Fish consumption and breast cancer risk. The European Prospective Investigation into Cancer and Nutrition (EPIC)

Understanding the Role of Polyunsaturated Fatty Acids in the Development and Prevention of Cancer

Polyunsaturated fatty acids (PUFAs), notably omega-3 (n-3) and omega-6 (n-6), have received much attention owing to their multifaceted effects not only in the management of diverse pathological conditions but also in the maintenance of overall health of an individual. A disproportionately high n-6 to n-3 ratio contributes to the development of various disorders including cancer, which ranks as a leading cause of death worldwide with profound social and economic burden. Epidemiological studies and clinical trials combined with the animal and cell culture models have demonstrated the beneficial effects of n-3 PUFAs in reducing the risk of various cancer types including breast, prostate and colon cancer. The anti-cancer actions of n-3 PUFAs are mainly attributed to their role in the modulation of a wide array of cellular processes including membrane dynamics, apoptosis, inflammation, angiogenesis, oxidative stress, gene expression and signal transduction pathways. On the contrary, n-6 PUFAs have been shown to exert pro-tumor actions; however, the inconsistent findings and controversial data emphasize upon the need to further investigation. Nevertheless, one of the biggest challenges in future is to optimize the n-6 to n-3 ratio despite the genetic predisposition, age, gender and disease severity. Moreover, a better understanding of the potential risks and benefits as well as the cellular and molecular mechanisms of the basic actions of these PUFAs is required to explore their role as adjuvants in cancer therapy. All these aspects will be reviewed in this chapter.

Relationship between oily fish intake and breast cancer based on estrogen receptor status: a Mendelian randomization study

OBJECTIVE

We used a Mendelian randomization (MR) method in our research to examine the relationship between genetically determined oily fish intake and breast cancer (BC) incidence.

METHODS

The summary data pertaining to the oily fish intake were acquired from the UK Biobank, which consisted of a sample size of 460,443 people. Information on BC was received from the Breast Cancer Association Consortium (BCAC). We analyzed the causal connection between oily fish intake and BC incidence using various methods, including inverse variance weighting (IVW). Heterogeneity was investigated using Cochran's Q test. IVW, MR-Egger, and MR-PRESSO methods were used for sensitivity analysis. In addition, a multivariate MR adjusted for body mass index (BMI) and weight was used for further research.

RESULTS

Two-sample MR results showed that oily fish intake was negatively associated with total breast cancer (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.39-0.87, IVW method), estrogen receptor-positive (ER +) breast cancer (OR 0.44, 95% CI 0.21-0.93, IVW method), and estrogen receptor-negative (ER-) breast cancer (OR 0.53, 95% CI 0.30-0.93, IVW method). The sensitivity analysis did not observe the presence of heterogeneity and horizontal pleiotropy. In multivariate MR analysis, the negative association between oily fish intake and total breast cancer (P = 0.03) and ER- breast cancer (P = 0.04) risk persisted after adjusting for BMI and body weight. However, no correlation was found in ER + breast cancer (P = 0.30).

CONCLUSION

The oily fish intake has a negatively correlated with the incidence of total breast cancer, particularly in the cases of ER- breast cancer. There is a lack of substantial evidence supporting a link between the oily fish intake and the incidence of ER + breast cancer.

The Risk of Breast Cancer between Western and Mediterranean Dietary Patterns

Breast cancer is a significant public health problem globally and prevention strategies have become of great interest as its incidence rises. Exploring the connection between dietary patterns and the reduction of breast cancer risk is considered a promising approach. High levels of fiber, phytochemicals, a good antioxidant profile, and a composition of advantageous fatty acids are characteristics of healthy dietary programs such as the Mediterranean diet. This review summarized and discussed the active compounds that are considered important in preventing breast cancer, including dietary components from recent related reports. These include polyunsaturated fatty acids, fiber, phytochemicals, and alcohol. Although the exact mechanism for preventing breast cancer using these dietary factors is not well understood, the combination of all the elements in a healthy diet plays a role in reducing breast cancer risk. Considering the elevated probability of breast cancer relapse and mortality, it is crucial to investigate the correlation between a nutritious dietary pattern and breast cancer, while identifying bioactive components that have the potential to mitigate the risk of breast cancer incidence.

Assessing the Highest Level of Evidence from Randomized Controlled Trials in Omega-3 Research

Over the years, there has been heightened interest in the health benefits of n-3 polyunsaturated fatty acids (PUFA) in reducing chronic diseases such as, cardiovascular disease (CVD), cancer, type 2 diabetes, and acute macular degeneration (AMD). Due to inconsistent findings in the evidence, a review to critically examine the plethora of evidence from randomized controlled trials (RCTs) in n-3 PUFA research was undertaken. The aim of this review is to study the highest level of evidence and to identify gaps in n-3 PUFA research. RCTs were originally designed for pharmaceutical research and later adopted for nutrition and food-related research. RCTs with active diseases assume that n-3 PUFA will have "drug" like effects, and this high expectation may have led to the inconsistent evidence in the literature. The inconsistency in the literature may be related to varying doses of n-3 PUFA, sources of n-3 PUFA (food vs. supplement; plant vs. marine), type of n-3 PUFA (mixture vs. purified), trial duration, population characteristics, sample size, and genetic variation. For future research, there is a need to distinguish between primary and secondary prevention, and to focus RCTs on primary prevention of chronic diseases by n-3 PUFA which is lacking in the literature.

Breast cancer and dietary fat quality indices in Iranian women: A case-control study

Background

The association between breast cancer (BC) and different indices of dietary fats has not been well-studied. Thus, this study aimed to investigate the association between BC and dietary fat quality (DFQ) indices in Iranian women.

Methods

This case-control study was conducted on 120 women with breast cancer and 240 healthy women in Tehran, Iran. Food Frequency Questionnaire and nutritionist IV software were used to assess the intake of dietary fats and to calculate the DFQ indices.

Results

The patients with BC had a higher total fat (TF) (P < 0.01) and a lower ratio of polyunsaturated fatty acids (PUFAs) omega-3 to PUFAs omega-6 (ω-3/ω-6) compared with the controls (P < 0.001). TF had a significant association with BC risk (OR: 1.16; 95% CI: 1.01-1.33, P < 0.001). No significant association was found between BC and PUFA/saturated fatty acid ratio or the ω-3/ω-6 ratio.

Conclusion

The patients with BC had a lower ω-3/ω-6 ratio and a higher total dietary fat intake than the healthy women. Total dietary fat intake was also directly associated with the risk of BC. Thus, low-fat diets may have beneficial effects for BC prevention. Further longitudinal studies are warranted.

Association of Fruit, Vegetable, and Animal Food Intakes with Breast Cancer Risk Overall and by Molecular Subtype among Vietnamese Women

BACKGROUND

Evidence on associations between dietary intake and risk of breast cancer subtypes is limited and inconsistent. We evaluated associations of fruit, vegetable, meat, and fish consumption with risk of breast cancer overall and by molecular subtype in the Vietnamese Breast Cancer Study (VBCS).

METHOD

VBCS includes 476 incident breast cancer cases and 454 age-matched controls. Dietary habits over the past 5 years were assessed by in-person interviews using a validated food frequency questionnaire. Associations of food groups with breast cancer were evaluated via logistic regression for overall and molecular subtype with adjustment for age, education, income, family history of cancer, menopausal status, body mass index, exercise, total energy intake, and other potential dietary confounders. Odds ratio (OR) was used to approximate relative risk.

RESULTS

High fruit intake was inversely associated with breast cancer risk, with adjusted ORs [95% confidence intervals (CI)] of 0.67 (95% CI, 0.47-0.95) and 0.41 (95% CI, 0.27-0.61) for second and third tertiles versus first tertile, respectively (Ptrend < 0.001). This association was stronger for triple-negative than other subtypes (Pheterogeneity < 0.001). High intake of freshwater fish was inversely associated with overall breast cancer (ORT3vsT1 = 0.63; 95% CI, 0.42-0.95; Ptrend = 0.03). An inverse association was observed between HER2-enriched subtype and red and organ meat intake (ORT3vsT1 = 0.40; 95% CI, 0.17-0.93; Ptrend = 0.04; Pheterogeneity = 0.50).

