A Sustainability Compass for policy navigation to sustainable food systems.

Growing acknowledgement that food systems require transformation, demands comprehensive sustainability assessments that can support decision-making and sustainability governance. To do so, assessment frameworks must be able to make trade-offs and synergies visible and allow for inclusive negotiation on food system outcomes relevant to diverse food system actors. This paper reviews literature and frameworks and builds on stakeholder input to present a Sustainability Compass made up of a comprehensive set of metrics for food system assessments. The Compass defines sustainability scores for four societal goals, underpinned by areas of concern. We demonstrate proof of concept of the operationalization of the approach and its metrics. The Sustainability Compass is able to generate comprehensive food system insights that enables reflexive evaluation and multi-actor negotiation for policy making.

Methodological Aspects of Diet Quality Indicators in Childhood: A Mapping Review.

Diet quality indicators (DQIns) are tools that aim to assess an individual's overall diet quality. Previous reviews focused mainly on health-related outcomes but did not provide detailed information about components, assessment variables, or important methodological issues for the development and application of DQIns in the pediatric age. The current mapping review aims to provide comprehensive guidance regarding DQIns developed through a priori methodology in children aged ≤14 y that have been applied worldwide. A mapping review was conducted, whereby 1665 original articles describing the development, modifications, and updates of DQIns, published up to June 26, 2020, in English and Spanish, were retrieved. A total of 139 articles were identified and classified into 13 subgroups. There were 10 overall DQIns: Healthy Eating Indexes (n = 25), Dietary Diversity Scores (n = 20), Diet Quality Indexes (n = 16), Food Variety Scores (n = 11), Healthy and Unhealthy Scores (n = 11), Feeding and Eating Indexes (n = 10), Diet Quality Scores (n = 5), Nutritional Adequacy and Micronutrients Indexes (n = 5), Dietary Guidelines Indexes (n = 5), and Other Healthy Diet Indexes (n = 13). Three additional subgroups of dietary and lifestyle indicators found were Mediterranean Diet Indexes (n = 10), Diet-Lifestyle Indexes (n = 5), and Breakfast Quality Indexes (n = 3). This compilation of DQIns will help researchers select the most appropriate tool for future epidemiological studies by considering a careful selection of information about the assessment components, scoring methods, and key methodological issues. The main limitations of this review are that, due to its nature, a risk-of-bias assessment was not performed and the article screening was completed in 2 databases (PubMed/MEDLINE and Scopus). More research is needed to identify health-related outcomes associated with DQIns in the pediatric population, using clearer and more standardized methodological criteria.

Improving health and carbon footprints of European diets using a benchmarking approach.

OBJECTIVE: This study aimed to identify diets with improved nutrient quality and environmental impact within the boundaries of dietary practices. DESIGN: We used Data Envelopment Analysis to benchmark diets for improved adherence to food-based dietary guidelines (FBDG). We then optimised these diets for dietary preferences, nutrient quality and environmental impact. Diets were evaluated using the Nutrient Rich Diet score (NRD15.3), diet-related greenhouse gas emission (GHGE) and a diet similarity index that quantified the proportion of food intake that remained similar as compared with the observed diet. SETTING: National dietary surveys of four European countries (Denmark, Czech Republic, Italy and France). SUBJECTS: Approximately 6500 adults, aged 18-64 years. RESULTS: When dietary preferences were prioritised, NRD15·3 was ~6 % higher, GHGE was ~4 % lower and ~85 % of food intake remained similar. This diet had higher amounts of fruit, vegetables and whole grains than the observed diet. When nutrient quality was prioritised, NRD15·3 was ~16 % higher, GHGE was ~3 % lower and ~72 % of food intake remained similar. This diet had higher amounts of legumes and fish and lower amounts of sweetened and alcoholic beverages. Finally, when environmental impact was prioritised, NRD15·3 was ~9 % higher, GHGE was ~21 % lower and ~73 % of food intake remained similar. In this diet, red and processed meat partly shifted to either eggs, poultry, fish or dairy. CONCLUSIONS: Benchmark modelling can generate diets with improved adherence to FBDG within the boundaries of dietary practices, but fully maximising health and minimising GHGE cannot be achieved simultaneously.

SHARP-Indicators Database towards a public database for environmental sustainability.

