Long-term dietary heme iron and red meat intake in relation to endometrial cancer risk

Exploring the potential role of ENPP2 in polycystic ovary syndrome and endometrial cancer through bioinformatic analysis

Background

Growing evidence indicates a significant correlation between polycystic ovary syndrome (PCOS) and endometrial carcinoma (EC); nevertheless, the fundamental molecular mechanisms involved continue to be unclear.

Methods

Initially, differential analysis, the least absolute shrinkage and selection operator (LASSO) regression, and support vector machine-recursive feature elimination (SVM-RFE) algorithms were employed to identify candidate genes associated with ferroptosis in PCOS. Subsequently, the TCGA-UCEC data were utilized to pinpoint the core gene. Then, the expression of ENPP2 in granulosa cells and endometrium of PCOS was validated using real-time PCR (RT-qPCR). Additionally, we investigated the role of ENPP2 in the progression from PCOS to EC through western blotting (WB), colony formation assay, cell scratch assay, transwell assay, and immunofluorescence (IF). Subsequently, ENPP2 gene set enrichment analysis (GSEA) analyses were conducted to identify common pathways involved in PCOS and EC, which were then verified by RT-qPCR. Finally, immune infiltration and the tumor microenvironment (TME) were explored to examine the involvement of ENPP2 in EC progression.

Results

The datasets TCGA-UCEC (pertaining to EC), GSE34526, GSE137684, and GSE6798 (related to PCOS) were procured and subjected to analysis. The gene ENPP2 has been recognized as the shared element connecting PCOS and EC. Next, we observed a significant downregulation of ENPP2 expression in the granulosa cells in PCOS compared to the normal patients, while an upregulation of ENPP2 expression was observed in the endometrium of hyperandrogenic PCOS patients relative to the normal. In vitro, the WB revealed that 5-dihydrotestosterone (DHT) upregulated ENPP2 expression in Ishikawa and HEC-1-A cells. Additionally, we found that ENPP2 promoted the proliferation, migration, and invasion of Ishikawa and HEC-1-A cells. Subsequently, we discovered that overexpressed ENPP2 may lead to an increase in CYP19A1 (aromatase) and AR mRNA level. IF demonstrated that ENPP2 increased the expression of AR, suggesting a regulatory role for ENPP2 in hormonal response within PCOS and EC. Our findings indicated a significant correlation between ENPP2 expression and the modulation of immune responses.

Micro- and Macronutrients in Endometrial Cancer-From Metallomic Analysis to Improvements in Treatment Strategies

Endometrial cancer is reported to be one of the most prevalent cancers of the female reproductive organs worldwide, with increasing incidence and mortality rates over the past decade. Early diagnosis is critical for effective treatment. Recently, there has been a growing focus on the role of nutrition and micronutrient and macronutrient status in patients with gynecologic cancers, including endometrial cancer. In the following paper, we have conducted an in-depth narrative literature review with the aim of evaluating the results of metallomic studies specifically concerning the micro- and macronutrient status of patients with endometrial cancer. The main objective of the paper was to analyze the results regarding the nutritional status of endometrial cancer patients and describe the role of chosen elements in the onset and progression of endometrial carcinogenesis. Further, we have focused on the evaluation of the usage of the described elements in the potential treatment of the abovementioned cancer, as well as the possible prevention of cancer considering proper supplementation of chosen elements in healthy individuals. Calcium supplementation has been proposed to reduce the risk of endometrial cancer, although some studies offer conflicting evidence. Deficiencies in phosphorus, selenium, and zinc have been inversely associated with endometrial cancer risk, suggesting they may play a protective role, whereas excessive levels of iron, copper, and cadmium have been positively correlated with increased risk. However, the molecular mechanisms by which these elements affect endometrial carcinogenesis are not fully understood, and current findings are often contradictory. Further research is needed to clarify these relationships and to evaluate the potential of nutritional interventions for the prevention and treatment of endometrial cancer.

