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Biomedical subjects

S Margen

Publications and source records attributed to S Margen.

At least 19 recordsLinked to original sources
PubMed1993

Polysymptomatic syndromes and autonomic reactivity to nonfood stressors in individuals with self-reported adverse food reactions.

This study compared symptom reports and cardiovascular reactivity of a group of 24 individuals recruited from the community who reported a cognitive or emotional symptom caused by at least one food (food-sensitivity reporters, FSR) vs those of 15 controls (C) without a history of food, chemical, drug, or inhalant sensitivities. The main findings were: 1) FSR indicated sensitivities not only to foods, but also to environmental chemicals, drugs, and natural inhalants, as well as significantly more symptoms than C in multiple systems; 2) more FSR than C noted recent state depression and anxiety, as well as higher trait anxiety on the Bendig form of the Taylor Manifest Anxiety Scale; 3) however, on multiple regression analysis, not only depression, but also the number of sensitivities (foods, chemicals, drugs, inhalants), accounted for part of the variance in total number of symptoms (38 and 17%, respectively), whereas none of the affective measures accounted for any of the variance in total number of sensitivities over all subjects; 4) after controlling for depression and anxiety, FSR still showed a trend toward poorer performance on a timed mental arithmetic task (p = 0.16); and 5) FSR and C showed opposite patterns of heart rate change to two different stressful tasks (mental arithmetic and isometric exercise) (group by task interaction, p < 0.05). The data are discussed in terms of a time-dependent sensitization (TDS) process that predicts a cross-sensitizing and cross-reactive role for xenobiotic agents (e.g., foods, chemicals, drugs, and inhalants) and for salient psychological stress in the expression of psychophysiological dysfunctions of FSR. As in other chronically ill populations, negative affect in food-sensitive individuals may explain greater symptom reporting, but not necessarily account for the illness itself. For either a food or a psychological stimulus to begin to elicit sensitized responses, e.g., marked physiological differences from C, FSR may require multiple, intermittent exposures spaced over 5-28 days rather than on only 1 day.

Adult↗
PubMed1992

Iron nutrition does not account for the hemoglobin differences between blacks and whites.

Many researchers have reported lower hemoglobin concentrations in blacks than in whites, but the reason for this difference is unknown. Data for 2515 persons (in 3-12 y and 18-45 y age groups) from the Second National Health and Nutrition Examination Survey (NHANES II) were evaluated to investigate the roles of iron intake and biochemical iron status indicators in explaining black and white differences in hemoglobin concentration. Dietary iron intake was estimated from one 24-h food recall, and hemoglobin, serum ferritin, transferrin saturation and erythrocyte protoporphyrin were measured by standard laboratory methods. Hemoglobin levels were substantially lower in black children (120.3 g/L) than in white children (126.8 g/L). Hemoglobin concentrations were also lower in black women (128.4 g/L) than in white women (133.9 g/L), and in black men (144.8 g/L) than in white men (153.2 g/L). Blacks had lower hemoglobin concentration than whites at most levels of dietary iron intake, serum ferritin, transferrin saturation and erythrocyte protoporphyrin. Despite their lower hemoglobin levels, blacks had higher serum ferritin levels than whites. These results suggest that the difference in hemoglobin concentrations between blacks and whites in the United States is the result of factors other than iron intake and iron status. More specific investigations of both the genetic and environmental determinants of iron utilization in blacks are needed.

Adult↗
PubMed1987

Postprandial thermogenesis at rest and during exercise in elderly men ingesting two levels of protein.