To initiate the achievement of an European-wide applicable public database for indicators of environmental sustainability of the diet, we developed the SHARP Indicators Database (SHARP-ID). A comprehensive description of the development of the SHARP-ID is provided in this article. In the SHARP-ID, environmental impact assessment was based on attributional life cycle analyses using environmental indicators greenhouse gas emission (GHGE) and land use (LU). Life cycle inventory data of 182 primary products were combined with data on production, trade and transport, and adjusted for consumption amount using conversions factors for production, edible portion, cooking losses and gains, and for food losses and waste in order to derive estimates of GHGE and LU for the foods as eaten. Extrapolations based on similarities in type of food, production system and ingredient composition were made to obtain estimates of GHGE and LU per kg of food as eaten for 944 food items coded with a unique FoodEx2-code of EFSA and consumed in four European countries, i.e. Denmark, Czech Republic, Italy and France. This LCA-food-item database can be linked to food intake data collected at the individual level in order to calculate the environmental impact of individual's diets. The application of this database to European survey data is described in an original research article entitled "Dietary choices and environmental impact in four European countries" (Mertens et al., 2019).

Diet quality indices for research in low- and middle-income countries: a systematic review.

CONTEXT: Dietary intake research has increasingly focused on improving diet quality in low- and middle-income countries (LMICs). Accompanying this is the need for sound metrics to assess diet quality. OBJECTIVE: This systematic literature review aims to describe existing diet quality indices for general populations and highlights recommendations for developing such indices for food system research in LMICs. DATA SOURCES: Three electronic databases were searched for papers published between January 2008 and December 2017. DATA EXTRACTION: Articles published in English and describing the development of an index to measure overall diet quality, irrespective of whether they were for high-income countries or LMICs, were included. DATA ANALYSIS: Eighty-one indices were identified, over two thirds were based on national dietary guidelines from high-income countries. Of the 3 key diet quality dimensions, "diversity" was included in all 18 indices developed for LMICs, "moderation" was captured by most, and "nutrient adequacy" was included 4 times. CONCLUSIONS: Indices need to be developed that include all dimensions, include foods and/or food groups rather than nutrients, use an optimal range for individual components in the score, and express the intake of healthy and unhealthy components separately. Importantly, validation of the index should be part of its development.

FFQ versus repeated 24-h recalls for estimating diet-related environmental impact.

BACKGROUND: There is an increasing interest in estimating environmental impact of individuals' diets by using individual-level food consumption data. However, like assessment of nutrient intakes, these data are prone to substantial measurement errors dependent on the method of dietary assessment, and this often result in attenuation of associations. PURPOSE: To investigate the performance of a food frequency questionnaire (FFQ) for estimating the environmental impact of the diet as compared to independent 24-h recalls (24hR), and to study the association between environmental impact and dietary quality for the FFQ and 24hR. METHODS: We analysed cross-sectional data from 1169 men and women, aged 20-76 years, who participated in the NQplus study, the Netherlands. They completed a 216-item FFQ and two replicates of web-based 24hR. Life cycle assessments of 207 food products were used to calculate greenhouse gas emissions, fossil energy and land use, summarised into an aggregated score, pReCiPe. Validity of the FFQ was evaluated against 24hRs using correlation coefficients and attenuation coefficients. Associations with dietary quality were based on Dutch Healthy Diet 15-index (DHD15-index) and Nutrient Rich Diet score (NRD9.3). RESULTS: For pReCiPe, correlation coefficient between FFQ and 24hR was 0.33 when adjusted for covariates age, gender and BMI, and increased to 0.76 when de-attenuated for within-subject variation in the 24hR. Energy-adjustment slightly reduced these correlations (r = 0.71 for residuals of observed values and 0.59 for residuals of density values). Covariate-adjusted attenuation coefficient for the FFQ was 0.56 (ʎ1 = 0.56 and ʎ1 = 0.65 for observed and density residuals), slightly lower than without covariate adjustment. Diet-related environmental impact was inversely associated with the food-based DHD15-index for both FFQ and 24hR, while associations with the nutrient-based NRD9.3 were inconsistent. CONCLUSIONS: The FFQ slightly underestimated environmental impact when compared to 24hR. Associations with dietary quality are highly dependent on the diet score used, and less dependent on the method of dietary assessment.

Geographic and socioeconomic diversity of food and nutrient intakes: a comparison of four European countries.

