Total and individual antioxidant intake and endometrial cancer risk: results from a population-based case-control study in New Jersey

Polyphenols Influence the Development of Endometrial Cancer by Modulating the Gut Microbiota

Dysbiosis of the microbiota in the gastrointestinal tract can induce the development of gynaecological tumours, particularly in postmenopausal women, by causing DNA damage and alterations in metabolite metabolism. Dysbiosis also complicates cancer treatment by influencing the body's immune response and disrupting the sensitivity to chemotherapy drugs. Therefore, it is crucial to maintain homeostasis in the gut microbiota through the effective use of food components that affect its structure. Recent studies have shown that polyphenols, which are likely to be the most important secondary metabolites produced by plants, exhibit prebiotic properties. They affect the structure of the gut microbiota and the synthesis of metabolites. In this review, we summarise the current state of knowledge, focusing on the impact of polyphenols on the development of gynaecological tumours, particularly endometrial cancer, and emphasising that polyphenol consumption leads to beneficial modifications in the structure of the gut microbiota.

Evaluation of The Antioxidant Capacity of Food Products: Methods, Applications and Limitations

Assays of total antioxidant capacity (TAC) are popular in the analysis of food products. This review presents the most popular assays of TAC and their limitations, databases of TAC of food products, their application in clinical studies, and the effect of processing on the TAC of food. The importance of sample preparation for TAC assays and striking effects of digestion in the gastrointestinal tract on the TAC of food are discussed. Critical opinions on the validity of food TAC assays are considered. It is concluded that TAC methods can be useful as screening assays for food quality control and as low-cost, high-throughput tools used to discover potential antioxidant sources and follow changes in the content of antioxidants during food processing. However, effects revealed by TAC assays should be followed and explained using more specific methods.

Antioxidative, Anti-Inflammatory, Anti-Obesogenic, and Antidiabetic Properties of Tea Polyphenols-The Positive Impact of Regular Tea Consumption as an Element of Prophylaxis and Pharmacotherapy Support in Endometrial Cancer

Endometrial cancer (EC) is second only to cervical carcinoma among the most commonly diagnosed malignant tumours of the female reproductive system. The available literature provides evidence for the involvement of 32 genes in the hereditary incidence of EC. The physiological markers of EC and coexisting diet-dependent maladies include antioxidative system disorders but also progressing inflammation; hence, the main forms of prophylaxis and pharmacotherapy ought to include a diet rich in substances aiding the organism’s response to this type of disorder, with a particular focus on ones suitable for lifelong consumption. Tea polyphenols satisfy those requirements due to their proven antioxidative, anti-inflammatory, anti-obesogenic, and antidiabetic properties. Practitioners ought to consider promoting tea consumption among individuals genetically predisposed for EC, particularly given its low cost, accessibility, confirmed health benefits, and above all, suitability for long-term consumption regardless of the patient’s age. The aim of this paper is to analyse the potential usability of tea as an element of prophylaxis and pharmacotherapy support in EC patients. The analysis is based on information available from worldwide literature published in the last 15 years.

An Assessment of Serum Selenium Concentration in Women with Endometrial Cancer

Background: Numerous studies have shown a relationship between low serum selenium levels and an increased risk of developing cancer. Methods: A total of 306 women participated in the study: 153 patients diagnosed with endometrial cancer and 153 healthy women who were matched, in terms of birth year (+/−3 years), to the patients from the study group. The quantitative measurement of selenium content in the collected blood samples was performed using a mass spectrometer with excitation in inductively coupled plasma. In order to determine the relationship between the risk factors and the incidence of endometrial cancer, analyses based on single- and multi-factor conditional logistic regression models were performed. Results: The mean concentration of selenium was lower in patients with endometrial cancer than in healthy controls (60.63 µg/L (0.77 µmol/L) vs. 78.74 µg/L (0.99 µmol/L), respectively). When compared in quartiles, a significant association of lower selenium concentration with the incidence of endometrial cancer was recorded. The highest OR was observed in the first and second quartiles (OR-22.0, p-value < 0.001; medium selenium level 46.95 µg/L (0.59 µmol/L), and OR-5.94; p-value < 0.001; medium selenium level 63.60 µg/L (0.80 µmol/L), respectively). Conclusion: A strong correlation between the level of selenium in the blood serum and the risk of endometrial cancer indicates that patients with low levels should be a candidate group requiring appropriate preventive examinations. Further research on a larger group of patients is required.

