N-3 and N-6 fatty acids in breast adipose tissue and relative risk of breast cancer in a case-control study in Tours, France

Alpha linolenic acid and oleic acid additively down-regulate malignant potential and positively cross-regulate AMPK/S6 axis in OE19 and OE33 esophageal cancer cells

OBJECTIVE

Both oleic acid (OA) and alpha-linolenic acid (ALA) have been proposed to down-regulate cell proliferation of prostate, breast, and bladder cancer cells. However, direct evidence that OA and/or ALA suppresses to the development of esophageal cancer has not been studied. Also, no previous studies have evaluated how OA and/or ALA regulates malignant potential (cell proliferation, migration, colony formation and adhesion) and intracellular signaling pathways, and whether their effects might be synergistic and/or additive in esophageal cancer cells has not yet been elucidated.

MATERIALS/METHODS

We conducted in vitro studies and evaluated whether OA and ALA alone or in combination may regulate malignant potential in OE19 and OE33 esophageal cancer cell lines.

RESULTS

Both OA and ALA significantly down-regulated cell proliferation, adhesion and/or migration. OA and/or ALA did not change the number of colonies but decrease colony sizes when compared to control. Also, we observed that OA and/or ALA positively cross-regulates the expression levels of AMPK/S6 axis. Moreover, OA and ALA up-regulated tumor suppressor genes (p53, p21, and p27) and these effects are abolished by AMPK siRNA administration. Importantly, we observed that these effects are additively regulated by OA and ALA in combination when compared to control in OE19 and OE33 esophageal cancer cell lines.

CONCLUSIONS

Our novel mechanistic studies provide evidence for an important role for OA and ALA in esophageal cancer, and suggest that OA and/or ALA might be useful agents in the management or chemoprevention of esophageal cancer.

n-3 polyunsaturated fatty acids and mechanisms to mitigate inflammatory paracrine signaling in obesity-associated breast cancer

Globally, the prevalence of obesity is increasing which subsequently increases the risk of the development of obesity-related chronic diseases. Low-grade chronic inflammation and dysregulated adipose tissue inflammatory mediator/adipokine secretion are well-established in obesity, and these factors increase the risk of developing inflammation-associated cancer. Breast cancer is of particular interest given that increased inflammation within the subcutaneous mammary adipose tissue depot can alter the local tissue inflammatory microenvironment such that it resembles that of obese visceral adipose tissue. Therefore, in obese women with breast cancer, increased inflammatory mediators both locally and systemically can perpetuate inflammation-associated pro-carcinogenic signaling pathways, thereby increasing disease severity. Herein, we discuss some of these inflammation-associated pro-carcinogenic mechanisms of the combined obese breast cancer phenotype and offer evidence that dietary long chain n-3 polyunsaturated fatty acids (PUFA) may have utility in mitigating the severity of obesity-associated inflammation and breast cancer.

Analysis of high fat diet induced genes during mammary gland development: identifying role players in poor prognosis of breast cancer

BACKGROUND

Epidemiological studies have shown that consumption of a high-fat diet (HFD) increases the risk of developing breast cancer (BC). Studies in rodents have shown HFD causes changes in the genetic programming of the maturing mammary gland (MG) increasing the susceptibility of developing the disease. Less is known about how HFD induced genes impact BC development. HFD exposure two weeks before conception to six weeks of age was previously shown to dramatically change MG gene expression in 10 week old mice. Therefore, we investigated these differentially expressed HFD-induced genes for their expression in BC using the NKI 295 breast tumor dataset.

RESULTS

To examine the potential role of HFD induced genes in BC, we first investigated whether these HFD-induced genes in mouse MGs were differentially expressed in different types of human BC. Of the 28 HFD induced genes that were differentially expressed between BC subtypes in the NKI set, 79% were significantly higher in basal-like BC. Next, we analyzed whether HFD induced genes were associated with BC prognosis utilizing gene expression and survival data for each HFD induced gene from the NKI data and constructed Kaplan Meier survival plots. Significantly, 93% of the prognosis associated genes (13/14) were associated with poor prognosis (P = 0.002). Kaplan Meier analysis with 249 non-basal-like BC found that all but one of the genes examined were still significantly associated with poor prognosis. Furthermore, gene set enrichment analysis (GSEA) with HFD microarray data revealed that invasive BC genes where enriched in HFD samples that also had lost expression of luminal genes.

CONCLUSIONS

HFD exposed mouse MGs maintain differential expression of genes that are found highly expressed in basal-like breast cancer. These HFD-induced genes associate with poor survival in numerous BC subtypes, making them more likely to directly impact prognosis. Furthermore, HFD exposure leads to a loss in the expression of luminal genes and a gain in expression of mesenchymal and BC invasion genes in MGs. Collectively, our study suggests that HFD exposure during development induces genes associated with poor prognosis, thus identifying how HFD diet may regulate BC development.

Mammary tumour development is dose-dependently inhibited by n-3 polyunsaturated fatty acids in the MMTV-neu(ndl)-YD5 transgenic mouse model

Background

Breast cancer is attributable to modifiable risk factors including the intake of dietary n-3 polyunsaturated fatty acids (PUFA). A key piece of evidence, yet to be addressed, that would demonstrate a causal relationship between n-3 PUFA and breast cancer, is a dose-dependent effect of n-3 PUFA on tumour outcomes. Thus, the objective of the present study was to determine whether n-3 PUFA reduces mammary gland tumor outcomes in a dose-dependent manner in female MMTV-neu(ndl)-YD5 transgenic mice, an aggressive model of human breast cancer.

Methods

Harems were provided one of three experimental diets comprised of 0, 3 or 9% (w/w) menhaden fish oil containing n-3 PUFA. Female offspring were weaned onto the same parental diet and maintained on their respective diet for 20 weeks. Tumour onset, size and multiplicity were measured throughout the study. Fatty acid composition of mammary gland and tumours were determined by gas–liquid chromatography.

Results

Tumour size was significantly (p < 0.05) reduced in a dose-dependent manner. n-3 PUFA were also incorporated in a dose-dependent manner; differential incorporation was observed for eicosapentaenoic and docosapentaenoic acids into mammary gland tissue, while docosahexaenoic acid was preferentially incorporated into tumours.

Conclusion

Overall, the present study provides fundamental knowledge about the dose-dependent effect of n-3 PUFA on tumour outcomes in a pre-clinical model and also sheds light on the differential role of individual n-3 PUFA on tumour outcomes.

