HANDS. FACE. SUPPS

Supplements are booming in this Covid era, but can they really ‘boost’ your immunity?

While an as-yet unsolved global pandemic has been bad for business in most senses, the nutritional supplement market is booming, with sales of some vitamins and minerals up more than 100%. Before you stockpile supplements in the name of ‘boosting’ your immunity, read this

There are few health topics that feel trickier to navigate than immunity. With the exception, perhaps, of supplements. So you’d be forgiven for responding to a global pandemic by attempting to bolster the former with the latter. Last March, just as the UK was heading into the first nationwide lockdown, Britons spent £48.5 million on supplements, almost 20% more than the year before, according to data from Kantar. In the same month, sales of vitamin C alone increased by 110%, while Holland & Barrett revealed it sold 3,000% more capsules of vitamin D in May than it did in March. By the close of 2020, the UK supplement category was predicted to have grown 9.1% compared to 2019, to the tune of £494million*.

Attempting to supplement your immunity is a strategy that makes sense. After all, you’ve probably been bulk-buying OJ at the first sign of a sniffle for as long as you can remember. Throw in news reports about vitamin D’s link to reduced risk of respiratory infections, and it’s no wonder you’re snapping up supplements with the enthusiasm you once reserved for booking classes at F45. But here’s the rub: with only a handful of nutrients proven to influence immunity, there’s every chance your well-intentioned investment in ‘immunity-boosting’ vitamins and minerals is just money down the drain.

For starters, your immune system is more complex than the labyrinthine one-way system in your local boozer. It actually refers to two different bodily functions or processes, explains Dr Carrie Ruxton, a dietitian who works with the Health and Food Supplements Information Service (HSIS). ‘There’s the innate system, which is the immunity you’re born with, and then there’s the adaptive system that you develop as you get exposed to different infections, bacteria and viruses,’ she says.

She explains that the innate system largely consists of physical internal barriers and responses to pathogens (the organisms, such as a virus, that cause disease), and include the skin, the gut, stomach acid and sticky layers of mucus that line your mouth, nose and throat. Of these physical barriers, the gut is among the most vital, with the single layer of cells that line your small and large intestine making up

70% of your entire immune system. But when these barriers fail, and pathogens make it into your body, the adaptive immune system kicks in. White blood cells spot the pathogens moving through your body and fire off a response, including the release of cells and proteins – or antibodies – that can cause inflammation as they swell damaged tissues and fight off the disease. These same antibodies remain in the body and put you in a much better position to fight the same disease the next time around.

TRACK AND TRACE NUTRIENTS

All this means that your immune system evolves over time, with everything from your DNA to your diet contributing to its health. And it’s true that consuming the right micronutrients is an important part of the equation.

Azmina Govindji, a registered dietitian and spokeswoman for the British Dietetic Association, points to eight micronutrients for which the European Food Safety Authority (EFSA) has given the green light for claims around immunity; they are vitamin A, B (B6, B12 and folate) C and D, plus, zinc, copper, iron and selenium. So robust is the evidence for these eight, says Govindji, that companies manufacturing supplements for these nutrients can legally claim they each ‘contribute to the normal function of the immune system’. Take vitamin C: studies show it can both support and strengthen the physical barriers that your innate immune system is made up of, as well as boosting the ability of white blood cells to fend off infections in the body. Meanwhile, a 2018 paper published in the Journal Of Clinical Medicine described vitamin A as being ‘critical’ in keeping your innate immune system’s physical barriers – such as the lining of mucus in your stomach – healthy. As for B vitamins, studies show a lack of B6 and B12 can restrict the supply of antibodies vital for your adaptive immune system. Fail to get enough of any of these great eight and your immunity can be compromised.

‘We know that if you become deficient in the essential vitamins and minerals then you can get diseases of deficiency, and that these can impair your ability to fight infections,’ explains Dr Jenna Macciochi, an immunologist and author of Immunity: The Science Of Staying Well. A deficiency might leave you more susceptible to infection in the first place, or leave you feeling ill for longer.

