Optimal maternal long-chain PUFA (LCPUFA) status is essential for the developing fetus. The fatty acid desaturase (FADS) genes are involved in the endogenous synthesis of LCPUFA. The minor allele of various FADS SNP have been associated with increased maternal concentrations of the precursors linoleic acid (LA) and α-linolenic acid (ALA), and lower concentrations of arachidonic acid (AA) and DHA. There is limited research on the influence of FADS genotype on cord PUFA status. The current study investigated the influence of maternal and child genetic variation in FADS genotype on cord blood PUFA status in a high fish-eating cohort. Cord blood samples (n 1088) collected from the Seychelles Child Development Study (SCDS) Nutrition Cohort 2 (NC2) were analysed for total serum PUFA. Of those with cord PUFA data available, maternal (n 1062) and child (n 916), FADS1 (rs174537 and rs174561), FADS2 (rs174575), and FADS1-FADS2 (rs3834458) were determined. Regression analysis determined that maternal minor allele homozygosity was associated with lower cord blood concentrations of DHA and the sum of EPA + DHA. Lower cord blood AA concentrations were observed in children who were minor allele homozygous for rs3834458 (β = 0·075; P = 0·037). Children who were minor allele carriers for rs174537, rs174561, rs174575 and rs3834458 had a lower cord blood AA:LA ratio (P < 0·05 for all). Both maternal and child FADS genotype were associated with cord LCPUFA concentrations, and therefore, the influence of FADS genotype was observed despite the high intake of preformed dietary LCPUFA from fish in this population.

The association of MeHg exposure through fish consumption on human autoimmunity remains unclear. Fish also contain n-3 long chain polyunsaturated fatty acids (LCPUFA) that are known to regulate inflammation and mitigate autoimmune disease symptoms. We studied the association of low-level exposure to methylmercury (MeHg) through fish consumption in the SCDS. We examined this association at age 19 years in the SCDS Main Cohort (n = 497). We measured MeHg exposure at 3 time points [prenatal, weighted average (6 months to 19 years) and concurrent (19 years) and LCPUFA status and a panel of 13 autoimmune markers at age 19 years. The autoimmune markers included antinuclear antibodies (ANA), anti-dsDNA and anti-RNP, and total (non-specific) immunoglobulins (Ig) IgG, IgA, and IgM. A combined ANA variable was also calculated based on being within or above reference range for any of the ANA markers; 56% of the subjects met this criterion. Multivariable regression models adjusted for prenatal MeHg, sex and waist circumference, with and without adjustment for LCPUFA, were fit for the three MeHg exposure metrics and each immune marker. Mean (SD) prenatal, weighted average and concurrent MeHg was 6.84 (4.55), 7.46 (2.82), and 10.23 (6.02) ppm, respectively. Combined ANA was positively associated with concurrent MeHg following adjustment for the n6:n3 LCPUFA ratio (β = 0.036, 95%; CI: 0.001, 0.073). Prenatal and average MeHg exposures were not significantly associated with any individual ANA. IgM was negatively associated with concurrent (β = -0.016, 95%CI: -0.016, -0.002), and average (β = -0.042, 95%CI: -0.042, -0.009) MeHg exposure in the models adjusted for n-3, n-6 LCPUFA and when separately adjusted for the n6:n3 LCPUFA ratio. Total (19-year) n-3 PUFA status was negatively associated with anti-RNP (β = -20.355, 95%CI: -36.89, -4.34) and IgG (β = -1.384, 95%CI: -2.682, -0.087). Total n-3 LCPUFA was associated with lower markers of autoimmunity. MeHg exposure at 19 years was associated with higher ANA and lower IgM but only following adjustment for LCPUFA. The clinical significance of these findings is unclear and further research is warranted to determine if these associations precede autoimmune disease development.

Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case–control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case–case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.

We tested the applicability of the “passive sampling” hypothesis and theory of island biogeography (TIB) for explaining the diversity of forest-dwelling carabid assemblages (Carabidae: Coleoptera) on 30 forested islands (0.2–980.7 ha) in Lac la Ronge and the adjacent mainland in Saskatchewan, Canada. Species richness per unit area increased with distance to mainland with diversity being highest on the most isolated islands. We detected neither a positive species-area relationship, nor significant differences in species richness among island size classes, or between islands and the mainland. Nonetheless, carabid assemblages distinctly differed on islands <1 ha in area and gradually approached the structure of mainland assemblages as island area increased. Small islands were characterised by abundant populations of small-bodied, winged species and few if any large-bodied, flightless species like Carabus taedatus Fabricius. Our findings suggest that neither the “passive sampling” hypothesis nor the theory of island biogeography adequately explain carabid beetle diversity patterns observed among islands in Lac la Ronge. Instead, we hypothesise that population processes such as higher extinction rates of large-bodied, flightless species and the associated release of smaller-bodied, flying species from intra-guild predation on small islands contribute to observed differences in the structure of carabid assemblages between islands.