You may have previously heard the recommendation to ‘eat the rainbow’ but why is important to include all the varying colors in the diet? Compounds called phytochemicals that are naturally occurring in fruits and vegetables determine their color. Phytochemicals are not required for intake in the diet but provide vast benefits beyond those that essential nutrients give. These substances work in synergy with the elements like vitamins, minerals, and fiber that are found in plants to promote health and decrease risk for disease. Thousands of these substances have been identified and while it is not clear exactly how phytochemicals work or which combinations may offer the greatest benefit, by eating a colorful diet you can ensure that you’re obtaining a wide variety of various phytochemicals.
Although many plants contain multiple phytochemical and research is ongoing as to which colors impact health in what way, foods may be classified into several broad color categories based on their phytochemical makeup.
Blue/Purple/Red: The phytochemical anthocyanin is primarily responsible for the blue and purple hues found in produce. Some anthocyanin rich foods may have a reddish/pink hue as well. The anthocyanin phytochemical is beneficial in clot formation, blood, pressure, and heart health as well as memory and brain health. Select fruits or vegetables with the deepest hues to obtain the most anthocyanin. Examples of anthocyanin containing foods include blueberries, blackberries, purple grapes, red cabbage, beetroot, pomegranate, raspberries, cranberries, plums, and eggplant.
Green: The plant pigment chlorophyll provides the green color to many plants. Green foods are also high in the phytochemicals known as isothiocyanates. These phytochemical types are beneficial to liver health and assist it in removing toxic and carcinogenic compounds. For this reason, foods rich in green may be particularly anti-cancerous. Green foods rich in isothiocyanates include broccoli, cabbage, bok-choy, and Brussels sprouts.
Green/Yellow: The phytochemical lutein is found in many other green vegetables. Lutein is beneficial for eye health and may protect against age related macular degeneration. Indoles and saponins are additional anti-cancerous phytochemical compounds found in green produce. Examples include green leafy vegetables, avocado, the skin if pistachios, and kiwifruit.
Yellow/Orange: Beta-cryptooxanthin and beta-carotene are the predominant types of phytochemicals found in yellow and orange plant foods. Beta-carotene can be converted into the antioxidant vitamin A by the body. Vitamin A is important for vision and is has anti-inflammatory properties. These phytochemicals can also assist in prevention of certain cancers and may improve immune function. Fruits and vegetable fitting into this category include carrot, sweet potato, mango, peach, lemon, orange, grapefruit, squash, corn, pineapple, and apricot.
Red: The phytochemical lycopene is found in high concentrations in red fruits and vegetables. Lycopene is another antioxidant and can reduce risk for various cancers as well as promote heart health. Tomatoes, guava, and watermelon are examples of lycopene containing foods.
White: Although white is not a color in the rainbow it should most definitely be one on your rainbow plate. Some white produce is particularly high in the phytochemical allicin. Allicin is know for its antiviral and antibacterial properties and may support immune health. Allicin is found in garlic, onion, shallots, and leeks.
Phytochemical nutrition research is complicated and deep diving. However, the good news on this complicated subject matter is that if you are uninterested in learning the ins and outs of various colors and their properties the strategy towards health is the same: eat your rainbow!