Ratio of n-3/n-6 PUFAs and risk of breast cancer: a meta-analysis of 274135 adult females from 11 independent prospective studies

Background

Increased ratio of n-3/n-6 polyunsaturated fatty acids (PUFAs) in diet or serum may have a protective effect on the risk of breast cancer (BC); however, the conclusions from prospective studies are still controversial. The purpose of this study is to ascertain the relationship between intake ratio of n-3/n-6 PUFAs and the risk of BC, and estimate the potential summarized dose–response trend.

Methods

Relevant English-language studies were identified through Cochrane Library, PubMed and EMBASE database till April 2013. Eligible prospective studies reporting the multivariate adjusted risk ratios (RRs) for association of n-3/n-6 PUFAs ratio in diet or serum with BC risk. Data extraction was conducted independently by 2 investigators; disagreements were reconciled by consensus. Study quality was assessed using the Newcastle-Ottawa scale. Study-specific RRs were combined via a random-effects model.

Results

Six prospective nested case–control and 5 cohort studies, involving 8,331 BC events from 274,135 adult females across different countries, were included in present study. Subjects with higher dietary intake ratio of n-3/n-6 PUFAs have a significantly lower risk of BC among study populations (pooled RR = 0.90; 95% CI: 0.82, 0.99), and per 1/10 increment of ratio in diet was associated with a 6% reduction of BC risk (pooled RR = 0.94; 95% CI: 0.90, 0.99; P for linear trend = 0.012). USA subjects with higher ratio of n-3/n-6 in serum phospholipids (PL) have a significantly lower risk of BC (pooled RR = 0.62; 95% CI: 0.39, 0.97; I² = 0.00%; P for metaregression = 0.103; P for a permutation test = 0.100), and per 1/10 increment of ratio in serum PL was associated with 27% reduction of BC risk (pooled RR = 0.73; 95% CI: 0.59, 0.91; P for linear trend = 0.004; P for metaregression = 0.082; P for a permutation test = 0.116).

Conclusions

Higher intake ratio of n-3/n-6 PUFAs is associated with lower risk of BC among females, which implies an important evidence for BC prevention and treatment is by increasing dietary intake ratio of n-3/n-6 PUFA. No firm conclusions from USA populations could be obtained, due to the limited numbers of USA studies.

Maternal dietary canola oil suppresses growth of mammary carcinogenesis in female rat offspring

As suggested by rodent studies and studies using human breast cancer cells, dietary canola oil is linked with lower breast cancer risk. Here, we investigated the effect of maternal (pregnancy plus lactation) dietary canola oil on the susceptibility of female Sprague-Dawley rat offspring to mammary carcinogenesis. Although the control diet had 10% soybean oil, the treatment diet was formulated to contain 10% canola oil as a fat source. N-nitroso-N-methylurea was injected to induce mammary cancer in offspring. The offspring of canola-fed dams showed significantly decreased tumor multiplicity (1.0 ± 0.3 vs. 1.9 ± 0.3, respectively; P = 0.04) and tumor volume (1232.5 ± 771.0 mm(3) vs. 6,302.5 ± 1,747.4 mm(3), respectively; P = 0.01), along with increased survival rate (87% vs. 47%, respectively; P = 0.01). In addition, the mRNA expression of development-related gamma-glutamyltransferase 1 was significantly higher in the lactating mammary tissues of the canola group dams and mammary tumor tissues of the offspring [2.5 ± 0.6 vs. 0.5 ± 0.2, respectively (P = 0.01) and 0.98 ± 0.03 vs. 0.56 ± 0.15, respectively (P = 0.05)]. These results suggest a potential anticancer effect of maternal dietary canola oil and may be useful in devising prenatal nutritional strategies to reduce breast cancer risk in humans.

Unsaturated fatty acids, desaturases, and human health

With the increasing concern for health and nutrition, dietary fat has attracted considerable attention. The composition of fatty acids in a diet is important since they are associated with major diseases, such as cancers, diabetes, and cardiovascular disease. The biosynthesis of unsaturated fatty acids (UFA) requires the expression of dietary fat-associated genes, such as SCD, FADS1, FADS2, and FADS3, which encode a variety of desaturases, to catalyze the addition of a double bond in a fatty acid chain. Recent studies using new molecular techniques and genomics, as well as clinical trials have shown that these genes and UFA are closely related to physiological conditions and chronic diseases; it was found that the existence of alternative transcripts of the desaturase genes and desaturase isoforms might affect human health and lipid metabolism in different ways. In this review, we provide an overview of UFA and desaturases associated with human health and nutrition. Moreover, recent findings of UFA, desaturases, and their associated genes in human systems are discussed. Consequently, this review may help elucidate the complicated physiology of UFA in human health and diseases.

The role of the tissue omega-6/omega-3 fatty acid ratio in regulating tumor angiogenesis

Angiogenesis is a necessary step in tumor growth and metastasis. It is well established that the metabolites of omega-6 and omega-3 fatty acids, which must be obtained through the diet and cannot be synthesized de novo in mammals, have differential effects on cellular processes. Omega-6 fatty acid (n-6 FA)-derived metabolites promote angiogenesis by increasing growth factor expression whereas omega-3 fatty acids (n-3 FA) have anti-angiogenic and antitumor properties. However, most studies thus far have failed to account for the role of the n-6 FA/n-3 FA ratio in angiogenesis and instead examined the absolute levels of n-6 and n-3 FA. This review highlights the biochemical interactions between n-6 and n-3 FA and focuses on how the n-6/n-3 FA ratio in tissues modulates tumor angiogenesis. We suggest that future work should consider the n-6/n-3 FA ratio to be a key element in experimental design and analysis. Furthermore, we recommend that clinical interventions should aim to both reduce n-6 metabolites and simultaneously increase n-3 FA intake.

Adipose tissue fatty acid composition and colon cancer: a case-control study

PURPOSE

An increased dietary intake of fat, particularly polyunsaturated fatty acids (PUFAs), has been related to an increased risk of breast, prostate and colon cancers. Patients with and without colon cancer were tested for differences in their fatty stores composition.