Iron and cancer: overview of the evidence from population-based studies

Iron is an essential nutrient required for various physiological processes in the body. However, iron imbalance can potentially contribute to initiating and promoting cancer development. Epidemiological studies have investigated the relationship between dietary iron intake and the risk of different types of cancer, yet, not all studies have consistently shown a significant association between dietary iron and cancer risk. Also, studies have shown different effects of dietary heme and non-heme iron intake on cancer risk. While some epidemiological studies suggest a possible link between high dietary iron (mainly heme-iron) intake and increased cancer risk, the evidence remains inconsistent. Moreover, multiple iron biomarkers, which can mirror physiological iron status, have demonstrated varied correlations with the risk of cancer, contingent upon the specific biomarker analyzed and the type of cancer being investigated. Here, we have investigated the current evidence on the potential relationship between dietary iron intake on one hand, and iron biomarkers on the other hand, with the risk of developing different types of cancer, including breast, prostate, lung, pancreatic, colon, colorectal, and liver cancers. Further research is warranted to better understand the complex relationship between dietary iron, physiological iron and cancer development. Future research should account for factors that affect and interact with dietary iron and physiological iron levels, such as genetic susceptibility, overall diet quality, and lifestyle habits.

Cervicovaginal Metabolome and Tumor Characteristics for Endometrial Cancer Detection and Risk Stratification

PURPOSE

Endometrial cancer is highly prevalent and lacking noninvasive diagnostic techniques. Diagnosis depends on histological investigation of biopsy samples. Serum biomarkers for endometrial cancer have lacked sensitivity and specificity. The objective of this study was to investigate the cervicovaginal environment to improve the understanding of metabolic reprogramming related to endometrial cancer and identify potential biomarker candidates for noninvasive diagnostic and prognostic tests.

EXPERIMENTAL DESIGN

Cervicovaginal lavages were collected from 192 participants with endometrial cancer (n = 66) and non-malignant conditions (n = 108), and global untargeted metabolomics was performed. Using the metabolite data (n = 920), we completed a multivariate biomarker discovery analysis.

RESULTS

We analyzed grade 1/2 endometrioid carcinoma (n = 53) and other endometrial cancer subtypes (n = 13) to identify shared and unique metabolic signatures between the subtypes. When compared to non-malignant conditions, downregulation of proline (P < 0.0001), tryptophan (P < 0.0001), and glutamate (P < 0.0001) was found among both endometrial cancer groups, relating to key hallmarks of cancer including immune suppression and redox balance. Upregulation (q < 0.05) of sphingolipids, fatty acids, and glycerophospholipids was observed in endometrial cancer in a type-specific manner. Furthermore, cervicovaginal metabolites related to tumor characteristics, including tumor size and myometrial invasion.

CONCLUSIONS

Our findings provide insights into understanding the endometrial cancer metabolic landscape and improvement in diagnosis. The metabolic dysregulation described in this article linked specific metabolites and pathophysiological mechanisms including cellular proliferation, energy supply, and invasion of neighboring tissues. Furthermore, cervicovaginal metabolite levels related to tumor characteristics, which are used for risk stratification. Overall, development of noninvasive diagnostics can improve both the acceptability and accessibility of diagnosis.

Substitutions of saturated fat intakes with other macronutrients and foods and risk of NAFLD cirrhosis and all-cause hepatocellular carcinoma: a prospective cohort study

BACKGROUND

Short-term trials have shown a reduction in liver fat when saturated fatty acids (SFAs) are substituted with polyunsaturated fatty acids (PUFA), or with low-glycemic carbohydrates. However, few cohort studies have been conducted to investigate the associations of replacing SFA and SFA-rich foods with different macronutrients and foods in more severe stages of liver disease; nonalcoholic fatty liver disease (NAFLD) cirrhosis and hepatocellular carcinoma (HCC).

OBJECTIVES

To investigate associations between the substitution of SFA and SFA-rich foods with other macronutrients and foods and NAFLD cirrhosis and HCC in a middle-aged to elderly Swedish population of n = 77,059 males and females.

METHODS

Time-to-event analyses were performed to investigate associations between the food and macronutrient substitutions and NAFLD cirrhosis and HCC. Multivariable Cox regression models were constructed to estimate hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). Statistical isocaloric and equal-mass substitutions were performed using the leave-one-out method. Prespecified nutrient and food substitutions of interest were SFA with carbohydrates, SFA with fiber, SFA with PUFA, butter with margarine and vegetable oils, unprocessed red meat with fish, and milk with fermented milk.

RESULTS

Over a median follow-up of 24 y, 566 cases of NAFLD cirrhosis and 205 cases of HCC were registered. Overall, dietary substitutions showed no clear associations with either NAFLD cirrhosis or HCC. Substituting SFA with carbohydrates showed an HR of 0.87 (95% CI: 0.74, 1.02) for HCC and 1.00 (95% CI: 0.89, 1.11) for NAFLD cirrhosis. Substituting milk with fermented milk showed an HR of 0.93 (95% CI: 0.85, 1.01) for HCC and 0.97 (95% CI: 0.92, 1.03) for NAFLD cirrhosis.

