The aim of this study was to investigate the association between polymorphisms in folic acid metabolism-related genes and idiopathic recurrent early pregnancy loss (REPL). A prospective case–control study was performed on a cohort of 82 REPL patients and 166 healthy controls. Genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C was assessed by applying polymerase chain reaction for amplification followed by DNA sequencing, for methionine synthase reductase A66G, solute carrier family 19, member 1 (SLC19A1) G80A and C696T, and genotyping was done by utilizing the Sequenom MassARRAY system. The results revealed a significant association between MTHFR A1298C polymorphism and idiopathic REPL. Haplotype analysis indicated that the MTHFR 677C-MTHFR 1298C allele combination was associated with REPL (P < 0.001). The MTHFR 677C-MTHFR 1298A and SLC19A1 80G-SLC19A1 696C allele combinations had lower frequencies in patients with REPL, but with P > 0.05 (P = 0.093 and P = 0.084, respectively).
MTHFR; MTRR; SLC19A1; Polymorphism; Homocysteine; Folic acid
Long-chain n-3 fatty acids (n-3 LCPUFA) improve blood pressure (BP) and lipid profile in adults and improve insulin sensitivity in rodents. We have previously shown that n-3 LCPUFA reduces BP and plasma triacylglycerol (TAG) in infants. Few studies have found effects on glucose homeostasis in humans. We explored possible effect modification by FADS, PPARG2, and COX2 genotypes to support potential effects of n-3 LCPUFA on metabolic markers in infants. Danish infants (133) were randomly allocated to daily supplementation with a teaspoon (~5 mL/day) of fish oil (FO) or sunflower oil (SO) from 9 to 18 months of age. Before and after the intervention, we assessed BP, erythrocyte n-3 LCPUFA, plasma lipid profile, insulin, and glucose in addition to functional single nucleotide polymorphisms in FADS, PPARG2, and COX2. At 18 months, plasma TAG was lower in the FO compared with SO group (p = 0.014). This effect was modified by PPARG2-Pro12Ala, as TAG only decreased among heterozygotes. FO supplemented PPARG2 Pro12Ala heterozygotes also had decreased plasma glucose compared with the SO group (p = 0.043). The effect of FO on mean arterial BP at 18 months was gender dependent (p = 0.020) and reduced in boys only (p = 0.028). Diastolic BP was, however, lower among all FO supplemented homozygous COX2-T8473C variant allele carriers compared with the SO group (p = 0.001). In conclusion, our results confirm that FO supplementation in late infancy reduces TAG and BP and indicates that the effects are mediated via peroxisome proliferator-activated receptor-γ and cyclooxygenase-2. Furthermore, FO reduced plasma glucose only in PPARG2 heterozygotes.
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Long-chain n-3 polyunsaturated fatty acids; Blood pressure; Lipid profile; Insulin; Glucose; Diet–gene interaction
From an epistemological point of view, nutritional physiology has been developed, like other factual sciences such as physics, from a purely descriptive to a mechanismic-explanatory scientific discipline. Nowadays, nutritional physiology has entered the molecular stage. Based on this micro-reductionism, molecular targets (e.g., transcription factors) of energy intake, certain nutrients (e.g., zinc) and selected plant bioactives (e.g., flavonoids) have been identified. Although these results are impressive, molecular approaches in nutritional physiology are limited by nature since the molecular targets of nutrients seem to have no ontic priority to understand the nutritional phenotype of an organism. Here we define, to the best of our knowledge, for the first time Nutri-informatics as a new bioinformatics discipline integrating large-scale data sets from nutritional studies into a stringent nutritional systems biology context. We suggest that Nutri-informatics, as an emerging field, may bridge the gap between nutritional biochemistry, nutritional physiology and metabolism to understand the interactions between an organism and its environment.
