Prevalence of Gene Variants Associated with Poor Absorption or Negative Interactions with Key Anti-Inflammatory Nutrients in a New Zealand Population ^†

Background: New Zealand (NZ) has high rates of Crohn’s disease (CD) at 26/10⁵. Having gene variants associated with low levels of betacarotene, vitamin D and Omega-3 polyunsaturated fatty acids can impede the immune response. Not known was the prevalence of these variants in the CD population in NZ.

Methods: We determined the prevalence of these gene variants in NZ adults in two matched groups, one with CD (n = 416) and a control group of healthy adults (n = 649) selected from adult subjects in the ‘Genes and Diet in Inflammatory Bowel Disease Study’ of Nutrigenomics NZ. The selected SNPs included those associated with genes with betacarotene absorption BCMO1-Betacarotene 15,15′-monooxygenase-1, (rs12934922, rs7501331); vitamin D concentrations in the genes GC-Group-specific component (rs2282679, rs4588, rs1155563), the Cytochrome P450 family: CYP24A1-(rs1699913), CYP2R1 (rs10741657), and DHCR7/NADSYN1 7-dehydrocholesterol reductase (rs3829251,rs12785878); with fatty acid desaturases genes which influence omega-three and-six fatty acid metabolism: FADS1, FADS2 (rs174556, rs174570, rs2072114, rs174583 & rs174589); with the Peroxisome proliferator-activated- receptor genes relating to: cholesterol levels PPARA (rs4253728); and with CD activity. PPARG (rs1801282); X-ray repair cross-complementing protein 1, XRCC1 (rs25487) associated with colorectal adenoma, and SCD- Stearoyl-coA desaturase (rs 2060792) with inflammation. These genotypes were assessed using custom SNP Sequenom MassARRAY analyses.

Results: The three variants: TT in rs12934922, (BCM01); GG in rs10741657, (CYP2R1) and TT in rs174583 (FADS2) had a representation of more than 16%. The- frequencies of these SNPs known to associate with low betacarotene absorption and vitamin D concentration and negative fatty acid interactions respectively, were 18, 39 and 16% in both the healthy as well as the CD groups in these cohorts.. These frequencies are similar to other reported healthy European groups of 24, 38 and 13%.

Conclusion: Around 16%–39% of the NZ population maybe deprived of these anti-inflammatory nutrient requirements due to these variant genotypes.