摘要:

The dietary sugar of 15 young men was reduced from their habitual approximately 150 g/day to about 55 g/day. After 3 weeks, the concentration of oestradiol in their plasma fell by about 25%. Resumption of their habitual intake of sugar for 2 weeks restored the oestradiol concentration to its previous value. The results provide further evidence that dietary sugar can be one of the causes of coronary heart disease, and support the view that the underlying mechanism producing the disease is a disturbance in hormone balance.

ISSN:0250-6807    

DOI:10.1159/000177407

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The effect of heavy alcohol consumption on serum concentrations of vitamin E (α-tocopherol) and selenium was studied in 13 alcoholics and 19 control subjects. Ethanol intake during the year previous to the study was in the range from 22 to 354 g/day and from 0 to 16 g/day among the alcoholics and controls, respectively. Of the 13 alcoholics, 6 had a serum concentration of α-tocopherol below the lower limit of reference (14 µmol/l) and mean serum concentration of α-tocopherol was reduced by 37% as compared to controls (p < 0.002). Estimated dietary intake of α-tocopherol during the year previous to the study was approximately 40% lower for the alcoholics (p < 0.05). During hard-drinking periods the alcoholics had a markedly reduced intake of α-tocopherol as compared to moderate-drinking and abstinent periods. Mean serum concentration of selenium was significantly reduced in the alcoholics (1.2 ± 0.3 µmol/l) as compared to the controls (1.6 ± 0.2 µmol/l) (p < 0.002). The reduced serum levels of α-tocopherol and selenium may influence the maintenance of normal cell structure and function, and contribute to development of diseases frequently observed in

ISSN:0250-6807    

DOI:10.1159/000177408

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Possible methods of estimating residual volume for the prediction of body fat have been compared in young and healthy adults, with particular reference to the potential of a rapid helium equilibration method. In the first experiment, 5 women and 5 men performed nitrogen elimination, oxygen dilution and helium equilibration tests; scores for the helium test were higher than for the other two methods, but lay between the predictions made by Bass in 1964 and by Wilmore in 1969 and the values predicted by the equation of Goldman and Becklake in 1959. However, estimates of body density and body fat, based on residual volumes obtained from the prediction equations, did not differ significantly from those obtained directly by helium equilibration. A second experiment compared the helium and the oxygen techniques in 18 men and 18 women, with similar results. A final experiment compared the simple helium equilibration procedure with vital capacity and anthropometric predictions also suited to large scale determinations of body composition. It is concluded that the rapid helium equilibration procedure provides a fast and convenient procedure for the residual volume component of a body fat estimation. However, further study of the adequacy of equilibration is needed in older subjects and in patients with chronic chest disease.

ISSN:0250-6807    

DOI:10.1159/000177409

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Seasonal variations of blood lipids, which must be considered when performing long-term studies, could be partially due to dietary changes. In the present study, serum lipid parameters were measured each month for 1 year in nuns living in a monastery, whose diet was perfectly regular and controlled. The serum lipid variations observed consisted mainly of an increase in total cholesterol, low-density lipoproteins and apolipoprotein B in autumn and spring and an increase in high-density lipoprotein cholesterol in winter, whereas apoli-poproteins A-I and A-II showed a marked increase in summer and at the beginning of autumn. These variations were probably induced by factors directly related to seasonal rhythm and not to dietary factors or physical exercise. Lastly, the influence of sex hormones seems to be very minor, as postmenopausal women (one-third of the persons) had an identical variation in their lipid parameters, to that observed in the whole group.

ISSN:0250-6807    

DOI:10.1159/000177410

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Rat hepatic microsomal mixed-function oxidase activities were not significantly affected by vitamin A deficiency. Similarly cytosolic glutathione S-transferase and glutathione reductase activities as well as total glutathione levels were unaffected by the vitamin A status. Induction of the mixed-function oxidases by 3-methylcholanthrene or phenobarbi-tone was independent of the vitamin A status. No significant differences in microsomal chemiluminescence, before and following challenge with tertiary butyl hydroperoxide, were evident between the vitamin-A-deficient animals and those maintained on vitamin-A-supplemented diets. The present findings indicate that the protective action of vitamin A against chemical carcinogens is unlikely to involve modulation of the enzyme systems responsible for their metabolism.

