10 cold prevention remedies proven by science

Cold prevention on your mind as those pesky sore throats and annoying sniffling colleagues start to plague us once again? Anna Magee has the answers

Some 70 per cent of us will get a respiratory infection each year, making these most common reasons we go to a GP. That means trying to prevent yourself catching that horrendous lurgy is a tall order.

It’s why we have looked at the ways we can boost our immunity and help prevent coughs, colds and flu that have a solid scientific basis.

Cold prevention remedy #1: Eat a rainbow coloured diet

Eating a diet rich in lots of different fruits and vegetables will ensure you’re getting plenty of antioxidants into your diet.

The key immune-boosting ones are vitamins A, C, D, zinc, selenium and bioflavonoids and they’re found in brightly coloured and green vegetables.

Vitamins A, C, D, as well as zinc and selenium help to make our white blood cells more effective at fighting off invaders like bacteria and viruses and in doing so, contribute to the normal functioning of the immune system, asserts nutritional therapist Ellie Isom.

‘Vitamins A and C can be found in a wide range of fruit and vegetables, whereas vitamin D, because it is fat soluble is found in food such as oily fish, dairy and eggs [see #4]. Zinc can also be sourced from these foods, as well as beans, pulses, nuts and seeds [see #10].

Indeed, a review of 83 clinical studies published in July this year in the American Journal Of Clinical Nutrition looked closely at the body of evidence on the subject and concluded that ‘high intakes of fruits and vegetables lead to both a reduction in pro-inflammatory biomarkers [which can promote illness] and an enhanced immune cell profile.’

‘A bright and colourful diet is often recommended to help support and boost the immune system,’ says Isom.

‘The colours within these foods are beneficial components, as well as their vitamin and mineral content,’ she explains.

Especially helpful for immunity are plant pigments such as flavonoids found in rosehip, bilberry and other berries, carotenoids found in foods such as carrots and sweet potatoes, as well as rutin and hesperidin that are naturally found in citrus fruit, and lycopene naturally found in tomatoes, strawberries and cherries.

‘These nutrients are antioxidant molecules that can prevent damage to cells and tissues, and reduce inflammation,’ says Isom.

Cold prevention remedy #2: Get enough sleep

You have probably heard about the importance of getting enough sleep a million times before, but have you ever linked your insomnia problem to those recurring sore throats?

In a fascinating study published last year in the journal Sleep researchers took blood samples from 11 pairs of identical twins with different sleep patterns and discovered that the twin with shorter sleep duration had a depressed immune system, compared with his or her sibling.

‘Sleep is our body’s golden opportunity to rest and repair, and poor sleep is a common driver of a weakened immune system,’ says Isom.

‘Establishing a regular sleep-wake cycle – for example, 10pm sleep, 7am wake, avoiding technology in the hour or so before bed, and making sure you sleep in a dark room with blackout blinds and eye mask if needs be, alongside increasing your intake of calming nutrients such as magnesium and theanine, can be a great starting point,’ she asserts.

The best sources of magnesium include green leafy vegetables, nuts, seeds, beans and pulses to name a few. ‘However, for therapeutic levels we would recommend supplementation’.

‘The best source of theanine is green tea,’ says Isom. ‘However, this may be stimulating for some individuals to consume before bed due to the caffeine levels in which case to help improve sleep, we would again recommend supplementation’.

Cold prevention remedy #3: Exercise

It works for just about everything, but research has often been divided as to whether exercise can improve your immune system.

Some experts believe exercise can help release potential pathogens by keeping the lymphatic system moving, which encourages the body’s detoxification through the lungs and skin through increased breath capacity and sweat. Any gym junkie will tell you they get fewer colds or just ‘sweat them out.’

But while for years it was believed that strenuous exercise (the intensity and amounts elite athletes do) could dampen your immune system, a study from the University of Bath published in April this year in the journal Frontiers in Immunology challenged this idea.

The authors analysed the research available and reinterpreted it, concluding that intense exercise – instead of dampening immunity – may instead be beneficial for immune health.

The authors suggested that low numbers of immune cells in the bloodstream in the hours after exercise are – far from being a sign of immune-suppression – in fact a signal that these cells, primed by exercise, are working in other parts of the body, which has an immuno-protective effect.

According to Harvard Medical School, ‘For now, even though a direct beneficial link hasn’t been established, it’s reasonable to consider moderate regular exercise to be a beneficial arrow in the quiver of healthy living, a potentially important means for keeping your immune system healthy along with the rest of your body’.

