To examine whether the consumption of a Mediterranean diet (MedDiet), compared with a low-fat diet, interacts with two single nucleotide polymorphisms at the tumor necrosis factor alpha gene (rs1800629, rs1799964) in order to improve triglycerides (TG), glycemic control, and inflammation markers.
Methods and results
Genotyping, biochemical measurements, dietary intervention, and oral fat load test meal were determined in 507 metabolic syndrome (MetS) patients selected from all the subjects included in CORDIOPREV clinical trial (n = 1002). At baseline, G/G subjects (n = 408) at the rs1800629 polymorphism, showed higher fasting and postprandial TG (p = 0.003 and p = 0.025, respectively), and high sensitivity C-reactive protein (hsCRP) (p = 0.003) plasma concentrations than carriers of the minor A-allele (G/A + A/A) (n = 99). After 12 months of MedDiet, baseline differences between genotypes disappeared. The decrease in TG and hsCRP was statistically significant in G/G subjects (n = 203) compared with carriers of the minor A-allele (p = 0.005 and p = 0.034, respectively) (n = 48). No other gene–diet interactions were observed in either diet.
These results suggest that the rs1800629 at the tumor necrosis factor alpha gene interacts with MedDiet to influence TG metabolism and inflammation status in MetS subjects. Understanding the role of gene–diet interactions may be the best strategy for personalized treatment of MetS.
Alex's Notes: Here is another study showing the importance of n=1. By this I mean yourself and your personal genetics. What this is demonstrating is that the beneficial effects of the Mediterranean diet are at least partly mediated by the G/G polymorphism, which acts to increase fasting blood glucose and lipid levels. In other words, if you are genetically predisposed to be at risk for metabolic syndrome, the Mediterranean diet may help you. If not, then it won't make a statistically significant impact (this isn't saying it won't help, it is just saying that individual variances in response to the diet are too random to have a clear trend).