Brassica vegetable consumption reduces urinary F2-isoprostane levels independent of micronutrient intake

Hydrogen sulfide and sulfaceutic or sulfanutraceutic agents: Classification, differences and relevance in preclinical and clinical studies

Hydrogen sulfide (H2S) has been extensively studied as a signal molecule in the body for the past 30 years. Researchers have conducted studies using both natural and synthetic sources of H2S, known as H2S donors, which have different characteristics in terms of how they release H2S. These donors can be inorganic salts or have various organic structures. In recent years, certain types of sulfur compounds found naturally in foods have been characterized as H2S donors and explored for their potential health benefits. These compounds are referred to as "sulfanutraceuticals," a term that combines "nutrition" and "pharmaceutical". It is used to describe products derived from food sources that offer additional health advantages. By introducing the terms "sulfaceuticals" and "sulfanutraceuticals," we categorize sulfur-containing substances based on their origin and their use in both preclinical and clinical research, as well as in dietary supplements.

Effect of DASH diet on oxidative stress parameters: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND AND AIMS

Oxidative stress (OS) is one of the main risk factors for several chronic diseases. The Dietary Approaches to Stop Hypertension (DASH) contain many antioxidants and may contribute to managing OS.

OBJECTIVE

To perform a systematic review and meta-analysis to examine the impacts of the DASH diet on OS parameters.

METHODS

A comprehensive electronic search in MEDLINE, Scopus, EMBASE, and the Cochrane Central Register of Controlled Trials was performed through September 2020 to find related studies evaluating the impact of the DASH diet on OS parameters. Standardized mean differences were pooled using random-effects meta-analysis.

RESULTS

Eight studies with a total of 317 subjects met our inclusion criteria. Four studies included in meta-analysis model with 200 participants (100 in treatment and 100 in control group). The DASH diet was associated with a statistically significant decrease in malondialdehyde (MDA) (SMD: -0.53; 95% CI: -0.89, -0.16; I² = 42.1%), and a significant increase in glutathione (GSH) (SMD: 0.83; 95% CI: 0.36, 1.03; I² = 42.1%). Meta-analysis found no statistically significant effect of DASH diet on nitric oxide (NO) (SMD: -1.40; 95% CI: -0.12, 1.93; I² = 92.6%) or total antioxidant capacity (TAC) levels (SMD: 0.95; 95% CI: -0.10, 1.99; I² = 87.6%).

CONCLUSION

Our results demonstrated that a DASH diet could significantly increase GSH and decrease MDA levels. Furthermore, there is a trend to improve TAC, NO, and f2-isoprostanes by the adherence to the DASH diet. However, long-term, large sample size and well-designed randomized clinical trials are still needed to draw concrete conclusions about DASH diet's effects on OS parameters.

A Review of Dietary (Phyto)Nutrients for Glutathione Support

Glutathione is a tripeptide that plays a pivotal role in critical physiological processes resulting in effects relevant to diverse disease pathophysiology such as maintenance of redox balance, reduction of oxidative stress, enhancement of metabolic detoxification, and regulation of immune system function. The diverse roles of glutathione in physiology are relevant to a considerable body of evidence suggesting that glutathione status may be an important biomarker and treatment target in various chronic, age-related diseases. Yet, proper personalized balance in the individual is key as well as a better understanding of antioxidants and redox balance. Optimizing glutathione levels has been proposed as a strategy for health promotion and disease prevention, although clear, causal relationships between glutathione status and disease risk or treatment remain to be clarified. Nonetheless, human clinical research suggests that nutritional interventions, including amino acids, vitamins, minerals, phytochemicals, and foods can have important effects on circulating glutathione which may translate to clinical benefit. Importantly, genetic variation is a modifier of glutathione status and influences response to nutritional factors that impact glutathione levels. This narrative review explores clinical evidence for nutritional strategies that could be used to improve glutathione status.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

Plasma F2-isoprostanes Are Positively Associated with Glycemic Load, but Inversely Associated with Dietary Polyunsaturated Fatty Acids and Insoluble Fiber in Postmenopausal Women