Micro-reductionism; Nutrigenomics; Nutritional systems biology; Nutri-informatics
Epidemiologic findings offer the promise that coffee or its many constituents may be useful as a dietary intervention in type 2 diabetes (T2D) prevention. We aimed to elucidate the molecular mechanisms involved in the ameliorative effects of caffeinated coffee (CC), decaffeinated coffee (DC) and unroasted caffeinated green coffee (GC) on skeletal muscle gene expression profiles and their relationships in an obesity animal model. Eight-week-old male C57BL6 mice were raised for 9 weeks ad libitum on a normal diet, a high-fat diet, or high-fat diet containing 2 % freeze-dried CC, or DC, or GC. Total RNA and protein were extracted from skeletal muscle and subjected to microarray (Mouse Genome 430 2.0, Affymetrix) and western blotting analyses, respectively. Coffee intake mitigated the insulin resistance by decreasing plasma glucose levels during an insulin tolerance test and by increasing tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), p85/IRS-1 complex and pAkt/PKB (protein kinase B). In addition, coffee intake down-regulated the anti-inflammatory genes activating transcription factor 3, FBJ osteosarcoma oncogene, heat shock protein 1A, heat shock protein 1B and synuclein, gamma and the inflammation-associated insulin signaling genes stearoyl-coenzyme A desaturase 1 and secreted phosphoprotein 1. These results provide scientific insight on the probable positive effects of coffee intake on impaired insulin signaling, inflammation and obesity, thereby providing a new perspective on the prevention of obesity and T2D.
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Coffee intake; Insulin resistance; Inflammation and obesity; Skeletal muscle; Transcriptomic analysis; High-fat diet
Curcumin from Curcuma longa may exert putative neuroprotective properties in the brain. Impaired mitochondrial function is implicated in Alzheimer’s disease and the presence of the apolipoprotein (APO) E4 genotype, which is a risk factor for late-onset Alzheimer’s disease, may aggravate mitochondrial malfunction. Here, we report that in the brain of 16-month-old APOE4-targeted replacement mice, adenosine triphosphate (ATP) concentrations were significantly lower than in APOE3 mice. A 3-month dietary supplementation of 0.2 % curcumin numerically increased ATP concentrations in APOE3 and significantly in APOE4 mice compared to the respective controls. Curcumin significantly induced the transcription of peroxisome proliferator-activated receptor (PPAR) γ and mitochondrial transcription factor A (TFAM) in APOE3, but not in APOE4 mice. Moreover, PPARγ coactivator (PGC)-1α and guanine–adenine repeat binding protein α (GABPa) mRNA was only increased in APOE3 mice. Consistent with these observations, protein expression of mitochondrial respiratory complexes, especially of complex IV, also appeared to be increased in APOE3 mice. In conclusion, we provide evidence that curcumin affects mitochondrial function and gene and protein expression in the murine brain despite its low bioavailability and carriers of the Alzheimer’s disease-risk genotype APOE4 may be less responsive to dietary curcumin than APOE3 carriers.
Curcumin; APOE; Mitochondrial function; ATP synthesis; Mice
The traditional Mediterranean diet (MedDiet) has shown beneficial effects on cognitive decline. Nevertheless, diet–gene interactions have been poorly evaluated. We aimed to investigate diet–gene interaction in the PREDIMED-NAVARRA randomized trial. A total of 522 participants (67 ± 6 years at baseline) enrolled in the PREDIMED-NAVARRA trial were randomly allocated to one of three diets: two MedDiets (supplemented with either extra-virgin olive oil or nuts) or a low-fat diet. They were evaluated with the Mini-Mental State Examination (MMSE) and the Clock Drawing Test (CDT) after 6.5 years of intervention. Subjects were genotyped for CR1-rs3818361, CLU-rs11136000, PICALM-rs3851179 and Apolipoprotein E (ApoE) genes. We studied MedDiet–gene interactions for cognition and assessed the effect of the MedDiet on cognition across different genetic profiles. A significant interaction (p = 0.041) between CLU-rs11136000 and the MedDiet intervention on the MMSE was found with a beneficial effect of MedDiet among carriers of the T minor allele (B = 0.97, 95 % CI 0.45–1.49). Similar effect was observed for CR1-rs3818361, but no significant interaction was observed (p = 0.335). For PICALM-rs3851179, the MedDiet intervention showed a beneficial effect in both genotype groups. No apparent interaction was found for the CDT between intervention and gene variants. Similarly, participants randomly allocated to MedDiet groups, with favorable profiles of CR1, CLU and PICALM genes, significantly improved CDT scores compared to controls with the same genetic profile. Cognitive performance was better for non-ApoE4 and for ApoE4 carriers of MedDiet groups compared to controls, but for CDT performance, we only found statistical significant differences for non-ApoE4 carriers. A MedDiet intervention modulates the effect of genetic factors on cognition. The effect of MedDiet might be greater for subjects with a more favorable genetic profile.
