Evaluation of dietary factors in relation to the biomarkers of oxidative stress and inflammation in breast cancer risk.

OBJECTIVE: This study was conducted to evaluate blood concentrations of inflammatory cytokines and oxidative stress-related biomarkers as risk factors of breast cancer and to determine the relation between these markers and antioxidant nutrient intake. METHODS: Study subjects were 134 patients with breast cancer and 149 controls. Total antioxidant capacity and concentrations of 8-isoprostane, 8-hydroxy-2'-deoxyguanosine, interleukin (IL)-1ß, IL-6, and IL-8 of blood samples were determined. A food-frequency questionnaire was used to assess nutrient intake. RESULTS: Patients with breast cancer had significantly higher blood levels of oxidative stress markers compared with control subjects. Plasma concentrations of IL-1ß and IL-6 were significantly higher in patients with breast cancer compared with those of control subjects. In the pooled analysis, total antioxidant capacity was significantly decreased with increasing quartiles of carbohydrate intake but was increased with increasing quartiles of total vitamin A intake and vitamin C intake. In addition, 8-hydroxy-2'-deoxyguanosine concentration was decreased with increasing quartiles of vitamin A and ß-carotene. No significant association was found between nutrient intake and cytokine concentrations. CONCLUSIONS: These results suggest that oxidative stress and inflammation may be associated with the risk of breast cancer. Total vitamin A intake was negatively related to oxidative stresses, possibly modifying the risk of breast cancer.

Dietary intake and serum levels of iron in relation to oxidative stress in breast cancer patients.

Iron may induce oxidative stress via production of reactive oxygen species, facilitating mammary carcinogenesis. This study investigated the role of iron in relation to oxidative stress as a potential risk factor in the development of breast cancer (BC). BC patients (n = 121) and healthy age-matched controls (n = 149) were entered into the study. Iron and antioxidant vitamins intakes were estimated using a quantitative food frequency questionnaire. Thirty one subjects from each group provided blood samples for measurement of serum iron, plasma malondialdehyde (MDA) and ferric reducing ability of plasma (FRAP). Total and non-heme iron intake of BC patients were lower than those of the controls. However, the serum iron level was significantly higher in BC patients. Plasma MDA levels were also significantly higher in BC patients whereas no significant difference in FRAP values were observed between the two groups. Log-transformed serum iron concentration showed no significant correlation with MDA or FRAP. These results suggest that serum iron overload may be a breast cancer risk factor possibly due to increased oxidative stress.

Comparisons of food intake between breast cancer patients and controls in Korean women.

The purpose of this study was to compare food intakes between Korean breast cancer patients and a healthy control group. We compared the intake of nutrients of 117 food items between Korean breast cancer patients (n=97) and age matched healthy controls (n=97). Nutrient intake was estimated using a quantitative food frequency questionnaire. The mean caloric intake of breast cancer patients and healthy controls was not significantly different. Breast cancer patients consumed significantly less fat and antioxidant nutrients such as vitamin A, retinol, beta-carotene, vitamin C and vitamin E when compared to the control subjects. Among the food items, the intake of eggs (p<0.01), legumes (p<0.05), vegetables (p<0.05), seasonings (p<0.001), and oils and fats (p<0.01) in breast cancer patients was significantly lower than that in the controls. These results suggest that Korean breast cancer patients consumed less amount of soy and vegetables, which are rich source of antioxidant nutrients and phytosterols. Thus, dietary guidance to increase intake of these foods may be beneficial in the prevention of breast cancer.