Cold prevention remedy #4: Take Vitamin D

Last year, a major global study published in the British Medical Journal suggested that adding more vitamin D to your diet could significantly cut NHS costs, by reducing the risk of colds, flu and other dangerous respiratory infections such as pneumonia and bronchitis.

The study, undertaken by Queen Mary University of London, reanalysed data from 25 clinical trials involving around 11,000 people from 14 countries.

The authors suggested their work settles the question of whether an increase in colds and flu in the winter is partly due to a vitamin D deficiency in the winter.

The consumption of vitamin D supplements daily or weekly showed an immunity benefit in everybody involved in the research, but particularly for those who have low levels, don’t get outside much, cover themselves against the sun or for religious reasons, or have dark skins which absorb less sunlight.

So what’s going on?

‘Immune cell function is highly dependent on vitamin D metabolism,’ says Ellie Isom. ‘Deficiency in vitamin D is associated with increased susceptibility to infection’.

‘Vitamin D enhances the immune system’s ability to recognise pathogens and initiate a response against them, especially influenza (which causes the flu), and respiratory tract infections,’ says Isom.

‘As our sun exposure becomes very limited during winter, it is essential to supplement vitamin D to prevent deficiencies and boost immunity’.

Despite its importance, vitamin D deficiency is unfortunately very common, particularly within the UK, and statistics show that up to 25 per cent of the general UK population may be deficient in vitamin D.

‘This is mainly due to our lack of sunlight exposure along with a low intake through the diet, especially for those who follow a vegetarian or vegan diet,’ says Isom.

Other factors which further contribute towards low vitamin D levels include old age, pregnancy and breastfeeding, dark or covered skin, sunscreen use, obesity and the intake of certain medications.

Vitamin D can also play a role in bone health and mental health, as well as the above mentioned immune health, so deficiency symptoms can be broad and range from increased susceptibility to infections, slow wound healing, low mood and tiredness as well as achy joints/bone pain.

‘If you’re supplementing, the dose would be dependent on what your levels are like to begin with,’ says Isom.

Vitamin D levels can be determined by a blood test from your GP or can be done via private testing, as well as finger print testing which can be ordered online from reputable companies such as BetterYou.

Government recommendations for vitamin D are 10 micrograms (600iu) per day to avoid deficiency, however higher levels can be supplemented, especially during the winter months and in those with a higher risk of deficiency.

‘The research suggests that vitamin D in the form of D3 is the more affective from of this nutrient,’ says Isom.

‘Additionally, supplementing with an emulsified vitamin D supplement, as it is a fat soluble nutrient, can further help to maximise absorption, especially for those with digestive issues,’ she suggests. Try BioCare’s Nutrisorb Liquid BioMulsion D which provides 1000iu of vitamin D a serving.

Cold prevention remedy #5: vitamin C

Vitamin C has been hailed a cold and flu preventative for decades, but what does the science say?

Last year, a report published in the journal Nutrients concluded that, ‘Vitamin C appears to be able to both prevent and treat respiratory and systemic infections by enhancing various immune cell functions…at levels of 100-200mg a day.’

But in 2013, a Cochrane Review wasn’t as straightforward. Cochrane Reviews are released by a global network of scientists, medics and other professionals in 130 countries that look at the body of research on a given topic.

Their 2013 review looked at placebo controlled trials on vitamin C and the common cold on over 11,000 trial participants.

They concluded that routine supplementation for prevention of colds didn’t have enough evidence behind it.

On the other hand, if you’re under a lot of stress and especially if you exercise a lot, the findings suggested supplementation with vitamin C could halve the risk of colds.

Moreover, when it comes to shortening the duration of colds and flus, the report asserted that supplementing with high dose vitamin C as soon as your symptoms started to show – in the region of taking around 8000mg a day – could reduce the severity of your cold and make it go away faster.

‘Vitamin C is a potent antioxidant that can improve the functioning of immune cells, helping with both prevention and fighting off infections,’ says Isom. ‘Supplementation can decrease the duration of cold by 1-1.5 days’.

The best form of vitamin C to supplement with is magnesium ascorbate. Isom suggests. This is vitamin C buffered with magnesium, which makes it less acidic.

‘Dosage-wise, research suggests that doses of around 1000mg can be beneficial for supporting the immune system. However this can be increased during periods of ill health [see above].’

Cold prevention remedy #6: Garlic

Garlic is a natural anti-microbial (antibacterial and antifungal) and anti-inflammatory compound, says Isom.

‘Various garlic preparations have been shown to exhibit antibacterial activity against parasitic bacteria such as Escherichia, Salmonella, Staphylococcus, and Clostridium to name a few,’ she says. But they’re all gut bugs. ‘It means garlic can help to support the immune system by supporting the microbial balance of the gut’.

