November 2008 Issue

Color Me Healthy — Eating for a Rainbow of Benefits
By Juliann Schaeffer
Today’s Dietitian
Vol. 10 No. 11 P. 34

Got the blues? Not your mood, your food! While you’re at it, make sure you also have reds, yellows, and other bright colors on your plate.

Beige may be a mainstay in many wardrobes because of its versatility, but when it relates to diet, simply beige is all the rage for all the wrong reasons. Americans’ affinity for all that is quick, cheap, and convenient is directing many to the cracker, cereal, and cookie aisles, leading to a high-fat and highly processed “beige diet” that is nutrient impaired.

According to Susan Bowerman, MS, RD, CSSD, a lecturer in the department of food science and nutrition at Cal Poly San Luis Obispo and coauthor of What Color Is Your Diet? a purely beige diet may fill Americans up now, but it could cost them later.

“We eat foods primarily based on their taste, their cost, and how convenient they are,” she notes. “The food manufacturers have done a great job of creating many foods that are easy to eat, inexpensive, and rich in sugar, fat, and salt so that they taste good. Starches, fats, and sweets are the least expensive foods in the diet, so it’s easy to see why we lean toward these ‘brown/beige’ foods. They fill us up for very little monetary cost, but there are significant health costs to a diet that is so high in refined carbohydrates and devoid of the vitamins, minerals, fiber, and phytochemicals that are so abundant in plant foods.”

Americans’ fondness for foods lacking color also reflects a metaphor of what else is lacking in processed foods: phytochemicals. While some processed foods may reincorporate key nutrients during processing, “Many of the flavonoids, tannins, etc are not replaced during processing,” says Susan Kasik-Miller, MS, RD, CNSC, a clinical dietitian at Sacred Heart Hospital in Eau Claire, Wis. “The metaphor also holds for the look of our diet. Literature references bland beige swill as the only food offered to suffering people. A colorful, balanced diet is associated with good health and prosperity.”

Phytochemical-Filled Produce
So what does color have to do with diet anyway? One word: phytochemicals. These substances occur naturally only in plants and may provide health benefits beyond those that essential nutrients provide. Color, such as what makes a blueberry so blue, can indicate some of these substances, which are thought to work synergistically with vitamins, minerals, and fiber (all present in fruits and vegetables) in whole foods to promote good health and lower disease risk.
 
According to information from the Produce for Better Health Foundation (PBH), phytochemicals may act as antioxidants, protect and regenerate essential nutrients, and/or work to deactivate cancer-causing substances. And while research has not yet determined exactly how these substances work together or which combination offers specific benefits, including a rainbow of colored foods in a diet plan ensures a variety of those nutrients and phytochemicals.

“Plant products are sources for phytochemicals of which there are thousands that have been identified,” explains Kasik-Miller. “These chemicals are known to have disease-preventing properties, but the color of a food does not necessarily mean it contains one particular phytochemical class. Foods contain multiple phytochemicals, as well as vitamins and minerals, and it is not known how many other phytochemicals await to be identified and what functions they have with health.”

Kathy Hoy, EdD, RD, nutrition research manager for the PBH, says eating a variety of foods helps ensure the intake of an assortment of nutrients and other healthful substances in food, such as phytochemicals, noting that color can be a helpful guide for consumers. “Nutrients and phytochemicals appear to work synergistically, so maintaining a varied, colorful diet with healthful whole foods is a pragmatic approach to optimal nutrition.”
 
And since the average American is eating less than five servings per day of their peas, carrots, and cantaloupe, when it should be upward of seven to 13 servings for most adults, many consumers could be unknowingly missing out on a gold mine of disease prevention.1 It turns out that having clients count colors instead of calories may be an easier fix for not only weight control but overall wellness.

Counting Colors
In What Color Is Your Diet? David Heber, MD, PhD, and Bowerman attempted to group foods according to their predominant phytochemical group, coding plant foods into seven color categories: red, red/purple, orange, orange/yellow, yellow/green, green, and white/green. While research regarding color’s effect on health is ongoing and often opaque, the following is a summary of produce’s relationship with the rainbow.

Blue/Purple
Behind the color: The blue/purple hues in foods are due primarily to their anthocyanin content. Guide clients toward darker selections, as the darker the blue hue, the higher the phytochemical concentration. “In our book, we called these foods red/purple because many of the foods that are rich in anthocyanins also have a red or pink hue,” says Bowerman. Anthocyanins are antioxidants that Bowerman says are particularly heart healthy and may help support healthy blood pressure.

Gloria Tsang, RD, editor-in-chief of HealthCastle.com, says, “The anthocyanins that give these fruits their distinctive colors may help ward off heart disease by preventing clot formation. They may also help lower risk of cancer.”

