Biomedical subjects

Zora Djuric

Publications and source records attributed to Zora Djuric.

8 recordsLinked to original sources

PubMed2003

Plasma carotenoids, tocopherols, and antioxidant capacity in a 12-week intervention study to reduce fat and/or energy intakes.

OBJECTIVE: We examined plasma levels of carotenoids, tocopherols, and total antioxidant activity in women before and after dietary intervention to reduce fat and/or energy intakes. Dietary fat and energy may affect intake and bioavailability of carotenoids and tocopherols, and these micronutrient levels in turn can contribute to the antioxidant capacity of plasma. METHODS: Women were randomized onto one of four diets for 12 wk: non-intervention, low fat (15% of energy from fat with maintenance of energy intake), low energy (25% energy reduction with maintenance of percentage of energy from fat), and combined low fat and low energy. Fasting plasma was available for analysis from a subset (n = 41) of women enrolled in the study. RESULTS: Levels of carotenoids and tocopherols did not change significantly over 12 wk on any diet arm, despite a modest but statistically significant increase in fruit and vegetable intake in the women following the low-fat diet (from 3.3 to 5.2 servings/d excluding potatoes). Levels of Trolox-equivalent antioxidant capacity (TEAC), total cholesterol, and two major plasma antioxidants (urate and bilirubin) also did not change significantly. Of the individual micronutrients measured, lycopene and lutein/zeaxanthin correlated most strongly with TEAC values, and the correlation with lycopene was statistically significant before intervention. CONCLUSION: The decreases in dietary fat and energy intakes in this study were quite large, but this did not appear to have detrimental effects on plasma micronutrient levels, nor did it appreciably affect plasma antioxidants. Because lycopene levels were significantly associated with plasma TEAC before intervention, interventions that increase levels of lycopene might be more likely to increase the antioxidant capacity of plasma.

Adult↗

PubMed2002

Combining weight-loss counseling with the weight watchers plan for obese breast cancer survivors.

OBJECTIVE: The objective was to develop effective weight-loss methods for women who have had breast cancer, because obesity may result in an adverse prognosis. RESEARCH METHODS AND PROCEDURES: This randomized pilot study tested an individualized approach toward weight loss in obese women who have had a diagnosis of breast cancer. An individualized approach was applied either alone or combined with the commercial Weight Watchers program. Forty-eight women (body mass index of 30 to 44 kg/m(2)) were enrolled. RESULTS: Weight change after 12 months of intervention was as follows (mean +/- SD): 0.85 +/- 6.0 kg in the control group, -2.6 +/- 5.9 kg in the Weight Watchers group, -8.0 +/- 5.5 kg in the individualized group, and -9.4 +/- 8.6 kg in the comprehensive group that used both individualized counseling and Weight Watchers. Weight loss relative to control was statistically significant in the comprehensive group 3, 6, and 12 months after randomization, whereas weight loss in the individualized group was significant only at 12 months. Weight loss of 10% or more of initial body weight was observed in 6 of 10 women in the comprehensive group at 12 months. In the comprehensive and Weight Watchers-only groups, weight loss was significantly related to frequency of attendance at Weight Watchers meetings, and attendance was more frequent in the comprehensive group. DISCUSSION: These data indicate that the most weight loss was achieved when the counseling approach combined both Weight Watchers and individualized contacts. This was effective even though most of the individualized contacts were by telephone.

Adolescent↗

PubMed2002

Effect of low-fat and/or low-energy diets on anthropometric measures in participants of the women's diet study.