METHODS

The fatty acid levels were determined by gas-liquid chromatography in adipose tissue samples, subcutaneous and visceral, obtained intra-operatively from 52 colon cancer and 50 nonneoplastic abdominal disease patients. Statistical analysis was performed using one-way ANOVA, SNK test and Dunnet test. Differences in the composition of saturated, monounsaturated and polyunsaturated fatty acids, in visceral and in subcutaneous samples of colon cancer and nonneoplastic patients, were assessed.

RESULTS

The sum of saturated and monounsaturated fatty acids, respectively, in visceral and in subcutaneous samples, was higher in neoplastic patients (p < 0.001). The sum of some n-6 polyunsaturated fatty acids (PUFAs), the dietary precursor linoleic acid (LA-18:2n-6), and their metabolites, gammalinolenic acid (GLA-18:3n-6) + dihomogammalinolenic acid (DGLA-20:3n-6) + arachidonic acid (AA-22:4n-6), was higher in subcutaneous fat of controls (p < 0.05). The samples from these patients had a fatty acid composition, both subcutaneous and visceral, with a higher content of alphalinolenic acid (ALA-18:3n-3) and stearidonic acid (SDA-18:4n-3) compared to neoplastic patients (p < 0.001). These had subcutaneous and visceral fat stores statistically higher in GLA, DGLA and AA (p < 0.001). Colon cancer patients had subcutaneous adipose stores higher in ALA and LA than visceral sites (p < 0.001).

CONCLUSIONS

Fatty acids may be involved in colon carcinogenesis and there is a depot-specific impact on this process by visceral fat.

Plants, diet, and health

Chronic disease is a major social challenge of the twenty-first century. In this review, we examine the evidence for discordance between modern diets and those on which humankind evolved as the cause of the increasing incidence of chronic diseases, and the evidence supporting consumption of plant foods as a way to reduce the risk of chronic disease. We also examine the evidence for avoiding certain components of plant-based foods that are enriched in Western diets, and review the mechanisms by which different phytonutrients are thought to reduce the risk of chronic disease. This body of evidence strongly suggests that consuming more fruits and vegetables could contribute both to medical nutrition therapies, as part of a package of treatments for conditions like type 2 diabetes, heart disease, cancer, and obesity, and to the prevention of these diseases. Plant science should be directed toward improving the quality of plant-based foods by building on our improved understanding of the complex relationships between plants, our diet, and our health.

Arachidonic acid and cancer risk: a systematic review of observational studies

Background

An n-6 essential fatty acid, arachidonic acid (ARA) is converted into prostaglandin E₂, which is involved in tumour extension. However, it is unclear whether dietary ARA intake leads to cancer in humans. We thus systematically evaluated available observational studies on the relationship between ARA exposure and the risk of colorectal, skin, breast, prostate, lung, and stomach cancers.

Methods

We searched the PubMed database for articles published up to May 17, 2010. 126 potentially relevant articles from the initial search and 49,670 bibliographies were scrutinised to identify eligible publications by using predefined inclusion criteria. A comprehensive literature search yielded 52 eligible articles, and their reporting quality and methodological quality was assessed. Information on the strength of the association between ARA exposure and cancer risk, the dose-response relationship, and methodological limitations was collected and evaluated with respect to consistency and study design.

Results

For colorectal, skin, breast, and prostate cancer, 17, 3, 18, and 16 studies, respectively, were identified. We could not obtain eligible reports for lung and stomach cancer. Studies used cohort (n = 4), nested case-control (n = 12), case-control (n = 26), and cross-sectional (n = 12) designs. The number of subjects (n = 15 - 88,795), ARA exposure assessment method (dietary intake or biomarker), cancer diagnosis and patient recruitment procedure (histological diagnosis, cancer registries, or self-reported information) varied among studies. The relationship between ARA exposure and colorectal cancer was inconsistent based on ARA exposure assessment methodology (dietary intake or biomarker). Conversely, there was no strong positive association or dose-response relationship for breast or prostate cancer. There were limited numbers of studies on skin cancer to draw any conclusions from the results.

Conclusions

The available epidemiologic evidence is weak because of the limited number of studies and their methodological limitations, but nonetheless, the results suggest that ARA exposure is not associated with increased breast and prostate cancer risk. Further evidence from well-designed observational studies is required to confirm or refute the association between ARA exposure and risk of cancer.

Endogenous n-3 polyunsaturated fatty acids delay progression of pancreatic ductal adenocarcinoma in Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice

Preclinical studies suggest that diets rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs) may be beneficial for prevention of pancreatic cancer. Nutritional intervention studies are often complex, and there is no clear evidence, without potential confounding factors, on whether conversion of n-6 PUFAs to n-3 PUFAs in pancreatic tissues would provide protection. Experiments were designed using n-3 fatty acid desaturase (Fat-1) transgenic mice, which can convert n-6 PUFA to n-3 FAs endogenously, to determine the impact of n-3 PUFAs on pancreatic intraepithelial neoplasms (PanINs) and their progression to pancreatic ductal adenocarcinoma (PDAC). Six-week-old female p48(Cre/+)-LSL-Kras(G12D/+) and compound Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice were fed (AIN-76A) diets containing 10% safflower oil for 35 weeks. Pancreata were evaluated histopathologically for PanINs and PDAC. Results showed a dramatic reduction in incidence of PDAC (84%; P < .02) in Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice compared to p48(Cre/+)-LSL-Kras(G12D/+) mice. Importantly, significant reductions of pancreatic ducts with carcinoma (90%; P < .0001) and PanIN 3 (~50%; P < .001) lesions were observed in the compound transgenic mice. The levels of n-3 PUFA were much higher (>85%; P < .05-0.01) in pancreas of compound transgenic mice than in those of p48(Cre/+)-LSL-Kras(G12D/+) mice. Molecular analysis of the pancreas showed a significant down-regulation of proliferating cell nuclear antigen, cyclooxygenase-2, 5-lipoxygenase (5-LOX), 5-LOX-activating protein, Bcl-2, and cyclin D1 expression levels in Fat-1-p48(Cre/+)-LSL-Kras(G12D/+) mice compared to p48(Cre/+)-LSL-Kras(G12D/+) mice. These data highlight the promise of dietary n-3 FAs for chemoprevention of pancreatic cancer in high-risk individuals.

Comparing an olive oil-enriched diet to a standard lower-fat diet for weight loss in breast cancer survivors: a pilot study

BACKGROUND

Traditional diets that include moderate to high intakes of extra virgin olive oil have been related to a decrease in breast cancer risk. We hypothesized that an olive oil-enriched diet would lead to greater weight loss and acceptance, compared with a standard diet, in women previously diagnosed with invasive breast cancer.