CONCLUSIONS

High intakes of fruit and freshwater fish were associated with reduced breast cancer risk; association for the former was stronger for triple-negative subtype.

IMPACT

Our findings suggest high intakes of fruit and freshwater fish may reduce breast cancer risk among Vietnamese women.

Consumption of Food Components of the Mediterranean Diet Decreases the Risk of Breast Cancer in the Makkah Region, Saudi Arabia: A Case-Control Study

Background

Breast cancer is one of the leading causes of death worldwide, it affects both men and women. In Saudi Arabia, breast cancer has been the most prevalent type of cancer in women, for the past few years. Dietary habits and cultural beliefs vary according to region, and further studies are required to demonstrate the relationship between these dietary habits and cultural beliefs and the risk of developing breast cancer. This study is aimed to discover the relationship between preventive dietary factors of the Mediterranean diet and rates of breast cancer among postmenopausal women in the Makkah region of Saudi Arabia.

Methods

A case-control study was conducted in King Abdulla Medical City Hospital, Makkah, Saudi Arabia and included 432 Saudi female participants: 218 in the control group and 214 breast cancer patients. All participants were postmenopausal, around the same age, and all were ethnically Arab Saudis. Data were obtained using a self-administered validated questionnaire.

Results

Study results showed that a diet that includes 1-2 servings of legumes weekly, 1-5 servings of fish weekly, 1-5 servings of dairy products daily, 3-5 servings of fruits and vegetables daily, and more than one cup of black tea and coffee per day significantly (p < 0.05) reduces the risk of breast cancer.

Conclusion

This study demonstrates that consuming a Mediterranean diet, which includes legumes, fish, fruits and vegetables, black tea, coffee, and low intake of dairy products, works as a preventive factor against breast cancer in postmenopausal females from the Makkah region.

Evidence Update on the Relationship between Diet and the Most Common Cancers from the European Prospective Investigation into Cancer and Nutrition (EPIC) Study: A Systematic Review

The European Prospective Investigation into Cancer and Nutrition (EPIC) is a multicentre prospective study conducted in 23 centres in 10 European countries. Here we review the findings from EPIC on the relationship between diet-related exposures and incidence or mortality from the four most frequent cancers in the European population: colorectal, breast, lung, and prostate cancer. We conducted a systematic review following PRISMA guidelines and identified 110 high-quality studies based on the EPIC cohort. Fruit and vegetable consumption had a protective effect against colorectal, breast, and lung cancer, whereas only fruit had a protective effect against prostate cancer. A higher consumption of fish and lower consumption of red and processed meat were related with a lower risk of colorectal cancer; and higher consumption of fatty fish with lower risk of breast cancer. Calcium and yogurt intake were found to protect against colorectal and prostate cancer. Alcohol consumption increased the risk for colorectal and breast cancer. Finally, adherence to the Mediterranean diet emerged as a protective factor for colorectal and breast cancer. The EPIC study results are in agreement with the latest evidence from leading authorities on cancer prevention and help to inform public prevention policies and strategies.

Understanding the function of the tumor microenvironment, and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer (BC), including metastasis, and drug resistance, is driven by multiple signaling pathways in the tumor microenvironment (TME), which hamper antitumor immunity. Recently, long non-coding RNAs have been reported to mediate pathophysiological develop-ments such as metastasis as well as immune suppression within the TME. Given the complex biology of BC, novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes. In this review, we describe the advances in the biology of breast neoplasia, including cellular and molecular biology, heterogeneity, and TME. We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC. Finally, we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms, crustaceans, and fishes and their synergistic effects in combination with other anticancer drugs. Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development, thus assisting current therapeutic regimens.

Dietary Constituents: Relationship with Breast Cancer Prognostic (MCC-SPAIN Follow-Up)

The aim of this study was to characterize the relationship between the intake of the major nutrients and prognosis in breast cancer. A cohort based on 1350 women with invasive (stage I-IV) breast cancer (BC) was followed up. Information about their dietary habits before diagnosis was collected using a semi-quantitative Food Frequency Questionnaire. Participants without FFQ or with implausible energy intake were excluded. The total amount consumed of each nutrient (Kcal/day) was divided into tertiles, considering as “high intakes” those above third tertile. The main effect studied was overall survival. Cox regression was used to assess the association between death and nutrient intake. During a median follow-up of 6.5 years, 171 deaths were observed. None of the nutrients analysed was associated with mortality in the whole sample. However, in normal-weight women (BMI 18.5–25 kg/m²) a high intake of carbohydrates (≥809 Kcal/day), specifically monosaccharides (≥468 Kcal/day), worsened prognostic compared to lowest (≤352 Kcal/day). Hazard Ratios (HRs) for increasing tertiles of intake were HR:2.22 95% CI (1.04 to 4.72) and HR:2.59 95% CI (1.04 to 6.48), respectively (p trend = 0.04)). Conversely, high intakes of polyunsaturated fats (≥135 Kcal/day) improved global survival (HR: 0.39 95% CI (0.15 to 1.02) p-trend = 0.05) compared to the lowest (≤92.8 kcal/day). In addition, a protective effect was found substituting 100 kcal of carbohydrates with 100 kcal of fats in normal-weight women (HR: 0.76 95% CI (0.59 to 0.98)). Likewise, in premenopausal women a high intake of fats (≥811 Kcal/day) showed a protective effect (HR:0.20 95% CI (0.04 to 0.98) p trend = 0.06). Finally, in Estrogen Receptors (ER) negative tumors, we found a protective effect of high intake of animal proteins (≥238 Kcal/day, HR: 0.24 95% CI (0.06 to 0.98). According to our results, menopausal status, BMI and ER status could play a role in the relationship between diet and BC survival and must be taken into account when studying the influence of different nutrients.

Intake of Various Food Groups and Risk of Breast Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Despite increasing evidence for the association of food-based dietary patterns with breast cancer risk, knowledge about the shape of the relationship and the quality of meta-evidence are insufficient. We aimed to summarize the associations between food groups and risks of breast cancer. We performed a systematic literature search of the PubMed and Embase databases up to March 2020. We included cohort, case-cohort, nested case-control studies, and follow-up studies of randomized controlled trials that investigated the relationship between breast cancer risk and at least 1 of the following food groups: red meat, processed meat, fish, poultry, egg, vegetables, fruit, dairy product (overall, milk, yogurt, and cheese), grains/cereals, nuts, legumes, soy, and sugar-sweetened beverages. Summary risk ratios (RRs) and 95% CIs were estimated using a random-effects model for linear and nonlinear relationships. Inverse linear associations were observed for vegetables (RR per 100 g/d, 0.97; 95% CI, 0.95-0.99), fruit (RR per 100 g/d, 0.97; 95% CI, 0.95-0.99), cheese (RR per 30 g/d, 0.95; 95% CI, 0.91-1.00), and soy (RR per 30 g/d, 0.96; 95% CI, 0.94-0.99), while positive associations were observed for red (RR per 100 g/d, 1.10; 95% CI, 1.03-1.18) and processed meat (RR per 50 g/d, 1.18; 95% CI, 1.04-1.33). None of the other food groups were significantly associated with breast cancer risk. A nonlinear association was observed only for milk, such that the intake of >450 g/d increased the risk, while no association was observed for lower intake amounts. High intakes of vegetables, fruit, cheese, and soy products and low intakes of red and processed meat were associated with lower risks of breast cancer. However, causality cannot be inferred from these statistical correlations.

Omega-3, omega-6 and total dietary polyunsaturated fat on cancer incidence: systematic review and meta-analysis of randomised trials

BACKGROUND

The relationship between long-chain omega-3 (LCn3), alpha-linolenic acid (ALA), omega-6 and total polyunsaturated fatty acid (PUFA) intakes and cancer risk is unclear.

METHODS

We searched Medline, Embase, CENTRAL and trials registries for RCTs comparing higher with lower LCn3, ALA, omega-6 and/or total PUFA, that assessed cancers over ≥12 months. Random-effects meta-analyses, sensitivity analyses, subgrouping, risk of bias and GRADE were used.