And the color’s richness is actually one sign that the food is ripe and ready to eat, notes Kasik-Miller, adding that blueberries are considered to have the highest antioxidant activity of all foods.

Examples: Eggplant (especially the skin), blueberries, blackberries, prunes, plums, pomegranates

Green
Behind the color: The natural plant pigment chlorophyll colors green fruits and vegetables. “In our system, the green foods represented those foods rich in isothiocyanates, which induce enzymes in the liver that assist the body in removing potentially carcinogenic compounds,” says Bowerman. According to information from the PBH, cruciferous veggies such as broccoli and cabbage contain the phytochemicals indoles and isothiocyanates, which may have anticancer properties.

“Green vegetables are excellent sources of vitamin K, folic acid, potassium, as well as carotenoids and omega-3 fatty acids,” adds Kasik-Miller. “Folic acid is needed to prevent neural tube defects during pregnancy, and vitamin K is essential in blood clot formation. Diets high in potassium are associated with lowering blood pressure, and there is an inverse relationship between cruciferous vegetables and cancer, especially colon and bladder cancers.”

“In addition, sulforaphane, a phytochemical present in cruciferous vegetables, was found to detoxify cancer-causing chemicals before they do damage to the body,” says Tsang.

Examples: Broccoli, cabbage, bok choy, Brussels sprouts

Yellow/Green
Behind the color: A variation of the green color category, these foods exhibit a richness in lutein, says Bowerman. “Lutein is particularly beneficial for eye health,” she says. “There are lutein receptors in the macula of the eye, and lutein helps protect against age-related macular degeneration.” For a somewhat surprising source, have clients check out pistachio nuts—there is lutein in the green skin around the nut.

Another reason to grab some yellow/green kiwifruit at the grocery store, says Kasik-Miller, is its high amount of vitamin C.

Examples: Avocado, kiwifruit, spinach and other leafy greens, pistachios

Red
Behind the color: Lycopene is the predominant pigment in reddish fruits and veggies, according to Bowerman. A carotenoid, lycopene is a powerful antioxidant that has been associated with a reduced risk of some cancers, especially prostate cancer, and protection against heart attacks. Look for tomato-based products for the most concentrated source of this phytochemical.

“Tomatoes help support the health of prostate and breast tissue,” adds Bowerman.

And although some nutrients, such as vitamin C, are diminished with the introduction of heat, Hoy says, “The benefits of eating produce are not dependent on eating raw foods. In fact, cooking enhances the activity of some phytochemicals, such as lycopene. Obtaining optimal benefit from the nutrients in food, especially produce, depends on proper selection, storage, and cooking of the produce.”

Cooked tomato sauces are associated with greater health benefits compared with the uncooked version because the heating process allows all carotenoids, including lycopene, to be more easily absorbed by the body, according to information from the PBH.

“In addition to vitamin C and folate, red fruits and vegetables are also sources of flavonoids, which reduce inflammation and have antioxidant properties. Cranberries, another red fruit [whose color is due to anthocyanins, not lycopene], are also a good source of tannins, which prevent bacteria from attaching to cells,” says Kasik-Miller of more reasons to relish red.

Examples: Tomatoes and tomato products, watermelon, pink grapefruit, guava, cranberries

Yellow/Orange
Behind the color: “We had an orange/yellow group representing beta-cryptoxanthin and vitamin C,” says Bowerman. “Our orange group foods are also rich in beta-carotene, which are particularly good antioxidants.”

Beta-cryptoxanthin, beta-carotene, and alpha-carotene are all orange-friendly carotenoids and can be converted in the body to vitamin A, a nutrient integral for vision and immune function, as well as skin and bone health, according to information from the PBH.

“These foods are commonly considered the eyesight foods because they contain vitamin A. Beta-carotene, which can be converted into vitamin A, is a component of these foods as well. In addition, they may have high levels of vitamin C, and some contain omega-3 fatty acids,” says Kasik-Miller.

Since eyesight is dependent on the presence of vitamin A, Kasik-Miller notes that it is considered the “vision vitamin.” “Other [phyto]chemicals typically found in yellow/orange fruits and vegetables protect our eyes from cataracts and have anti-inflammatory properties. They also help with blood sugar regulation,” she adds.

Tsang notes that the beta-carotenes in some orange fruits and vegetables may also play a part in preventing cancer, particularly of the lung, esophagus, and stomach. “They may also reduce the risk of heart disease and improve immune function,” she says.

Examples: Carrots, mangos, cantaloupe, winter squash, sweet potatoes, pumpkins, apricots

No Color? No Problem
While color can give clients a general idea about what lies beneath eggplant’s exterior, a food’s hue does not tell all, and it is certainly not an exclusive indicator of phytochemical content. While some phytochemicals are pigments that give color, others are colorless.

