Bacterial butyrate prevents atherosclerosis

The short fatty acid, butyrate, which is produced by intestinal anaerobic bacteria in the colon, has inhibitory activity on histone deacetylases (HDACs). Treatment of the human colon cancer cell line, LS174T, with 1-2 mM sodium butyrate stimulated MUC2 mucin production, as determined by histological PAS staining of carbohydrate chains of mucin, and confirmed at the protein and mRNA levels by immunoblotting with anti-MUC2 antibody and real-time RT-PCR, respectively. Increases in acetylated histone H3 in the LS174T cells treated with butyrate suggest inhibition of HDACs in these cells. Butyrate-stimulated MUC2 production in the LS174T cells was inhibited by the MEK inhibitor, U0126, implicating the involvement of extracellular signal-regulated kinase (ERK) cascades in this process. Proliferation of the LS174T cells was inhibited by butyrate treatment. Although apoptotic nuclear DNA fragmentation could not be detected, cell-cycle arrest at the G0/G1 phase in the butyrate-treated cells was demonstrated by flow cytometry. Thus butyrate, an HDAC inhibitor, inhibits proliferation of LS174T cells but stimulates MUC2 production in individual cells.

Prospective studies suggest that dietary fiber intake, especially water-soluble fiber, may be inversely associated with the risk of coronary heart disease (CHD). We examined the relationship between total and soluble dietary fiber intake and the risk of CHD and cardiovascular disease (CVD) in 9776 adults who participated in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study and were free of CVD at baseline. A 24-hour dietary recall was conducted at the baseline examination, and nutrient intakes were calculated using Food Processor software. Incidence and mortality data for CHD and CVD were obtained from medical records and death certificates during follow-up. During an average of 19 years of follow-up, 1843 incident cases of CHD and 3762 incident cases of CVD were documented. Compared with the lowest quartile of dietary fiber intake (median, 5.9 g/d), participants in the highest quartile (median, 20.7 g/d) had an adjusted relative risk of 0.88 (95% confidence interval [CI], 0.74-1.04; P =.05 for trend) for CHD events and of 0.89 (95% CI, 0.80-0.99; P =.01 for trend) for CVD events. The relative risks for those in the highest (median, 5.9 g/d) compared with those in the lowest (median, 0.9 g/d) quartile of water-soluble dietary fiber intake were 0.85 (95% CI, 0.74-0.98; P =.004 for trend) for CHD events and 0.90 (95% CI, 0.82-0.99; P =.01 for trend) for CVD events. A higher intake of dietary fiber, particularly water-soluble fiber, reduces the risk of CHD.