RESULTS

We included 47 RCTs (108,194 participants). Increasing LCn3 has little or no effect on cancer diagnosis (RR1.02, 95% CI 0.98-1.07), cancer death (RR0.97, 95% CI 0.90-1.06) or breast cancer diagnosis (RR1.03, 95% CI 0.89-1.20); increasing ALA has little or no effect on cancer death (all high/moderate-quality evidence). Increasing LCn3 (NNTH 334, RR1.10, 95% CI 0.97-1.24) and ALA (NNTH 334, RR1.30, 95% CI 0.72-2.32) may slightly increase prostate cancer risk; increasing total PUFA may slightly increase risk of cancer diagnosis (NNTH 125, RR1.19, 95% CI 0.99-1.42) and cancer death (NNTH 500, RR1.10, 95% CI 0.48-2.49) but total PUFA doses were very high in some trials.

CONCLUSIONS

The most extensive systematic review to assess the effects of increasing PUFAs on cancer risk found increasing total PUFA may very slightly increase cancer risk, offset by small protective effects on cardiovascular diseases.

Association of Dietary Intake Ratio of n-3/n-6 Polyunsaturated Fatty Acids with Breast Cancer Risk in Western and Asian Countries: A Meta-Analysis

Objective:

This systematic review and meta-analysis were performed to determine association of dietary intake ratio of n-3/n-6 polyunsaturated fatty acids with breast cancer risk in Western and Asian countries.

Methods:

The authors conducted a meta-analysis of published research articles on association of dietary intake ratio of n-3/n-6 polyunsaturated fatty acids (PUFAs) with breast cancer risk in Western and Asian countries published between January 2000 and February 2019 in online article databases of PubMed, ProQuest and EBSCO. Pooled risk ratios (RR) were calculated using fixed and random-effect models. Publication bias was visually evaluated by performing funnel plots and statistically assessed by Egger’s and Begg’s tests. Data were processed by using Stata version 14.2 (Stata Corporation).

Results:

This study reviewed 913 articles. There were 13 studies included in systematic review continued by meta-analysis of relevant data with total number of samples: 275,264 patients. The results showed dietary intake ratio of n-3/n-6 PUFAs with breast cancer risk in Western and Asian countries (RR = 0.99; 95%CI: 0.92-1.07). Dietary intake ratio of n-3/n-6 PUFAs with breast cancer risk in Western countries reached (RR = 0.98; 95%CI: 0.91-1.06) and there was any significant publication bias for studies included. Dietary intake ratio of n-3/n-6 PUFAs with breast cancer risk in Asian countries reached (RR = 1.18; 95%CI: 0.94-1.47) and there was not any significant publication bias for studies included.

Conclusion:

This analysis confirmed association of dietary intake ratio of n-3/n-6 PUFAs with breast cancer risk in Western and Asian countries. Higher dietary intake ratio is associated with lower risk of breast cancer in Asian countries rather than Western countries. This study suggests increasing dietary intake ratio n-3/n-6 PUFAs will provide benefit for breast cancer prevention.

Protective Effect of Omega-3 Fatty Acids in Fish Consumption Against Breast Cancer in Asian Patients: A Meta-Analysis

Objective:

This systematic review and meta-analysis was performed to determine the protective effect of omega-3 fatty acids in fish consumption against breast cancer in Asian patients.

Methods:

The authors conducted a meta-analysis of published research articles on protective effect of omega-3 fatty acids in fish consumption against breast cancer in Asian patients published between January 2000 and July 2018 in online database of PubMed, ProQuest and EBSCO. Pooled odds ratios (OR) were calculated by using fixed and random-effect models. Publication bias was visually evaluated by using funnel plots and statistically assessed in Egger’s and Begg’s tests. Data were processed by Review Manager 5.3 (RevMan 5.3) and Stata version 14.2 (Stata Corporation).

Results:

This study reviewed 913 articles. There were 11 studies which conducted systematic review then continued by meta-analysis of relevant data with total number of samples were 130,365 patients. The results showed there was protective effect of omega-3 fatty acids in fish consumption against breast cancer in Asian patients (OR = 0.80 [95% CI 0.73-0.87, p <0.00001]). There was not any study with significant publication bias included.

Conclusion:

This analysis confirmed the protective effect of omega-3 fatty acids in fish consumption against breast cancer in Asian patients.

Mediterranean Diet and Prevention of Chronic Diseases

A large body of research data suggests that traditional dietary habits and lifestyle unique to the Mediterranean region (Mediterranean diet, MD) lower the incidence of chronic diseases and improve longevity. These data contrast with troubling statistics in the United States and other high income countries pointing to an increase in the incidence of chronic diseases and the projected explosion in cost of medical care associated with an aging population. In 2013, the MD was inscribed by UNESCO in the "Representative List of the Intangible Cultural Heritage of Humanity." The 2015-2020 Dietary Guidelines for Americans included the MD as a healthy dietary pattern. Therefore, specific objectives of this article are to provide an overview of the nutritional basis of this healthful diet, its metabolic benefits, and its role in multiple aspects of disease prevention and healthy aging. Whereas recommendations about the MD often focus on specific foods or bioactive compounds, we suggest that the eating pattern as a whole likely contributes to the health promoting effects of the MD.

Phytotherapy and Nutritional Supplements on Breast Cancer

Breast cancer is the most frequent type of nonskin malignancy among women worldwide. In general, conventional cancer treatment options (i.e., surgery, radiotherapy, chemotherapy, biological therapy, and hormone therapy) are not completely effective. Recurrence and other pathologic situations are still an issue in breast cancer patients due to side effects, toxicity of drugs in normal cells, and aggressive behaviour of the tumours. From this point of view, breast cancer therapy and adjuvant methods represent a promising and challenging field for researchers. In the last few years, the use of some types of complementary medicines by women with a history of breast cancer has significantly increased such as phytotherapeutic products and nutritional supplements. Despite this, the use of such approaches in oncologic processes may be problematic and patient's health risks can arise such as interference with the efficacy of standard cancer treatment. The present review gives an overview of the most usual phytotherapeutic products and nutritional supplements with application in breast cancer patients as adjuvant approach. Regardless of the contradictory results of scientific evidence, we demonstrated the need to perform additional investigation, mainly well-designed clinical trials in order to establish correlations and allow for further validated outcomes concerning the efficacy, safety, and clinical evidence-based recommendation of these products.

Early Life Residence, Fish Consumption, and Risk of Breast Cancer

Background: Little is known about fish intake throughout the life course and the risk of breast cancer.Methods: We used data on the first residence of 9,340 women born 1908 to 1935 in the Reykjavik Study as well as food frequency data for different periods of life from a subgroup of the cohort entering the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (n = 2,882).Results: During a mean follow-up of 27.3 years, 744 women were diagnosed with breast cancer in the Reykjavik Study. An inverse association of breast cancer was observed among women who lived through the puberty period in coastal villages, compared with women residing in the capital area [HR, 0.78; 95% confidence interval (CI), 0.61-0.99]. In the subgroup analysis of this Icelandic population, generally characterized by high fish intake, we found an indication of lower risk of breast cancer among women with high fish consumption (more than 4 portions per week) in adolescence (HR, 0.71; 95% CI, 0.44-1.13) and midlife (HR, 0.46; 95% CI, 0.22-0.97), compared with low consumers (2 portions per week or less). No association was found for fish liver oil consumption in any time period, which could be due to lack of a reference group with low omega-3 fatty acids intake in the study group.Conclusions: Our findings suggest that very high fish consumption in early to midlife may be associated with a reduced risk of breast cancer.Impact: Very high fish consumption in early adulthood to midlife may be associated with decreased risk of breast cancer. Cancer Epidemiol Biomarkers Prev; 26(3); 346-54. ©2016 AACR.

