Changes in Bone Marrow Fat upon Dietary-Induced Weight Loss.

BACKGROUND: Bone marrow fat is implicated in metabolism, bone health and haematological diseases. Thus, this study aims to analyse the impact of moderate weight loss on bone marrow fat content (BMFC) in obese, healthy individuals. METHODS: Data of the HELENA-Trial (Healthy nutrition and energy restriction as cancer prevention strategies: a randomized controlled intervention trial), a randomized controlled trial (RCT) among 137 non-smoking, overweight or obese participants, were analysed to quantify the Magnetic Resonance Imaging (MRI)-derived BMFC at baseline, after a 12-week dietary intervention phase, and after a 50-week follow-up. The study cohort was classified into quartiles based on changes in body weight between baseline and week 12. Changes in BMFC in respect of weight loss were analysed by linear mixed models. Spearman's coefficients were used to assess correlations between anthropometric parameters, blood biochemical markers, blood cells and BMFC. RESULTS: Relative changes in BMFC from baseline to week 12 were 0.0 ± 0.2%, -3.2 ± 0.1%, -6.1 ± 0.2% and -11.5 ± 0.6% for Q1 to Q4. Across all four quartiles and for the two-group comparison, Q1 versus Q4, there was a significant difference (p < 0.05) for changes in BMFC. BMFC was not associated with blood cell counts and showed only weaker correlations (<0.3) with metabolic biomarkers. CONCLUSION: Weight loss is associated with a decrease of BMFC. However, BMFC showed no stronger associations with inflammatory and metabolic biomarkers.

Changes in Plasma Short-Chain Fatty Acid Levels after Dietary Weight Loss Among Overweight and Obese Adults over 50 Weeks.

Gut microbial-derived short-chain fatty acids (SCFAs) may regulate energy homeostasis and exert anti-carcinogenic, immunomodulatory and anti-inflammatory effects. Smaller trials indicate that dietary weight loss may lead to decreased SCFA production, but findings have been inconclusive. SCFA concentrations were measured by HPLC-MS/MS in plasma samples of 150 overweight or obese adults in a trial initially designed to evaluate the metabolic effects of intermittent (ICR) versus continuous (CCR) calorie restriction (NCT02449148). For the present post hoc analyses, participants were classified by quartiles of weight loss, irrespective of the dietary intervention. Linear mixed models were used to analyze weight-loss-induced changes in SCFA concentrations after 12, 24 and 50 weeks. There were no differential changes in SCFA levels across the initial study arms (ICR versus CCR versus control) after 12 weeks, but acetate concentrations significantly decreased with overall weight loss (mean log-relative change of -0.7 ± 1.8 in the lowest quartile versus. -7.6 ± 2 in the highest, p = 0.026). Concentrations of propionate, butyrate and other SCFAs did not change throughout the study. Our results show that weight-loss, achieved through calorie restriction, may lead to smaller initial decreases in plasma acetate, while plasma SCFAs generally remain remarkably stable over time.

Generalizability of a Diabetes-Associated Country-Specific Exploratory Dietary Pattern Is Feasible Across European Populations.