METHODS

Participants consumed a National Cancer Institute (NCI) diet (total fat > 15% and < 30%) and a plant-based olive oil diet (PBOO; > or = 3 tablespoons of olive oil/day) for 8 weeks, each with random assignment to the order. We established a weight loss goal of at least 5% of baseline weight. After completion of the two diet trials, each participant self-selected one of the diets for an additional 6 months of follow-up for weight management. Body measures were done before and after each diet and after follow-up; fasting blood samples were collected after each diet and after follow-up.

RESULTS

Forty-four overweight women started and 28 completed the 44-week protocol. Twelve (80%) of the 15 women who started with the PBOO diet achieved a weight loss of > or = 5% compared to 4 (31%) of the 13 who started with the NCI diet (p < 0.01). Nineteen of the 22 women eligible for follow-up chose the PBOO diet, and all completed the study. Of the 3 women who chose the NCI diet for follow-up, 1 completed the study. The PBOO diet resulted in lower triglycerides (NCI 105 +/- 46 mg/dL, PBOO 96 +/- 37 mg/dL, p = 0.06) and higher high-density lipoprotein cholesterol (HDL-C) (NCI 64 +/- 13 mg/dL, PBOO 68 +/- 12 mg/dL, p = 0.001).

CONCLUSIONS

An olive oil-enriched diet brought about greater weight loss than a lower-fat diet in an 8-week comparison. Moreover, these women chose, overwhelmingly, the olive oil-enriched diet for 6 months of follow-up. An olive oil-enriched diet may be more efficacious for weight loss in breast cancer survivors than a standard lower-fat diet.

Mammary tumor development is directly inhibited by lifelong n-3 polyunsaturated fatty acids

INTRODUCTION

Despite the advocacy that diet may be a significant contributor to cancer prevention, there is a lack of direct evidence from epidemiological and experimental studies to substantiate such claims. Experimental studies suggest that n-3 polyunsaturated fatty acids (n-3 PUFA) from marine oils may reduce breast cancer risk, however, findings are equivocal. Thus, in this study, novel transgenic mouse models were employed to provide, for the first time, direct evidence for an anti-cancer role of n-3 PUFA in mammary tumorigenesis.

METHODS

fat-1 Mice, which are capable of endogenous n-3 PUFA synthesis, were bred with mouse mammary tumor virus (MMTV)-neu(ndl)-YD5 mice, an aggressive breast cancer model. The resultant offspring, including novel hybrid progeny, were assessed for tumor onset, size and multiplicity as well as n-3 PUFA composition in mammary gland and tumor tissue. A complementary group of MMTV-neu(ndl)-YD5 mice were fed n-3 PUFA in the diet.

RESULTS

Mice expressing MMTV-neu(ndl)-YD5 and fat-1 displayed significant (P<.05) reductions in tumor volume (~30%) and multiplicity (~33%), as well as reduced n-6 PUFA and enriched n-3 PUFA in tumor phospholipids relative to MMTV-neu(ndl)-YD5 control mice. The effect observed in hybrid progeny was similarly observed in n-3 PUFA diet fed mice.

CONCLUSION

Using complementary genetic and conventional dietary approaches we provide, for the first time, unequivocal experimental evidence that n-3 PUFA is causally linked to tumor prevention.

High levels of arachidonic acid and peroxisome proliferator-activated receptor-alpha in breast cancer tissues are associated with promoting cancer cell proliferation

Fatty acids are endogenous ligands of peroxisome proliferator-activated receptor-alpha (PPARα), which is linked to the regulation of fatty acid uptake, lipid metabolism and breast cancer cell growth. This study was designed to screen candidate fatty acids from breast cancer tissue and to investigate the effects of these candidate fatty acids on PPARα expression, cell growth and cell cycle progression in breast cancer cell lines. One breast cancer tissue and one reference tissue were each taken from 30 individual breasts to examine for fatty acid composition and PPARα expression. The cancer cell lines MDA-MB-231 (ER-), MCF-7 (ER++++) and BT-474 (ER++) were used to explore the mechanisms regulating cell proliferation. We found that arachidonic acid (AA) and PPARα were highly expressed in the breast cancer tissues. AA stimulated the growth of all three breast cancer cells in a time- and dose-dependent manner. The growth stimulatory effect of AA was associated with PPARα activation, and the most potent effect was found in MCF-7 cells. The stimulation of cell proliferation by AA was accompanied by the increased expression of cyclin E, a reduced population of G1 phase cells, and a faster G1/S phase transition. In contrast, AA had no effects on the levels of CDK2, CDK4, cyclin D1, p27, Bcl-2 and Bax. Our results demonstrate that high levels of AA and PPARα expression in human breast cancer tissues are associated with ER-overexpressed breast cancer cell proliferation, which is involved in activating PPARα, stimulating cyclin E expression, and promoting faster G1/S transition.

The janus face of lipids in human breast cancer: how polyunsaturated Fatty acids affect tumor cell hallmarks

For several years, lipids and especially n - 3 and n - 6 polyunsaturated fatty acids (PUFAs) receive much attention in human health. Epidemiological studies tend to correlate a PUFA-rich diet with a reduced incidence of cancer, including breast cancer. However, the molecular and cellular mechanisms supporting the effect of PUFAs in breast cancer cells remain relatively unknown. Here, we review some recent progress in understanding the impact that PUFA may have on breast cancer cell proliferation, apoptosis, migration, and invasion. While most of the results obtained with docosahexaenoic acid and/or eicosapentaenoic acid show a decrease of tumor cell proliferation and/or aggressivity, there is some evidence that other lipids, which accumulate in breast cancer tissues, such as arachidonic acid may have opposite effects. Finally, lipids and especially PUFAs appear as potential adjuvants to conventional cancer therapy.