Dietary Protein Sources and Incidence of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies

Protein is important to the human body, and different sources of protein may have different effects on the risk of breast cancer. Thus, we conducted a meta-analysis to investigate the association between different dietary protein sources and breast cancer risk. PubMed and several databases were searched until December 2015. Relevant articles were retrieved according to specific searching criteria. Forty-six prospective studies were included. The summary relative risk (RR) for highest versus lowest intake was 1.07 (95% confidence interval (CI) 1.01-1.14, I² = 34.6%) for processed meat, 0.92 (95% CI 0.84-1.00, I² = 0%) for soy food, 0.93 (95% CI 0.85-1.00, I² = 40.1%) for skim milk, and 0.90 (95% CI 0.82-1.00, I² = 0%) for yogurt. Similar conclusions were obtained in dose-response association for each serving increase: total red meat (RR: 1.07; 95% CI 1.01-1.14, I² = 7.1%), fresh red meat (RR: 1.13; 95% CI 1.01-1.26, I² = 56.4%), processed meat (RR: 1.09; 95% CI 1.02-1.17, I² = 11.8%), soy food (RR: 0.91; 95% CI 0.84-1.00, I² = 0%), and skim milk (RR: 0.96; 95% CI 0.92-1.00, I² = 11.9%). There was a null association between poultry, fish, egg, nuts, total milk, and whole milk intake and breast cancer risk. Higher total red meat, fresh red meat, and processed meat intake may be risk factors for breast cancer, whereas higher soy food and skim milk intake may reduce the risk of breast cancer.

Mediterranean Diet and cancer risk: an open issue

The traditional Mediterranean Diet of the early 1960s meets the characteristics of an anticancer diet defined by the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AIRC). A diet rich of whole grains, pulses, vegetables and fruits, limited in high-calorie foods (foods high in sugar or fat), red meat and foods high in salt, without sugary drinks and processed meat is recommended by the WCRF/AIRC experts to reduce the risk of cancer. The aim of this review was to examine whether Mediterranean Diet is protective or not against cancer risk. Three meta-analyses of cohort studies reported that a high adherence to the Mediterranean Diet significantly reduces the risk of cancer incidence and/or mortality. Nevertheless, the Mediterranean dietary pattern defined in the studies' part of the meta-analyses has qualitative and/or quantitative differences compared to the Mediterranean Diet of the early 1960s. Therefore, the protective role of the Mediterranean Diet against cancer has not definitely been established. In epidemiological studies, a universal definition of the Mediterranean Diet, possibly the traditional Mediterranean Diet of the early 1960s, could be useful to understand the role of this dietary pattern in cancer prevention.

Combination of Antiestrogens and Omega-3 Fatty Acids for Breast Cancer Prevention

The molecular and biological heterogeneity of human breast cancer emphasizes the importance of a multitargeted approach for effective chemoprevention. Targeting the estrogen receptor pathway alone with the antiestrogens, Tamoxifen and Raloxifene reduces the incidence of estrogen receptor positive tumors but is ineffective against the development of hormone independent cancers. Our preclinical data indicate that the administration of omega-3 fatty acids potentiates the antitumor effects of Tamoxifen by inhibiting multiple proliferative and antiapoptotic pathways, several of which interact with estrogen receptor signaling. The complementarity in the mechanism of antitumor action of Tamoxifen and omega-3 fatty acids is well supported by our signaling, genomic, and proteomic studies. Furthermore, administration of omega-3 fatty acids allows the use of lower and, hence, likely less toxic doses of Tamoxifen. If these findings are supported in the clinical setting, the combination of omega-3 fatty acids and anteistrogens may emerge as a promising, effective, and safe chemopreventive strategy to be tested in a large multi-institutional trial using breast cancer incidence as the primary endpoint.

Fish, n - 3 polyunsaturated fatty acids and n - 6 polyunsaturated fatty acids intake and breast cancer risk: The Japan Public Health Center-based prospective study

Limited and inconsistent studies exist on the association between the intake of fish, n - 3 polyunsaturated fatty acids (PUFA) and n - 6 PUFA and breast cancer. Fish and n - 3 PUFA support various body functions and are thought to reduce the carcinogenesis risk while n - 6 PUFA may have a positive association with cancer risk. We examined the association between intake of fish, n - 3 PUFA [including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and alpha-linolenic acid (ALA)] and n - 6 PUFA and breast cancer with subanalyses on estrogen (ER) and progesterone receptor (PR) status. We investigated 38,234 Japanese women aged 45-74 years from the Japan Public Health Center-based prospective study (JPHC study), and during 14.1 years of follow-up time, 556 breast cancer cases were newly diagnosed. Breast cancer risk was not associated with the intake of total fish, n - 3 PUFA and n - 6 PUFA when analyzed in totality through multivariable Cox proportional hazards regression models with age as the time scale. Intake of total n - 6 was positively associated with the development of ER+PR+ tumors [multivariable-adjusted HR Q4 vs. Q1  = 2.94 (95% CI: 1.26-6.89; ptrend  = 0.02)]. Intake of EPA was associated with a decreased breast cancer risk for ER+PR+ tumors [multivariable-adjusted HR Q2 vs. Q1  = 0.47 (95% CI: 0.25-0.89; ptrend =0.47)]. While the overall association between the intake of total fish, n - 3 PUFA and n - 6 PUFA and breast cancer risk is null, for ER+PR+ tumors, a positive association was seen between n - 6 intake and breast cancer, and a marginally significant inverse association was observed for EPA intake.

Intake of freshwater fish and associated fatty acids and risk of breast cancer

To investigate the association between intake of freshwater fish and their fatty acids and the risk of breast cancer in Chinese women, we conducted a case-control study with 669 cases and 682 population-based controls in Jiangsu Province of China. A structured questionnaire was used to elicit detailed information. Unconditional logistic regression analysis was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Total freshwater fish intake was linked to decrease in the adjusted OR for breast cancer, but without dose-dependence. Analyses by freshwater fish species showed that consumption of black carp and silver carp was inversely related to breast cancer risk, with adjusted-ORs for the highest intake category of black carp (≥500g/month) of 0.54 (95%CI=0.33-0.92; P trend<0.002) and for silver carp (≥1000g/month) of 0.19 (95%CI=0.11-0.33; P trend<0.001). In contrast, consumption of crucian carp was positively related to breast cancer risk, with an adjusted OR for the highest intake category (≥1000g/month) of 6.09 (95%CI=3.04-12.2; P trend<0.001). Moderate intakes of SFA, PUFA, n3-PUFA and n6-PUFA from freshwater fish may decrease the risk of breast cancer among premenopausal women. The findings of this study suggest that intake of freshwater fish and their fatty acids may modify risk of breast cancer, and that different species of freshwater fish could have a different actions on breast cancer risk. Future epidemiologic studies are needed to know the effects of freshwater fish intake on breast cancer risk and the cause of these effects.

Vitamin D in cancer chemoprevention

CONTEXT

There is increasing evidence that Vitamin D (Vit D) and its metabolites, besides their well-known calcium-related functions, may also exert antiproliferative, pro-differentiating, and immune modulatory effects on tumor cells in vitro and may also delay tumor growth in vivo.

OBJECTIVE

The aim of this review is to provide fresh insight into the most recent advances on the role of Vit D and its analogues as chemopreventive drugs in cancer therapy.

METHODS

A systematic review of experimental and clinical studies on Vit D and cancer was undertaken by using the major electronic health database including ISI Web of Science, Medline, PubMed, Scopus and Google Scholar.

RESULTS AND CONCLUSION

Experimental and clinical observations suggest that Vit D and its analogues may be effective in preventing the malignant transformation and/or the progression of various types of human tumors including breast cancer, prostate cancer, colorectal cancer, and some hematological malignances. These findings suggest the possibility of the clinical use of these molecules as novel potential chemopreventive and anticancer agents.

Fish consumption and mortality in the European Prospective Investigation into Cancer and Nutrition cohort

Fish is a source of important nutrients and may play a role in preventing heart diseases and other health outcomes. However, studies of overall mortality and cause-specific mortality related to fish consumption are inconclusive. We examined the rate of overall mortality, as well as mortality from ischaemic heart disease and cancer in relation to the intake of total fish, lean fish, and fatty fish in a large prospective cohort including ten European countries. More than 500,000 men and women completed a dietary questionnaire in 1992-1999 and were followed up for mortality until the end of 2010. 32,587 persons were reported dead since enrolment. Hazard ratios and their 99% confidence interval were estimated using Cox proportional hazard regression models. Fish consumption was examined using quintiles based on reported consumption, using moderate fish consumption (third quintile) as reference, and as continuous variables, using increments of 10 g/day. All analyses were adjusted for possible confounders. No association was seen for fish consumption and overall or cause-specific mortality for both the categorical and the continuous analyses, but there seemed to be a U-shaped trend (p < 0.000) with fatty fish consumption and total mortality and with total fish consumption and cancer mortality (p = 0.046).

