Foods of Color

Foods of Color Clinical Report Summary

Human research shows that certain foods of color and phytonutrient dietary supplements can prevent the development of cancer, heart disease and macular degeneration (1, 2, 3, 4, 7, 8, 9, 10, 11). Scientists believe chemicals from colorful foods called phytonutrients are responsible for much of this health benefit. Foods of color rich in these antioxidant compounds include tomatoes, berries, apples, citrus fruits and leafy greens like spinach, broccoli and kale (1, 2). In order to get the benefit from these nutrients, experts recommend eating a varied diet of colorful fruits and vegetables. But studies show that most Americans are falling short of the 5 serving a day minimum standard (2, 5). Phytonutrient supplements are usually made from the plant's freeze dried fruit or its juice. This supplements, like the colorful fruits and vegetables they are made from, are generally well tolerated with few side effects. People with fruit allergies should be aware as they may also react to phytonutrient supplements.     

Foods of Color Overview

Foods of color is a broad term used to describe foods with deep vibrant colors and intense taste (1, 2). Tomatoes, blueberries, carrots, spinach and kale are some examples of these foods, which are rich in essential vitamins and other organic compounds called phytonutrients (1). Phytonutrients, sometimes called phytochemicals, are antioxidants that give fruits, vegetables and other foods their unique color and taste (1, 2). These pigments and flavors also provide a natural defense system for the plants they inhabit and protect fruits and vegetables from disease and free- radical cell damage. Research finds evidence that some phytonutrients do the same for people (1, 2). There are thousands of phytonutrients and the most common associated with color and flavor include carotenoids like lycopene, which is found in tomatoes, and lutein from spinach. Other well-known and well studied phytonutrients found in foods of colors include polyphenols and anthocyanins from berries and flavonoids found in apples and citrus (1, 2). Research has shown that people who eat a diet rich in colorful fruits and vegetables have a lower incidence of cancer; some attribute this to the protective agents in phytonutrients (3, 4). But despite this news, government studies show that Americans fall short of the minimal daily fruit and vegetable recommendations of 5 servings a day: 33% of adults say they eat enough fruit and 27% say they get enough vegetables (5). And these statistics shrink significantly when new recommendations of the National Cancer Institute are considered: some people are advised to get as many as 13 servings a day (6).  Whole fruit and vegetable supplements have become more popular in order to fill the diet gap that continues to widen.       

Clinical Studies for Foods of Color

Research studies show that a diet rich in colorful fruits and vegetables can prevent degenerative diseases; and now, more studies show that a significant benefit comes from phytonutrient chemicals (7, 8). Researchers have found that these pigment and flavor compounds protect and treat conditions like cancer, heart and eye disease, diabetes and hypertension (7, 8). More specific studies have isolated the benefits of individual phytonutrients like lutein found in spinach. A survey study of 350 macular degeneration patients found that those who regularly ate spinach or other green leafy vegetables were less likely to develop the age-related degenerative vision disease (9). And in another large-scale human study, tomato intake was linked to lower incidence of prostate cancer in more than 50,000 men in the United States. Tomatoes are rich in the phytonurient lycopene. The men in this study who benefited the most say they consumed tomato sauce as a regular part of their diet (10). Other researchers are finding similar results in human clinical trials with freeze-dried fruit and vegetable supplements. A control trial of 38 healthy volunteers tested the cardio-vascular effects of a comprehensive fruit and vegetable phytonutrient supplement. Subjects were fed a high fat meal and then tested for arterial blood flow, which was inhibited. The same test was given again after four weeks of phytonutrient treatment or placebo. Arterial blood flow in the treatment group was improved after the second test as compared to placebo; all volunteers were fed a high-fat, 900-calorie meal previous to each test (11). The results of an impending human study on freeze dried berries and berry extracts, rich in polyphenols and anthocyanins, show similar results to earlier tests done with animals: these compounds reduce the incidence of colon cancer and colon polyps significantly (12).             

Foods of Color References

1. Drewnowski A, Gomez-Carneros C. Bitter taste, phytonutrients, and the consumer: a review. Am J Clin Nutr. 2000; 72(6): 1424-1435.
2. Phytonutrient FAQs. United States Department of Agriculture: Agricultural Research Service. http://www.ars.usda.gov/Aboutus/docs.htm?docid=4142
3. Block G et al. Fruit, vegetables, and cancer prevention: a review of the epidemiological eveidence. Nutr Cancer. 1992; 18(1): 1-29.
4. Steinmetz KA, Potter JD. Vegetables, fruit, and cancer prevention: a review. J Am Diet Assoc. 1996; 96(10): 1027-1039.
5. Fruit and vegetable consumption among adults-United States, 2005. MMWR weekly: Centers for Disease Control (CDC). 2007; 56(10); 213-217.
6. CDC: For Health Professionals. About the National Fruit & Vegetable Program. 2007; http://www.fruitsandveggiesmatter.gov/health_professionals/about.html.
7. Craig WJ. Phytochemicals: guardians of our health. J Am Diet Assoc. 1997; 97(10 Suppl 2): S199-204.
8. Dragsted LO et al. Cancer-protective factors in fruits and vegetables: biochemical and biological background. Pharmacol Toxicol. 1993; 72 (Suppl 1): 116-135.
9. Seddon JM et al. Dietary carotenoids, vitamins A, C, and E and advanced age-related macular degeneration. Eye Disease Case-Control Study Group. JAMA. 1994; 272(18): 1413-1420.
10.   Giovannucci E et al. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst. 2002; 94(5): 391-398.
11. Plotnick GD et al. Effect of supplement phytonutrients on impairment of the flow-mediated brachialartery vasoactivity after a single high-fat meal. J Am Coll Cardiol. 2003; 41: 1744-1749.
12. Stoner GD et al. Cancer prevention with freeze-dried berries and berry components. Semin Cancer Biol. 2007; 17(5): 403-410.