ISSN:0731-5724    

DOI:10.1080/07315724.1996.10738015

出版商:Routledge    

年代:1996

数据来源: Taylor

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718558

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

In the past 5 years, four prospective, epidemiologic studies of“weight cycling”found that mortality is higher for persons with unstable body weight than for persons whose body weight is relatively stable [1-3,5]. These findings have generated considerable interest and controversy in both the scientific community and the lay press because of the belief that the weight fluctuations were caused by intentional weight loss. None of these studies, however, collected information that would indicate whether the weight changes were intentional or unintentional. This review examines the reasons given by the authors of these studies to support the inference that intentional weight loss caused the increase in mortality. The authors acknowledged that weight loss can be caused by preexisting illness, and they usually made efforts to control for the confounding effects of illness in their analyses. However, they generally concluded that the weight fluctuations resulted from unsuccessful dieting, but no data were presented on the incidence or causes of weight fluctuation in the populations from which the samples were drawn. In none of the studies did the authors recommend that obese persons stop trying to lose weight. The reader is cautioned to await further studies in which intentionality of weight loss is directly assessed before concluding that dieting to reduce weight increases the risk of mortality.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718559

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

There is an increased requirement for nutrients in normal pregnancy, not only due to increased demand, but also increased loss. There is also an increased insulin-resistant state during pregnancy mediated by the placental anti-insulin hormones estrogen, progesterone, human somatomammotropin; the pituitary hormone prolactin; and the adrenal hormone, cortisol. If the maternal pancreas cannot increase production of insulin of sustain normoglycemia despite these anti-insulin hormones, gestational diabetes occurs. Gestational diabetes is associated with excessive nutrient losses due to glycosuria. Specific nutrient deficiencies of chromium, magnesium, potassium and pyridoxine may potentiate the tendency towards hyperglycemia in gestational diabetic women because each of these four deficiencies causes impairment of pancreatic insulin production. This review describes the pathophysiology of the hyperglycemia and the nutrient loss in gestational diabetes and further postulates the mechanism whereby vitamin/mineral supplementation may be useful to prevent or ameliorate pregnancy-related glucose intolerance.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718560

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

Hypertension, a major public health problem, becomes more prevalent during aging. Epidemiological studies suggest that environmental factors such as nutrition may play a major role in blood pressure (BP) regulation. It is generally accepted that obesity and sodium/alcohol consumption are important factors, and many believe that calcium, magnesium and potassium consumption are regulatory as well. Less emphasis has been placed on whether macronutrients influence blood pressure significantly. This review focused on the ability of excess calories and consumption of carbohydrates, fats, and proteins to regulate blood pressure.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718561

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

To determine: 1) the concentrations and fractions of serum ionized magnesium (IMg2+) in normal antenatal patients and 2) whether they are altered by concentrations of other cations and serum proteins.A cross sectional study design.An urban community hospital obstetrics clinic.144 normal antenatal patients divided into four gestational age groups: (1) 25 at 6 to 12 weeks, (2) 55 at 13 to 20 weeks, (3) 37 at 21 to 27 weeks, and (4) 27 at 28 to 38 weeks.Utilizing ion selective electrodes, we determined concentrations and fractions of ionized magnesium, concentrations of ionized calcium, sodium, and potassium, and the pH level in the venous serum of the patients. Total magnesium (TMg), total calcium, total protein, albumin, and inorganic phosphorus were measured.The mean concentrations and fractions were compared between the groups. Correlations between concentrations or fractions of Mg and concentrations of the other cations or proteins were determined.All values are means+/−SD. IMg2+ concentrations are 0.53+/−0.03 mmol/L in the first trimester and are lowest (0.49+/−0.05 mmol/L, p<0.001) by the third trimester. The percent of ionized magnesium remains at approximately 66% in each antenatal group. Although mean Mg concentrations fall with advancing gestational age, the main determinant of the IMg2+ concentration in an individual patient is her TMg concentration.IMg2+ concentrations and fractions remain within a very narrow range during pregnancy and are minimally affected by physiologic hemodilution. We hypothesize that mobilization of intracellular or bone stores of magnesium helps maintain serum concentrations, thus placing a stress on magnesium balance.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718562