OBJECTIVE: To compare the effects of low-fat, low-energy and combination low-fat/low-energy intervention on changes in six anthropometric measures in Caucasian and African-American free-living women. METHODS: The effects of dietary counseling strategies for fat and/or energy reduction were examined on anthropometric measures in 86 pre-menopausal women, average BMI of 28 kg/m2, who participated in a 12-week intervention trial called the Women's Diet Study. The dietary goals were 15% of energy from fat and/or 25% reduction in energy intake, relative to reported baseline intake, using a 2 x 2 factorial design. Analysis of covariance models were constructed to evaluate changes in anthropometric measures over the 12 weeks of study. RESULTS: The biggest difference by race was in women who were relatively heavier at baseline, in which case African-American women lost significantly less weight but decreased their waist:hip ratio to a significantly greater extent than Caucasian women. With regard to the effects of diet arm, weight loss varied depending on baseline weight, and in women with higher baseline weights, the combination low-fat/low-energy diet resulted in the most weight loss (6.7 kg, p < 0.05). Decreases in the other anthropometric measures at week 12 were more uniform across diet arms and did not depend on baseline values. After controlling for previous weight history and race, the decreases in BMI, percent body fat and waist circumference after 12 weeks were statistically equivalent with the low-fat, low-energy or combination low-fat/low-energy diets. The relatively greater decreases in percent body fat and waist circumference with the combination diet versus the low-fat or low-energy diets were not statistically significant. CONCLUSION: The low-fat, low-energy and combination diets all resulted in similar and statistically significant decreases in BMI, percent body fat and waist circumference over 12 weeks of intervention. The extent of weight loss, however, varied depending on baseline weight, and the combination diet was the only intervention to result in significant weight loss for women who were heavier at baseline. This indicates that, although there may be an advantage for reducing dietary fat in initially heavier women, any of these counseling strategies could be effective for improving anthropometric predictors of health risks associated with overweight status. This is useful since flexibility in dietary choices may facilitate adherence to dietary counseling in some individuals.

Adult↗

PubMed2002

Effect of varying caloric restriction levels on female rat growth and 5-hydroxymethyl-2'-deoxyuridine in DNA.

Caloric restriction has previously been shown to decrease levels of oxidative stress in rats. In this study, we examined the effects of 5 different caloric intake levels on one type of oxidative DNA damage in rat mammary gland, blood, and liver. Animals were fed modified AIN-93G diets to accommodate 10, 20, 30, or 40% calorie restriction (CR), relative to ad libitum (AL) consumption. The intakes of fat, protein, vitamins, and minerals thus remained constant, but total carbohydrate intake decreased. Body weights of the animals at 20 weeks reflected the degree of restriction, but in the first 10 weeks, weight gain in the 10% CR group was not reduced relative to animals fed ad libitum. Levels of 5-hydroxymethyl-2'-deoxyuridine increased with time in mammary gland and nucleated blood cells regardless of CR level, indicating an effect of animal age, despite the fact that the animals were only 7 months old after the 20-week dietary study. In liver, however, there was a trend towards decreased DNA damage levels with time. The effect of diet on levels of 5-hydroxymethyl-2'-deoxyuridine was not statistically significant, indicating no protective effect of restricted dietary carbohydrate. This dietary study differed from previous work in that the modified AIN-93G dietary formulation contains relatively higher levels of fat and vitamins K, E, and B(12), and it has certain added trace minerals. This data raises the question of whether the previously reported effects of calorie restriction on preventing oxidative stress in mammary gland are dependent on the type of dietary formulation used.

Animals↗

PubMed2002

Effects of lycopene supplementation in patients with localized prostate cancer.

Epidemiological studies have shown an inverse association between dietary intake of lycopene and prostate cancer risk. We conducted a clinical trial to investigate the biological and clinical effects of lycopene supplementation in patients with localized prostate cancer. Twenty-six men with newly diagnosed prostate cancer were randomly assigned to receive a tomato oleoresin extract containing 30 mg of lycopene (n = 15) or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of cell proliferation and apoptosis were assessed by Western blot analysis in benign and cancerous prostate tissues. Oxidative stress was assessed by measuring the peripheral blood lymphocyte DNA oxidation product 5-hydroxymethyl-deoxyuridine (5-OH-mdU). Usual dietary intake of nutrients was assessed by a food frequency questionnaire at baseline. Prostatectomy specimens were evaluated for pathologic stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1, insulin-like growth factor binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. After intervention, subjects in the intervention group had smaller tumors (80% vs 45%, less than 4 ml), less involvement of surgical margins and/or extra-prostatic tissues with cancer (73% vs 18%, organ-confined disease), and less diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia (33% vs 0%, focal involvement) compared with subjects in the control group. Mean plasma prostate-specific antigen levels were lower in the intervention group compared with the control group. This pilot study suggests that lycopene may have beneficial effects in prostate cancer. Larger clinical trials are warranted to investigate the potential preventive and/or therapeutic role of lycopene in prostate cancer.

Adenocarcinoma↗

PubMed2002

Methods to increase fruit and vegetable intake with and without a decrease in fat intake: compliance and effects on body weight in the nutrition and breast health study.

