Meta-analysis of genes in commercially available nutrigenomic tests denotes lack of association with dietary intake and nutrient-related pathologies

Nutrigenomics is an emerging discipline that aims to investigate how individual genetic composition correlates with dietary intake, as well as how nutrition influences gene expression. Herein, the fundamental question relates to the value of nutrigenomics testing on the basis of the currently available scientific evidence. A thorough literature search has been conducted in PubMed scientific literature database for nutrigenomics research studies on 38 genes included in nutrigenomics tests provided by various private genetic testing laboratories. Data were subsequently meta-analyzed to identify possible associations between the genes of interest and dietary intake and/or nutrient-related pathologies. Data analysis occurred according to four different models due to data sparsity and inconsistency. Data from 524,592 individuals (361,153 cases and 163,439 controls) in a total of 1,170 entries were obtained. Conflicting findings indicated that there was a great incompatibility regarding the associations (or their absence) identified. No specific-and statistically significant-association was identified for any of the 38 genes of interest. In those cases, where a weak association was demonstrated, evidence was based on a limited number of studies. As solid scientific evidence is currently lacking, commercially available nutrigenomics tests cannot be presently recommended. Notwithstanding, the need for a thorough and continuous nutrigenomics research is evident as it is a highly promising tool towards precision medicine

Associations of the FTO rs9939609 and the MC4R rs17782313 polymorphisms with type 2 diabetes are modulated by diet : being higher when adherence to the Mediterranean diet pattern is low

Abstract Background: Although the Fat Mass and Obesity (FTO) and Melanocortin-4 Receptor (MC4R) genes have been consistently associated with obesity risk, the association between the obesity-risk alleles with type 2 diabetes is still controversial. In some recent meta-analyses in which significant results have been reported, the associations disappeared after adjustment for body mass index (BMI). However gene-diet interactions with dietary patterns have not been investigated. Our main aim was to analyze whether these associations are modulated by the level of adherence to the Mediterranean Diet (MedDiet). Methods: Case-control study in 7,052 high cardiovascular risk subjects (3,430 type 2 diabetes cases and 3,622 non-diabetic subjects) with no differences in BMI. Diet was assessed by validated questionnaires. FTO-rs9939609 and MC4R-rs17782313 were determined. An aggregate genetic score was calculated to test additive effects. Gene-diet interactions were analyzed. Results: Neither of the polymorphisms was associated with type 2 diabetes in the whole population. However, we found consistent gene-diet interactions with adherence to the MedDiet both for the FTO-rs9939609 (Pinteraction= 0.039), the MC4R-rs17782313 (P-interaction=0.009) and for their aggregate score (P-interaction=0.006). When adherence to the MedDiet was low, carriers of the variant alleles had higher type 2 diabetes risk (OR=1.21, 95%CI: 1.03-1.40; P=0.019 for FTO-rs9939609 and OR=1.17, 95%CI:1.01-1.36; P=0.035 for MC4R-rs17782313) than wild-type subjects. However, when adherence to the MedDiet was high, these associations disappeared (OR=0.97, 95%CI: 0.85-1.16; P=0.673 for FTO-rs9939609 and OR=0.89, 95%CI:0.78-1.02; P=0.097 for MC4R-rs17782313). These gene-diet interactions remained significant even after adjustment for BMI. As MedDiet is rich in folate, we also specifically examined folate intake and detected statistically significant interaction effects on fasting plasma glucose concentrations in non-diabetic subjects. However these findings should be interpreted with caution because folate intake may simply reflect a healthy dietary pattern. Conclusions: These novel results suggest that the association of the FTO-rs9939609 and the MC4R-rs17782313 polymorphisms with type 2 diabetes depends on diet and that a high adherence to the MedDiet counteracts the genetic predisposition. Keywords: Nutrigenetics, Mediterranean diet, Diabetes, FTO, MC4R, Gene-diet interaction

MicroRNA-410 regulated lipoprotein lipase variant rs13702 is associated with stroke incidence and modulated by diet in the randomized controlled PREDIMED trial