In fact, majority of the research on garlic and the immune system relates to its antibacterial properties, Isom points out.

‘There is very limited research that exists on the use of garlic as an antiviral,’ Isom asserts. ‘Therefore, the use of garlic for the direct prevention of a common cold, which is viral, is questionable.

‘However, some studies are indicating that garlic can increase the activity of natural killer cells, which are immune cells that are involved in containing and controlling viral infections. So, consuming garlic could be beneficial, but perhaps not the first point of call for cold prevention due to the lack of research’.

Cold prevention remedy #7: Probiotics

Your gut is now referred to by experts as the body’s ‘second immune system.’

That’s because the gut immune system contains 70–80 per cent of the body’s immune cells and can be the main gateway for infections, Isom explains.

‘An imbalance in our gut microflora has been linked to an increased presence of infections, as well as autoimmune conditions,’ she says.

‘Supporting gut health with live bacteria, or probiotics can be really beneficial for supporting the immune system’.

In another Cochrane Systematic Review published in 2011, authors looked at 14 randomised clinical trials and concluded that using probiotics were better than placebo at helping reduce the incidence of upper respiratory tract infections and reduced the need for antibiotics.

Our modern highly processed diets and stressed out lifestyles can negatively impact our gut bacteria, especially over the winter period and with Christmas indulgences, like alcohol and mince pies.

So supporting our gut microbiome is especially important at this time of the year, Isom asserts.

‘This can be done via supplementation, or the consumption of fermented foods such as kefir, sauerkraut, kimchee and kombucha’.

Cold prevention remedy #8: Beta-glucans

Beta glucans are a type of carbohydrate present in the cell walls of certain fungi such as mushrooms as well as in the cell walls of foods such as whole oats.

‘These are capable of stimulating our immune system and can help to reduce the occurrence, symptoms, and duration of upper respiratory tract infections and colds, so increasing our intake of them through food and supplements can be helpful at this time of the year,’ advises Isom.

In fact, in a 2013 double blind, placebo-controlled clinical study published in the Journal of European Nutrition found that supplementation with beta glucans (those in the study were given Brewer’s Yeast which is a source of this) reduced the number of symptomatic cold and flu infections in subjects by 25 per cent.

Other rich sources of beta glucans include barley, wheat, rye and seaweed.

BioCare’s Immune Intensive Preparation contains vitamins high doses of beta glucans along with, vitamins C (magnesium ascorbate) and D (vitamin D3) from £16.45 for a 7 day pack

Cold prevention remedy #9: Wash your hands all the time!

According to the Global Handwashing Partnership, handwashing can help prevent up to 21 per cent of colds and upper respiratory tract infections – quite good going for something that’s totally free.

Here’s how it works. Germs live on all of our hands, whether we like it or not. According to the Centre For Disease Control in the US, ‘people touch their face, nose, mouth and eyes without even realizing it and germs get into the body through the these areas and make us sick.

Say you’re on a packed Tube and one person sneezes and that person has a cold. Those germ particles end up literally all over that tube so the next thing you touch, for example the newspaper you grab from behind the offending sneezer, could well be infected with those germs.

If you don’t wash your hands when you get off that infected Tube and inevitably touch your eyes, nose or mouth, presto, then you’re infected.

This is also why the person sneezes a should be trapping their sneezes – along with the coughs and yawns – in a tissue they then dispose of.

It goes without saying, but we’ll say it anyway – use three pumps of soap and wash with warm water, creating good lather! Check out the NHS video here.

Cold prevention remedy #10: Take zinc

Zinc is well known as a cold remedy and in 2014, a report published in the Canadian Medical Association Journal looking at the evidence for common cold remedies concluded that taking 10-15mg of zinc sulfate was likely to be beneficial at preventing the common cold, especially in kids.

In one of the studies in the report, the proportion of children with no colds during the study period was 33 per cent in the zinc group versus 14 per cent in the control group.

According to the NHS the daily recommended amount of zinc for women is 7mg, and 9.5mg for men (ages 19-64). For kids, it’s a bit different. 1-3 year olds should consume 5mg, 4-6 years olds should have 6.5mg, 7-10 year olds should have 7mg and 11-14 years olds should have 9mg.

Zinc supplements are best taken an hour before a meal, or 2-3 hours after a meal.

‘Although the evidence for cold prevention with zinc comes from studies involving only children, there is no biological reason why zinc would work only in children and not adults,’ the authors concluded.