Antioxidant biomarkers and food intake in elderly women.

OBJECTIVE: To investigate the relationship between antioxidant biomarkers and food intake in elderly women. DESIGN: Cross-sectional study. SETTING: Recreation Center for the Elderly in the city of Itajaí, Santa Catarina, Brazil. PARTICIPANTS: 73 elderly women with an average age of 71 years, 93% caucasian, average body weight 68.7 ± 13.1 kg and average BMI 28.5 ± 2.3 kg/m². MEASUREMENTS: Nutritional status was assessed based on the Body Mass Index (BMI). Data on food intake were obtained by applying the 24h diet recall method in three non-consecutive days, including Sunday. The assessment of antioxidant biomarkers was performed based on tests for total plasma thiols and phenolic compounds. The linear regression analysis was used to assess the effect of the consumption of food groups on antioxidant biomarkers. RESULTS: A positive association was found between thiols and intake of carotenoid-rich vegetables (p=0.03), oils, fats and oilseeds (p=0.03); a negative association was observed between total concentrations of phenolic compounds and intake of cereals (p=0.04). CONCLUSION: The intake of foods from the carotenoid-rich vegetables, oils, fats and oilseeds food groups increased the levels of plasma thiols, and the intake of foods from the group of cereals decreased the plasma concentration of phenols. Studies should be conducted to investigate the association between the intake of antioxidant-rich foods and the plasma antioxidant profile, as a way to protect against the aging process.

Factors associated with oxidative stress in women with breast cancer.

OBJECTIVE: To assess the association between physiological, physical, lifestyle and nutritional variables and oxidative stress biomarkers in women with breast cancer. METHODS: This cross-sectional study was conducted on 55 women newly diagnosed with breast cancer. The extent of oxidative stress was analyzed by the measurement of plasma lipid hydroperoxides (LH), thiobarbituric acid reactive substances (TBARS), protein carbonyl, whole blood reduced glutathione (GSH) and serum antioxidant capacity (AC). Diet data were obtained from food frequency questionnaire. Linear regression was used to determine the association between the variables studied and oxidative stress biomarkers. The protein carbonyl data was not included in the linear regression analyses since the data did not show a normal distribution, even after logarithmic and other transformations. RESULTS: After adjusting for energy intake, the intake of chicken and high-fat dairy products was associated with increased levels of LH, while vitamin E intake was associated with decreased LH levels (R² = 23.8%). Intake of oils was associated with increased levels of TBARS (R² = 6.82%). Positive axillary lymph node status was associated with decreased levels of GSH (R² = 9.31%). Increasing age was directly associated with levels of AC, while animal fat, dairy product, and sweet food intakes were associated with low levels of AC (R² = 41.42%). CONCLUSION: Intake of chicken, vitamin E, dairy products (particularly high-fat dairy products), oils, animal fat, and sweet foods, along with axillary lymph node status and age, may be important determinants of oxidative stress in women with breast cancer.

Dietary intake and oxidative stress in breast cancer: before and after treatments.

OBJECTIVE: The aim of this study was to investigate changes in dietary intake, anthropometric parameters and markers of oxidative stress in 40 women who underwent surgery, chemotherapy or radiation therapy for breast cancer. METHODS: Pretreatment and post-treatment measurements included data collected through a food frequency questionnaire, weight and height to calculate the body mass index (BMI) and oxidative stress markers assessed from blood reduced glutathione (GSH), serum antioxidant capacity (AC), plasma thiobarbituric acid reactive substances (TBARS), serum lipid hydroperoxides (LH) and plasma carbonyls. Differences were compared using paired Student's t-test or paired Wilcoxon's test. RESULTS: A significant increase (P < 0.05) in the intake of the food groups: meat and eggs, dairy products, beans, oils and fats, as well as food from the subgroups: red meat, milk and other dairy products rich in fat, fruit rich in vitamin C and vegetable fats was found after treatments. There was a significant increase in body weight (P < 0.05), BMI (P < 0.05), levels of TBARS (P < 0.0001), LH (P < 0.005) and carbonyls (P < 0.0001) and a significant decrease of levels of AC (P < 0.005) and GSH (P < 0.0001). CONCLUSION: Breast cancer diagnosis and treatments were associated with dietary intake changes and increased body weight, BMI and oxidative stress. These potential changes have important implications for preventive nutrition counseling.