KEEPING GUARD
Boost your immune system with our no-bs guide
Immunity science: two words you might have skipped over in the past that now feel incredibly important. But how much do you really know about the suited heavies (oh, all right, the cells, organs and organ systems) whose job it is to protect you from threats? Consider this your science-backed guide
THE IMMUNE SYSTEM – TELL ME MORE...
How your body builds and maintains its safety operation is impressive – and impressively complicated. ‘The immune system makes it sound like it’s one thing, but it’s more like a collection of various components that work together,’ explains Dr Jenna Macciochi, immunologist and author of Immunity: The Science Of Staying Well. That includes organs like the skin, the lymph nodes and bone marrow, as well as cells, molecules and tissue. Essentially, it’s everywhere. ‘You’ll find immune cells in every part of the body, be that the brain, the gut, the blood or the skin – but they cluster in the places where you’re more likely to find germs,’ adds Dr Macciochi. Places like the airways, which might be exposed to respiratory germs, and the gut, which might be exposed to germs via food and drink. The latter contains around 70% of the immune system.
HOW DOES IT WORK THEN?
‘The first line of defence is the innate immune system,’ says Dr Macciochi.
‘If the cells that line these areas detect a pattern of germs that’s common to viruses or parasites, they activate a non-specific inflammation to try to make a hostile environment to stop the germ from taking hold.’ Think: heat, pain, redness and swelling. If this isn’t enough to clear the infection after a few days, your body shifts to something called the adaptive immune response. ‘This is made up of white blood cells called T cells [T lymphocytes, which produce cytokines - proteins which trigger inflammation] and B cells [B lymphocytes, which produce antibodies],’ adds Dr Macciochi. ‘The response is unique to that infection. The T and B cells clone themselves to produce an “army” of these specific cells before leaving a small population of “memory cells” that stay in your body to produce a fast response if you were to encounter the same virus again.’ For some viruses, like chickenpox, these memory cells protect you for life. Currently, estimations for Covid-19 are that immunity lasts three or four months. But this could change as we learn more.
WHY MIGHT ONE PERSON GET ILL WHILE SOMEONE ELSE IS FINE?
For starters, we’re all immunologically diverse. This is important, since we’d have been wiped out as a species by now if we weren’t. This is partly down to genetics – it’s estimated that around 20% to 30% of your immune system is inherited from your parents. As for the rest? Dr Macciochi struggles to fit all the things that influence your immune system on to one lecture slide. ‘It’s everything from how good your gut health is to how many infections you’ve been exposed to; your diet, sleep and exercise and how much adipose tissue, or fat, sits around your middle,’ she says. This lack of understanding of how each of our immune responses will react to the same virus is part of why social distancing has been critical in the pandemic. However, Dr E John Wherry, director of the Institute for Immunology at the University of Pennsylvania, predicts that, within a decade or so, we could get to the point where your GP is able to give you an immune score, just like you get a blood pressure reading.
CAN YOU REALLY ‘BOOST’ YOUR IMMUNITY?
Scientifically, no. While there’s some evidence that your requirement for vitamin C goes up when you’re fighting an infection, Dr Macciochi points out that it’s easy to get from a balanced diet, so you shouldn’t need to supplement it further. In fact, taking a reactive approach (read: chugging a litre of OJ at the first sign of a cold) is the opposite of how you should be thinking about immunity. ‘We need to avoid thinking about immunity as something you can switch on or boost,’ she explains. ‘It’s designed to damage the germs that are trying to infect you, so by virtue of that, it causes some collateral damage to your own tissue.’ Interestingly, doctors suspect an over-exuberant immune response – known as a cytokine storm – could explain persistant inflammation in multiple organs, including the lungs, long after exposure to Covid-19. As for what you can do to keep your immune system in fine fettle? It’s the stuff you’ll already know: good nutrition, a decent stretch of shut-eye each night and keeping your stress levels in check. ‘There’s nothing that can make you invincible,’ cautions Dr Macciochi. ‘But a consistently good approach to diet and lifestyle will mean your immune system will work at its best.’ Put down the OJ and turn the page for the lifestyle shifts worth making.