How more vitamin C could transform your mood and slow cognitive decline - and here are the best foods to load up on it

We love vitamin C, it seems — it’s one of the most purchased supplements in the UK (coming third after vitamin D and multi-vitamins), according to a recent survey by The Grocer magazine.

Found mostly in fruit and veg, vitamin C is an antioxidant — i.e. it helps protect our cells from damage, working to neutralise harmful molecules that are a by-product of our metabolism, as well as environmental factors such as pollution.

Vitamin C also helps to maintain our bones, cartilage, skin and blood vessels and plays a key role in wound healing and immunity. Some studies suggest that it may also play a vital role in keeping depression at bay, improving cardiovascular health and slowing down cognitive decline as we age.

A study in the British Journal of Nutrition found people who ate vitamin C-rich kiwis had better improvements in mood, sleep and activity levels than participants who took supplements

Vitamin C is not manufactured or stored by the body so we need to have it daily. But supplements may not be the best way to get it.

A recent study in the British Journal of Nutrition that compared the effects on mood, sleep and activity levels in people given either vitamin C-rich kiwi fruit, supplements or a placebo every day, found those eating the kiwi reported the most improvements in just four days. The people taking supplements experienced only marginal mood improvements up until day 12, when their vitamin C was at an optimal level.

‘Getting your vitamin C from food sources is always better, because you’ll also ingest a raft of other beneficial nutrients such as fibre, vitamins, minerals and plant chemicals that you won’t find in a supplement,’ says dietitian Clare Thornton-Wood, a spokesperson for the British Dietetic Association.

In the UK the recommended daily amount (RDA) for adults is 40mg of vitamin C a day, which you can get from eating a large orange.

This level was set in the 1940s, based on the findings of a UK study which was aimed at establishing the minimum amount of vitamin C a wartime population needed to avoid scurvy.

Some experts believe that the RDA of vitamin C should now be as much as 200mg a day for real health benefits. ‘In the U.S. the RDA is 90mg for men and 75mg for women — significantly more than ours,’ says Nichola Ludlam-Raine, a dietitian and founder of nicsnutrition.com.

‘As it is water-soluble, any excess vitamin C that’s not needed would be removed in urine.’

Taking too much (the NHS says up to 1,000mg a day is unlikely to cause harm) in supplement form can cause stomach pain, diarrhoea and flatulence for some people and has been linked to the development of kidney stones.

It’s not just which foods we eat; how we prepare them matters, too. When a vitamin C-rich food is boiled, for instance, as much as 50 per cent of the vitamin content can be lost, says Nichola Ludlam-Raine.

‘For optimal nutrient retention, choose fresh, frozen or canned produce,’ she adds. This is because frozen and canned fruit and veg are often preserved quickly after harvest — just avoid anything in salty water or sugary syrups.

She adds: ‘Avoid boiling or baking fruit and veg, and use methods that limit contact with heat and water, such as stir-frying or steaming.’

To find the vitamin C you need, use our guide for some of the best — often surprising — sources.

Chestnuts

50g, 13mg vitamin C. 33% of recommended daily amount.

Nuts don’t tend to offer very much vitamin C, but chestnuts are the notable exception.

They are also rich in gallic acid and ellagic acid — two anti-inflammatory compounds that increase in concentration when cooked. Fresh in season, or canned or vacuum-packed versions, can be used in stuffing, sauces or roasted and sprinkled over salads.

Try chestnut flour (which is gluten-free) for baking and thickening soups and stews

Spam Lite

50g, 19.25mg vitamin C. 48% of recommended daily amount.

Vitamin C’s antioxidant properties make it a great preservative, so you will often find generous amounts of it (often labelled as sodium ascorbate) in canned meat products such as Spam and other types of luncheon meat or ham, where it helps maintain the meat’s pink colour and prevents the formation of carcinogenic nitrites.

Red meat is also a good source of protein, but eating too much is linked to bowel cancer, so the NHS recommends that we limit it to 70g red and/or processed meat a day.

