Background: Vitamin D (vitD) supplementation may prolong remission in Crohn's disease (CD); however, the clinical efficacy and mechanisms are unclear.Aim: To determine changes in intestinal permeability (IP), antimicrobial peptide (AMP) concentrations and disease markers in CD, in response to vitD supplementation.Methods: In a double‐blind randomised placebo‐controlled study, we assigned 27 CD patients in remission to 2000 IU/day vitD or placebo for 3 mos. We determined IP, plasma cathelicidin (LL‐37 in ng/mL), human‐beta‐defensin‐2 (hBD2 in pg/mL), disease activity (Crohn's Disease Activity Index (CDAI)), C‐reactive protein (CRP in mg/L), fecal calprotectin (µg/g), Quality of Life (QoL) and serum 25‐hydroxyvitamin D (25(OH)D in nmol/L) at 0 and 3 mos.Results: At 3 mos., 25(OH)D concentrations were significantly higher in those whom were treated (p < 0.001). Intra‐group analysis showed increased LL‐37 concentrations (p = 0.050) and maintenance of IP measures in the treated group. In contrast, in the placebo group, the small bowel (p = 0.018) and gastro‐duodenal permeability (p = 0.030) increased from baseline. At 3 mos., patients with 25(OH)D ≥ 75 nmol/L had significantly lower CRP (p = 0.019), higher QoL (p = 0.037), higher LL‐37 concentrations (p < 0.001) and non‐significantly lower CDAI scores (p = 0.082), compared to those with levels <75 nmol/L.Conclusion: Short‐term treatment with 2000 IU/day vitD significantly increased 25(OH)D levels in CD patients in remission and it was associated with increased LL‐37 concentrations and maintenance of IP. Achieving 25(OH)D ≥ 75 nmol/l was accompanied by higher circulating LL‐37, higher QoL scores and reduced CRP. Registered at ClinicalTrials.gov (NCT01792388).

(1) Background/Objectives: The relationship between body mass index (BMI) and probable sarcopenia, a precursor to sarcopenia diagnosis, is unclear. While low BMI has been associated with sarcopenia risk, some evidence suggests that obesity may confer protection. We aimed to investigate the association between probable sarcopenia and BMI and, furthermore, to explore associations with waist circumference (WC). (2) Methods: This cross-sectional study included 5783 community-dwelling adults (mean age 70.4 ± 7.5 years) from Wave 6 of the English Longitudinal Study of Ageing (ELSA). Probable sarcopenia was defined using the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria for low hand grip strength and/or slow chair rise. Associations between BMI and probable sarcopenia were examined using multivariable regression analysis and were similarly performed for WC. (3) Results: Our overall findings show that an underweight BMI was significantly associated with an increased likelihood of probable sarcopenia [OR (CI) 2.25 (1.17, 4.33), p = 0.015]. For higher BMI categories, the findings were conflicting. Overweight and obesity were associated with an increased likelihood of probable sarcopenia when defined by lower limb strength alone, [OR (CI), 2.32 (1.15, 4.70), p = 0.019; 1.23 (1.02, 1.49), p = 0.35, and 1.49 (1.21, 1.83), p < 0.001, respectively]. In contrast, overweight and obesity appeared protective when probable sarcopenia was assessed by low hand grip strength alone [OR (CI) 0.72 (0.60, 0.88), p = 0.001, and 0.64 (0.52, 0.79), p < 0.001, respectively]. WC was not significantly associated with probable sarcopenia on multivariable regression analysis. (4) Conclusion: This study supports the evidence that low BMI is associated with an increased likelihood of probable sarcopenia, highlighting an important at-risk group. The findings for overweight and obesity were inconsistent and may be measurement dependent. It seems prudent that all older adults at risk of probable sarcopenia, including those with overweight/obesity, are assessed to prevent underdetection of probable sarcopenia alone or with the double burden of obesity.