| Nov 02. 2021 - 12:40PM

Eating the rainbow for health benefits

Emerging phytonutrient research indicates more reasons to eat them – preferably fresh but also as supplements

Dr Celine Aubert

Business Industry Manager

Everyone knows we should eat fruits and vegetables to maintain a healthy and balanced diet. However, most people don’t know about the vast number of studies supporting the correlation between fruits and vegetables and specific health benefits – both physical and mental.

An interesting article about this comes from Deanna M. Minich, PhD, published by The Journal of Nutrition and Metabolism in 2019. It includes a collection of newer studies and calls out several recent findings of the health benefits of plants. Called “A Review of the Science of Colorful, Plant-Based Food and Practical Strategies for “Eating the Rainbow”,” you can find it here.

More health benefits than previously imagined

According to Minich, research points to phytonutrients as being perhaps even more important to our health than the vitamins and minerals we’ve long known are good for us. It’s well documented that phytonutrients are associated with protective, antioxidant activity. New research indicates they can have multiple positive effects on our cell structure and function, causing cells to perform better and keep us healthier. She calls out specifically that phytonutrients play a role in the areas of inflammation, insulin sensitization and stress response.

Due to phytonutrients’ ability to address multiple mechanisms simultaneously, Minich observes they may also be particularly helpful for people with chronic diseases. An example of this is that polyphenols may offer positive benefits for type 2 diabetes, where several dysfunctional processes related to glucose and lipid metabolism are at play.

She also calls out recent research suggesting that some phytonutrients may help buffer one’s susceptibility to disease risks associated with exposure to toxic pollutants in the environment. Several studies also point to the consumption of fruits and vegetables as having a favorable impact on our sense of happiness, life satisfaction and well-being.

Measuring phytonutrient-rich calorie consumption

The USDA (United States Dept. of Agriculture) Nutrient Database now includes food measurements for phytonutrients such as flavonoids, proanthocyanidins, isoflavones and carotenoids. A new term was introduced into the scientific literature in 2004, called the phytochemical index (PI). It is defined as “the percent of dietary calories derived from foods rich in phytochemicals.” Minich refers to several studies since then that indicates a high PI is related to the prevention of weight gain as well as lowered risk of hypertension and breast cancer. Note phytochemical is another term for phytonutrient.

Eating after the rainbow

The thousands of identified phytonutrients and the wide array of health benefits associated with them can be overwhelming. It’s no wonder that so many institutes work to simplify the message to make it easier for consumers to get the great benefits of a healthy diet. In many cases, phytonutrients are also part of what gives fruits and vegetables their beautiful color. For example, curcumin is the pigment that makes turmeric orange and it is also a phytonutrient associated with supporting the immune system and joint health.

An obvious path to simplify the value of eating fruits and vegetables is to associate the colors with health benefits. More than one scientific body recommends eating after a color card and eating two colors in each meal.

Eating after the rainbow is a well-known concept, but anyone who has reviewed more than a couple rainbow graphics could become suspicious since the health benefits associated with the individual colors can vary. That’s because most phytonutrients are associated with multiple health benefits, and it would be impossible to succinctly organize them all. So regardless that health benefits can vary, a color guide is still a good idea.

Below is our color guide of the benefits different colored fruits and vegetables provide from nature’s goodness.


Red foods can not only help reduce the risk of cancer, but also boost your immune system, may confer anti-inflammatory effects and should support brain and heart health. This is due to compounds like anthocyanins and lycopene, which are both naturally colored pigments.

Healthy red foods include tomatoes, red peppers, red onions, radish, red beans, beets, strawberries, raspberries, cranberries, watermelon, rhubarb, red apples, cherries, and pomegranate.

Orange and Yellow

Orange and yellow foods help boost your immune system, should play a role in reproductive health and optimize eye and skin health, due to their compounds like natural carotenoids (alpha or beta carotene, lutein and zeaxanthin) and curcuminoids.

Healthy orange and yellow foods include pumpkin, melon, sweet potatoes, carrots, papayas, cantaloupe, peaches, apricots, tangerines, oranges, lemons, yellow and orange peppers, and spices such as turmeric and saffron.


Green foods are known for their anti-inflammatory properties and are vital for brain, heart, and liver health. They contain compounds like chlorophyll, lutein, zeaxanthin, isothiocyanates and isoflavones.

Healthy green vegetables and fruits include leafy vegetables (spinach, kale, lettuce), asparagus, avocados, green bell peppers, broccoli, brussels sprouts, cucumbers, leafy greens, limes, and zucchini.

Blue and Purple

Blue and purple foods can reduce your risk of cancer, act as anti-inflammatories, and are good for the brain. They contain compounds like anthocyanins and various other polyphenols like betacyanin and resveratrol. Fruits, the darker the better, contain phytochemicals, mainly anthocyanins and other flavonoids that are known to repair damage from stress and inflammation.

Healthy blue and purple foods include blueberries, bilberries, blackcurrants, blackberries, red cabbage, eggplant, grapes, plums, prunes, red beetroot, purple radishes, purple carrots, black olives, and dark cherries.

White and Brown

While not as bright as other colors, white and brown foods still contain helpful phytonutrients which act as anti-inflammatories, support a healthy liver, and optimize hormone health. This is because they contain compounds like allicin, which is a sulfur compound, and tannins, belonging to the family of polyphenolic compounds.

Healthy white foods include garlic, cabbage, onions, leeks, parsnips, white beans (cannellini, lima beans, navy beans, soy-beans), bananas (considered white), lychees, white peaches, and white nectarine. Super brown foods include potatoes, brown lentils, and mushrooms.

Why dietary supplements matter

Getting enough fruits and vegetables to obtain an adequate supply of phytonutrients requires discipline. Minich cites studies stating that particularly men, young adults and people living in poverty fail to consume enough. One study showed that only 9% of American males eat the recommended amount of vegetables. Another study revealed that people who regularly dine out-of-home eat significantly fewer fruits and vegetables than those who dine primarily at home.

Eating a variety of colored fruits and vegetables is the best way to get the different phytonutrients your body needs, and a good rule of thumb is to include two different colors per meal, per day. If this isn’t possible, supplements made with high quality botanical extracts from fruits and vegetables can provide the vital phytonutrients our bodies need.

"New research indicates phytonutrients can have multiple positive effects on our cell structure and function, causing cells to perform better and keep us healthier."