The May 1, 2008 issue of the American Journal of Clinical Nutrition published the finding of investigators from the National Cancer Institute and other research centers of an association between a greater intake of dietary flavonoids and a lower risk of non-Hodgkin lymphoma (NHL), the fifth most common cancer in the United States. Flavonoids are polyphenolic plant compounds that have antioxidant and metal chelating properties. Some of these compounds have also been shown to have antiestrogenic and anticancer effects.
Four hundred sixty-six men and women with non-Hodgkin lymphoma were matched for age, gender, and other factors with 390 Medicare and Medicaid patients who did not have the disease. Dietary questionnaires completed by the participants were analyzed for intake levels of flavonoids (flavonols, flavanones, flavan-3-ols, and anthocyanidins), proanthocyanidins (monomers, dimmers, trimers, 4-6mers, 7-10mers and polymers), and isoflavones. Other than fruits and vegetables, sources of flavonoid intake in this study included wine, tea, nuts and chocolate.
Average calorie intake was significantly higher among those with NHL compared to the control group. High total flavonoid intake was significantly associated with a reduced risk of non-Hodgkin lymphoma, although not among current smokers. For those whose intake of flavonoids was in the top 25 percent of participants, there was a 47 percent lower risk of non-Hodgkin lymphoma compared with subjects whose intake was in the lowest fourth. Of flavonoid subclasses, flavonols, anthocyanidins, epicatechins, and proanthocyanidins were linked with a lower NHL risk. When subtypes of NHL were analyzed, the association of a high total intake of flavonoids with a reduced risk of disease remained similar to that of overall non-Hodgkin's risk.
Flavonoids' anticancer property has been proposed to exist via prevention of the formation of cancer-causing metabolites, inhibition of tumor cell proliferation, and stimulation of programmed tumor cell self-destruction (apoptosis). The researchers suggest that differing flavonoid metabolism or neutralization of reactive oxygen species in smokers may account for the variation in the protective association of flavonoids found between this group and nonsmokers in this study.
The results of the present study "support the associations seen in other studies of lower NHL risk in relation to plant food intake, and they suggest that specific flavonoid compounds within plants may be partly responsible," the authors conclude.Related Health Concern: Lymphoma
Lymphomas are linked to a variety of risk factors, including diet, medical history, environmental exposure to chemicals, and infections. To date, conventional medical treatment for lymphoma has been based on combinations of chemotherapy, radiotherapy, and stem cell therapy. However, new treatments for lymphoma now add to these traditional therapies the use of substances that can specifically target the delivery of radiotherapy to lymphoma cells (radioimmunotherapy) or activate the immune system to kill lymphoma cells (chemoimmunotherapy).
NHL is more common in individuals with weakened immune systems (Zhang S et al 1999; Zhang SM et al 2000). Clinical studies have now shown that diets rich in animal protein and fats, which are thought to diminish immune function (Calder PC et al 2002; Jones DE 2005; Plat J et al 2005), are associated with an increased risk of developing NHL (Chang ET et al 2005; Chiu BC et al 1996; De SE et al 1998; Zhang S et al 1999). Clinical studies have also shown that diets rich in fruits and vegetables, which are thought to enhance immune cell function (Gaisbauer M et al 1990; Rossing N 1988; Loghem JJ 1951), are associated with a reduced risk of developing NHL (Zhang SM et al 2000; Zheng T et al 2004).
The Life Extension Foundation suggests:
- Curcumin--up to 3.2 grams (g) daily (Gescher A 2004)
- Soy extract (containing up to 60 milligrams (mg) of isoflavones): twice daily (Anderson GD et al 2003)
- Vitamin A--40,000 to 50,000 international units (IU) daily (Kakizoe T 2003; Meyskens FL, Jr. et al 1995)
- Vitamin D3--16,000 IU three times weekly (Mellibovsky L et al 1993)
- Green tea--725 mg three times daily, or 10 cups of Japanese green tea (Laurie SA et al 2005; Pisters KM et al 2001)
- Vitamin C--2000 mg daily (Kakizoe T 2003)
- Vitamin E--400 IU daily (Kakizoe T 2003)
- Resveratrol--20 to 40 mg daily (Walle T et al 2004)
- Ginger--up to 6 g daily (Betz O et al 2005)
- Fish oil--4.8 g of EPA/DHA daily (Buckley R et al 2004)
- Garlic--600 mg of aged garlic extract twice daily.
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