Seven brilliant supplements to prevent colds and flu

Soldiering through the winter months is battle of sneezes and sniffles, but here experts explain which supplements provide the best defence

If you haven’t had a cold recently, you’re doing well. According to the National Institute for Health and Care Excellence (NICE), adults get two or three colds per year, while children catch between five and eight. But, as parents and teachers know, those who are in close contact with children get more than their fair share. And, as we get older, our immune system isn’t as robust, so people over 65 are more susceptible, too. 
Although there’s no generally accepted explanation for why we get more colds in winter, one study found that up to 80 per cent of cold infections are caused by rhinovirus (HRV), and research indicates that rhinovirus incidence peaks in early autumn and late spring. 
Most of us try to battle through a cold with over-the-counter cough, cold and sore throat treatments – even though there’s limited evidence that they actually work. We can also turn to dietary supplements in a bid to boost our immune system and shake off symptoms fast – these are the ones to take. 
“When it comes to the treatment of colds, there is some evidence that vitamin C can reduce the length of time that symptoms last,” says Bridget Benelam, a nutrition scientist at the British Nutrition Foundation. Indeed, one study found that taking 1-2mg of vitamin C daily cut the duration of colds by 8 per cent for adults and 14 per cent for children, as well as reducing the severity of symptoms. 
Charlotte Faure Green, a registered nutritionist with the British Association for Nutrition and Lifestyle Medicine, explains: “Taking vitamin C when you first notice symptoms of a cold may reduce its duration by approximately 24 hours. This may be by supporting the production of antibodies – the proteins that target and neutralise specific pathogens in the body.”
The NHS recommends that we should all consider taking a vitamin D supplement during the autumn and winter – and people at high risk of vitamin D deficiency (such as young children, the elderly, those who don’t go outside much, who cover their skin, or who have dark skin that absorbs less sunlight) should supplement all year round.
Research indicates that taking a regular vitamin D supplement through the winter halves the risk of respiratory infections, including colds, flu, bronchitis and pneumonia, among people with low levels of vitamin D in their body. It can also cut the risk of infection by 10 per cent for those who already have higher vitamin D levels. 
However, Vitamin D is unlikely to help when you’re already experiencing symptoms. “If you have a vitamin D deficiency and you get a cold, you’re probably not going to be able to top up your levels particularly quickly,” explains Dr Simon Clarke. “If you cram yourself full of vitamin D tablets, you’ll probably just pee it straight out. You need to think ahead and take them for at least a week or two before there would be any impact on your immunity.”
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Many people swear by over-the-counter zinc products to help prevent or relieve colds. Recent research found that zinc supplementation shortened the duration of colds by an average of two days, and reduced the severity of symptoms. Other research found that it supports mucous membrane integrity and has an antiviral effect.
Charlotte Faure Green says: “Zinc is essential for the development and proper functioning of various immune cells, which are instrumental in identifying and eliminating viruses when we encounter them. Ensuring sufficient zinc intake year-round, not just in cold and flu season, will ensure that our immune cells and barrier defences are raring to go.”
Studies show that low levels of vitamin B6 can affect our immune response to a wide range of diseases and infections, from the common cold to cancer. It has recently been found that low levels can increase the risk of complications associated with Covid-19, and supplementation can also have a calming effect that reduces stress and anxiety, both of which can impact our immune system. 
Charlotte Faure Green explains: “Vitamin B6 is essential to produce antibodies, and adequate levels are necessary for the body to generate a robust antibody response to infections. It’s also important for the proper functioning of the adrenal glands, which produce stress hormones like cortisol. Chronic stress can weaken the immune system over time, and vitamin B6 helps manage this, indirectly supporting our immune function.”
There are numerous lesser-known supplements that are believed to have immune-boosting or anti-inflammatory effects, all of which have the potential to help us avoid colds or ease symptoms. And, without a cure for the common cold, many of us will give anything a try.
One of the most popular is echinacea, which studies have found can reduce the frequency and severity of colds – and may help with prevention if you seem to pick up one bug after another. 
Research shows that garlic supplements could help to reduce the risk of getting a cold by 65 per cent, and one study found it could make colds shorter and less severe. Elderberry may have a similar effect: it appears to reduce the duration of a cold by a day or two. 
Ginseng is another commonly used supplement that has been studied for its immune-boosting properties, but it can interact with common prescription medications, so it’s important to check with a pharmacist before using it, and only take it for a short time to minimise the risks of side effects.
“There’s an emerging body of research exploring the effects of creatine on the immune system,” says Charlotte Faure Green. “Typically used as a sports-enhancement supplement, it may positively impact molecules responsible for detecting infections. It may also reduce post-infectious inflammations, though more research is needed.”
Charlotte adds: “Ashwagandha has been used for centuries in traditional Ayurvedic medicine for its potential health benefits, with a focus on its stress-busting properties. While scientific research on its specific impact on the immune system is ongoing, there is evidence to suggest that it may play a role in overall immune system support.”
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Before you think about spending money on supplements, experts recommend taking a look at your lifestyle, as this does have an impact on your chances of picking up a winter bug. “The best thing to do is get proper sleep and make sure you’re eating well before we get into winter,” says Dr Simon Clarke, an associate professor in cellular microbiology at the University of Reading. 
One study found that getting less than seven hours of sleep each night makes you up to three times more likely to come down with a cold than people who get a full eight hours, while extensive research shows that stress hormones can affect your immune system, leaving you more vulnerable to infection. Researchers from Yale University found that smokers are not only more likely to catch a cold, but to take longer to shake it off. 
Despite some evidence that supplements like vitamin C and zinc can reduce the duration of a cold, there’s not much that any of them can do to prevent it completely once the sniffles start. “These things are hit and run viruses, so once you’ve got that feeling that you’ve got a cold coming, it’s probably too late,” warns Dr Simon Clarke. 
However, Dr Clarke admits that he always reaches for Vicks First Defence when he notices cold symptoms. “It snares the virus in your upper airways and nasal cavity and stops it spreading. From personal experience, I’d say it works about 80 per cent of the time, but you have to catch it incredibly early,” he explains. 
Many of us believe we’ve got influenza when we’re actually suffering from a nasty cold. According to the NHS, cold symptoms usually come on gradually over a day or two, and include a scratchy or sore throat, blocked or runny nose, sneezing and cough. Flu symptoms come on quickly and are more severe. These include a sudden fever, headache, chills, aching muscles and fatigue. 
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