Nutrition for colds & flus

Nutrition to prevent or treat the common cold

The weather has changed for the worst over the past while, with temperatures dropping and a turn for rain and darkness. At this time of year people start spending more time indoors, on public transport and are less likely to be out exercising in the fresh air. As a result, people are more often in close proximity to each other in damper environmental conditions, even in the current ‘Covid-19 era’, although it is certainly not ideal. With all of these factors, colds, infections, coughs and other respiratory illnesses spread more easily and become more frequent. We have entered the “cold season”. Everyone would like to avoid the common cold, so a frequently asked question at this time of year is ‘which foods can boost my immune system to prevent or treat a cold?’ Fortunately, there are some common sense approaches for reducing your chances of “catching a cold”, and some simple nutrition practices that may help to reduce the symptoms and the duration. These should be taken into account in in conjunction with public health advice regarding hand washing, physical distancing and sneezing & coughing etiquette.

The importance of sleep

Apart from making a conscious effort to increase your intake of nutrient-rich foods such as fruit & vegetables to support your immune system, make sure you are getting sufficient sleep, as inadequate sleep will quickly lead to you becoming run down and more open to infections. Aim for 7-9 hours per night of good quality sleep. Iit can be helpful to keep a sleep diary and note any particular triggers which disrupt your sleep or make it more difficult for you to fall asleep.

General nutrition

A balanced, nutrient-rich diet is unquestionably the most important factor for helping to prevent frequent occurrence of colds and other infections. Nutrient-rich foods (principally fresh fruit and vegetables) will support your immune system to fight off pathogens that can lead to the development of a cold or infections. If you do catch a cold , then you might not be able to cure it (not even antibiotics) but there are certain vegetables, fruits and supplements that have been found to reduce the symptoms and duration.

Vitamin C

Vitamin C supplementation has been linked with reducing the incidence and symptoms of colds and flus for decades. Ironically, despite the well-known association, vitamin C has not been conclusively shown to reduce either the incidence or symptoms. Some studies have found that vitamin C is effective for treating colds but only in people under short-term stress such as those who were exercising, while others found it offers no assistance in prevention or treatment of colds. On the positive side, research carried out in Helsinki involving more than 11,000 people found that male teenage swimmers who caught a cold and were given a vitamin C supplement got rid of their cold almost twice as fast as those who didn’t take any vitamin C. The researchers also found that children also appear to be more responsive to vitamin C supplementation compared to adults. The recommended intake of vitamin C when sick is a 1 gram daily dose.

Foods rich in vitamin C

If you are looking for some vitamin C-rich foods (because lets face it, natural foods are always going to be a better option than supplements) here are some suggestions for vegetables: red bell peppers, broccoli, Brussels sprouts, kale, snow peas, and sweet potatoes; and fruits: cantaloupe, grapefruit, strawberries, kiwi, mangoes, nectarines, orange, papaya, , strawberries, and tomatoes.


Zinc is an essential nutrient in the human diet, with seafood, meat, nuts and seeds being particularly good sources. Zinc appears to play an important role in the immune system, but exactly how it exerts it’s effects is not entirely clear. When zinc is taken within 24 hours of cold symptoms appearing, it can cut the duration of a cold by an average of a day and may also reduce the severity of symptoms. Other research suggests it can cut the duration of colds down to four days from seven days, and reduce coughing episodes down to two days from five. Although there are no set guidelines, the general recommended daily dose is a minimum of 75 mg daily throughout the duration of the cold.