Dietery factor obesity microenvironnement and breast cancer

BACKGROUND

Breast cancer is a multifactorial disease. Factors most often mentioned risks are those related to the environment, genetics, hormones and individual behaviors. Among these include alcohol, smoking, sedentary lifestyle and eating habits. Identification of eating and the role of nutritional factors may be involved in cancer risk have been studied extensively since nearly 40 years.

PURPOSE

We conducted a study of breast cancer type case-control with food frequency questionnaire to assess the causal relationship between dietary factor, obesity and breast cancer risk.

PATIENTS AND METHODS

female patients with breast cancer were compared to healthy controls at the National Institute of Oncology of Rabat during 2008-2010 and were interviewed for epidemiological information and for their eating habits.

RESULTS

A total of 800 women were included in this study (400 cases and 400 controls). Result of univariate analysis showed that significant factors associated with the etiologie of breast cancer: high body mass index (BMI) [odds ratio (OR) =1.30; 95% confidence interval (CI), 1.25-1.37], red meat (OR =1.33; 95% CI, 1.27-1.40), processed meat (OR =1.44; 95% CI, 1.35-1.54), eggs (OR =1.20; 95% CI, 1.14-1.23), poultry (OR =0.70; 95% CI, 0.60-0.80), fish (OR =0.67; 95% CI, 0.61-0.73), fruit (OR =0.67; 95% CI, 0.62-0.72), and vegetable (OR=0.72; 95% CI, 0.67-0.78). Multivariate analysis indicated that a significantly elevated risk of contracting breast cancer was associated with higher BMI (OR =9.61; 95% CI, 6.1-15.15), red meat (OR =4.61; 95% CI, 2.26-9.44) and processed meat (OR =9.78; 95% CI, 4.73-20.24). In contrast consumption of fish (OR =0.07; 95% CI, 0.02-0.24), poultry (OR =0.61; 95% CI, 0.46-0.81), fruit (OR =0.001; 95% CI, 0.00-0.004), and vegetable (OR =0.82; 95% CI, 0.22-3.08) remained as significant beneficial factor associated with breast cancer.

CONCLUSIONS

This study is rather in favour of positive association between obesity, consumption of food rich in fatty matter and breast cancer, which is consistent with data from the literature using the same type of investigation. These results encourage increased cohort studies, case-control and experimentation in order to achieve a genuine code of cancer prevention, to define with precision the positive and negative.

Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study

OBJECTIVE

To investigate the association between dietary protein sources in early adulthood and risk of breast cancer.

DESIGN

Prospective cohort study.

SETTING

Health professionals in the United States.

PARTICIPANTS

88,803 premenopausal women from the Nurses' Health Study II who completed a questionnaire on diet in 1991.

MAIN OUTCOME MEASURE

Incident cases of invasive breast carcinoma, identified through self report and confirmed by pathology report.

RESULTS

We documented 2830 cases of breast cancer during 20 years of follow-up. Higher intake of total red meat was associated with an increased risk of breast cancer overall (relative risk 1.22, 95% confidence interval 1.06 to 1.40; P(trend) = 0.01, for highest fifth v lowest fifth of intake). However, higher intakes of poultry, fish, eggs, legumes, and nuts were not related to breast cancer overall. When the association was evaluated by menopausal status, higher intake of poultry was associated with a lower risk of breast cancer in postmenopausal women (0.73, 0.58 to 0.91; P(trend) =0.02, for highest fifth v lowest fifth of intake) but not in premenopausal women (0.93, 0.78 to 1.11; P(trend) = 0.60, for highest fifth v lowest fifth of intake). In estimating the effects of exchanging different protein sources, substituting one serving/day of legumes for one serving/day of red meat was associated with a 15% lower risk of breast cancer among all women (0.85, 0.73 to 0.98) and a 19% lower risk among premenopausal women (0.81, 0.66 to 0.99). Also, substituting one serving/day of poultry for one serving/day of red meat was associated with a 17% lower risk of breast cancer overall (0.83, 0.72 to 0.96) and a 24% lower risk of postmenopausal breast cancer (0.76, 0.59 to 0.99). Furthermore, substituting one serving/day of combined legumes, nuts, poultry, and fish for one serving/day of red meat was associated with a 14% lower risk of breast cancer overall (0.86, 0.78 to 0.94) and premenopausal breast cancer (0.86, 0.76 to 0.98).

CONCLUSION

Higher red meat intake in early adulthood may be a risk factor for breast cancer, and replacing red meat with a combination of legumes, poultry, nuts and fish may reduce the risk of breast cancer.

Influence of omega-3 fatty acids on Tamoxifen-induced suppression of rat mammary carcinogenesis

We report here a detailed time course study of the individual and combined chemopreventive effects of Tamoxifen (Tam) and a high fish oil (FO) diet on multiple histologic parameters of mammary carcinogenesis. Groups of female Sprague-Dawley rats were injected ip with 1-methyl-1-nitrosourea at 50 days of age and assigned to either a control diet (20% corn oil [CO]) or a FO-rich diet (10% FO + 10% CO) in the presence and absence of Tam in the diet (0.6 ppm). Rats were sacrificed at weeks 4 (before palpable tumors), 8 and 12 (when ∼90% of control rats had palpable tumors). Our results demonstrate a major effect of Tam in inhibiting the development of early preneoplastic lesions. FO, while having a marginal protective effect of it own, enhanced the antitumor action of Tam on all histologic parameters of carcinogenesis, although the effects of the combination were not statistically different from those of Tam alone. The combination of FO and Tam was the only intervention that induced regression of established preneoplastic lesions. We also found that in contrast to plasma, only target tissue n-3 fatty acids (FAs) levels correlated with select tissue biomarkers of carcinogenesis whose expression was altered in a manner predictive of a protective effect. Our results demonstrating the potentially superior chemopreventive efficacy of Tam and n-3FA have important translational implications. Our data also emphasize the importance of local factors in affecting target tissue levels and biologic effects of n-3FA.

mTORC1/2 targeted by n-3 polyunsaturated fatty acids in the prevention of mammary tumorigenesis and tumor progression

Although epidemiological and preclinical studies have shown the preventative effects of n-3 polyunsaturated fatty acids (PUFAs) on breast cancer, inconsistencies still remain in the data and the underlying mechanisms remain unclear. In this study, we identified mammalian target of rapamycin (mTOR) signaling, which plays an essential role in cell proliferation and breast tumorigenesis, as a target of n-3 PUFAs. In breast cancer cell lines, n-3 PUFAs rapidly and efficiently suppress both mTOR complex 1 (mTORC1) and mTORC2 and their downstream signaling, and subsequently inhibit cell proliferation and angiogenesis while promoting apoptosis. Further study indicates that stabilization of the mTOR-raptor complex by n-3 PUFAs may contribute to their inhibitory effect on mTORC1. Importantly, four complementary and well-controlled animal models were utilized to identify the role and molecular target of n-3 PUFAs in the prevention of breast carcinogenesis and progression, namely: (1) chemically induced mammary tumor rats with a high dietary intake of n-3 PUFAs; (2) nude mice implanted with mammary tumor cell lines stably expressing fat-1, a desaturase that catalyzes the conversion of n-6 to n-3 PUFAs and produces n-3 PUFAs endogenously; (3) fat-1 transgenic severe combined immune deficiency mice implanted with breast tumor cells; and (4) the fat-1 transgenic mouse mammary tumor virus-polyoma virus middle T oncogene double-hybrid mice, a model of aggressive breast cancer. In summary, dietary and endogenous n-3 PUFAs abrogate the activity of mTORC1/2 pathways in vitro and in vivo and prevent breast carcinogenesis, tumor growth and metastasis. Taken together, our findings convincingly clarify the causal relationship between n-3 PUFAs and breast cancer prevention and establish mTORC1/2 as a target of n-3 PUFAs.

