Apples, broccoli, cranberries

Nutrition & Health Info Sheets for Consumers - Flavonols

Nutrition & Health Info Sheets contain up-to-date information about nutrition, health, and food. They are provided in two different formats for consumer and professional users. These resources are produced by Dr. Rachel Scherr and her research staff. Produced by Karrie Heneman, PhD, Sheri Zidenberg-Cherr, PhD, UC Cooperative Extension Center for Health and Nutrition Research, Department of Nutrition, University of California, Davis, 2008.

What are flavonols?

Flavonols are phytochemical compounds found in a variety of plant based foods including apples, apricots, beans, broad beans, broccoli, cherry tomatoes, chives, cranberries, kale, leeks, pear, onions, red grapes, sweet cherries, and white currants (1).

Are there beneficial effects associated with consumption of flavonols?

Consumption of flavonols, such as quercitin, kaempferol, and myricetin, has been associated with a variety of beneficial effects including a reduced risk of cancer and cardiovascular disease (2).

There is a lot of media hype around apples, broccoli, and cranberries. Are these really “super foods”?

  • Apples
    • Research has found that consumption of apples reduced risk of oral, pharynx, esophagus, colon, larynx, breast, ovary and prostate cancer (3); cardiovascular disease, cardiovascular events, coronary mortality, and thrombotic stroke (4); asthma, bronchial sensitivity, and chronic obstructive pulmonary disease (4); and type 2 diabetes (5).
    • In light of these findings, consuming an apple a day as part of your daily recommended intake of a variety of fruits and vegetables may be beneficial to overall health.
  • Broccoli
    • Current research suggests that consumption of broccoli is associated with a reduced risk of breast (6), prostate (7), bladder (8), lung, colon, thyroid, and stomach cancer in addition to cancer of the respiratory tract and reproductive organs (9).
    • Conclusions: In light of this research, the American Cancer Society recommends consuming broccoli as part of a balanced diet that includes foods from a variety of plant sources.
  • Cranberries
    • Current scientific evidence suggests that consumption of cranberry products can prevent new urinary tract infections (10) and reduce risk of cardiovascular disease (11).
    • Conclusions: The Dietary Guidelines for Americans, 2005 recommends limiting consumption of juice to ensure adequate intake of fiber (31g/ 2000 kcals). For women prone to urinary tract infections, consuming ½ cup of cranberry juice daily may help to reduce the number of new infections.

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  1. Aherne SA, and O'Brien NM. Dietary flavonols: chemistry, food content, and metabolism. Nutrition; 2002; 18: 75-81.
  2. Williamson G, and Manach C. Bioavailability and bioefficacy of polyphenols in humans. II. Review of 93 intervention studies. Am J Clin Nutr; 2005; 81: 243S-255S.
  3. Gallus S, et al. Does an apple a day keep the oncologist away? Ann Oncol; 2005; 16: 1841-4.
  4. Boyer J, and Liu RH. Apple phytochemicals and their health benefits. Nutr J; 2004; 3: 5.
  5. Song Y, et al. Associations of dietary flavonoids with risk of type 2 diabetes, and markers of insulin resistance and systemic inflammation in women: a prospective study and cross-sectional analysis. J Am Coll Nutr; 2005; 24: 376-84.
  6. Ambrosone CB, et al. Breast cancer risk in premenopausal women is inversely associated with consumption of broccoli, a source of isothiocyanates, but is not modified by GST genotype. J Nutr; 2004; 134: 1134-8.
  7. Kirsh VA, et al. Prospective study of fruit and vegetable intake and risk of prostate cancer. J Natl Cancer Inst; 2007; 99: 1200-9.
  8. Michaud DS, et al. Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort. J Natl Cancer Inst; 1999; 91: 605-13.
  9. Verhoeven DT, et al. Epidemiological studies on brassica vegetables and cancer risk. Cancer Epidemiol Biomarkers Prev; 1996; 5: 733-48.
  10. Jepson RG, and Craig JC. A systematic review of the evidence for cranberries and blueberries in UTI prevention. Mol Nutr Food Res; 2007; 51: 738-45.
  11. Ruel G, et al. Changes in plasma antioxidant capacity and oxidized low-density lipoprotein levels in men after short-term cranberry juice consumption. Metabolism; 2005; 54: 856-61.

Production of this material was supported by a grant from the Vitamin Cases Consumer Settlement Fund, created as a result of an antitrust class action. One of the purposes of the fund is to improve the health and nutrition of California consumers.

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Copyright © The Regents of the University of California, Davis campus, 2018. All rights reserved. Inquiries regarding this publication may be directed to The information provided in this publication is intended for general consumer understanding, and is not intended to be used for medical diagnosis or treatment, or to substitute for professional medical advice.