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Phytochemicals

Phytochemicals are chemicals in plants that may provide some health benefits. Carotenoids are one type of phytochemical. Phytochemicals also include indoles, lignans, phytoestrogens, stanols, saponins, terpenes, flavonoids, carotenoids, anthocyanidins, phenolic acids, and many more.[1] They are found not only in fruits and vegetables, but also in grains, seeds, nuts, and legumes.

Many phytochemicals act as antioxidants, but they have several other functions, such as mimicking hormones, altering absorption of cholesterol, inhibiting inflammatory responses, and blocking the actions of certain enzymes.

Phytochemicals are present in small amounts in the food supply, and although thousands have been and are currently being scientifically studied, their health benefits remain largely unknown. Also largely unknown is their potential for toxicity, which could be substantial if taken in large amounts in the form of supplements.[2] Moreover, phytochemicals often act in conjunction with each other and with micronutrients. Thus, supplementing with only a few may impair the functions of other phytochemicals or micronutrients. As with the antioxidant vitamins, it is the mixture and variety of phytochemicals in foods that are linked to health benefits.

Table 9.33 Some Phytochemical’s Obtained from Diet and Their Related Functions
Phytochemical Phytochemical Source Phytochemical Function:
Carotenoid Yellow-orange fruits, dark green leafy vegetables May possess strong cancer-fighting properties[3]
Indoles Cruciferous vegetables (i.e. bok choy, broccoli, choy sum) May inhibit the development of cancer-causing hormones and prevent tumor growth[4]
Phytoestrogen Grapes, berries, plums, soybeans, tofu, garlic May lower the risk for osteoporosis, heart disease, breast cancer, and menopausal symptoms[5]
Stanols Grains, nuts, legumes May lower blood cholesterol levels and reduce the risk of heart disease and stroke[6]
Saponins Broad beans, kidney beans, lentils May decrease blood lipids, lower cancer risks, and lower blood glucose responsefootnote]Shi, J., Arunasalam, K., Yeung, D., Kakuda, Y., Mittal, G., & Jiang, Y. (2004). Saponins from Edible Legumes: Chemistry, Processing, and Health Benefits. Journal of Medicinal Food, 7 (1): 67–78. https://doi.org/10.1089/109662004322984734.Accessed August 13, 2025. [/footnote]
Terpenes Citrus fruits May slow cancer cell growth, aid in immune system support, and prevent virus related illness[7]
Flavonoids Fruits, vegetables, chocolates, wines, teas, nuts, seeds May benefit the immune system and prevent cancer cell growth.[8][9]
Anthocyanins Fruits and vegetables with vibrant colors of orange, red, purple, and blue May prevent cardiovascular disease, reduce cancer cell proliferation (growth/multiplication) and inhibit tumor formation.[10][11]
Phenolic acids Coffee, fruits, vegetables, nuts, cereals, legumes, oilseeds, beverages and herbs May prevent cellular damage due to free-radical oxidation reaction and promote anti-inflammatory conditions in the body.[12]

 

Learning Activities

Technology Note: The second edition of the Human Nutrition Open Educational Resource (OER) textbook features interactive learning activities.  These activities are available in the web-based textbook and are not in downloadable versions (EPUB, Digital PDF, Print_PDF, or Open Document).

Learning activities may be used across various mobile devices; however, for the best user experience, it is strongly recommended that users complete these activities using a desktop or laptop computer.

  1. Phytochemicals. Villanova University Office of Health Promotion.https://www1.villanova.edu/content/dam/villanova/studentlife/documents/healthpromotion/Phytochemicals%20-%20Final.pdf. Accessed August 13, 2025. ↵
  2. Patisaul, H. B., & Jefferson, W. (2010). The Pros and Cons of Phytoestrogens. Frontiers in Neuroendocrinology, 31 (4): 400–419. https://doi.org/10.1016/j.yfrne.2010.03.003. Accessed August 13, 2025. ↵
  3. Xu, D-P., Li, Y., Meng, X., Zhou, T., Zhou, Y., Zheng, J., Zhang, J.-J., & Li, H.-B. (2017). Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources. International Journal of Molecular Sciences, 18 (1): 96. https://doi.org/10.3390/ijms18010096. Accessed August 13, 2025 ↵
  4. Higdon, J. V., Delage, B., Williams, D. E., & Dashwood, R. H. (2007). Cruciferous Vegetables and Human Cancer Risk: Epidemiologic Evidence and Mechanistic Basis. Pharmacological Research : The Official Journal of the Italian Pharmacological Society, 55 (3): 224–236. https://doi.org/10.1016/j.phrs.2007.01.009. Accessed August 13, 2025 ↵
  5. Bacciottini, L., Falchetti, A., Pampaloni, B., Bartolini, E., Carossino, A. M., & Brandi, M. L. (2007). Phytoestrogens: Food or drug? Clinical Cases in Mineral and Bone Metabolism, 4 (2): 123–130. ↵
  6. Thompson, G. R., & Grundy, S. M. (2005). History and Development of Plant Sterol and Stanol Esters for Cholesterol-Lowering Purposes. The American Journal of Cardiology, 96 (1, Supplement): 3–9. https://doi.org/10.1016/j.amjcard.2005.03.013. Accessed August 13, 2025. ↵
  7. Goto, T., Takahashi, N., Hirai, S., & Kawada, T. (2010). Various Terpenoids Derived from Herbal and Dietary Plants Function as PPAR Modulators and Regulate Carbohydrate and Lipid Metabolism. PPAR Research, 2010. https://doi.org/10.1155/2010/483958. Accessed August 13, 2025. ↵
  8. Kozłowska, A., & Szostak-Wegierek, D. (2014). Flavonoids—Food sources and health benefits. Roczniki Panstwowego Zakladu Higieny, 65 (2): 79–85. ↵
  9. Flavonoids. Linus Pauling Institute. https://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/flavonoids. Updated January 2016. Accessed August 13, 2025. ↵
  10. Yousuf, B., Gul, K., Wani, A. A., & Singh, P. (2016). Health Benefits of Anthocyanins and Their Encapsulation for Potential Use in Food Systems: A Review. Critical Reviews in Food Science and Nutrition, 56 (13): 2223–2230. https://doi.org/10.1080/10408398.2013.805316. Accessed August 13, 2025. ↵
  11. Bagchi, D., Sen, C. K., Bagchi, M., & Atalay, M. (2004). Anti-angiogenic, antioxidant, and anti-carcinogenic properties of a novel anthocyanin-rich berry extract formula. Biochemistry (Biokhimiia), 69 (1): 75–80, 1 p preceding 75. https://doi.org/10.1023/b:biry.0000016355.19999.93. Accessed August 13, 2025. ↵
  12. Zamora-Ros, R., et al. (2013). Dietary intakes and food sources of phenolic acids in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The British Journal of Nutrition, 110 (8): 1500–1511. https://doi.org/10.1017/S0007114513000688. Accessed August 13, 2025. ↵
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