n-3 polyunsaturated fatty acids and HER2-positive breast cancer: interest of the fat-1 transgenic mouse model over conventional dietary supplementation

Overexpression of the tyrosine kinase receptor ErbB2/HER2/Neu, occurs in 25%-30% of invasive breast cancer (BC) with poor patient prognosis. Even if numerous studies have shown prevention of breast cancer by n-3 fatty acid intake, the experimental conditions under which n-3 fatty acids exert their protective effect have been variable from study to study, preventing unifying conclusions. Due to confounding factors, inconsistencies still remain regarding protective effects of n-3 polyunsaturated fatty acids (PUFA) on BC. When animals are fed with dietary supplementation in n-3 fatty acids (the traditional approach to modify tissue content and decrease the n-6/n-3 ratio) complex dietary interactions can occur among dietary lipids (antioxidants, vitamins…) that can modulate the activity of n-3 fatty acids. So, what are the specific roles of these n-3 PUFA in reducing breast cancer risk and particularly preventing HER2-positive breast cancer? In this review, we discuss crucial points that may account for discrepancies of results and provide a highly effective genetic approach that can eliminate confounding factors of diet for evaluating the molecular mechanisms of n-3 PUFA in HER2 signaling pathway regulation. The fat-1 transgenic mouse model is capable of converting n-6 to n-3 fatty acids leading to an increase in n-3 fatty acid content with a balanced n-6/n-3 fatty acid ratio in all tissues. The fat-1 mouse model allows well-controlled studies in HER2-positive breast cancer prevention to be performed, without the conflict of potential confounding factors of diet.

Health benefits of seafood; is it just the fatty acids?

There is a considerable body of literature suggesting a wide range of health benefits associated with diets high in seafood. However, the demand for seafood across the world now exceeds that available from capture fisheries. This has created a rapidly increasing market for aquaculture products, the nutrient composition of which is dependent on feed composition. The use of fishmeal in this food chain does little to counteract the environmental impact of fisheries and so the on-going development of alternative sources is to be welcomed. Nevertheless, an in-depth understanding as to which nutrients in seafood provide benefit is required to permit the production of foods of maximal health benefit to humans. This paper reviews our current knowledge of the beneficial nutrient composition of seafood, in particular omega-3 fatty acids, selenium, taurine, vitamins D and B12, in the context of the development of environmentally sustainable aquaculture.

Telomere length and LINE1 methylation is associated with chromosomal aberrations in peripheral blood

The frequency of chromosomal aberrations in peripheral blood predicts a probable cancer risk. The individual telomere length and methylation of repetitive elements may be susceptibility factors for chromosomal aberrations. A cohort of healthy Norwegian men (N = 364) recruited during 1980-1999 were analyzed for chromosomal aberrations in phytohemagglutinin-stimulated lymphocytes from peripheral blood. Chromosome-type or chromatid-type aberrations were scored. DNA was extracted from slides cytogenetically analyzed and relative average telomere length and methylation of LINE1 repeats were determined by quantitative polymerase chain reaction and bisulfite pyrosequencing, respectively. Information about individuals with malignant tumors (N = 49) diagnosed after chromosomal aberrations testing until end of 2008 was obtained and two matched controls per case were used in a nested case-control analysis. Shorter relative telomere length and higher methylation of LINE1 were associated with higher frequency of total chromosomal aberrations (β = -0.76, P = 0.022; and β = 0.042, P = 0.048, respectively; age-adjusted ordinal regression). The telomere length was stronger associated with chromosome-type (β = -1.00, P = 0.006) than with chromatid-type aberrations (β = -0.49, P = 0.115). The LINE1 methylation was stronger associated with chromatid-type (β = 0.062, P = 0.003) than with chromosome-type aberrations (β = 0.018, P = 0.41). Telomere length [individuals with short telomeres odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.38-2.0], LINE1 (individuals with high methylation OR = 1.04, 95% CI 0.43-2.5) and chromosomal aberrations (individuals with high frequency OR = 1.6, 95% CI 0.63-3.9) at baseline did not predict cancer risk, but the conclusions were hampered by low statistical precision. The results suggest that shorter telomere length and higher LINE1 methylation in peripheral blood lymphocytes are predisposition factors for increased frequency of chromosomal aberrations.

Fruit, vegetable, and animal food intake and breast cancer risk by hormone receptor status

The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by the hormone receptor status of tumors among Chinese women. The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996-1998 (phase I) and 2002-2005 (phase II); 2676 cases had estrogen receptor (ER) and progesterone receptor (PR) data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models. Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67-0.95; P trend = 0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend < 0.05), whereas intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the 4 tumor subtypes or between ER+/PR+ and ER-/PR- tumors (P for heterogeneity >0.05). Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, whereas high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.

Proteomic approaches to predict bioavailability of fatty acids and their influence on cancer and chronic disease prevention

A low intake of fish and PUFA and high dietary trans- and SFA are considered to be among the main preventable causes of death. Unfortunately, epidemiological and preclinical studies have yet to identify biomarkers that accurately predict the influence of fatty acid intake on risk of chronic diseases, including cancer. Changes in protein profile and post-translational modifications in tissue and biofluids may offer important clues about the impact of fatty acids on the etiology of chronic diseases. However, conventional protein methodologies are not adequate for assessing the impact of fatty acids on protein expression patterns and modifications and the discovery of protein biomarkers that predict changes in disease risk and progression in response to fatty acid intake. Although fluctuations in protein structure and abundance and inter-individual variability often mask subtle effects caused by dietary intervention, modern proteomic platforms offer tremendous opportunities to increase the sensitivity of protein analysis in tissues and biofluids (plasma, urine) and elucidate the effects of fatty acids on regulation of protein networks. Unfortunately, the number of studies that adopted proteomic tools to investigate the impact of fatty acids on disease risk and progression is quite small. The future success of proteomics in the discovery of biomarkers of fatty acid nutrition requires improved accessibility and standardization of proteomic methodologies, validation of quantitative and qualitative protein changes (e.g., expression levels, post-translational modifications) induced by fatty acids, and application of bioinformatic tools that can inform about the cause-effect relationships between fatty acid intake and health response.

Dietary sources of omega 3 fatty acids: public health risks and benefits

Omega 3 fatty acids can be obtained from several sources, and should be added to the daily diet to enjoy a good health and to prevent many diseases. Worldwide, general population use omega-3 fatty acid supplements and enriched foods to get and maintain adequate amounts of these fatty acids. The aim of this paper was to review main scientific evidence regarding the public health risks and benefits of the dietary sources of omega-3 fatty acids. A systematic literature search was performed, and one hundred and forty-five articles were included in the results for their methodological quality. The literature described benefits and risks of algal, fish oil, plant, enriched dairy products, animal-derived food, krill oil, and seal oil omega-3 fatty acids.

Benefits and risks of fish consumption for the human health

The article aimed at identifying and discussing scientific evidences on the benefits and risks of fish consumption the human health. There was a systematic survey for articles published from 2003 and May 2011, at the MedLine, Scopus, SciELO, Lilacs and Google Scholar databases. The key words used were: fish, food intake, omega-3 fatty acids, fatty fish, benefits, risk, and consumption. The search produced 12,632 articles, 25 eligible cohort studies on possible benefits, 61 on risks and 10 studies that assessed the "risk/benefit" relation. Of the 25 works, 14 suggested a preventive effect of fish consumption related to cardiovascular diseases, depression, cataract and some types of cancer. Evidences of a relation between exposure to mercury and an increase in the risk of neurological disorders, but not of cardiovascular diseases, were also found. Given the importance of fish consumption, its possible risks and the lack of Brazilian studies on the topic, it is important to conduct more longitudinal studies that assess both the benefits and risks of fish consumption for the human health. We also emphasize the need for policies to reduce exposure of fish and seafood to mercury and other contaminants.

The mediterranean dietary pattern and breast cancer risk in Greek-Cypriot women: a case-control study

BACKGROUND

Diet has long been suspected to impact on breast cancer risk. In this study we evaluated whether the degree of adherence to a Mediterranean diet pattern modifies breast cancer risk amongst Greek-Cypriot women.