Review of Mendelian Randomization Studies on Endometrial Cancer

Endometrial cancer (EC) is a common gynecological cancer. In some parts of the world, the incidence and mortality of EC are on the rise. Understanding the risk factors of EC is necessary to prevent the occurrence of this disease. Observational studies have revealed the association between certain modifiable environmental risk factors and EC risk. However, due to unmeasured confounding, measurement errors, and reverse causality, observational studies sometimes have limited ability to judge robust causal inferences. In recent years, Mendelian randomization (MR) analysis has received extensive attention, providing valuable insights for cancer-related research, and is expected to identify potential therapeutic interventions. In MR analysis, genetic variation (alleles are randomly assigned during meiosis and are usually independent of environmental or lifestyle factors) is used instead of modifiable exposure to study the relationship between risk factors and disease. Therefore, MR analysis can make causal inference about exposure and disease risk. This review briefly describes the key principles and assumptions of MR analysis; summarizes published MR studies on EC; focuses on the correlation between different risk factors and EC risks; and discusses the application of MR methods in EC research. The results of MR studies on EC showed that type 2 diabetes, uterine fibroids, higher body mass index, higher plasminogen activator inhibitor-1 (PAI-1), higher fasting insulin, early insulin secretion, longer telomere length, higher testosterone and higher plasma cortisol levels are associated with increased risk of EC. In contrast, later age of menarche, higher circulatory tumor necrosis factor, higher low-density lipoprotein cholesterol, and higher sex hormone-binding globulin levels are associated with reduced risk of EC. In general, despite some limitations, MR analysis still provides an effective way to explore the causal relationship between different risk factors and EC.

Cryoconcentration by Centrifugation–Filtration: A Simultaneous, Efficient and Innovative Method to Increase Thermosensitive Bioactive Compounds of Aqueous Maqui (Aristotelia chilensis (Mol.) Stuntz) Extract

Maqui (Aristotelia chilensis (Mol.) Stuntz) is a Chilean berry rich in antioxidants, which are mostly found in the pulp and skin of the fruit. The objective was to evaluate the cryoconcentration process by centrifugation–filtration as a simultaneous, efficient, and innovative method to increase the content of thermosensitive bioactive compounds of aqueous maqui extract. Cryoconcentration separated the concentrated solute from the aqueous maqui extract with an efficiency of more than 95%; it increased the content of total polyphenols and total anthocyanins and antioxidant capacity by 280%, 573%, and 226%, respectively. Although the concentrates obtained by evaporation at 50, 70, and 80 °C increased the content of bioactive compounds, they did so in a lower percentage than the cryoconcentrate. Furthermore, cyanidin 3,5-diglucoside was degraded at 70 and 80 °C. In conclusion, cryoconcentration by centrifugation–filtration as a simultaneous process efficiently separates the solutes from the frozen matrix of aqueous maqui extract, and it maintains and increases the contents of polyphenols and anthocyanins and antioxidant capacity. This method is recommended for concentrating natural berry extracts with thermosensitive compounds.

Role of Vitamin E in Selected Malignant Neoplasms in Women

Vitamin E, which is actually a mixture of eight isoforms (four tocopherols and four tocotrienols), is a powerful antioxidant that protects polyunsaturated fatty acids against oxidation and has the ability to break the chain lipid peroxidation, which is used in the treatment of heart disease, atherosclerosis, muscle disorders or infertility among men. Studies in-vitro show that one of the effects of tocopherol is the reduction of cancer stem cell activity which is connected to poor clinical course. In the scientific literature, reports on the participation of vitamin E not only in protection against the mutagenic effects of reactive oxygen species, but also in its anti-angiogenic activity and the ability to inhibit the invasion and metastasis of neoplastic cells are increasingly common. In this context, the role of vitamin E in preventing the neoplastic process and selected malignant neoplasms among women seems to be of particular interest. In this article, we present the results of research on the potential anticancer effects of vitamin E in the fight against breast, cervical, endometrial and ovarian cancer.

