No abstract

The effects on lipid metabolism of bran and cellulose added to a low-cholesterol purified diet were studied in female obese Zucker rats. The obese Zucker rat was chosen for the experiment because of its sensitivity to dietary changes with regard to lipid metabolism. Cellulos, as well as bran, had an effect on lipid metabolism, which is expressed as an increase in the excretion of fecal bile acid and cholesterol and, in the case of bran feeding, as a decrease in liver cholesterol level and an increase of fecal fat excretion. The increased excretion rate of cholesterol and bile acids did not result in a reduction of the plasma cholesterol levels, which suggests a compensatory mechanism in the form of either an increase of hepatic cholesterol synthesis and/or changes within the body cholesterol pools. The increased excretion of fecal fat that occurred when bran was added to the diet, is not likely to influence cholesterol metabolism, since fecal fat excretion only appeared to form a small percentage of the total fat intake. Bran as well as cellulose caused a significant increase in fecal wet weight and a decrease in transit time. Though both cellulose and bran are capable of binding bile acid, cholesterol and/or fat, the intestinal transit time and the fecal bulk might also be a cause of increased steroid excretion. The fact that our results are inconsistent with those of some investigations described in the literature but in agreement with the findings of other workers, again stresses the primary need for a better chemical characterization of the various fiber sources.

Ringversuch zur Bestimmung von Vitamin D-MetaboUtenZusammenfassung: In einem Ringversuch wurde die Bestimmung der 25-Hydroxy-, 24,25-Dihydroxy-und 1,25-Dihydrpxy-Metabolite von Vitamin D in 6 Laboratorien der Niederlande überprüft. Drei verschiedene Serumproben und zwei verschiedene Standardlösungeri jedes Metaboliteri wurden untersucht. Für die Bestimmung in Serumproben wurden erhebliche Unterschiede zwischen den Laboratorien festgestellt. Die mittleren Variationskoeffizienten zwischen den Laboratorien für die Bestimmung der 25-Hydroxy-, 24,25-Dihydroxy-und 1,25-Dihydroxy-Metaboliten von Vitamin D in den drei Seren betrugen 48%, 38% und 28%. Die Bestimmung in den Standardlösungen aller The term vitamin D includes both Da and 1)3 derivatives. However, vitamin D 2 metabolite concentrations are assumed to be negligible.

No abstract

In a double-blind, placebo-controlled trial with 58 normotensive female students, the effect of oral-calcium supplementation (1500 mg Ca++/day for 6 wk) on diastolic and systolic blood pressure was studied while students were consuming a low-calcium diet (500 mg Ca++/day) by restricting the intake of dairy products. Results show that, in both the calcium- and placebo-supplemented groups, blood pressure values decreased slightly and no effect of oral-calcium supplementation on blood pressure could be demonstrated. In addition, at baseline neither systolic nor diastolic blood pressure correlated with habitual calcium intake. Diastolic but not systolic blood pressure correlated significantly with body mass index (r = 0.31, p = 0.01). It is concluded that oral-calcium supplementation for 6 wk does not influence blood pressure in young, healthy normotensive females consuming low-calcium diet.