Vitamins to stay healthy during winter

Chilly weather and shorter daylight hours can leave us feeling groggy, low in mood and may even disrupt our sleep-wake cycle. The elements can dry out the skin and cause eczema, arthritis, and asthma to flare up. Though important, keeping warm, fit, and active is just one side of the coin. Something just as crucial—but sometimes neglected—is what we put into our bodies.  

We look at some key vitamins and minerals and how they are particularly beneficial in winter. Most are essential, meaning the body can’t make them, and they must come from our diet. It’s useful to know what foods contain them to make sure you’re meeting your recommended daily intake, and if not, whether to consider a supplement. 

Vitamin D 

Vitamin D helps us absorb phosphate and calcium from our diet, both essential for healthy bones, teeth, and muscles.  

Our main source of vitamin D is from sunlight, however, as days shorten (particularly October through to March), we can become deficient. We can get small amounts from our diet, but often not enough, which is why a daily 10µg supplement is recommended over the autumn and winter months [1]. For some people, it is recommended that a supplement is taken all year round. 

People recommended to take a vitamin D supplement: 

• People with dark skin (for example, if you are African, Afro-Caribbean, or South Asian) 
• Babies up to the age of one if they are formula-fed with less than 500ml a day or breast-fed 
• Children aged one to four 
• People who spend limited time outdoors or cover most of their skin while outdoors [2]

A deficiency of the sunshine vitamin can lead to non-specific symptoms, making it difficult to spot.  

Symptoms include:  

• Excessive fatigue 
• Mood changes 
• Hair loss 
• Joint pain 
• Muscle aches 

Vitamin D also plays a role in immunity and can protect against respiratory infections [3], important for the cold and flu season. You can check your levels with our Vitamin D (25 OH) Blood Test.

Sources of vitamin D: 

• Oily fish 
• Fortified cereals 
• Red meat 
• Egg yolks 

Is there a link between vitamin D and COVID-19? 

Of recent interest is the potential benefits of vitamin D in the treatment of COVID-19. At the time of writing, based on the available studies, there is not currently enough evidence to conclude that vitamin D prevents death for those affected with COVID-19.  

Vitamin D may reduce the need for a ventilator, compared with placebo. But due to the limited number of studies and inconsistencies in measuring treatment outcomes, further research and clarification are required. Randomised control trials are currently underway [4]. 

Vitamin C 

Vitamin C is another multi-functional micronutrient that supports and strengthens our immune system. Its potent antioxidant properties enhance the function of white blood cells by assisting with migration to where they need to go - namely at the site of infection. This then enhances phagocytosis, the process of engulfing and breaking down bacteria and other foreign bodies, ultimately killing microbes. It also helps the controlled death and clearance of obsolete cells, which can contribute to tissue damage [5]. 

It is perhaps no surprise that a vitamin C deficiency can leave your immune system vulnerable to infection. What’s more, an infection can significantly impact levels of vitamin C due to high levels of inflammation and metabolic activity [5]. Adults need about 40mg of vitamin C a day as the body can’t store it. You can achieve this through diet alone, or if you’re finding this difficult, supplements (no more than 1000mg) are an easy and effective way to boost your levels and keep illness at bay. 

Sources of vitamin C: 

• Citrus fruits 
• Tomatoes 
• Avocado 
• Peppers 
• Strawberries and blackcurrants 

Vitamin E 

Vitamin E is an antioxidant, combatting the effects of free radicals produced by the breakdown of food and toxins. It is a key player in regulating the body’s immune responses to infection, helping us to fight off those seasonal coughs and colds [6]. 

Unlike vitamin D, vitamin E deficiency is rare as you can generally get enough through the diet, but occasionally supplementation may be recommended. Vitamin E can also be found in moisturisers and other skincare products, where it nourishes the skin at the source, protecting it from damage and enabling healing [7], making it a good remedy for dry and flaky winter skin. 

Sources of vitamin E: 

• Wheatgerm 
• Vegetable oil and olive oil 
• Nuts and seeds 
• Avocado 
• Spinach and broccoli 

Iron 

Iron is a mineral essential for creating haemoglobin, the protein that carries oxygen to the tissues to release energy.  

Some winter complaints—tiredness, irritability, cold intolerance, and pale skin—may be attributable to an iron deficiency. It is perhaps more common than you think, affecting up to two billion people worldwide  and up to a quarter of women in the UK aged 19 to 64 [8, 9]. Women, vegetarians and vegans are among the people most at risk due to menstrual losses and a lack of iron intake respectively. 

Iron has many functions in the body, including physical and cognitive performance. It plays a vital part in thermoregulation - the ability to maintain a constant body temperature in response to cold stress. A lack of iron can also disturb the immune system, increasing the risk of illness and infection [10]. Therefore, checking your iron levels are sufficient this winter can help to keep you warm and well. 