Mediterranean diet; Cognition; CLU; CR1; PICALM; APOE
The relative expression of mucin, pro- and anti-inflammatory genes besides other signaling molecules in HT-29 cells by two test probiotic strains of Lactobacillus plantarum Lp9 and Lp91 and the reference strain L. plantarum 5276 was evaluated by RT-qPCR using Relative Expression Software Tool qBase-Plus under in vitro simulated gut conditions. Ten house keeping genes were evaluated by using geNorm 3.4 excel based application. The most stable genes were RPL27, ACTB and B2M which were subsequently used for calculating the normalization factor. Under pretreatment conditions (4 h probiotic treatment, followed by lipopolysaccharide challenge for 3 h), all the three strains evoked downregulation of IL-8 expression by ~100 %, while in case of TNF-α, the downregulation of the relative gene expression was at the rate of 98.2, 93.8 and 98.0 % with Lp5276, Lp9 and Lp91, respectively, under the same set of conditions. Lp91 evoked maximum downregulation of IL12p35 and IFN-γ with corresponding fold reduction in relative expression of the two genes by 96.5 and 96.7 % during pre-treatment conditions. However, IL-10 and IFN-α were significantly upregulated to the extent of 8.13 ± 0.36 and 2.62 ± 0.14 fold by Lp91 under the same conditions. Lp9 and Lp91 were also quite effective in inducing the expression of Cox-1 and Cox-2 in HT-29 cells as can be reflected from their ratios, i.e., 5.90 and 6.50 (under pretreatment conditions); 3.79 and 4.36 (under co-culture conditions). Thus, the two putative indigenous L. plantarum strains Lp9 and Lp91 demonstrated immunomodulating functions in HT-29 cells at significant levels under different experimental conditions.
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Lactobacilli; Gene expression; HT-29; Lipopolysaccharide; Cytokines; Mucin
A large inter-individual variability in the plasma triglyceride (TG) response to fish oil consumption has been observed. The objective was to investigate the gene–diet interaction effects between single-nucleotide polymorphisms (SNPs) within glucokinase (GCK) gene and dietary carbohydrate intakes (CHO) on the plasma TG response to a fish oil supplementation. Two hundred and eight participants were recruited in the greater Quebec City area. The participants completed a 6-week fish oil supplementation (5 g fish oil/day: 1.9–2.2 g EPA and 1.1 g DHA). Thirteen SNPs within GCK gene were genotyped using TAQMAN methodology. A gene–diet interaction effect on the plasma TG response was observed with rs741038 and CHO adjusted for age, sex and BMI (p = 0.008). In order to compare the plasma TG response between genotypes according to CHO, participants were divided according to median CHO. Homozygotes of the minor C allele of rs741038 with high CHO >48.59 % had a greater decrease in their plasma TG concentrations following the intake of fish oil (p < 0.05) than C/C homozygotes with low CHO and also than the other genotypes either with high or low CHO. The plasma TG response to a fish oil supplementation may be modulated by gene–diet interaction effects involving GCK gene and CHO.
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Glucokinase; Carbohydrate; Fish oil; Triglyceride; Gene–diet interaction
Restriction of a high-fat diet (HFD) and a change to a low-fat diet (LFD) are two interventions that were shown to promote weight loss and improve parameters of metabolic health in obesity. Examination of the biochemical and molecular responses of white adipose tissue (WAT) to these interventions has not been performed so far. Here, male C57BL/6JOlaHsd mice, harboring an intact nicotinamide nucleotide transhydrogenase gene, were fed a purified 40 energy% HFD for 14 weeks to induce obesity. Afterward, mice were divided into three dietary groups: HFD (maintained on HFD), LFD (changed to LFD with identical ingredients), and HFD-CR (restricted to 70 % of the HFD). The effects of the interventions were examined after 5 weeks. Beneficial effects were seen for both HFD-CR and LFD (compared to HFD) regarding physiological parameters (body weight and fat mass) and metabolic parameters, including circulating insulin and leptin levels. Macrophage infiltration in WAT was reduced by both interventions, although more effectively by HFD-CR. Strikingly, molecular parameters in WAT differed between HFD-CR and LFD, with increased activation of mitochondrial carbohydrate and fat metabolism in HFD-CR mice. Our results confirm that restriction of the amount of dietary intake and reduction in the dietary energy content are both effective in inducing weight loss. The larger decrease in WAT inflammation and increase in mitochondrial carbohydrate metabolism may be due to a larger degree of energy restriction in HFD-CR, but could also be due to superior effectiveness of dietary restriction in weight loss strategies.
