Meropi D. Kontogianni

Association of the +45T>G and +276G>T polymorphisms in the adiponectin gene with insulin resistance in nondiabetic Greek women

OBJECTIVE We explored potential associations of two single nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ; +45T>G, rs2241766 and +276G>T, rs1501299) with circulating total and high-molecular weight (HMW) adiponectin, insulin resistance (IR), and markers of obesity in a healthy Greek female population. DESIGN AND METHODS The two SNPs were genotyped in 349 women without diabetes (mean age: 47.0+/-12.1 years, mean body mass index: 28.9+/-5.6 kg/m(2)). Total and HMW adiponectin concentrations, body composition variables, IR parameters, and plasma lipid levels were determined. RESULTS In single SNP analysis adjusting for several potential confounders, SNP +276G>T was associated with higher fasting insulin levels (P=0.01) and higher homeostasis model assessment index for IR (HOMA-IR; P=0.009), and SNP +45T>G was associated with lower insulin levels and HOMA-IR (P=0.05 and P=0.07 respectively). No association with total or HMW adiponectin, plasma lipid levels, and body composition variables was observed; however, haplotype analysis revealed that subjects homozygous for the most common +45T/+276G haplotype had lower total adiponectin levels than did noncarriers of this haplotype (P=0.02). The observed differences in HOMA-IR were very significant among women with a higher body fat (BF) percentage (>or= the population median of 41%; all P<or=0.005), but not among leaner individuals (P for interactions 0.01-0.07), thus suggesting that ADIPOQ effects on insulin sensitivity may depend upon BF status. CONCLUSION Our data suggest a significant role of ADIPOQ variants at positions +45 and +276 in the development of IR in healthy Greek women possibly through an interaction with BF.

Mediterranean Diet and Diabetes: Prevention and Treatment

The aim of the present review is to examine current scientific knowledge on the association between the Mediterranean diet and diabetes mellitus (mostly type 2 diabetes). A definition of the Mediterranean diet and the tools widely used to evaluate adherence to this traditional diet (Mediterranean diet indices) are briefly presented. The review focuses on epidemiological data linking adherence to the Mediterranean diet with the risk of diabetes development, as well as evidence from interventional studies assessing the effect of the Mediterranean diet on diabetes control and the management of diabetes-related complications. The above mentioned data are explored on the basis of evaluating the Mediterranean diet as a whole dietary pattern, rather than focusing on the effect of its individual components. Possible protective mechanisms of the Mediterranean diet against diabetes are also briefly discussed.

Flaxseed oil does not affect inflammatory markers and lipid profile compared to olive oil, in young, healthy, normal weight adults

OBJECTIVE Olive oil (OO) is a rich source of monounsaturated fat and bioactive components that exert strong anti-oxidant and anti-inflammatory properties. Flaxseed oil (FO) is rich in α-linolenic n-3 fatty acid (ALA), which also exhibits anti-inflammatory effects. This randomized, cross-over study aimed at exploring whether diets enrichment with FO could beneficially alter inflammatory markers and lipid profile, compared to OO, in a sample of normal weight, apparently healthy young adults. MATERIALS AND METHODS Participants were supplied with 15 mL/day of either FO or OO. Each intervention and the wash-out period lasted 6 weeks. Dietary, anthropometric and physical activity variables were recorded at the beginning and the end of each intervention. Serum biochemical and inflammatory markers were measured. Compliance to the intervention was evaluated by fatty acid analysis in erythrocytes. Repeated Measures ANOVA was used to assess the effect of the treatment. RESULTS Thirty seven participants completed the study. No difference between the two interventions was observed in adiponectin, TNF-α, high sensitivity-CRP or glucose levels and lipid profile. At the end of the FO period, participants exhibited significant reductions in total (-5.0%) and LDL-cholesterol (-6.7%) levels (all P<0.01). During the FO and the OO period serum adiponectin changes were significantly correlated with changes in erythrocyte %ALA (rs=0.34, P=0.007) and in erythrocyte %EPA (r(s)=0.47, P=0.01), respectively. CONCLUSIONS Daily consumption of FO did not confer any benefit in inflammatory or biochemical markers in normal weight young adults, who traditionally use olive oil as the main edible oil.

