Phytochemical against Cancer: Eating in Color

Eating in color means eating a variety of necessary nutrients and minerals.

As this blog looks at the effects of nutrition on gene expression, I have been taught the effects of phytochemicals, which come from plants that we consume. A plant-based diet is important for maintaining health (Heber 165). Substances in fruits and vegetables alone and in combination with one another, have been shown to have specific anticancer effects. In these posts, I will be looking at specific phytochemicals, incorporating them into my diet and lifestyle.

Adding Color to the Diet: (Heber 193-195)

Fruits and vegetables can be classified according to colors - red, red/purple, orange, orange/yellow, green, yellow/green, and white/green according to the specific chemicals that absorb light in the visible spectrum creating the different colors. These chemicals are called phytonutrients or phytochemicals by scientists, where each of these colored compounds works in different ways to protect our genes and our DNA. By making sure we get a representative of each of these seven color-coded groups of the fruits and vegetables every day, it is recommended to eat 5-9 servings of fruits and vegetables every day by various institutions such as the National Cancer Institute.

Eating foods of different colors further ensures that our bodies has what it needs to protect our DNA. Not all fruits and vegetables are the same. The different colors indicate how they differ.

Plant-eating animals naturally use color as an identifying marker of edible plant species. The changing color of ripening fruits and vegetables signify that they are at the peak of their taste and nutritive value. Many of the phytonutrients are actually the pigment molecules that lend ripe fruits and vegetables their distinctive hues.

Carotenoids are chemical compounds that absorb visible light and so determine that carrots are orange, tomatoes are red, and marigolds are yellow. ~700 different carotenoids have been isolated from plants and animals. About 50-60 of these are present in a typical diet. These carotenoids are specifically broken down by the body, often during the process of absorption into the blood stream from the small intestine. They make their way to specific tissues and organs where they have been shown to protect against the type of oxygen damage that can harm your DNA.

Because the color of a plant food can tell us so much about how it supports health, Dr. Heber created a "Color Code System" to help introduce more diversity into the diet. The different colors are important because the different plant chemicals they represent have different effects on the body.

Red Group

• Tomatoes, pink grapefruit, and watermelon containing lycopene 
• Lycopene is more available from cooked tomato products and juices than from whole tomatoes (i.e. liberation of lycopene by breaking the cells down)
• These products are the primary sources of lycopene in our diet
• So, add red as a pasta sauce, tomato soup, tomato juice, and ketchup
• As a practical matter, over 80% of the lycopene in the American diet comes from these tomato products

Red bell peppers contain lycopene, which give them their red hue.

Red/Purple Group

• Grapes, grape juice, prunes, cranberries, blueberries, blackberries, strawberries, and red apples
• Contain anthocyanins, which are powerful antioxidants which may have a beneficial effect on heart disease by inhibiting blood clot formation

Red onions fall into the red-purple group as well as the white/group (discussed bellow).

Orange Group

• Carrots, mangos, apricots, cantaloupes, pumpkin, acorn squash, winter squash, and sweet potatoes
• Provide alpha and beta carotenes
• Fun fact: carrots provide about half the alpha and beta carotene in the US diet, with significant contributions from tomato products

Sweet potatoes fall into the orange group, containing alpha and beta carotenes.

Orange/Yellow Group

• Orange juice, oranges and tangerines, peaches, papaya, and nectarines
• Provide beta-cryptothanxin, a minor carotenoid which accounts for only 0.03 mg of the 6 mg per day intake of all carotenoids by the average American.
• As a practical matter, 87% of cryptothanxin comes from orange juice, oranges, and tangerines
• Other fruits provide smaller amounts, which include peaches, papaya, and nectarines
• These fruits obviously have other benefits and are a separate group primarily to stimulate more diversity in your diet.

Keep in mind that juices can definitely add up in calories and sugars.

Yellow/Green Group

• Spinach, collard, mustard, turnip greens, yellow corn, green peas, avocado, and honeydew melon
• Provide lutein and zeaxanthin
• These carotenoids concentrate in the eye and contribute to eye health
• Lower intakes have been associated with cataracts and age-related macular degeneration, the primary preventable cause of blindness in America

Spinach is one of my favorite in the yellow/green group, providing benefits for eye health.

Green Group

• Broccoli, Brussels sprouts, cabbage, Chinese cabbage or bok choi, and kale
• Contain sulforaphane, isothiocyanate, and indoles that stimulate the genes in our liver to turn on the production of enzymes that break down cancer-causing chemicals in the body

Kale may be bitter at time, but it has versatile uses such as replacement for lettuce and wraps.

White/Green Group

• Garlic, onions, celery, pears, white wine, endive, and chives
• Plants in the onion family contain allicin that has been shown to have anti-tumor effects
• Are also rich sources of flavonoids including quercetin and kaempferol
• Of all the antioxidants in fruits and vegetables, it is the flavonoid which we eat in the largest quantity, up to one gram per day. 

Garlic falls into the white/green group, containing allicin and other wonderful benefits - just be sure to chew some gum afterwards.

Economic Tip of the Day: to save money, buy FROZEN fruits and vegetables, as they are immediately frozen after they are harvested. They are processed very quickly, providing the freshness that we look for in our foods. As a college student, I can speak of the savings that I have made buying frozen; I make sure to boil/steam my veggies once I am ready to use them.

Visually appealing for the eyes, equally delicious for the mouth, and overall good for the body.

Information about adding color to the diet was taken from Dr. Heber's course reader, Winter 2014 (pages have been cited). All photos were taken by me.