Host genotype, intestinal microbiota and inflammatory disorders.

Intestinal microbiota may influence human physiology and disease risk due to the role it plays in mediating appropriate immune responses to harmful and innocuous antigens. Colonisation of the intestine in early life seems particularly important as it is the main environmental stimulus for immune system maturation. This is a dynamic process, which depends on both environmental and genetic factors. The pathogenesis of inflammatory bowel disease, such as Crohn's disease, involves genetic polymorphisms (e.g. CARD15/nucleotide-binding oligomerisation domain 2) related to an excessive inflammatory response to commensal microbiota and to its unbalanced composition. Atopic diseases have also been linked to imbalances in microbiota and to related genetic factors (e.g. TLR4 and CD14 genes), although these associations are still controversial. Research into the relationship between the genetic risk of developing celiac disease (human leukocyte antigen (HLA)-DQ2/DQ8) and the early colonisation process in infants at family risk of the disease has also reported that the HLA-DQ genotype could influence staphylococcal colonisation. Future observational studies considering both host genetics and microbiota could be critical in defining the complex host-microbe interactions and the respective role each plays in inflammatory disorders.

Biofortified black beans in a maize and bean diet provide more bioavailable iron to piglets than standard black beans.

Our objective was to compare the capacities of biofortified and standard black beans (Phaseolus vulgaris L.) to deliver iron (Fe) for hemoglobin (Hb) synthesis. Two lines of black beans, one standard and the other biofortified (high) in Fe (71 and 106 microg Fe/g, respectively), were used. Maize-based diets containing the beans were formulated to meet the nutrient requirements for swine except for Fe (Fe concentrations in the 2 diets were 42.9 +/- 1.2 and 54.6 +/- 0.9 mg/kg). At birth, pigs were injected with 50 mg of Fe as Fe dextran. At age 28 d, pigs were allocated to the experimental diets (n = 10). They were fed 2 times per day for 5 wk and given free access to water at all times. Body weights and Hb concentrations were measured weekly. Hb repletion efficiencies (means +/- SEM) did not differ between groups and, after 5 wk, were 20.8 +/- 2.1% for the standard Fe group and 20.9 +/- 2.1% for the high Fe group. Final total body Hb Fe contents did not differ between the standard [539 +/- 39 mg (9.7 +/- 0.7 micromol)] and high Fe [592 +/- 28 mg (10.6 +/- 0.5 micromol)] bean groups (P = 0.15). The increase in total body Hb Fe over the 5-wk feeding period was greater in the high Fe bean group [429 +/- 24 mg (7.7 +/- 0.4 micromol)] than in the standard Fe bean group [361 +/- 23 mg (6.4 +/- 0.4 micromol)] (P = 0.034). We conclude that the biofortified beans are a promising vehicle for increasing intakes of bioavailable Fe in human populations that consume beans as a dietary staple.