Immune boosting fruits, vegetables and nuts

Effective Ways to Boost the Immune System

In the quest for good health and well-being, few aspects of our health are as crucial as the resilience of our immune system. The immune system is a multitude of specialised cells that serve as the body’s defence against harmful microbes, including viruses, bacteria, and other invaders. A robust immune system not only protects us from infections but also plays a pivotal role in overall health and longevity. So what are the best ways to boost our immune system?

Navigating a world with challenges to our immune defences around every corner, from adapting viruses to the demands of modern life, the importance of strong immune support cannot be overstated. Whether you are a health enthusiast eager to optimise your immune function or someone seeking practical strategies for supporting immune health in the face of specific challenges, there are several effective ways to boost the immune system for sustained well-being. 

Immune System Boosting Foods

Citrus Fruits 

Citrus fruits, including oranges, grapefruits, lemons, and limes, are renowned for their high vitamin C content. Vitamin C is a potent antioxidant that supports the production of white blood cells, crucial defenders in the immune system. Antioxidants help neutralise free radicals, which can cause cellular damage that triggers many health issues. These fruits also contain flavonoids, compounds with anti-inflammatory properties, further enhancing their immune-boosting potential. Incorporating citrus fruits into the diet provides a refreshing and tasty way to ensure the body receives an ample supply of this essential vitamin, boosting the overall resilience of the immune system. 

Berries  

Berries, such as strawberries, blueberries, blackberries, and raspberries, are important sources of anthocyanins and quercetin. Anthocyanins and quercetin help combat oxidative stress in the body, reduce inflammation, and support immune function. Anthocyanins in berries boost the immune system by supporting the function of cytokines, which control the inflammatory response. Berries can also boost the growth and multiplication of beneficial bacteria in the gut. The beneficial bacteria can then boost the activity of natural killer and phagocytic immune cells and improve the activity of other immune cells, such as T cells. The rich variety of vitamins and minerals found in colourful fruits contributes to a nutrient profile that boosts the immune system. The diverse range of phytochemicals present in these fruits provides a host of immune-boosting benefits, making them not only delicious additions to the diet but also powerful immune-boosting agents.  

Leafy Green Vegetables 

Leafy greens such as spinach, kale, and Swiss chard are nutritional powerhouses that offer a wealth of vitamins, minerals, and antioxidants. Among these, vitamin A, vitamin C, and various forms of folate play essential roles in supporting immune function. Leafy greens also provide fibre, which is necessary for a healthy gut microbiome. The beneficial bacteria in the gut feed on the insoluble fibre in these fibrous vegetables, which enables them to grow and multiply. The combination of essential nutrients and phytochemicals makes leafy green vegetables a cornerstone in strengthening the immune system to protect the body from microbial invaders.   

Onions  

Onions are one of the most grown and consumed vegetables worldwide. They contain a total of thirty-four phenolics, including seventeen flavonoids, with quercetin being the most abundant. These compounds have powerful antioxidant and anti-neuroinflammatory abilities, with flavonoids in onion peels having significant positive effects.  

Quercetin is also known for being anti-allergic due to its ability to keep the immune system in check and block the release of histamines, compounds that cause allergic reactions. For this reason, quercetin is often found in treatments for conditions such as bronchial asthma and hay fever. As well as onions, quercetin is also found in broccoli, apples, berries, grapes, certain herbs, tea, and wine. Whether incorporated into savoury dishes or used as aromatic additions, garlic and onions provide a flavuorful means of boosting immune health. 

Yoghurt and Probiotics 

Yoghurt, along with other probiotic-rich foods such as kefir and fermented vegetables, serves as a source of beneficial bacteria that promote a healthy gut microbiome. A robust gut microbiome is intricately linked to immune function, as it helps regulate the body’s immune responses. Probiotics enhance the production of antibodies and support the activity of immune cells, boosting the function of the immune system to defend the body against pathogenic microbes.  Including yoghurt and probiotic-rich foods in the diet not only contributes to digestive health but also plays a crucial role in boosting the immune system. These foods also help reduce the risk of type 2 diabetes, heart disease, and metabolic syndrome.  

