Back to Basics: Vitamin C

You've probably heard vitamin C stops you catching a cold. It doesn't, not exactly. What it actually does is more specific, genuinely useful, and better evidenced than the myth.

Vitamin C, also known as ascorbic acid, was first isolated in 1928 by the Hungarian biochemist Albert Szent-Győrgyi, and confirmed a few years later, using Hungarian paprika as his source, to be the substance that prevents scurvy. He went on to map out much of the citric acid cycle that our cells still rely on today, work that won him the 1937 Nobel Prize.

The Cold Myth, Properly Explained

A major review of the evidence found that taking vitamin C regularly doesn't reduce how often the average person catches a cold. What it does do is shorten one once you've got it: colds were around 8 percent shorter in adults who supplemented regularly, and noticeably milder. For people under serious physical strain, marathon runners and the like, regular supplementation roughly halved their chances of catching a cold in the first place. The timing matters too: starting vitamin C only after symptoms appear hasn't been shown to help. The benefit comes from topping up consistently, not reaching for it once you're already sniffling.

Where It Actually Comes From

One common myth is that the body can make its own vitamin C. It can't. Every bit of it has to come from food or a supplement. Good food sources include citrus fruits, strawberries, blackberries, peppers, broccoli, Brussels sprouts and even potatoes. The UK's reference intake for adults is 40mg a day, roughly what you'd get from a single orange.

What It Does for You

Vitamin C is involved in hundreds of processes in the body. It's essential for making collagen, which keeps connective tissue strong, and it helps your body absorb iron. It also has antioxidant properties, and vitamin C contributes to the normal function of the immune system.

A long-term lack of vitamin C causes scurvy, most famously associated with sailors on long voyages without fresh fruit or vegetables. It sounds like a relic of history, but cases still turn up today, usually linked to a very limited diet.

For most healthy adults eating a varied diet, outright deficiency is genuinely uncommon, one large UK study put it at under 2 percent of the general population. It's a different picture for older adults and anyone on a more limited diet, where deficiency has been measured at well over ten times that rate. If that sounds like you or someone you're buying for, it's worth paying closer attention to.

Worth Thinking About as Winter Approaches

As the colder months set in and cold and flu season picks up, it's a natural time to check whether you're getting enough vitamin C day to day, and whether topping up now, before symptoms show up, is worth adding to the routine.

Vitamin C won't stop a cold arriving, but taken consistently, it can make the one you do get shorter and milder. That's a smaller promise than the myth, and a truer one.

Based on the UK reference nutrient intake for vitamin C and a major Cochrane review of vitamin C and the common cold. Looking after your immune system more broadly? Browse our Immune Support range.