Who wouldn’t want to erase the runny nose, coughs and sneezes that blight most of us during the winter months? And if you have a young family or are in regular contact with children, you might find you succumb to the sniffles a little more often than most, says registered nutritionist Kerry Torrens.
All of which makes a low-cost, safe solution, such as supplementing with vitamin C, attractive – but would you be wasting your money?
What is vitamin C?
Vitamin C (ascorbic acid) is a water-soluble vitamin that the body can’t make and doesn’t store either. This means we have to obtain it from the food we eat and because vitamin C is water-soluble and not stored, the body excretes any excess via the urine.
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Can you destroy vitamin C through cooking?
Fruit and vegetables are the best sources, so it’s no surprise that 90% of our daily intake comes from them. It’s worth saying that vitamin C is easily damaged by heat and storage, so worth giving this some thought when storing, preparing and cooking produce. Ideally, store fresh produce in a cool, dark place or in the vegetable drawer of your fridge, prepare just before you need them and lightly steam or microwave, rather than boil.
As well as acting as an antioxidant, research suggests that levels of vitamin C are 10 times higher in our white blood cells than in blood plasma; white blood cells play a frontline immunity role, protecting us from viral and bacterial invasion. We also need vitamin C for the formation of healthy membranes, including those of our nasal passages and our respiratory system.
Can vitamin C cure a cold?
A 2017 study, published in Nutrients, investigated the role of vitamin C on infections and found that a number of controlled studies reported vitamin C to shorten and alleviate the common cold and even prevent symptoms under specific conditions and in certain groups of people – most notably in those exposed to extreme cold and/or experiencing acute physical stress such as marathon runners.
However, the study couldn’t conclude on the amount of vitamin C that made an effective dose. That said, a more recent 2023 meta-analysis, reported in BMC Public Health, suggested 1,000mg of vitamin C per day, commenced as soon as you contract a cold, may reduce the impact of symptoms and shorten their duration, as long as your symptoms are ‘severe’ as opposed to ‘mild’.
In the UK, the daily recommended intake for vitamin C is 40mg, an amount that should easily be obtained from your diet. For adults, the tolerable upper level that is thought to pose no risks, is 2,000mg per day. That said, taking high doses consistently may be problematic for some people, especially those with sensitive digestive systems who may experience diarrhoea and nausea, while others may be at increased risk of kidney stones.
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Vitamin C isn’t the only nutrient cited to reduce the length and severity of a cold; a 2024 review of 34 studies concluded that although zinc had little to no effect on prevention, when taken as soon as cold symptoms started, it may reduce duration. Furthermore, a 2012 study in the Journal of International Medical Researchsuggested combining high dose vitamin C with zinc may bring about faster symptom relief.
All that said, the very best strategy for immune support has to be eating a plentiful array of fruit and vegetables, including green leafy vegetables such as chard, kale and spinach as well as peppers, peas, kiwifruit and citrus fruits. If you do want to supplement, then vitamin C is a relatively safe and low-cost option and combining it with zinc may provide modest relief from symptoms. However, for most of us, supplementing is unlikely to stop us catching a cold in the first place.
There’s no need to boost your immunity for winter – a healthy, robust immune system that will do its best to protect you from infection is one that is in balance. An immune system that’s overactive could result in allergies, auto-immune conditions and chronic inflammation. Aim to support your immunity with good nutrition, adequate activity and restful sleep.