PURPOSE: Public health policies and actions increasingly acknowledge the climate burden of food consumption. The aim of this study is to describe dietary intakes across four European countries, as baseline for further research towards healthier and environmentally-friendlier diets for Europe. METHODS: Individual-level dietary intake data in adults were obtained from nationally-representative surveys from Denmark and France using a 7-day diet record, Italy using a 3-day diet record, and Czech Republic using two replicates of a 24-h recall. Energy-standardised food and nutrient intakes were calculated for each subject from the mean of two randomly selected days. RESULTS: There was clear geographical variability, with a between-country range for mean fruit intake from 118 to 199 g/day, for vegetables from 95 to 239 g/day, for fish from 12 to 45 g/day, for dairy from 129 to 302 g/day, for sweet beverages from 48 to 224 ml/day, and for alcohol from 8 to 15 g/day, with higher intakes in Italy for fruit, vegetables and fish, and in Denmark for dairy, sweet beverages and alcohol. In all countries, intakes were low for legumes (< 20 g/day), and nuts and seeds (< 5 g/day), but high for red and processed meat (> 80 g/day). Within countries, food intakes also varied by socio-economic factors such as age, gender, and educational level, but less pronounced by anthropometric factors such as overweight status. For nutrients, intakes were low for dietary fibre (15.8-19.4 g/day) and vitamin D (2.4-3.0 µg/day) in all countries, for potassium (2288-2938 mg/day) and magnesium (268-285 mg/day) except in Denmark, for vitamin E in Denmark (6.7 mg/day), and for folate in Czech Republic (212 µg/day). CONCLUSIONS: There is considerable variation in food and nutrient intakes across Europe, not only between, but also within countries. Individual-level dietary data provide insight into the heterogeneity of dietary habits beyond per capita food supply data, and this is crucial to balancing healthy and environmentally-friendly diets for European citizens.

Operationalising the health aspects of sustainable diets: a review.

OBJECTIVE: Shifting towards a more sustainable food consumption pattern is an important strategy to mitigate climate change. In the past decade, various studies have optimised environmentally sustainable diets using different methodological approaches. The aim of the present review was to categorise and summarise the different approaches to operationalise the health aspects of environmentally sustainable diets. DESIGN: Conventional keyword and reference searches were conducted in PubMed, Scopus, Web of Knowledge and CAB Abstracts. Inclusion criteria were: (i) English-language publication; (ii) published between 2005 and October 2015; (iii) dietary data collected for the diet as a whole at the national, household or individual level; (iv) comparison of the current diet with dietary scenarios; and (v) for results to consider the health aspect in some way. SETTING: Consumer diets. SUBJECTS: Adult population. RESULTS: We reviewed forty-nine studies that combined the health and environmental aspects of consumer diets. Hereby, five approaches to operationalise the health aspect of the diet were identified: (i) food item replacements; (ii) dietary guidelines; (iii) dietary quality scores; (iv) diet modelling techniques; and (v) diet-related health impact analysis. CONCLUSIONS: Although the sustainability concept is increasingly popular and widely advocated by nutritional and environmental scientists, the journey towards designing sustainable diets for consumers has only just begun. In the context of operationalising the health aspects, diet modelling might be considered the preferred approach since it captures the complexity of the diet as a whole. For the future, we propose SHARP diets: environmentally Sustainable (S), Healthy (H), Affordable (A), Reliable (R) and Preferred from the consumer's perspective (P).

Adapted dietary inflammatory index and its association with a summary score for low-grade inflammation and markers of glucose metabolism: the Cohort study on Diabetes and Atherosclerosis Maastricht (CODAM) and the Hoorn study.

BACKGROUND: Diet may be associated with the development of type 2 diabetes through its effects on low-grade inflammation. OBJECTIVES: We investigated whether an adapted dietary inflammatory index (ADII) is associated with a summary score for low-grade inflammation and markers of glucose metabolism. In addition, we investigated the mediating role of inflammation in the association between ADII and markers of glucose metabolism. DESIGN: We performed cross-sectional analyses of 2 Dutch cohort studies (n= 1024). An ADII was obtained by multiplying standardized energy-adjusted intakes of dietary components by literature-based dietary inflammatory weights that reflected the inflammatory potential of components. Subsequently, these multiplications were summed. Six biomarkers of inflammation were compiled in a summary score. Associations of the ADII (expressed per SD) with the summary score for inflammation and markers of glucose metabolism were investigated by using multiple linear regression models. Inflammation was considered a potential mediator in the analysis with markers of glucose metabolism. RESULTS: A higher ADII was associated with a higher summary score for inflammation [ß-adjusted = 0.04 per SD (95% CI: 0.01, 0.07 per SD)]. The ADII was also adversely associated with insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR): ß-adjusted = 3.5% per SD (95% CI: 0.6%, 6.3% per SD)]. This association was attenuated after the inclusion of the summary score for inflammation [ß-adjusted+inflammation = 2.2% (95% CI: -0.6%, 5.0%)]. The ADII was also adversely associated with fasting glucose and postload glucose but not with glycated hemoglobin. CONCLUSION: The significant mediating role of low-grade inflammation in the association between the ADII and HOMA-IR suggests that inflammation might be one of the pathways through which diet affects insulin resistance.

