As we get closer to winter and the subsequent rise in colds, flu and likely, covid-19, more of us are hunting out ways to keep ourselves healthy.

However, research by the Fruit Juice Science Centre states that 53.4% of people in Leeds are unaware that they are more likely to pick up viruses if the immune system is compromised.

So, how do we Improve our virus-fighting systems? It’s not as difficult as you might think. In fact, adding certain nutrients to your day to day diet could make all the difference.

Vitamin C
There’s a reason we turn to orange juice during times of sickness; new research by the Fruit Juice Science Centre has revealed that just one 150 ml glass of 100% fruit juice provides a staggering 84% of the Nutrient Reference Value (NRV – the minimum we should consume for normal health) for vitamin C. During times of illness, experts say we may need more than double the NRV – around 200 mg of vitamin C daily.

And this vitamin is essential for our immune system; it not only influences the growth and function of immune cells, it also supports the skin and gut barriers against pathogens, acts as a powerful antioxidant, and encourages mobilisation of white blood cells to sites of infection to kill off pathogens.

However, it’s not just when you’ve been struck down with the sniffles that you should consider drinking a glass of orange juice.

More than 43.1% respondents quizzed in Leeds believe wrongly that the body stores vitamin C and as long as you’ve consumed lots on one day, your body will have enough for the next day. However, this isn’t the case and a daily supply is needed.

Dr Gill Jenkins, GP and broadcaster, explains that in the UK many of us fail to reach optimal vitamin C intakes as most people don’t eat the recommended five daily servings of fruit and vegetables. Shockingly, fewer than one third of 19-64-year olds hit their quota.

That’s why it’s a good idea to load up on fruit and veg, particularly those rich in anti-oxidant vitamin C such as tomatoes, red and green peppers, kiwi fruit, broccoli and potatoes. One daily serving of 100% juice can be part of this.

Vitamin D
The sunshine vitamin is in short supply during the UK’s winter months, so the UK government advises everyone consider a year-round supplement of 10 micrograms of vitamin D a day to keep bones and muscles healthy.

More recent studies have found vitamin D receptors on several types of immune cells, suggesting that it also has an immunity benefit. Added to this, low vitamin D levels in blood increase the likelihood of respiratory tract infections, so it’s essential to keep stores topped up.

Vitamin D is only found in a small number of foods which is why we rely on summer and autumn sunshine to hit our vitamin D targets. But even this isn’t fool proof given the UK’s ever-changing weather.

With nearly a fifth of adults failing to reach the minimum cut-off set by the UK Department of Health (25 nmol/litre) of vitamin D blood levels, it’s time to up our game with this essential vitamin.

As well as supplementation, include vitamin D-rich foods like oily fish, eggs, dairy products, liver, fortified foods and mushrooms.

This water-soluble B vitamin is essential for normal immunity, including antibody production and function.

It’s also vital for cell health, says Dr Jenkins, as during pregnancy, “a lack of folic acid is associated with neural tube defects (NTDs) such as spina bifida”. Need another reason to drink fruit juice? A 150 ml glass of 100% orange juice provides 16% of the NRV for folate. To increase your intake of folate even further, add whole fruit, nuts, seeds, beans, peas and green leafy vegetables to your diet.

Omega-3 fatty acids
Whilst Omega 3 fatty acids do target and reduce body inflammation, fewer than half of those surveyed in Leeds by the Fruit Juice Science Centre actually linked omega-3s with immune function. It’s recommended that we consume 140g of omega-3s-rich oily fish a week. However, the National Diet and Nutrition Survey reveals that adults aged 19-64 years eat just 56 g a week on average -with teens eating even less! Up your omega 3s intake with oily fish (including sardines, salmon and mackerel) as well as nuts and seeds such as flaxseed, chia seeds and walnuts. Try sprinkling flaxseeds over porridge for breakfast and grilling sardines on toast for lunch.

Polyphenols, prebiotics and probiotics
These all support our gut microbiota- the complex family of bacteria that lives in our digestive tract - which in turn, can play a role in our immune health. The gut is the first line of defence against pathogens and having a healthy, balanced microbiota is the cornerstone of this.

As if the vitamin C content of 100% orange juice wasn’t enough to make you consume 150 ml a day, orange juice also contains hesperidin, a type of polyphenol particularly useful in aiding vascular function with new 2020 research claiming that hesperidin could be useful in novel drugs for covid-19.

Dr Gill Jenkins explains: “Hesperidin has attracted the attention of scientists because it binds to the key proteins of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) – meaning it could have anti-viral effects.”

New evidence also suggests that hesperidin has a prebiotic effect, encouraging more favourable bacteria to thrive in the gut. For optimum levels of hesperidin, drink packaged juice rather than home squeezed juice since commercial squeezing extracts more polyphenols. As well as orange juice, add high fibre and probiotic-rich fermented foods to your diet such as pickles, miso, kefir and sauerkraut.