Proximate and fatty acid composition of some commercially important fish species from the Sinop region of the Black Sea

The proximate and fatty acid compositions of the commercially important fish species (Engraulis encrasicolus, Alosa alosa, Belone belone, Scorpaena porcus, Pomatomus saltatrix, Mullus barbatus) from the Sinop region of the Black Sea were examined. The fat contents ranged from 1.26% (for scorpion fish) to 18.12% (for shad). The protein contents were min 14.54% (for red mullet) and maximum 20.26% (for belone). The fatty acid compositions of the fish ranged from 27.83 to 35.91% for saturated fatty acids, 19.50-33.80% for monounsaturated fatty acids and 15.25-40.02% for polyunsaturated fatty acids. Among the saturated fatty acids, palmitic acid (16:0) (17.75-22.20%) was the dominant fatty acid for all the fish species. As a second saturated fatty acid, myristic acid (14:0) was observed in four of the fish species and its content ranged from 4.72 to 7.31%. Whereas, for the other two fish species, the second saturated fatty acid was stearic acid (18:0) ranging between 4.54 and 10.64%. Among the monounsaturated fatty acids, those occurring in the highest proportions were oleic acid (18:1n-9c) (11.67-22.45%) and palmitoleic acid (16:1) (4.50-9.40%). Docosahexaenoic acid (22:6n-3) (5.41-28.52%), eicosapentaenoic acid (20:5n-3) (4.68-11.06) and linoleic acid (18:2n-6) (1.38-3.49%) were dominant polyunsaturated fatty acids, respectively. All the species, in particular the belone, the anchovy and the shad had high levels of the n-3 series.

Perfluorinated compounds are related to breast cancer risk in Greenlandic Inuit: a case control study

BACKGROUND

Breast cancer (BC) is the most common cancer for women in the western world. From very few cases an extraordinary increase in BC was observed in the Inuit population of Greenland and Canada although still lower than in western populations. Previous data suggest that exposure to persistent organic pollutants (POPs) might contribute to the risk of BC. Rat studies showed that perfluorinated compounds (PFCs) cause significantly increase in mammary fibroadenomas. This study aimed at evaluating the association between serum levels of POPs/PFCs in Greenlandic Inuit BC cases and their controls, and whether the combined POP related effect on nuclear hormone receptors affect BC risk.

METHODS

Thirty-one BC cases and 115 controls were sampled during 2000-2003 from various Greenlandic districts. The serum levels of POPs, PFCs, some metals and the combined serum POP related effect on estrogen- (ER), androgen- (AR) and Ah-receptor (AhR) transactivity were determined. Independent student t-test was used to compare the differences and the odds ratios were estimated by unconditional logistic regression models.

RESULTS

We observed for the very first time a significant association between serum PFC levels and the risk of BC. The BC cases also showed a significantly higher concentration of polychlorinated biphenyls at the highest quartile. Also for the combined serum POP induced agonistic AR transactivity significant association to BC risk was found, and cases elicited a higher frequency of samples with significant POP related hormone-like agonistic ER transactivity. The AhR toxic equivalent was lowest in cases.

CONCLUSIONS

The level of serum POPs, particularly PFCs, might be risk factors in the development of BC in Inuit. Hormone disruption by the combined serum POP related xenoestrogenic and xenoandrogenic activities may contribute to the risk of developing breast cancer in Inuit. Further investigations are needed to document these study conclusions.

Dietary ratio of n-6 to n-3 polyunsaturated fatty acids and periodontal disease in community-based older Japanese: a 3-year follow-up study

The longitudinal relationship between dietary n-6 to n-3 PUFAs ratio and periodontal disease in 235 Japanese subjects for whom data were available for the years 2003-2006 was investigated. PUFAs intake was assessed at baseline with a brief-type self-administered diet history questionnaire. Full-mouth periodontal status, measured as the clinical attachment level (CAL), was recorded at baseline and once a year for 3 years. The number of teeth with a change in the loss of CAL ≥3 mm at any site over a year was calculated as 'periodontal disease events'. Poisson regression analysis was conducted, with dietary n-6 to n-3 PUFAs ratio as the main predictor, to estimate its influence on periodontal disease events. A high dietary n-6 to n-3 PUFAs ratio was significantly associated with greater number of periodontal disease events. The findings suggest the dietary n-6 to n-3 PUFAs ratio is associated with periodontal disease among older Japanese.

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.

In vivo determination of human breast fat composition by ¹H magnetic resonance spectroscopy at 7 T

The role of diet and fat consumption in the pathogenesis of breast cancer is an important subject. We report a method for noninvasive determination of lipid composition in human breast by proton magnetic resonance spectroscopy (MRS) at 7 T. Two respiratory-triggered TE-averaged stimulated echo acquisition mode (STEAM) acquisitions were performed on the adipose tissue of 10 healthy volunteers where the second acquisition had all gradients inverted. This acquisition protocol allows the suppression of modulation sidebands that complicate spectral analysis at the short TE(avg) = 24.5 ms. The entire acquisition takes ∼10 min. Ten lipid peaks were typically resolved. T(1) and T(2) were also measured and used to correct the peak intensities. The calculated average lipid composition for saturated was 28.7 ± 8.4%, monounsaturated, 48.5 ± 7.9%, and polyunsaturated, 22.7 ± 3.1%, in close agreement with reported values from subcutaneous adipose measurements. Intrasubject variability was 2.0, 1.6, and 3.6% for the saturated, monounsaturated, and polyunsaturated fractions, respectively. In conclusion, we have shown that a chemical analysis of lipids in breast tissue can be determined quite simply, quickly, and noninvasively by proton MRS at 7 T.

The ω-3 epoxide of eicosapentaenoic acid inhibits endothelial cell proliferation by p38 MAP kinase activation and cyclin D1/CDK4 down-regulation

BACKGROUND AND PURPOSE

Dietary intake of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) like eicosapentaenoic acid (EPA) decreases cancer risk, while arachidonic acid and other ω-6 PUFAs increase risk, but the underlying mechanisms are unclear. Cytochrome P450 (CYP)-derived epoxides contribute to enhanced tumourigenesis due to ω-6 PUFA intake. Thus, ω-6 arachidonic acid epoxides (EETs) inhibit apoptosis and stimulate proliferation by up-regulating cyclin D1 expression in cells. The present study evaluated the corresponding ω-3 PUFA epoxides and assessed their role in the regulation of cell proliferation.

EXPERIMENTAL APPROACH

Four chemically stable EPA epoxides (formed at the 8,9-, 11,12-, 14,15- and 17,18-olefinic bonds) were synthesized and tested against growth-related signalling pathways in brain microvascular endothelial bEND.3 cells. Cell cycle distribution was determined by flow cytometry and cyclin gene expression by immunoblotting and real-time PCR. The role of the p38 mitogen-activated protein (MAP) kinase in cyclin D1 dysregulation was assessed using specific inhibitors and dominant-negative expression plasmids.

