The clocks have changed, the evenings are shorter, it’s certainly chillier and it’s fair to say that winter is most definitely coming…
This is a busy and exciting time of year with much to look forward to: holidays, time with family and friends and plenty of reasons to be merry. However, the changing season does bring challenges to our bodies and it is important that we consider our health at this time of the year. The colder weather, the greater the prevalence of common illnesses and the reduced exposure to sunlight can all potentially lead to us feeling unwell or unhappy.
Despite this, there are many ways in which we can make changes to our lifestyle to stay not only healthy but also happy over the winter period. There are also lots of “myths” around how to stay well over the winter months.
Washing your Hands
During the winter months the risk of catching flu, norovirus (also known as the winter vomiting bug), and other infections, is much greater. During this time of the year we spend more time indoors with the windows closed and the heating on, which produces the perfect environment for bugs to thrive. The workplace is also the ideal “exchange zone” for these bugs due to indirect contact with door handles, keyboards and mouses as well as the use of shared (sometimes poorly cleaned) kitchen areas.
Here are some lovely facts about bugs in the workplace:
- The typical office worker’s hands come into contact with 10 million bacteria per day (1)
- Surveys reveal 62% of men and 40% of women don’t wash their hands (2)
- Computer mice have three times more bacteria and keyboards more than 5 times more bacteria than the average toilet seat (1)
- 91% of smartphones analysed showed bacterial contamination (3)
- 40% of European workers admit to using their phones on the toilet (4)
With an increasing proportion of the work force “hot desking”, many eating their lunch at their desk, and many on their mobile phones all the time (even when on the toilet!), it is no wonder that the workplace poses such a threat to our health and that absence through illness costs the UK employer around £29 billion every year (4).
Washing hands with soap and water is optimal but using alcohol gel with an alcohol level of at least 60% is effective at killing the majority of the bugs lurking on your hands. It is worth noting these gels will not target some stomach bugs like the notorious Clostridium difficile and norovirus. A study has also revealed that damp hands spread 1000 times more bacteria than dry hands (5). With frequent hand washing we can decrease the bacteria present on our hands by 80% and reduce risk of subsequent illness by up to 50% (1).
Take Home Tip
Use soap where possible and take time over hand washing: rub soap all over your hands, front and back, including fingers and thumbs, rinse thoroughly and finally dry your hands properly before finishing the routine. This will reduce your risk of contracting an infectious disease and reduce risk of passing it to others.
Over the winter months we can often find it easier to eat convenience food and ready meals. The feeling of having “carb cravings” is common and is likely due to tiredness and low mood, leading to a “need” for that quick release of the feel-good hormones that can be produced when we consume these foods.
Ensuring that our food intake involves many different types of vegetables and fruits with a variety of colours, a good amount of fibre, some good sources of fats and trying to eat home cooked food wherever possible will go a long way to ensure our bodies have the right resources to fight off infections and help us feel energised and healthy. It is especially important to get adequate vitamin C, vitamin A and vitamin D as we know they play a key role in immune defence and protection against infection.
The issue around supplementation of vitamin C has been the subject of much debate over the years with many thinking high levels of vitamin C would fight off infection given its role in immune function. It is worth noting that you can get the required intake of vitamin C from your diet as there are a wide variety of easily accessible fruits and vegetables that contain a high level of vitamin C including broccoli, oranges, strawberries, blackcurrants, broccoli, brussels sprouts and potatoes. It is best to steam vegetables to ensure they maintain their high levels of vitamin C as boiling and even microwaving results in a reduction in the vitamin C content of your food. (6)
A very large Cochrane review showed that Vitamin C supplementation did not reduce the number of cases of the common cold when they looked at the different studies in which patients all had doses of 200mg or more (7). Even in studies where doses were 1-3g of vitamin C were used, no effect was seen. Interestingly the average duration of the cold was reduced by 8% in adults and 14% in children in these trials but it is worth noting reductions were not seen in all studies. Some of the studies specifically looked at subjects under severe short term physical stress such as marathon runners, skiers and soldiers. In these cases, taking between 0.25-1.0 g/day halved the incidence of common colds. When longer term stress was studied at a similar dose however, no benefit was seen. This could suggest a role of vitamin C in situations of acute demand or stress but there is little evidence for long term use. In studies in which vitamins were started at the onset of cold symptoms, there was no difference in duration or severity of a cold.