Dietary glycemic index, glycemic load, and digestible carbohydrate intake are not associated with risk of type 2 diabetes in eight European countries.

The association of glycemic index (GI) and glycemic load (GL) with the risk of type 2 diabetes remains unclear. We investigated associations of dietary GI, GL, and digestible carbohydrate with incident type 2 diabetes. We performed a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition Study, including a random subcohort (n = 16,835) and incident type 2 diabetes cases (n = 12,403). The median follow-up time was 12 y. Baseline dietary intakes were assessed using country-specific dietary questionnaires. Country-specific HR were calculated and pooled using random effects meta-analysis. Dietary GI, GL, and digestible carbohydrate in the subcohort were (mean ± SD) 56 ± 4, 127 ± 23, and 226 ± 36 g/d, respectively. After adjustment for confounders, GI and GL were not associated with incident diabetes [HR highest vs. lowest quartile (HR(Q4)) for GI: 1.05 (95% CI = 0.96, 1.16); HR(Q4) for GL: 1.07 (95% CI = 0.95, 1.20)]. Digestible carbohydrate intake was not associated with incident diabetes [HR(Q4): 0.98 (95% CI = 0.86, 1.10)]. In additional analyses, we found that discrepancies in the GI value assignment to foods possibly explain differences in GI associations with diabetes within the same study population. In conclusion, an expansion of the GI tables and systematic GI value assignment to foods may be needed to improve the validity of GI values derived in such studies, after which GI associations may need reevaluation. Our study shows that digestible carbohydrate intake is not associated with diabetes risk and suggests that diabetes risk with high-GI and -GL diets may be more modest than initial studies suggested.

Tea consumption and incidence of type 2 diabetes in Europe: the EPIC-InterAct case-cohort study.

BACKGROUND: In previous meta-analyses, tea consumption has been associated with lower incidence of type 2 diabetes. It is unclear, however, if tea is associated inversely over the entire range of intake. Therefore, we investigated the association between tea consumption and incidence of type 2 diabetes in a European population. METHODOLOGY/PRINCIPAL FINDINGS: The EPIC-InterAct case-cohort study was conducted in 26 centers in 8 European countries and consists of a total of 12,403 incident type 2 diabetes cases and a stratified subcohort of 16,835 individuals from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Country-specific Hazard Ratios (HR) for incidence of type 2 diabetes were obtained after adjustment for lifestyle and dietary factors using a Cox regression adapted for a case-cohort design. Subsequently, country-specific HR were combined using a random effects meta-analysis. Tea consumption was studied as categorical variable (0, >0-<1, 1-<4, ≥ 4 cups/day). The dose-response of the association was further explored by restricted cubic spline regression. Country specific medians of tea consumption ranged from 0 cups/day in Spain to 4 cups/day in United Kingdom. Tea consumption was associated inversely with incidence of type 2 diabetes; the HR was 0.84 [95%CI 0.71, 1.00] when participants who drank ≥ 4 cups of tea per day were compared with non-drinkers (p(linear trend) = 0.04). Incidence of type 2 diabetes already tended to be lower with tea consumption of 1-<4 cups/day (HR = 0.93 [95%CI 0.81, 1.05]). Spline regression did not suggest a non-linear association (p(non-linearity) = 0.20). CONCLUSIONS/SIGNIFICANCE: A linear inverse association was observed between tea consumption and incidence of type 2 diabetes. People who drink at least 4 cups of tea per day may have a 16% lower risk of developing type 2 diabetes than non-tea drinkers.

Meat consumption and its association with C-reactive protein and incident type 2 diabetes: the Rotterdam Study.