Background: Dietary factors, such as antioxidant nutrients, contribute significantly to the maintenance of an appropriate balance between antioxidant defense and free radical production in the body.Objective: The objective of this study was to examine the relation between oxidative stress as assessed by plasma F₂-isoprostane (IsoP) concentration, glycemic load (GL), glycemic index (GI), intake of antioxidant nutrients, dietary fiber, and polyunsaturated fatty acids (PUFAs).Methods: This study was a cross-sectional secondary analysis of baseline data collected from a random sample of 269 postmenopausal women participating in the Minnesota Green Tea Trial. GL, GI, and dietary variables were calculated from the diet history questionnaire. Subjects filled out surveys about the use of anti-inflammatory drugs and physical activity. Plasma IsoP concentration was assessed by GC-mass spectrometry. IsoP concentrations were compared across quartiles of GL, GI, insoluble fiber, PUFAs, and antioxidant nutrients with the use of linear regression.Results: Antioxidant supplement intake, including zinc, copper, vitamin C and vitamin E, was reported by >60% of the participants. Mean intake of PUFAs was 12.5 g. Mean plasma IsoP concentrations increased from 34 to 36.7 pg/mL in the lowest quartiles of GL and GI, respectively, to 45.2 and 41.6 pg/mL, respectively, in the highest quartiles (P-trend = 0.0014 for GL and P-trend = 0.0379 for GI), whereas mean IsoP concentrations decreased from 41.8 pg/mL in the lowest quartile of PUFAs to 34.9 pg/mL in the highest quartile (P-trend = 0.0416). Similarly, mean IsoP concentrations decreased from 44.4 pg/mL in the lowest quartile of insoluble fiber to 36 pg/mL in the highest quartile (P-trend = 0.0243) after adjustment for potential confounders.Conclusions: We concluded that dietary PUFAs and insoluble fiber are inversely associated with oxidative stress whereas GL and GI are positively associated with oxidative stress in postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00917735.

Effect of Cruciferous Vegetable Intake on Oxidative Stress Biomarkers: Differences by Breast Cancer Status

This post hoc analysis examined cruciferous vegetable intake on urinary oxidative metabolites in postmenopausal women. Intervention participants (n = 69) received cruciferous vegetables (≥14 cups/week) during a 3-week period. First morning urine measured 8-isoprostane and 8-hydroxy-2'-deoxyguanosine. Dietary intake was estimated using 24-h recalls. When stratified by history of breast cancer, those with breast cancer had significantly lower post-intervention urinary 8-hydroxy-2'-deoxyguanosine values in the intervention arm versus. the control arm (1.1 ng/mL vs. 3.2 ng/mL, p = .01) after adjustment for baseline 8-hydroxy-2'-deoxyguanosine. This was not observed in those without breast cancer. Further work is needed to understand the role of breast cancer in these relationships.

Circulating plant miRNAs can regulate human gene expression in vitro

While Brassica oleracea vegetables have been linked to cancer prevention, the exact mechanism remains unknown. Regulation of gene expression by cross-species microRNAs has been previously reported; however, its link to cancer suppression remains unexplored. In this study we address both issues. We confirm plant microRNAs in human blood in a large nutrigenomics study cohort and in a randomized dose-controlled trial, finding a significant positive correlation between the daily amount of broccoli consumed and the amount of microRNA in the blood. We also demonstrate that Brassica microRNAs regulate expression of human genes and proteins in vitro, and that microRNAs cooperate with other Brassica-specific compounds in a possible cancer-preventive mechanism. Combined, we provide strong evidence and a possible multimodal mechanism for broccoli in cancer prevention.

Chemopreventive properties of 3,3'-diindolylmethane in breast cancer: evidence from experimental and human studies

Diet is a modifiable factor associated with the risk of several cancers, with convincing evidence showing a link between diet and breast cancer. The role of bioactive compounds of food origin, including those found in cruciferous vegetables, is an active area of research in cancer chemoprevention. This review focuses on 3,3'-diindolylmethane (DIM), the major bioactive indole in crucifers. Research of the cancer-preventive activity of DIM has yielded basic mechanistic, animal, and human trial data. Further, this body of evidence is largely supported by observational studies. Bioactive DIM has demonstrated chemopreventive activity in all stages of breast cancer carcinogenesis. This review describes current evidence related to the metabolism and mechanisms of DIM involved in the prevention of breast cancer. Importantly, this review also focuses on current evidence from human observational and intervention trials that have contributed to a greater understanding of exposure estimates that will inform recommendations for DIM intake.