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Caloric restriction; Fat restriction; Nutrition; Metabolic health; White adipose tissue
The demand for diet products is continuously increasing, together with that for natural food ingredients. Stevioside and other steviol glycosides extracted from the leaves of the plant Stevia rebaudiana Bertoni are the first natural high-potency sweeteners to be approved for consumption in the United States and the European Union. However, the sweetness of these compounds is generally accompanied by aversive sensations, such as bitter and off-tastes, which may constitute a limit to their consumption. Moreover, consumers’ differences in sensitivity to high-potency sweeteners are well known, as well as difficulties in characterizing their aftertaste. Recently, TAS2R4 and TAS2R14 have been identified as the receptors that mediate the bitter off-taste of steviol glycosides in vitro. In the present study, we demonstrate that TAS2R4 gene polymorphism rs2234001 and TAS2R14 gene polymorphism rs3741843 are functional for stevioside bitterness perception.
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Stevioside; Bitter aftertaste; Genetic polymorphisms; hTAS2R4; hTAS2R14; hTAS2R38
Micronutrient research typically focuses on analyzing the effects of single or a few nutrients on health by analyzing a limited number of biomarkers. The observational study described here analyzed micronutrients, plasma proteins, dietary intakes, and genotype using a systems approach. Participants attended a community-based summer day program for 6–14 year old in 2 years. Genetic makeup, blood metabolite and protein levels, and dietary differences were measured in each individual. Twenty-four-hour dietary intakes, eight micronutrients (vitamins A, D, E, thiamin, folic acid, riboflavin, pyridoxal, and pyridoxine) and 3 one-carbon metabolites [homocysteine (Hcy), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH)], and 1,129 plasma proteins were analyzed as a function of diet at metabolite level, plasma protein level, age, and sex. Cluster analysis identified two groups differing in SAM/SAH and differing in dietary intake patterns indicating that SAM/SAH was a potential marker of nutritional status. The approach used to analyze genetic association with the SAM/SAH metabolites is called middle-out: SNPs in 275 genes involved in the one-carbon pathway (folate, pyridoxal/pyridoxine, thiamin) or were correlated with SAM/SAH (vitamin A, E, Hcy) were analyzed instead of the entire 1M SNP data set. This procedure identified 46 SNPs in 25 genes associated with SAM/SAH demonstrating a genetic contribution to the methylation potential. Individual plasma metabolites correlated with 99 plasma proteins. Fourteen proteins correlated with body mass index, 49 with group age, and 30 with sex. The analytical strategy described here identified subgroups for targeted nutritional interventions.
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Systems nutrition; Methylation potential; SAM/SAH; Micronutrients; Community-based participatory research
Flavonoids, a family of polyphenols, generally found in various fruits and vegetables, as well as in many plant beverages such as tea, pomegranate juice, raspberry, blueberries, and red wine. Recently, studies on flavonoids have attracted scientific attention as a potential nutritional strategy to prevent a broad range of chronic disorders. Many studies suggest that consumption of these flavonoids in sufficient amount plays neuroprotective, cardioprotective, anti-inflammatory, and chemopreventive roles. While there has been a major focus on the antioxidant properties, there is an emerging view that flavonoids and their in vivo metabolites do not act only as conventional antioxidants but may also exert modulatory actions on cellular system through direct action on various signalling pathways. These pathways include phosphoinositide 3-kinase, Akt/protein kinase B, mitogen-activated protein kinase, tyrosine kinases, and protein kinase C. Various inhibitory or stimulatory actions of flavonoids on these pathways greatly affect cellular functions by altering the phosphorylation state of targeted molecules. In addition, flavonoids also modulate various gene expressions through activation of various transcription factors. Thus, the present review will bestow a breathing overview regarding the prime role of flavonoids in modulation of survival signalling pathways at cellular system.