Dietary patterns that involve a decrease in fat and an increase in fruit and vegetable (FV) intake have been suggested to decrease cancer risks. In this study, intervention methods to selectively modify dietary fat and/or FV intakes were developed. Compliance to the diets and the effects on body weight are shown, because both of these dietary changes can impact on and be confounded by changes in energy intake. A total of 122 women with a family history of breast cancer were randomized onto one of four diets for 12 mo. Counseling methods were devised to increase amount and variety of FV consumed with or without a decrease in fat intake using modified exchange list diets. Women on the low-fat and combination low-fat/high-FV diet arms decreased their fat intakes to approximately 16% of energy. Women on the high-FV and the combination low-fat/high-FV diet arms increased FV intakes to approximately 11 servings/day. Despite counseling efforts to maintain baseline energy intakes, mean body weight increased significantly by 6 pounds in women in the high-FV diet arm and decreased significantly by 5 pounds in women in the low-fat diet arm. Percent body fat also was increased in the high-FV diet arm and decreased in the low-fat diet arm. Body weight and percent body fat in the combination diet arm did not change significantly. Control of energy intake, therefore, appears to have been achieved only when the addition of FV to the diet was balanced by a decrease in fat intake and both dietary components were enumerated daily. Maintenance of energy intake, therefore, did not appear to be attained intrinsically when individuals were counseled to make changes in the composition of their diets.

Adipose Tissue↗

PubMed2002

Detection of 2,6-cyclolycopene-1,5-diol in breast nipple aspirate fluids and plasma: a potential marker of oxidative stress.

An high-performance liquid chromatography method with electrochemical detection was developed to quantify both 2,6-cyclolycopene-1,5-diol and lycopene in plasma and breast nipple aspirate fluids (NAF). As an example of the utility of this assay, levels in plasma and NAF of 11 women were examined and compared with levels of 8-isoprostane, a commonly used marker of lipid oxidation. Levels of 2,6-cyclolycopene-1,5-diol and 8-isoprostane were higher in NAF than in plasma, but levels of lycopene were lower in NAF than in plasma. Levels of 2,6-cyclolycopene-1,5-diol in plasma and in NAF were significantly correlated with both lycopene and 8-isoprostane levels. This is consistent with the dependence of 2,6-cyclolycopene-1,5-diol levels on both dietary intakes of lycopene and oxidative stress levels. For the correlations between NAF and plasma, lycopene levels were significantly correlated, whereas 2,6-cyclolycopene-1,5-diol levels were not, indicating that levels of 2,6-cyclolycopene-1,5-diol in NAF are difficult to predict from plasma levels. The high levels of 2,6-cyclolycopene-1,5-diol and 8-isoprostane in NAF are consistent with high levels of oxidative stress in the breast.

Adult↗

PubMed2000

An Evaluation of Plasma Antioxidant Levels and the Risk of Breast Cancer: A Pilot Case Control Study.

Antioxidant micronutrients found in fruits and vegetables have been shown in numerous studies to be protective against cancer. There is limited information on the relationship between blood antioxidant micronutrient levels and cancer among ethnic minorities. We conducted a pilot case-control study to evaluate the potential for accrual to a study of the association of plasma levels of beta-carotene, retinol, lycopene, alpha-tocopherol, and gamma-tocopherol with breast cancer risk among African American and Caucasian women seen at a large university medical center in Detroit. Cases included women with newly diagnosed invasive breast cancer who had not yet had any cancer-related therapy and who were age-matched to controls within 5 years. Plasma levels of micronutrients were analyzed by high-pressure liquid chromatography. Compared to the expected accrual based on cancer registry data, only 26% (11/42) of African American women with breast cancer enrolled, while 100% (16/16) of Caucasian cases enrolled. Control women were quickly accrued with only a 6% refusal rate. Among African American women, there was a weak inverse association between plasma lycopene levels and breast cancer risk, with a mean level of 0.17 &mgr;mol/L (SD = 0.18) among cases, and 0.24 &mgr;mol/L (SD = 0.18) among controls (p = 0.09). There was a weak direct association between plasma retinol levels and breast cancer risk among African American women, with a mean retinol level of 2.37 &mgr;mol/L (SD = 0.73) among cases and 1.98 &mgr;mol/L (SD = 0.49) among controls (p = 0.132). The interaction effect of race and lycopene was statistically significant (p = 0.048). Among the lowest lycopene tertile, the risk of breast cancer among Caucasian women was 0.76 and the risk of breast cancer among African American women was 2.29, although these odds ratios were not statistically significant. Our recruitment efforts were largely successful among Caucasian cases and controls, and African American controls, but were unsuccessful among African American cases. The results suggest a possible relationship between plasma lycopene level and breast cancer among African American women, but these results should be confirmed by a larger, more definitive study.

Journal Article↗