CONCLUSIONS

No clear associations were observed between diet and NAFLD cirrhosis or HCC. Although accompanied by low precision, possible lowered risks of HCC by substituting SFA with carbohydrates or milk with fermented milk might be of interest, but needs replication in other cohorts.

Hypothetical 22-Year Intervention With the Dietary Approaches to Stop Hypertension and Risk of Heart Failure in a General Population

We used design principles of target trial methodology to emulate the effect of sustained adherence to the Dietary Approaches to Stop Hypertension (DASH) diet on the 22-year risk of heart failure. Women and men aged 45-83 years without previous heart failure, who answered questionnaires in 1997 from the Swedish Mammography Cohort and the Cohort of Swedish Men, were eligible. Follow-up questionnaires were sent in 2008-2009. Incidence of heart failure was ascertained using the Swedish Patient Register, updated until December 31, 2019. The parametric g-formula was used to estimate the 22-year risk of heart failure under sustained adherence to a population-adapted DASH diet compared with no intervention. Intakes before 1997 for before-baseline adjustment was available only for women. In total, 31,238 women and 34,939 men were eligible. The 22-year risk of heart failure was 14.5% with long-term adherence to the DASH diet compared with 15.2% with no intervention (risk difference = -0.7%, 95% confidence interval: 1.6, 0.0%) in women and correspondingly in men 15.3% vs. 16.2% (risk difference = -0.9%, 95% confidence interval: -1.6, -0.2%). Our hypothetical intervention suggests that sustained adherence to the population-adapted DASH diet may reduce risk of heart failure in middle-aged and elderly Swedish women and men.

Assessment of Serum Zn, Cu, Mn, and Fe Concentration in Women with Endometrial Cancer and Different Endometrial Pathologies

BACKGROUND

There is conflicting evidence on the effect of specific micronutrient concentration and cancer risk. In this study, we investigated the differences in serum zinc, copper, iron, and manganese levels and different endometrial pathologies, including endometrial cancer.

METHODS

110 patients with a confirmed diagnosis of endometrial cancer, benign uterine conditions (endometrial polyp, endometrial hyperplasia, uterine myoma), or normal endometrium were included in the study and assessed in terms of endometrial cancer risk factors. The measurements of serum micronutrients were conducted using inductively coupled plasma optical emission spectrometry.

RESULTS

When assessing for differences between serum concentrations of trace metals, we found significant differences in the distribution of Mn (p < 0.001) and Fe (0.034). There was also a significant difference in Cu/Zn ratio between the analyzed groups (p = 0.002). Patients' BMI was found to influence Cu concentration, with obese patients having higher mean copper concentration (p = 0.006). Also, patients' menopausal status was shown to influence Cu concentration with postmenopausal patients having higher Cu levels (p = 0.001). The menopausal status was found to influence Cu/Zn ratio (p = 0.002). Univariable regression analysis did not confirm that any of the micronutrients significantly influence the risk of endometrial cancer.

CONCLUSION

The concentration of specific trace metals varies between different histopathological diagnoses of endometrial pathologies. Menopausal status and patient BMI are endometrial cancer risk factors impacted by the concentrations of Cu and Zn and their ratio.

The Role of Iron and Cobalt in Gynecological Diseases

Iron and cobalt are micronutrients that play an important role in the regulation of cellular processes, being part of the centre of catalases, peroxidases, cytochromes and metalloproteins such as hemoglobin and myoglobin (Fe). Cobalt primarily functions as a component of hydroxycobalamin, which is essential for regulating red blood cell production. Maintaining normal levels of cobalt and iron in the human body is important, as a deficiency can lead to anaemia. These elements are also involved in reactions during which oxidative stress occurs and are therefore considered to be a cause of tumor formation. This paper will discuss aspects of the influence of cobalt and iron on mechanisms that may contribute to the growth of gynecological tumors, as well as other obstetric-gynecological disease entities, by altering the conditions of the microenvironment. In addition, the following review also highlights the role of cobalt and iron in the treatment of gynecological tumors.

