Phytonutrients

Phytonutrients Clinical Report Summary

Human research shows that phytonutrients from food and supplements can prevent the development of cancer, heart disease and macular degeneration (1, 2, 3, 4, 7, 8, 9, 10, 11). Phytonutrients are rich in antioxidants and generally found in colorful fruits and green leafy vegetables (1, 2). In order to get the benefit from these nutrients, experts recommend 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. 

Phytonutrients Overview

Phytonutrients are organic compounds found in fruits, vegetables and other foods that provide deep color and intense taste (1, 2). Hundreds of these wide-ranging compounds exist and provide a natural defense system for the plants they inhabit. Phytonutrients, sometimes called phytochemicals, help protect fruits and vegetables from disease and cell damage; research finds evidence that they do the same for people (1, 2). Phytonutrients are not traditional nutrients like vitamins or minerals but are usually high in anti-oxidant properties (1, 2). The most common classes of phytonutrients include carotenoids found in carrots and spinach, polyphenols from berries, flavonoids found in apples and citrus, and isoflavones from soy (1, 2). Research has shown that people who eat a diet rich in certain 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.       

Safe Use of Phytonutrients

Dosages are hard to determine at this time because there are hundreds, if not thousands, of phytonutrients with many different benefits to human health. Phytonutrients, like fruits and vegetables, are generally well tolerated with few side effects. People with fruit allergies may also react to phytonutrient supplements.     

Clinical Reports for Phytonutrients

Research studies show that a diet rich in fruits and vegetables can prevent degenerative diseases; and now, more studies show that 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 most regularly consumed tomato sauce in 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 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, show similar results to tests in animals: these compounds reduce the incidence of colon cancer and colon polyps significantly (12).             

Phytonutrient 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.