Nuts 

Almonds support immunity due to their vitamin E content.  Almonds with their skin still intact have been shown to reduce the multiplication and spread of viruses, such as the herpes virus. This is due to the effects of specialised immune cells such as cytokines, interleukins, and tumour necrosis factors.  

Pistachios are loaded with anti-oxidant and anti-inflammatory compounds such as anthocyanins, flavonoids, and the carotenoids lutein and zeaxanthin. They also contain the immune-boosting vitamins A, B, C, E, and K.  

Walnuts are often celebrated as a ‘superfood’ because they contain a mix of natural substances that work together to lower the risk of cancer. Looking like miniature brains, they are packed with anti-inflammatory omega-3 polyunsaturated fatty acids that support brain health. They also contain beneficial compounds such as tocopherols, antioxidant polyphenols, and ellagitannins.  

When walnuts are eaten, ellagitannins turn into ellagic acid, which the gut bacteria then transform into bioactive substances called urolithins. Some of these, like urolithin A, have strong anti-inflammatory properties. Walnuts are high in fibre, so they are a prebiotic food for the “friendly” bacteria in the gut, helping to lower the risk of diseases such as colorectal cancer.  

Like walnuts, pecans also look like miniature brains, are packed full of anti-inflammatory omega-3 polyunsaturated fatty acids, and contain immune-boosting vitamin E, folate, and zinc. These nutrients help the body to repair, fight off infections, and also protect the DNA. This is important as damaged DNA has the potential to trigger cancerous cell growth and multiplication. Eating pecans can also help reduce cholesterol, which in turn reduces the risk of heart disease.  

Along with almonds and walnuts, Brazil nuts are beneficial nuts for the immune system. Brazil nuts are one of the best dietary sources of the anti-oxidant mineral selenium. This is needed for the health of the thyroid gland and to protect healthy DNA. Brazil nuts can boost the production of the body’s innate anti-oxidant, glutathione, which has anti-inflammatory effects. Brazil nuts have also been found to be especially beneficial for individuals with chronic kidney disease because the selenium in them improves oxidative stress and inflammation.  

 

Seeds 

Pumpkin seeds are full of nutrients, including fibre, healthy fats, protein, vitamin E, zinc, magnesium, and folate. However, they also come with a range of polyphenols, phytosterols, flavonoids, and carotenoids. This makes them very effective for fighting oxidative stress in the body. For this reason, research has found them to be beneficial at boosting the immune system. They are also effective at reducing the risk of infection by parasites, diabetes, high cholesterol, and even cancer, all because of their nutrient profile.  

 

Chia seeds are another seed that can support the immune system. They are full of fibre, both soluble and insoluble. The insoluble fibre keeps the beneficial gut bacteria happy because it serves as food to enable them to grow and multiply, crowding pathogenic, infection-causing bacteria out. The fibre also has a cleansing effect, grabbing onto chemicals that cause high cholesterol and cancer and removing them from the body. Chia seeds also contain a variety of phytochemicals, including quercetin, kaempferol, caffeic acid, and chlorogenic acid. These fight inflammation and oxidative stress, which supports the immune system.  They specifically support the health of the heart and liver and have anti-cancer benefits.  

 

Vitamins 

Vitamin C 

In addition to the benefits already mentioned above, vitamin C plays a vital role in maintaining the integrity and strength of the skin. The skin is the first line of defence in the body’s immune system, so it is important that it cannot be penetrated by bugs and germs. Vitamin C is also vital for healing wounds and cuts, which can be an entry point into the body for bacteria, causing the wound to become infected. 