Cognitive health and Mediterranean Diet: Just diet or lifestyle pattern?

Mediterranean diet is a term used to describe the traditional eating habits of people in Crete, South Italy and other Mediterranean countries. It is a predominantly plant-based diet, with olive oil being the main type of added fat. There are many observational studies exploring the potential association between adherence to the Mediterranean diet and cognitive decline. The present review focuses on longitudinal studies with repeated cognitive assessments. It also evaluates evidence on behaviors related to the Mediterranean way of living, that have been shown to be associated with cognition, namely social interaction, participation in leisure activities, including physical activities, and sleep quality. The synergistic association-effect of these lifestyle behaviors, including diet, is unknown. Lifestyle patterns may constitute a new research and public health perspective.

Adherence to the Mediterranean Diet is Associated With Lower Likelihood of Breast Cancer: A Case-Control Study

Mediterranean diet has long been associated with human health. However, its relationship with breast cancer remains not well understood and appreciated. The aim of this work was to evaluate the association between adherence to the Mediterranean diet and its inherent constituents, with breast-cancer. Two-hundred-and-fifty consecutive, newly diagnosed breast-cancer female patients (56 ± 12 yr) and 250, 1-to-1 age-matched with the patients, controls, were studied. A standardized, validated questionnaire assessing various sociodemographic, clinical, lifestyle, and dietary characteristics, was applied through face-to-face interviews. Adherence to the Mediterranean diet was evaluated using the 11-components MedDietScore (theoretical range 0–55). Multiple logistic regression was applied to test the research hypothesis, whereas discriminant analysis was used to explore the strength of each component in relation to the outcome. One unit increase in the MedDietScore (i.e., greater adherence to the Mediterranean diet) was associated with 9% lower likelihood of having breast cancer (odds ratio = 0.91; 95% confidence interval, 0.86, 0.97). Decomposition of the MedDietScore revealed that the most important components and with beneficial effect were nonrefined cereals, vegetables, fruits, and alcohol, followed by red meat, but with unfavorable effect. A dietary recommendation for healthy eating, close to the Mediterranean dietary pattern, seems promising for breast cancer prevention.

Dietary factors associated with plasma high molecular weight and total adiponectin levels in apparently healthy women

OBJECTIVE Our aim was to investigate associations between dietary factors and high molecular weight (HMW) as well as total adiponectin in a sample of apparently healthy adult Mediterranean women. DESIGN AND METHODS Two hundred and twenty women were enrolled in this study. Anthropometric and body composition measurements were performed in all subjects. Fasting blood samples were taken; HMW and total adiponectin concentrations were measured. Food intake was evaluated using 3-day food records. The frequency of consumption of several food groups was approximately quantified in terms of number of servings per day. Furthermore, dietary intakes of betaine, choline, and free choline were estimated. RESULTS Women in the highest HMW adiponectin tertile had higher fruit intake compared with those with lower levels, after adjusting for potential confounders (P=0.04). On the contrary, dietary betaine and choline intakes were not different among HMW adiponectin tertiles. In linear models, fruit consumption, controlling for biological and lifestyle variables, was significantly related to HMW adiponectin (partial r=0.15, P=0.04), but the association with total adiponectin did not reach statistical significance (partial r=0.11, P=0.12). A significant negative correlation between total adiponectin and refined cereals was also observed (partial r=-0.16, P=0.03). DISCUSSION This is the first study that evaluates associations between dietary factors and HMW adiponectin levels. The associations found are moderate and indicate that, after multivariate adjustment, fruit consumption is related to HMW adiponectin in both linear and nonlinear models.

