Value of Eating the Rainbow
Packing as many colours onto your plate as possible isn’t just visually appealing, it’s great for your health too.
Walk through the fresh produce section of the supermarket and you’ll see a dazzling rainbow of colours, from green apples, spinach and celery, to deep purple cabbage and eggplant, red capsicums, strawberries and grapes, to yellow and orange produce like corn, pumpkin and sweet potato. These vibrant hues indicate that a fruit or vegetable is rich in particular vitamins, minerals and phytonutrients (naturally occurring plant chemicals that give plants their colours).
While there aren’t any official guidelines for how many servings of each colour of produce you should eat, your best tactic is to aim for as much variety as possible every day, so that you’re getting a broad spectrum of health-boosting nutrients. Here are some of the stand-out nutrients you’ll get from different coloured produce:
Red & pink
Red and pink fruit and veggies such as tomatoes, watermelon, guava and grapefruit contain lycopene, a potent antioxidant which research links to reduced risk of stroke and prostate cancer.1,2 Red produce such as strawberries, red cabbage and cherries also contain anthocyanins, which may protect against cardiovascular disease and diabetes.3
Orange & yellow
Produce with an orange or yellow hue is packed with beta-carotene, a plant pigment which converts into vitamin A, an important nutrient for good vision, strong immunity and healthy skin.4 Corn in particular is rich in lutein and zeaxanthin, antioxidants which research shows improve vision in people with age-related macular degeneration.5,6
Green fruit and vegetables are coloured by chlorophyll, a phytonutrient which is believed to support detoxification.7 Asparagus, spinach, broccoli, bok choy and peas are all excellent sources of folate, a B vitamin essential for the healthy development of babies in early pregnancy.8 Sufficient folate is also thought to be protective against depression, as people deficient in this nutrient can be at greater risk of the mood disorder.9
Blue & purple
Similar to red produce, blue and purple fruit and vegetables contain anthocyanins, antioxidants which help fight harmful free radicals.10 Blueberries deserve a special mention – new UK research shows the sweet superfood boosts brain activity and improves working memory in older people.11
Brown & white
White, brown and cream-coloured produce such as onions, garlic, cauliflower, mushrooms and potatoes contain anthoxanthins, which can potentially help to reduce blood pressure and control cholesterol.12 Bananas and potatoes are good sources of potassium, needed for proper water and electrolyte balance,13 while garlic is rich in allicin, a natural antibiotic that helps bolster your immunity.14
1. Karppi J, Laukkanen JA, Sivenius J. Serum lycopene decreases the risk of stroke in men: a population-based follow-up study. Neurol 2012:79(15):1540-1547.2. Chen J, Song Y, Zhang L. Lycopene/tomato consumption and the risk of prostate cancer: a systematic review and meta-analysis of prospective studies. J Nutr Sci Vitaminol (Tokyo) 2013;59(3):213-223.
3. Beverley J. Anthocyanins. Current Biol 2012;22(5):157-150.
4. University of Maryland Medical Centre. Beta-carotene, last reviewed 2015. Viewed 27 Apr 2017, http://www.umm.edu/health/medical/altmed/supplement/betacarotene
5. Abdel-Aal EM, Akhtar H, Zaheer K. Dietary Sources of Lutein and Zeaxanthin Carotenoids and Their Role in Eye Health. Nutrients. 2013;5(4):1169–1185.
6. . Liu R, Wang T, Zhang B. Lutein and Zeaxanthin Supplementation and Association With Visual Function in Age-Related Macular Degeneration. Investigative Ophthalmology & Visual Science 2015;56: 252-258.
7. Chlorophyll and Chlorophyllin. Linus Pauling Institute 2009. Viewed 27 Apr 2017, http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/chlorophyll-chlorophyllin
8. FSANZ. Folate and pregnancy 2016. Viewed 27 Apr 2017, http://www.foodstandards.gov.au/consumer/generalissues/pregnancy/folic/Pages/default.aspx
9. Coppen A, Bolander-Gouaille C. Treatment of depression: time to consider folic acid and vitamin B12. J Psychopharmacol 2005;19(1):59-65.
10. Konczak I, Zhang W. Anthocyanins—More Than Nature's Colours. J Biomed Biotechnol 2004;2004(5):239–240.
11. Bowtell JL, Aboo-Bakkar Z, Conway M. Enhanced task related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation. Applied Physiology, Nutrition, and Metabolism 2017, 10.1139/apnm-2016-0550.
12. Clemson University. Use Colour to Guide Healthy Food Choices. Viewed 27 Apr 2017, https://www.clemson.edu/extension/hgic/hot_topics/2016/pdf/03%20use_color_to_guide_healthy_food_choices_2%20col.pdf
13. Queensland Government. Give Coour a Spin. Viewed 27 Apr 2017, http://healthier.qld.gov.au/about/give-colour-a-spin/
14. Borlinghaus J, Albrecht F, Gruhlke MCH. Allicin: Chemistry and Biological Properties. Molecules 2014;19:12591-12618.