Vitamin E 

Vitamin E is a powerful anti-oxidant that supports the body in overcoming the effects of oxidative stress. It also plays a crucial role in supporting the immune system by regulating cell signalling and gene expression. Vitamin E also acts as a guardian for vascular health, making it harder for components in the blood to stick to the blood vessel walls and helping blood vessels function efficiently. It also stimulates the release of prostacyclin, helping to expand blood vessels and prevent blood cells from sticking together.  

 

Immune System Boosting Herbs and Spices 

Garlic 

Garlic contains allicin, a compound known for its antimicrobial and anti-inflammatory effects. These properties contribute to a strengthened immune response, assisting the body in warding off infections. For centuries, garlic has been praised for its health benefits. The active ingredient in garlic is allicin, but cooking destroys it. 

Recent research suggests that garlic may boost the immune system’s performance by activating specific cell types like macrophages, lymphocytes, natural killer cells, dendritic cells, and eosinophils. It does this through various mechanisms, including influencing the secretion of cytokines, promoting immunoglobulin production, enhancing phagocytosis (the process of engulfing and digesting pathogens), and activating macrophages (cells that engulf and digest cellular debris and pathogens).  

Immune dysfunction is linked to the development and progression of various diseases, and garlic’s impact on cytokine secretion could be a key factor in its therapeutic effects. This means that garlic might play a role in treating and preventing conditions like obesity, metabolic syndrome, cardiovascular disorders, gastric ulcers, and even cancer. In essence, garlic seems to have a positive influence on the immune system, potentially contributing to its health-promoting effects. 

Ginger 

Ginger possesses anti-inflammatory and antioxidant properties, which can help control the ageing process. Its antimicrobial action adds another benefit by helping to treat infections. In the body, oxidative stress occurs when the production of free radicals or reactive oxygen species surpasses the antioxidant capacity. This imbalance is linked to heart diseases, neurodegenerative conditions, cancer, and the ageing process. Ginger’s bioactive molecules, especially gingerols, have demonstrated antioxidant activity in various scenarios, potentially counteracting the harmful effects of oxidative stress.  

Turmeric 

Turmeric, a golden spice from the roots of the Curcuma longa plant, has considerable benefits for the immune system. Turmeric contains approximately fifteen polyphenols, the most active and beneficial of which is curcumin. Curcumin has been found to be anti-inflammatory and has strong anti-oxidant properties.  

Research suggests that curcumin may influence the activity of various immune cells, including T cells, B cells, macrophages, and natural killer (NK) cells. These cells play crucial roles in detecting and eliminating harmful bacteria and viruses. Turmeric can support the immune system further because it is anti-microbial. It can help combat bacteria and fungi, which helps prevent infections.  

Turmeric is also anti-viral, as it inhibits viruses from replicating and spreading. It is particularly effective against the flu and human papilloma viruses, the latter of which can lead to cervical cancer if left untreated. On that note, curcumin has also been found to have anti-cancer properties.  

Cinnamon 

Cinnamon is a popular spice that comes from the bark of trees in the Cinnamomum family. It is not only known for its warm and sweet flavour, but also for potential immune system support. With that said, more research is needed to fully understand the extent of cinnamon’s impact on the immune system. Cinnamon contains several beneficial compounds, including cinnamaldehyde, cinnamic acid, proanthocyanidins, tannins, linalool, pinene, and eugenol. These compounds give cinnamon its anti-bacterial, anti-oxidant, anti-inflammatory, and anti-fungal properties. Cinnamon has also been shown to be anti-diabetic, as it can help prevent diabetes because it can help regulate blood sugar levels by improving insulin sensitivity. Cinnamon can reduce the risk of infection by viruses, as it stops the viral cells from attaching to the cells in the body.  

Basil 

Basil, a fragrant herb belonging to the mint family, offers many benefits for immune system support. Basil contains several beneficial compounds, such as D-linalool, eugenol, catechins, quercetin, kaempferol, limonene, anthocyanins, terpinene, tannins, menthol, and rosmarinic acids, along with potent essential oils (23).  