Although it has been previously claimed that vitamin C in tablet form is not as well used by the body as vitamin C from foods, published evidence doesn’t seem to suggest this. The bioavailability of vitamin C in natural and synthetic form appears to be very similar, with any small differences are thought to have minimal actual impact on health. However it is important to note that foods that contain vitamin C, unlike supplements, also have many other nutritional benefits such as containing other vitamins and minerals as well as being good sources of fibre and phytochemicals.
Take home tip:
So, vitamin C tablets may be worth using in doses > 200 mg in order to slightly reduce the duration of the common cold, but unfortunately in order to get the potential benefits you would need to be taking it all winter and the reduction in illness is quite minimal. If you undergo increased physical stress, such as running a marathon or high level of training, then it may be worth supplementing as this did seem to reduce incidence of the common cold (7). However, as always, aim for a food first approach and supplement as necessary.
Zinc is another supplement that is thought to play a role in immune function and has also been the subject of a Cochrane review looking at its effects in reducing the incidence, severity and duration of common cold (8). It was found that zinc given within 24 hours of the onset of cold symptoms reduces the duration of common cold symptoms in healthy people by up to 2 days (or by about 1/3rd of the illness), but there was some variation in the results. Doses of >75mg/day in lozenge form were used in many of the studies that showed a benefit but it is important to be aware that side effects such as nausea and a bad taste can occur. There doesn’t seem to be any benefit in continuing the zinc once the infection has cleared, so it is best to stop using it: excess zinc can lead to copper deficiency and this can cause anaemia, low levels of white blood cells and even memory issues. (9)
It has long been believed that garlic has antimicrobial and antiviral properties that can help common cold symptoms. Research in this area is limited with only 1 study meeting inclusion criteria for a Cochrane review (10). This study showed surprisingly positive results. 146 participants took part with one group assigned a garlic supplement and one a placebo for 12 weeks. The placebo group reported 65 cases of common cold with the garlic supplement group having only 24, which sounds impressive but this is only one small trial. The length of recovery from illness was similar in both groups. So should we just put garlic in everything now as we have a good excuse for having smelly breath? Obviously there isn’t nearly enough evidence for this just yet, but adding some to your food as part of a healthy diet could be worth considering. Plus there are plenty of other benefits to eating garlic!
Vitamin D is a fat soluble vitamin that is essential for our health and wellbeing. It is important for bone health due to its role in calcium metabolism but is also a huge variety of other roles including cell growth, neuromuscular and immune function and fighting inflammation (11). The main way in which we can make vitamin D is through our skin synthesising it when exposed to the sunlight. Most foods contain very little vitamin D but there are some which contain small amounts, including oily fish (like sardines, pilchards, herring, trouts, tuna, salmon and mackerel) as well as egg yolk, red meat and liver.
The changing wavelength of light throughout the year means that in the summer months just 20-30 minutes of sunlight on the face and forearms around 2-3 times a week is enough to make plentiful vitamin D. However, between October and April much of the UK will not have enough UVB rays in sunlight to make enough vitamin D in the skin.
Recommendations from the Department of Health advise breastfed babies and babies up to one year of age should have daily supplementation of 8.5-10mcg of vitamin D each day and children from the age of one year and adults should receive 10mcg of vitamin D each day during the months of October to April (11). It is worth noting that formula fed babies shouldn’t be given vitamin D as formula milk is fortified with vitamin D. Those especially at risk of vitamin D deficiency, such as those who are housebound, those who live in care homes, those who cover up most of their skin when outside and those with darker skin tones may benefit from having a supplement all year round.