Probiotics are bacteria that help maintain the natural balance of organisms (microflora) in the gut and intestine. Having a healthy gut with an optimum blend of “healthy” bacteria has been linked with improvements in health through reductions in inflammation and boosting immune function. Research suggests that supplementing with probiotics can help prevent upper respiratory infections (URTIs), which include the common cold. Probiotics have also been shown to reduce the severity and duration of colds, presumably by supporting the body’s ability to produce infection-fighting immune cells. When purchasing a probiotic, purchase a product containing both lactobacilli and bifidobacteria. They are the two most important forms of probiotic bacteria for promoting and optimum balance of good bacteria. Aim to take 2-10 billion live cells per dose. It is also important that we ‘feed’ the good bacteria in our guts with ‘prebiotics’. Prebiotics are often referred to as ‘fertilisers’ for the gut and can be found in foods such as garlic, leeks, onions, asparagus and bananas.

Omega 3 fats

Fats in the form of an omega-3 fish oil supplement may be another potential supplement worth taking to support the immune system. Omega-3 fatty acids are known to play an important role in managing inflammation in the body as well as supporting the body’s immune system. Research in animal studies has shown that EPA and DHA (the most abundant omega-3 fats found in fish) can boost the level and activity of immune cells in the body. So, along with the other potential benefits of consuming adequate levels of omega-3 fats, they may help when trying to fend off a cold. Foods rich in omega 3 include oily fish, nuts and seeds and some plant oils like flaxseed and canola oil.

Vitamin D

Optimal Vitamin D levels are important for reducing risk of certain diseases and recent research has linked low Vitamin D levels to an increased risk of respiratory diseases. For a full overview of Vitamin D, COVID-19 and supplementation please read this comprehensive blog. 

Green tea or herbal tea

Tea has been used by people feeling sick and wanting to warm up for generations. Anecdotally, tea certainly is known to be a comforting drink but it may also offer some genuine benefits to the immune system to prevent or help fight off infections. All tea—black, green, or white—contains a group of antioxidants known as catechins, which have effects on levels of inflammation in the body. There is no guideline as to how much you should drink, but in the case of green tea, several cups per day are associated with potential health benefits.


It may be stating the obvious, but staying hydrated is hugely important when you have a cold or URTI. Not only do you require fluids to carry out basic bodily functions and deliver vital nutrients to the body’s cells, but also to maintain body temperature. Depending on severity, a high body temperature and sweating, together with coughing, are common symptoms and each result in increased fluid losses compared to being healthy. Hence it is hugely important that you are replacing lost fluids. Additionally, fluids help transport waste products and toxins out of the body, which is a vital function when aiming to get over a cold. Consume at least three litres of fluid per day through water and teas of choice. Check out this blog to find out more about your fluid needs!


Fresh ginger root not only tastes great it also contains a variety of naturally-occurring molecules that are suggested to reduce pain and combat inflammation that may help with your cold symptoms. There are multiple ways that ginger can be used, but the way to gain the greatest benefits from fresh ginger is to slice, grate or chop it into dishes. Perhaps the best way to consume it when suffering from a cold is by grating it into a herbal tea with some lemon. For more information on the health benefits of ginger check out this blog.


These pungent cloves may offer more than just great flavour for your food. Garlic contains allicin, a sulphuric compound that produces potent antioxidants. It certainly no harm to add some extra garlic to your cooking if you are feeling under the weather. Don’t worry about the smell, you should be keeping your distance from friends and family anyway!

Final word

It is an old cliché but it remains true that “prevention is better than cure”, and it is certainly true when it comes to colds and similar illnesses. Eating a balanced diet that provides your body with sufficient energy, fluids and essential nutrients is vital for keeping your immune system strong and preventing colds. If you do develop a cold, taking a systematic approach of using more natural anti-inflammatory and nutrient-rich foods like ginger, garlic, green vegetables and citrus foods can only help your body’s immune system. In the case of supplements, vitamin C, Vitamin D, probiotics and zinc have been shown to at least reduce the symptoms and duration of colds, so although they won’t cure you, there is certainly no harm in taking them and they may offer some help getting you back to feeling yourself. In the current climate, it is also imperative that we all follow public health guidelines in relation to COVID-19. Whilst we can make good food choices to support our immune system, there is no replacement for public health guidelines to minimise your risk and protect your health.