Ferroptosis: Opportunities and Challenges in Treating Endometrial Cancer

Ferroptosis, a new way of cell death, is involved in many cancers. A growing number of studies have focused on the unique role of ferroptosis on endometrial cancer. In this study, we made a comprehensive review of the relevant articles published to get deep insights in the association of ferroptosis with endometrial cancer and to present a summary of the roles of different ferroptosis-associated genes. Accordingly, we made an evaluation of the relationships between the ferroptosis-associated genes and TNM stage, tumor grade, histological type, primary therapy outcome, invasion and recurrence of tumor, and accessing the different prognosis molecular typing based on ferroptosis-associated genes. In addition, we presented an introduction of the common drugs, which targeted ferroptosis in endometrial cancer. In so doing, we clarified the opportunities and challenges of ferroptosis activator application in treating endometrial cancer, with a view to provide a novel approach to the disease.

Drinking Water Disinfection Byproducts, Ingested Nitrate, and Risk of Endometrial Cancer in Postmenopausal Women

BACKGROUND

Disinfection byproducts (DBPs) and N-nitroso compounds (NOC), formed endogenously after nitrate ingestion, are suspected endometrial carcinogens, but epidemiological studies are limited.

OBJECTIVES

We investigated the relationship of these exposures with endometrial cancer risk in a large prospective cohort.

METHODS

Among postmenopausal women in the Iowa Women's Health Study cohort, we evaluated two major classes of DBPs, total trihalomethanes (TTHM) and five haloacetic acids (HAA5), and nitrate-nitrogen (NO3-N) in public water supplies (PWS) in relation to incident primary endometrial cancer (1986-2014). For women using their PWS >10y at enrollment (n=10,501; cases=261), we computed historical averages of annual concentrations; exposures were categorized into quantiles and when possible ≥95th percentile. We also computed years of PWS use above one-half the U.S. maximum contaminant level (>½ MCL; 40μg/L TTHM; 30μg/L HAA5; 5mg/L NO3-N). Dietary nitrate/nitrite intakes were estimated from a food frequency questionnaire. We estimated hazard ratios (HR) and 95% confidence intervals (CI) via Cox models adjusted for age, endometrial cancer risk factors [e.g., body mass index, hormone replacement therapy (HRT)], and mutually adjusted for DBPs or NO3-N. We evaluated associations for low-grade (cases=99) vs. high-grade (cases=114) type I tumors. We assessed interactions between exposures and endometrial cancer risk factors and dietary factors influencing NOC formation.

RESULTS

Higher average concentrations of DBPs (95th percentile: TTHM ≥93μg/L, HAA5 ≥49μg/L) were associated with endometrial cancer risk (TTHM: HR95vsQ1=2.19, 95% CI: 1.41, 3.40; HAA5: HR95vsQ1=1.84, 95% CI: 1.19, 2.83; ptrend<0.01). Associations were similarly observed for women greater than median years of PWS use with levels >½ MCL, in comparison with zero years (TTHM: HR36+vs0y=1.61, 95% CI: 1.18, 2.21; HAA5: HR38+vs0y=1.85, 95% CI: 1.31, 2.62). Associations with DBPs appeared stronger for low-grade tumors (TTHM: HRQ4vsQ1=2.12, 95% CI: 1.17, 3.83; p-trend=0.008) than for high-grade tumors (TTHM: HRQ4vsQ1=1.40, 95% CI: 0.80, 2.44; p-trend=0.339), but differences were not statistically significant (p-heterogeneity=0.43). Associations with TTHM were stronger among ever HRT users than non-HRT users (p-interaction<0.01). We observed no associations with NO3-N in drinking water or diet.

DISCUSSION

We report novel associations between the highest DBP levels and endometrial cancer for our Iowa cohort that warrant future evaluation. https://doi.org/10.1289/EHP10207.

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.

The Dietary Approach to Stop Hypertension (DASH) diet is associated with a lower risk of heart failure: A cohort study

AIMS

Trials demonstrate that following the DASH diet lowers blood pressure, which may prevent development of heart failure (HF). We investigated the association between long-term adherence to the DASH diet and food substitutions within the DASH diet on the risk of HF.

