Plant foods, plasma enterolactone and breast cancer - with a focus on estrogen receptor status and genetic variation

Diets high in fibre have previously been associated with decreased risk of breast cancer in the Malmö Diet and Cancer cohort. Several potent compounds may exist in high-fibre diets that might protect against breast cancer, for example lignans. Plant lignans are converted to enterolactone by the gut microflora and are similar in structure to estrogens. Enterolactone may interact with the estrogen receptors (ERs) and, therefore, inhibit the effect of estrogens. The aim of this doctoral project was to prospectively examine if plant food intakes and enterolactone blood concentrations were associated with breast cancer, and to examine if the association differed depending on ER status of the tumours or variation in the ER genes. Information (including high validity dietary data) from the Malmö Diet and Cancer cohort with baseline examinations from 1991 to 1996 was used. Among 15,773 women, 45-73 years at baseline, without prevalent cancer, 544 women were diagnosed with breast cancer until 31 December 2004. High intakes of high-fibre bread were associated with decreased risk of breast cancer. When restricting the analyses to individuals with suggested more stable food habits, a decreased breast cancer risk were also observed with high intakes of fruit, berries and vegetables. High-fibre bread and fruit and berries were the main dietary determinants of enterolactone concentration. In addition, obesity and smoking was associated with lower enterolactone concentrations. High enterolactone concentrations (>16 nmol/L) was associated with decreased breast cancer risk. When stratifying for fibre intake, a decreased breast cancer risk with high enterolactone concentration was only observed among individuals with high fibre intakes. Relatively high variation of enterolactone within and between individuals was observed; the association between enterolactone and risk of breast cancer is likely attenuated. The reduced breast cancer risk with high enterolactone concentrations was only observed for ERα-positive and ERβ-negative tumours. Breast cancer risk was not significantly associated with any of the selected polymorphisms in the ERα and ERβ genes. However, the protective effect of high enterolactone concentration was seen in subgroups of the individuals with specific genetic variants, and a tendency towards an interaction between a polymorphism in intron 3 of the ERα gene and enterolactone concentrations was observed. In conclusion, a high-fibre diet including high-fibre bread, fruit, berries and vegetables will likely reduce the risk of breast cancer in middle aged and older women. The protective effect of a high-fibre diet might be due to its content of lignans

Genetic variation in the fat mass and obesity-associated gene (FTO) in association with food preferences in healthy adults.

Earlier studies have indicated that the fat mass and obesity-associated gene (FTO) is not only associated with BMI and weight but also with appetite and dietary intake

Intake levels of dietary long-chain PUFAs modify the association between genetic variation in FADS and LDL-C

Polymorphisms of the FA desaturase (FADS) gene cluster have been associated with LDL, HDL, and triglyceride concentrations. Because FADS converts alpha-linolenic acid (ALA) and linoleic acid into PUFAs, we investigated the interaction between different PUFA intakes and the FADS polymorphism rs174547 (T>C) on fasting blood lipid and lipoprotein concentrations. We included 4,635 individuals (60% females, 45-68 years) from the Swedish population-based Malmo Diet and Cancer cohort. Dietary intakes were assessed by a modified diet history method including 7-day registration of cooked meals. The C-allele of rs174547 was associated with lower LDL concentration (P = 0.03). We observed significant interaction between rs174547 and long-chain omega-3 PUFA intakes on LDL (P = 0.01); the C-allele was only associated with lower LDL among individuals in the lowest tertile of long-chain omega-3 PUFA intakes (P < 0.001). In addition, significant interaction was observed between rs174547 and the ratio of ALA and linoleic FA intakes on HDL (P = 0.03). However, no significant associations between the C-allele and HDL were detected within the intake tertiles of the ratio. Our findings suggest that dietary intake levels of different PUFAs modify the associated effect of genetic variation in FADS on LDL and HDL.-Hellstrand, S., E. Sonestedt, U. Ericson, B. Gullberg, E. Wirfalt, B. Hedblad, and M. Orho-Melander. Intake levels of dietary PUFAs modify the association between genetic variation in FADS and LDL-C. J. Lipid Res. 2012. 53: 1183-1189

Development of a diet quality index assessing adherence to the Swedish nutrition recommendations and dietary guidelines in the Malmö Diet and Cancer cohort.

OBJECTIVE: To develop a diet quality index (DQI) that assesses adherence to the Swedish nutrition recommendations (SNR) and the Swedish dietary guidelines (SDG). DESIGN: A cross-sectional study within the Malmö Diet and Cancer (MDC) cohort. A diet history method collected dietary data, a structured questionnaire lifestyle and socio-economic information, and anthropometric data were collected by direct measurements. The index (DQI-SNR) included six components: SFA, PUFA, fish and shellfish, dietary fibre, fruit and vegetables, and sucrose. SETTING: Malmö, Sweden. SUBJECTS: Men (n 4525) and women (n 8491) of the MDC cohort enrolled from September 1994 to October 1996. RESULTS: For participants with high DQI-SNR scores, nutrient and food intakes were close to recommendations. However, most of the study population exceeded the recommended intake for SFA (98 %) and few reached recommended intakes for dietary fibre (24 %), fruit and vegetables (32 %), vitamin D (18 %) and folate (2 %). A high DQI-SNR score was positively associated with age, physical activity, not smoking, past food habit change, education and socio-economic status. Individuals with high scores were more likely to have a diabetes diagnosis or experienced a cardiovascular event. CONCLUSIONS: Results suggest that the DQI-SNR is a useful tool for assessing adherence to the SNR 2005 and the SDG in the MDC cohort. No index has previously been developed with the aim of evaluating adherence to the current dietary recommendations in Sweden. Further validation of the DQI-SNR, and evaluation of its utility, is needed

