Long-term intake of dietary fat and risk of ulcerative colitis and Crohn's disease

Association between high dietary intake of the n-3 polyunsaturated fatty acid docosahexaenoic acid and reduced risk of Crohn's disease

BACKGROUND

There are plausible mechanisms for how dietary docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, could prevent Crohn's disease (CD).

AIM

To conduct a prospective study to investigate the association between increased intake of DHA and risk of CD.

METHODS

Overall, 229 702 participants were recruited from nine European centres between 1991 and 1998. At recruitment, dietary intakes of DHA and fatty acids were measured using validated food frequency questionnaires. The cohort was monitored through to June 2004 to identify participants who developed incident CD. In a nested case-control analysis, each case was matched with four controls; odds ratios (ORs) were calculated for quintiles of DHA intake, adjusted for total energy intake, smoking, other dietary fatty acids, dietary vitamin D and body mass index.

RESULTS

Seventy-three participants developed incident CD. All higher quintiles of DHA intake were inversely associated with development of CD; the highest quintile had the greatest effect size (OR = 0.07; 95% CI = 0.02-0.81). The OR trend across quintiles of DHA was 0.54 (95% CI = 0.30-0.99, Ptrend  = 0.04). Including BMI in the multivariate analysis, due to its correlation with dietary fat showed similar associations. There were no associations with the other dietary fatty acids studied.

CONCLUSION

There were inverse associations, with a biological gradient between increasing dietary docosahexaenoic acid intakes and incident Crohn's disease. Further studies in other populations should measure docosahexaenoic acid to determine if the association is consistent and the hypothesis tested in randomised controlled trials of purely docosahexaenoic acid supplementation.

Intake of Chlorella vulgaris improves antioxidative capacity in rats oxidatively stressed with dietary cadmium

BACKGROUND/AIMS

This study was designed to examine the antioxidative capacity of chlorella in rats oxidatively stressed with dietary cadmium (Cd).

METHOD

Sixty male Sprague-Dawley rats (14 weeks old) were fed diets containing 0, 3 or 5% chlorella, and 0 or 160 ppm Cd for 10 weeks. Activities of antioxidant enzymes and xanthine oxidase (XO), lipid peroxide concentration and superoxide radical generation were examined in blood and liver.

RESULTS

Erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activities were not different among the groups. Cd treatment significantly lowered liver SOD and GPx activities; however, there were no differences induced by the chlorella content. Dietary Cd markedly increased XO activities in plasma and liver. Five percent chlorella-containing diets significantly lowered plasma XO activity, 3% chlorella-containing diets significantly lowered liver XO activity. Plasma malondialdehyde (MDA) concentration of the Cd-3% chlorella group was significantly lower than that of the Cd-0% chlorella group. Liver MDA concentration of the Cd-5% chlorella group was significantly lower than that of the Cd-0% chlorella group. Increased serum and liver superoxide radical generation by Cd was significantly attenuated by chlorella intake.

CONCLUSION

Chlorella could be applied as potential substance for reducing oxidative stress, since XO activity, MDA concentration and superoxide radical generation were decreased by chlorella intake.