METHODS

Men and women aged 45-83 years without previous HF, ischemic heart disease or cancer at baseline in 1998 from the Cohort of Swedish Men (n = 41,118) and the Swedish Mammography Cohort (n = 35,004) were studied. The DASH diet emphasizes intake of fruit, vegetables, whole grains, nuts and legumes and low-fat dairy and deemphasizes red and processed meat, sugar-sweetened beverages and sodium. DASH diet scores were calculated based on diet assessed by food frequency questionnaires in late 1997 and 2009. Incidence of HF was ascertained using the Swedish Patient Register. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

During the median 22 years of follow-up (1998-2019) 12,164 participants developed HF. Those with the greatest adherence to the DASH diet had a lower risk of HF compared to those with the lowest adherence (HR 0.85, 95% CI 0.80, 0.91 for baseline diet and HR 0.83, 95% CI 0.78, 0.89 for long-term diet, comparing quintiles). Replacing 1 serving/day of red and processed meat with emphasized DASH diet foods was associated with an 8-12% lower risk of HF.

CONCLUSION

Long-term adherence to the DASH diet and relevant food substitutions within the DASH diet were associated with a lower risk of HF.

The relationship between processed meat, red meat, and risk of types of cancer: A Mendelian randomization study

Background

Observational studies have suggested processed and red meat may increase the risk of cancer. However, the causal effects and direction between them were still unclear. We conducted two-sample Mendelian randomization (MR) analysis to evaluate the causal effect of processed meat and red meat on the risk of nine common types of cancer, namely, lung, ovarian, endometrial, breast, kidney, gastric, prostate, skin, and oropharyngeal cancer.

Methods

Genome-wide association studies (GWAS) for processed meat and red meat (pork, beef, and mutton) were obtained from the UK Biobank. GWAS of types of cancer in this study were extracted from the genetic consortia and the FinnGen consortium. The inverse variance weighted (IVW) was carried out as the main method for two-sample MR analysis. Sensitivity analyses were used to assess the robustness of the results.

Results

Genetically predicted processed meat intake was causally associated with increased risk of lung cancer (OR [odds ratio] = 1.923, 95% CI = 1.084-3.409, P = 0.025). There is no convincing evidence for the associations between genetically determined processed meat, red meat, and the risk of other cancers we studied.

Conclusion

Our results suggested that intake of processed meat may increase the risk of lung cancer. These findings provided no evidence to support that consumption of processed and red meat has a large effect on the risk of other cancers we studied. Further research is needed to clarify the results.

Nrf2 Is a Potential Modulator for Orchestrating Iron Homeostasis and Redox Balance in Cancer Cells

Iron is an essential trace mineral element in almost all living cells and organisms. However, cellular iron metabolism pathways are disturbed in most cancer cell types. Cancer cells have a high demand of iron. To maintain rapid growth and proliferation, cancer cells absorb large amounts of iron by altering expression of iron metabolism related proteins. However, iron can catalyze the production of reactive oxygen species (ROS) through Fenton reaction. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important player in the resistance to oxidative damage by inducing the transcription of antioxidant genes. Aberrant activation of Nrf2 is observed in most cancer cell types. It has been revealed that the over-activation of Nrf2 promotes cell proliferation, suppresses cell apoptosis, enhances the self-renewal capability of cancer stem cells, and even increases the chemoresistance and radioresistance of cancer cells. Recently, several genes involving cellular iron homeostasis are identified under the control of Nrf2. Since cancer cells require amounts of iron and Nrf2 plays pivotal roles in oxidative defense and iron metabolism, it is highly probable that Nrf2 is a potential modulator orchestrating iron homeostasis and redox balance in cancer cells. In this hypothesis, we summarize the recent findings of the role of iron and Nrf2 in cancer cells and demonstrate how Nrf2 balances the oxidative stress induced by iron through regulating antioxidant enzymes and iron metabolism. This hypothesis provides new insights into the role of Nrf2 in cancer progression. Since ferroptosis is dependent on lipid peroxide and iron accumulation, Nrf2 inhibition may dramatically increase sensitivity to ferroptosis. The combination of Nrf2 inhibitors with ferroptosis inducers may exert greater efficacy on cancer therapy.

Consumption of red meat and processed meat and cancer incidence: a systematic review and meta-analysis of prospective studies