Seven elderly male subjects (69 +/- 3 yr, 67.8 +/- 9.2 kg, 24.5 +/- 3.6% body fat) lived for 12 consecutive weeks in a metabolic unit and maintained their weight with two different diets fed for 6 weeks each: Diet A, consisted of their habitual protein intake as determined on the outside by a dietary record (mean +/- SD, 1.12 +/- 0.22 g/kg d). Diet B was an isocaloric diet with reduced protein intake (70 mgN/kg d, i.e., 0.44 g protein/kg d) at the level of physiological protein requirement [7]. After 3 weeks on each diet, the thermogenic response to single meals A and B containing 38% of weight maintenance energy for each subject (731-994 kcal) was studied by indirect calorimetry under two situations: (1) at rest over a 4 hr period and (2) during graded exercise on a bicycle ergometer at four stepwise workloads (0,80, 200, and 300 kg/min). A postabsorptive control exercise was also performed in order to assess the net effect of the meal during exercise. Eating alone increased the energy expenditure by +0.18 +/- 0.07 kcal/min with meal A and +0.13 +/- 0.06 kcal/min with meal B. There was a positive correlation (r = 0.84, p less than 0.01) between the % energy derived from protein and the thermogenic response expressed as % of the energy content of test meal. Exercise failed to influence the thermogenic response to meals since the overall net increase in energy expenditure induced by the meals while exercising was not different from that obtained at rest: +0.22 +/- 0.17 kcal/min and +0.15 +/- 0.13 kcal/min with meal A and meal B, respectively. This study failed to show any interaction between exercise and postprandial thermogenesis in elderly individuals.

Aged↗
PubMed1987

Benefits associated with WIC supplemental feeding during the interpregnancy interval.

Interpregnancy WIC supplementation was evaluated by comparing maternal nutritional status indicators and subsequent birth outcomes of 703 WIC participants divided into two groups. Study group women received postpartum benefits for 5-7 mo while control group women received postpartum benefits for only 0-2 mo. Both groups received prenatal benefits during each of two study pregnancies. Infants born to study group women had a higher mean birthweight (131 g) and birthlength (0.3 cm) and a lower risk of being less than or equal to 2500 g. Additionally, at the onset of the second pregnancy study group women had higher mean hemoglobin levels and lower risk of maternal obesity. These results suggest that postpartum WIC supplementation has positive benefits for both the mother and her subsequent infants.

Birth Weight↗
PubMed1986

Stable isotope studies of zinc absorption and retention in young and elderly men.

Zinc absorption was determined with 67Zn and 70Zn, stable isotopes of zinc, in six young men and six elderly men who were confined to a metabolic unit for 12 wk. Their purified formula diets, supplemented with select food items, contained 15 mg of zinc per day. Zinc absorption was determined twice for each subject by combining zinc enriched with either 70Zn or 67Zn with the formula diet. Serum, urinary, and fecal zinc and zinc balance were determined by atomic absorption spectrometry. Zinc absorption averaged 17% in elderly men, significantly less than average zinc absorption of 31% in young men. Serum zinc was also lower in elderly men and increased in both groups during the course of the study. Zinc balance did not differ between groups, and endogenous zinc losses were less in the elderly than in the young men. The results suggest that while zinc absorption is less in elderly men than in young men, the lower absorption may reflect a lower requirement for absorbed zinc by the elderly. Alternatively, less efficient zinc absorption could result in decreased endogenous losses.

Absorption↗
PubMed1985

Iron stores in users of oral contraceptive agents.

A comparison of serum ferritin and other parameters of iron status was made between 46 women taking oral contraceptive agents (OCAs) for two or more years continuously and 71 women who never took OCAs. The mean serum ferritin level for the OCA users was 39.5 +/- 21.5 ng/ml and the control group mean level was 25.4 +/- 15.96 ng/ml, which is significantly different at p less than 0.001. Serum transferrin, serum iron, TIBC, MCH and MCHC levels were significantly greater for the OCA users group. Significantly lower RBC and hematocrit levels were found for OCA users while other parameters, hemoglobin, MCV and percent transferrin saturation, were not significantly different. No major differences in subject characteristics and dietary traits were evidenced, except a difference in reported menstrual cycle losses and a higher heme iron content in the diet of the OCA users.

Adolescent↗
PubMed1985

Nitrogen utilization, enzyme activity, glucose intolerance and leukocyte chemotaxis in human experimental zinc depletion.