Association of dietary total antioxidant capacity with anthropometric indicators, C-reactive protein, and clinical outcomes in hospitalized oncologic patients

OBJECTIVE

Many studies have shown an inverse association between higher dietary total antioxidant capacity (DTAC) and chronic non-communicable diseases, including cancer. The aim of this study was to evaluate the association of the DTAC with anthropometric and biochemical indicators and clinical outcomes in hospitalized patients with cancer.

METHODS

A cross-sectional study was carried out with 196 hospitalized patients diagnosed with cancer. The DTAC, determined by the ferric-reducing antioxidant power method, was calculated using a validated standard spreadsheet. Multivariate linear regression was used to assess the association, identifying anthropometric indicators that were associated with DTAC and the variables of interest. P < 0.05 was statistically significant.

RESULTS

The individuals included in the last tertile of DTAC presented lower occurrences of death (P = 0.032), constipation (P = 0.010), dysphagia (P = 0.010), painful swallowing and chewing (P = 0.019), and dehydration (P = 0.032) than individuals in the first tertile. The C-reactive protein values were significantly lower (P = 0.010) and handgrip strength values were higher (P = 0.037) in individuals in the third tertile than in the other participants.

CONCLUSIONS

DTAC was associated with a better prognosis of hospitalized cancer patients, considering signs and symptoms of nutritional impact, as well as the inflammatory state of the patients. These factors may influence the length of hospital stay and mortality. The findings of this research provide important information for a preventive and nutritional management perspective in this population.

Higher dietary total antioxidant capacity (TAC) reduces the risk of cardio-metabolic risk factors among adults: An updated systematic review and meta-analysis

Background: Numerous studies have revealed the protective role of dietary antioxidants against hypertension and diabetes. In the current systematic review and meta-analysis, we evaluated the possible role of dietary total antioxidant capacity (TAC) against metabolic parameters in the adult population. Methods: A literature search of authentic electronic resources including PubMed, Scopus, Web of Sciences, and Cochrane had been performed to retrieve the qualified observational studies that reported the mean plus/minus the SD for the parameter in subjects of the highest versus lowest dietary TAC categories up to July 2020. Results: Totally, the number of included studies was 13 for fasting blood sugar (FBS), 12 for systolic blood pressure (SBP), and 12 for diastolic blood pressure (DBP), with the participants' number of 26349. The results of the current study showed that being at highest category of TAC significantly reduces serum FBS (WMD: -2.381; CI: -3.445, -1.316; P<0.001), SBP (WMD: -1.080; CI: -1.458, -0.701; P<0.001) and DBP (WMD: -0.854; CI: -1.655, -0.052; P<0.001), while no significant difference in the serum insulin, HOMA-IR values, prevalence of type 2 diabetes (T₂DM) (P=0.37) and hypertension (HTN) (P=0.09) was observed. Subgroup analysis revealed the geographical location, dietary assessment tool, sample size, and gender as possible sources of heterogeneity. Conclusion: Higher intake of dietary TAC was associated with reduced SBP, DBP, and FBS in the current observational studies of this meta-analysis. These findings further confirm the clinical importance of dietary antioxidants in the prevention of different metabolic disorders.

A Narrative Review of the Role of Diet and Lifestyle Factors in the Development and Prevention of Endometrial Cancer

Simple Summary

The incidence and prevalence of endometrial cancer is increasing globally. The main factors involved in this increase have been the way women live today and what they eat and drink. In fact, the obesity pandemic that is sweeping across the planet is considered to be the main contributory feature. This review aims to introduce to a new audience, those that are not experts in the field, what is known about the different types of endometrial cancer and the mechanisms for their induction and protection. We also seek to summarise the existing knowledge on dietary and lifestyle factors that prevent endometrial development in susceptible populations and identify the main problem in this arena; the paucity of research studies and clinical trials that investigate the interaction(s) between diet, lifestyle and endometrial cancer risk whilst highlighting those areas of promise that should be further investigated.