KEY RESULTS

The ω-3 17,18-epoxide of EPA decreased cell proliferation, interrupted the cell cycle in S-phase and down-regulated the cyclin D1/cyclin-dependent kinase (CDK)-4 complex, whereas the 8,9-, 11,12- and 14,15-epoxides were either inactive or enhanced proliferation. Cyclin D1 down-regulation by 17,18-epoxy-EPA was mediated by activation of the growth-suppressing p38 MAP kinase, but the alternate EPA-epoxides were inactive.

CONCLUSIONS AND IMPLICATIONS

The present findings suggest that the epoxide formed by CYP enzymes at the ω-3 olefinic bond may contribute to the beneficial effects of ω-3 PUFA by down-regulating cyclin D1 and suppressing cell proliferation.

Marine fatty acid intake is associated with breast cancer prognosis

EPA and DHA, long-chain (n-3) PUFA largely obtained from fish, inhibit the proliferation of breast cancer cells in vitro and reduce the initiation and progression of breast tumors in laboratory animals. Our purpose in this analysis was to examine whether intake of these marine fatty acids (EPA and DHA) were associated with prognosis in a cohort of women who had been diagnosed and treated for early stage breast cancer (n = 3,081). Median follow-up was 7.3 y. Dietary intake was assessed using 24-h recalls (~4 recalls per dietary assessment obtained at 7 time points over 6 y). Survival models with time-dependent covariates were used to examine the association of repeated measures of dietary intake of EPA and DHA from food (i.e., marine sources) and supplements with disease-free survival and overall survival. Women with higher intakes of EPA and DHA from food had an approximate 25% reduced risk of additional breast cancer events [tertile 2: HR = 0.74 (95% CI = 0.58-0.94); tertile 3: HR = 0.72 (95% CI = 0.57-0.90)] compared with the lowest tertile of intake. Women with higher intakes of EPA and DHA from food had a dose-dependent reduced risk of all-cause mortality [tertile 2: HR = 0.75 (95% CI = 0.55-1.04); tertile 3: HR = 0.59 (95% CI = 0.43-0.82)]. EPA and DHA intake from fish oil supplements was not associated with breast cancer outcomes. The investigation indicates that marine fatty acids from food are associated with reduced risk of additional breast cancer events and all-cause mortality.

Efficiency of oxidative phosphorylation in liver mitochondria is decreased in a rat model of peritoneal carcinosis

BACKGROUND & AIMS

Cancer cachexia is a dynamic process characterized by a negative energy balance induced by anorexia and hypermetabolism. The mechanisms leading to hypermetabolism are not totally elucidated. This study examines the efficiency of oxidative phosphorylation and energy wasting in liver mitochondria isolated from rats with cancer cachexia induced by peritoneal carcinosis (PC).

METHODS

PC was generated by an intraperitoneal injection of cancer cells (PROb) in BDIX rats. The efficiency of oxidative phosphorylation and energy wasting as well as the role played by reactive oxygen species (ROS) and cardiolipin (mitochondrial inner membrane phospholipid) in these processes were assessed in liver mitochondria of PC and pair-fed control rats.

RESULTS

The efficiency of oxidative phosphorylation decreased (-26%) while energy wasting increased (+22%) in liver mitochondria from PC compared to control rats. The increased energy wasting was associated with a higher cardiolipin content (+55%, p<0.05; R(2)=0.64, p<0.05) and with a lower n-6/n-3 polyunsaturated fatty acid ratio in cardiolipin (-45%, p<0.05; R(2)=0.21, p<0.05) in PC rats. ROS production was increased by 12-fold in liver mitochondria from PC rats.

CONCLUSIONS

The efficiency of ATP synthesis was reduced and energy wasting processes were increased in liver mitochondria of PC rats. This suggests that liver mitochondria from PC rats request more nutrients than liver mitochondria from control rats to maintain the same ATP production. These alterations were associated to the content and fatty acid composition of cardiolipin.

Dietary polyunsaturated fatty acids and breast cancer risk in Chinese women: a prospective cohort study

Breast cancer is the most common cancer in women. Controversy exists regarding the role of dietary fat in breast cancer etiology. We investigated the association of dietary polyunsaturated fatty acids (PUFAs) and the ratio of n-6 PUFAs to marine-derived n-3 PUFAs with breast cancer risk in the Shanghai Women's Health Study, a prospective cohort study including 72,571 cancer-free participants at baseline. Dietary fatty acid intake was determined using food frequency questionnaires. We used Cox proportional hazards analysis to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for the association of breast cancer risk with dietary fatty acids consumption. In 583,998 person-years of follow-up, we identified 712 breast cancer cases. We found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, α-linolenic acid or marine-derived n-3 PUFA. We found a statistically significant interaction between n-6 PUFA intake, marine-derived n-3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine-derived n-3 PUFA and higher intake (the highest tertile) of n-6 PUFA had an increase risk for breast cancer (RR = 2.06; 95% CI = 1.27-3.34) compared to women with higher intake (the highest tertile) of marine-derived n-3 PUFAs and lower intake (the lowest tertile) of n-6 PUFAs after adjusting for potential confounders. The relative amounts of n-6 PUFA to marine-derived n-3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids.

Role of dietary fatty acids in mammary gland development and breast cancer

Breast cancer is the most common cancer among women worldwide. Estimates suggest up to 35% of cases may be preventable through diet and lifestyle modification. Growing research on the role of fats in human health suggests that early exposure in life to specific fatty acids, when tissues are particularly sensitive to their environment, can have long-term health impacts. The present review examines the role of dietary fat in mammary gland development and breast cancer throughout the lifecycle. Overall, n-3 polyunsaturated fatty acids have promising cancer-preventive effects when introduced early in life, and warrant further research to elucidate the mechanisms of action.