Linalool and eugenol give basil its anti-bacterial and anti-viral benefits, helping to support the immune system in warding off infections. Basil also has adaptogenic qualities. Adaptogens are substances that help the body adapt to stress and indirectly support the immune system by helping the body manage stress more effectively (25). 

Basil has been found in many studies to be useful in the therapeutic treatment of cardiovascular disease and metabolic disorders such as diabetes and metabolic syndrome. It can also support the immune system by protecting the brain and liver. This is due to its anti-inflammatory, anti-oxidant, and anti-microbial effects.  

Rosemary 

Rosemary not only adds an aromatic flavour to dishes but also offers potential benefits for immune system support. Like other herbs, rosemary contains many beneficial compounds that give it its anti-oxidant and anti-inflammatory benefits that enable it to support the immune system. These compounds include linalool, cineole, camphor, rosmarinic acid, linonene, and rosmanol. 

Rosemary has strong antioxidant properties. This is because it can stimulate the action of superoxide dismutase, an innate anti-oxidant that is produced in the body. Thyme and sage also produce this benefit. It also contains carnosic acid, which gives it anti-viral properties. It does this by blocking the viral cells from multiplying. It is especially effective against viruses that attack the respiratory system.  

Lifestyle Practices for a Robust Immune System  

Exercise 

Regular exercise offers a range of benefits that positively impact the immune system. First, it helps the lymphatic system function more effectively. This is because the lymphatic system requires regular movement to circulate the lymph, as it does not have a pump in the way that the heart pumps blood around the body.  

Physical activity stimulates the production of various immune cells, including white blood cells, which play a crucial role in the body’s defence against infections. Intense exercise over a short period of time can also stimulate the number of natural killer cells present in the body. However, doing intense activity over a prolonged period does not boost them even more. In fact, natural killer cells are reduced after a long period of intense exercise. Therefore, less is more when trying to boost this aspect of immune health.   

With that said, if you have an infection, especially from a virus, it is not a good idea to do physical exercise. This is because it has been shown to increase the replication of the virus and inflammation, especially in viruses that affect the heart and respiratory system. However, research shows that exercising regularly can boost the immune system and reduce the symptoms and length of time an individual suffers from an infection.  In the case of life-threatening viruses, such as COVID-19, someone who exercises regularly is less likely to develop complications and die. 

Sleep 

We all know that if we don’t get enough sleep, we can be grumpy, snappy, and generally not nice to be around. We can also be what is commonly referred to as “hangry,” which is not only the merging of the two words hungry and angry but also the dangerous combination of the two emotions. This is due to sleep deprivation stimulating the production of the hunger hormone ghrelin, causing us to make poor choices in the food we eat when we are tired. These include processed foods high in sugar, salt, and fat.  

This can lead to weight gain, which can affect the immune system. On top of that, eating a diet high in sugar causes inflammation, reduces immunity in just hours, and increases the risk of developing allergies.  

Sleep is closely connected to protecting against neurodegenerative diseases like Alzheimer’s. This is because during sleep, the glymphatic system clears away plaques, waste, and proteins that are key features in the development of Alzheimer’s disease. Not getting enough sleep can mess with this process. A lack of sleep can also disrupt the blood-brain barrier, which, long-term, can increase the risk of the development and progression of strokes, diabetes, and multiple sclerosis.  

On another note, sleep also plays a part in regulating learning and memory. It does this by influencing a substance called brain-derived neurotrophic factor. When you don’t get enough sleep for a long time, brain-derived neurotrophic factor levels can go down. However, a combination of short-term sleep loss and exercise can increase brain-derived neurotrophic factor in the hippocampus, a part of the brain linked to memory. Therefore, if you have had a bad night, it is well worth doing some exercise the following day, if only to tire yourself out in a bid to sleep better the following night. 

