Scientists have long trumpeted an overall healthy lifestyle – adequate exercise, no smoking and limiting alcohol, getting enough sleep, and keeping stress levels in check – as the best way to help our bodies fend off bacteria and viruses. But the foods we eat can also play a role. And when we’re heading into cold and flu season (and still aware of COVID-19 threats), taking proactive measures for your health is a wise move.
That said, there actually isn’t much research drawing direct causation between food and immune system function. But don’t be alarmed. There are many studies that indirectly link certain foods to an improvement in immunity – mostly thanks to things like micronutrients that support cells and help them do their job, or by supporting other bodily tasks that then frees up our immune system to do its job.
The reason why it’s not as simple as ‘eat some blueberries and you won’t get sick” is because the immune system isn’t one thing that we can target. It’s actually a complex system comprised of several different areas throughout our body – think blood, T-cells, bone marrow, and organs – that work symbiotically to ultimately protect your body from external threats. To keep this system functioning efficiently and effectively, we need to be feeding the whole system.
And while determining causation regarding foods that boost immunity is tricky, there is lots of research showing that nutrient deficiencies (like in diets high in processed foods and refined sugar, and low in fruits and vegetables) are linked to a suppressed immune system, according to Harvard Health.
So What Kind of Nutrients Do I Need?
“A healthy, well-balanced, varied diet is definitely what's going to set you up for a strong immune system,” says immunologist Megan Meyer, on everydayhealth.com.
Some foods have anti-viral and antimicrobial properties, helping to fight off infections that have made their way inside the body. Herbs and spices are your friend when it comes to this kind of damage control. Cloves, oregano, thyme, cinnamon and cumin are tops for preventing the growth of some bacteria, as reported in the International Journal of Molecular Science. Garlic and onion can serve the same purpose.
Did you know protein helps your immunity? The amino acids in protein help build and maintain immune cells, while zinc – found in meat, poultry, oysters, and beans – is crucial to the proper functioning of white blood cells, which help the body identify and fight disease.
Plant-based foods help reduce inflammation in the body. When your body is busy fighting inflammation for a prolonged period of time, the immune system is overworked, leaving the body susceptible to major issues like heart disease, cancer, and type-2 diabetes. Filling up on fruits and vegetables is key to reducing inflammation.
Focusing on fruits and veg also means you’ll be getting lots of micronutrients, many of which are key to immune system function. Zinc, folate, iron, selenium, copper, and vitamins A, C, E, B6, and B12 are all crucial.
More on Micros
Vitamin C and zinc not only support immune function proactively, but they can help you recover from a cold more quickly. To get the biggest bang for your buck when it comes to vitamin C (which supports the production of white blood cells), go for kiwi (which also contains vitamin K, needed for strong bones and bone marrow), oranges and grapefruit, bell pepper, strawberries, pineapple (also great for antioxidants), and pomegranates (another vitamin K hero!).
Vitamin D is imperative to the growth and function of immune cells. Found mainly in fish, eggs and dairy products, (and from the sun!), many doctors recommend taking a vitamin D supplement, especially once we head into the winter.
Fibre helps the gut function properly, feeding the good bacteria found there, which in turn supports the immune system. In fact, a whopping 70% of our immune system is housed in our gut! Pears are an excellent source of fibre. And did you know you can eat the skin on kiwis? Doing so boosts the fibre content by 50%. Whole grains, oatmeal, dried fruit (unsweetened), and legumes are also good choices.
Foods high in omega-3 fatty acids (found in salmon) and the amino acid arginine (found in fish, meat, and whole grains) have also been found to enhance the immune response, as reported on everydayhealth.com.
Vitamin E (an antioxidant important in preventing cellular damage), magnesium (important for bone health and supporting numerous body functions), and selenium (which decreases inflammation) are also key. Nuts and seeds are a great way to to meet your daily needs. But remember that a little goes a long way – nuts are high in fat and calories, but pack a potent nutrient wallop. Just ONE Brazil nut, for example, provides 100% of your daily selenium needs.
Say What? Can Chocolate Support Immunity?!
While a direct link between dark chocolate (at least 70% cacao) and immune functioning has yet to be found, there is a fair amount of research that infers a positive relationship. Dark chocolate is high in flavanols, a potent antioxidant, which help reduce inflammation, and is also high in magnesium and fibre. It also helps increase blood flow.
Research also shows that dark chocolate has a role to play when it comes to mood and stress levels, helping us actually feel better. “Bidirectional pathways connect the brain and the immune system and provide the foundation for behavioural influences on immune functions,” according to a study in the International Encyclopedia of the Social & Behavioural Sciences.
So grab that dark chocolate bar! Research shows that dark chocolate actually contains more antioxidants than “super fruits” like blueberries, pomegranates, and cranberries.
A Couple of Things that Couldn’t Hurt
While other natural supplements and herbal remedies are often touted as having powerful effects on our immune system, the jury is still out, according to Harvard’s School of Public Health. Green tea (filled with antioxidants and polyphenols), and the herb echinacea (also rich in antioxidants and often taken at the onset of a cold) may or not help with immune system function. Limited studies (and no human ones) seem to indicate a correlation, but more research is needed.
“Scientists don't know, for example, whether an herb that seems to raise the levels of antibodies in the blood is actually doing anything beneficial for overall immunity,” according to Harvard Health.
Overall health and wellness is boosted by a varied diet with plenty of fruits and vegetables, lean protein and whole grains, as well as a lifestyle that includes adequate exercise and sleep, and efforts to keep stress in check. A healthy, well-functioning immune system is no different. If you take a comprehensive, whole-body approach to immunity, you’ll be doing your entire self a favour.
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