Epigenetic Regulation by Sulforaphane: Opportunities for Breast and Prostate Cancer Chemoprevention

Sulforaphane (SFN) is a phytochemical derived from cruciferous vegetables that has multiple molecular targets and anti-cancer properties. Researchers have demonstrated several chemopreventive benefits of SFN consumption, such as reductions in tumor growth, increases in cancer cell apoptosis, and disruption of signaling within tumor microenvironments both in vitro and in vivo. Emerging evidence indicates that SFN exerts several of its chemopreventive effects by altering epigenetic mechanisms. This review summarizes evidence of the impact of SFN on epigenetic events and how they relate to the chemopreventive effects of SFN observed in preclinical and clinical studies of breast and prostate cancers. Specific areas of focus include the role of SFN in the regulation of cell cycle, apoptosis, inflammation, antioxidant defense, and cancer cell signaling and their relationships to epigenetic mechanisms. Finally, remaining challenges and research needs for translating mechanistic work with SFN into human studies and clinical intervention trials are discussed.

The intake of broccoli sprouts modulates the inflammatory and vascular prostanoids but not the oxidative stress-related isoprostanes in healthy humans

Current evidence supports the positive association between the consumption of plant foods and health. In this work, we assessed the effect of consuming a half-serving (30 g) or one serving (60 g) of broccoli sprouts on the urinary concentrations of biomarkers of oxidative stress (isoprostanes) and inflammation (prostaglandins and thromboxanes). Twenty-four volunteers participated in the project. A quantitative determination of sulforaphane and its mercapturic derivatives, eicosanoids, and total vitamin C in urine was performed. The intake of broccoli sprouts produced an increase in the urinary concentrations of sulforaphane metabolites and vitamin C. Among the 13 eicosanoids analyzed, tetranor-PGEM and 11β-PGF2α as well as 11-dehydro-TXB2 showed a significant decrease in their urinary concentrations after the ingestion of broccoli sprouts. Therefore, the consumption of broccoli sprouts modulated the excretion of biomarkers linked to inflammation and vascular reactions without exerting a significant influence on the oxidation of phospholipids in vivo.

Self-report of fruit and vegetable intake that meets the 5 a day recommendation is associated with reduced levels of oxidative stress biomarkers and increased levels of antioxidant defense in premenopausal women

BACKGROUND

Oxidative stress has been associated with a variety of chronic diseases and reproductive disorders. Fruits and vegetables (F/V) may contribute to antioxidant vitamin and micronutrient levels and reduce oxidative stress.

OBJECTIVE

To investigate the effect of meeting the 5 A Day For Better Health Program recommendation for F/V consumption on biomarkers of oxidative damage and antioxidant defense.

DESIGN

In this longitudinal study, healthy premenopausal women (n=258) were followed for ≤2 menstrual cycles with ≤16 oxidative stress measures timed to cycle phase.

MAIN OUTCOME MEASURES

Plasma concentrations of F2-isoprostane, 9-hydroxyoctadecadieneoic acid, 13-hydroxyoctadecadieneoic acid, erythrocyte activity of superoxide dismutase, glutathione reductase, and glutathione peroxidase, as well as blood micronutrient concentrations were measured. Dietary intake was assessed by food frequency questionnaires (FFQs) (1 per cycle), and 24-hour recalls (≤4 per cycle).

STATISTICAL ANALYSES PERFORMED

Fruit and vegetable servings were dichotomized based on the recommendation to consume five servings of F/V each day. Linear mixed models with repeated measures were used to analyze lipid peroxidation markers, antioxidant vitamins, and antioxidant enzymes by cycle phase and in association with usual F/V intake.

RESULTS

For both 24-hour recall (timed to cycle phase) and cycle-specific FFQ, meeting the recommendation to consume five servings of F/V each day was associated with decreased F2-isoprostanes (24-hour recall β=-.10 [95% CI, -0.12 to -0.07]; FFQ β= -.14 [95% CI, -0.18 to -0.11]). Glutathione reductase was lower in association with typical consumption of five or more servings of F/V by FFQ but not in the phase-specific analysis. Higher levels of ascorbic acid, lutein, beta carotene, and beta cryptoxanthin were observed with both intake measures.

