Some vitamin sources relating to plasma homocysteine provide not only folate but also vitamins B-12 and B-6.
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Aged↗
Biomedical subjects
K M Koehler
Publications and source records attributed to K M Koehler.
Structure and function of the zeta-globin upstream regulatory element.
The human zeta-globin promoter contains a strong positive regulatory element in the 5' flanking region, designated the zeta-globin upstream regulatory element (URE). In this study, we define the minimal sequences required for URE function and characterize the associated protein-DNA interactions. Deletion experiments show that the URE spans a 60 bp region located between 220 and 279 bp 5' to the transcription start site. Further subdivision of this region shows that multiple cis acting sequences are present. Electrophoretic mobility shift assays demonstrate that the erythroid transcription factor GATA-1 binds a site at -230, and Sp1 and an unidentified factor bind a CCACC site at -240. The unidentified CCACC factor is distinct from two other CCACC factors, EKLF and BKLF/TEF-2. A third complex contains a novel DNA-binding activity that interacts with a site in the -269 to -255 region, designated URE binding factor (URE-BF). This factor is present in K562 cells that express zeta-globin, but is absent in the OCIM1 cell line, a human erythroid cell line that does not express zeta-globin. URE-BF appears to interact with a GATA factor, since formation of the URE-BF complex can be prevented by the presence of unlabeled oligonucleotides containing GATA sites. Finally, increasing the distance from the -230 GATA site to the two upstream sites causes a progressive decrease in zeta-globin promoter activity. There is no indication of a requirement for GATA-1 to be on the same side of the DNA helix as the other upstream factors. These results show that zeta-globin promoter function is highly dependent on a 60 bp region to which at least three different factors bind. Two of these factors may represent DNA-binding proteins not previously identified as important for regulation of globin gene expression. It is likely that these factors interact physically to create a functional regulatory unit.
Cell Line↗
Food preferences, practices, and cancer-related food and nutrition knowledge of southwestern American Indian youth.
BACKGROUND: Pathways to Health is a cancer prevention and health promotion curriculum for fifth- and seventh-grade Navajo and Pueblo students living in New Mexico. METHODS: A diet and nutrition questionnaire was administered to 1007 fifth- and seventh-grade students before beginning the Pathways to Health intervention. Sections of the questionnaire included listing favorite foods, frequency of intake of selected foods (e.g., "How often do you eat vegetables?"), targeted food practices (e.g., "When you eat chicken, do you eat the skin?"), and applied dietary fat and fiber knowledge questions. Descriptive analyses were generated by grade, gender, and tribe. RESULTS: Students' favorite foods were pizza, hamburgers, and tacos. Only 35.7% of students reported consuming the U.S. Dietary Guidelines recommendation of two or more daily servings of fruit, with only 19.3% reporting more than once-a-day intake of vegetables. The mean score (percent correct responses) to questions identifying common food sources of dietary fat and fiber, and other cancer-related nutrition knowledge questions, was 45.2% and 57.9% for fifth- and seventh-grade students, respectively. CONCLUSIONS: These and related data support the need for nutrition education interventions in this population that target essential cancer prevention skills and motivational information required to make positive dietary choices.
Adolescent↗
Vitamin supplementation and other variables affecting serum homocysteine and methylmalonic acid concentrations in elderly men and women.