BACKGROUND: Population-specificity of exploratory dietary patterns limits their generalizability in investigations with type 2 diabetes incidence. OBJECTIVE: The aim of this study was to derive country-specific exploratory dietary patterns, investigate their association with type 2 diabetes incidence, and replicate diabetes-associated dietary patterns in other countries. METHODS: Dietary intake data were used, assessed by country-specific questionnaires at baseline of 11,183 incident diabetes cases and 14,694 subcohort members (mean age 52.9 y) from 8 countries, nested within the European Prospective Investigation into Cancer and Nutrition study (mean follow-up time 6.9 y). Exploratory dietary patterns were derived by principal component analysis. HRs for incident type 2 diabetes were calculated by Prentice-weighted Cox proportional hazard regression models. Diabetes-associated dietary patterns were simplified or replicated to be applicable in other countries. A meta-analysis across all countries evaluated the generalizability of the diabetes-association. RESULTS: Two dietary patterns per country/UK-center, of which overall 3 dietary patterns were diabetes-associated, were identified. A risk-lowering French dietary pattern was not confirmed across other countries: pooled HRFrance per 1 SD: 1.00; 95% CI: 0.90, 1.10. Risk-increasing dietary patterns, derived in Spain and UK-Norfolk, were confirmed, but only the latter statistically significantly: HRSpain: 1.09; 95% CI: 0.97, 1.22 and HRUK-Norfolk: 1.12; 95% CI: 1.04, 1.20. Respectively, this dietary pattern was characterized by relatively high intakes of potatoes, processed meat, vegetable oils, sugar, cake and cookies, and tea. CONCLUSIONS: Only few country/center-specific dietary patterns (3 of 18) were statistically significantly associated with diabetes incidence in this multicountry European study population. One pattern, whose association with diabetes was confirmed across other countries, showed overlaps in the food groups potatoes and processed meat with identified diabetes-associated dietary patterns from other studies. The study demonstrates that replication of associations of exploratory patterns with health outcomes is feasible and a necessary step to overcome population-specificity in associations from such analyses.

Effects of Weight-Loss Interventions on Short-Chain Fatty Acid Concentrations in Blood and Feces of Adults: A Systematic Review.

Short-chain fatty acids (SCFAs, mainly acetate, propionate, and butyrate), which are primarily derived from the gut microbiome, may exert anti-inflammatory and immunomodulatory effects, and regulate energy homeostasis. It has been suggested that weight loss may affect SCFA metabolism, but a systematic review of intervention studies is lacking. We aimed to systematically assess the effects of dietary, physical activity-based, and surgical weight-loss interventions among overweight [body mass index (BMI) 25-29.9 kg/m2)] or obese (BMI ≥30 kg/m2) adults (≥18 y) on concentrations of acetate, propionate, butyrate, and total SCFAs in blood, urine, or feces. We conducted a systematic literature search in PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) up to April 30, 2018 for randomized and nonrandomized weight-loss trials among overweight or obese adults, in which the concentrations of individual and total SCFAs were assessed. A total of 9 studies consisting of 2 randomized parallel-arm trials, 4 crossover trials, and 3 nonrandomized clinical or surgical trials were included. In the majority of studies, changes in fecal SCFA concentrations were assessed, whereas changes in serum SCFAs were reported from 1 trial. Individual and total SCFA concentrations either remained unchanged or decreased significantly following weight loss. Three of the dietary interventions that resulted in decreased SCFA concentrations were low (≤5% of energy) in total carbohydrates. Most of the studies had a high risk of bias. Decreases in SCFA concentrations may accompany weight loss induced by bariatric surgery or dietary restriction among overweight or obese adults, particularly when carbohydrate intake is reduced. However, findings were inconsistent and based on studies with high to unclear risk of bias, and small sample sizes. Because measurements of fecal SCFAs may not be ideal due to limited sample standardization, well-powered trials with repeated blood measurements of SCFAs are required. This review was registered at PROSPERO as CRD42018088716.

Key Genes of Lipid Metabolism and WNT-Signaling Are Downregulated in Subcutaneous Adipose Tissue with Moderate Weight Loss.

Smaller cross-sectional studies and bariatric surgery trials suggest that weight loss may change the expression of genes in adipose tissue that have been implicated in the development of metabolic diseases, but well-powered intervention trials are lacking. In post hoc analyses of data from a 12-week dietary intervention trial initially designed to compare metabolic effects of intermittent vs. continuous calorie restriction, we analyzed the effects of overall weight loss on the subcutaneous adipose tissue (SAT) transcriptome. Changes in the transcriptome were measured by microarray using SAT samples of 138 overweight or obese individuals (age range: 35⁻65 years, BMI range: 25⁻40, non-smokers, non-diabetics). Participants were grouped post hoc according to the degree of their weight loss by quartiles (average weight loss in quartiles 1 to 4: 0%, -3.2%, -5.9%, and -10.7%). Candidate genes showing differential expression with weight loss according to microarray analyses were validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), and fold changes (FCs) were calculated to quantify differences in gene expression. A comparison of individuals in the highest vs. the lowest weight loss quartile revealed 681 genes to be differentially expressed (corrected p < 0.05), with 40 showing FCs of at least 0.4. Out of these, expression changes in secreted frizzled-related protein 2 (SFRP2, FC = 0.65, p = 0.006), stearoyl-CoA desaturase (SCD, FC = -1.00, p < 0.001), and hypoxia inducible lipid droplet-associated (HILPDA, FC = -0.45, p = 0.001) with weight loss were confirmed by RT-qPCR. Dietary weight loss induces significant changes in the expression of genes implicated in lipid metabolism (SCD and HILPDA) and WNT-signaling (SFRP2) in SAT.