METHODS

Subjects included 935 cases and 817 controls, all participating in the MASTOS case-control study in Cyprus. The study was approved by the Cyprus National Bioethics Committee. Information on dietary intakes was collected using an interviewer administered 32-item Food Frequency Questionnaire. Information on demographic, anthropometric, lifestyle, and other confounding factors was also collected. Adherence to the Mediterranean Diet pattern was assessed using two a-priory defined diet scores. In addition, dietary patterns specific to our population were derived using Principal Component Analysis (PCA). Logistic regression models were used to assess the association between the dietary patters and breast cancer risk.

RESULTS

There was no association with breast cancer risk for either score, however, higher consumptions of vegetables, fish and olive oil, were independently associated with decreased risk. In addition, the PCA derived component which included vegetables, fruit, fish and legumes was shown to significantly reduce risk of breast cancer (ORs across quartiles of increasing levels of consumption: 0.89 95%CI: 0.65-1.22, 0.64 95%CI: 0.47-0.88, 0.67 95%CI: 0.49-0.92, P trend < 0.0001), even after adjustment for relevant confounders.

CONCLUSIONS

Our results suggest that adherence to a diet pattern rich in vegetables, fish, legumes and olive oil may favorably influence the risk of breast cancer. This study is the first investigation of dietary effects on breast cancer risk in Cyprus, a country whose population has traditionally adhered to the Mediterranean diet.

Update on the relationship of fish intake with prostate, breast, and colorectal cancers

A systematic review of prospective cohort and case-control studies investigating relationships between the intake of fish and incidence of prostate, breast, or colorectal cancers was conducted. A total of 106 studies fulfilled the requirements stated in the "Search strategy and selection criteria." Among 273 estimates of association reported by these studies, 53 indicated decreased risk while 12 indicated increased risk associated with fish intake. The hypothesis linking fish consumption and low cancer incidence appears to be supported by little epidemiological data. However, there are several factors that may mask potential protective associations with fish intake. The type and the amount of fish eaten, the cooking method, the stage of the cancer and, amongst women, menopausal status may all be important factors that relate to whether fish is protective or not. Future epidemiologic studies with a clearer assessment of these factors are needed to know more about the effects of fish consumption on cancer risk. Therefore, until there are better measures of dietary exposure or biomarkers to correlate self-report, no conclusion can be drawn regarding the recommendation for increasing fish consumption in general to reduce the risk of developing the most common cancers in Western societies.

ω-3 and ω-6 Polyunsaturated fatty acid intakes and the risk of breast cancer in Mexican women: impact of obesity status

BACKGROUND

ω-3 polyunsaturated fatty acids (PUFA) could play a protective role on the risk of breast cancer; however, little is known about this relation among Mexican women. We evaluated the association between ω-3 and ω-6 PUFA intake and breast cancer risk by obesity status in Mexican women.

METHODS

A population-based case-control study was conducted in Mexico, including 1,000 incident breast cancer cases and 1,074 controls matched to cases by age, health care system, and region. Women provided information on health and diet by in-person interview. Body mass index (BMI) measures were used to define overall obesity. Obesity status was categorized as normal weight (18.5 < BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). A conditional logistic regression model was used to assess the association between PUFA and breast cancer risk.

RESULTS

Overall, there was no significant association between ω-3 PUFA intake and breast cancer risk (P = 0.31). An increased risk of breast cancer was associated with increasing ω-6 PUFA intake in premenopausal women [OR = 1.92, 95% confidence interval (CI) = 1.13-3.26; P = 0.04]. A decreased risk of breast cancer was significantly associated with increasing ω-3 PUFA intake in obese women (OR = 0.58, 95% CI = 0.39-0.87; P = 0.008) but not in normal weight nor in overweight women (P(heterogeneity) = 0.017).

CONCLUSIONS

Obesity status may affect the association between ω-3 PUFA intake and breast cancer risk. The underlying mechanisms may be related to decreased inflammation and improved adipokin and estrogen levels induced by ω-3 PUFA in adipose tissue in obese women.

IMPACT

Increased intake of ω-3 PUFA should be recommended among Mexican women in particular in obese women.

Chemoprevention of breast cancer by fish oil in preclinical models: trials and tribulations

Despite the perception that omega-3 fatty acids (n-3 FA) protect against breast cancer, epidemiologic studies have yielded inconsistent results. Although preclinical data have been, in general, more supportive of a protective effect of n-3 FA on breast cancer, inconsistencies still remain, which preclude definite conclusions or in-depth mechanistic investigations despite 30 years of research in this area. In this review, we discuss key variables that may account for inconsistencies of results across preclinical studies and provide recommendations for future experiments testing the chemopreventive effect of n-3 FAs in breast cancer, as part of a multiagent approach under rigorously controlled conditions.

Mammary gland density predicts the cancer inhibitory activity of the N-3 to N-6 ratio of dietary fat

This study investigated the effect of a broad range of dietary ratios of n-3:n-6 fatty acids on mammary gland density and mammary cancer risk. Cancer was induced in female rats by N-methyl-N-nitrosourea. Purified diet that provided 30% of dietary kilocalories from fat was formulated to contain ratios of n-3:n-6 fatty acids from 25:1 to 1:25. Mammary gland density was determined by digital analysis, fatty acids by gas chromatography/flame ionization detection, and other plasma analytes via ELISA. Mammary gland density was reduced dose dependently at n-3:n-6 ratios from 1:1 to 25:1 (r = -0.477, P = 0.038), with a 20.3% decrease of mammary gland density between n-3:n-6 of 1:1 versus 25:1, P < 0.001. Mammary carcinogenesis was inhibited in the absence or presence of tamoxifen (1 mg/kg diet) in a manner predicted by mammary gland density. Plasma n-3 fatty acid concentrations failed to increase above an n-3:n-6 ratio of 5:1, and changes in specific plasma n-3 or n-6 fatty acids were not predictive of mammary gland density or cancer inhibitory activity. A strong reciprocal effect of the n-3:n-6 ratio on plasma leptin (decreased, P = 0.005) and adiponectin (increased, P < 0.001) was observed indicating adipose tissue function was modulated. However, neither cytokine was predictive of mammary gland density. Plasma insulin-like growth factor I (IGF-I) decreased with increasing dietary n-3:n-6 ratio (P = 0.004) and was predictive of the changes in mammary gland density (r = 0.362, P < 0.005). These findings indicate that (i) mammary gland density predicted the carcinogenic response, (ii) the n-3:n-6 ratio exerts effects in the presence or absence of hormonal regulation of carcinogenesis, and (iii) signaling pathways regulated by IGF-I are potential targets for further mechanistic investigation.

Dietary conjugated linoleic acid and long-chain n-3 fatty acids in mammary and prostate cancer protection: a review

The role of dietary fatty acids on cancer is still controversial. To examine the current literature on the protective role of conjugated linoleic acid (CLA) and marine long-chain fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] and the risk of breast and prostate cancer, data from 41 case-control and cohort studies and relevant in vitro and animal experiments were included in this 2000-2010 revision. Epidemiological studies on CLA intake or its tissue concentration related to breast and prostate tumorigenesis are not conclusive; EPA and DHA intake have shown important inverse associations just in some studies. Additional research on the analysed association is required.

Meat and egg consumption and risk of breast cancer among Chinese women

OBJECTIVE

The association between meat and egg consumption and breast cancer risk has been examined in previous studies, but the results were inconsistent. We conducted a hospital-based case-control study during June 2007 to August 2008 among Guangdong Chinese women to investigate associations between meat and egg intake and breast cancer risk.

METHODS

Four hundred and thirty-eight consecutively recruited cases with primary breast cancer were frequency matched to 438 controls by age (5-year interval) and residence (rural/urban). Dietary intake was assessed by face-to-face interviews using a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were obtained by using multiple unconditional logistic regression adjusted for various dietary and nondietary confounders.

RESULTS

We observed a borderline increased association of processed meat intake with breast cancer risk (trend test p = 0.066). The multivariate-adjusted OR of breast cancer risk for the highest versus the lowest quartile was 1.44 (95% CI = 0.97–2.15). No significant association was found between total and red meat, poultry, fish, and egg intake and risk.