“The largest class of phytochemicals are the flavonoids, which for the most part are colorless,” explains Bowerman. “Flavonoids are powerful antioxidants, and these help the body to counteract free-radical formation. When free-radical damage goes unchecked, it can cause significant damage to body cells and tissues.”
 
There are more than 4,000 different flavonoids, and according to information from the PBH, they are classified into the following categories:

• flavonols:
            -myricetin (in berries, grapes, parsley, and spinach);
            -quercetin (in onions, apples, broccoli, cranberries, and grapes);

• flavones:
            -apigenin (in celery, lettuce, and parsley);
            -luteolin (in beets, bell peppers, and Brussels sprouts);

• flavanones:
            -hesperetin and naringenin (both in citrus fruits and juices);

• flavan-3-ols:
            -catechin (in tea, red wine, and dark chocolate);
            -epicatechin, gallate, epigallocatechin, and epigallocatechin gallate (in teas, fruits, and legumes); and

• anthocyanidins (in blue/purple and red fruits and vegetables).

Although not enough research has been conducted to definitively match specific phytochemicals with particular benefits, researchers are currently investigating flavonoids’ effect on lowering the risk of cardiovascular disease and several types of cancer and their role in promoting lung health and protecting against asthma.

Eat Your Colors
The concept of suggesting that clients eat a certain color ratio of foods may be premature, but Hoy says the take-away message is that including a variety of colors in one’s diet seems to equal better overall health, especially in relation to produce. “Epidemiological research suggests that food patterns that include fruits and vegetables are associated with lower risk for some diseases, and a recent article suggested that more variety in fruit and vegetable intake was associated with a lower risk for pharyngeal and laryngeal cancers, suggesting that variety may also be another important factor to consider. However, it is not known if there is an optimal ratio of colors to be consumed or what that is,” says Hoy.2,3

Kasik-Miller agrees: “At this time, scientists are not sure what proportion of phytochemicals is the right balance for disease prevention. There have been studies where specific antioxidants were given and there was an increase in the disease rate. To make recommendations to eat a specific number of servings of beets or blueberries is premature; eat what looks good and you can afford. Foods of the same color do not necessarily contain the same vitamins, minerals, or phytochemicals, so recommendations to eat specific amounts of colored foods is impossible.”

And considering that the majority of individuals are not meeting current recommendations for fruit and vegetable intake, encouraging consumers to use color as a guide for increasing produce consumption is a good strategy, Hoy says.1

What’s the best way to convey this message to clients? Instead of delving into a complex and complicated conversation about phytochemicals, Molly Morgan, RD, CDN, owner of Creative Nutrition Solutions, says the more matters idea can easily be tweaked to more color matters. “I believe consumers can do better by consciously trying to include many different colors in their eating plan rather than getting stuck on what colors do what. Each color provides various health benefits and no one color is superior to another, which is why I believe a balance of all colors is most important,” she says.

“I think the color approach that we used in What Color Is Your Diet? resonated well with people because intuitively they knew that colors equal health and that the more colors that were eaten, the better it probably was to overall health,” says Bowerman of getting this message out to the masses. “Educating people as to the health benefits is a start, but they also have to be willing to try new foods or new varieties of foods—or maybe to prepare unfamiliar foods in a way that will make them taste good—so that they will be willing to add more plant foods to their diet.”

Once people are aware of this dietary color concept, Hoy says creativity can go a long way. “Creatively including fruits and vegetables at meals will help them to include a wide range of different foods. In addition to simple things like adding fruits or vegetables to casseroles, cereal, or sandwiches, being open to trying new foods, recipes, or meal patterns will help to increase variety,” she says. “Other ways to increase variety would include making fruits and vegetables more center of the plate when planning meals, including a fruit and/or vegetable at every eating occasion, adding an extra fruit and/or vegetable side dish to meals, and substituting fruits, vegetables, and beans for other ingredients such as meat in recipes.”

Planning ahead is Morgan’s mantra, and she recommends challenging clients to take notice of color when grocery shopping. She says to tell clients, “Challenge yourself to look at your cart when leaving the produce section, and if you have all red items, head back and swap something out for another color. For example, if you had strawberries, watermelon, and tomatoes, swap the strawberries for some oranges.”

And since winter is fast approaching and the season is swinging away from some of the colorful foods familiar to consumers, such as blueberries and strawberries, Kasik-Miller says a trip to the farmers’ market may be warranted. “Also, people need to get into the habit of cooking at home,” she says. “If you are not sure about what to do with a colorful food or are looking for a new way to eat it, go to the grower’s association Web site to get recipes and new ways to eat foods. I think people need to be more creative with how they prepare foods. People know they need lots of color in their diet but find it hard to change food habits. They need to make small changes over a period of time to achieve success.”
While there may not be much to compare between dinner and Dior, it seems this much is true: There appears to be more reason to eat the spectrum of colors than to wear them.

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