Anthropometric and blood parameters for the prediction of NAFLD among overweight and obese adults.

BACKROUND: Non-alcoholic fatty liver disease (NAFLD) comprises non-progressive steatosis and non-alcoholic steatohepatitis (NASH), the latter of which may cause cirrhosis and hepatocellular carcinoma (HCC). As NAFLD detection is imperative for the prevention of its complications, we evaluated whether a combination of blood-based biomarkers and anthropometric parameters can be used to predict NAFLD among overweight and obese adults. METHODS: 143 overweight or obese non-smokers free of diabetes (50% women, age: 35-65 years) were recruited. Anthropometric indices and routine biomarkers of metabolism and liver function were measured to predict magnetic resonance (MR) - derived NAFLD by multivariable logistic regression models. In addition, we evaluated to which degree the use of more novel biomarkers (adiponectin, leptin, resistin, C-reactive protein, TNF-α, IL-6, IL-8 and interferon-γ) could improve prediction models. RESULTS: NAFLD was best predicted by a combination of age, sex, waist circumference, ALT, HbA1c, and HOMA-IR at an area under the receiver operating characteristic curve (AUROC) of 0.87 (95% CI: 0.81, 0.93) before and 0.85 (95% CI: 0.78, 0.91) after internal bootstrap validation. The use of additional biomarkers of inflammation and metabolism did not improve NAFLD prediction. Previously published indices predicted NAFLD at AUROCs between 0.71 and 0.82. CONCLUSIONS: The AUROC of > 0.8 obtained by our regression model suggests the feasibility of a non-invasive detection of NAFLD by anthropometry and circulating biomarkers, even though further increments in the capacity of prediction models may be needed before NAFLD indices can be applied in routine clinical practice.

Pre-diagnostic plasma concentrations of Fibrinogen, sGPIIb/IIIa, sP-selectin, sThrombomodulin, Thrombopoietin in relation to cancer risk: Findings from a large prospective study.

While enhanced platelet activation may drive cancer progression and metastases, less is known about its role in early cancer development. Thus, we evaluated whether pre-diagnostic biomarkers of platelet activation and coagulation are related to the risks of common cancers in the prospective EPIC-Heidelberg Study using a case-cohort design. Levels of fibrinogen, soluble glycoprotein (sGP) IIb/IIIa, soluble P-selectin (sP-selectin), soluble thrombomodulin (sTM), and thrombopoietin (TPO) were measured in baseline plasma samples of a random subcohort (n = 2,480) and incident cases of breast (n = 605), prostate (n = 543), and colorectal cancer (n = 249). Multivariable Cox regression models revealed no statistically significant associations between biomarker concentrations and any of the cancer endpoints. Subgroup analyses showed a significant inverse relationship between TPO and colorectal cancer among men, with a hazard ratio (HR, highest vs. lowest quartile) of 0.60 (95% confidence interval: 0.37,0.95), whereas no significant association was observed among women. With regard to fibrinogen levels and breast cancer risk, there was a significant positive association among nulliparous women (HR: 2.53 [95% CI: 1.21, 5.30]), but not among parous women. Overall, our data suggest that enhanced platelet activation and a pro-coagulative state may not be related to increased risks of common cancers, although studies on other potential biomarkers of platelet activation and further cancer types are needed. Findings from our subgroup analyses require further investigation, as potential underlying mechanisms are not known.

