摘要:

Vitamin C functions as a regulator of the catabolism of cholesterol to bile acids in the guinea pig and has been demonstrated to be an important factor in lipid regulation of the guinea pig, rabbit and rat. Correlation studies in humans have shown an inverse relationship between vitamin C intake and cardiovascular disease mortality. Observational and experimental studies in humans have yielded inconsistent results, but taken together indicate that for individuals with high total cholesterol concentrations,≥5.20 mmol/L (200 mg/dl) and less than full tissue saturation, increasing the concentration of vitamin C may have a salutary effect on total cholesterol. Vitamin C’s effect on promoting the production and inhibiting the degradation of prostacyclin is reviewed, as are implications of these findings regarding thrombosis and atherogenesis. Evidence indicative of a protective effect on lipid peroxidation by vitamin C is examined. Analysis of the literature regarding groups at high risk for coronary heart disease reveals that men, the elderly, smokers, diabetics, hypertensives and perhaps oral estrogen-containing contraceptive users have lowered plasma vitamin C levels. Evidence linking vitamin C to human cardiovascular disease is largely circumstantial, but taken in total, is suggestive of an association. Further examination of the relationship between vitamin C and cardiovascular disease is warranted.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098232

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

The effect of almonds as part of a low saturated fat, low cholesterol, high-fiber diet was studied in 26 adults (13 men, 13 women). The baseline diet was modified in a similar way for all subjects by limiting meat, fatty fish, high-fat milk products, eggs, and saturated fat. Grains, beans, vegetables, fruit, and low-fat milk products were the foundation of the diet. During the almond diet period, raw almonds (100 mg/day) supplied 34 g/day of monounsaturated fatty acid (MUFA), 12 g/day of polyunsaturated fatty acid, and 6 g/day of saturated fatty acid. Almond oil was the only oil allowed for food preparation. There was a rapid and sustained reduction in low-density lipoprotein cholesterol without changes in high-density lipoprotein cholesterol. This was reflected in a total plasma cholesterol decrease from (means±SEM) 235±5.0 at baseline to 215±5.0 at 3 weeks, and to 214±5.0 mg/dl at 9 weeks (p>0.001). When the consumption of nuts high in MUFA increases the fat content of the diet, reduction rather than elevation of plasma cholesterol has to be expected, possibly due to the MUFA content of these nuts.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098233

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Prevention and regression of induced atherosclerosis by d-α-tocopherol was investigated in 24 maleM. fascicularis. One group received a basal diet, while three others consumed an atherogenic diet. Two of the latter groups also received tocopherol, one at the onset of the study (prevention) and the other after atherosclerosis was established by ultrasound evaluation (regression). Atherosclerosis was monitored over a 36-month period by duplex ultrasound imaging of the common carotid arteries. At termination, 24 arterial sites were examined for histopathology. In those animals receiving an atherogenic diet, mean percent ultrasound stenosis at 36 months posttreatment was lower in the tocopherol-supplemented groups (61 and 18%) than in the unsupplemented group (87%). Plasma tocopherol concentration was negatively correlated with percent ultrasound stenosis (p<0.002). Percent stenosis in the regression group decreased from 33 to 8% (p<0.05) 8 months after tocopherol supplementation. Although not consistently significant, histopathological changes were greater in untreated compared to treated animals. These results, if confirmed, indicate that d-α-tocopherol may be prophylactically and therapeutically effective in atherosclerosis.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098234

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Diet has been linked to cardiovascular disease risk by its influence on low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and blood pressure (BP). Recent evidence suggests that vitamin C may play a role in regulation of cholesterol and BP. The cross-sectional relationships of plasma ascorbic acid (PAA) with cholesterol and BP are described in three Boston area samples: 1) 249 males and 447 females (aged 60–100 years), 2) 100 Chinese-American males and 159 Chinese-American females (aged 60–96 years), and 3) 225 male and 192 female participants (aged 20–60 years) in a randomized field trial of vitamin C supplementation. Results indicate 3.7–9.5% higher levels of HDL-C, 4.1% lower levels of LDL-C, and 1.9–5.5% lower levels of BP with each 30µmol/L increment in PAA. These relationships may be stronger at lower levels of PAA.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098235

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

The purpose of this study was to determine the accuracy of standard methods for estimating body composition in individuals who have undergone substantial and rapid weight loss. Subjects included 14 participants in a rapid weight reduction program using a very low-calorie diet, and 14 individuals of normal body composition matched with the obese group on the basis of gender, age, and height. Bioelectrical impedance (BI) and skinfold-derived estimates of relative body fat were compared with hydrostatic weighing in both groups. On the basis of mean values, standard errors of estimate (SEE) and simple correlations, none of the skinfold equations or the BI procedure were very accurate in the prediction of body fat in the group of weight-reduced obese patients. The Durnin-Rahaman (D-R) and Durnin-Womersley (D-W) equations were not significantly different from the hydrostatically determined values; however, correlations were low (r = 0.69 and 0.60). The Jackson-Pollock (J-P) equations and BI technique had high correlations (r = 0.78 and 0.89), but were significantly different from hydrostatic weighing. SEE for all equations and BI were high (>4.5%). The control group was best predicted by the J-P equation (r = 0.88, SEE 3.5%, mean value of 21.2±4.3 vs 22.4±6.2%). BI and the D-R equation were also reasonably accurate. We conclude that additional research will be necessary to identify a predictive equation using skinfolds or BI that will provide more accurate estimates of relative body fat in individuals who have undergone substantial weight reduction in a relatively short period of time.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098236

