Over the last decade the phrase “eat the rainbow” has crept into public consciousness. It’s even being bandied about in the mainstream media. But what exactly does it mean? Is it based on sound scientific evidence? And how practical is it? Particularly in the middle of winter!
“Eating the rainbow” means eating as wide a range of different coloured fruit and vegetables as possible every day. It does not mean eating a load of bright, artificially coloured snacks and sweets!
We need to eat fruit and vegetables because they contain a lot of really fantastic nutrients. Top of the list is fibre, which helps us feel fuller for longer, helps our gut move things through towards the exit and feeds the microbiome, the vast colonies of microorganisms that inhabit our gut and are essential to our health and wellbeing. They also contain loads of vitamins and minerals which we need for every aspect of our health and wellbeing. And last – but by no means least – they contain magical substances called phytonutrients (phyto = of plants; nutrients … self-explanatory).
Phytonutrients are natural chemicals produced by plants that help to keep them healthy. They give plants their bright colours: the reds, oranges, yellows, greens, blues, and purples – quite literally the rainbow. They help to protect plants from invasion by microorganisms like bacteria and fungi, they provide antioxidant protection against radiation from the sun, they can even deter insects from eating the plants.
Luckily, they don’t deter us from eating them. Because when we eat them, they give us a huge range of health benefits, and every colour has a different positive effect. Although some of the names of phytonutrients may not be familiar (like anthocyanins, glucosinolates and ellagic acid), others like flavonoids, carotenoids, resveratrol, and lutein may be more recognisable.
The colour red in fruit and vegetables is mostly created by carotenoids like lycopene, quercetin, and astaxanthin. They are powerful antioxidants which boost the immune system, support heart health and may reduce the risk of certain cancers 1, 2. Red fruit and veg include tomatoes, strawberries, cherries, radishes, red peppers, watermelon, cranberries and red cabbage. It even included things like red lentils and kidney beans.
The colour orange in fruit and vegetables is also created by carotenoids like alpha carotene, beta carotene, and beta cryptoxanthin. These are also potent antioxidants that act as anti-inflammatories and help to protect the eyes, the brain, and the skin 3, 4, 5. Orange fruit and veg include carrots, pumpkin and squash, sweet potatoes, oranges, peaches, nectarines and some melons.
The colour yellow in fruit and vegetables is created by a range of phytonutrients including flavonoids, rutin, lutein, and zeaxanthin. Yet more antioxidants, these chemicals appear to have a role in helping to prevent or reduce the impact of age-related disease including eye disorders, heart disease, and dementias 6. There is also some evidence that they can support digestive health 7. Yellow fruit and veg include lemons, corn, some squash, yellow peppers, some melons and lemons.
The colour green in fruit and vegetables is created by chlorophyll, flavonoids, isoflavones, and glucosinolates. Once again, the phytonutrients creating the colour are potent antioxidants, protecting cells from damage. And these chemicals also help to support the detoxification processes in the liver 8. Green fruit and veg include cabbage, broccoli, kale, parsley, spinach, green apples and green grapes.
The colours blue and purple in fruit and vegetables are created by anthocyanins, proanthocyanidins, resveratrol, and flavanols. These phytonutrients help to protect against heart disease, help to keep blood pressure at a healthy level and protect against some cancers. They may also help to protect memory function and the ability to concentrate in people of all ages7. Blue and purple fruit and veg include aubergines, blueberries, red and black grapes, beetroot, red cabbage, figs, plums, and blackberries.
And, although white and brown don’t figure in the rainbow, white and brown fruit and veg are also packed with phytonutrients like allicin, flavones and tannins, that provide excellent health benefits. The phytonutrients in white fruit and veg may reduce the risk of stroke, cardiovascular disease and several types of cancer 9, 10. White and brown fruit and veg include apples, pears, mushrooms, cauliflower, garlic, leeks and onions, nuts and seeds, whole grains, parsnips, and potatoes. And the best bit is, because white and brown foods also contain phytonutrients, we don’t need to completely ditch the beige (the colour of comfort food 😊).
So that’s what the rainbow colours in our fruit and vegetables do, and yes, absolutely the benefits noted here are based on sound science. The next question is, how do you do it?
How do I eat the rainbow in the middle of winter?