OBJECTIVE: To investigate whether intake of different types of meat is associated with circulating C-reactive protein (CRP) and risk of type 2 diabetes in a prospective cohort study. RESEARCH DESIGN AND METHODS: Our analysis included 4,366 Dutch participants who did not have diabetes at baseline. During a median follow-up period of 12.4 years, 456 diabetes cases were confirmed. Intake of red meat, processed meat, and poultry was derived from a food frequency questionnaire, and their association with serum high-sensitivity CRP was examined cross-sectionally using linear regression models. Their association with risk of type 2 diabetes was examined using multivariate Cox proportional hazards model, including age, sex, family history of diabetes, and lifestyle and dietary factors. RESULTS: An increment of 50 g of processed meat was associated with increased CRP concentration (ß(processed meat) = 0.12; P = 0.01), whereas intake of red meat and poultry was not. When comparing the highest to the lowest category of meat intake with respect to diabetes incidence, the adjusted relative risks were as follows: for red meat (1.42 [95% CI 1.06-1.91]), for processed meat (1.87 [1.26-2.78]), and for poultry (0.95 [0.74-1.22]). Additional analysis showed that the associations were not affected appreciably after inclusion of CRP into the model. After adjustment for BMI, however, the association for red meat attenuated to 1.18 (0.88-1.59). CONCLUSIONS: Intake of processed meat is associated with higher risk of type 2 diabetes. It appears unlikely that CRP mediates this association.

The prospective association between total and type of fish intake and type 2 diabetes in 8 European countries: EPIC-InterAct Study.

BACKGROUND: Epidemiologic evidence of an association between fish intake and type 2 diabetes (T2D) is inconsistent and unresolved. OBJECTIVE: The objective was to examine the association between total and type of fish intake and T2D in 8 European countries. DESIGN: This was a case-cohort study, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) study, with 3.99 million person-years of follow-up, 12,403 incident diabetes cases, and a random subcohort of 16,835 individuals from 8 European countries. Habitual fish intake (lean fish, fatty fish, total fish, shellfish, and combined fish and shellfish) was assessed by country-specific dietary questionnaires. HRs were estimated in each country by using Prentice-weighted Cox regression models and pooled by using a random-effects meta-analysis. RESULTS: No overall association was found between combined fish and shellfish intake and incident T2D per quartile (adjusted HR: 1.00; 95% CI: 0.94, 1.06; P-trend = 0.99). Total fish, lean fish, and shellfish intakes separately were also not associated with T2D, but fatty fish intake was weakly inversely associated with T2D: adjusted HR per quartile 0.97 (0.94, 1.00), with an HR of 0.84 (0.70, 1.01), 0.85 (0.76, 0.95), and 0.87 (0.78, 0.97) for a comparison of the second, third, and fourth quartiles with the lowest quartile of intake, respectively (P-trend = 0.06). CONCLUSIONS: These findings suggest that lean fish, total fish, and shellfish intakes are not associated with incident diabetes but that fatty fish intake may be weakly inversely associated. Replication of these findings in other populations and investigation of the mechanisms underlying these associations are warranted. Meanwhile, current public health recommendations on fish intake should remain unchanged.

Glycemic index and glycemic load and their association with C-reactive protein and incident type 2 diabetes.

Objective. To investigate whether the Glycemic Index (GI) or Glycemic Load (GL) of a diet is associated with C-reactive Protein (CRP) and risk of type 2 diabetes in a prospective study. Materials and Methods. Our analysis included 4,366 participants who did not have diabetes at baseline. During follow-up 456 diabetes cases were confirmed. Dietary GI and GL were derived from a food-frequency questionnaire and its association with CRP was examined cross-sectionally using linear regression models. The association of GI and GL with diabetes incidence was examined using Cox proportional hazard models. Results. GL, but not GI, was associated with lnCRP at baseline (b(GL) = 0.11 per 50 units; P = .01). When comparing the highest to the lowest tertile of GI with respect to diabetes incidence, a Relative Risk (RR) of 0.95 [95%CI 0.75, 1.21] was found after adjustment for lifestyle and nutritional factors. For GL the RR for diabetes incidence was 1.00 [95%CI 0.74, 1.36]. Additional adjustment for CRP did not change RRs. Conclusion. Since GI was not associated with CRP and risk of type 2 diabetes, it is unlikely that a high GI diet induces the previously shown positive association between CRP and risk of type 2 diabetes by increasing CRP concentrations.

Eating fish and risk of type 2 diabetes: A population-based, prospective follow-up study.