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Strength changes, induced by very low-calorie diet (VLCD, 520 kcal/day) alone and in combination with exercise, were determined in 109 severely obese females (46.8±4.69% fat). Experimental treatments included VLCD alone (LC, n = 40), VLCD with endurance exercise (EE, n = 23), VLCD with endurance exercise and resistance strength training (EERST, n = 23), and VLCD with resistance strength training (RST, n = 23). All subjects participated in the study for 90 days while EE, EERST, and RST exercised four times/week according to specified schedules. Results indicated significant differences for the change scores (baseline to 90 days) for bench press, knee flexion, upper body and lower body composite strength scores between RST and all other groups. RST was the only treatment that increased upper and lower body strength. No differences between groups were found for body mass losses, decreases in percent fat and fat mass. In contrast, these variables showed significant change scores for all groups. Decreases in fat-free mass (FFM) were 5.18±3.40 kg, 4.79±4.15 kg (p = 0.001), 4.64±4.23 kg, and 3.26±2.67 kg for EE, LC, RST, and EERST, respectively. These data suggest that the combination of resistance strength training and VLCD increases strength despite a loss of FFM. However, endurance exercise and VLCD do not seem to affect body mass loss or FFM lossper se.Moreover, it seems that these increases in strength may represent a training effect which might imply improved central neuromuscular function rather than muscular hypertrophy since FFM decreased in all groups.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098237

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

This was a 4-week randomized, placebo-controlled double-blind study to assess augmentation of open tricyclic antidepressant treatment with 10 mg each of vitamins B1, B2, and B6 in 14 geriatric inpatients with depression. The active vitamin group demonstrated significantly better B2 and B6 status on enzyme activity coefficients and trends toward greater improvement in scores on ratings of depression and cognitive function, as well as in serum nortriptyline levels compared with placebo-treated subjects (Ss). Without specific supplementation, B12 levels increased in Ss receiving B1/B2/B6 and decreased in placebo Ss. These findings offer preliminary support for further investigation of B complex vitamin augmentation in the treatment of geriatric depression.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098238

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

A retrospective analysis of osteoporotic patient records was conducted to evaluate the effect of supplemental calcium (Ca) on urinary and serum Ca. Forty-seven patients composed the Ca-supplemented group and 17 patients the nonsupplemented group. Serum Ca values (mean±SD) were 9.3±0.3 and 9.4±0.4 mg/dl in the nonsupplemented and supplemented groups, respectively. Daily urinary Ca was 137±88 and 162±89 mg, respectively. Each group had similar concentrations of serum phosphorus, albumin and creatinine. Data from the Ca-supplemented group were divided into low and high Ca intake. In the low intake group (1000 mg/day), the values were 9.5±0.5 and 160±90, respectively. Seventeen and 36% of nonsupplemented and supplemented patients used estrogen, respectively. No significant effects of estrogen therapy were observed on serum or urinary Ca in either group. More detailed analysis of five patients was undertaken to evaluate the combined effect of supplemental vitamin D (ergocalciferol or calcitriol) and Ca on urinary Ca output. Baseline urinary Ca was 33±19 mg with an average daily Ca supplement of 1160 mg. After 4–8 weeks of supplementation with Ca and vitamin D, urinary Ca increased to only 68±33 mg. We conclude that supplemental Ca does not appear to cause a significant increase in urinary Ca and that added vitamin D has little effect on elevating urinary Ca in some older women. At the clinical level, use of Ca supplements will probably not lead to increased prevalence of hypercalciuria or nephrolithiasis; however, large variations among patients must be considered in the clinical use of Ca supplements.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098239

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

In the present study we evaluated lactose malabsorption (LM) after ingestion of three dairy products in 53 healthy institutionalized elderly people. A preliminary screening with milk (250 ml, 11 g lactose) was carried out to select the LM subjects using the H2 breath test. The effect of consuming an equivalent amount of lactose contained in yogurt and fermented-then-pasteurized milk (FPM) was then assessed in LM subjects. Results indicated that 36% of the elderly population studied was considered as LM and that breath H2 excretion was significantly higher after ingestion of milk than after ingestion of yogurt. This beneficial effect was partially eliminated when FPM was tested. Moreover, breath H2 excretion was significantly higher (p<0.05) 3 hours after ingestion of FPM compared to the normal yogurt. These results demonstrate a high prevalence of LM in the elderly and confirm the positive effect of yogurt on lactose absorption, whereas pasteurized yogurt did not cause the same effect.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098240

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Renewed interest in the antihistamine action of ascorbic acid has emerged with the recently recognized immunosuppressive role of histamine. We examined the antihistamine effect of acute and chronic vitamin C (VC) administration and its effect on neutrophil chemotaxis in healthy men and women. In the chronic study, 10 subjects ingested a placebo during weeks 1, 2, 5 and 6, and 2 g/day of VC during weeks 3 and 4. Fasting blood samples were collected after the initial 2-week period (baseline) and at the end of weeks 4 and 6. Plasma ascorbate rose significantly following VC administration compared to baseline and withdrawal values. Neutrophil chemotaxis rose 19% (NS) during VC administration, and fell 30% after VC withdrawal, but these changes were not correlated to plasma ascorbate levels (r = 0.01). Chemotaxis was inversely correlated to blood histamine (r =−0.32, p = 0.045), and, compared to baseline and withdrawal values, histamine levels were depressed 38% following VC supplementation. Blood histamine and neutrophil chemotaxis did not change 4 hours following a single 2 g dose of ascorbic acid, although plasma ascorbate rose 150%. These data indicate that VC may indirectly enhance chemotaxis by detoxifying histamine in vivo.

ISSN:0731-5724    

DOI:10.1080/07315724.1992.12098241

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor