Eat by Colour

Despite the emphasis placed, and information available, on the importance of paying attention to the nutritional content of food and their effect on blood sugar and insulin levels, many people tend to choose foods according to habit and convenience. The surplus of meal planning tools, such as calorie counting, and diet types, such as low carb and low fat diets, can be overwhelming.

Instead of preparing our own food and choosing what is healthy, which is fruits and vegetables, we tend to choose what we are familiar with, which is usually processed and refined snack foods, such as crackers and cookies. Processed meats are also a common choice. What these foods have in common are that they tend to all be beige or dull in colour. Not only do they lack in colour, they tend to lack in key nutrients.

An easier method for choosing foods to create a balanced diet is to use colour as a guide. Fruits and vegetables come in a wide spectrum of vibrant colours, and these hues can be indicators of essential nutrients. There are a multitude of fruits and vegetables available, but they can generally be categorized into a limited number of colours. These categories can include red, white, orange, yellow, green, and blue/purple, and may be divided further into colour variations such as red/purple, white/green and yellow/green.

Foods in the same colour family share similarities in their nutrient profile, even though they may not necessarily contain the exact same vitamins, minerals, or phytochemicals.

Phytochemicals are compounds that occur naturally only in plants. They are considered a “biologically active non-nutrient” since they can affect health, but are not considered essential nutrients. They help protect plants from ultraviolet radiation and pests and are responsible for giving vegetables and fruits their colour, although many phytochemicals are colourless.

Foods may be grouped according to their predominant phytochemical group and resulting colour. Although a food may have a predominant phytochemical group, that does not mean it contains only one particular phytochemical class. Foods are a complex mixture of various compounds and nutrients. Also, the phytochemical content alone does not indicate the exact health benefit of a food.

Three main phytochemicals or pigments found in fruits and vegetables are: chlorophyll, carotenoids, and flavonoids. Flavonoids are a large and diverse group of phytochemicals, and are further divided into subclasses that include flavonols, flavones, flavanones, flavan-3-ols, and anthocyanidins.

White

White foods include garlic, onions, cauliflower, daikon radish, mushrooms, turnip, leeks, ginger, and kohlrabi. These foods tend to get their colour from the pigment anthoxanthins, a type of flavonoid. It plays a role in lowering bad cholesterol, decreasing blood pressure, reducing risk of heart disease and stroke, and reducing inflammation.

White foods also contain sulfur, allicin, and quercetin. Allicin and quercetin are both phytochemicals. Allicin helps lower cholesterol and blood pressure, and quercetin helps support respiratory and cardiovascular health and protect against cancer. Organosulfur compounds can help protect against heart disease and stomach and colorectal cancers.

Major benefits or features of white foods, especially onions and garlic, include boosting the immune system and exhibiting anti-viral, anti-fungal, and anti-inflammatory properties. Cauliflower shares similar nutrient content to other cruciferous vegetables.

Green

The food colour family of green may be further divided into Green/Yellow depending on its hue. Examples of foods in this category are kale, broccoli, spinach, green beans, celery, zucchini, asparagus, parsley, arugula, limes, ocean vegetables (sea vegetables), cucumbers, green apples, avocados, kiwifruit, mustard greens, and chard. They are are predominantly coloured by the natural plant pigment chlorophyll.

Chlorophyll not only plays an important role in the photosynthesis process in plants (the process of using energy from sunlight to produce glucose), it provides a number of health benefits for humans, including acting as a natural blood purifier by improving liver and kidney detoxification, improving digestion, helping control hunger and cravings, promoting the healing process, protecting against cancer, and reducing odour.

Some members of the green colour family, such as spinach, broccoli, collards, and kale, contain lutein and zeaxanthin. Both lutein and zeaxanthin belong to the group of phytochemicals known as carotenoids. They accumulate in the eyes and work together to maintain eye health. They protect the eyes from developing cataracts and age-related macular degeneration.

Cruciferous vegetables may also be good source of folate acid (a B vitamin) and compounds indoles and isothiocyanates. These phytochemicals have been shown to inhibit the development of cancer in several organs and reduce inflammation. Other nutrients common in the green family are fibre, calcium, iron, vitamin K, and potassium. These nutrients are necessary for maintaining proper blood pressure and cardiovascular health, strengthening the muscles and bones, and promoting digestion.

Red

The red colour family consists of foods such as tomatoes, watermelons, beets, red bell peppers, radishes, red chili peppers, red onions, radicchio, pink grapefruit, red grapes, cranberries, raspberries and cherries. Their vibrant colour comes mainly from the pigments lycopene (a carotenoid) and anthocyanins. They are powerful antioxidants that help build healthy cell walls and eliminate free radicals that cause damage.