Making sure you get a good night’s sleep on a regular basis is essential to protecting the immune system. Therefore, it is important to follow good sleep hygiene tips such as sleeping in a cool, dark room, going to bed and getting up at the same time every day, avoiding screens a couple of hours before bedtime to avoid exposure to blue light, and getting exposure to natural daylight as soon as possible after waking up.  Click here for more tips on getting a good night’s sleep and overcoming insomnia 

Stress reduction to boost the immune systemStress reduces immunity

When you’re stressed, nerve cells in the sympathetic nervous system release substances that influence the immune system by interacting with receptors on white blood cells. Different types of immune cells, including natural killer cells, B cells, and T cells, have different receptors, which can affect how they respond to stress.   

Another way stress affects the immune system is through three systems in the body. These are the hypothalamic–pituitary–adrenal axis, the sympathetic–adrenal–medullary axis, and the hypothalamic–pituitary–ovarian axis. These systems release hormones like epinephrine, norepinephrine (also known as adrenaline and noradrenaline), cortisol, prolactin, growth hormone, melatonin, β-endorphin, and enkephalin. These hormones latch onto specific receptors on white blood cells, influencing how they function. Also, when individuals are stressed, they tend to drink alcohol, and their sleep can be affected, which both influence immunity.  

When we’re stressed, it can mess with how our immune system works, and this is connected to various health issues. Think of it like this: stress can make our immune system act like it’s dealing with a constant problem, such as what happens in chronic inflammatory diseases such as rheumatoid arthritis. This altered immune function doesn’t just affect our physical health; it can also make psychological issues worse. For example, in conditions like irritable bowel syndrome, stress can make stomach troubles worse because of ongoing cortisol activity.  

Stress can even lead to higher levels of substances such as proinflammatory cytokines, which have been linked to conditions like schizophrenia. Chronic stress also seems to increase the risk of developing autoimmune diseases.  Researchers are currently trying to figure out exactly how autoimmune diseases affect how our bodies respond to stress. The hope is that understanding this better will help create ways to decrease the immune responses triggered by stress and improve outcomes for people with autoimmune diseases.  

In diseases such as multiple sclerosis, stress activates certain substances in the brain that cause inflammation, making the disease worse. Having some stress management strategies can help protect the immune system. These include breathing techniques, mindfulness, meditation, and talking therapies.  

Reducing Alcohol  to Boost the Immune System

When an individual drinks alcohol, the body prioritises the elimination of that alcohol over everything else because it sees alcohol as a poison and wants to rid the body of it as soon as possible.  

Alcohol can damage the cells that line the digestive system, making it more likely for microbes and toxins to be able to pass through into the bloodstream. It can also damage the T cells and neutrophil immune cells. Another way alcohol can affect immunity in the gut is by disrupting the beneficial bacteria in the gut. The effects on the gut bacteria and lining enable bacteria to enter the bloodstream and can trigger inflammation in the liver that can eventually lead to liver disease and cancer. Drinking too much alcohol is also linked to lung and respiratory diseases.  

The affects on immunity can be caused by both long-term drinking and binge drinking. In fact, even small amounts of alcohol can affect the immune system. When under the influence of alcohol, individuals tend to be less reserved and take more risks than when they are sober. This means that they are more likely to suffer an accident, such as a burn, heavy bleeding, or even a head injury. Unfortunately, recovery and healing from these conditions can be hampered due to alcohol disrupting the immune system. Therefore, it is beneficial to keep drinking alcohol to a minimum and avoid binge drinking to protect the immune system. 

There are many ways that the immune system can be affected, such as diet, exercise, sleep, stress, and alcohol. The tips in this article go some way towards explaining how best to protect the immune system to enable the individual to live a long and healthy life. However, it is important to remember that life is for living, and the saying “everything in moderation.” In other words, you can still protect your immunity without having to give up all the things in life that you enjoy.  

References

Exercise and the immune system

Immune boosting benefits of vitamins and minerals

Berries and immunity

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