Vitamin C: A Practical Guide for Everyday Health

Vitamin C is one of the best-known vitamins, yet it is often misunderstood. Many people associate it with colds or immune "boosting", while others assume supplements are always necessary. In reality, vitamin C plays a steady, supportive role in everyday health, and most people in the UK can meet their needs through diet alone.

Understanding what vitamin C does, when supplements may be helpful, and where common myths come from can help you make informed choices without unnecessary supplementation.

What is vitamin C?

Vitamin C, also known as ascorbic acid, is an essential nutrient that your body cannot make on its own. This means it must be consumed regularly through food or supplements. Because vitamin C is water-soluble, the body does not store large amounts, so a consistent intake is important.

Vitamin C supports several normal body processes. It is involved in the production of collagen, a structural protein found in skin, blood vessels, cartilage, and connective tissue. It also contributes to normal immune function, helps the body absorb iron from plant-based foods, and acts as an antioxidant, helping protect cells from everyday damage.

Why vitamin C matters for everyday health

Vitamin C contributes to health in ways that are gradual and supportive rather than dramatic or immediate.

It plays a role in normal immune function, helping immune cells work as they should. This does not mean vitamin C prevents illness, but having enough supports the body’s natural defences.

Vitamin C is also essential for collagen formation, which is important for skin integrity and wound healing. Without adequate vitamin C, the body cannot repair tissues efficiently.

In addition, vitamin C acts as an antioxidant, helping neutralise substances that can damage cells over time as part of normal metabolism and environmental exposure.

Vitamin C and colds: what the evidence actually shows

Vitamin C is often linked to preventing or treating colds, but the evidence does not support many of the common claims.

Research shows that taking vitamin C regularly does not prevent most people from catching colds. However, it may slightly reduce how long symptoms last, typically by around one day in adults.

Vitamin C appears to be more helpful in specific situations, such as for people undergoing intense physical stress in cold environments. For the general population, starting vitamin C after cold symptoms begin does not meaningfully shorten the illness.

The most practical takeaway is that maintaining adequate vitamin C intake through diet supports overall health, but high-dose supplements are not a cure for colds.

Signs your vitamin C intake might be low

True vitamin C deficiency (scurvy) is rare in the UK, but consistently low intake can cause milder symptoms.

Possible signs include:

Unusual tiredness or weakness
Easy bruising or bleeding gums
Poor wound healing

These symptoms are not specific to vitamin C deficiency and can have many other causes. However, they may be a reason to review dietary intake or seek advice if symptoms persist.

Getting vitamin C from food

Most people in the UK can meet their vitamin C needs through diet alone. Vitamin C is found in a wide range of commonly eaten fruits and vegetables.

Good dietary sources include citrus fruits, berries, kiwi fruit, peppers, broccoli, Brussels sprouts, and potatoes. Even foods not typically thought of as rich sources, such as potatoes, can contribute meaningfully to daily intake.

Vitamin C is sensitive to heat and water, so steaming vegetables rather than boiling helps preserve more of the vitamin. That said, cooked vegetables still contribute valuable amounts, and variety is more important than perfection.

Vitamin C supplements: what you need to know

Food should always be the primary source of vitamin C, but supplements may be useful in certain situations.

Vitamin C supplements are most often considered by:

People who eat very little fruit and vegetables
Smokers, who have higher vitamin C requirements
Older adults with reduced appetite or limited diets

For most adults, a supplement providing 40–80 mg per day is sufficient if supplementation is needed. High-dose products containing 500 mg or more are widely available but rarely necessary for general health.

Pharmacist comment

"Vitamin C is important for everyday health, but it’s also one of the nutrients people tend to over-supplement. Most adults get enough from a balanced diet, and if a supplement is needed, low-dose products are usually sufficient. Taking very high doses doesn’t prevent colds and can cause digestive upset, so it’s best to keep things simple." - Alessandro Grenci, Superintendent Pharmacist

Can you take too much vitamin C?

Vitamin C has a good safety profile, but high supplemental doses can cause side effects.

Taking large amounts, particularly above 1000 mg per day, may lead to stomach discomfort, diarrhoea, or bloating. These effects usually resolve once intake is reduced.

People with certain medical conditions, such as iron overload disorders or a history of kidney stones, should avoid high-dose vitamin C unless advised by a healthcare professional.

Who should consider supplements most?

While supplements are not essential for everyone, they may be helpful for:

People with very limited fruit and vegetable intake
Smokers or recent ex-smokers
Older adults with reduced appetite or dietary variety

In most cases, supplements should support — not replace — a balanced diet.

When to speak to a healthcare professional

You should seek advice if you have persistent symptoms such as unusual fatigue, easy bruising, or poor wound healing, or if you have medical conditions that affect nutrient absorption.

People taking regular medication should also check with a pharmacist or GP before starting supplements, as vitamin C can interact with certain medicines.

Pregnant and breastfeeding women should seek advice to ensure they are meeting, but not exceeding, recommended intakes.

Final thoughts

Vitamin C is an essential nutrient that supports immune function, skin health, and tissue repair. For most people in the UK, a varied diet containing plenty of fruit and vegetables provides all the vitamin C needed.

Supplements can be useful for certain groups, but higher doses are rarely necessary and offer no added benefit for everyday health. A food-first approach, supported by sensible supplementation where needed, is the most practical and evidence-based way to maintain healthy vitamin C levels.

Sources

Written by Christian Jakobsson