It’s safe to say that 2020 hasn’t been as anyone expected. Along with the ever-changing rules on lockdowns and PPE, there have several articles claiming that certain foods can boost our immune system and ultimately prevent the complications of COVID-19. Here, regular NHD contributor and guest blogger Rebecca Gasche takes a look at the facts...

Research for this blog post began with a quick Google, to see what information is readily available to the general public. One of the first articles that popped up listed the following foods as ‘immune boosting’:

• Elderberries
• Oysters
• Watermelon
• Mushrooms (specifically button mushrooms, obviously)
• Acai berries
• Wheat germ
• Low-fat yoghurt (but no full-fat, oh no)
• Spinach
• Tea, famously green tea
• Sweet potatoes
• Broccoli
• Garlic
• Miso soup
• Chicken soup
• Pomegranate juice
• Ginger

The article also discusses how reducing stress, owning pets, having a positive attitude and even a healthy sex life can all boost your immunity!¹

Another food that frequently makes an appearance in all-things wellness is celery, in particular celery juice, which boasts magical powers such as:

• containing mineral salts that boost your immune system;
• reducing symptoms of chronic joint pain due to its anti-inflammatory properties;
• increasing the production of liver enzymes and therefore improving liver function;
• fighting infections due to antimicrobial properties;
• reducing uric acid to help with bladder infections;
• the ability to reverse digestive issues such as bloating, diarrhoea and constipation;
• increasing gastric mucus, which helps people with gastric ulcers.²

Amazing, right? It seems too good to be true!

That’s because, it is.

THE FACTS

Unfortunately for the wellness trend, there are no specific foods, juice cleanses or exercises that can ‘boost’ our immune system. With regards to celery juice, yes it contains small (and I mean small) amounts of vitamins/minerals and will hydrate you (as any other liquid would), but that’s about it. There is no evidence to support its pH-changing, hormone-balancing, gut-healing claims. The European Food Safety Authority (EFSA) has also not authorised any claim for a food or food component in the UK to be labelled as protecting against infection.³

Rather than listing individual foods that claim to have magical immune boosting powers, focusing on having a well-balanced diet will support your normal immune system function. So, in a way, the foods in the above list are certainly not going to cause any harm if included in the diet. However, they sit within an abundance of different fruit and vegetables that will do the same job in providing the essential vitamins and minerals that are needed.

Components of the diet that have been known to support our already functioning immune system include:

• Vitamin C
• Vitamin A
• Vitamin D
• Zinc
• Copper
• Folate
• Iron
• Selenium
• Vitamin B6
• Vitamin B12⁴

The daily recommended amounts of these can usually be found in diets rich in different varieties of fruit and vegetables, meat or plant proteins and wholegrains.

Rather than consuming these nutrients in the hope to boost the immune system, we should be consuming them to prevent deficiencies, which may weaken the immune system.

SO WHAT ABOUT CORONAVIRUS?

The British Dietetic Association (BDA) released a statement earlier this year which included the quote: ‘People sharing unevidenced nutrition solutions to COVID-19 may increase the risk that someone doesn’t take proper hygiene and social distancing precautions. It’s vital that we stop spreading this misinformation.’ Andy Burman BDA CEO⁴

An article published in the Irish Medical Journal earlier this year suggested that supplementing vulnerable patients with 20-50mcg vit D/day could enhance resistance to COVID-19⁵ and guidelines produced by NICE recommend that throughout the COVID-19 pandemic, the UK population considers taking a 10mcg daily vitamin D supplement.⁶ However, the NICE guidance also states that there is no strong evidence to suggest vitamin D can prevent or treat covid-19. The recommendation of 10mcg/day is less so because of the links with respiratory diseases as discussed in McCartney and Byrne’s article,⁵ but more so due to the population spending more time indoors due to shielding or self-isolating.Standard advice for vitamin D in the UK is to take 10mcg throughout winter months.⁷

The relationship between vitamin D and COVID has been affirmed in the recent report by Lanham-Newet al: ‘As a key micronutrient, vitamin D should be given particular focus — not as a ‘magic bullet’ to beat COVID-19, as the scientific evidence base is severely lacking at this time — but rather as part of a healthy lifestyle strategy to ensure that populations are nutritionally in the best possible place.’⁸

So, for COVID-19, reasons or not, take your supplements!

It remains that the most important measures to stay safe during the pandemic include maintaining strict hand hygiene and abiding by social distancing rules. Alongside this, while we can’t boost our immune system, we can help to support it by consuming a well-balanced diet and taking a 10mcg vitamin D supplement.

Rebecca Gasche
Clinical Lead Dietitian
Countess of Chester Hospital NHS Trust 

Rebecca has a keen interest and specialises in gastroenterology
dietetics. She is currently working as Dietetic Lead for the
gastroenterology service within West Cheshire.

References

1. 16 Foods that Boost and Improve your immune system. On Health. Retrieved from https://www.onhealth.com/content/1/immune_system_boost
2. Here’s Why Celery Juice is the Biggest Trend in Health and Wellness Right Now.Forbes. Retrieved from https://www.forbes.com/sites/jennifercohen/2019/09/06/everything-you-need-to-know-about-celery-juice/#46dc1b646069
3. EU Register of nutrition and health claims made on foods. https://ec.europa.eu/food/safety/labelling_nutrition/claims/register/public/?event=register.home
4. Covid-19 / Coronavirus – Advice for the General Public. British Dietetic Association. Retrieved from https://www.bda.uk.com/resource/there-is-no-diet-to-prevent-coronavirus.html
5. McCartney D, Byrne D. Optimisation of Vitamin D Status for Enhanced Immuno-protection Against Covid-19. April 2020. Irish medical journal 113(4):58
6. National Institute for Health and Care Excellence. COVID-19 rapid evidence summary: vitamin D for COVID-19. Evidence summary [ES28]. Retrieved from  https://www.nice.org.uk/advice/es28/chapter/Advisory-statement-on-likely-place-in-therapy
7. Vitamin D. National Health Service. Retrieved from https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
8. Susan A Lanham-New SA et al (2020).Vitamin D and SARS-CoV-2 virus/COVID-19 disease. BMJ Nutrition Prevention and Health April 2020. https://nutrition.bmj.com/content/3/1/106