OBJECTIVE: An elevated serum concentration of the metabolite, homocysteine (Hcys): 1) can indicate folate or vitamin B12 deficiency, 2) is an independent risk factor for vascular disease. The metabolite, methylmalonic acid (MMA), is elevated in deficiency of vitamin B12, but not folate. The purpose of this study was to determine the effect of self-selected vitamin supplementation and other variables on serum Hcys and MMA concentrations in elderly men and women. METHODS: Serum concentrations of Hcys, MMA, folate and vitamin B12 were measured for elderly volunteers, age 68-96 years, and compared for those consuming (26 men, 25 women) and not consuming (24 men, 25 women) self-selected vitamin supplements. RESULTS: Compared with the nonsupplemented group, the supplemented group had lower mean serum MMA (208 +/- 162 vs. 241 +/- 98 nmol/L [+/- SD]) and Hcys (9.5 +/- 2.6 vs. 11.2 +/- 2.7 mumol/L); and higher serum vitamin B12 (391 +/- 174 vs 292 +/- 107 pmol/L), and serum folate (46 +/- 15 vs. 24 +/- 10 nmol/L) p < 0.05. Among all 100 subjects, the prevalence of serum vitamin B12 < 221 pmol/L (300 pg/mL) was 18; MMA > 271 nmol/L, 16; Hcys > 16.2 mumol/L, 3; folate < 5.0 nmol/L, none. Based on serum vitamin B12 < 221 nmol/L with elevated serum MMA, vitamin B12 deficiency was probable in seven subjects, of whom two were supplemented. All three subjects with elevated serum Hcys had elevated serum MMA as well, suggesting vitamin B12 deficiency or renal insufficiency. A stepwise linear regression model for serum Hcys explained 61.7% of the variance, and included (in order) serum creatinine, folate, vitamin B12, albumin, age and body mass index (BMI). A model with serum MMA replacing serum vitamin B12 explained 64.1% of the variance in serum Hcys. Folate did not enter the model for supplemented subjects, supporting a "threshold effect": serum Hcys was inversely related to serum folate at lower serum folate (nonsupplemented subjects), but at higher serum folate (supplemented subjects), the relationship was flat. In supplemented subjects, serum Hcys was still related to vitamin B12 status, confirming that tissue deficiency of the vitamin was present. CONCLUSIONS: Results showed potential usefulness of serum MMA and Hcys in identifying subclinical or tissue deficiency of vitamin B12. Clinicians should be aware of the risk of vitamin B12 deficiency in older people and of current screening algorithms using serum metabolites. These elderly volunteers had generally good folate status; nevertheless, some subjects seemed likely to benefit from an improvement in folate status that would reduce their serum Hcys within the normal range. The role of serum creatinine in the normal range in predicting serum Hcys, a vascular disease risk factor, remains unexplained.
Aged↗
Associations of fat and muscle masses with bone mineral in elderly men and women.
Associations of fat and muscle masses with bone mineral status were studied in 301 men and women aged > or = 65 y. Bone mineral and soft tissue composition were estimated by using dual-energy X-ray absorptiometry. Univariate correlations suggested that muscle is associated more closely than fat with bone mineral content (BMC) as well as with bone mineral density (BMD) in men. In women, however, correlations of BMC with muscle were only slightly greater than those with fat and correlations with BMD were consistently greater with fat than with muscle. This suggests that correlations of BMC with muscle are influenced by bone and body size, especially in women. A multiple-regression model was developed that adjusts BMC for bone area, knee height, age, and the independent effects of fat and muscle. In men, muscle remained more closely associated with adjusted BMC than with fat. In women, fat mass was associated significantly with BMC but muscle mass was not. The exception was for women taking estrogen, in whom neither fat nor muscle was associated significantly with adjusted BMC. This study suggests that body fatness may be more important than muscle in maintaining bone mineral in elderly women not taking estrogen.
Absorptiometry, Photon↗
Serum albumin is associated with skeletal muscle in elderly men and women.
Serum albumin concentrations decrease with age and values < 38 g/L are associated with increased morbidity, mortality, and disability in the elderly. It is not clear to what extent the decreases are associated independently with changes in metabolism, dietary intake, physical activity, morbidity, or body composition. We examined associations of serum albumin with age, protein and energy intakes, physical activity, morbidity, and muscle mass in 275 men and women aged 60-95 y. Serum albumin was measured with the bromcresol green procedure. Usual dietary intake and physical activity were quantified through questionnaires. Morbidity was ascertained from medical history, questionnaire, and examination. Muscle mass was estimated from dual-energy X-ray absorptiometry. In multivariate analyses, serum albumin was associated significantly with muscle mass after age, protein intake, physical activity, and comorbidity were controlled for in men and women. This study suggests that decreases with age in serum albumin concentrations are associated with muscle loss (sarcopenia) in the elderly. This association is independent of other factors that may affect muscle mass and albumin concentration. We suggest that the increased risk of disability with low serum albumin concentrations observed in the elderly may actually reflect an association with sarcopenia.
Aged↗
Evaluating population folate exposure through a complete frequency distribution.
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Aged↗
Identification of a major positive regulatory element located 5' to the human zeta-globin gene.
The function of the zeta-globin promoter was studied using a series of zeta-globin promoter deletion constructs to drive luciferase expression in transiently transfected human erythroleukemia cells. The promoters were used without enhancers, or with enhancers derived from the beta-globin locus control region and the alpha-globin HS-40 enhancer. When transfected into K562 cells, which express zeta-globin, comparable amounts of activity were obtained from the -557 and -417 zeta-luciferase constructs and the alpha-luciferase constructs when no enhancers or the alpha-globin locus enhancers were used. When the constructs were transfected into OCIM1 cells, which do not express zeta-globin, the zeta-globin promoters were at best 20% as active as the alpha-globin promoters. When sequences from -417 to -207 5' to the zeta-globin mRNA cap site were deleted, up to 95% of the zeta-globin promoter activity was lost in K562 cells. Reinsertion of these sequences into zeta-luciferase constructs missing the -417 to -207 region showed that the sequences lack classical enhancer activity. Point mutation of a GATA-1 site at -230 reduced promoter activity by 37%. Point mutation of a CCACC site at -240 had no effect. Electrophoretic mobility shift assays indicated that the -230 GATA-1 site has a relatively low affinity for GATA-1. These experiments show the presence of a strong positive-acting element, located between -417 and -207 bp 5' to the zeta-globin mRNA cap site, is necessary for high-level promoter activity in K562 cells. This element requires GATA-1 and additional unknown factors for maximal activity.
