摘要:

From a population of singleton pregnancies, 152 overweight women (greater than 110% of standard) were matched with normal weight women (95-110%) for age, height, parity, race, and smoking habits. Comparisons were made of initial weight (weight at the first prenatal visit) and gestational weight gain and pregnancy outcome. Mean birth weights and gestational ages of infants of normal and overweight women were not significantly different. For normal weight women birth weight increased significantly as height, initial weight, and body mas index increased (p less than 0.01), but no such relationship existed for overweight women. The lack of effect of initial weight on birth weight in overweight women is attributable, in part, to the significantly less gestational weight gains of these mothers (6.3 kg vs 8.2 kg). When normal and overweight gravida had gestational weight gains of less than 7 kg, offspring of overweight mothers were significantly heavier. Gestational weight gain was positively correlated with birth weight for both normal (p less than 0.0001) and overweight women (p less than 0.001). Within the overweight and normal weight groups, smokers had lower initial weights and gestational weight gains than nonsmokers. Offspring of normal weight smokers had a mean birth weight 232 g less than that of nonsmokers (p less than 0.01). The difference in birth weight between overweight smokers and nonsmokers (135 g) was not statistically significant. While there is substantial data to support a weight gain of 10-12 kg in normal weight gravida, it would appear that a gain of approximately 7 kg in overweight middle class women does not impair fetal growth as measured by birth weight.(ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720336

出版商:Routledge    

年代:1989

数据来源: Taylor

摘要:

This study was performed to determine (1) the normal serum response to a single oral dose of beta-carotene (BC), (2) the effect of meal timing and serum response to meal lipids on serum BC, (3) the effect of administered BC on other serum carotenoids and retinoids, and (4) the relationship of body composition to serum BC response. Subjects consumed one BC dose with a liquid 500 kcal BC-free diet; fasting and hourly venous blood was collected for 8 hours and again at 24 hours. A second liquid BC-free meal was consumed 4 hours post-dosing; this midday meal was omitted in some subjects. Serum BC levels rose and peaked initially at 5 hours, but continued to be absorbed in most subjects, remaining significantly elevated at 24 hours as compared to baseline values (p less than 0.001), independent of BC dose. The area under the BC absorption curve (8-hr AUC) increased linearly with BC dose and correlated positively with peak serum triglycerides (TG) after a meal (n = 26 tests, r = 0.56, p less than 0.003). Omission of the midday meal significantly delayed the initial BC peak to 7 hours (p less than 0.0004). Serum levels of retinol, alpha-carotene, cryptoxanthin, lycopene, and lutein remained unchanged. Serum retinyl esters did not rise in all subjects following BC intake; when it did, retinyl esters rose and peaked concomitantly with BC, but declined within 8 hours. There was no correlation between the initial serum BC, peak BC, 24-hr BC, 8-hr AUC, or peak serum TG and the percentage of body fat. We conclude that: (1) the timing of the serum response to oral BC is independent of dose, (2) the serum BC response is greater in those with a greater serum triglyceride response to meal lipids, (3) BC at the doses given does not alter the levels of other serum carotenoids, and (4) there is no correlation between the serum BC parameters measured and adiposity.

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720337

出版商:Routledge    

年代:1989

数据来源: Taylor

摘要:

There is widespread belief among athletes that special nutritional practices–in particular high-protein diets–will enhance their achievements in competition. Supplementation with vitamins, especially vitamin C, is equally popular. But because genetic predisposition, hard physical training and psychological factors play a most important role in determining performance, and because any potential difference in achievement will be small, it is almost impossible to obtain scientific evidence of a beneficial effect of a particular nutrient. There have been many investigations during the past four decades of the potential effect of high-dose vitamin C supplementation on physical performance. The variables used have included maximum oxygen uptake, blood lactic acid levels, and heart rate after exercise, and in some cases performance was assessed in competitive events. The results have been equivocal: Most studies could not demonstrate an effect. On the other hand, a suboptimal vitamin C status results in an impaired working capacity which can be normalized by restoring vitamin C body pools. Athletes, who follow irrational, unhealthy eating patterns often not including vitamin-C-containing fruit and vegetables, are in need of nutrition education.

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720338

出版商:Routledge    

年代:1989

数据来源: Taylor

摘要:

Maintenance of vitamin A stores in the body is dependent on a number of basic metabolic processes. These processes, such as protein and carbohydrate metabolism, are disrupted in acute starvation, and, as a result, alterations in vitamin A status may result. We investigated this possibility in 8-week-old Sprague-Dawley male rats. The rats were starved for 24, 48, and 72 hr but had free access to water. At 24 hours of starvation, the plasma retinol concentration was depressed, but not significantly so. After 48 and 72 hours of starvation, however, the plasma retinol concentration decreased to less than half of the control values (61 +/−4 vs 124 +/−12 nmol/dl at 72 hours, mean +/−SEM, (p less than 0.005). The hepatic retinoid (retinyl esters + retinol) concentration (nmol/g liver) was increased at 24 and 48 hours of starvation compared to controls (p less than 0.05), and by 72 hours the concentration was 56% greater in starved rats than in fed controls (p less than 0.001). The total hepatic retinoid content (mumol/total liver) was decreased moderately at all periods of starvation compared to controls (p less than 0.05). In both starved and fed animals, the total hepatic content per 100 g body weight, a measure of total vitamin A reserves, was statistically the same. These results demonstrate that acute starvation in rats alters the vitamin A equilibrium between the plasma and hepatic stores without affecting the overall vitamin A reserves.(ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720339

出版商:Routledge    

年代:1989

数据来源: Taylor

摘要:

Dietary folates exist as pteroylpolyglutamates (PteGlun) that undergo hydrolysis to pteroylmonoglutamate (PteGlu) forms during the process of intestinal absorption. Using the technique of jejunal perfusion of separately labeled folates, our laboratory has demonstrated that hydrolysis of PteGlun occurs on the surface of the jejunum and is a prerequisite for folate absorption. An intestinal brush border pteroylpolyglutamate hydrolase (BB-PPH) has been identified in human and pig jejunum with characteristics that are distinct from those of an intracellular hydrolase (IC-PPH). Functional parallels of BB-PPH with in vivo hydrolysis of PteGlun in human and pig intestine and the clinical responsiveness of BB-PPH to different disease states indicate that this enzyme plays the major physiological role in folate absorption. Folate malabsorption is found in diseases which affect the jejunal mucosa and in response to various drugs. In most of these clinical conditions, folate malabsorption results from suppression of both of the processes of hydrolysis of PteGlun and jejunal uptake of PteGlu. Ongoing studies in miniature pigs are aimed at definition of the sequence of development of folate malabsorption in chronic alcoholism.

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720340

出版商:Routledge    

年代:1989

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10720341

出版商:Routledge    

年代:1989

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10738132

出版商:Routledge    

年代:1989

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10738134

出版商:Routledge    

年代:1989

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10738135

出版商:Routledge    

年代:1989

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1989.10738136

出版商:Routledge    

年代:1989

数据来源: Taylor