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

Vitamin E is a physiological antioxidant and protects cell membranes from oxidative damage. This study has determined whether vitamin E level in RBC of newborns has any relationship with its level in their mothers. We have also examined levels of vitamin E and vitamin E-quinone, an oxidized product of vitamin E, in paired samples of red blood cells (RBC) and plasma of newborns and their mothers.Blood was collected from 26 mothers and their full-term placental cords at delivery. Vitamin E and vitamin E-quinone levels were determined in RBC and plasma by HPLC.Newborn-plasma had significantly lower vitamin E levels compared with maternal-plasma both when expressed as nmole/ml (5.5+/−0.4 vs 26.1+/−1.1, p = 0.0001) or nmole/mumole total lipids (1.9+/−0.1 vs 2.6+/−0.1, p = 0.0001). Vitamin E level in the newborn-RBC was similar to that of maternal-RBC when expressed as nmole/ml packed cells (2.77+/−0.14 vs 2.95+/−0.13), but was significantly lower when expressed as nmole/mumole total lipids (0.56+/−0.03 vs 0.64+/−0.04, p = 0.03) from that of maternal-RBC. Vitamin E-quinone levels are significantly elevated in newborns compared with their mothers both in RBC (29.4+/−2.1 vs 24.1+/−1.2, p = 0.04) and plasma (39.9+/−5.3 vs 25.3+/−4.2, p = 0.006) when expressed as nmole/mmole total lipids but not when expressed as nmole/ml. There was a significant correlation of vitamin E between newborn-plasma and newborn-RBC (r = 0.65, p = 0.0002 for nmole per ml packed RBC;r = 0.63, p = 0.0007 for nmole per mumole total lipids). The relationship between maternal plasma and newborn plasma was significant when vitamin E was normalized with nmole/mumole total lipid (r = 0.54, p = 0.007 but not when expressed as nmole/ml (r = 0.09, p = 0.64). However, vitamin E in the RBC of maternal and newborn had significant correlation when expressed as per ml packed cells (r = 0.61, p = 0.001) and per total lipid (r = 0.46, p = 0.02). There was no relationship of vitamin E-quinone levels between RBC and plasma of newborns and their mothers.Elevated blood levels of vitamin E-quinone suggest increased oxidative stress and utilization of vitamin E in newborns compared to their mothers. Because vitamin E levels in RBC of newborns are lower and significantly related to vitamin E levels in RBC of their mothers, an increase in vitamin E supplementation to mothers during pregnancy may increase vitamin E levels in the newborn and help impede the effect of extrauterine oxygen toxicity.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718563

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

To study the relationships between the essential fatty acid (EFA) composition of maternal diet, maternal EFA status and the EFA status of healthy newborn infants.A prospective longitudinal study was performed in which 176 pregnant women completed a food frequency questionnaire (FFQ) before 13, at 22, and at 32 weeks of gestation, so that changes in nutrient intake throughout pregnancy could be recorded. Around 22 weeks, a dietary history was performed and a maternal blood sample was collected. Immediately after delivery, a blood sample from the umbilical vein and a piece of the umbilical cord were collected. Fatty acid compositions were determined for phospholipids (PLs) isolated from maternal and umbilical plasma and from umbilical vein and artery vessel walls.No significant differences in the mean daily intake of total fat, saturated fat, mono-unsaturated fat, polyunsaturated fat and linoleic acid (18:2(n-6), LA) were observed between the three trimesters. Maternal LA intake was positively associated with LA levels in maternal and umbilical plasma and negatively associated with 20:3(n-9), 18:3(n-3), 20:4(n-3) and 22:5(n-3) levels in maternal plasma, with 20:5(n-3) levels in umbilical plasma and with 22:6(n-3) levels in umbilical vein vessel walls. Significant positive correlations for almost all (n-6) and (n-3) fatty acids were observed between maternal and umbilical plasma levels.The maternal dietary fat composition appears to be consistent during pregnancy. A high maternal LA intake may have a lowering effect on the maternal as well as on the neonatal (n-3) fatty acid status. Finally, neonatal EFA status is strongly related to maternal EFA status.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718564

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

We developed, pilot-tested, and field-applied a stages of change questionnaire regarding fruit and vegetable (F&V) consumption among fourth- and fifth-grade students.The design included cross-sectional assessment of internal consistency and construct validity, and 2-week and 7-week longitudinal assessment of test-retest reliability. Subjects included 134 students from one school for pilot-testing and 252 from two schools for field application. Thirty-two questions from McConnaughy et al's stages of change questionnaire were adapted and pilot-tested; minor revisions were made for field application. Statistical analyses included principal components analysis to identify subscales; cluster analysis to identify subgroups within students; Cronbach's alpha coefficient to assess internal consistencies; Pearson product-moment correlations to assess test-retest reliabilities; and oneway ANOVA's by F&V stages of change clusters with actual F&V consumption, F&V self-efficacy subscales, F&V preferences, and F&V outcome expectations subscales to determine construct validity.Principal components analysis from the field application indicated two subscales (precontemplation and beyond precontemplation) accounting for 39.5% of variance. Cluster analysis indicated 6 interpretable clusters; 2 (n = 63) provided responses inconsistent with the stages of change theory and 4 (n = 189) provided responses consistent with the theory. Internal consistencies and test-retest reliabilities were acceptable. Students in the“beyond precontemplation”clusters had higher levels of self-efficacy and outcome expectations regarding eating F&V.Measuring stages of change other than the precontemplation stage in F&V consumption among elementary school children is problematic. Perhaps the theoretical concept does not apply to children, or elementary school children lack the ability to comprehend the questions measuring the concept, or the approach used was not entirely appropriate.

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718565

出版商:Routledge    

年代:1996

数据来源: Taylor

摘要:

The objective of this study was to gain more knowledge about the breakfast habits of different groups of elderly people and to investigate the differences in breakfast habits between overweight and normal weight elderly subjects.A study was made of the food preferences, dietary habits and the intake of energy and nutrients at breakfast in a group of 122 elderly Spanish people (65 men and 57 women) aged 75.7+/−8.7 years. Study participants were divided into two groups: overweight and obese subjects (O) with a body mass index (BMI)>or=25 kg/m2 (58% of the population), and normal weight subjects (NW) with a BMIor=80 years of age (Y) and

ISSN:0731-5724    

DOI:10.1080/07315724.1996.10718566

出版商:Routledge    

年代:1996

数据来源: Taylor