[Effect of lifestyle counseling given by health personnel on the changes in dietary habits of Hungarian women treated for cancer]

The aim of this study was to investigate the changes in dietary habits in women with gynecological or breast cancer, and to analyze the role of some demographic factors, type of the malignant tumor, and the role of medical staff's advice in dietary behavior change of these women, after the diagnosis of cancer. A self-administered questionnaire-based retrospective study was performed, and 155 randomly selected patients, treated for gynecological or breast cancer, were involved. A self-developed questionnaire was used to measure the socio-demographic characteristics, the circumstances of visiting the physician, therapy, present health status and lifestyle before and after the diagnosis of neoplasm. More than three-fourths of the women reported changes in nutrition after the diagnosis of cancer. The consumption of fruits and vegetables increased in the highest proportion (70.3%). Women with higher education changed their diet in higher proportion (p=0.031) compared to women with lower education. Women who were advised to change their lifestyle by their therapists were about four times more likely (OR: 3.87; CI: 1.40-10.69 ) to change their nutrition. Patients with breast cancer changed three times more likely (OR: 3.21; CI: 1.05-9.84) their dietary habits than patients with gynecological cancer. The most influential proven factor to make cancer patients alter their diet was being advised for this by physicians. Thus, our study proved that physicians and nurses have a very important role in changing their cancer patients' nutritional habits into a healthier one.

Cytotoxicity of unsaturated fatty acids in fresh human tumor explants: concentration thresholds and implications for clinical efficacy

Background

Unsaturated fatty acids (UFAs) exhibit in vitro cytotoxicity against many malignant cell lines and yield decreased cancer incidence and reduced tumor growth in animal models. But clinical and animal studies to date have achieved response using only localized delivery methods such as intratumoral infusion. To explore possibilities for enhanced clinical efficacy, fresh surgical explants of tumors from 22 patients with five malignancies were exposed to γ-linolenic acid (GLA) and α-linolenic acid (ALA) and analyzed with an in vitro chemosensitivity testing system, the Fluorescent Cytoprint Assay (FCA). A total of 282 micro-organ cultures derived from these malignant tumors were exposed to GLA and ALA at different concentrations.

Results

GLA and ALA exhibited greater than 90% cytotoxicity at a sharp concentration threshold between 500 μM and 1 mM against all but two malignant micro-organ cultures tested in 5-10% serum. In tests using 30-40% serum, GLA and ALA killed tumor at concentrations of 2 mM and above.

Conclusions

The concentration threshold of 500 μM to 2 mM exhibited for antitumor activity by GLA and ALA is much higher than that observed in most previously reported cell culture studies but consistent with physiological concentrations found to kill tumor clinically and in animals. A mechanism of antitumor activity by unsaturated fatty acids through selective destabilization of the malignant plasma membrane is considered. An oral regimen is proposed for phase I clinical testing that could push the area under the curve for serum concentration of unbound unsaturated fatty acids over time to much higher levels than previously achieved for systemic administration and into the range that could yield antitumor response.

Are all n-3 polyunsaturated fatty acids created equal?

N-3 Polyunsaturated fatty acids have been shown to have potential beneficial effects for chronic diseases including cancer, insulin resistance and cardiovascular disease. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in particular have been studied extensively, whereas substantive evidence for a biological role for the precursor, alpha-linolenic acid (ALA), is lacking. It is not enough to assume that ALA exerts effects through conversion to EPA and DHA, as the process is highly inefficient in humans. Thus, clarification of ALA's involvement in health and disease is essential, as it is the principle n-3 polyunsaturated fatty acid consumed in the North American diet and intakes of EPA and DHA are typically very low. There is evidence suggesting that ALA, EPA and DHA have specific and potentially independent effects on chronic disease. Therefore, this review will assess our current understanding of the differential effects of ALA, EPA and DHA on cancer, insulin resistance, and cardiovascular disease. Potential mechanisms of action will also be reviewed. Overall, a better understanding of the individual role for ALA, EPA and DHA is needed in order to make appropriate dietary recommendations regarding n-3 polyunsaturated fatty acid consumption.

Obesity and breast cancer: the roles of peroxisome proliferator-activated receptor-γ and plasminogen activator inhibitor-1

Breast cancer is the most prominent cancer among females in the United States. There are a number of risk factors associated with development of breast cancer, including consumption of a high-fat diet and obesity. Plasminogen activator inhibitor-1 (PAI-1) is a cytokine upregulated in obesity whose expression is correlated with a poor prognosis in breast cancer. As a key mediator of adipogenesis and regulator of adipokine production, peroxisome proliferator-activated receptor-γ (PPAR-γ) is involved in PAI-1 expression from adipose tissue. We summarize the current knowledge linking PPAR-γ and PAI-1 expression to high-fat diet and obesity in the risk of breast cancer.

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.

Fatty acid uptake by breast cancer cells (MDA-MB-231): effects of insulin, leptin, adiponectin, and TNFalpha

In order to exert metabolic effects, fatty acids must be taken up by cells and metabolize effectively to different classes of cellular lipids (triacylglycerols, phospholipids, etc.) for incorporation into different cellular and intracellular compartments. Therefore, the main aim of the present study is to investigate the uptake and metabolism of fatty acids representing three different series of fatty acids such as oleic acid, 18:1n-9 (OA), arachidonic acid, 20:4n-6 (AA), and eicosapentaneoic acid, 20:5n-3 (EPA) by breast cancer cells, MDA-MB-231. Moreover, we investigated the effects of insulin and several adipokines on the fatty acid uptake by these cells as obesity and insulin resistance syndrome have been suggested to affect breast cancer risk. We report for the first time that AA was predominantly taken up by these cells compared with EPA and OA. Pre-incubation of these cells with TNFalpha stimulated most of the uptake of EPA (30%), whereas uptake of OA and AA was stimulated only 10-15% compared with the controls. Insulin, leptin, and adiponectin had no effect on fatty acid uptake by these cells. Together these results demonstrate that preferential uptake of AA in MDA-MB-231 cells, and the fatty acid uptake activity of these cells is influenced by TNFalpha.