Plant polyphenols; Phosphoinositide 3-kinase; Akt/protein kinase B; Mitogen-activated protein kinase; Protein kinase C; Cell survival
Evidence relating dietary patterns to obesity and related disorders such as non-alcoholic fatty liver disease (NAFLD) is limited in pediatric age. Aim of this study was to analyze the association between dietary patterns, obesity and development of severe steatosis and the metabolic syndrome in a series of children and adolescents referred for suspected NAFLD, and the interaction with the rs738409 I148M PNPLA3 polymorphism. Two hundred patients (112 females) had completed a food frequency and demographic questionnaire. Nearly 58 % were obese, and 32 % were overweight. Mild, moderate, and severe fatty liver was present in 60 (30 %), 87 (44 %), and 51 (26 %) participants, respectively. A great proportion of overweight/obese children and adolescents reported a correct dietary pattern. At multivariate ordinal regression analysis considering demographic, anthropometric, genetic, and behavioral determinants, the major determinant of steatosis severity was PNPLA3 I148M genotype (p < 0.0001), followed by older age (p = 0.017), higher waist circumference (p = 0.016), and less time spent practising physical exercise (p = 0.034). Furthermore, there was a significant interaction between PNPLA3 I148M and intake of sweetened beverages (p = 0.033) and of vegetables (p = 0.038). In conclusion, although dietary pattern was reportedly correct in at-risk overweight adolescents with NAFLD, we report a novel interaction between PNPLA3 I148M and dietary components with the severity of steatosis.
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Food frequency; Dietary pattern; Non-alcoholic fatty liver disease; Obesity
Relatively rare variants with a moderate-to-high biological effect may contribute to the genetic predisposition of common disorders. To investigate this for obesity, we performed exome sequencing for 30 young (mean age: 29.7 years) extremely obese Caucasian subjects (mean body mass index: 51.1 kg/m2; m/f = 11/29). Rare variants with a moderate-to-high predicted biological effect were assembled and subjected to functional clustering analysis. It showed that the 55 clustered protocadherin genes on chromosome 5q31 have a significantly (P = 0.002) higher frequency of rare variants than a set of 325 reference genes. Since the protocadherin genes are expressed in the hypothalamus, we tested another 167 genes related to the function of the hypothalamus, but in those genes, the frequency of rare variants was not different from that of the reference genes. To verify the relation of variation in the protocadherin genes with extreme obesity, we analyzed data from more than 4,000 European Americans present on the Exome Variant Server, representing a sample of the general population. The significant enrichment of rare variants in the protocadherin genes was only observed with the group of extremely obese individuals but not in the “general population”, indicating an association between rare variants in the protocadherin cluster genes and extreme obesity.
Extreme obesity; Genetic variation; Functional clustering analysis; Protocadherins; Neuronal plasticity
In order to study the effects of vitamin C supplementation on gene expression and compare its action between physiological and inflammatory conditions, a pilot study was set up utilizing microarray and qPCR technologies. Five healthy volunteers were supplemented with 1 g vitamin C (Redoxon®) per day for five consecutive days. Peripheral blood mononuclear cells (PBMNC) were isolated before and just after the last supplementation, and RNA was isolated for the Affymetrix gene 1.0 ST chip analysis. PBMNC were also, ex vivo, treated with LPS, and gene expression was quantified by means of a “Human NFkB Signaling” qPCR array. Only a very moderate effect on the baseline gene expression modulation was associated with vitamin C supplementation. However, in spite of the limited number of subjects analyzed, vitamin C supplementation resulted in a markedly different modulation of gene expression upon the inflammatory stimulus, specifically at the level of the MyD88-dependent pathway and of the anti-inflammatory cytokine IL-10 synthesis. This study suggests that vitamin C supplementation in healthy subjects, not selected according to a specific genetic profile, consuming an adequate amount of vitamin C, and having a satisfactory vitamin C plasma concentration at the baseline, does not result in a significant modification of gene expression profile. Under this satisfactory micronutrient status, supplementation of vitamin C is “buffered” within a homeostatic physiological equilibrium. Differently, following a second “hit” constituted of an inflammatory stimulus such as LPS, able to trigger a critical burst to the normal physiological state, the higher availability of ascorbic acid emerges, and results in a significant modulation of cell response.
Cytokines; Gene expression; Inflammation; PBMNC; Vitamin C
Melanocortin 4 receptor (MC4R) has a major role in energy homeostasis. The rs17782313 polymorphism, mapped 188 kb downstream from MC4R, has been associated with satiety, higher body mass index (BMI) and total calorie intake in adults. To assess the association of rs17782313 with gastric functions, satiation, or satiety, we studied 178 predominantly Caucasian overweight and obese people: 120 females, 58 males; mean BMI 33.4 ± 5.3 kg/m2 (SD); age 37.7 ± 11.2 years. Quantitative traits assessed were gastric emptying (GE) of solids and liquids; fasting and postprandial gastric volume; satiation by maximum tolerated volume and 4 symptoms by 100-mm visual analog scales (VAS); and satiety by ad libitum buffet meal. Associations of genotype and quantitative traits were assessed by analysis of covariance (using gender and BMI as covariates), based on a dominant [TC (n = 72) − CC (n = 12) vs. TT (n = 94)] genetic model. rs17782313(C) was associated with postprandial satiation symptoms (median Δ total VAS 26.5 mm, p = 0.036), reduced proportion of solid GE at 2 h (median Δ 6.7 %, p = 0.008) and 4 h (median Δ 3.2 %, p = 0.006), and longer t½ (median Δ 6 min, p = 0.034). Associations of rs17782313 with obesity may be explained by reduced satiation and GE. The role of MC4R mechanisms in satiation and gastric function deserves further study.