CONCLUSIONS

Meeting the 5 A Day For Better Health Program recommendation was associated with lower oxidative stress and improved antioxidant status in analyses of typical diet (via FFQ) and in menstrual cycle phase-specific analyses using 24-hour recalls. Green salads were commonly eaten and increasing intake of salads may be a useful strategy to influence oxidation in reproductive aged women.

Novel concepts of broccoli sulforaphanes and disease: induction of phase II antioxidant and detoxification enzymes by enhanced-glucoraphanin broccoli

Consumption of broccoli has long been considered to play a role in a healthy diet. Broccoli accumulates significant amounts of the phytonutrient glucoraphanin (4-methylsulfinylbutyl glucosinolate), which is metabolized in vivo to the biologically active sulforaphane. The preponderance of evidence available from in vitro, animal, and human studies supports the association of sulforaphane with phase II enzyme induction. This has provided impetus for developing varieties of broccoli, both sprouts and whole heads, that are rich in glucoraphanin. The cancer-preventive properties of cruciferous vegetables, especially broccoli, have been studied for decades. However, evidence of broccoli directly affecting cancer incidence or progression is ambiguous, in part because of the presence of substantial polymorphisms in enzymes that metabolize sulforaphane. Since broccoli sulforaphane is one of the most potent inducers of phase II enzymes, exploration into broccoli's impact on other areas of human health, such as cardiovascular health and upper airway immunity, has been suggested. This review provides an update on evidence supporting phase II enzyme induction by sulforaphanes, with implications for breeding broccoli varieties with enhanced amounts of glucoraphanin. Early-stage human studies of consumption of broccoli with enhanced glucoraphanin are also discussed.

Induction of phase 2 antioxidant enzymes by broccoli sulforaphane: perspectives in maintaining the antioxidant activity of vitamins a, C, and e

Consumption of fruits and vegetables is recognized as an important part of a healthy diet. Increased consumption of cruciferous vegetables in particular has been associated with a decreased risk of several degenerative and chronic diseases, including cardiovascular disease and certain cancers. Members of the cruciferous vegetable family, which includes broccoli, Brussels sprouts, cauliflower, and cabbage, accumulate significant concentrations of glucosinolates, which are metabolized in vivo to biologically active isothiocyanates (ITCs). The ITC sulforaphane, which is derived from glucoraphanin, has garnered particular interest as an indirect antioxidant due to its extraordinary ability to induce expression of several enzymes via the KEAP1/Nrf2/ARE pathway. Nrf2/ARE gene products are typically characterized as Phase II detoxification enzymes and/or antioxidant (AO) enzymes. Over the last decade, human clinical studies have begun to provide in vivo evidence of both Phase II and AO enzyme induction by SF. Many AO enzymes are redox cycling enzymes that maintain redox homeostasis and activity of free radical scavengers such as vitamins A, C, and E. In this review, we present the existing evidence for induction of PII and AO enzymes by SF, the interactions of SF-induced AO enzymes and proposed maintenance of the essential vitamins A, C, and E, and, finally, the current view of genotypic effects on ITC metabolism and AO enzyme induction and function.

Combined fruit and vegetable intake is correlated with improved inflammatory and oxidant status from a cross-sectional study in a community setting

Previous studies have examined the relationship between specific nutrient and food intakes with limited markers of either inflammation or oxidant status. The objective of this study was to determine if an increase in combined self-reported fruit and vegetable (F&V) intake in a community setting was associated with improved multiple markers of inflammatory and oxidant status. A community group (N = 1000, age 18-85 years, 61% female) gave two fasted blood samples separated by 12 weeks. Blood inflammatory biomarkers included total leukocytes (WBC), plasma C-reactive protein (CRP), interleukin-6 (IL-6), IL-10, tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1, and granulocyte colony stimulating factor. Measured oxidant status markers were ferric reducing ability of plasma (FRAP), oxygen radical absorbance capacity (ORAC) and plasma F₂-isoprostanes. The relation of markers across categories of F&V intake was examined. In analyses controlling for other important dietary and lifestyle factors, IL-6 and TNF-α were significantly lower across categories of increasing F&V intakes (p < 0.008). FRAP and ORAC were significantly higher (p < 0.0001 and p = 0.047 respectively) while F(2)-isoprostanes was significantly lower (p < 0.0001) across F&V categories. In a community study, several markers of both inflammation and oxidant status were associated in a putatively salutary direction by higher intake of combined F&V, supporting current guidelines suggesting increased F&V consumption for the prevention of chronic diseases.