Red meat and processed meat consumption has been hypothesized to increase risk of cancer, but the evidence is inconsistent. We performed a systematic review and meta-analysis of prospective studies to summarize the evidence of associations between consumption of red meat (unprocessed), processed meat, and total red and processed meat with the incidence of various cancer types. We searched in MEDLINE and EMBASE databases through December 2020. Using a random-effect meta-analysis, we calculated the pooled relative risk (RR) and 95% confidence intervals (CI) of the highest versus the lowest category of red meat, processed meat, and total red and processed meat consumption in relation to incidence of various cancers. We identified 148 published articles. Red meat consumption was significantly associated with greater risk of breast cancer (RR = 1.09; 95% CI = 1.03-1.15), endometrial cancer (RR = 1.25; 95% CI = 1.01-1.56), colorectal cancer (RR = 1.10; 95% CI = 1.03-1.17), colon cancer (RR = 1.17; 95% CI = 1.09-1.25), rectal cancer (RR = 1.22; 95% CI = 1.01-1.46), lung cancer (RR = 1.26; 95% CI = 1.09-1.44), and hepatocellular carcinoma (RR = 1.22; 95% CI = 1.01-1.46). Processed meat consumption was significantly associated with a 6% greater breast cancer risk, an 18% greater colorectal cancer risk, a 21% greater colon cancer risk, a 22% greater rectal cancer risk, and a 12% greater lung cancer risk. Total red and processed meat consumption was significantly associated with greater risk of colorectal cancer (RR = 1.17; 95% CI = 1.08-1.26), colon cancer (RR = 1.21; 95% CI = 1.09-1.34), rectal cancer (RR = 1.26; 95% CI = 1.09-1.45), lung cancer (RR = 1.20; 95% CI = 1.09-1.33), and renal cell cancer (RR = 1.19; 95% CI = 1.04-1.37). This comprehensive systematic review and meta-analysis study showed that high red meat intake was positively associated with risk of breast cancer, endometrial cancer, colorectal cancer, colon cancer, rectal cancer, lung cancer, and hepatocellular carcinoma, and high processed meat intake was positively associated with risk of breast, colorectal, colon, rectal, and lung cancers. Higher risk of colorectal, colon, rectal, lung, and renal cell cancers were also observed with high total red and processed meat consumption.

Unintended Consequences: Nutritional Impact and Potential Pitfalls of Switching from Animal- to Plant-Based Foods

Consumers are shifting towards plant-based diets, driven by both environmental and health reasons. This has led to the development of new plant-based meat alternatives (PBMAs) that are marketed as being sustainable and good for health. However, it remains unclear whether these novel PBMAs to replace animal foods carry the same established nutritional benefits as traditional plant-based diets based on pulses, legumes and vegetables. We modelled a reference omnivore diet using NHANES 2017–2018 data and compared it to diets that substituted animal products in the reference diet with either traditional or novel plant-based foods to create flexitarian, vegetarian and vegan diets matched for calories and macronutrients. With the exception of the traditional vegan diet, all diets with traditional plant-based substitutes met daily requirements for calcium, potassium, magnesium, phosphorus, zinc, iron and Vitamin B12 and were lower in saturated fat, sodium and sugar than the reference diet. Diets based on novel plant-based substitutes were below daily requirements for calcium, potassium, magnesium, zinc and Vitamin B12 and exceeded the reference diet for saturated fat, sodium and sugar. Much of the recent focus has been on protein quality and quantity, but our case study highlights the risk of unintentionally increasing undesirable nutrients while reducing the overall nutrient density of the diet when less healthy plant-based substitutes are selected. Opportunities exist for PBMA producers to enhance the nutrient profile and diversify the format of future plant-based foods that are marketed as healthy, sustainable alternatives to animal-based products.

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.

Dietary iron and vitamins in association with mortality

BACKGROUND & AIMS

Although disorders of iron metabolism are among the most common diseases and dietary intakes of vitamin A, B₂, B₆, C, E, and folic acid are known to affect the absorption or oxidation of iron, limited data are available on the association of dietary iron and these vitamins with mortality in the same population. Specifically, the holistic dietary vitamins intake and its combined effect with iron on mortality are unclear. The purpose of this study was to evaluate the association of dietary iron, holistic dietary vitamins, and their interactive effect with total and cause-specific mortality.

METHODS

We evaluated the effects of dietary total/heme/non-heme iron, vitamins, and their interaction on all-cause/cardiovascular disease (CVD)/cancer mortality among 14,826 US adults in the National Health and Nutrition Examination Survey (NHANES), a population-based nationally representative study. We developed a vitamin score to represent the holistic dietary intakes of vitamin A, B₂, B₆, C, E, and folic acid.