OBJECTIVE: To investigate the relation between total fish, type of fish (lean and fatty), and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake and risk of type 2 diabetes in a population-based cohort. RESEARCH DESIGN AND METHODS: The analysis included 4,472 Dutch participants aged >or=55 years without diabetes at baseline. Dietary intake was assessed with a semiquantitative food frequency questionnaire. Hazard ratios (relative risk [RR]) with 95% CIs were used to examine risk associations adjusted for age, sex, lifestyle, and nutritional factors. RESULTS: After 15 years of follow-up, 463 participants developed type 2 diabetes. Median fish intake, mainly lean fish (81%), was 10 g/day. Total fish intake was associated positively with risk of type 2 diabetes; the RR was 1.32 (95% CI 1.02-1.70) in the highest total fish group (>or=28 g/day) compared with that for non-fish eaters (P(trend) = 0.04). Correspondingly, lean fish intake tended to be associated positively with type 2 diabetes (RR highest group [>or=23 g/day] 1.30 [95% CI 1.01-1.68]; P(trend) = 0.06), but fatty fish was not. No association was observed between EPA and DHA intake and type 2 diabetes (RR highest group [>or=149.4 mg/day] 1.22 [0.97-1.53]). With additional adjustment for intake of selenium, cholesterol, and vitamin D, this RR decreased to 1.05 (0.80-1.38; P(trend) = 0.77). CONCLUSIONS: The findings do not support a beneficial effect of total fish, type of fish, or EPA and DHA intake on the risk of type 2 diabetes. Alternatively, other dietary components, such as selenium, and unmeasured contaminants present in fish might explain our results.

Plasma enterolignans are not associated with nonfatal myocardial infarction risk.

Plant lignans present in foods such as whole grains, seeds and nuts, fruits and vegetables, and beverages. Plant lignans are converted by intestinal bacteria into the enterolignans enterodiol and enterolactone. Up to now, epidemiological evidence for a protective role of enterolignans on cardiovascular diseases is limited and inconsistent. We investigated the association between plasma enterodiol and enterolactone and nonfatal myocardial infarction risk in a prospective study. During follow-up (1987-1998) of 15,107 subjects, aged 20-59 years, 236 incident nonfatal myocardial infarction cases were diagnosed. Controls (n=283) were frequency matched to the cases on age, sex, and study center. No statistically significant associations between plasma enterodiol and enterolactone and risk of nonfatal myocardial infarction were detected. The odds ratio for the highest versus the lowest quartile of enterodiol was 1.21 (95% confidence interval (CI): 0.70, 2.12; p for trend=0.74), and that of enterolactone 1.51 (95% CI: 0.87, 2.61; p for trend=0.12) after adjustment for known dietary risk factors for coronary heart disease. No effect modification was observed for sex, menopausal status, or smoking status. Our results do not support the hypothesis that high plasma enterodiol or enterolactone concentrations are associated with a reduced risk of nonfatal myocardial infarction.

Plasma enterolignan concentrations and colorectal cancer risk in a nested case-control study.

Enterolignans are biphenolic compounds that possess several biologic activities whereby they may influence carcinogenesis. The authors investigated the association between plasma enterolactone and enterodiol and colorectal cancer risk in a Dutch prospective study. Among more than 35,000 participants aged 20-59 years, 160 colorectal cancer cases were diagnosed after 7.5 years of follow-up (1987-2003). Cohort members who were frequency-matched to the cases on age, sex, and study center were selected as controls (n = 387). Plasma enterodiol and enterolactone were not associated with risk of colorectal cancer after adjustment for known colorectal cancer risk factors (highest quartile vs. lowest: for enterodiol, odds ratio = 1.11, 95% confidence interval: 0.56, 2.20 (p-trend = 0.75); for enterolactone, odds ratio = 1.70, 95% confidence interval: 0.88, 3.27 (p-trend = 0.15)). However, sex (p-interaction = 0.06) and body mass index (p-interaction < 0.01) modified the relation between plasma enterolactone and colorectal cancer risk; increased risks were observed among women and subjects with a high body mass index. The association between plasma enterodiol and colorectal cancer risk was modified by smoking status; risk was increased among current smokers (p-interaction < 0.01). These findings do not support the hypothesis that high plasma enterodiol or enterolactone concentrations are associated with reduced risk of colorectal cancer.

Relation between plasma enterodiol and enterolactone and dietary intake of lignans in a Dutch endoscopy-based population.

