Eat the Rainbow

by Matthew Kadey, MS, RD on Jan 01, 2013

Diet Facts

For better health, pile your plate with colorful fruits and vegetables.

Good nutrition is not a black-and-white issue. In fact, food scientists agree that it’s in our best interest to dine on a rainbow of foods to reap the full spectrum of beneficial antioxidants that Mother Nature provides. That’s because many of the pigments that give fruits and vegetables their dynamic shades are considered phytonutrients, most of which offer numerous health benefits.

Phytonutrients behave as antioxidants, which hunt down and mop up free radicals, preventing them from damaging our cells. The end result of a diet rich in a kaleidoscope of phytonutrients is a lower risk for maladies such as heart disease and cancer. But just as you shouldn’t rely on the same exercises day in and day out for optimal fitness gains, you shouldn’t rely on just a small handful of phytonutrients for disease prevention.

Each individual color in a fruit or vegetable signifies a different set of phytonutrients, each with varied functions. For starters, orange- and yellow-fleshed vegetables such as carrots, butternut squash and sweet potatoes are brimming with beta-carotene, a carotenoid antioxidant that the human body can convert to vitamin A, which helps improve immune, reproductive and bone health (ODS, Medline Plus). Their counterparts in the fruit department, including oranges and mangoes, are brimming with vitamin C, a supercharged antioxidant that can help reduce blood pressure numbers (Juraschek et al 2012). Red-tinged tomatoes, watermelon and pink grapefruit possess the phytonutrient lycopene, which has gained recognition for its anti-cancer efficacy (Sharoni et al. 2012).

More proof that you should grocery shop with vibrant colors on your radar are the sky-high levels of brain-boosting anthocyanin antioxidants found in blue and purple options such as blueberries and plums (Carpentier, Knaus & Suh 2009). Leafy vegetables in the green color scheme such as kale and Swiss chard often deliver healthy amounts of lutein and zeaxanthin, a potent antioxidant duo shown to bolster eye health by diminishing the risk of conditions such as macular degeneration (Kelsey et al 2011). And, finally, don’t underestimate the power of white. For example, mushrooms have compounds thought to boost immune health, while garlic and onions possess allicin—an antioxidant with strong anti-bacterial properties (Kim et al 2012).

When it comes to meal and snack time, the more diversity of cheery colors on your plate or in your bowl, the better. Researchers at Colorado State University found that subjects who ate many different fruits and vegetables experienced lower levels of DNA oxidation, an indication of free-radical damage, than those who ate larger amounts of only a handful of plant foods (Thompson et al. 2006). Further, a 2012 Diabetes Care study found that consuming a greater variety of fruits and vegetables can reduce the risk for developing type 2 diabetes by up to 21% (Cooper 2012). The fiber, vitamins and minerals contained within colorful fruits and vegetables only add to their potency.

On the Bright Side

Ideally, you want to include one or two colorful items with your snacks and at least three different hues of vegetables and fruits with meals. So let this food guide to the rainbow influence your next stroll through the produce aisle.

blue/purple blueberries, blackberries, eggplant, dark plums and prunes, dark grapes, purple cabbage, purple potatoes
red raspberries, strawberries, tomatoes, red bell peppers, radishes, beets, watermelon, red grapefruit, cherries, pomegranates, red-skinned apples
green broccoli, kale, spinach, Swiss chard, arugula, asparagus, watercress, Brussels sprouts, parsley, peas, celery, artichokes, okra, kiwi, avocadoes, honeydew melon
orange/yellow carrots, butternut squash, pumpkin, sweet potatoes, orange or yellow bell peppers, corn, peaches, apricots, mangoes, papayas, oranges, cantaloupes, pineapples
white cauliflower, onions, leeks, garlic, potatoes, mushrooms, rutabagas, parsnip, bananas, jicama


Carpentier, S., Knaus, M., & Suh, M. 2009. Associations between lutein, zeaxanthin, and age-related macular degeneration: an overview. Critical Reviews in Food Science and Nutrition, 49 (4), 313-326.

Cooper, A. J., et al. 2012. A prospective study of the association between quantity and variety of fruit and vegetable intake and incident type 2 diabetes. Diabetes Care, 35 (6), 1,293-1,300.

Juraschek, S.P., et al. 2012. Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition, 95 (5), 1,079-1,088.

Kelsey, N., et al. 2011. Neuroprotective effects of anthocyanins on apoptosis induced by mitochondrial oxidative stress. Nutritional Neuroscience, 14 (6), 249-259.

Kim, Y.S., et al. 2012. Quantitative and qualitative analysis of the antifungal activity of allicin alone and in combination with antifungal drugs. PLoS One, 7 (6), e38242.

Medline Plus. Beta-carotene., retrieved December 7, 2012

ODS (Office of Dietary Supplements). Dietary Supplement Fact Sheet: Vitamin A., retrieved December 7, 2012

Sharoni, Y., et al. 2012. The role of lycopene and its derivatives in the regulation of transcription systems: implications for cancer prevention. American Journal of Clinical Nutrition, 96 (5), 1,173S-1,178S.

Thompson, H. J., et al. 2006. Dietary botanical diversity affects the reduction of oxidative biomarkers in women due to high vegetable and fruit intake. Journal of Nutrition, 136 (8), 2,207-2,212.

IDEA Food and Nutrition Tips, Volume 2, Issue 1

© 2013 by IDEA Health & Fitness Inc. All rights reserved. Reproduction without permission is strictly prohibited.

About the Author

Matthew Kadey, MS, RD IDEA Author/Presenter

Matthew Kadey, MS, RD, is a James Beard Award-winning journalist, Canada-based dietitian, freelance nutrition writer and recipe developer. He has written for dozens of magazines including Runner’s W...


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  • jaclyn forrester

    Agreed Stephen, We should place more emphasis on what types of foods we put in our bodies versus counting every calorie, carb and protein. If everyone would eat a variety of veggies, reduce desserts and drink plenty of water they would fill full faster, increase their energy and improve their health. Great article. -Jaclyn Forrester Founder/ Director of Marketing
    Commented Jan 27, 2013
  • Stephen Cooper

    Simple "rules" like these are so valuable for our clients. No fancy counting of calories, but solid basics often lead to success for our clients. Best, Coop Stephen Cooper Owner/Trainer
    Commented Jan 24, 2013
  • Monika Reineke

    Thanks, to the point with very good information
    Commented Jan 23, 2013

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