Top 15 immune-supportive foods

What is the immune system?

The immune system is the body’s major safeguard against infection, illness and disease. It contains a vast network of cells, tissues and organs which coordinate the body’s defences against bacteria, viruses and toxins that may threaten our health. One of the main components of our immune system is the millions of defensive white blood cells that patrol the blood stream and lymphatic system, constantly on the lookout for suspicious signs of disease. Once detected, our immune system mounts a response to fight an infection and remembers it for the next time.

Can you really boost your immune system?

The immune system isn’t just an army defending us against invaders, it can reduce inflammation and other natural, but potentially damaging responses, if they were to go on too long. An overactive or prolonged immune response may start to target the body’s own cells, and in extreme cases lead to auto-immune conditions or chronic inflammation.

Therefore, rather than ‘boosting’ the immune system, it is better to aim to keep it healthy and balanced – fighting off invaders but supporting balance and calm when needed. What we eat, including antioxidants, phytonutrients, vitamins, minerals and fibre, may support this balance by providing the body with the nutrients required to build a protective response and to counteract oxidative damage. With this in mind, it’s best to include a wide range of colourful whole foods including fruits and vegetables from the list below – the more variety the better.

1. Blood oranges

Blood oranges are the superstars of the citrus family. They contain five times the antioxidant activity of a regular orange with the same amount of vitamin C. Research has shown that a daily glass of blood orange juice for seven days may help reduce inflammation and raise antioxidant levels in the blood.

2. Brazil nuts

Brazil nuts contain selenium, an important mineral to protect against oxidative stress. Selenium has also been shown to help the body fight viral infections so including a couple of Brazil nuts each day, as part of a meal or snack, may provide the immune system with adequate amounts to remain robust.

3. Broccoli

Research from the University of California reported broccoli may be a great addition to your diet if you’re trying to prevent a cold. Broccoli and other cruciferous vegetables are proven to help support immunity, because of their sulforaphane content - a plant chemical that switches on antioxidant genes and enzymes in specific immune cells. In doing so, they may help combat free radicals and potentially reduce the risk of disease.

4. Curcumin

Curcumin may act as an immune modulator, by influencing important immune cells including T cells, B cells and 'natural killer' cells. In addition, curcumin appears to ease inflammatory compounds called cytokines, its these that lead to the damage associated with inflammation. When consumed at low doses, curcumin may enhance our antibody responses, helping us fight off infection.

5. Dark chocolate

Dark chocolate contains minerals, including magnesium, which is vital for supporting the immune system. Magnesium helps lymphocytes bind to pathogens so they can be removed from the body. Make sure to choose the very dark chocolate (80 per cent cocoa and over), to get the most magnesium.

6. Garlic

Garlic has a long history of use as an infection fighter against viruses, bacteria and fungi. This therapeutic acclaim is largely down to an active compound called allicin. This sulphur-containing compound gives garlic its pungent smell and distinctive taste and is responsible for its potent anti-viral properties.

7. Ginger

When it comes to treating a common cold, ginger is one of the best foods for symptom relief. In one study, researchers found that ginger’s potent anti-inflammatory properties were key to its ability to help combat a cold or flu.

8. Greek yogurt

Live Greek yogurt contains beneficial gut bacteria (often referred to as probiotics) and is packed with more protein than regular yogurt. We need protein to form components of the immune system, such as anti-bodies. Studies show that people who ate probiotic foods daily had a lower risk of catching a cold than those who did not eat these foods.

9. Green tea

Green tea is frequently included on lists of super healthy foods and with good reason. It contains flavonoids, plant chemicals with an antioxidant effect that may support immunity, and have anti-inflammatory properties. According to one study, it’s the plant chemical catechin that is a powerful antibacterial and antiviral and may protect against colds and the influenza virus.

10. Kefir

Kefir benefits from a diverse composition of beneficial bacteria and yeast, and is even more diverse than yogurt. As a result, regularly eating kefir has been shown, in animal studies, to enhance intestinal immunity, and may alleviate the inflammatory response associated with allergies and asthma.

11. Kiwi

With more vitamin C than an orange and loaded with antioxidants, kiwis are bite for bite one of the most nutritionally dense fruits you can buy. Various compounds from vitamin C and fibre, to carotenes and polyphenols, have been shown to benefit immune function – all of which are found in a kiwi.

12. Oregano

Many herbs and spices are known for their immune supporting properties. Oregano is one such herb, it contains essential oils which are known for their antimicrobial, antiviral and antifungal properties and may be helpful in treating microbial infections.

13. Pomegranate

Pomegranates contains polyphenols that may help treat and prevent coughs and colds. Studies have shown that concentrated amounts of polyphenol antioxidants, like those found in pomegranate juice, may reduce the duration of a cold by as much as 40 per cent.

14. Salmon

Salmon, preferably wild, is a useful source of zinc, a nutrient that has been proven to help reduce common cold symptoms. Oily fish, like salmon, are also high in omega-3 fatty acids which assist in reducing inflammation, prevent viral infections and enhance the functioning of immune cells.

15. Shallots

Shallots contain roughly six times more protective plant compounds, called polyphenols, than regular onions. This is largely down to the quercetin content. Quercetin plays an important role in helping the body combat damage caused by oxidation that is linked to disease.

So, can we eat to improve our immunity?

What we eat may support our immune defences, and certain foods have been linked to reduced recovery time if we do get ill. As always, the bottom line is to choose fresh, whole foods as much as possible, and to eat a wide variety of colourful fruit and vegetables. By minimising packaged ultra-processed foods, you may help reduce disease risk and promote a more healthy, robust immune function.