Background: MicroRNAs have emerged as important epigenetic regulators in cardiovascular diseases (CVDs). Using an observational meta-analysis design, we previously characterized a gain-offunction microRNA-410 target site polymorphism (rs13702T.C) in the 3#untranslated region of the lipoprotein lipase (LPL) gene. The C allele was associated with lower triglycerides, and this association was modulated by fat intake. Objectives: We aimed to extend our findings by assessing the interaction between the rs13702 polymorphism and fat intake on triglycerides at baseline and longitudinally by using a dietary intervention design. We also examined as a primary outcome the association of this variant with CVD incidence and its modulation by the Mediterranean diet (MedDiet). Design: We studied 7187 participants in the PREDIMED (Prevencion con Dieta Mediterranea) randomized trial that tested a MedDiet intervention compared with a control diet, with a median 4.8-y followup. LPL polymorphisms and triglycerides were determined and CVD assessed. Gene-diet interactions for triglycerides were analyzed at baseline (n = 6880) and after a 3-y intervention (n = 4131). Oxidative stress parameters were investigated in a subsample. Results: The rs13702T.C polymorphism was strongly associated with lower triglycerides in C allele carriers and interacted synergistically with dietary monounsaturated (P = 0.038) and unsaturated fat intake (P = 0.037), decreasing triglycerides at baseline. By 3 y, we observed a genediet interaction (P = 0.025) in which the C allele was associated with a greater reduction in triglycerides after intervention with MedDiet, high in unsaturated fat. Although the polymorphism was associated with lower stroke risk (HR: 0.74; 95% CI: 0.57, 0.97; P = 0.029 per C allele), this association reached statistical significance only in the MedDiet intervention (HR: 0.58; 95% CI: 0.37, 0.91; P = 0.019 in C compared with TT carriers), not in the control group (HR: 0.94; 95% CI: 0.55, 1.59; P = 0.805). Conclusion: We report a novel association between a microRNA target site variant and stroke incidence, which is modulated by diet in terms of decreasing triglycerides and possibly stroke risk in rs13702 C allele carriers after a high-unsaturated fat MedDiet intervention. This trial was registered at controlled-trials.com as ISRCTN35739639. Am J Clin Nutr 2014;100:719-31

Mediterranean Diet Reduces the Adverse Effect of the TCF7L2-rs7903146 Polymorphism on Cardiovascular Risk Factors and Stroke Incidence: A Randomized Controlled Trial in a High-Cardiovascular-Risk Population.

OBJECTIVE: Transcription factor 7-like 2 (TCF7L2) polymorphisms are strongly associated with type 2 diabetes, but controversially with plasma lipids and cardiovascular disease. Interactions of theMediterranean diet (MedDiet) on these associations are unknown. We investigated whether the TCF7L2-rs7903146 (C.T) polymorphism associations with type 2 diabetes, glucose, lipids, and cardiovascular disease incidence were modulated by MedDiet. RESEARCH DESIGNANDMETHODS: A randomized trial (twoMedDiet intervention groups and a control group) with 7,018 participants in the PREvención con DIetaMEDiterr anea study was undertaken and major cardiovascular events assessed. Data were analyzed at baseline and after a median follow-up of 4.8 years. Multivariable-adjusted Cox regression was used to estimate hazard ratios (HRs) for cardiovascular events. RESULTS: The TCF7L2-rs7903146 polymorphismwas associated with type 2 diabetes (odds ratio 1.87 [95% CI 1.62-2.17] for TT compared with CC). MedDiet interacted significantly with rs7903146 on fasting glucose at baseline (P interaction = 0.004).When adherence to theMedDiet was low, TT had higher fasting glucose concentrations (132.3 6 3.5 mg/dL) than CC+CT (127.3 6 3.2 mg/dL) individuals (P = 0.001). Nevertheless, when adherence was high, this increase was not observed (P = 0.605). This modulation was also detected for total cholesterol, LDL cholesterol, and triglycerides (P interaction,0.05 for all). Likewise, in the randomized trial, TT subjects had a higher stroke incidence in the control group (adjusted HR 2.91 [95%CI 1.36- 6.19]; P = 0.006 compared with CC), whereas dietary intervention with MedDiet reduced stroke incidence in TT homozygotes (adjustedHR 0.96 [95%CI 0.49-1.87]; P = 0.892 for TT compared with CC). CONCLUSIONS: Our novel results suggest that MedDiet may not only reduce increased fasting glucose and lipids in TT individuals, but also stroke incidence. Diabetes Care 36:3803-3811, 201