Enterolignans are phytoestrogenic compounds derived from the conversion of dietary lignans by the intestinal microflora that may be protective against cardiovascular diseases and cancer. To evaluate the use of enterolignans as biomarkers of dietary lignan intake, we studied the relation between plasma and dietary lignans. We determined the dietary intake of 4 lignans (secoisolariciresinol (SECO), matairesinol (MAT), pinoresinol, and lariciresinol) using the European Prospective Investigation into Cancer and Nutrition FFQ, and plasma enterodiol (END) and enterolactone (ENL) concentrations were determined by liquid chromatography-tandem mass spectrometry. The population consisted of 637 men and women, aged 19-75 y, participating in a case-control study on colorectal adenomas. Participants did not use antibiotics in the preceding calendar year. We found a modest association between lignan intake and plasma END (Spearman r = 0.09, P = 0.03) and ENL (Spearman r = 0.18, P <0.001). The correlation of total lignan intake with plasma enterolignans was slightly stronger than that of only SECO plus MAT. The plasma concentrations of both END and ENL were associated with intake of dietary fiber and vegetable protein but not with intake of other macronutrients. The relation between lignan intake and plasma END was modulated by age and previous use of antibiotics, whereas for ENL, it was modulated by weight, current smoking, and frequency of defecation. However, even when we included these nondietary factors in the regression models, the explained variance in plasma END and ENL remained low (2 and 13%, respectively).

Plasma enterolignans are associated with lower colorectal adenoma risk.

Lignans are biphenolic compounds that occur in foods of plant origin such as whole grains, seeds, fruits and vegetables, and beverages, such as coffee and tea. Plant lignans are converted by intestinal bacteria into the enterolignans, enterodiol and enterolactone. Enterolignans possess several biological activities, whereby they may influence carcinogenesis. We studied the associations between plasma enterolignans and the risk of colorectal adenomas in a Dutch case-control study. Colorectal adenomas are considered to be precursors of colorectal cancer. Cases (n = 532) with at least one histologically confirmed colorectal adenoma and controls (n = 503) with no history of any type of adenoma were included. Plasma enterodiol and enterolactone concentrations were measured by liquid chromatography with tandem mass spectrometry. Associations were stronger for incident than for prevalent cases. When only incident cases (n = 262) were included, high compared to low plasma concentrations of enterodiol were associated with a reduction in colorectal adenoma risk after adjustment for confounding variables. Enterodiol odds ratios (95% confidence intervals) were 1.00, 0.69 (0.42-1.13), 0.60 (0.37-0.99), and 0.53 (0.32-0.88) with a significant trend (P = 0.01) through the quartiles. Although enterolactone plasma concentrations were 10-fold higher, enterolactone's reduction in risk was not statistically significant (P for trend = 0.09). Use of oral antibiotic therapy could decrease the plasma concentrations of enterolactone. Exclusion of antibiotic users resulted in similar odds ratios for both enterolignans, but the association for enterolactone became somewhat stronger (P = 0.05 versus P = 0.09). We observed a substantial reduction in colorectal adenoma risk among subjects with high plasma concentrations of enterolignans, in particular, enterodiol. These findings could be important in the prevention of colorectal adenomas.

The relative bioavailability of enterolignans in humans is enhanced by milling and crushing of flaxseed.

Flaxseed is one of the richest sources of lignans and is increasingly used in food products or as a supplement. Plant lignans can be converted by intestinal bacteria into the so-called enterolignans, enterodiol and enterolactone. For a proper evaluation of potential health effects of enterolignans, information on their bioavailability is essential. The aim of this study was to investigate whether crushing and milling of flaxseed enhances the bioavailability of enterolignans in plasma. In a randomized, crossover study, 12 healthy subjects supplemented their diet with 0.3 g whole, crushed, or ground flaxseed/(kg body weight . d). Each subject consumed flaxseed for 10 successive days separated by 11-d run-in/wash-out periods, in which the subjects consumed a diet poor in lignans. Blood samples were collected at the end of each run-in/wash-out period, and at the end of each supplement period. Plasma enterodiol and enterolactone were measured using LC-MS-MS. The mean relative bioavailability of enterolignans from whole compared with ground flaxseed was 28% (P < or = 0.01), whereas that of crushed compared with ground flaxseed was 43% (P < or = 0.01). Crushing and milling of flaxseed substantially improve the bioavailability of the enterolignans.