Interestingly a recent systematic review and meta-analysis looked at 81 randomised controlled trials which included over 53,000 participants looking at vitamin D supplementation and musculoskeletal health (12). They found that supplementation does not reduce fractures or falls and has no significant effect on bone mineral density. They concluded that there is no requirement to supplement with vitamin D to support musculoskeletal health. However before we decide to disregard current advice, this data is based just on adults, so does not extend to children, and only a small proportion had deficient levels, whereas it is thought that 20% of the UK population is thought to be deficient in vitamin D (13). Furthermore, we can’t forget that vitamin D has multiple roles in the body, in addition to supporting bone health. There is research that supports it use for improved immune function (14) improved mood (15) and deficiency has also been shown to correlate with cardiovascular disease, autoimmune diseases and some cancers (16). So despite this new research, the current public health advice still stands.
While we touch on this important subject of immunity it is important to address the key player of sleep in helping fight off infection. There is lots of research that shows that sleep deprivation can lead to impairment with learning, memory processing, cellular repair and brain development as well as increasing risk of depression, obesity, high blood pressure and unhealthy eating habits.
It also has massive impact on our immune function. Poor sleep over a long period of time can lead to immunodeficiency (a dampened immune response) which can reduce the effects of vaccines (including the flu vaccine) and can also lead to an increased risk of catching the common cold (17). The impact of sleep on the immune system is very complex. Put simply going to bed earlier promotes the early initiation of immune response and eventually supports long lasting immunity. Prolonged poor sleep and the accompanying stress response can lead to a proinflammatory response and low grade inflammation, which can contribute to a weakened ability to fight off infectious illnesses.
It is well known that many more people feel low or down over the winter period, which can sometimes be due to Seasonal Affective Disorder (SAD). SAD is a type of depression that comes and goes in a seasonal pattern which is also known as “winter depression” or the winter blues (18). Those who suffer from this can have a range of symptoms from persistent low mood, loss of pleasure in normal everyday activities, irritability, feeling of despair, feeling lethargic, sleeping for longer and often craving carbohydrate and weight gain all associated with the winter months.
The cause of “SAD” is not fully understood however one of the main theories is related to lack of sunlight during the winter months. There is lots of evidence showing that light and darkness has an impact on our mood and behaviour due to many complex interactions in our bodies.
- Melatonin, the “sleep hormone” – Sunlight stimulates cells in our eyes to produce a chemical called melanopsin. Melanopsin affects the hypothalamus, an area of the brain in charge of homeostasis: causing it to suppress the release of melatonin from another area of the brain called the pineal gland. When there is less sunlight in winter months this pathway is not stimulated and therefore sleep-inducing melatonin is produced in greater quantities.
- Serotonin, the “happy hormone” – Lack of serotonin is also seen in winter months in those with SAD, thought to be due to reduced sunlight exposure. Serotonin is a very important neurotransmitter thought to contribute to feelings of wellbeing and happiness.
- Circadian rhythm, our internal “body clock” – Our bodies have an inbuilt timer which governs many processes in our bodies. Although this is internally regulated, some external signals can have an impact on this system. Reduced sunlight during the winter months can disrupt our body clocks, leading to feelings of tiredness and low mood.
There are lots of lifestyle changes which can greatly reduce your risk of feeling low or tired and reduce your risk of experiencing SAD. Ensuring you get as much natural sunlight as possible can make a big difference to prevent or reduce the processes thought to lead to the disorder as detailed above. So spending time during the day to get out and about, even if just for a brief walk, can make a big impact. Exercising and ensuring you have practices to reduce stress such as meditation or taking time to be mindful has also been shown to be beneficial in reducing symptoms of low mood and tiredness.
There has been a lot of research looking at using light treatment to help with feelings of low mood associated with SAD. There are many different versions of this including dawn wake simulators. which are lights programmed to lower intensity in the evening and gradually increase light in the morning, and also light therapy boxes which can mimic sunlight. Both of these have been shown in the research to have significant effect at reducing symptoms of SAD when the dose is around 2500 lux for 2 hours a day or 10,000 lux for 30 minutes a day (19). Studies have even shown light therapy can be as effective as using antidepressant medication in the management of SAD (20). This does not mean you have to buy an artificial light in order to avoid SAD as lifestyle changes can make a big difference and reduce your risk significantly, but some may find an artificial light helps.
