Our immune system is not just one single thing in one place - it is a very complex, multi-layered defence system made up of a collection of proteins, organs and parts of the body that work in unison to protect us… it’s everywhere, not just one specific organ.
Cells are our basic units of life and immune cells are constantly sending signals to let other cells know what is happening in the body. They use compounds called cytokines (proteins) to communicate with one another a bit like chemical messengers A cell releases cytokines and this binds to another cell’s receptor - the cell then does what is required at that moment. Cytokines basically help to regulate the immune response.
It is vital to keep your immune system in tip-top shape so it is in optimum condition to fight off any illness or infection - this is especially important during these challenging COVID times.
Remember - every time you eat, you have the power to nourish your body and keep that army of immune cells strong.
The best way to support immunity is to enjoy a varied, nutrient-dense diet based around whole foods that are as close to nature as possible. These foods will provide our bodies with all the key nutrients required to keep every cell in the body in peak condition. If you were fighting a war, you would cherish your soldiers, keeping them fit and healthy and it's no different for the immune system - our white blood cells are our inner army so we must nourish them.
Equally, try to reduce or avoid foods that cause damage to the immune system such as over-processed foods and simple sugars (fizzy drinks, sweets, sweetened cereals and white goods, such as white pasta, rice & flour). Try to swap white goods for wholegrain versions. These complex carbohydrates are slow to digest and will offer a drip feed of energy rather than surge of sugars than is inevitably followed by a dip. Continued high blood sugars or fluctuations in blood sugars can suppress the immune system so it won’t be in peak condition to protect you.
Nutrients all work together in synergy to ensure our bodies work optimally but here are a few key nutrients that are particularly beneficial for a robust immune system, some will be very familiar, others less so.
VITAMIN C - We all reach for vitamin C when a cold looms but do you know why? Vitamin C is a powerful anti-viral nutrient used by white blood cells to help destroy pathogens and infected cells. Scientific studies have show that it can decrease the duration of a cold or infection (1). Vitamin C is water soluble so doesn’t store in the body - you need to top up your vitamin C daily to keep levels high. Foods: sounds like a cliché but ‘eat the rainbow’ and it’s not just oranges that contain vitamin C. Include red peppers, broccoli, cauliflower, spinach, leafy greens, kiwi. 100mg = 1 cup broccoli, 1/2 red pepper
ZINC - vital for supporting the immune system. As well as being antimicrobial, zinc is used by our white blood cells to strengthen the way in which our immune system fights any pathogens they encounter and it keeps the taste buds healthy so vital to optimise zinc levels if sense of taste and smell have vanished due to coronavirus. Zinc has performed well in clinical trials showing that it reduces the severity as well as duration of colds and upper respiratory tract infections. Foods: shellfish, eggs, pumpkins seeds, cheese, nuts (30g portion), cardamom
VITAMIN D - the sunshine vitamin - receptors for Vitamin D have been found on the surfaces of many immune cells, showing that it is vital for the functioning of the immune system. It can reduce inflammation, increases the production of antimicrobial proteins and helps the immune cells fight viruses. Vitamin D deficiency has been linked to a compromised immune system (3). Foods: as well as sunshine include full-fat dairy products, mushrooms, eggs and oily fish.
VITAMIN E - a fat-soluble nutrient that acts as a powerful antioxidant so protects cells from damage and helps the body fight infection. The body uses vitamin E to regulate immune function. Foods include nuts and seeds, salmon, leafy green vegetables.
POLYSACCHARIDES - specialised sugars that exist in certain foods and can have wondrous effects upon immunity. They have been shown to increase the production of white blood cells (our immune system’s army), and their response to pathogens or damaged cells. Just a small amount of these compounds daily can really give the immune system a bit of a kick - making it ready to defend. Foods include mushrooms especially shiitake and maitake, as well goji berries.
PROBIOTICS AND PREBIOTICS - Gut health is vital for immunity as 70% of our immune cells are found in the lining of our gut wall. The trillions of gut bacteria that live in our colon have hundreds of functions, one of which is regulating the immune system to keep it strong and in a state of balance. Supporting your gut bacteria by eating probiotic and prebiotic foods will ensure the immune cells of the gut wall are protected and primed to fight off invaders.
Probiotics are foods that contain good bacteria such as plain yoghurt, kefir and other fermented foods such as sauerkraut and kimchi.
Prebiotics are a type of dietary fibre which human cells can’t digest but on which the bacteria feed and flourish. These are foods such as artichokes, asparagus, leeks, onions, garlic and bananas. Ensuring you have adequate of these fibres in your diet will help stimulate friendly bacteria and in turn strengthen your immune system. Aim for at least seven portions of fruit and vegetables a day (variety is vital) and include complex whole grains such as oats and quinoa.
SELENIUM - This mineral is the precursor to one of our bodies most powerful antioxidants called glutathione. Antioxidants protect our cells from damage, which reduces inflammation and enhances immunity. Clinical trials have proved that selenium can be a powerful support to the immune system (4). Foods include Brazil nuts, brown rice, chicken and mixed seeds.
Caroline is a nutritional chef who creates personalised menu plans and recipes to support personalised nutrition recommendations. She also runs relaxed and informative cooking demos under the name of Everyday Healthy Cooking which take place in her kitchen in Wandsworth.