We previously reported significant decreases in plasma, whole blood, urinary, seminal and fecal zinc in six young men consuming a semipurified formula diet providing 0.28 mg zinc and 0.8/kg protein per day for 4-9 weeks. During a one-week baseline period, 15.7 mg of zinc (as ZnSO4) were fed; three of the men were repleted with 6.0, 23.2 or 46.3 mg zinc for 2-5 weeks. Biochemical and functional measures of zinc status other than tissue zinc levels were also monitored. No one parameter appeared to parallel dietary zinc status in all subjects, although significant mean changes were seen in serum and leukocyte alkaline phosphatases. Inconsistent changes were noted in erythrocyte delta-amino levulinic acid dehydratase, plasma alkaline ribonuclease and the serum alkaline phosphatase isoenzymes. Nitrogen balance was unaffected by zinc nutritional status. However, alterations in hair root growth phase and morphology, decreases in lymphocyte counts and in transferrin levels during depletion suggest impairment in protein synthesis. Impaired leukocyte chemotaxis and clinical signs indicative of decreased resistance to infection were also noted.

Adult↗
PubMed1985

Incidence and duration of breast-feeding in a health maintenance organization population.

A breast-feeding incidence and duration study in a heterogeneous population confirmed the increased incidence of breast-feeding reported among American women. Of 632 women delivering between May and August of 1980, 66% chose to breast-feed, a decision determined to be significantly related to race, age, marital status, and parity. Cesarean deliveries discouraged breast-feeding, whereas nursing immediately after delivery and keeping the infant in the room during the hospital stay encouraged breast-feeding. Of 417 women who were breast-feeding, 58% had stopped by four months postpartum, a decision found to be related significantly to race, age, and receiving formula in the hospital. Formula supplementation in the hospital was associated with a shorter breast-feeding period. The most rapid decline in breast-feeding occurred in the first two weeks postpartum. Because this is the period in which women are most likely to discontinue breast-feeding, it could be a productive target period for support and assistance by health professionals.

Age Factors↗
PubMed1985

Living arrangements and dietary patterns of older adults in the United States.

Living arrangements and dietary patterns were examined for 3,477 adults aged 65 to 74 from the first National Health and Nutrition Examination Survey 1971 to 1974 (NHANES I). Several indicators of dietary variety, diet composition, and energy and nutrient intake from both the 24-hour recall, and the dietary frequency questionnaires were analyzed. Dietary patterns of older men were associated more strongly with type of living arrangement and income compared with older women. Men living with a spouse consistently had more favorable dietary patterns than either those living alone or those living with someone other than a spouse. Low income men who were not living with a spouse were at highest risk of poor dietary intake. Income was associated more consistently with the dietary indicators than type of living arrangement for women. Income, however, was still a less consistent influence on dietary patterns of older women compared to older men.

Aged↗
PubMed1982

Autoregulatory homestatic nature of energy balance.

This paper proposes a new theory regarding energy regulation in man. Current theory states that similar adults have similar energy requirements when engaged in similar activities. As a corollary, if activities remain constant and energy intake is altered, weight will change. This theory has been unable to explain the repeated observations that individuals of the same sex and age and engaged in similar work show a mean weekly coefficient of variation in energy intake of about 16% without significant fluctuations in body weight. Furthermore, repeated studies have failed to show any individual "pattern" relating energy intake to output. This lack of pattern has been attributed either to methodological error or to the fact that human energy requirements cannot be determined by current methods. This paper shows that neither case is correct. The explanation lies in the stochastic stationary nature of energy requirements. Because of the nature of significant intraindividual variations noted in all experiments, "requirement" is a dynamic concept, and energy balance will vary as a matter of course about zero. The implications of this for the individual, society, and policy are enormous and are discussed herein.

Body Weight↗
PubMed1982

Use of enriched stable isotopes to determine zinc and iron absorption in elderly men.