Abstract

Endometrial cancer is the most common cancer affecting the reproductive organs of women living in higher-income countries. Apart from hormonal influences and genetic predisposition, obesity and metabolic syndrome are increasingly recognised as major factors in endometrial cancer risk, due to changes in lifestyle and diet, whereby high glycaemic index and lipid deposition are prevalent. This is especially true in countries where micronutrients, such as vitamins and minerals are exchanged for high calorific diets and a sedentary lifestyle. In this review, we will survey the currently known lifestyle factors, dietary requirements and hormonal changes that increase an individual’s risk for endometrial cancer and discuss their relevance for clinical management. We also examine the evidence that everyday factors and clinical interventions have on reducing that risk, such that informed healthy choices can be made. In this narrative review, we thus summarise the dietary and lifestyle factors that promote and prevent the incidence of endometrial cancer.

Antioxidant-Rich Diet, GSTP1 rs1871042 Polymorphism, and Gastric Cancer Risk in a Hospital-Based Case-Control Study

Background

Chronic gastritis along with Helicobacter pylori (H. pylori) infection has been implicated in inflammatory response-related genes linked to the causation of gastric cancer. Glutathione S-transferase Pi (GSTP1) plays a role in regulating oxidative stress and detoxification against carcinogenesis. In this study, we aimed to determine whether an antioxidant-rich diet is associated with gastric cancer risk and identify how this association could be altered by GSTP1 genetic variants.

Methods

This study included 1,245 participants (415 cases and 830 controls) matched for age and sex. The dietary antioxidant capacity was estimated based on the oxygen radical absorbance capacity (ORAC) incorporated with a semiquantitative food frequency questionnaire. Five single nucleotide polymorphisms (SNPs) of GSTP1 (rs1695, rs749174, rs1871042, rs4891, and rs947895) were selected among the exome array genotype data.

Results

High dietary ORAC was inversely associated with gastric cancer (hydrophilic ORAC OR _{T3vs. T1}, 95% CI = 0.57, 0.39–0.82, P = 0.004; lipophilic ORAC = 0.66, 0.45–0.95, P = 0.021; total phenolics = 0.57, 0.39–0.83, P = 0.005). The polymorphism rs1871042 increased the risk of gastric cancer (OR, 95% CI = 1.55, 1.10–2.16, P = 0.01, CT+TT vs. CC). A remarkably reduced risk of gastric cancer was observed among those who had a high dietary ORAC according to rs1871042 polymorphism (hydrophilic ORAC OR _{T3vs. T1}, 95% CI = 0.36, 0.17–0.78, P for trend = 0.013; lipophilic ORAC = 0.58, 0.37–0.93, P for trend = 0.021; total phenolics = 0.38, 0.17–0.83, P for trend = 0.019).

Conclusions

Our findings indicate that dietary ORAC intake may be inversely associated with the risk of gastric cancer altered by genetic variants of GSTP1, providing new intervention strategies for gastric cancer patients.

Phytochemicals in Gynecological Cancer Prevention

Gynecological cancer confers an enormous burden among women worldwide. Accumulating evidence points to the role of phytochemicals in preventing cervical, endometrial, and ovarian cancer. Experimental studies emphasize the chemopreventive and therapeutic potential of plant-derived substances by inhibiting the early stages of carcinogenesis or improving the efficacy of traditional chemotherapeutic agents. Moreover, a number of epidemiological studies have investigated associations between a plant-based diet and cancer risk. This literature review summarizes the current knowledge on the phytochemicals with proven antitumor activity, emphasizing their effectiveness and mechanism of action in gynecological cancer.