Many people tend to feel a little bit more down over the winter months without having a diagnosis of depression or SAD. One of the biggest things we can do to enhance our mood is to keep active. Exercise plays a large part in our mood and engaging in just 150 minutes of moderate intensity physical activity (i.e. hard enough that you are a little out of breath but can still hold a conversation) every week while reducing our time sat down has the potential to reduce our risk of anxiety and depression by up to 30% (21). Find something you enjoy and can keep consistent with or try a new challenge to excite you and spur you on to keep your activity up and look after your mood.
You don’t need supplements to be healthy over winter to stay healthy, with the exception of vitamin D which is certainly worth considering. The best things you can do for your health over the winter are to keep as active as possible, ensure a well balanced diet with plenty of plant based foods and home cooked meals, prioritise quality sleep and spend time outside in the light when you can. These things will all contribute significantly to you being healthier and happier over the winter period.
(1) Charles Gerber, Germs in the Workplace Study, University of Arizona 2004.
(2) Initial Hygiene Survey 100,000 office workers across Europe – https://www.initial.co.uk/washroom-news/2015/initial-hygiene-connect.html
(3) Bhoonderowa A, Gookool S and Biranjia SD. The Importance of Mobile Phones in the Possible Transmission of Bacterial Infections in the Community. J Community Health 2014 39(5):965-967
(4) Wash your hands of the bugs this winter. Dr Peter Barratt, Initial Washroom Hygiene
(5) Patrick, D.R., Findon, G. & Miller, T.E. (1997). Residual moisture determines the level of touch-contact associated bacterial transfer following hand washing. Epidemiology & Infection, 119, (3), 319-325.
(6) Zeng C (2013) Effects of different cooking methods on the vitamin C content of selected vegetables. Nutrition and Food Science Vol 43 Iss 5:438-443
(7) Hemila H, Chalker E. Vitamin C for preventing and treating the common cold Cochrane Database Syst Rev. Jan 31(1)
(8) Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev 2013 Jun 18(6)
(9) Willis MS, Monaghan SA, Miller ML, McKenna RW, Perkins WD, Levinson BS, Bhushan V and Kroft SH. Zinc-Induced Copper Deficiency: A report of Three Cases Initially Recognized on Bone Marrow Examination. Am J Clin Pathol 2005;123:125-131
(10) Lissiman E, Bhasale AL, Cohen M. Garlic for the common cold. Cochrane Database Syst Rev 2014 Nov 11 (11):CD006206
(11) NHS Choices – Vitamin D – https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
(12) Bollard MJ, Grey A and Avenell A. Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. Lancet Diabetes Endocrinol 2018;6:847-58
(13) Nutrition.org – New reports – new advice on vitamin D – https://www.nutrition.org.uk/nutritioninthenews/new-reports/983-newvitamind.html
(14) Prietl B, Treiber G, Pieber TR and Amrein K. Vitamin D and immune function. Nutrients 2013 Jul 5;5(7):2502-21
(15) Shaffer JA, Edmondson D, Wasson LT, Falzon L, Homma K, Ezeokoli N, Li P and Davidson KW. Vitamin D Supplementation for Depressive Symptoms: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Psychosom Med 2014 April; 76(3):190-196
(16) Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers and cardiovascular disease. Am J Clin Nutr. 2004 Dec;80(6):1678S-88S
(17) Besedovsky L, Lange T and Born J. Sleep and Immune Function. Eur J Physiol 2012 463:121-137
(18) Patient UK – Seasonal Affective Disorder – https://patient.info/doctor/seasonal-affective-disorder-pro
(19) Golden et al 2005. The Efficacy of Light Therapy in the Treatment of Mood Disorders: A Review and Meta-Analysis of the Evidence. AM J Psychiatry 162:656-662
(20) Lam et al 2006. The Can-SAD Study: A Randomised Controlled Trial of the Effectiveness of Light Therapy and Fluoxetine in Patients with Winter Seasonal Affective Disorder. Am J Psychiatry 2006; 163:805-812
(21) NHS Choices – Live Well – Benefits of Exercise – https://www.nhs.uk/live-well/exercise/exercise-health-benefits/