Plasma enterolactone and risk of prostate cancer in middle-aged Swedish men

Enterolactone (ENL) is formed in the human gut after consumption of lignans, has estrogenic properties, and has been associated with risk of prostate cancer. We examined the association between plasma ENL levels and prostate cancer in a nested case-control study within the population-based Malmo Diet and Cancer cohort. We also examined the association between plasma ENL and dietary and lifestyle factors. The study population consisted of 1010 cases occurring during a mean follow-up of 14.6 years, and 1817 controls matched on age and study entry date. We used national registers (95%) and hospital records (5%) to ascertain cases. Diet was estimated by a modified diet history method. Plasma ENL concentrations were determined by a time-resolved fluoroimmunoassay. Odds ratios were calculated by unconditional logistic regression. There were no significant associations between plasma ENL and incidence of all prostate cancer (odds ratio 0.99 [95% confidence interval 0.77-1.280] for the highest ENL quintile versus lowest, p for trend 0.66). However, in certain subgroups of men, including men with abdominal obesity (p for interaction = 0.012), we observed associations between high ENL levels and lower odds of high-risk prostate cancer. Plasma ENL was positively associated with consumption of high-fibre bread, fruit, tea, and coffee; with age, and with height, while it was negatively associated with smoking and waist circumference; however, although significant, all associations were rather weak (r ae |0.14|). ENL concentration was not consistently associated with lower prostate cancer risk, although it was weakly associated with a healthy lifestyle.Peer reviewe

Genetic Determinants of Long-Term Changes in Blood Lipid Concentrations: 10-Year Follow-Up of the GLACIER Study

Recent genome-wide meta-analyses identified 157 loci associated with cross-sectional lipid traits. Here we tested whether these loci associate (singly and in trait-specific genetic risk scores [GRS]) with longitudinal changes in total cholesterol (TC) and triglyceride (TG) levels in a population-based prospective cohort from Northern Sweden (the GLACIER Study). We sought replication in a southern Swedish cohort (the MDC Study; N = 2,943). GLACIER Study participants (N = 6,064) were genotyped with the MetaboChip array. Up to 3,495 participants had 10-yr follow-up data available in the GLACIER Study. The TC- and TG-specific GRSs were strongly associated with change in lipid levels (β = 0.02 mmol/l per effect allele per decade follow-up, P = 2.0×10−11 for TC; β = 0.02 mmol/l per effect allele per decade follow-up, P = 5.0×10−5 for TG). In individual SNP analysis, one TC locus, apolipoprotein E (APOE) rs4420638 (β = 0.12 mmol/l per effect allele per decade follow-up, P = 2.0×10−5), and two TG loci, tribbles pseudokinase 1 (TRIB1) rs2954029 (β = 0.09 mmol/l per effect allele per decade follow-up, P = 5.1×10−4) and apolipoprotein A-I (APOA1) rs6589564 (β = 0.31 mmol/l per effect allele per decade follow-up, P = 1.4×10−8), remained significantly associated with longitudinal changes for the respective traits after correction for multiple testing. An additional 12 loci were nominally associated with TC or TG changes. In replication analyses, the APOE rs4420638, TRIB1 rs2954029, and APOA1 rs6589564 associations were confirmed (P≤0.001). In summary, trait-specific GRSs are robustly associated with 10-yr changes in lipid levels and three individual SNPs were strongly associated with 10-yr changes in lipid levels

Dietary Fiber and Saturated Fat Intake Associations with Cardiovascular Disease Differ by Sex in the Malmö Diet and Cancer Cohort: A Prospective Study

BACKGROUND: The aim of the study was to examine associations between intake of macronutrients and dietary fiber and incident ischemic cardiovascular disease (iCVD) in men and women. METHODS: We used data from 8,139 male and 12,535 female participants (aged 44-73 y) of the Swedish population-based Malmö Diet and Cancer cohort. The participants were without history of CVD and diabetes mellitus, and had reported stable dietary habits in the study questionnaire. Diet was assessed by a validated modified diet history method, combining a 7-d registration of cooked meals and cold beverages, a 168-item food questionnaire (covering other foods and meal patterns), and a 1-hour diet interview. Sociodemographic and lifestyle data were collected by questionnaire. iCVD cases, which included coronary events (myocardial infarctions or deaths from chronic ischemic heart disease) and ischemic strokes, were ascertained via national and local registries. Nutrient-disease associations were examined by multivariate Cox regressions. RESULTS: During a mean follow-up of 13.5 years, we identified 1,089 male and 687 female iCVD cases. High fiber intakes were associated with lower incidence rates of iCVD in women and of ischemic stroke in men. In post-hoc analysis, we discovered statistically significant interactions between intake of fiber and saturated fat; these interactions also differed between men and women (p<0.001). CONCLUSIONS: In this well-defined population, a high fiber intake was associated with lower risk of iCVD, but there were no robust associations between other macronutrients and iCVD risk. Judging from this study, gender-specific nutrient analysis may be preferable in epidemiology