Increasing the vegetable intake dose is associated with a rise in plasma carotenoids without modifying oxidative stress or inflammation in overweight or obese postmenopausal women

The optimal amount of vegetable consumption required to reduce chronic disease risk is widely debated. Intervention trials evaluating biological activity of vegetables at various doses are limited. We conducted a 3-dose, crossover feeding trial to test the hypothesis that vegetable intake is associated in a dose-dependent manner with increased plasma carotenoids and subsequently reduced oxidative stress and inflammation in 49 overweight, postmenopausal women. Participants were assigned in random order to 2 (130 g), 5 (287 g), and 10 (614 g) daily servings of fresh, greenhouse-grown vegetables for 3-wk intervals with a 4-wk washout period between treatments. Plasma total carotenoids significantly increased from 1.63 to 2.07 μmol/L with a dose of 2 vegetable servings, from 1.49 to 2.84 μmol/L with a dose of 5 vegetable servings, and from 1.40 to 4.42 μmol/L with a dose of 10 vegetable servings (pre-post paired ttests, all P < 0.001). The change during each feeding period increased with each dose level (P < 0.001). Urine concentrations of 8-isoprostane F2α, hexanoyl lysine, and serum high sensitivity C-reactive protein were not affected by any administered vegetable dose. In this variable-dose vegetable study, a dose-response for plasma carotenoids was demonstrated without significant change in oxidative stress and inflammation in overweight, postmenopausal women.

Cruciferous vegetable supplementation in a controlled diet study alters the serum peptidome in a GSTM1-genotype dependent manner

Background

Cruciferous vegetable intake is inversely associated with the risk of several cancers. Isothiocyanates (ITC) are hypothesized to be the major bioactive constituents contributing to these cancer-preventive effects. The polymorphic glutathione-S-transferase (GST) gene family encodes several enzymes which catalyze ITC degradation in vivo.

Methods

We utilized high throughput proteomics methods to examine how human serum peptides (the "peptidome") change in response to cruciferous vegetable feeding in individuals of different GSTM1 genotypes. In two randomized, crossover, controlled feeding studies (EAT and 2EAT) participants consumed a fruit- and vegetable-free basal diet and the basal diet supplemented with cruciferous vegetables. Serum samples collected at the end of the feeding period were fractionated and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry spectra were obtained. Peak identification/alignment computer algorithms and mixed effects models were used to analyze the data.

Results

After analysis of spectra from EAT participants, 24 distinct peaks showed statistically significant differences associated with cruciferous vegetable intake. Twenty of these peaks were driven by their GSTM1 genotype (i.e., GSTM1+ or GSTM1- null). When data from EAT and 2EAT participants were compared by joint processing of spectra to align a common set, 6 peaks showed consistent changes in both studies in a genotype-dependent manner. The peaks at 6700 m/z and 9565 m/z were identified as an isoform of transthyretin (TTR) and a fragment of zinc α2-glycoprotein (ZAG), respectively.

Conclusions

Cruciferous vegetable intake in GSTM1+ individuals led to changes in circulating levels of several peptides/proteins, including TTR and a fragment of ZAG. TTR is a known marker of nutritional status and ZAG is an adipokine that plays a role in lipid mobilization. The results of this study present evidence that the GSTM1-genotype modulates the physiological response to cruciferous vegetable intake.

Identification of the phenolic components of collard greens, kale, and Chinese broccoli

An LC-MS profiling method was used for a comprehensive study of the phenolic components of collard greens, kale, and Chinese broccoli, three Brassica green leafy vegetables. This study led to the identification of 45 flavonoids and 13 hydroxycinnamic acid derivatives in the three vegetables. Most of the identifications were based on comparison of compounds previously reported in the literature for Brassica vegetables. The results indicate that the three materials have very similar phenolic component profiles. For each, kaempferol glycosides and acylgentiobiosides were the major phenolic compounds, quercetin glycosides were minor compounds, and most of the flavononol glycosides existed in their acylated forms. In addition, each of the materials contained caffeoyl-, p-coumaroyl-, and feruloylquinic acid monomers with a 3-position derivative as the dominant isomer. This is the first report for most of these phenolics in collard greens and Chinese broccoli and for >20 of them in kale.

Food synergy: an operational concept for understanding nutrition

Research and practice in nutrition relate to food and its constituents, often as supplements. In food, however, the biological constituents are coordinated. We propose that "thinking food first"' results in more effective nutrition research and policy. The concept of food synergy provides the necessary theoretical underpinning. The evidence for health benefit appears stronger when put together in a synergistic dietary pattern than for individual foods or food constituents. A review of dietary supplementation suggests that although supplements may be beneficial in states of insufficiency, the safe middle ground for consumption likely is food. Also, food provides a buffer during absorption. Constituents delivered by foods taken directly from their biological environment may have different effects from those formulated through technologic processing, but either way health benefits are likely to be determined by the total diet. The concept of food synergy is based on the proposition that the interrelations between constituents in foods are significant. This significance is dependent on the balance between constituents within the food, how well the constituents survive digestion, and the extent to which they appear biologically active at the cellular level. Many examples are provided of superior effects of whole foods over their isolated constituents. The food synergy concept supports the idea of dietary variety and of selecting nutrient-rich foods. The more we understand about our own biology and that of plants and animals, the better we will be able to discern the combinations of foods, rather than supplements, which best promote health.

Plasma Carotenoids and Biomarkers of Oxidative Stress in Patients with prior Head and Neck Cancer

Diets high in fruits and vegetables are generally believed protective against several chronic diseases. One suggested mechanism is a reduction in oxidative stress. The carotenoids, nutrients found in colored fruits and vegetables, possess antioxidant properties in vitro, but their role in humans is less well documented. The aim of this cross-sectional study was to explore the relationships between the most abundant plasma carotenoids (alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and beta-cryptoxanthin), as well as grouped carotenoids (total xanthophylls, carotenes and carotenoids), and urinary excretion of the F(2)-isoprostanes (F(2)-IsoPs), stable and specific biomarkers of oxidative damage to lipids. Two F(2)-IsoP measures were utilized: total F(2)-IsoPs and 8-iso-PGF(2alpha). The study population (N = 52) was drawn from a study among patients curatively treated for early-stage head and neck cancer. Unadjusted linear regression analyses revealed significant inverse associations between plasma lutein, total xanthophylls and both F(2)-IsoP measures at baseline. After control for potential confounders, all individual and grouped xanthophylls remained inversely associated with the F(2)-IsoP measures, but none of these associations achieved significance. The carotenes were not inversely associated with total F(2)-IsoPs or 8-iso-PGF(2a) concentrations. The finding of consistent inverse associations between individual and grouped xanthophylls, but not individual and grouped carotenes, and F(2)-IsoPs is intriguing and warrants further investigation.

Chemomodulatory action of Foeniculum vulgare (Fennel) on skin and forestomach papillomagenesis, enzymes associated with xenobiotic metabolism and antioxidant status in murine model system

The chemopreventive effect of different doses of test diet of Foeniculum vulgare Mill (Fennel) seeds was examined on DMBA-induced skin and B(a)P-induced forestomach papillomagenesis in Swiss albino mice. To the best of our knowledge, this is the first report of Fennel seeds exhibiting a significant reduction in the skin and the forestomach tumor incidence and tumor multiplicity as compared to the control group. Further, biochemical assays showed a significant increase in the content/activities of phase I enzymes especially in the case of 6% test diet. A concomitant increase in the activities of the phase II enzymes were observed with all the doses of test diet under study. A significant enhancement in the activities of antioxidant enzymes were observed especially at 4% and 6% test diets of Fennel. Glyoxalase I activity and the content of reduced glutathione were significantly elevated. Expectedly, the levels of peroxidative damage along with lactate dehydrogenase activity, exhibited a significant reduction at all three doses of test diets. These findings were indicative of chemopreventive potential of Fennel against carcinogenesis.

Cruciferous vegetables, the GSTP1 Ile105Val genetic polymorphism, and breast cancer risk

BACKGROUND

Cruciferous vegetables are the primary source of isothiocyanates and other glucosinolate derivatives that are known to induce phase II detoxifying enzymes, including glutathione S-transferases (GSTs).

OBJECTIVE

We investigated the independent and combined effects of cruciferous vegetable intake and the GSTP1 Ile(105)Val genetic polymorphism on breast cancer risk.

DESIGN

Analyses included 3035 cases and 3037 population controls who were participating in the Shanghai Breast Cancer Study and for whom diet and genetic data were complete (87% of cases and 85% of controls).

RESULTS

With the use of multivariate logistic regression, the GSTP1 Val/Val genotype was significantly associated with greater breast cancer risk (OR = 1.50; 95% CI: 1.12, 1.99). The association was significantly greater in premenopausal women (OR = 1.69; 95% CI: 1.17, 2.43) than in postmenopausal women (OR = 1.20; 95% CI: 0.74, 1.92). Total cruciferous vegetable intake was not significantly associated with breast cancer risk, although subjects reporting greater turnip (P for trend < 0.001) and Chinese cabbage (P for trend = 0.049) intakes had a significantly lower postmenopausal breast cancer risk. Women with the GSTP1 Val/Val genotype and low cruciferous vegetable intake had a breast cancer risk 1.74-fold (95% CI: 1.13, 2.67) that of women with the Ile/Ile or Ile/Val genotype. This effect of low cruciferous vegetable intake and the Val/Val genotype was seen predominantly among premenopausal women (OR = 2.08; 95% CI = 1.20, 3.59).

CONCLUSIONS

Cruciferous vegetable intake consistent with high isothiocyanate exposure may reduce breast cancer risk. Cruciferous vegetable intake also may ameliorate the effects of the GSTP1 genotype.

Dietary fat subgroups, zinc, and vegetable components are related to urine F2a-isoprostane concentration, a measure of oxidative stress, in midlife women

Smoking, diet, and physical activity may impact chronic diseases in part by promoting or attenuating oxidative stress. We evaluated associations between lifestyle factors and urine F(2a)-isoprostanes, a marker of oxidative stress in 1610 participants of the Study of Women's Health Across the Nation (SWAN). Dietary intake and physical activity were assessed at baseline and the 5th year 05 (Y05). These data were related to Y05 urinary F(2a)-isoprostane concentration with regression analyses. Median urine F(2a)-isoprostane concentration was 433 ng/L overall, 917 ng/L in smokers [inter-quartile range (IQR): 467, 1832 ng/L], and 403 ng/L in nonsmokers (IQR: 228, 709 ng/L; P < 0.0001 for difference). Higher trans fat intake was associated with higher urine F(2a)-isoprostane concentration; partial Spearman correlations (rho(x|y)) between Y05 urine F(2a)-isoprostane concentration and trans fatty acids was 0.19 (P = 0.03) in smokers and 0.13 (P < 0.0001) in nonsmokers. Increased log trans fat intake from baseline to Y05 was associated with higher concentration of log urine F(2a)-isoprostanes in nonsmokers (beta = 0.131, SE = 0.04, P = 0.0003). In nonsmokers, the partial correlation (rho(x|y)) between lutein and urine F(2a)-isoprostane concentration was -0.13 (P < 0.0001). Increased intake of log lutein from baseline to Y05 was also associated with lower log urine F(2a)-isoprostane concentration (beta = -0.096, SE = 0.03, P = 0.0005) in nonsmokers. Increased zinc intake from baseline to Y05 was associated with lower log urine F(2a)-isoprostane concentration in smokers and nonsmokers (beta = -0.346, SE = 0.14, P = 0.01), and -0.117, 0.04 (P = 0.001), respectively]. In conclusion, diet (fat subtypes, zinc, and vegetable components) and smoking were associated with urine F(2a)-isoprostanes, a marker of oxidative stress.