Should you eat a rainbow of fruits and vegetables?
Colourful plates of food are appealing, but are they healthy too? Dietitian Annemarie Aburrow explains the health benefits which can come from fruits and vegetables.
Click on the image to see our infographic of the health benefits of different foods (best viewed in Chrome or Firefox web browsers).
Modern chefs consider food presentation an art form, so colourful plates are highly prized. But getting the right proportion of foods from the major food groups is far more important than creating a rainbow.
There’s no evidence that eating a balance of colours leads to a balance in nutritional content, although the natural compounds (phytochemicals) that give fruit and vegetables their colour may be beneficial.
Many of these phytochemicals are antioxidants (natural chemicals that are thought to protect against harmful substances called free radicals), and diets rich in foods that contain these, like fruits and vegetables, are associated with lower levels of cardiovascular disease (CVD).
Eating a variety of foods will help you get essential nutrients and, by doing so, you’ll naturally embrace a broad colour palette. Fruits and vegetables are particularly colourful, so a rainbow plate can help you towards your 5-a-day. Plus, you’re more likely to enjoy eating an attractive meal.
Red
Properties: Contain antioxidants including lycopene (in tomatoes), anthocyanins (red berries, including strawberries), ellagic acid (strawberries, raspberries and pomegranate) and astaxanthin (crab, salmon and prawns).
Health benefits: Lycopene gives red fruits their colour. It is thought to have antioxidant properties that may help protect against CVD and has been reported to help reduce blood pressure and cholesterol.
Lycopene is more easily absorbed in the body when it’s cooked (such as in a homemade tomato sauce). While there is some research to support lycopene’s health benefits, much of it is low quality, so more research is needed. Don’t let that stop you including red fruits and veg in your diet.
As well as the usual vitamins, minerals and fibre that come with all fruits and vegetables, the pop of colour will add interest to everyday dishes. Add pomegranate seeds or cherry tomatoes to a green salad or cous cous or strawberries to a bowl of porridge.
Suggestions: Cherries, cranberries, radishes, red apples, red grapes, red peppers, tomatoes, watermelon.
Top tip: Add chopped tomatoes to omelettes or burritos.
Orange
Properties: High in carotenoids, such as alpha-carotene and beta-carotene.
Health benefits: Beta-carotene gives yellow and orange fruits and vegetables their colour and is converted to vitamin A in the body, where it helps us make hormones and keeps our eyes healthy.
Carrots, butternut squash, pumpkin and sweet potato are all good sources of this vitamin – hence the saying that carrots will help you to see in the dark. In the past, population studies suggested vitamin A (along with vitamins C and E) could help prevent heart attacks.
However, large trials of vitamin A supplementation either alone or in combination with other vitamins haven’t confirmed this. The relationship observed in the original studies may have been a coincidence, or the benefits of consuming nutrients in food may not always be replicated by supplements.
Taking individual supplements should be avoided, unless recommended by your doctor, as it’s easy to consume too much. There is no evidence that eating beta-carotene from foods is harmful, however, so it’s fine to have plenty of orange fruits and vegetables. Citrus fruits like oranges are low in vitamin A but high in vitamin C. Dried apricots are a great source of fibre, iron, potassium and calcium too (but stick to a 30g portion as dried fruits are high in energy).
Suggestions: Cantaloupe melon, mangoes, nectarines, orange peppers, pumpkin, sweet potatoes.
Top tip: Add dried apricot or mango to porridge or cereal.
Yellow
Properties: Contain carotenoids including beta-carotene and beta-cryptoxanthin.
Health benefits: As with orange fruit and vegetables, beta-carotene gives yellow varieties their colour. Foods like sweetcorn, peach, papaya and egg yolk are also rich in the antioxidant beta-cryptoxanthin.
Like beta-carotene, our bodies can convert beta-cryptoxanthin into vitamin A. While some studies have suggested health benefits, such as reducing the risk of rheumatoid arthritis and certain cancers, the evidence is not strong enough for us to recommend specific fruits or vegetables. However, including yellow fruits and vegetables in your diet helps you towards your 5-a-day.
Suggestions: Butternut squash, honeydew melon, lemons, papaya, peaches, persimmons, swede, yellow peppers.