Dietary intakes of omega-6 and omega-3 polyunsaturated fatty acids and the risk of breast cancer

Experimental studies suggest detrimental effects of omega-6 polyunsaturated fatty acids (PUFA), and beneficial effects of omega-3 PUFAs on mammary carcinogenesis, possibly in interaction with antioxidants. However, PUFA food sources are diverse in human diets and few epidemiologic studies have examined whether associations between dietary PUFAs and breast cancer risk vary according to food sources or antioxidant intakes. The relationship between individual PUFA intakes estimated from diet history questionnaires and breast cancer risk was examined among 56,007 French women. During 8 years of follow-up, 1,650 women developed invasive breast cancer. Breast cancer risk was not related to any dietary PUFA overall; however, opposite associations were seen according to food sources, suggesting other potential effects than PUFA per se. Breast cancer risk was inversely associated with alpha-linolenic acid (ALA) intake from fruit and vegetables [highest vs. lowest quintile, hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.63, 0.88; p trend < 0.0001], and from vegetable oils (HR 0.83; 95% CI 0.71, 0.97; p trend 0.017). Conversely, breast cancer risk was positively related to ALA intake from nut mixes (p trend 0.004) and processed foods (p trend 0.068), as was total ALA intake among women in the highest quintile of dietary vitamin E (p trend 0.036). A significant interaction was also found between omega-6 and long-chain omega-3 PUFAs, with breast cancer risk inversely related to long-chain omega-3 PUFAs in women belonging to the highest quintile of omega-6 PUFAs (p interaction 0.042). These results emphasize the need to consider food sources, as well as interactions between fatty acids and with antioxidants, when evaluating associations between PUFA intakes and breast cancer risk.

Erythrocyte fatty acids and risk of proliferative and nonproliferative fibrocystic disease in women in Shanghai, China

BACKGROUND

Although benign breast changes are more common than breast cancer, little evidence regarding risk factors for benign breast conditions is available. Omega-3 (n-3) fatty acids have antiinflammatory and antiproliferative actions and may be important in reducing the risk of benign conditions. There is a lack of research on the association of n-3 fatty acids with risk of benign fibrocystic breast changes.

OBJECTIVES

The objectives of the study were to evaluate the role of n-3 and other fatty acids in the development of benign proliferative fibrocystic conditions (PFCs) and nonproliferative fibrocystic conditions (NPFCs) in the breast and to evaluate the progression of fibrocystic changes in breast cancer.

DESIGN

We conducted a case-control study to determine erythrocyte fatty acid concentrations in 155 women with NPFCs, 185 women with PFCs, 241 women with breast cancer (127 with nonproliferative and 114 with proliferative changes in the noncancerous extratumoral mammary epithelium), and 1,030 control subjects. We estimated the relative risk of NPFCs, PFCs, and breast cancer with proliferative and nonproliferative changes in extratumoral tissue compared with the risk of these changes alone.

RESULTS

Women in the highest quartile of eicosapentaenoic acid concentrations were 67% less likely to have an NPFC alone or with breast cancer and 49% less likely to have breast cancer than were women with PFCs. gamma-Linolenic acid (18:3n-6) was positively associated with all fibrocystic and cancerous conditions. Palmitic:palmitoleic acid (n-7 saturation index) was inversely associated with risk in all comparisons.

CONCLUSION

Our results support a protective effects of n-3 fatty acid intake and the n-7 saturation index against benign fibrocystic breast changes and the progression of proliferative changes to breast cancer.

Cancer patterns in Inuit populations

Inuit people inhabit the circumpolar region, with most living in Alaska, northwest Canada, and Greenland. Although malignant diseases were believed to be almost non-existent in Inuit populations during the beginning of the 20th century, the increasing life expectancy within these populations showed a distinct pattern, characterised by a high risk of Epstein-Barr virus-associated carcinomas of the nasopharynx and salivary glands, and a low risk of tumours common in white populations, including cancer of the prostate, testis, and haemopoietic system. Both genetic and environmental factors seem to be responsible for this pattern. During the second half of the 20th century, Inuit societies underwent major changes in lifestyle and living conditions, and the risk of lifestyle-associated tumours, especially cancers of the lung, colon, and breast, increased considerably after changes in smoking, diet, and reproductive factors. This Review will briefly summarise the current knowledge on cancer epidemiology in Inuit populations, with emphasis on the characteristic Inuit types of cancer.

The lipidome as a composite biomarker of the modifiable part of the risk of breast cancer

The potential for dietary fat to prevent breast cancer makes identification of defined molecules a mandatory step. In order to circumvent the limitations and/or bias of dietary exposure assessment tools, we have used the fatty acid composition of white adipose tissue as biomarker of past lipid intake. When considered separately, candidate fatty acids identified as favourable on the basis of their association with breast cancer risk have usually led to inconsistent results in dietary intervention studies carried out in rats. This inconsistency indicates that any approach based on a single fatty acid should be abandoned for an integrated view over the complex lipid interactions, which finally determines the lipidome, the lipid profile that is found in individuals. We reappraised the role of the complete lipid profile through a comprehensive study of adipose tissue fatty acids obtained in patients with benign or malignant breast tumors. Rather than a single fatty acid, a composite indicator combining elevated monounsaturates and low n-6/n-3 fatty acid ratio was associated with decreased breast cancer risk. The lipidome may provide the opportunity to quantify the modifiable part of the risk of breast cancer. The lipidome may be used as a template for designing proper dietary modifications in order to delay the occurrence of breast cancer. Which dietary modifications should be undertaken in order to bring a pertinent change to the lipidome with respect to the risk of breast cancer is currently unknown. The lipidome may allow the individualization of a high risk population of women, who may be targeted for a dietary prevention of breast cancer. The setting and validation of a high-throughput lipidomic station with analytical capabilities fitted to the need of mass screening is required. These two locks must be resolved before a primary prevention of breast cancer by diet could be contemplated.

Effects of krill oil on serum lipids of hyperlipidemic rats and human SW480 cells

BACKGROUND

Cardiovascular disease (CVD) and colon cancer incidence are known to be closely related to dietary factors. This article evaluated effects of krill oil (KO) on serum lipids of hyperlipidemia rats and human colon cancer cells (SW480). Serum lipids of rats fed with high fat diet (HFD) and different doses of KO were measured by automatic analyzer. Effect of KO on viability of cells was determined by methyl thiazolyl tetrazolium (MTT) assay.

RESULTS

Except for higher dose group, body weights decreased significantly. Total cholesterol (TC), LDL-cholesterol (LDL-C) of all dose groups, Triglycerides (TG) of low and mid dose groups descended significantly, while there were no significant differences of HDL-cholesterol (HDL-C), compared with control group. Treatment of colon cancer cells with KO also resulted in time-dependent inhibition of cell growth.

CONCLUSION

Our findings indicated that the consumption of KO may provide benefits to control serum lipid levels in certain diseases and inhibit growth of colon cancer cells. Therefore, KO may be a good candidate for development as a functional food and nutraceutical.