research is needed in order to make these results conclusive.
There’s some evidence that preparations from the flowering parts of Echinacea purpurea may be effective in the early treatment of colds for adults. Results are inconsistent, but if you are going to use echinacea, it is best to start taking it as soon as you feel a cold coming on. It may help lessen the severity and duration of your cold. You could take it as a preventative measure, as it won’t do you any harm, but it’s not yet proven whether or not Echinacea can prevent a cold.
The jury’s still out on whether or not zinc is effective as a cold remedy. If you choose to use zinc, be careful, as doses above 40mg (from food and supplements combined) can have adverse effects. You can get plenty of zinc from foods such as seafood (especially oysters), meat and poultry, milk and dairy products, tofu, silverbeet and wholegrains.
We asked the HFG experts, our Editorial Advisory Board members, if they take any supplements (and which ones) to treat or prevent colds or flu.
Dr Tim Crowe:
“The only one I take is vitamin ‘OJ’. Orange juice is a good source of vitamin C. The clinical evidence shows that while dosing up on vitamin C appears to do little in helping prevent colds, it may help lessen the duration you have to put up with a cold.”
Samir Samman, PhD:
“I don’t get cold or flu often enough to worry about it. But I am aware that there is good evidence that nutrients, such as zinc and vitamin C, help to reduce the duration of cold/flu symptoms by about half to one day.”
Glenn Cardwell, APD:
“I rarely get a cold… Eat well, be fit and get some sunshine is my guiding mantra. I don’t take any supplements, even if I get the sniffles.”
Professor Jennie Brand-Miller:
“I don’t take any supplements at all, even to treat a cold, although I’m happy to take an antihistamine over the short term to reduce nasal congestion. I am cautious with supplements because they can contain unintended contaminants. Supplements don’t have the same degree of regulation over manufacturing as drugs do.”
Dr Gary Deed:
“The common cold typically means a mild viral upper respiratory illness (URTI), with some sore throat, controllable temperature and some lethargy. Still, confusion reigns and many people think they can relieve it with antibiotics! For a viral URTI, I take zinc lozenges, based on a recent “Cochrane collaboration review”. It’s nice to see evidence leading us to have choices for interventions that work.”
Dr Helen O’Connor:
“I think factors such as early rest are important. Often individuals only rest when they are quite sick. My understanding is that early rest can decrease the severity of symptoms and result in faster recovery.”
Dr Janet Franklin:
“As soon as you start to feel any niggle of a sore throat, rest (i.e. go to bed a bit earlier or sleep in a bit longer). Plus, make sure you are eating a well-balanced diet full of fruit and vegetables, lean meats and low-GI carbohydrates to boost your immunity. Lozenges with zinc and echinacea might help some people if taken from the first signs of illness.”
Did you know? Research has found the flu vaccine is less effective in older people but regular exercise can improve its effect.
Did you know? Immunity can be reduced for a while after vigorous exercise. You’re more susceptible to getting an upper respiratory tract infection after running a marathon than after going for a walk around the block.