Base Sequence↗
Iron stores and iron absorption: effects of repeated blood donations.
We assessed changes in iron stores and iron absorption after repeat blood donations using a combination of biochemical measures of iron status: ferritin, hemoglobin, and transferrin saturation. Thirty-six volunteers with a mean (+/- SD) age of 67.7 +/- 3.7 y donated an average of 15 units of blood over 3.5 y. Initial iron stores were 12.45 +/- 3.09 mg/kg for men and 12.53 +/- 3.24 mg/kg for women. Of the 20 men and 16 women who completed the study, 6 men and 10 women were taking a self-selected supplement providing approximately 20 mg Fe/d. Dietary iron intake was determined to be approximately 20 mg/d for men and approximately 18 mg/d for women. Decreases in iron stores in supplemented men were not significantly different from those in nonsupplemented men: 9.52 +/- 2.57 and 11.31 +/- 2.74 mg/kg, respectively. Nonsupplemented women showed a significantly (P < 0.05) greater decline in iron stores than did supplemented women: 13.09 +/- 2.46 and 10.60 +/- 4.15 mg/kg, respectively. Mean maximal iron absorption was approximately 4.10 mg/d for men and approximately 3.55 mg/d for women regardless of iron intake.
Absorption↗
Cross-sectional age differences in body composition in persons 60+ years of age.
BACKGROUND: There is little information for age differences in body composition in elderly people > 65 years of age, especially for those > 80 years. As the proportion of people older than 65 years is expected to nearly double during the next few decades, this information is needed. METHODS: Age differences in body composition and anthropometry were examined in 316 men and women aged 60 to 95 years. Multiple components of body composition were quantified using dual energy X-ray absorptiometry and isotope dilution methods, and expressed in molecular and cellular models. Analysis of variance was used to test for differences between age groups 60 to 70, 71 to 80, and > 80 years in each sex. Body composition components were regressed on age, controlling for knee height, fat-free mass, or total body fat. Age-adjusted correlations were calculated with anthropometric variables. RESULTS: Fat-free mass (FFM), body cell mass (BCM), and appendicular skeletal muscle (ASM) decreased with age in both sexes. ASM decreased relative to FFM in both the men and the women, while BCM decreased relative to FFM in the women only. Total fat mass and percent body fat decreased with age in the women, but not in the men. Body fat distribution did not appear to change with age. Anthropometric indices, muscle area and waist/hip ratio, had low correlations with muscle mass and fat distribution. CONCLUSIONS: "Sarcopenia," or muscle loss, continues to occur into old age, and may have significant impacts on physical function and health status. New anthropometric techniques are needed for assessing muscle loss with age.
Adipose Tissue↗
The New Mexico Aging Process Study.
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Aged↗
Energy restriction reduces metabolic rate in adult male Fisher-344 rats.
Energy restriction, without malnutrition, prolongs the maximum life span of laboratory rodents. A reduction in metabolic rate has been proposed as a potential mechanism for increased longevity. The present study examines changes in metabolic rate of adult rats after a 6-wk period of energy restriction. Two groups (n = 6) of 6-mo-old male Fisher-344 rats were studied. Restricted rats were pair-fed a diet equivalent in vitamins and minerals but restricted to 60% of energy consumed by rats eating ad libitum. Average and basal metabolic rates were measured by direct calorimetry over a 24-h period without food. Fat mass and lean body mass were determined by NMR spectroscopy. After 6 wk of restriction, when expressed per kilogram of lean body mass the average metabolic rate was reduced by 14% and basal metabolic rate by 12% compared with the ad libitum diet rats (P < or = 0.01). Reduction of metabolic rate did not seem to be a transient effect of chronic energy restriction in mature rats.
Animals↗
Nutrition and aging.
This article has discussed current knowledge of the nutritional status of the healthy elderly population, possible nutritional risk with respect to individual nutrients, and how nutritional needs of the elderly compare with those of younger adults. Application of these findings to the total elderly population will involve the disciplines of gerontology and medicine with respect to the psychological, social, and economic aspects of aging and to the special needs of the ill and frail elderly segment of this population.