CONCLUSIONS

This study suggested that processed meat intake was associated with a possible increased risk of breast cancer. There was no significant association between consumption of total and red meat, poultry, fish, or egg with breast cancer risk.

Cancer and noncancer mortality among American seafood workers

Background

Few studies have investigated mortality in seafood workers worldwide, and no such study has been conducted in the United States. The objective of this study was to investigate mortality in American seafood workers.

Methods

The study population was derived from 4 states and consisted of 4116 subjects who worked mainly in seafood processing plants. They were followed up from 1966 to 2003. Standardized mortality ratios (SMRs) and proportional mortality ratios (PMRs) were estimated, using the US general population for comparison.

Results

About 45% of the cohort was born after 1949. A total of 788 deaths were recorded; 53% of the decedents were female, and 88% were white. The SMRs for stomach cancer and disorders of the thyroid gland in the cohort as a whole were 2.1 (95% confidence interval [CI], 1.1–3.8) and 6.1 (95% CI 1.3–18.0), respectively. The SMRs for breast cancer, and occlusion/stenosis of the pre-cerebral/cerebral arteries in the cohort as a whole were 0.5 (95% CI, 0.3–0.9) and 0.5 (95% CI, 0.2–0.8), respectively. The SMR for ischemic heart disease in white females was 0.8 (95% CI, 0.6–0.9).

Conclusions

This cohort had excess deaths from stomach cancer and disorders of the thyroid gland, and deficit of deaths from breast cancer, stroke and ischemic heart disease. The significance of these findings is unknown, especially as less than 20% of the cohort were deceased. Nevertheless, the cohort is unique and important, and further follow-up may shed more light on mortality patterns in this occupational group.

Preventing diet induced disease: bioavailable nutrient-rich, low-energy-dense diets

What the World needs is an integrated and sustainable food policy that makes the best and most appropriate use of the technologies at our disposal to promote health and help prevent disease. Diet induced diseases account for the largest burden of chronic illnesses and health problems Worldwide. Historically a lack of knowledge about human nutritional requirements (including for the brain) helped promote diet induced disease. The scientific knowledge currently exists to help prevent many of the current deficiencies and imbalances in human diet. Primary prevention of cardiovascular disease and mental ill health starts, crucially, with maternal nutrition before the inception of pregnancy and continues throughout life of the new born and includes consuming more DHA and EPA omega-3 fats (and their cofactors) and other bioavailable brain nutrients and less high-energy-dense (>2 kcal g(-1)) foods (e.g. land-based cereal, chocolate, alcohol and refined sugar, fat and oil), so tissues synthesize less inflammatory mediators and to lower transient short-lived meal-induced oxidative stress, inflammation, proliferation and impaired nitric oxide (e.g. approximately 0.35-3.5 g DHA/ EPA day(-1) dependant on energy intake and noting the importance of cofactors). Micro- and nanotechnologies are already engineering nano foods for human (and livestock) consumption that may eventually (without excessive consumption) prevent the current diet induced disease epidemic, especially in future generations, by preventing the causal mechanisms of disease. Greater knowledge about the causal mechanisms of disease awaits to be discovered, which could further enhance the human desire to increase longevity in optimum health (creating more problems and challenges for society).

Fatty fish and fish omega-3 fatty acid intakes decrease the breast cancer risk: a case-control study

Background

Although it is believed that fish ω-3 fatty acids may decrease breast cancer risk, epidemiological evidence has been inconclusive. This study examined the association between fish and fish ω-3 fatty acids intake with the risk of breast cancer in a case-control study of Korean women.

Methods

We recruited 358 incident breast cancer patients and 360 controls with no history of malignant neoplasm from the National Cancer Center Hospital between July 2007 and April 2008. The study participants were given a 103-item food intake frequency questionnaire to determine their dietary consumption of fish (fatty and lean fish) and ω-3 fatty acids derived from fish (eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)).

Results

Using a multivariate logistic regression model, high intake of fatty fish was associated with a reduced risk for breast cancer in both pre- and postmenopausal women (OR [95% CI] for highest vs. lowest intake quartiles, p for trend: 0.19 [0.08 to 0.45], p < 0.001 for premenopausal women, 0.27 [0.11 to 0.66], p = 0.005 for postmenopausal women). Similarly, reductions in breast cancer risk were observed among postmenopausal subjects who consumed more than 0.101 g of EPA (OR [95% CI]: 0.38 [0.15 to 0.96]) and 0.213 g of DHA (OR [95% CI]: 0.32 [0.13 to 0.82]) from fish per day compared to the reference group who consumed less than 0.014 g of EPA and 0.037 g of DHA per day. Among premenopausal women, there was a significant reduction in breast cancer risk for the highest intake quartiles of ω-3 fatty acids (ORs [95% CI]: 0.46 [0.22 to 0.96]), compared to the reference group who consumed the lowest quartile of intake.

Conclusion

These results suggest that high consumption of fatty fish is associated with a reduced risk for breast cancer, and that the intake of ω-3 fatty acids from fish is inversely associated with postmenopausal breast cancer risk.

Towards establishing dietary reference intakes for eicosapentaenoic and docosahexaenoic acids

There is considerable interest in the impact of (n-3) long-chain PUFA in mitigating the morbidity and mortality caused by chronic diseases. In 2002, the Institute of Medicine concluded that insufficient data were available to define Dietary Reference Intakes (DRI) for eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), noting only that EPA and DHA could contribute up to 10% toward meeting the Adequate Intake for alpha-linolenic acid. Since then, substantial new evidence has emerged supporting the need to reassess this recommendation. Therefore, the Technical Committee on Dietary Lipids of the International Life Sciences Institute North America sponsored a workshop on 4-5 June 2008 to consider whether the body of evidence specific to the major chronic diseases in the United States--coronary heart disease (CHD), cancer, and cognitive decline--had evolved sufficiently to justify reconsideration of DRI for EPA+DHA. The workshop participants arrived at these conclusions: 1) consistent evidence from multiple research paradigms demonstrates a clear, inverse relation between EPA+DHA intake and risk of fatal (and possibly nonfatal) CHD, providing evidence that supports a nutritionally achievable DRI for EPA+DHA between 250 and 500 mg/d; 2) because of the demonstrated low conversion from dietary ALA, protective tissue levels of EPA+DHA can be achieved only through direct consumption of these fatty acids; 3) evidence of beneficial effects of EPA+DHA on cognitive decline are emerging but are not yet sufficient to support an intake level different from that needed to achieve CHD risk reduction; 4) EPA+DHA do not appear to reduce risk for cancer; and 5) there is no evidence that intakes of EPA+DHA in these recommended ranges are harmful.

Dietary patterns and risk of cancer of various sites in the Norwegian European Prospective Investigation into Cancer and Nutrition cohort: the Norwegian Women and Cancer study

An indicator of common diets among groups of individuals can be found by identifying dietary patterns. We found previously six dietary patterns in the Norwegian European Prospective Investigation into Cancer and Nutrition cohort and labelled them fish, healthy, average, western, bread and alcohol. We examined the relationship between the different patterns and risk of total cancer, breast cancer and gastrointestinal cancers in 34 471 women from the Norwegian European Prospective Investigation into Cancer and Nutrition cohort, in which there were 1355 cancer cases. The hazard ratios and their corresponding 95% confidence intervals were estimated using Cox proportional hazards regression. Stratified analysis on menopausal status and smoking status was performed. Alcohol, meat, fish and fruit and vegetable consumption are suspected to have an influence on different cancers; thus we decided to perform stratified analysis on high versus low consumption of the above-mentioned variables as well. We found no overall relationship between cancers and the six different dietary patterns in this study. When stratifying on alcohol consumption, fruit and vegetable consumption and fatty fish consumption, there was a statistically higher risk of total cancer and breast cancer with high alcohol consumption, and a significantly higher risk of breast cancer with low consumption of fruit and vegetables or with low consumption of fatty fish in the western group only. A significantly higher risk of total cancer with low intake of fatty fish in the alcohol group was also observed.