Sources of iron: 

• Red meat 
• Liver (though avoid in pregnancy) 
• Beans and pulses
• Nuts 
• Green vegetables such as spinach, broccoli, and kale 

B vitamins 

The B vitamins are a family of vitamins, each with different functions. Broadly speaking, they are involved in the body’s metabolic activity (to release energy) and ensure the normal functioning of the nervous system. The vitamin B complex also supports the immune system and contributes to healthy skin, hair, and nails, particularly B2, B3, and B7. 

Vitamin B6 (pyridoxine), B9 (folic acid), and B12 (cyanocobalamin) —are crucial in producing healthy red blood cells. Therefore, as with iron, a deficit can cause anaemia and impact energy levels and mood.  

A lack of these B vitamins can also lead to depression [11], something not uncommon in winter, so check you’re not lacking in these super vitamins to stay energised and in good spirits. You can test levels easily with our at-home finger-prick testing kits. 

Sources of B vitamins: 

• Meat and liver 
• Fish 
• Eggs 
• Milk 
• Nuts 
• Legumes 

Zinc 

Zinc is an essential mineral for the normal functioning of many different systems in the body, including the reproductive, nervous, and immune systems. It ensures the healthy production and maturation of white blood cells, which are the guard cells in our bloodstream that fight off infection. Zinc is also critical for wound healing [12], making it one of the more important minerals for staying healthy this winter. 

Sources of zinc: 

• Meat 
• Cheese 
• Bread 
• Wheatgerm 
• Shellfish 

What’s the verdict on vitamins for winter? 

During the cold and flu season, vitamins and minerals form a fundamental part of our natural defences, keeping us well and energised. It is best to get your vitamin and mineral requirements through your diet. But, in some cases, a supplement may be an easier and more effective way to meet your recommended intake—just make sure you are not taking over the recommended dose.

Related tests 

• Vitamin D (25 OH) Blood Test – We all risk becoming deficient in vitamin D over winter. Check your levels with this simple finger-prick test. 
• Advanced Vitamin B12 Blood Test – A check that looks at 18 biomarkers including vitamins B9, B12, ferritin, and your red and white blood cells. This is a useful test to look for anaemia related to a deficiency of iron or B vitamins.  

References 

1. Public Health England. (2020) Statement from PHE and NICE on vitamin D supplementation during winter. Available at: https://www.gov.uk/government/publications/vitamin-d-supplementation-during-winter-phe-and-nice-statement/statement-from-phe-and-nice-on-vitamin-d-supplementation-during-winter (Accessed 21 September 2021) 
2. NHS. (2020) Vitamin D. Available at: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/ (Accessed 21 September 2021).  
3. Jolliffe D. A. et al. (2020) Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials. medRxiv [Preprint]. 2020 Nov 25:2020.07.14.20152728. doi: 10.1101/2020.07.14.20152728. Update in: Lancet Diabetes Endocrinol. 2021 Mar 30. 
4. Stroehlein JK et al. (2021) Vitamin D supplementation for the treatment of COVID-19: a living systematic review. Cochrane Database of Systematic Reviews 2021, Issue 5. Art. No.: CD015043. DOI: 10.1002/14651858.CD015043. 
5. Carr AC, Maggini S. (2017) Vitamin C and Immune Function. Nutrients. 3;9(11):1211. doi: 10.3390/nu9111211. PMID: 29099763; PMCID: PMC5707683. 
6. Lee, Ga Y. and Sung N. Han. (2018) The Role of Vitamin E in Immunity. Nutrients, 10, no. 11: 1614. https://doi.org/10.3390/nu10111614 
7. Santos J. S., Tavares G. D. and Barradas T. N. (2021). Vitamin E and Derivatives in Skin Health Promotion, Vitamin E in Health and Disease - Interactions, Diseases and Health Aspects, Prof. Pınar Erkekoglu and Dr. Júlia Scherer Santos, IntechOpen, DOI: 10.5772/intechopen.99466. Available from: https://www.intechopen.com/chapters/78135 
8. Miller J. L. (2013) Iron deficiency anemia: a common and curable disease. Cold Spring Harbor perspectives in medicine, 3(7), a011866. https://doi.org/10.1101/cshperspect.a011866 
9. National Diet and Nutrition Survey. (2020) National Diet and Nutrition Survey Rolling programme Years 9 to 11 (2016/2017 to 2018/2019). Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/943114/NDNS_UK_Y9-11_report.pdf (Accessed 22 September 2021). 
10. Zimmermann M. B., Hurrell R. F. (2007). Nutritional iron deficiency. Lancet. 370(9586):511-20. doi: 10.1016/S0140-6736(07)61235-5. PMID: 17693180. 
11. Mikkelsen K, Stojanovska L, Apostolopoulos V. (2016) The Effects of Vitamin B in Depression. Curr Med Chem. 23(38):4317-4337. doi: 10.2174/0929867323666160920110810. PMID: 27655070. 
12. Lin, P. H., Sermersheim, M., Li, H., Lee, P. and Steinberg, S. M., & Ma, J. (2017). Zinc in Wound Healing Modulation. Nutrients, 10(1), 16. https://doi.org/10.3390/nu10010016