Across the ancient continents, throughout the eons, the plant species that managed to get their seeds to favorable soil have been the ones to survive. Vividly colored fruits and vegetables served this function well, providing nourishment for the animals and humans attracted by rich hues and ripening aromas. The seeds within these plants often remained undigested, passing intact through the digestive tract and finding a fertile home some distance from the parent plant, where competition for nutrients might have been less intense.
Humans are attracted to plant pigments at the deepest level. Biology compelled our earliest ancestors to seek out the rich variety of nutrients, energy-rich sugars and pharmacologically active compounds in colorful fruits and vegetables. An intersection of evolutionary paths crisscrossed this ancient past: Well-nourished animals with a keen eye for energy-rich, nourishing foods were more likely to reproduce successfully. Likewise, plants with successful, efficient means of seed dispersal achieved the same, all-important end: passage of genetic material into successive generations.
From these ancient beginnings, human societies have maintained their deep associations with Kingdom Plantae. Artistic expression, religious devotions, seasonal celebrations — many of our human endeavors have included and even exalted the rich variety of glistening color in nature’s edible harvest. Today, scientific research is formalizing what wise people have known for millennia: Botanical pigments hold a complex blend of attractions for human beings. Indeed, vivid coloration suggests more than deliciously ripe fruit: Deeply pigmented varieties often possess medicinal actions that help our body systems work well and avoid disease.
Today, a wealth of new research is revealing the health benefits of the colorful and abundant carotenoids, a diverse group of fat-soluble pigments found in nutritional superstars like broccoli, spinach, carrots and tomatoes. Along with fiber, valuable trace minerals and essential vitamins, carotenoid-rich produce offers an array of protective benefits. An abundance of newly published data suggests that carotenoids confer cardiac and prostate protection, maintenance of eye health, potent antioxidant support and even potential anticancer effects — even more reasons to ensure that your daily ration (many practitioners are now suggesting at least nine servings daily) of fresh fruits and veggies includes a variety of deeply colored selections.
A family of orange-red pigments most commonly associated with carrots (hence, the name), carotenoids and other plant pigments act much like the color filters used in photography — absorbing certain wavelengths of light energy and reflecting others. This selective filtering mechanism allows carotenoid pigments to absorb and trap visible light energy at the shorter wavelengths of the blue and green portions of the spectrum. The longer wavelengths of red, orange and yellow light are reflected, producing the brilliant hues of the carotene-rich plants — tomatoes, carrots, peppers and squashes. (In green vegetables, the red-yellow of carotene is often masked by the green of chlorophyll. Typically, the more deeply colored green and yellow the fruits and vegetables are, the more carotene they contain.) This capacity to absorb light energy has important implications in inhibiting free radicals and protecting us from sun-induced aging and skin damage.
In a study published in the September 2004 issue of Free Radical Biology and Medicine, researchers reported that beta-carotene confers protection against MMPs — chemical mediators involved in skin damage and aging due to sun exposure. Antioxidant activity is key to this protection, as beta-carotene neutralizes the harmful effects of unpaired electrons, commonly referred to as free radicals, a reference to their highly reactive and destructive nature. By donating electrons as needed, beta-carotene neutralizes the reactive properties of free radicals and offers some protection against sun-related skin damage.
Deeply colored produce possesses medicinal actions that help our bodies avoid disease.
While the myriad benefits of beta-carotene have been known for some time, the healthful effects of other carotenoids are just beginning to emerge. Sponsored by the National Eye Institute (a division of the federal government’s National Institutes of Health), the Age-Related Eye Disease Study (AREDS) is a landmark 10-year clinical study that proved the benefit of carotenoid supplements for individuals at risk for certain eye diseases.
In response to these findings, a number of nonprescription vitamin and mineral supplements have been reformulated to include lutein, an abundant carotenoid found in leafy green vegetables, red grapes, kiwis, egg yolks and corn. Findings from the AREDS trial suggest that diets rich in lutein may help reduce the risk of certain types of eye diseases, including macular degeneration, the foremost cause of vision loss in the elderly. Along with zeaxanthin (another carotenoid pigment found in abundance in orange peppers), lutein concentrates in the macular segment of the retina, the pigmented part of the eye that is responsible for central vision. Scientists suspect that it is the high concentration of carotenoids here that confers protection by absorbing harmful wavelengths from the sun’s rays and by neutralizing free radicals.