RESULTS

A total of 2154 deaths occurred during a median follow-up of 9.3 years. Results from multivariate Cox proportional hazards models showed that higher vitamin score was associated lower risk of all-cause mortality (P-trend = 0.027). Negative interactions between dietary heme iron and vitamin score were observed on all-cause/CVD mortality. Dietary higher vitamins combined with lower heme iron was associated with lower risk of all-cause and CVD mortality (HR (95% confidence intervals (CIs)): 0.80 (0.64-0.98) and 0.55 (0.31-0.98), respectively). Higher dietary vitamins combined with higher total/non-heme iron was associated with lower risk of CVD mortality (HR (95%CIs): 0.69 (0.48-0.99) and 0.70 (0.48-0.99), respectively). These results remained significant even excluding participants with iron supplementation.

CONCLUSION

Our findings suggested that interactive effect of holistic dietary vitamins and iron play a protective role in decreasing all-cause and CVD mortality. Future studies, including cohort studies and clinical trials, are necessary to confirm these findings.

The Multifaceted Role of Heme in Cancer

Heme, an iron-containing porphyrin, is of vital importance for cells due to its involvement in several biological processes, including oxygen transport, energy production and drug metabolism. Besides these vital functions, heme also bears toxic properties and, therefore, the amount of heme inside the cells must be tightly regulated. Similarly, heme intake from dietary sources is strictly controlled to meet body requirements. The multifaceted nature of heme renders it a best candidate molecule exploited/controlled by tumor cells in order to modulate their energetic metabolism, to interact with the microenvironment and to sustain proliferation and survival. The present review summarizes the literature on heme and cancer, emphasizing the importance to consider heme as a prominent player in different aspects of tumor onset and progression.

The relation of healthy and Western dietary patterns to the risk of endometrial and ovarian cancers: a systematic review and meta-analysis

Dietary patterns have been used to explore the association between dietary factors and risk of endometrial (EC) and ovarian cancer (OC); however, the results are inconclusive. This meta-analysis aimed to analyze these associations. Methods: Pertinent studies published prior to March 2016 were systematically searched. The common dietary patterns were selected and adjusted risk estimates were derived by comparing the highest with the lowest categories of dietary pattern scores. Results: A total of 8 studies, 5 for endometrial cancer (1 cohort and 4 case-control studies including 2617 cases and 78082 participants/controls) and 3 for ovarian cancer (1 cohort and 2 case-control studies with 2025 cases and 101482 participants/controls) were included in this meta-analysis. A lower risk of EC was shown for the highest compared with the lowest category of the healthy dietary pattern (OR = 0.84, 95% CI: 0.72-0.98; P for heterogeneity = 0.10), whereas the Western dietary pattern was related to the higher risk of EC (OR = 1.19, 95% CI: 1.01-1.41; P for heterogeneity = 0.35). No significant relationship was found between the healthy dietary pattern (OR = 1.03, 95% CI: 0.69-1.53; P for heterogeneity = 0.01) and OC, while, adherence to the western pattern was associated with a 73% higher risk of OC (OR = 1.73, 95% CI: 1.08-2.37; P for heterogeneity = 0.06). Conclusion: A Western dietary pattern might be associated with a higher risk of endometrial and ovarian cancer.

Identification of Metabolomic Biomarkers for Endometrial Cancer and Its Recurrence after Surgery in Postmenopausal Women

Endometrial cancer (EC) is the most frequent gynecological cancer in developed countries. Most EC occurs after menopause and is diagnosed as endometrioid (type I) carcinomas, which exhibit a favorable prognosis. In contrast, non-endometrioid (type II) carcinomas such as serous tumors have a poor prognosis. Our goal was to identify novel blood-based markers associated with EC subtypes and recurrence after surgery in postmenopausal women. Using mass spectrometry-based untargeted metabolomics, we examined preoperative serum metabolites among control women (n = 18) and those with non-recurrent (NR) and recurrent (R) cases of type I endometrioid (n = 24) and type II serous (n = 12) carcinomas. R and NR cases were similar with respect to pathological characteristics, body mass index, and age. A total of 1,592 compounds were analyzed including 14 different lipid classes. When we compared EC cases with controls, 137 metabolites were significantly different. A combination of spermine and isovalerate resulted in an age-adjusted area under the receiver-operating characteristic curve (AUC_adj) of 0.914 (P < 0.001) for EC detection. The combination of 2-oleoylglycerol and TAG42:2-FA12:0 allowed the distinction of R cases from NR cases with an AUC_adj of 0.901 (P < 0.001). Type I R cases were also characterized by much lower levels of bile acids and elevated concentrations of phosphorylated fibrinogen cleavage peptide, whereas type II R cases displayed higher levels of ceramides. The findings from our pilot study provide a detailed metabolomics study of EC and identify putative serum biomarkers for defining clinically relevant risk groups.