Inflammatory potential of the diet and risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

Background: Chronic inflammation plays a critical role in the pathogenesis of the 2 major types of gastric cancer. Several foods, nutrients, and nonnutrient food components seem to be involved in the regulation of chronic inflammation. Objective: We assessed the association between the inflammatory potential of the diet and the risk of gastric carcinoma, overall and for the 2 major subsites: cardia cancers and noncardia cancers. Design: A total of 476,160 subjects (30% men, 70% women) from the European Investigation into Cancer and Nutrition (EPIC) study were followed for 14 y, during which 913 incident cases of gastric carcinoma were identified, including 236 located in the cardia, 341 in the distal part of the stomach (noncardia), and 336 with overlapping or unknown tumor site. The dietary inflammatory potential was assessed by means of an inflammatory score of the diet (ISD), calculated with the use of 28 dietary components and their corresponding inflammatory scores. The association between the ISD and gastric cancer risk was estimated by HRs and 95% CIs calculated by multivariate Cox regression models adjusted for confounders. Results: The inflammatory potential of the diet was associated with an increased risk of gastric cancer. The HR (95% CI) for each increase in 1 SD of the ISD were 1.25 (1.12, 1.39) for all gastric cancers, 1.30 (1.06, 1.59) for cardia cancers, and 1.07 (0.89, 1.28) for noncardia cancers. The corresponding values for the highest compared with the lowest quartiles of the ISD were 1.66 (1.26, 2.20), 1.94 (1.14, 3.30), and 1.07 (0.70, 1.70), respectively. Conclusions: Our results suggest that low-grade chronic inflammation induced by the diet may be associated with gastric cancer risk. This pattern seems to be more consistent for gastric carcinomas located in the cardia than for those located in the distal stomach. This study is listed on the ISRCTN registry as ISRCTN12136108.

Iron status in relation to cancer risk and mortality: Findings from a population-based prospective study.

While experimental evidence suggests potential carcinogenic effects of increased iron load, there is a lack of data on iron status and cancer risk from epidemiological studies. Here, we evaluated prediagnostic serum concentrations of ferritin, iron and transferrin as well as transferrin saturation (TSAT) in relation to cancer risk and mortality in a prospective study by multivariable Cox regression analyses. A case-cohort sample of the population-based EPIC-Heidelberg Study including a random subcohort (n = 2738) and incident cases of breast cancer (n = 627), prostate cancer (n = 554), lung cancer (n = 195), colorectal cancer (n = 256) and cancer death (n = 759) was used. Ferritin levels were inversely associated with breast cancer risk in the multivariable Cox regression model, with a hazard ratio (HR) of 0.67 [95% confidence interval: 0.49, 0.92] for women in the highest quartile compared to those in the lowest quartile. Neither ferritin nor the other markers of iron status were significantly associated with colorectal, prostate or lung cancer risk. An inverse association was observed between ferritin and total cancer mortality (HR: 0.70 [0.53, 0.92]). There were no significant overall associations between serum iron, transferrin or TSAT and cancer mortality. The present findings do not support the notion of increased iron load constituting a cancer risk factor in the general population. By contrast, our analyses revealed inverse associations between ferritin levels and breast cancer risk as well as cancer mortality.

Red meat consumption and risk of cardiovascular diseases-is increased iron load a possible link?

Background: High iron load and red meat consumption could increase the risk of cardiovascular diseases (CVDs). As red meat is the main source of heme iron, which is in turn a major determinant of increased iron load, adverse cardiometabolic effects of meat consumption could be mediated by increased iron load. Objective: The object of the study was to assess whether associations between red meat consumption and CVD risk are mediated by iron load in a population-based human study. Design: We evaluated relations between red meat consumption, iron load (plasma ferritin), and risk of CVD in the prospective EPIC-Heidelberg Study using a case-cohort sample including a random subcohort (n = 2738) and incident cases of myocardial infarction (MI, n = 555), stroke (n = 513), and CVD mortality (n = 381). Following a 4-step mediation analysis, associations between red meat consumption and iron load, red meat consumption and CVD risk, and iron load and CVD risk were assessed by multivariable regression models before finally testing to which degree associations between red meat consumption and CVD risk were attenuated by adjustment for iron status. Results: Red meat consumption was significantly positively associated with ferritin concentrations and MI risk [HR per 50 g daily intake: 1.18 (95% CI: 1.05, 1.33)], but no significant associations with stroke risk and CVD mortality were observed. While direct associations between ferritin concentrations and MI risk as well as CVD mortality were significant in age- and sex-adjusted Cox regression models, these associations were substantially attenuated and no longer significant after multivariable adjustment for classical CVD risk factors. Strikingly, ferritin concentrations were positively associated with a majority of classical CVD risk factors (age, male sex, alcohol intake, obesity, inflammation, and lower education). Conclusion: Increased ferritin concentrations may be a marker of an overall unfavorable risk factor profile rather than a mediator of greater CVD risk due to meat consumption.