Melanocortin 4 receptor (MC4R); rs17782313; Satiation; Gastric emptying; Obesity
We analysed single nucleotide polymorphisms (SNPs) tagging the genetic variability of six candidate genes (ATF6, FABP1, LPIN2, LPIN3, MLXIPL and MTTP) involved in the regulation of hepatic lipid metabolism, an important regulatory site of energy balance for associations with body mass index (BMI) and changes in weight and waist circumference. We also investigated effect modification by sex and dietary intake. Data of 6,287 individuals participating in the European prospective investigation into cancer and nutrition were included in the analyses. Data on weight and waist circumference were followed up for 6.9 ± 2.5 years. Association of 69 tagSNPs with baseline BMI and annual changes in weight as well as waist circumference were investigated using linear regression analysis. Interactions with sex, GI and intake of carbohydrates, fat as well as saturated, monounsaturated and polyunsaturated fatty acids were examined by including multiplicative SNP-covariate terms into the regression model. Neither baseline BMI nor annual weight or waist circumference changes were significantly associated with variation in the selected genes in the entire study population after correction for multiple testing. One SNP (rs1164) in LPIN2 appeared to be significantly interacting with sex (p = 0.0003) and was associated with greater annual weight gain in men (56.8 ± 23.7 g/year per allele, p = 0.02) than in women (−25.5 ± 19.8 g/year per allele, p = 0.2). With respect to gene–nutrient interaction, we could not detect any significant interactions when accounting for multiple testing. Therefore, out of our six candidate genes, LPIN2 may be considered as a candidate for further studies.
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LPIN2; Obesity; Weight gain; Gene–diet interaction
There is an impressing body of evidence supporting the beneficial role of balanced nutrition in lowering the risk of dementia and its commonest form, Alzheimer’s disease. Nevertheless, and despite worldwide dementia epidemic, there is much unfounded skepticism and lack of information among physicians. As a result, the diagnosis of cognitive impairment occurs still far too late, at best symptomatic drugs keep being prescribed and patients and caregivers are left with little concrete support in the hands of the natural history of the disease. This review summarizes knowledge about the impact of nutrition as part of a healthy lifestyle and of micronutrients in particular on delaying and avoiding dementia onset.
Nutrition; Clinical trial; Antioxidant; Oxidative stress; Alzheimer’s disease; Mild cognitive impairment
The oxidative stress is a key issue in the etiology of non-alcoholic fatty liver disease (NAFLD). The aim of our study was to evaluate the effect of metabolic gene polymorphisms involved in the oxidative stress (GSTT1, GSTM1, SULT1A1, CYP2E1, and 1A1), lifestyle and nutrition aspects, and their interaction, on the risk of NAFLD. We enrolled 294 cases and 359 controls, and collected demographics, anthropometric, lifestyle, and nutrition data. A subgroup of NAFLD provided additional data on nutrients and on physical activity engagement. Each patient provided a blood sample for DNA extraction and genotyping. Clinical and laboratory data were collected from cases. Multivariable analysis shows a significant protective effect of age, gender, and moderate drinking habits on the risk of NAFLD, while an increased risk for greater consumption of fruit and grilled meat or fish. Significant interactions were reported between alcohol consumption, fruit intake, grilled meat and fish, and selected genetic variants. From the subgroup analysis, a moderate/high consumption of fat and/or grilled meat/fish, and a high consumption of white meat increase the risk of NAFLD. Engaging any physical activity at least 1 time/week halves the risk of NAFLD. Besides confirming the beneficial effect of moderate alcohol intake and regular physical activity, and the increased risk associated with high fruit and fat intake, for the first time, we report a detrimental effect of grilled food on NAFLD risk. An effect modification by selected gene variants increases the risk in combination with fruit and grilled food intake.