Adult↗
Longitudinal study of dietary intakes and plasma lipids in healthy elderly men and women.
Dietary intakes and blood lipid concentrations were assessed in elderly men (n = 65) and women (n = 92) from 1980 through 1989. Mean age in 1980 was 70 y (range 60-84 y). Health and socioeconomic status was above that found in the general US elderly population. Cross-sectional and longitudinal changes in variables were determined by using least-squares linear regression. No significant cross-sectional differences in energy (kJ/kg), protein (g/kg), total fat, and carbohydrate intake with age was noted. Significant longitudinal decreases in total fat, saturated and polyunsaturated fatty acids, and cholesterol intakes were noted in both men and women. Significant decreases in total, HDL, and LDL plasma cholesterol concentrations were noted over time in both men and women. Ratios of both total and LDL cholesterol to HDL cholesterol increased over time. The decrease in total fat and cholesterol intakes were significantly correlated with the decrease in total plasma cholesterol.
Aged↗
Prediction of iron absorption based on iron status of female blood donors.
Iron stores were assessed in 27 postmenopausal healthy women who donated five units of blood (approximately 485 mL/unit) over approximately 1 y. The mean (+/- SD) age was 67.7 +/- 4.0 y and the average time between successive blood donations was approximately 10 wk (range 8-30 wk). Steady-state iron stores at entrance were 10.59 +/- 3.88 mg/kg body wt (mean +/- SD) and declined to 1.03 +/- 3.20 mg/kg by the fifth donation. Determination of iron stores was based on biochemical measures of iron status at each donation. Iron intakes were 23.3 +/- 10.1 mg/d. From these data we developed equations that can be used to predict the frequency at which healthy postmenopausal women can donate blood without becoming iron deficient. The ability of elderly women to become successful blood donors depends primarily on initial iron stores, iron intake, and frequency of donation. Women with low steady-state iron stores may be able to donate only two times per year without becoming iron deficient.
Absorption↗
The critical path: an evaluation of the applicability of nursing case management in the NICU.
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Humans↗
Meat, poultry, and fish consumption and nutrient intake in the healthy elderly.
Food selection of the healthy elderly may be influenced by life-styles, the food supply, and recommendations related to diet and disease. This study used food group analysis of 3-day diet records to examine red meat, poultry, and fish consumption by free-living, healthy elderly individuals. Dietary data were from 122 women and 97 men (median age = 75 years) who were participants in the New Mexico Aging Process Study in 1984. Mean dietary intake was 1,494 kcal/day for women and 2,079 kcal/day for men--82% and 94% of the Recommended Dietary Allowance (RDA), respectively. Protein, iron, and selected B vitamins were above 100% of the RDA. Women's mean daily intake of meat/poultry/fish was 87.7 g (52.1 g meat, 23.6 g poultry, 12.0 g fish); men's intake of meat/poultry/fish was 121.2 g (78.4 g meat, 21.2 g poultry, 21.6 g fish). Of the total red meat, more than 50% was beef, 20% was pork/ham, and more than 10% was processed meat. For women, meat/poultry/fish provided 14% of total dietary energy, 37% of protein, 13% to 32% of selected B vitamins and iron, 20% of fat, and 34% of cholesterol. Percentages were similar for men. There was no significant association between age and total dietary intake, but food group consumption had distinct associations with age for women and men. Our findings indicate that a moderate but not excessive intake of meat/poultry/fish made a substantial contribution to nutrient intake. The fat contribution of these food groups could be decreased by emphasizing lower-fat selections of meat, poultry, and fish.
Age Factors↗
Efficacy of a nonrestricted fat diet in patients with cystic fibrosis.
We sought to determine if an increased oral intake with a noninvasive nutrition program in patients with cystic fibrosis could influence growth, weight gain, and pulmonary function. Thirty-seven patients, aged 2 to 27 years, were instructed to consume a nonrestricted fat diet during an intervention period of 4 years. The results showed that patients increased the mean energy intake significantly to a level of more than 120% of the recommended daily allowance. The enhanced intake resulted in significant weight gain. Pulmonary function (forced expiratory flow 25%-75%) deteriorated during the 2-year preintervention period but stabilized during the 4-year intervention period. Both male and female patients were able to maintain their established height and weight scores during adolescence. The recommendation for a high-energy diet with no restrictions placed on the fat intake and the control of the steatorrhea by administration of an optimal enzyme dosage is supported by our data. Individualized nutritional counseling should be attempted before implementing invasive nutritional intervention programs.
Adolescent↗