In addition, they may help protect against diabetes; improve cardiovascular health by preventing atherosclerosis (hardening of the arteries); improve brain health by increasing neuronal signals in the brain centres, mediating memory function, and correcting cell corruption and protecting healthy cells; and prevent cancer by inhibiting the growth of cancer cells.

Other compounds found in red plant foods may include vitamin C and antioxidants ellagic acid and quercetin. Cranberries also contain tannins, which prevent bacteria from attaching to cells, and red grapes contain another antioxidant resveratrol.

Yellow/Orange

Orange and yellow foods may be divided into separate colour families, or combined into one due to the fact that the predominant plant pigment for both colours is carotenoids, in particular alpha- and beta- carotenes. Like other phytochemicals, they are antioxidants that protect cells from oxidative damage caused by free radicals.

Alpha- and beta-carotene, along with beta-cryptoxanthin, are known as provitamin A carotenoids because they can be converted by the body to retinol, an active form of vitamin A. Other carotenoids, including lutein, zeaxanthin, and lycopene, are considered non provitamin A carotenoids because they cannot be converted.

Vitamin A is essential for healthy vision; our eyesight is dependent on its presence. It also plays a role in maintaining healthy skin, bones, neurological function, and immune system. Many foods in the orange and yellow colour families, particularly citrus fruits, are also rich in vitamin C.

Vitamin C helps support healthy immune function; aid in the absorption of iron; reduce exercise-induced oxidative damage; repair and regenerate connective tissue, including bones, blood vessels, and skin; reduce severity of cold symptoms and control allergies by reducing levels of histamine; protect the brain and nervous system from the harmful effects of stress; and maintain cardiovascular health.

Other nutrients found in some of the orange and yellow family foods include folate acid, potassium, beta-cryptoxanthin, and bioflavonoids (also known as flavonoids). Not only do bioflavonoids have antioxidant and anti-inflammatory properties, they help support blood circulation and enhance the action of vitamin C.

Examples of orange and yellow foods include carrots, cantaloupe, sweet potatoes, squash, oranges, tangerines, mangoes, apricots, lemons, pineapple, yellow peppers, grapefruit, yellow beets, yellow winter squash, butternut squash, pumpkin, yellow beets, yellow apples, and star fruit (carambola).

Blue/Purple/Deep Red

Foods in this colour family contain the most antioxidants of all colours. The deep, rich hue of these foods is due to the presence of natural plant pigment anthocyanins. The higher the concentration of the anthocyanins, the darker the colour.

Like other phytochemicals, anthocyanins are powerful antioxidants that protects cells from damage. Foods rich in anthocyanins have long been used for medicinal purposes to treat conditions ranging from hypertension and dysentery to kidney stones and urinary tract infections.

Anthocyanins have anti-inflammatory and antimicrobial properties and have also been shown to increase HDL (“good”) cholesterol and reduce LDL (“bad”) cholesterol, reduce blood pressure, improve eyesight, and suppress proliferation of cancer cells.

This, along with other compounds found in blue, purple, and deep red foods such as antioxidants lutein, zeaxanthin, resveratrol, ellagic acid, and quercetin, as well as fibre and vitamin C, also plays a role in improving eyesight, boosting immune system activity, improving calcium and other mineral absorption, improving memory, increasing circulation, preventing clot formation, increasing urinary-tract and digestive health, and contributing to overall health and disease prevention.

Foods in this family include blueberries, blackberries, eggplant, purple cabbage, purple asparagus, plums, purple grapes, black currants, purple asparagus, and purple carrots.

Many of the foods in different colour families may share similar types of compounds and nutrients. However, these nutrients may come in different quantities. By eating only one type of colour, you can suffer from deficiencies in certain nutrients, and it is by incorporating an array of colours that makes it more likely for you to get all the nutrients you need.

Despite our tendency to consume foods lacking with colour, many of us are drawn to colour, and surround ourselves with it, whether through the colour of our clothing, walls, or accent pieces in our homes. We may add colour to food through the use of artificial colours, but the best way of consuming colours is through the natural, vibrant hues that nature has already given us in our fruits and vegetables.

A simple method of introducing more fruits and vegetables is to follow the rainbow, and add a few extra colours of fruits and/or vegetables to each meal. It is not necessary to memorize the particular benefits of each phytochemical and the nutrient profile of each food colour, though associating certain benefits or nutrients with colours can help you remember them.

The important thing to remember is that the greater the variety of foods and natural colours you eat, the better. Aiming for at least three colours at every meal can help better meet your nutritional needs.

A diet rich in wide variety of colourful fruits and vegetables has been shown to help provide you with more nutrients, prevent against a number of conditions, and improve your overall health. These foods add a splash of colour to your plate, and a multitude of health benefits. Add more colour to your life by adding more colour your meal.