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With the exciting development of effective vaccines against COVID-19, it's important to make sure your body is in the best state possible to receive the jab. Following a healthy diet and lifestyle, and correcting vitamin and mineral deficiencies, can help to maximise your level of protective antibodies and cell-mediated responses produced by vaccination.
Vaccines provide a small, non-infectious part of the coronavirus responsible for COVID-19 so your immune system recognises it as foreign and mounts a defence.
Memory cells that remember this viral component then patrol your body in a resting state. These memory cells – T and B lymphocytes – have a long life (typically several decades) and remain ready to attack the virus if it is encountered in the future.
How long the new immunisations will protect against COVID-19 is not yet certain, but there are steps you can take to help optimise your health to help achieve a good outcome.
With most vaccinations, such as those against influenza, people over the age of 65 tend to produce a reduced antibody response compared with younger adults due to an ageing process known as immunosenescence. This effect is even more pronounced in those who are obese.1
However, encouraging results from preliminary trials involving the Oxford coronavirus vaccine suggest that healthy people in their 60s and 70s develop as strong an immune response as that seen in younger age groups. Almost all developed neutralising levels of antibodies within 14 days after their second booster dose, as well as good activation of T-lymphocytes – the immune cells that coordinate attacks against infection.2
However, these trials did not include people who had severe or poorly-controlled health conditions, or those who were frail, so it’s not yet known how these more vulnerable groups will respond. What we do know is that, in other situations, certain diet and lifestyle changes can help to give vaccines the best chance of success.
One theory to explain immunosenescence is that, as people get older, they develop more vitamin and mineral deficiencies and higher levels of inflammation. If this is the case, then taking a multivitamin to replenish deficiencies may help the immune system work at optimal efficiency.
Almost all the essential micronutrients play a role in our defences, and especially vitamins A, B6, B9 (folic acid), B12, C and D, plus the minerals copper, iron, selenium and zinc. Even a relatively minor lack of these can reduce your response to infections and immunisations.
Selenium is particularly important for a number of reasons:
Average UK intakes of selenium have fallen since 1975 from 60mcg per day to 34mcg per day as we now obtain our wheat from Europe (where soil selenium levels are low) rather than Canada and the US where selenium levels are relatively high.5
National Diet and Nutrition Surveys now show that one in two females and one in four males have total selenium intakes beneath the amount (the Lower Reference Nutrient Intake of 40mcg per day) needed to prevent deficiency symptoms.6
The richest dietary source of selenium is Brazil nuts and small amounts are also found in fish, poultry, meats, wholegrains, mushrooms, onions, garlic, broccoli and cabbage. However, it is difficult to obtain the EU recommended intake of 55mcg per day without taking a multivitamin that includes selenium.
Among the other important micronutrients for immunity is vitamin C, which suppresses the activation of viral genes so viruses are less able to replicate. As a powerful antioxidant, it also helps to resolve the inflammation associated with viral infections to improve symptoms and hasten healing.7
Vitamin D is important for regulating the activity of immune cells, including the memory B and T lymphocytes which maintain our protection.8 Low levels of vitamin D may reduce the response to vaccination and in those who are deficient, taking a supplement improved the response to influenza vaccination by promoting higher levels of a regulating chemical called transforming growth factor beta (TGFβ).9
A recent study involving people aged 55 and over found that those who took a daily multivitamin and mineral supplement for 12 weeks (which included vitamins A, D, E, B6, B12, folate and a high dose of vitamin C (1,000mg) plus iron, copper, zinc and selenium) were significantly better at fighting off infections than those taking a placebo.
The number of sick days in those taking the multivitamin was less than three, compared to more than six for those taking placebo.10
When it comes to vaccination, a supplement also seems to improve immune responses. When healthy older adults aged 65 and over were given a complete nutritional supplement, or placebo, for seven months, there was a significant increase in the level of antibodies they produced against one particular influenza strain.11 However, larger trials are needed to confirm this.
Eating a healthy, wholefood diet supplying at least five and preferably more servings of fruit, vegetables and fresh juices per day will provide good amounts of vitamins, minerals, antioxidants and other beneficial plant substances. Eat them raw, where possible, or only lightly steamed to preserve their nutrient content.
Choosing to eat organically helps to maximise intakes of trace elements such as selenium, as well as reducing exposure to agricultural chemicals whose effects on immunity are not yet fully understood.
Eat oily fish (such as salmon, mackerel, herring or sardines) at least twice a week, as their omega 3 essential fatty acids increase the fluidity and responsiveness of immune cell membranes.12 Fish are also a source of vitamin D, and those with good vitamin D levels are less likely to experience a cold than those with low levels.13
Eat live bio yoghurts containing Lactobacilli, which prime the immune system by activating T-lymphocytes,14 and encourage production of anti-bacterial antibodies and the secretion of the natural, anti-viral substance interferon. A probiotic fermented dairy drink was found to improve antibody responses to flu vaccination in the elderly.15
Avoid excess stress, which interferes with immune function in a way that is not fully understood. Stress has been shown to reduce the protective effects of influenza vaccination – the more stressed you are, the fewer antibodies you produce following immunisation.16
Take regular exercise, which enhances immunity through an unknown mechanism, but one that is probably linked with burning off the effects of stress.17
Get enough sleep, as this is when your body is actively regenerating vital proteins involved in healing and fighting disease. Sleep is also important as it is during this time that our immune cells (especially T-lymphocytes) return to our lymph nodes for priming and forming immune memories.18
Dr Sarah Brewer is Healthspan's Medical Director and holds degrees in Natural Sciences, Surgery and Medicine from the University of Cambridge. Having worked as a GP and hospital doctor, Dr Sarah now holds an MSc in Nutritional Medicine from the University of Surrey and specialises in nutrition. She is also an award-winning writer and author.
Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.
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2Ramasamy, M.N. et al. (2020). Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial. The Lancet
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