Non-alcoholic fatty liver disease; Metabolic genes; Polymorphism; Nutrition; Gene-environment interaction
Cytosolic lipid droplets are versatile, evolutionarily conserved organelles that are important for the storage and utilization of lipids in almost all cell types. To obtain insight into the physiological importance of lipid droplet size, we isolated and characterized a new S-adenosyl methionine synthetase 1 (SAMS-1)-deficient Caenorhabditis elegans mutant, which have enlarged lipid droplets throughout its life cycle. We found that the sams-1 mutant showed a markedly reduced body size and progeny number; impaired synthesis of phosphatidylcholine, a major membrane phospholipid; and elevated expression of key lipogenic genes, such as dgat-2, resulting in the accumulation of triacylglyceride in fewer, but larger, lipid droplets. The sams-1 mutant store more than 50 % (wild type: 10 %) of its intestinal fat in large lipid droplets, ≥10 μm3 in size. In response to starvation, SAMS-1 deficiency causes reduced depletion of a subset of lipid droplets located in the anterior intestine. Given the importance of liberation of fatty acids from lipid droplets, we propose that the physiological function of SAMS-1, a highly conserved enzyme involved in one-carbon metabolism, is the limitation of fat storage to ensure proper growth and reproduction.
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One-carbon metabolism; Lipid homeostasis; Lipid droplet; Forward mutagenesis; Nutrigenomics
Observational studies have consistently shown associations between mild deficiencies in folate and vitamin B12 with increased risk of a myriad of common diseases. These findings have invariably translated into null outcomes in intervention trials due in part to our ignorance of the specific genomic and environmental factors that underpin population variability in requirements to these B-vitamins. Although genome-wide association studies have shed initial light on the genetic architecture of variability in status of these vitamins, particularly vitamin B12, the causal mechanisms remain uncharacterised. A recent study by Grarup et al. (PLoS Genet 9(6):e1003530, 2013) used next-generation whole-genome sequencing to gain further insight into the genetic architecture of vitamin B12 and folate status in the general population. Their study represents the analysis of approximately ten times greater number of genetic variants and nearly four times the number of individuals compared to the largest previous GWAS study of these B-vitamins. In light of this, we purport that although the study may be viewed as the state of the art in the roadmap to personalised or precision nutrition, the lack of insight provided by the study serves as a cautionary reminder of the importance of study design, particularly when leveraging large-scale data, such as those from whole-genome sequences. We believe that the precedent set by such large-scale “proof of principle” type projects will wrongly enforce a negative outlook for nutrigenomics research and present alternative study designs, which although less opportunistic are far more likely to be informative and yield novel results.
Whole-genome sequencing; Nutrigenomics; Vitamin B12; Folic acid; Heritability
Monoamine oxidase A (MAOA) gene polymorphisms resulting in high and low transcription rates are associated with individual differences in reward efficacy and response inhibition. Iron deficiency (ID) is the most frequent single-nutrient deficiency worldwide, and prenatal ID has recently been shown to carry a risk for lower mental development scores in infants. In this study, a potential interaction of MAOA genotype and prenatal ID was studied in young male rhesus monkeys. Cognitive tasks, including problem solving, responsiveness to reward and attention, were used to characterize the potential interaction of these two fetal risks. ID was induced by feeding rhesus monkey dams an iron-deficient (10 ppm, ID) or an iron-sufficient (100 ppm, IS) diet during gestation (n = 10/group). Subgroups of the ID and IS diet offspring had low-MAOA or high-MAOA transcription rate polymorphisms. ID combined with low-MAOA genotype showed distinctive effects on reward preference and problem solving while ID in hi-MAOA juveniles modified response inhibition. Given the incidence of ID and MAOA polymorphisms in humans, this interaction could be a significant determinant of cognitive performance.