PLATE EXPECTATIONS

It makes for a compelling case for supplementing your diet with these micronutrients. And yet, all the experts WH spoke to for this piece agreed that, in most instances, you can get the amounts you need of these vitamins and minerals from whole foods, as opposed to supplements. Forget the OJ, a medium-sized pepper provides more vitamin C (up to 152mg). Take more than the 180mg that studies suggest is the upper limit and, since it’s a water-soluble vitamin, you’ll just wee out any excess. Meanwhile, a carrot will deliver the recommended 600mg daily dose of vitamin A; a small handful of Brazil nuts will provide your 60mg of selenium; and a decent helping of shellfish, like mussels, will be sufficient to meet your 7mg zinc target. The upshot? If you’re eating a healthy, balanced diet – lots of protein, fruit and veg and a variety of different fats – then you’ll be getting all the vital micronutrients you need to keep your immune system healthy anyway.

What’s more, there are other benefits to getting your nutrients from food, as opposed to a pill. ‘One of the biggest things that we’ve realised is supportive of the immune system is dietary fibre,’ adds Dr Macciochi.

‘It feeds your gut microbiota and, when you digest it, you produce a plethora of different metabolites [substances formed in the metabolism process] that help nurture your immune system.’ Polyphenols and phytochemicals – plant chemicals thought to support the function of the brain and digestive system and even protect against heart disease, type 2 diabetes and certain cancers – are other examples of nutrients that seem to decline in potency when popped in a pill. ‘Most studies indicate that they don’t work

If you’re eating a healthy, balanced diet then you’ll be getting the vital micronutrients

as well as when you consume them via a plant source,’ she continues. ‘It’s likely because, when eaten within the context of a meal, there are all the other fats and fibres present to help your body absorb the protective plant chemicals.’

SUPP-LY AND DEMAND

Then, of course, there’s vitamin D, one nutrient that you’ve probably seen plastered all over the news recently. When the media uncovered a study published in 2017 in The BMJ that linked vitamin D to a reduced risk of respiratory infections, it led to speculation that topping up your levels could help protect against Covid-19 – a claim the Science Advisory Committee on Nutrition says isn’t supported by enough evidence.

That doesn’t mean you shouldn’t keep your levels topped up though. Vitamin D is still important for overall immune health: in a review of the latest evidence published in the journal Nutrients in March, professor of nutritional immunology at the University of Southampton Philip Calder concluded that vitamin D ‘increases the killing capacity’ of certain types of white blood cells (making them more likely to vanquish incoming pathogens).

And, unlike some of the other essential micronutrients, it’s harder to come by in your diet. While it’s found in limited quantities in oily fish, eggs and fortified foods, it’s mainly absorbed via exposure to sunlight, and perpetual cloudy weather in the UK means around 20% of Britons could be deficient. During the first lockdown last year, Public Health England updated its advice to recommend that everyone take a daily supplement (10mcg) to top up their levels (previously this advice had only applied to those deemed high risk). Opt for D3, rather than D2, suggests Dr Ruxton, as it absorbs more easily, and consume with a meal to improve bioavailability (something that applies to all fat-soluble vitamins, i.e. A, D and E).

Depending on your diet, you might need to supplement your levels of B vitamins, too. Though readily available in animal proteins (200g of turkey will provide your recommended dose of B6; two to three scrambled eggs supply

‘We need to move past the idea that immunity is something you can “boost”’

the daily 1.5mcg RNI of B12), they can be harder to consume as part of a vegetarian or vegan diet – which 14% and 1% of Brits currently follow, respectively. Likewise, iron is most commonly found in red meat and seafood, so you may need to take a supplement if you aren’t regularly consuming these things. Stick to supps that use the best-absorbed compounds, advises Dr Ruxton, which are ferrous fumarate, ferrous sulphate and ferrous gluconate (yes, it pays to look closely at that ingredients label), and take alongside something high in vitamin C, like a clementine, to maximise absorption.

So, should you be supplementing your immunity? Yes, if you follow a diet that makes the essential micronutrients harder to come by, but it’s an approach that should be based on your specific needs, rather than fear of a compromised immune system. Dr Macciochi suggests exercising particular caution around any product that claims to ‘boost’ your immunity. ‘We need to move past the idea that immunity is something you can ‘switch on’ or ‘boost’ as, scientifically, there’s no way to boost your immune system,’ she explains, noting that attempting to do so could even be harmful. ‘The immune system is designed to damage the germs that are trying to infect you, so if you do have an overexuberant immune response, it could cause some collateral damage to your own tissue.’ In lieu of a ‘boost’, she recommends a holistic approach to immunity; a routine that includes upwards of seven hours of sleep each night, regular heart-rate raising workouts and keeping a lid on your cortisol levels. Two complex topics; one surprisingly simple strategy.