The roles of lutein and zeaxanthin in eye health received extensive scrutiny in 2004. A number of studies found significant improvements in visual acuity and other measures of overall quality of vision. Greater improvement was seen with formulations that include a mix of other vitamins and minerals, including zinc and vitamins A, C and E. And while many of these studies confirmed the protective benefits of lutein and zeaxanthin supplements for individuals who already had some macular degeneration, two important Harvard studies confirmed a protective benefit based on dietary intake from fruits and vegetables. The Physicians’ and the Nurses’ Health Studies, conducted by researchers at the Harvard School of Public Health and the University of Massachusetts, respectively, were multiyear trials designed to evaluate the relationship between dietary intake of carotenoids and the development of cataracts severe enough to require surgical extraction. Both studies, published in the American Journal of Clinical Nutrition in 1999, reported that individuals with the highest intakes of lutein and zeaxanthin had diminished risks of cataract extraction — a 22 percent lower risk for the women and a 19 percent lower risk for the men, suggesting that diets high in these pigments may decrease the development of severe cataracts.
You also may have noticed that your favorite multivitamin now boasts the power of lycopene, the primary red carotenoid found in tomato products, including ketchup and tomato juice, as well as several red-fleshed fruits, such as grapefruit and watermelon. Evidence suggests that lycopene might protect the heart by reducing the incidence of stroke and heart attack, as well as certain other cardiovascular risk factors in people with higher tissue concentrations of the carotenoid. Lycopene is a potent antioxidant, but new research suggests lycopene may diminish cholesterol production in the body, enhance cellular communication and inhibit inflammatory processes.
In addition to promoting a healthy cardiovascular system, lycopene may offer a dual benefit. Research suggests that diets rich in lycopene help maintain healthy prostate tissue. Compelling evidence has accumulated over the past decade as numerous studies have revealed the strong association between dietary consumption of lycopene-rich foods and a decreased risk of prostate cancer. Researchers note that higher blood levels of lycopene correlate with lower levels of the chemical markers that accompany prostate cancer. Lycopene also has strongly protective effects against lung and stomach cancers. Promising benefits also have been noted in preventing cancers of the pancreas, colon, rectum, esophagus, oral cavity, breast and cervix.
For those of us hoping to prevent age-related eye disease, cardiovascular disease, obesity and cancer, it is certainly advisable to incorporate more deeply colored produce into our daily diets, and the jewel-toned berries of spring and summer are superb sources. Berries are rich in anthocyanins, a group of botanical pigments that impart the brilliant reds, blues and purples to many flowers and fruits. Low in sugar and packed with important trace minerals, anthocyanin-rich fruits are tiny powerhouses of medicinal and nutritional support.
Traditional therapies have made use of berries’ diverse spectrum of activity — including laxative, astringent, anti-inflammatory and expectorant actions. Elderberry was used as a restorative cordial, buckthorn berry to relieve constipation. Bilberry extracts are an accepted German plant medicine for relief of sore throat and mild inflammation of the oral mucosa, and cranberry is a time-honored choice for natural support of urinary tract health. (It was previously thought that cranberry acidified the urine, contributing to the inhibition of bacteria. Research now suggests that a novel antibacterial action is at work, whereby bacterial attachment to tissues of the urinary tract is suppressed, thus preventing the development of infection.)
Since popularization of the widely heralded “French Paradox” (the suggestion that red wine may offer some protection against coronary artery disease), interest in the health benefits of the anthocyanin-rich fruits has heightened. Their potent antioxidant properties offer enormous potential in areas of disease prevention and treatment, and a wealth of new research is uncovering promise in a variety of areas, including tumor suppression; antimicrobial actions; prevention of hypertension, cardiac enlargement, atherosclerosis and gastric ulcers; and protection against large bowel cancer, cataracts and diabetes.
If you’re looking for potential insurance against the development of chronic disease, obesity and cancer, indulge in the season’s best selections of deeply colored fruits and vegetables. The abundant, fresh offerings of spring and summer make this an ideal time to begin enjoying more of these superfoods. Feast on Middle Eastern tomato salad (see recipe below) with grilled corn on the cob and mixed berries for dessert. You’ll savor the best of the season’s fresh offerings, plus ensure a healthy mix of disease-fighting pigments. Additionally, you’ll be sure to benefit from the full complement of fiber, trace minerals and vitamins that are present in whole foods.
Check with your health-care provider about the suitability of eye vitamins, or check out one of the daily multivitamin combinations with added carotenoids. One quick word of caution: While smokers are strongly encouraged to consume a healthy diet that is rich in fresh produce, some studies have suggested the potential for increased cancer rates and other adverse effects with the use of high-dose beta-carotene products by individuals who smoke. For this reason, smokers should consult their health-care provider before using products with high levels of beta-carotene.
A graduate of the University of Texas, Kathy Azmeh-Scanlan is a registered pharmacist in community practice. She lives in Austin, Texas, with her husband, Kevin, and their son, Joseph.
The reference list for this article is extensive. If you would like a copy, please send a self-addressed, stamped envelope to “Plant Pigments” Herbs for Health, 1503 SW 42nd St., Topeka, KS 66609; or e-mail us at editor@HerbsForHealth.com.
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