Twenty-five years of total antioxidant capacity measurement of foods and biological fluids: merits and limitations

This review summarises 25 years of investigations on antioxidants research in foods and biological fluids and critically analyses the merits and limitations of using the total antioxidant capacity (TAC) measurement in the metabolomic era. An enormous bulk of knowledge was produced regarding the antioxidant capacity of foods and large TAC databases were developed. A direct link between a food TAC value and any health benefit is erroneous and has led to several cases of consumer deception. However, the striking epidemiological evidence associating a high dietary TAC with some disease prevention and the availability of well-constructed TAC databases deserve attention and must be taken into account to establish the usefulness of measuring TAC in both foods and biological samples. The in vivo TAC measurement, usually performed in plasma, is influenced by many external factors, such as dietary habits, as well as environmental and behavioural factors, which are integrated towards homeostatic control by fine physiological mechanisms with high inter-individual variability. Therefore, plasma TAC cannot be considered as a unique biomarker of individual antioxidant status. However, the combined evaluation of plasma TAC with known markers of disease, individual metabolism, inflammation and genetics, as well as with markers of gut microbiota composition and activity, may lead to the identification of populations that are more responsive to food/diet TAC. In this framework, the appropriate use of TAC measurement both in food and in vivo can still provide support for the interpretation of complex phenomena and be a tool for sample screening when making a quick decision toward in-depth research investigations. © 2018 Society of Chemical Industry.

Circulating Interleukin-6 Level, Dietary Antioxidant Capacity, and Risk of Colorectal Cancer

Chronic inflammation is one of the causes of colorectal cancer (CRC), and circulating levels of inflammatory biomarkers have been linked to tumor promotion and progression. We aimed to evaluate the interleukin-6 (IL-6) level in CRC patients and determine whether a diet rich in antioxidants was associated with CRC. This study included 654 cases and 1312 controls matched for age and sex. We measured the plasma IL-6 concentration and estimated dietary antioxidant capacity based on oxygen radical absorbance capacity (ORAC) combined with a 106-item semiquantitative food frequency questionnaire. The IL-6 concentration was significantly increased in individuals with CRC (OR _{Q4 vs. Q1}, 95% CI = 6.23, 4.10-9.45, p < 0.001). High dietary ORAC showed an inverse association with CRC (total ORAC OR _{Q4 vs. Q1}, 95% CI = 0.26, 0.16-0.40, p < 0.001; total phenolics = 0.32, 0.21-0.50, p < 0.001). We found that low dietary ORAC was associated with a significant increase in CRC in the group with elevated IL-6 levels (total ORAC OR _{Q4 vs. Q1}, 95% CI = 4.34, 3.12-6.02, p < 0.001; total phenolics = 4.61, 3.33-6.39, p < 0.001). This study suggested an inverse association between dietary antioxidant capacity and IL-6 level among patients with CRC.

Artificial Intelligence Applied to Flavonoid Data in Food Matrices

Increasing interest in constituents and dietary supplements has created the need for more efficient use of this information in nutrition-related fields. The present work aims to obtain optimal models to predict the total antioxidant properties of food matrices, using available information on the amount and class of flavonoids present in vegetables. A new dataset using databases that collect the flavonoid content of selected foods has been created. Structural information was obtained using a structural-topological approach called TOPological Sub-Structural Molecular (TOPSMODE). Different artificial intelligence algorithms were applied, including Machine Learning (ML) methods. The study allowed us to demonstrate the effectiveness of the models using structural-topological characteristics of dietary flavonoids. The proposed models can be considered, without overfitting, effective in predicting new values of Oxygen Radical Absorption capacity (ORAC), except in the Multi-Layer Perceptron (MLP) algorithm. The best optimal model was obtained by the Random Forest (RF) algorithm. The in silico methodology we developed allows us to confirm the effectiveness of the obtained models, by introducing the new structural-topological attributes, as well as selecting those that most influence the class variable.