Albumin, bilirubin, uric acid and cancer risk: results from a prospective population-based study.

BACKGROUND: It has long been proposed that albumin, bilirubin and uric acid may inhibit cancer development due to their anti-oxidative properties. However, there is a lack of population-based studies on blood levels of these molecules and cancer risk. METHODS: Associations between pre-diagnostic serum albumin, bilirubin and uric acid and the risks of common cancers as well as cancer death in the EPIC-Heidelberg cohort were evaluated by multivariable Cox regression analyses. A case-cohort sample including a random subcohort (n=2739) and all incident cases of breast (n=627), prostate (n=554), colorectal (n=256), and lung cancer (n=195) as well as cancer death (n=761) that occurred between baseline (1994-1998) and 2009 was used. RESULTS: Albumin levels were inversely associated with breast cancer risk (hazard ratioQuartile 4 vs Quartile 1 (95% CI): 0.71 (0.51, 0.99), Plinear trend=0.004) and overall cancer mortality (HRQ4 vs Q1 (95% CI): 0.64 (0.48, 0.86), Plinear trend<0.001) after multivariable adjustment. Uric acid levels were also inversely associated with breast cancer risk (HRQ4 vs Q1 (95% CI): 0.72 (0.53, 0.99), Plinear trend=0.043) and cancer mortality (HRQ4 vs Q1 (95% CI): 0.75 (0.58, 0.98), Plinear trend=0.09). There were no significant associations between albumin or uric acid and prostate, lung and colorectal cancer. Serum bilirubin was not associated with any cancer end point. CONCLUSIONS: The present findings indicate that higher levels of albumin and uric acid are related to lower risks of breast cancer and cancer mortality. Further studies are needed to assess whether the observed associations are causal.

Identification of Urinary Polyphenol Metabolite Patterns Associated with Polyphenol-Rich Food Intake in Adults from Four European Countries.

We identified urinary polyphenol metabolite patterns by a novel algorithm that combines dimension reduction and variable selection methods to explain polyphenol-rich food intake, and compared their respective performance with that of single biomarkers in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The study included 475 adults from four European countries (Germany, France, Italy, and Greece). Dietary intakes were assessed with 24-h dietary recalls (24-HDR) and dietary questionnaires (DQ). Thirty-four polyphenols were measured by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS-MS) in 24-h urine. Reduced rank regression-based variable importance in projection (RRR-VIP) and least absolute shrinkage and selection operator (LASSO) methods were used to select polyphenol metabolites. Reduced rank regression (RRR) was then used to identify patterns in these metabolites, maximizing the explained variability in intake of pre-selected polyphenol-rich foods. The performance of RRR models was evaluated using internal cross-validation to control for over-optimistic findings from over-fitting. High performance was observed for explaining recent intake (24-HDR) of red wine (r = 0.65; AUC = 89.1%), coffee (r = 0.51; AUC = 89.1%), and olives (r = 0.35; AUC = 82.2%). These metabolite patterns performed better or equally well compared to single polyphenol biomarkers. Neither metabolite patterns nor single biomarkers performed well in explaining habitual intake (as reported in the DQ) of polyphenol-rich foods. This proposed strategy of biomarker pattern identification has the potential of expanding the currently still limited list of available dietary intake biomarkers.

Biological reproducibility of circulating P-Selectin, Thrombopoietin, GPIIb/IIIa and Thrombomodulin over one year.

