The effect of a natural high-fibre diet on faecal and biliary bile acids, faecal pH and whole-gut transit time in man. A controlled study.

Dietary fibre possibly protects against colonic cancer by effects on bile acid metabolism. We investigated the effect of a natural high-fibre diet on secondary bile acid formation. Twelve healthy subjects on an habitual low-fibre diet (for 4 weeks) consumed a high-fibre menu for 10 weeks (experimental group). A control group of 10 subjects consumed their regular high-fibre diet during this period. Faecal and biliary acid composition, faecal weight, faecal pH and gut transit time were studied before and after 6 and 10 weeks of fibre addition. Changes in the experimental group were compared to changes in the control group. The concentration, but not the excretion, of the secondary faecal bile acids was reduced in the experimental group. Faecal weight increased, faecal pH dropped and gut transit time was not altered. The biliary deoxycholic acid content decreased and the cholic acid content increased after 6 weeks, but returned to baseline values after 10 weeks of fibre addition. This study shows that a natural high-fibre diet lowers secondary faecal bile acid concentration through an increase in stool weight. The 7 alpha-dehydroxylation of primary bile acids is probably not or only transiently inhibited.

Isolated systolic hypertension in Dutch middle aged and all-cause mortality: a 25-year prospective study.

In the early 1950s, the blood pressure of 3901 Dutch civil servants and their spouses aged 40-65 years was measured in a general health survey. Isolated systolic hypertension (systolic pressure greater than 160 mmHg, diastolic pressure less than 90 mmHg) was observed in 6.3% of the women and 3.0% of the men. The prevalence increased with age and it was more common in women in all age groups. Using logistic regression, with adjustment for potential confounders (age, smoking, serum cholesterol, Quetelet index, alcohol consumption, haemoglobin level, pulse rate and diastolic blood pressure) the association of 15- and 25-year total mortality with isolated systolic hypertension was determined. Compared to normotensive people (systolic pressure less than or equal to 135 mmHg, diastolic pressure less than 90 mmHg), the risk of death from all causes was significantly higher for men with isolated systolic hypertension after 15 and 25 years of follow-up (odds ratio OR = 2.4, 95% confidence interval (CI) 1.2-4.8 and OR = 3.2, 95% CI 1.3-8.0). For women 15-years mortality risk was strongly associated with isolated systolic hypertension (OR = 3.7, 95% CI 1.4-9.7). The increased risk was less pronounced after 25 years of follow-up (OR = 1.7, 95% CI 0.96-3.0). Our results support those of other studies and indicate that isolated systolic hypertension is an important independent risk factor for all-cause mortality. Since isolated systolic hypertension may be an indicator for the early onset of ageing, it is important to study its determinants and to pay more attention to its diagnosis and treatment in middle-aged populations.