Primary Screening of Antioxidant Activity, Total Polyphenol Content, Carotenoid Content, and Nutritional Composition of 13 Edible Flowers from Japan

Thirteen edible flowers, which are used as food ingredients in Japan, were evaluated as possible sources of antioxidants and biological compounds. The nutritional composition, total polyphenol content (TPC), carotenoid content, and antioxidant activity of the edible flowers were determined based on the oxygen radical absorbance capacity (ORAC). Water was the main constituent of edible flowers, and carbohydrates were the primary macronutrients. The TPC of the edible flowers varied from 1.47 to 13.08 mg gallic acid equivalent/g fresh weight (FW). Carotenoids, including β-carotene and β-cryptoxanthin, were detected mainly in the edible flowers with petal colors ranging from yellow to orange, but especially in primula and cosmos yellow flowers, which have yellow petals. The ORAC value of the hydrophilic extract (HORAC) of edible flowers was higher than the ORAC value of the lipophilic extract (LORAC). The total antioxidant capacity (TAC) ranged from 33.03 to 320.36 μM Trolox equivalent/g FW. The highest TPC and TAC were observed in cosmos yellow flowers. On the basis of Pearson's correlation coefficient, the HORAC value and the TPC of the analyzed edible flowers were highly correlated (r=0.736). This preliminary study indicates that edible flowers are a potential source of antioxidants, and the addition of edible flowers to the human diet may be associated with health benefits.

Assessing the Role of Selenium in Endometrial Cancer Risk: A Mendelian Randomization Study

Endometrial cancer is the most commonly diagnosed gynecological cancer in developed countries. Based on evidence from observational studies which suggest selenium inhibits the development of several cancers (including lung and prostate cancer), selenium supplementation has been touted as a potential cancer preventative agent. However, randomized controlled trials have not reported benefit for selenium supplementation in reducing cancer risk. For endometrial cancer, limited observational studies have been conducted assessing whether selenium intake, or blood selenium levels, associated with reduced risk, and no randomized controlled trials have been conducted. We performed a two-sample Mendelian randomization analysis to examine the relationship between selenium levels (using a composite measure of blood and toenail selenium) and endometrial cancer risk, using summary statistics for four genetic variants associated with selenium levels at genome-wide significance levels (P < 5 × 10⁻⁸), from a study of 12,906 endometrial cancer cases and 108,979 controls, all of European ancestry. Inverse variance weighted (IVW) analysis indicated no evidence of a causal role for selenium levels in endometrial cancer development (OR per unit increase in selenium levels Z-score = 0.99, 95% CI = 0.87–1.14). Similar results were observed for sensitivity analyses robust to the presence of unknown pleiotropy (OR per unit increase in selenium levels Z-score = 0.98, 95% CI 0.89–1.08 for weighted median; OR per unit increase in selenium levels Z-score = 0.90, 95% CI = 0.53–1.50 for MR-Egger). In conclusion, these results do not support the use of selenium supplementation to prevent endometrial cancer.

Total antioxidant intake and prostate cancer in the Cancer of the Prostate in Sweden (CAPS) study. A case control study

Background

The total intake of dietary antioxidants may reduce prostate cancer risk but available data are sparse and the possible role of supplements unclear. We investigated the potential association between total and dietary antioxidant intake and prostate cancer in a Swedish population.

Methods

We used FFQ data from 1499 cases and 1112 controls in the population based case–control study Cancer of the Prostate in Sweden (CAPS). The ferric reducing antioxidant potential (FRAP) assay was used to assess the total antioxidant capacity (TAC) of diet and supplements. We calculated odds ratios (ORs) for the risk of prostate cancer across quintiles of antioxidant intake from all foods, from fruit and vegetables only, and from dietary supplements using unconditional logistic regression.

Results

Coffee comprised 62 % of the dietary antioxidant intake, tea 4 %, berries 4 %, chocolate 2 %, and boiled potatoes 2 %. In total 19 % and 13 % of the population took multivitamins and supplemental Vitamin C respectively, on a regular basis. Antioxidant intake from all foods and from fruits and vegetables separately measured by the FRAP assay was not associated with prostate cancer risk. For antioxidant intake from supplements we found a positive association with total, advanced, localized, high grade and low grade prostate cancer in those above median supplemental TAC intake of users compared to non-users (Adjusted ORs for total prostate cancer: 1.37, 95 % CI 1.08–1.73, advanced: 1.51, 95 % CI 1.11–2.06, localized: 1.36. 95 % CI 1.06–1.76, high grade 1.60, 95 % CI 1.06–2.40, low grade 1.36, 95 % CI 1.03–1.81). A high intake of coffee (≥6 cups/day) was associated with a possible risk reduction of fatal and significantly with reduced risk for high grade prostate cancer, adjusted OR: 0.45 (95 % CI: 0.22–0.90), whereas a high intake of chocolate was positively associated with risk of total, advanced, localized and low grade disease (adjusted OR for total: 1.43, 95 % CI 1.12–1.82, advanced: 1.40, 95 % CI 1.01–1.96, localized: 1.43, 95 % CI 1.08–1.88, low-grade: 1.41, 95 % CI 1.03–1.93).

