Vitamin C: Its Role in Boosting Immunity and Fighting Infections

Vitamin C, or ascorbic acid, is a water-soluble vitamin involved in many processes in the body, and it's especially famous for its role in immunity. As a powerful antioxidant, it protects cells from damage, supports immune cell production and helps the body fight infection. Here's how vitamin C supports your immune system, where to get it and how much you need.

Why Vitamin C Matters for Immunity

Vitamin C is essential for immune cells to work properly, particularly lymphocytes and phagocytes, which are key to both your innate and adaptive immune responses. It helps in several ways:

1. Antioxidant protection: It neutralises free radicals that can damage cells, protecting immune cells from oxidative stress so they keep working well.
2. Boosting immune cells: It supports the production and function of white blood cells, including neutrophils, your first line of defence against infection.
3. Supporting antibodies: It helps the body produce antibodies, the proteins that identify and neutralise viruses and bacteria.
4. Balancing immune responses: It helps keep the immune response appropriate and can help temper excessive inflammation.

Vitamin C and Colds

Research suggests vitamin C may help reduce the severity and duration of respiratory infections like the common cold. Regular supplementation has been linked to a modest reduction in how often people catch colds, particularly those under heavy physical stress, such as athletes.

Vitamin C isn't a cure, but by supporting immune function and acting as an antioxidant, it may help symptoms pass a little more quickly and feel a little milder.

The Best Food Sources

1. Citrus fruit: Oranges, grapefruit, lemons and limes are classic sources.
2. Berries: Strawberries, blueberries, raspberries and blackberries also provide antioxidants and fibre.
3. Vegetables: Peppers, broccoli, Brussels sprouts and kale are rich sources. Red and yellow peppers contain more than many fruits.
4. Kiwi: A small fruit packed with vitamin C, great in smoothies and salads.
5. Tomatoes: Fresh tomatoes and tomato juice are easy to add to meals.
6. Potatoes: Surprisingly, potatoes, especially cooked with their skin, provide a useful amount.

How Much Do You Need?

Recommended intake varies with age, sex and life stage. For most adults it's about 75 mg a day for women and 90 mg for men. Smokers and people under significant stress may need more.

Because vitamin C is water-soluble, your body doesn't store much of it, so eating vitamin C-rich foods regularly is important.

Should You Supplement?

Food is usually the best source, but some people benefit from supplements, including those with restricted diets, certain medical conditions or higher needs.

Choose a high-quality product. Ascorbic acid is the most common form, while buffered versions may be gentler on the stomach. Very high doses can cause digestive upset and aren't recommended for people prone to kidney stones. Check with a healthcare professional before starting, especially if you have a health condition or take medication.

Beyond Immunity

1. Collagen production: Vitamin C is essential for making collagen, which supports skin, cartilage, bones and blood vessels, and helps wounds heal.
2. Iron absorption: It boosts absorption of non-haem iron from plant foods, helping prevent iron-deficiency anaemia.
3. Brain health: It's needed to make neurotransmitters, and healthy levels are linked to better cognitive function.

A Key Player in Your Health

Vitamin C supports immunity in many ways, from protecting immune cells to helping produce antibodies. Eating a variety of vitamin C-rich foods is the easiest way to keep your levels healthy, with supplements as a back-up if needed. Combined with a balanced diet, it helps build a resilient immune system and supports overall vitality.