The absorption of zinc and iron was determined in seven elderly men using the enriched stable isotopes 70Zn and 58Fe. Analyses of isotopic ratios were done using thermal ionization magnetic sector mass spectrometry on chloride solutions of zinc and of iron after separation of zinc from fecal samples by ion exchange and of iron by solvent extraction. Mean apparent zinc absorption in the seven subjects was 17.3 +/- 3.1% (mean +/- SEM) and mean iron absorption was 7.9 +/- 2.5% (mean +/- SEM) when fed a semipurified diet containing 15 mg of zinc and 10 mg of iron daily. Quantities absorbed were equivalent to an average of 2.6 mg of zinc and 0.8 mg of iron per day. These average zinc and iron values are close to previous estimates of endogenous losses of zinc and iron.

Absorption↗
PubMed1982

Copper absorption in elderly men determined by using stable 65Cu.

The apparent absorption of copper was determined in seven elderly men using the stable isotope 65Cu. Analysis of isotopic ratios of copper was done using thermal ionization, magnetic sector mass spectrometry after separation of copper from fecal samples by ion exchange chromatography. Mean apparent copper absorption during the first metabolic period in five men was 23.9 +/- 1.4% (mean +/- SEM) when fed a semipurified diet containing 3.3 mg of copper daily and 9 to 19 g nitrogen from egg albumin. Mean apparent copper absorption in five men during the second metabolic period was slightly but significantly higher, 27.7 +/- 0.31% (mean +/- SEM) when their diet contained 3.3 mg of copper per day and 4.0 to 5.7 g of nitrogen from egg albumin. The quantity of copper absorbed was equivalent to 0.8 mg per day in the first metabolic period and 0.9 mg during second metabolic period and was sufficient to maintain copper balance in these elderly men.

Aged↗
PubMed1981

Zinc, copper, and iron balance in elderly men.

Two-3-wk balance studies for zinc, copper, and iron were carried out in six elderly male subjects who were confined to a metabolic unit for a long-term study (12 wk) with constant dietary mineral intake. Average zinc balance was 0.1 +/- 0.05 (mean +/- SEM) and serum zinc increased in all subjects during the course of the study. Average copper balance was 0.06 +/- 0.06 (mean +/- SEM). There was no significant change in serum copper ceruloplasmin, but all were within normal ranges except for elevated serum copper in one subject who appeared to be in negative copper balance. Iron balance appeared to be negative, -0.44 +/- 0.16 (mean +/- SEM), despite improved blood iron parameters in five of six subjects. Results of this long-term balance study suggests that current dietary recommendations of 15 mg of zinc and 2 to 3 mg of copper are adequate for elderly as well as younger adults. However, balance data for individuals must be interpreted with caution, should be used only with other parameters, and should not be relied on exclusively as a basis for dietary recommendations. Additional data are needed to evaluate dietary iron recommendations for elderly men.

Aged↗
PubMed1981

Fluoride balances in pregnant and nonpregnant women.

In planning health protection for pregnant as well as nonpregnant women exposed to fluorides, information about their fluoride metabolism is essential. The authors determined fluoride balances in small groups of young women maintained on two different low-fluoride diets for one or two 21-day periods in a metabolic unit. One diet contained an average of 0.41 mg F/day, and the other contained an average of 0.27 mg F/day. Excretion of fluoride in pooled three-day collections for each subject was about 80% in the urine and 20% in the feces. Pregnant (last half of term) and nonpregnant women demonstrated small negative fluoride balances; the averages were about -0.32 mg F/day and -0.15 mg F/day, respectively. Similar values have been found for young males in other studies. Pregnancy in these subjects did not markedly alter normal fluoride metabolism.

Adult↗
PubMed1980

Behavioral responses to artificial food colors.

Twenty-two young children, maintained on a diet that excluded certain foods, were challenged intermittently with a blend of seven artificial colors in a double-blind trial. Parents' observations provided the criteria of response. One child that responded mildly to the challenge and one that responded dramatically were detected. The latter, a 34-month-old female, showed a significant increase in aversive behaviors. These results further confirm previous controlled studies.

Behavior↗