Fat intake may affect Crohn’s disease activity through genes
MedWire News: Different types of fat in the diet can interact with cytokine genotype to affect the activity of Crohn’s disease (CD), research indicates.
Environmental and host genetic factors are important for determining susceptibility to CD and disease behavior, say the researchers.
Earlier studies suggested that differences in the type of dietary fat may be important in modulating intestinal inflammation, with n-3 polyunsaturated fatty acid (PUFA) having a protective role compared with n-6 PUFAs.
In this study, Catarina Sousa Guerreiro (Lisbon University, Portugal) and colleagues examined the effect of polymorphisms in pro- and anti-inflammatory cytokines in modifying susceptibility to CD and disease activity.
Specifically, the team investigated seven single-nucleotide polymorphisms (SNPs) in interleukin (IL)1, tumor necrosis factor (TNF)alpha, lymphotoxin (LT)alpha, and IL6 genes in 99 CD patients and 116 control individuals.
Individuals homozygous for the IL6 174G/C polymorphism had an increased risk for developing CD compared with control participants, with an odds ratio (OR) of 6.1 for the CC versus the wild-type GG genotype.
The TT genotype on the TNFalpha -857 locus was the sole polymorphism associated with higher disease activity, with an OR of 10.4 compared with the wild-type CC genotype.
A diet rich in monounsaturated fats was associated with more active disease, and there was an interaction between dietary fat intake and the SNPs, the team reports in the American Journal of Gastroenterology.
A high intake of total, saturated, and monounsaturated fats, and a higher ratio of n-6 to n-3 PUFAs, were associated with higher disease activity, mainly in patients carrying variant alleles of the 857 TNFalpha polymorphism, in who the ORs for the three fat conditionswere 6.0, 5.17, and 5.92, respectively.
A similar association was observed between high intake of these fats and the 174 IL6 polymorphism, although it was not statistically significant.
The researchers conclude: “These results show that different types of fat may interact with cytokine genotype, modulating disease activity.”
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By Anita Wilkinson