Admittedly it is more difficult in winter because many of the fruit and vegetables we associate with bright colours are not in season. But there is still plenty of brightly coloured fruit and veg out there – and it doesn’t all need to be fresh. Frozen is fine. So is dried. And tinned. And all of them can be combined into hearty, warming meals. Although there are lots of fresh veg in season through the winter – beetroot, Brussels sprouts, cabbage of all kinds, carrots, cauliflower, celery, chard (including rainbow chard), chicory, kale, kohlrabi (which can be green or purple), leeks, mushrooms, onions (red, white, and brown), parsnips, potatoes, pumpkin and winter squash, turnips and watercress are all available, fresh, and locally grown. There is even some fresh and locally grown fruit around (well, apples and pears…)
Frozen peas, beans, spinach, broad beans, and sweetcorn are great staples to keep in the freezer. You can chuck a handful (or a chunk) into a pasta sauce, a cottage pie, any kind of soup or stew. You can throw in a few dried mushrooms, some red lentils, a tin of chickpeas or kidney beans and there you have a rainbow right there.
Wonky berries are a thing of wonder. And they are a lot cheaper than fresh. In one to the leading UK supermarkets a kilo of frozen berries costs £2.99; the equivalent in fresh berries would cost more than £10 (and go off a lot quicker too!) Make an apple crumble with added frozen wonky berries for desert and your meal will certainly be a rainbow.
You may not be able to eat a rainbow every day, but you might be able to over the course of a week. In discussion with the whole family, I plan meals a week ahead so I know what I need to put on the shopping list. And when I look over those meal plans, although each day may not be overly colourful there is certainly a lot of colour across the week!
1 Mozos, I., Stoian, D., Caraba, A., Malainer, C., Horbańczuk, J. O., & Atanasov, A. G. (2018). Lycopene and Vascular Health. Frontiers in Pharmacology, 9, 521. https://doi.org/10.3389/fphar.2018.00521
2 Rowles, J. L., 3rd, & Erdman, J. W., Jr (2020). Carotenoids and their role in cancer prevention. Biochimica et Biophysica Acta. Molecular and Cell Biology of Lipids, 1865(11), 158613. https://doi.org/10.1016/j.bbalip.2020.158613
3 Mozaffarieh, M., Sacu, S., & Wedrich, A. (2003). The role of the carotenoids, lutein and zeaxanthin, in protecting against age-related macular degeneration: a review based on controversial evidence. Nutrition Journal, 2, 20. https://doi.org/10.1186/1475-2891-2-20
4 Davinelli, S., Ali, S., Solfrizzi, V., Scapagnini, G., & Corbi, G. (2021). Carotenoids and Cognitive Outcomes: A Meta-Analysis of Randomized Intervention Trials. Antioxidants, 10(2), 223. https://doi.org/10.3390/antiox10020223
5 Balić, A., & Mokos, M. (2019). Do We Utilize Our Knowledge of the Skin Protective Effects of Carotenoids Enough?. Antioxidants, 8(8), 259. https://doi.org/10.3390/antiox8080259
6 Tan, B. L., & Norhaizan, M. E. (2019). Carotenoids: How Effective Are They to Prevent Age-Related Diseases?. Molecules, 24(9), 1801. https://doi.org/10.3390/molecules24091801
7 Minich D. M. (2019). A Review of the Science of Colorful, Plant-Based Food and Practical Strategies for “Eating the Rainbow”. Journal of Nutrition and Metabolism, 2019, 2125070. https://doi.org/10.1155/2019/2125070
8 Rose, P., Ong, C. N., & Whiteman, M. (2005). Protective effects of Asian green vegetables against oxidant induced cytotoxicity. World Journal of Gastroenterology, 11(48), 7607–7614. https://doi.org/10.3748/wjg.v11.i48.7607
9 Blumfield, M., Mayr, H., De Vlieger, N., Abbott, K., Starck, C., Fayet-Moore, F., & Marshall, S. (2022). Should We ‘Eat a Rainbow’? An Umbrella Review of the Health Effects of Colorful Bioactive Pigments in Fruits and Vegetables. Molecules, 27(13), 4061. https://doi.org/10.3390/molecules27134061
10 Oude Griep, L. M., Verschuren, W. M., Kromhout, D., Ocké, M. C., & Geleijnse, J. M. (2011). Colors of fruit and vegetables and 10-year incidence of stroke. Stroke, 42(11), 3190–3195. https://doi.org/10.1161/STROKEAHA.110.611152