Conclusions

Total antioxidant intake from diet was not associated with prostate cancer risk. Supplement use may be associated with greater risk of disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2486-8) contains supplementary material, which is available to authorized users.

Non-enzymatic antioxidant capacity and risk of gastric cancer

BACKGROUND

Consumption of fruit and vegetables has been inversely related to gastric cancer. Two studies found that dietary antioxidant capacity has some role in explaining this association. We investigated the overall antioxidant effect from diet on gastric cancer using three measures of non-enzymatic antioxidant capacity (NEAC).

METHODS

We used data from an Italian case-control study including 230 patients with incident, histologically confirmed gastric cancer, and 547 frequency matched controls admitted to the same hospitals for acute non-neoplastic diseases. A reproducible and valid food frequency questionnaire was used to assess subjects' usual diet. NEAC was measured using Italian food composition tables in terms of Trolox equivalent antioxidant capacity (TEAC), Ferric reducing-antioxidant power (FRAP) and Total radical-trapping antioxidant parameter (TRAP). We estimated the odds ratios (OR) of gastric cancer and the corresponding 95% confidence intervals (CI) using conditional logistic regression models including terms for recognized gastric cancer risk factors and total energy intake.

RESULTS

NEAC was inversely related with gastric cancer risk with ORs for the highest versus the lowest quintile of 0.54 (95%CI, 0.33-0.88) for TEAC, 0.67 (95%CI, 0.42-1.07) for FRAP and 0.57 (95%CI, 0.36-0.90) for TRAP.

CONCLUSIONS

A diet rich in antioxidant capacity reduced gastric cancer risk, suggesting a high consumption of fruit and vegetables and a moderate consumption of wine and whole cereals.

Antioxidants may not always be beneficial to health

Some results from cohort investigations indicate that supplemental antioxidants cannot decrease the risks for some diseases and even can play an inverse role because the antioxidant may not be involved in metabolism or may be a pro-oxidant in vivo. Therefore, further studies are required to identify conditions of an antioxidant converting into a pro-oxidant and the pathway of an antioxidant being a metabolic component. Additionally, long-term investigations on large-scale cohorts are required in order to clarify which disease is suitable for antioxidant therapy and how antioxidant intake can really maintain health.

Proanthocyanidins and other flavonoids in relation to endometrial cancer risk: a case-control study in Italy

Background:

Because of their antioxidant and antimutagenic properties, flavonoids may reduce cancer risk. Some flavonoids have antiestrogenic effects that can inhibit the growth and proliferation of endometrial cancer cells.

Methods:

In order to examine the relation between dietary flavonoids and endometrial cancer, we analysed data from an Italian case–control study including 454 incident, histologically confirmed endometrial cancers and 908 hospital-based controls. Information was collected through a validated food-frequency questionnaire. We applied data on food and beverage composition to estimate the intake of flavanols, flavanones, flavonols, anthocyanidins, flavones, isoflavones, and proanthocyanidins. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from multiple logistic regression models conditioned on age and study centre and adjusted for major confounding factors.

Results:

Women in the highest quartile category of proanthocyanidins with ⩾3 mers vs the first three quartile categories had an OR for endometrial cancer of 0.66 (95% CI=0.48–0.89). For no other class of flavonoids, a significant overall association was found. There was a suggestion of an inverse association for flavanones and isoflavones among women with body mass index <25 kg m⁻², and, for flavanones, among parous or non-users of hormone-replacement therapy women.

Conclusion:

High consumption of selected proanthocyanidins may reduce endometrial cancer risk.