Effects of pharmacological ascorbate on hemoglobin-induced cancer cell proliferation

The high heme content in red meat is associated with an increased risk of developing cancer. Pharmacologic concentrations of ascorbate can specifically kill a wide range of cancer cells. In this study, the impact of ascorbate at pharmacologic concentrations on hemoglobin (Hb)-modulated human hepatoma HepG2 cell survival was investigated. It was found that HepG2 cells were proliferated by Hb (5-25μM), but killed by high pharmacologic concentrations of ascorbate (2-10mM). Although ascorbate at the low pharmacologic concentration (0.5mM) alone exhibited insignificant effect on cell viability, it effectively inhibited Hb (10μM)-induced cancer cell proliferation. The mechanism of this cytotoxicity was based on the production of extracellular H₂O₂ and involved transition iron. The influence of ascorbate on Hb-dependent redox reactions (i.e. the oxidative stability of Hb and its cytotoxic ferryl intermediate) was further investigated to illustrate the reaction mechanism of ascorbate toxicity, where H₂O₂ was generated in the reaction of ascorbate with Hb. Furthermore, circular dichroism demonstrated no significant change in the secondary structure of Hb after ascorbate addition and molecular docking revealed binding modes of ascorbate with Hb. These results demonstrated that ascorbate could possess anti-cancer activity through interfering in Hb-dependent redox reactions.

Dietary patterns and endometrial cancer risk in the California Teachers Study cohort

PURPOSE

Information on the role of dietary patterns and endometrial cancer risk is limited. We investigated whether dietary patterns are associated with endometrial cancer risk among women in the California Teachers Study cohort.

METHODS

Among 75,093 eligible women, 937 developed invasive endometrial cancer between 1995 and 2011. Multivariate Cox regression was performed to estimate relative risks (RR) and 95% confidence intervals (CI) associated with five dietary patterns identified by principal components factor analysis: "plant-based," "high protein/high fat," "high carbohydrates," "ethnic," and "salad and wine."

RESULTS

These dietary patterns were not associated with endometrial cancer risk overall (RR = 0.91, 95% CI: 0.72, 1.15 for the highest vs. lowest quintile of the "plant-based" dietary pattern) or by menopausal status and hormone therapy use.

CONCLUSIONS

Dietary patterns do not seem to be associated with endometrial cancer risk.

Heme, an essential nutrient from dietary proteins, critically impacts diverse physiological and pathological processes

Heme constitutes 95% of functional iron in the human body, as well as two-thirds of the average person’s iron intake in developed countries. Hence, a wide range of epidemiological studies have focused on examining the association of dietary heme intake, mainly from red meat, with the risks of common diseases. High heme intake is associated with increased risk of several cancers, including colorectal cancer, pancreatic cancer and lung cancer. Likewise, the evidence for increased risks of type-2 diabetes and coronary heart disease associated with high heme intake is compelling. Furthermore, recent comparative metabolic and molecular studies of lung cancer cells showed that cancer cells require increased intracellular heme biosynthesis and uptake to meet the increased demand for oxygen-utilizing hemoproteins. Increased levels of hemoproteins in turn lead to intensified oxygen consumption and cellular energy generation, thereby fueling cancer cell progression. Together, both epidemiological and molecular studies support the idea that heme positively impacts cancer progression. However, it is also worth noting that heme deficiency can cause serious diseases in humans, such as anemia, porphyrias, and Alzheimer’s disease. This review attempts to summarize the latest literature in understanding the role of dietary heme intake and heme function in diverse diseases.

A prospective investigation of fish, meat and cooking-related carcinogens with endometrial cancer incidence

Background:

There are limited prospective studies of fish and meat intakes with risk of endometrial cancer and findings are inconsistent.

Methods:

We studied associations between fish and meat intakes and endometrial cancer incidence in the large, prospective National Institutes of Health-AARP Diet and Health Study. Intakes of meat mutagens 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and benzo(a)pyrene (BaP) were also calculated. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

We observed no associations with endometrial cancer risk comparing the highest to lowest intake quintiles of red (HR=0.91, 95% CI 0.77–1.08), white (0.98, 0.83–1.17), processed meats (1.02, 0.86–1.21) and fish (1.10, 95% CI 0.93–1.29). We also found no associations between meat mutagen intakes and endometrial cancer.

Conclusion:

Our findings do not support an association between meat or fish intakes or meat mutagens and endometrial cancer.