BACKGROUND: Enhanced platelet activation has been implicated in several pathophysiological processes. Here, we evaluated the biological reproducibility of circulating P-Selectin, Thrombomodulin (TM), Thrombopoietin (TPO), and Glycoprotein IIb/IIIa (GPIIb/IIIa) to assess whether these analytes can be used as reliable biomarkers of platelet activation in epidemiological studies. METHODS: We measured circulating P-Selectin, TM, TPO and GPIIb/IIIa by immunoassays in two blood samples of 78 participants of the EPIC Heidelberg study (47-80years, 50% female) that were collected one year apart. Biological reproducibility of biomarker levels over time and associations with routine biochemistry parameters were assessed by Spearman's correlation coefficients. RESULTS: Statistical analyses revealed good reproducibility over one year for two of the analyzed markers, with Spearman coefficients of ρ=0.80 (P-Selectin) and ρ=0.73 (TPO) and reasonable reproducibility for TM (ρ=0.63) and GPIIb/IIIa (ρ=0.51). Levels of P-Selectin, TM, TPO and GPIIb/IIIa were not significantly associated with routine biochemistry parameters, such as glucose, HbA1c, LDL, HDL, Triglycerides and CRP. CONCLUSIONS: Our findings suggest that a single assessment of P-Selectin, TM, TPO and GPIIb/IIIa at baseline in prospective epidemiological studies is appropriate to investigate associations between platelet activation and risks of chronic diseases.

Dietary essential α-linolenic acid and linoleic acid differentially modulate TNFα-induced NFκB activity in FADS2-deficient HEK-293 cells.

The pro- or anti-inflammatory bioactivity of dietary essential linoleic acid (LA) and alpha-linolenic acid (ALA) is mainly attributed to rate-limiting delta-6 desaturase (D6D) activity. The aim of this study was to analyze mechanisms of D6D-substrates ALA, LA and D6D-product gamma-linolenic acid (GLA) under D6D-deficient conditions. Fatty acid profiles (GC-MS), D6D gene expression (real-time RT-PCR) and NFκB activity (luciferase assay) were assessed in HEK293 cells. FADS2 gene expression was approved being marginal. Incubation with ALA or LA did not increase D6D products but their elongase products C20:3n-3 and C20:2n-6. Bypassing the D6D, GLA elevated C20:3n-6 and C20:4n-6. LA significantly increased (+18% at 60 µM; p < .001), ALA reduced (-32% at 100 µM; p < .001) and GLA did not specifically change NFκB activity. Our data indicate that D6D might not be essential for the distinct effects of LA and ALA on NFκB activity.

The effects of intermittent calorie restriction on metabolic health: Rationale and study design of the HELENA Trial.

Mechanistic studies suggest benefits of intermittent calorie restriction (ICR) in chronic disease prevention that may exceed those of continuous calorie restriction (CCR), even at equal net calorie intake. Despite promising results from first trials, it remains largely unknown whether ICR-induced metabolic alterations reported from experimental studies can also be observed in humans, and whether ICR diets are practicable and effective in real life situations. Thus, we initiated the HELENA Trial to test the effects of ICR (eu-caloric diet on five days and very low energy intake on two days per week) on metabolic parameters and body composition over one year. We will assess the effectiveness of ICR compared to CCR and a control diet over a 12-week intervention, 12-week maintenance phase and 24-week follow-up in 150 overweight or obese non-smoking adults (50 per group, 50% women). Our primary endpoint is the difference between ICR and CCR with respect to fold-changes in expression levels of 82 candidate genes in abdominal subcutaneous adipose tissue biopsies (SATb) during the intervention phase. The candidate genes represent pathways, which may link obesity-related metabolic alterations with the risk for major chronic diseases. In secondary and exploratory analyses, changes in metabolic, hormonal, inflammatory and metagenomic parameters measured in different biospecimens (SATb, blood, urine, stool) are investigated and effects of ICR/CCR/control on imaging-based measures of subcutaneous, visceral and hepatic fat are evaluated. Our study is the first randomized trial over one year testing the effects of ICR on metabolism, body composition and psychosocial factors in humans.