High dietary phytochemical intakes lower cancer risk in Korean elderly.

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Phytochemicals are known to prevent chronic diseases including cancer. Traditional Korean diets are rich in phytochemicals due to high intakes of fruits and vegetables. Despite this, cancer mortality has increased by 20% in the last 10 years, which might be associated with changing dietary patterns. This study was conducted to investigate the relationship between the dietary phytochemical intakes (flavonoids, carotenoids, and isoflavones), and cancer risk in Korean elderly. The mean ages of cancer and control subjects were 61.5±0.45 and 62.7±0.58 years, respectively. The cancer subjects were 291 hospitalized patients (48 liver, 88 colon, 116 stomach, and 38 others) and the control subjects were 168 hospitalized patients in the orthopedics ward of the same hospital and had no cancer history. The cancer and control subjects were matched by age and sex. Dietary intake assessments of the elderly subjects were carried out with personal interviews by a trained dietitian using a semi-quantitative food frequency questionnaire (CEFF-Qtns 2002-02-15-1971). Food items consist of 98 commonly consumed foods by Korean elderly based on the survey of 1998 Korean Nutrition & Health Survey with actual sized pictures. The phytochemical database was made from Korean published data and the USDA references and includes carotenoids (α-carotene, β-carotene, lycopene, lutein, zeaxanthin), flavonoids (quercetin, kaemferol, myricetin, ficetin, luteolin), and isoflavones (genistein, daidzein, glycitein, biochanin A, coumestrol). The total flavonoid and carotenoid intakes of cancer subjects (16.53±1.02 and 5.47±0.31 mg/1000kcal/day, respectively) were lower than those of the control subjects (20.92±1.93 and 8.67±0.21 mg/100kcal/day, respectively) when adjusted for energy intake. Odds ratio (OR) was adjusted for sex, age, education, monthly allowance, smoking, drinking, BMI, fat mass, total energy intake, and exercise. The adjusted OR of liver and stomach cancer for the highest versus the lowest flavonoid intake quintiles were 0.52 (95% CI=0.43–0.63) and 0.49 (95% CI=0.25–0.63), respectively. Corresponding adjusted OR of colon cancer for carotenoid intakes was 0.63 (95% CI=0.43–0.85). Isoflavone intakes were not associated with the cancer risk. Our finding thus suggests that high flavonoid and carotenoid intakes are associated with decreased cancer risk of Korean elderly.