Top tip: Add yellow peppers to chilli, bolognese and salads, or swede to casseroles.
Green
Properties: The pigment chlorophyll gives green fruits and vegetables their colour, but many green vegetables are rich in other nutrients too. Broccoli, cabbage, Brussels sprouts, kale and pak choi are all sources of sulforaphane and glucosinolate.
These vegetables also contain lutein and zeaxanthin, as do peas, sweetcorn, yellow peppers and eggs.
Health benefits: Studies suggest that sulforaphane may help protect against blood-vessel damage and certain cancers. However, most of these studies are based on mice, or human cells in the lab, rather than people.
Further research is needed in humans, including into whether eating broccoli will have the same effect as taking sulforaphane supplements.
We’re currently funding several studies to find out whether sulforaphane could help protect against the damage caused by heart attacks, stroke and gestational diabetes.
There is evidence to suggest lutein and zeaxanthin-rich vegetables, like kale, spinach, broccoli and peas, may help prevent and slow the progression of an eye disease, age-related macular degeneration.
Rather than focusing on a particular fruit or vegetable, aim to increase the total amount of both in your diet, and don’t forget leafy green vegetables.
Suggestions: Apples, asparagus, avocados, celery, courgettes, cucumbers, green grapes, leeks, lettuce, limes, mange tout, sugar snap peas.
Top tip: Stir peas into cooked rice to add colour and nutrients.
Blue / Purple
Properties: Anthocyanins give blue and purple foods their rich colours.
Health benefits: Anthocyanins are powerful antioxidants, which may have a role in protecting cells from damage. However, the positive effects seen in lab studies have not been seen in human studies.
Purple beetroot is rich in nitrates, which may help reduce blood pressure. This conclusion is based partly on research we’ve funded, although we need to do more research in humans.
As well as beetroot, purple lettuce, carrots, green beans, spinach, cabbage and radishes are high in nitrates. Overall, there are many ways that fruit and veg can help reduce your risk of CVD, so it’s best to focus on eating more and a wide variety.
Suggestions: Aubergines, blackberries, blackcurrants, purple grapes, red cabbage.
Top tip: Slice ready-cooked, vacuum-packed beetroot (not pickled or in brine) and add it to salads or toast.
White / Beige
Properties: Anthoxanthins are the pigments that create white or cream colours.
Health benefits: Some studies have suggested that anthoxanthins may reduce the risk of CVD and inflammatory conditions such as arthritis, but there is not enough evidence for us to recommend white fruits and vegetables over those of other colours.
The humble potato – a starchy carbohydrate – gets a lot of bad press, but potatoes are one of the biggest sources of vitamin C in our diets and are full of potassium too. Eat the skins for extra fibre and avoid adding fat when you cook them.
Bananas (which have creamy flesh under that yellow skin), parsnips and mushrooms are also good sources of potassium – an important mineral for normal heart and muscle function.
Suggestions: Bananas, celeriac, garlic, Jerusalem artichokes, mushrooms, onions, turnips, white peaches.
Top tip: Make mash exciting with cooked celeriac or Jerusalem artichokes. Either mash on their own or together with potatoes.
Eatwell guide
As a guide, a third of our diet should be fruits and vegetables, a third starchy carbohydrates (preferably high fibre as wholegrain versions) and the final third lean protein-rich foods (meat, fish, beans, lentils) and reduced-fat dairy products.
Eating small amounts of foods high in fat and sugar is OK too. The Eatwell guide is a tool to help you plan a balanced diet.
The truth about E numbers
Food colourings are added to many manufactured foods. Some are natural, such as curcumin (E100), the yellow substance in the spice turmeric. This is used in some drinks, condiments, confectionery, dairy products, and processed meats and vegetables.
There are also many artificial food colours, such as caramel (E150a-d), which is often added to cola drinks, and tartrazine (E102) – found in fruit squashes, fizzy drinks, instant puddings, custard powder, soups, sauces and ice cream. All food colours go through the rigorous safety assessments of the European Food Safety Authority (EFSA); the assignment of an E number shows they’ve been approved (E stands for Europe).
During this process, an ‘acceptable daily intake’ is established, so the European Commission can decide which foods it can be used in, and in what quantity.