Yellow pepper

Half a pepper, 122mg vitamin C. 305% of recommended daily amount.

Bell peppers are one of the richest sources of vitamin C, but the content varies with the colour. Half a green pepper provides around 53mg of vitamin C; half a red pepper, 94mg; half an orange pepper, 105mg — but half a yellow pepper will give you a whopping 122mg of vitamin C, three times your RDA.

It’s also a good source of gut-friendly fibre and vitamin A (for vision). Have as crudités with hummus; or de-seed, fill with rice and bake.

Fresh lemonade

200ml, 17.8mg vitamin C. 45% of recommended daily amount.

Citrus fruit are packed with vitamin C, and their juices offer a concentrated source. The vitamin C content can vary depending on how the fruit has been processed and how long the drink has sat on the shelf.

For the highest vitamin C content, try home-made lemonade (with lemon juice, water and a little sugar), or look for freshly squeezed lemonade in supermarkets and drink within a few days of opening.

The acid and natural sugars in lemon juice can be damaging for teeth, so sip water after it.

Tomato soup

200g bowl, 15.6mg vitamin C. 39% of recommended daily amount.

Tomatoes — tinned or fresh — provide useful amounts of vitamin C. Add roasted red peppers to your own recipe to boost the vitamin C content, and beans or lentils for extra fibre.

The vitamin C from the tomatoes will also help your body absorb the iron in the beans and pulses.

Processed tomatoes are a particularly good source of lycopene, a plant pigment with powerful antioxidant properties, and a bowl of tomato soup will also count as one of your five-a-day.

Mussels

75g, 10mg vitamin C. 25% of recommended daily amount.

It’s rare for protein-rich foods to be a source of vitamin C — but mussels, clams and oysters are exceptions. A 75g serving (a small bowl) of mussels provides 10mg vitamin C, which is higher per gram than some fruit.

Shellfish are also a good source of heart-friendly omega-3 fatty acids and zinc, which is needed for skin health and thought to work with vitamin C to support the immune system.

Baobab powder

2tsp, 26.6mg vitamin C. 67% of recommended daily amount.

This ‘superfood’ — available in large supermarkets — is made from the fruit of the baobab tree, which grows in Africa and Australia.

Studies show baobab has a high vitamin C content and is a good source of bone-strengthening calcium and magnesium, plus iron. The dried baobab fruit is ground into a powder, which is almost 50 per cent gut-friendly fibre.

The citrusy powder can be blended into smoothies, sprinkled over porridge and yoghurt, or stirred into stews and curries.

Cauliflower rice

125g, 50mg vitamin C. 125% of recommended daily amount.

Cruciferous vegetables such as cauliflower, broccoli, sprouts and cabbage are excellent sources of vitamin C.

Cauliflower rice is an easy way to include the veg in meals. Make your own by grating raw florets, or buy ready-made cauliflower rice which is available at most supermarkets.

Saute or steam in a covered pan for five minutes to cook — and serve in place of regular rice or mashed potatoes. A serving is low-calorie and provides 6 per cent of your daily fibre.

Baked red potato 

One potato, 16.6mg vitamin C. 42% of recommended daily amount.

Potatoes that have been peeled before they’re boiled, fried or baked can lose up to 45 per cent of their vitamin C during cooking — unpeeled, baked potatoes lose around 7 per cent. Just make sure you eat the skin to get as much vitamin C as possible.

The skin of some potatoes, especially those with brightly coloured red or purple skins, has been found to contain up to 12 times more antioxidant nutrients such as vitamin C than the flesh.

Mango sorbet

125g, 19.25mg vitamin C. 49% of recommended daily amount.

Freezing has been shown to be an efficient way to preserve the vitamin C levels in fruit and vegetables — a fresh fruit sorbet or fruit puree lolly can make a useful contribution towards your daily vitamin C intake — and counts towards your five-a-day.

Look for citrus fruit, mangoes and berries, which are all particularly good sources of vitamin C.

Because the fruit is pureed or juiced — and often has sugar added — it’s best to eat them as part of a meal, or keep as an occasional treat.