Nature’s Color Coding System

What a Vegetable’s Color Tells Us About the Nutrients in It

By Dr. Samar Habib

Centuries ago, in the absence of sophisticated technology and laboratory protocols, human beings still figured out ways to know things about the nutritional value of various foods, the medicinal potential of certain plants and how the body’s metabolic systems worked. In my younger days, I foolishly treated ancient sciences not only as obsolete but also as grossly mistaken. Like any student of most Western institutions of higher learning, I had an unquestioned version of the history of knowledge as having taken a decisive turn in the 17th century, after the Enlightenment. In that version of human history, we lived in a world steeped in error and superstition until the doctrine of materialism came along and explained that there is nothing there other than what we can prove to be true through measurement (quantification) and accurate prediction (repeatability of results).

So, when in my mid-twenties I came across a book about Ayurvedic medicine, I was nothing more than amused when I read about the system of classifying biological dispositions based on fire, water, and wind elements. They also classified foods in accordance with their color and linked these colors to treating imbalances in the humors. If memory serves me correctly, for example, the Ayurvedic practitioner might tell a patient whose body is dominated by the fire element, to eat some bland colored food to counterbalance that overactive humor. They might also ask them to subsist from eating foods that strengthen the already dominant humor, which, in the case of fire (again, if memory serves me correctly) would be red-colored spices, or foods. I thought this was strangely simplistic at the time, but what else would you expect of an ancient system of “knowledge” of the human body? Right? Well, no, I wasn’t right at all. And I didn’t realize I wasn’t right until I began studying Sports Nutrition, to help clients optimize their results in and out of the gym. I am sorry to say that it took a scientist in a white lab coat, standing in front of some beakers and Bunsen burners to tell me that we can garner nutritional information about various vegetables from their color, for me to take seriously the idea of prescribing foods based on color. In that moment, I realized how small my mind had been.

Since that time, I’ve noticed just how many things ancient knowledge got right about the human body and the natural world, because we are only now beginning to corroborate those things with Western science. Things like the effect of contemplating gratitude and forgiveness on the long-term health of the brain, or things like using breathing techniques to manipulate our immune system responses. And who can forget the famous case of a medieval English antibiotic recipe that was replicated in 2015 only to astonish scientists with its ability to destroy antibiotic resistant bacteria! Keep these facts in mind next time you dismiss an idea as superstitious or ridiculous. Make sure you do your research. Maybe that crazy idea from some ancient civilization is not 100% accurate, but much like Western Science, there are plenty of ancient approximations of certain truths that got things right. So, if you’re going to take away anything from this article, it’s that you should keep your mind open.

But, hey, I didn’t lure you over here to give you a lecture about the epistemology of scientific knowledge. I told you that I was going to tell you what the color in different vegetables says about their nutritional value and the essential micronutrients known as phytochemicals that are in them. So, whether you’re just starting out on your journey to better nutrition or you’re a healthy lifestyle veteran, you might want to keep nature’s handy color coding nutritional system under your belt. One thing is for sure, you won’t be able to see vegetables in the same light again.


Purple fruits and vegetables include purple potatoes, purple asparagus, blackcurrants, eggplant, blueberries, blackberries, prunes, grapes and plums among others. They are your go-to soldiers for a healthy heart, brain and bones. They are thought to be helpful in fighting cancer because they remove carcinogens. The phytochemicals they contain are: resveratrol, anthocyanidins, phenolics and flavonoids.

Orange and yellow

Orange and yellow fruits and vegetables are much more commonly consumed by the general population. They include carrots, oranges, mango, pumpkin, sweet potato, pineapple, papaya, peaches, bananas, squash and lemons, among many others. These foods support nervous and immune system functions, as well as promoting eye and vision health. These foods contain the following phytochemicals: Beta-carotene, apha-carotene, beta cryptoxanthin, hesperidin and lutein.


Red fruits and vegetables include rubab, tomatoes, red berries, watermelon, radish and blood oranges. They promote urinary tract and prostate health as well as supporting our DNA molecules. They contain phytochemicals such as hesperidin, quercitin, ellagic acid and lycopene.


Vegetables and fruits are perhaps the most prevalent in traditional diets. They give us a wide array of eating choices, from Kale to broccoli, cucumber to spinach, and kiwi fruit to avocadoes. Green vegetables and fruits contain phytochemicals such as sulphoraphane, isothiocyanates, lutein, EGCG and isoflavones which eliminate carcinogens, build healthy cells and support visual and circulatory systems as well as lung and liver functions. EAT YOUR GREENS!


White fruits and vegetables such as cabbage, onions, mushrooms, garlic, white nectarines and white peaches, support the circulatory system and bone health, while aiding in the removal of carcinogens. They contain the following phytochemicals: glucosinolates, indoles, quercetin, allicin and EGCG.

Obviously, next time you are at a self-serve salad bar, you’ll want to make your salad as colorful as possible. Make it a habit to “eat the rainbow,” as they say.

Dr. Samar Habib is a writer, researcher and scholar. She lives in California. A published author, she also recently published the online course, The Quantum Mind.

Originally published at medium.com

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