ISSN:0250-6807    

DOI:10.1159/000177411

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

This report describes whether a complete exchange of soy protein isolate for casein affects serum lipid or lipoprotein levels. For this purpose, 10 adult minipigs underwent two 6-week crossover experiments, one with 11 and one with 22 weight% protein in a western-style diet. Cholesterol levels were 2.02 ± 0.06 and 1.98 ± 0.04 mmol/l with casein and soy, respectively (22 weight%) and 2.08 ± 0.06 and 2.04 ± 0.05 mmol/l, respectively (11 weight%). There was a significant rise of high-density lipoprotein cholesterol by the lower protein intake, both with casein and soy. In all experiments nitrogen balance was positive. Soy feeding was accompanied by a significant rise of fecal bacterial protein excretion, as calculated from diaminopimelic acid. In summary, no statistically significant difference of plasma or low-density lipoprotein cholesterol levels were observed, neither due to the kind nor to the amount of dietary prot

ISSN:0250-6807    

DOI:10.1159/000177412

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The influence of dietary vitamin E on the composition of essential fatty acids in rat tissue and plasma lipids as well as serum thromboxane B2 was studied. Diets containing deficient (0mg/kg diet), adequate (100mg/kg) or supplemental (1,000 mg/kg) vitamin E were fed to young male rats for 10 weeks. The ratio of dihomo-γ-linolenic acid to arachidonic acid in phospholipids of plasma, liver, and testes was increased in vitamin-E-supplemented rats. Serum thromboxane B2 was increased in vitamin-E-deficient rats. The data support a role for vitamin E in affecting both metabolism of long chain fatty acids, i.e. dihomo-γ-linolenic acid, and conversion of arachidonic acid to thromboxane A2

ISSN:0250-6807    

DOI:10.1159/000177413

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

In adult male rats fed a non-purified diet supplemented with 5 % sodium propionate, plasma cholesterol concentrations were significantly depressed. Although liver cholesterol was increased by feeding propionate, rates of hepatic cholesterol and fatty acid synthesis were unchanged. Tissue concentrations and rates of synthesis of cholesterol were also unaffected by dietary propionate in stomach, small intestine and caecum. Concentrations of propionate in hepatic portal venous plasma were raised by feeding the supplemented diet but the increase was low in comparison to the dietary intake. Examination of the gut contents revealed concentrations of total volatile fatty acids (VFA) of 19 µmol/ml in the stomach contents of control rats and 148 µmol/ml (of which propionate contributed 116 µmol/ml) in those fed the supplemented diet. Duodenal and ileal concentrations of VFA were very low and were only slightly raised in the propionate-fed rats while caecal VFA were the same in both groups with a combined mean of 159 µmol/ml. These data indicate that in the rat, the absorption of dietary propionate appears to occur in the stomach. In pigs fed a standard ration hepatic portal venous VFA remained low for the first 4 h after feeding but then rose with the onset of large bowel fermentation. Feeding the diet supplemented with propionate caused hepatic portal venous plasma concentrations to rise by approximately 0.4 µmol/ml. This increase was apparent 30 min after feeding and was sustained for 3 h but subsequently there was no difference to controls. As in the rat, the absorption of dietary propionate appeared to occur in the upper gastrointestinal tract. The transport of propionate via the porcine hepatic portal vein also appeared insufficient to account for the dietary intake and suggests metabolism of the acid by the upper gastrointestinal tract. Further studies with perfused livers from fed rats indicated that propionate at a concentration of 1 µmol/ml did not alter cholesterol synthesis but that inhibition occurred at 18 µmol of propionate/ml. It appears that a redistribution of cholesterol from the plasma to the liver, rather than inhibition of hepatic and intestinal cholesterol synthesis, is responsible for the hypocholesterolaemic effects of dietary propionate. Because the absorption and transport of dietary propionate appears to follow a time course which differs considerably to that of the acid produced by the large bowel microflora, we conclude also that VFA produced by such fermentation would not seem to be responsible for the hypocholesterolaemic effects of certain water-soluble plant

ISSN:0250-6807    

DOI:10.1159/000177414

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The vitamin D3 metabolites 1α,24R,25- and 1α,25S,26-trihydroxy vitamin D3 and their combinations with 1α,25-dihydroxy vitamin D3 were tested for antirachitic activity in rats, chicken and Japanese quails. The trihydroxylated compounds were found to increase the activity of 1α,25-dihydroxy vitamin D3. Since this synergistic effect is restricted to calcium absorption and bone formation while bone calcium mobilization is unchanged, the combined administration might improve calcium balance. These findings raise the possibility of a more efficient therapy of vitamin D-dependent diseases with limited amounts of 1α,25-dihydroxy vitamin D3

ISSN:0250-6807    

DOI:10.1159/000177415

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:0250-6807    

DOI:10.1159/000177416

出版商:S. Karger AG    

年代:1988

数据来源: Karger