The Val81 missense mutation of the melanocortin 3 receptor gene, but not the 1908C/T nucleotide polymorphism in lamin A/C gene, is associated with hyperleptinemia and hyperinsulinemia in obese Greek Caucasians

Obesity-related phenotypes have been linked to human chromosomes 1q21 and 20q13, regions where the lamin A/C gene (LMNA) and the melanocortin 3 receptor gene (MC3R) map, respectively. Recently, a common single nucleotide polymorphism (SNP) in LMNA (1908C/T) was associated with plasma leptin and obesity indices in aboriginal Canadians, but these associations have not yet been explored in other populations. In contrast, no significant associations of MC3R variants with obesity have been detected, although a significant association with hyperinsulinemia has been reported in Caucasian populations. We investigated the associations between the LMNA 1908C/T variant and the 241G/A variant of the MC3R gene (Val81Ile missense mutation) and body composition, as well as plasma leptin and insulin levels, in two samples of unrelated healthy Greek subjects. A group of 112 young nonobese subjects, and a group of 116 adult women with a body mass index (BMI) ranging from 23.2 to 47.7 kg/m2 were studied cross-sectionally. We found no significant association of the LMNA 1908C/T and a borderline significant association of MC3R 241G/A SNPs with body composition variables, in the entire study sample. However, unlike the LMNA 1908C/T genetic variation, the MC3R 241G/A genetic variation was significantly associated with hyperleptinemia and huperinsulinemia in obese subjects, and there was evidence of interaction between this polymorphism and fat mass or BMI in predicting hyperinsulinemia. Our results suggest that the LMNA 1908C→T substitution and the Val81Ile mutation of the MC3R gene are unlikely to be major predictors of body composition in Greek Caucasians, but the latter genetic variation may predispose obese subjects to develop insulin and leptin resistance. Future studies are needed to confirm these data and assess whether individuals carrying this mutation are more resistant to weight-reducing and insulin-sensitizing treatments.

The J-shape association of ethanol intake with total homocysteine concentrations: the ATTICA study

BackgroundEpidemiological studies suggest a non-monotonic effect of alcohol consumption on cardiovascular risk, while there is strong evidence concerning the involvement of homocysteine levels on thrombosis. The aim of this work was to evaluate the association between usual ethanol consumption and homocysteine levels, in cardiovascular disease free adults.MethodsFrom May 2001 to December 2002 we randomly enrolled 1514 adult men and 1528 women, without any evidence of cardiovascular disease, stratified by age – gender (census 2001), from the greater area of Athens, Greece. Among the variables ascertained we measured the daily ethanol consumption and plasma homocysteine concentrations.ResultsData analysis revealed a J-shape association between ethanol intake (none, <12 gr, 12 – 24 gr, 25 – 48 gr, >48 gr per day) and total homocysteine levels (mean ± standard deviation) among males (13 ± 3 vs. 11 ± 3 vs. 14 ± 4 vs. 18 ± 5 vs. 19 ± 3 μmol/L, respectively, p < 0.01) and females (10 ± 4 vs. 9 ± 3 vs. 11 ± 3 vs. 15 ± 4 vs. 17 ± 3 μmol/L, respectively, p < 0.01), after controlling for several potential confounders. The lowest homocysteine concentrations were observed with ethanol intake of < 12 gr/day (Bonferroni α* < 0.05). No differences were observed when we stratified our analysis by type of alcoholic beverage consumed.ConclusionWe observed a J-shape relationship between homocysteine concentrations and the amount of ethanol usually consumed.

Association between adherence to the Mediterranean diet and semen quality parameters in male partners of couples attempting fertility

