The effect of dietary resistant starch type 2 on the microbiota and markers of gut inflammation in rural Malawi children.

BACKGROUND: Resistant starch (RS) decreases intestinal inflammation in some settings. We tested the hypothesis that gut inflammation will be reduced with dietary supplementation with RS in rural Malawian children. Eighteen stunted 3-5-year-old children were supplemented with 8.5 g/day of RS type 2 for 4 weeks. The fecal samples were analyzed for the microbiota, the microbiome, short chain fatty acids, metabolome, and proteins indicative of inflammation before and after the intervention. Subjects served as their own controls. RESULTS: The consumption of RS changed the composition of the microbiota; at the phylum level Actinobacteria increased, while Firmicutes decreased. Among the most prevalent genera, Lactobacillus was increased and Roseburia, Blautia, and Lachnospiracea incertae sedis were decreased. The Shannon H index at the genus level decreased from 2.02 on the habitual diet and 1.76 after the introduction of RS (P < 0.01). Fecal acetate concentration decreased, and fecal propionate concentration increased after RS administration (-5.2 and 2.0 µmol/g, respectively). Fecal calprotectin increased from 29 ± 69 to 89 ± 49 µg/g (P = 0.003) after RS was given. The lipopolysaccharide biosynthesis pathway was upregulated. CONCLUSIONS: Our findings do not support the hypothesis that RS reduces gut inflammation in rural Malawian children.

Childhood helminth exposure is protective against inflammatory bowel disease: a case control study in South Africa.

BACKGROUND: Inflammatory bowel disease (IBD) is more common in countries with improved hygiene, suggesting that environmental exposures may be associated with its development. The primary objective of this study was to examine the association between self-reported childhood helminth infection and the development of IBD in South Africa. METHODS: Unmatched case-control study. Logistic regression was used to model associations with IBD. RESULTS: There were 88 patients with Crohn's disease (CD), 63 with ulcerative colitis (UC), and 219 control subjects. Of the 151, 93 (61.6%) IBD subjects (35 of 63 [55.6%] had UC and 58 of 88 [65.9%] had CD) reported childhood helminth exposure compared with 200 of 219 (91.3%) non-IBD subjects (P < 0.001). Helminth infection (adjusted odds ratio [AOR] = 0.2; 95% confidence interval [CI], 0.1-0.4), shared housing (AOR = 0.1; 95% CI, 0.04-0.4), and raw beef consumption (AOR = 0.2; 95% CI, 0.1-0.6) were protective, whereas urban dwelling (AOR = 4.2; 95% CI, 2.0-8.8) and parental tertiary education (AOR = 18.2; 95% CI, 3.2-103.7) were associated with CD. Helminth infection (AOR = 0.2; 95% CI, 0.1-0.6), mixed race (AOR = 0.1; 95% CI, 0.03-0.5), smoking (AOR = 0.2; 95% CI, 0.07-0.5), shared housing (AOR = 0.1; 95% CI, 0.01-0.4), and raw beef consumption (AOR = 0.1; 95% CI 0.04-0.5) were protective against UC, whereas parental tertiary education (AOR = 12.7; 95% CI, 1.0-157.4) was associated with UC. CONCLUSION: This study demonstrates a protective association of childhood helminth infection against the development of IBD and supports the "hygiene hypothesis" that improved living conditions may increase the incidence of IBD. Our epidemiologic conclusions provide support that helminths may have immunomodulatory effects which provides protection against the development of IBD later in life.