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Rhesus; Infant; Anemia; MAOA polymorphism; Learning; Reward; Attention
The Ile148Met (rs738409, G-allele) in the patatin-like phospholipase domain-containing protein 3 gene (PNPLA3) associates with liver fat content and may lead to loss-of-function (hydrolysis) or gain-of-function (CoA-dependent lysophosphatidic acid acyltransferase) defects. PNPLA3 is up-regulated by dietary carbohydrates, and interactions between rs738409 and carbohydrates, and sugar and ω6:ω3-polyunsaturated fatty acid (PUFA) ratio on hepatic fat accumulation have been reported. We examined interaction between rs738409 and overweight, and between rs738409 and dietary intakes (carbohydrates, sucrose and ω6:ω3-PUFA ratio), on fasting triglyceride levels. From the Malmo Diet and Cancer Study-Cardiovascular Cohort, 4,827 individuals without diabetes aged 58 ± 6 years, 2,346 with BMI ≤ 25 kg/m2 and 2,478 with BMI > 25 kg/m2, were included in cross-sectional analyses. Dietary data were collected by a modified diet history method. Overweight modified the association between rs738409 and fasting triglyceride levels (Pinteraction = 0.003). G-allele associated with lower triglycerides only among overweight individuals (P = 0.01). Nominally, significant interaction on triglyceride levels was observed between rs738409 and sucrose among normal-weight individuals (Pinteraction = 0.03). G-allele associated with lower triglycerides among overweight individuals in the lowest tertiles of carbohydrate and ω6:ω3-PUFA ratio (P = 0.04 and P = 0.001) and with higher triglycerides among normal-weight individuals in the highest tertile of sucrose (P = 0.001). We conclude that overweight and dietary sucrose may modify the association between rs738409 and fasting triglyceride levels.
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The online version of this article (doi:10.1007/s12263-014-0388-4) contains supplementary material, which is available to authorized users.
PNPLA3; Diet; Fasting triglycerides; NAFLD; Sucrose; Polyunsaturated fatty acids
Phytosterols have been widely studied for their cholesterol-lowering effect. Conjugated phytosterol forms have been found more active than free moieties. There are no reports about the sterol profile of black bean seed coats neither its effects on cholesterol metabolism. The aim of this research was to identify and quantify phytosterols from black bean seed coats and to determine their effects on cholesterol micellar solubility and on mRNA and key protein levels involved in lipid/cholesterol metabolism and cholesterol transport in primary rat hepatocytes. Free phytosterols, acylated steryl glycosides, and steryl glycosides were extracted from black bean seed coats. They were identified through HPLC–MS–TOF and quantified through HPLC equipped with UV–visible and evaporative light-scattering detectors. Free and conjugated phytosterols from the coats significantly increased the inhibitory effect of cholesterol micelle formation compared with stigmasterol, which was used as control (P < 0.05). In addition, phytosterols of black bean seed coat decreased lipogenesis by the downregulation of lipogenic proteins such as sterol regulatory element-binding protein 1 and fatty acid synthesis (FAS) in primary rat hepatocytes. Regarding β-oxidation, phytosterols upregulated the expression of carnitine palmitoyltransferase I and promoted the β-oxidation of long-chain fatty acids. Phytosterols inhibited cholesterol micellar solubility and reduced the activation of the liver X receptor, decreasing hepatic FAS and promoting hepatic β-oxidation of long-chain fatty acids.
Black bean; Cholesterol lowering; Phytosterol composition; Lipid metabolism; Lipogenesis; β-Oxidation
Oleuropein, the major phenolic compound found in olive leaves and oil, exerts antioxidant, anti-inflammatory and anti-atherogenic effects and suppresses the adipocyte differentiation in vitro. Herein, we characterized molecular mechanisms underlying the anti-adipogenic effects of oleuropein on 3T3-L1 cells and adipocytes derived from stromal-vascular fraction of dorsolumbar and gonadal fat dissected from mice. We found that oleuropein (>100 μM) decreased viability of preadipocytes proliferating in vitro and did not exerted any cytotoxic effects in post-confluent cells after induction of differentiation. Oleuropein (>100 μM) inhibited adipocyte differentiation, suppressed gene expression of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-/enhancer-binding protein α, sterol regulatory element-binding transcription factor 1c and fatty acid synthase. Furthermore, we tested ability of oleuropein to regulate of PPARγ-, PPARα- or PPARβ-/PPARδ-mediated β-lactamase expression in appropriate reporter gene assays. Oleuropein between 10 and 400 μM concentrations did not affect activity of PPARα or PPARβ/δ. Contrary, PPARγ activity, either basal or rosiglitazone activated, was inhibited by oleuropein. Our data suggest that oleuropein exerts anti-adipogenic effect through direct inhibition of PPARγ transcriptional activity.
Electronic supplementary material
The online version of this article (doi:10.1007/s12263-013-0376-0) contains supplementary material, which is available to authorized users.
Oleuropein; Adipogenesis; PPARγ; Olive oil and leaf extracts; Catalase