STUDY QUESTION Is adherence to the Mediterranean diet (MedDiet) associated with better semen quality in men of subfertile couples attempting fertility? SUMMARY ANSWER Greater adherence to the MedDiet, as assessed through the validated Mediterranean diet score (MedDietScore), was significantly associated with higher sperm concentration, total sperm count and sperm motility. WHAT IS KNOWN ALREADY A-posteriori dietary pattern approaches have revealed that dietary patterns characterized by high intakes of fruits, vegetables, whole grains, fish and low intake of meat are associated with better semen quality. Yet, whether adherence to the MedDiet is associated with better semen profile remains largely unexplored. STUDY DESIGN, SIZE, AND DURATION This was a cross-sectional study of 225 men from couples attending a fertility clinic in Athens, Greece, recruited between November 2013 and May 2016. The study was designed to evaluate the influence of habitual dietary intake and lifestyle on fertility outcomes. PARTICIPANTS/MATERIALS, SETTING, METHODS Men aged 26–55 years, 51.1% overweight or obese, 20.9% smokers, with complete dietary data were analyzed. Diet was assessed via a food-frequency questionnaire and adherence to the MedDiet was assessed through the MedDietScore (range: 0–55; higher scores indicating greater adherence to MedDiet). Semen quality was evaluated according to World Health Organization 2010 guidelines. Multiple logistic regression analysis was used to evaluate associations between tertiles of the MedDietScore and the likelihood of having abnormal semen parameters, after adjusting for potential confounders. MAIN RESULTS AND THE ROLE OF CHANCE Compared to men in the highest tertile of the MedDietScore (≥37, N = 66), a higher percentage of men in the lowest tertile of the score (⩽30, N = 76) exhibited below the WHO reference values for sperm concentration (47.4% vs 16.7%, P < 0.001), total sperm count (55.3% vs 22.7%, P < 0.001), total motility (65.8% vs 31.8%, P < 0.001), progressive motility (84.2 vs 62.1%, P = 0.011) and sperm morphology (50.0 vs 28.8%, P = 0.023). In the multivariable adjusted models, men in the lowest tertile of the MedDietScore had ~2.6 times higher likelihood of having abnormal sperm concentration, total sperm count and motility, compared to men in the highest tertile of the score. LIMITATIONS, REASONS FOR CAUTION The main limitation of the study stems from its cross-sectional nature, limiting our ability to determine causality. WIDER IMPLICATIONS OF THE FINDINGS The results suggest that greater compliance to the MedDiet may help improve semen quality. Whether this translates into differences in male fertility remains to be elucidated. Our findings are consistent with previous studies showing that dietary patterns with some of the characteristics of the MedDiet, i.e. rich in fruit, vegetables, legumes and whole grains, are associated with better measures of semen quality. STUDY FUNDING/COMPETING INTEREST(S) No funding was obtained. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER n/a

Genetic variation within IL18 is associated with insulin levels, insulin resistance and postprandial measures

Background and aims IL-18 expression is up-regulated in atherosclerotic plaques, and higher levels are seen in obese and Type 2 Diabetic individuals. More recently, a possible role for IL-18 in glucose and energy homeostasis has been suggested. Methods and results We investigated variation within the IL18 gene and its association with measures of obesity and the metabolic syndrome. Five IL18 tagging single nucleotide polymorphisms (rs1946519, rs2043055, rs549908, rs360729, rs3882891) were selected and genotyped in the Gene-Diet Attica Investigation on childhood obesity (GENDAI) (age range 10–14 yrs); in young European men in the second European Atherosclerosis Research offspring Study (EARSII), an offspring study (age range 18–28 yrs) and in a group of healthy women from the Greek Obese Women study (GrOW) (age range 18–74 yrs). Six common haplotypes were observed. In GrOW, Hap6 (Frequency-2.6%) was associated with higher insulin levels (p < 0.0001), estimates of HOMA-Insulin Resistance (p < 0.0001) and HOMA-β-cell (p < 0.0001) compared to the common haplotype Hap1 (Frequency-33.2%). In EARSII, rs2043055 was associated with peak and area under the curve triglycerides (p = 0.001 and p = 0.002, respectively) after an oral fat tolerance test in ‘cases’ but not ‘controls’. None of the haplotypes were associated with measures of body fatness in any of the studies. Conclusion Association of IL18 variation with insulin levels and estimates of insulin resistance were only observed in our adult study, suggesting that the effects of IL-18 are only associated with increasing age. Taken together with the association of IL18 variants with post-prandial measures, this provides support for IL-18 as a metabolic factor.