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Biomedical subjects

D H Calloway

Publications and source records attributed to D H Calloway.

At least 37 records · Page 2Linked to original sources
PubMed1982

Proteins, vitamin A, carotene, folacin, ferritin and zinc in Navajo maternal and cord blood.

Blood samples were obtained from 28 Navajo women at delivery and cord blood samples were collected from their healthy, full-term infants. The concentrations of retinol, folacin, ferritin and zinc in the cord blood fell in the normal range even though some mothers had blood levels suggesting a deficiency. Levels of maternal and cord blood retinol-binding protein were positively correlated. Although marginal and deficient levels of folacin in maternal blood did not result in significantly lower cord blood levels, the strong association indicated a dependence of fetal level upon maternal supply. Birth weight and the developmental indices were not related to any of the maternal or fetal nutrient levels.

Adolescent↗
PubMed1981

Evaluation of lactational performance of Navajo women.

The effect of suboptimal maternal nutrition on lactational performance of 23 Navajo women was studied in terms of milk volume, milk composition, and infant growth. The mean milk volume produced by 10 Navajo women was 634 +/- 113 mg/24 h after approximately 1 month of lactation. The content of protein, lactose, and lipid were within normal limits. Retinol and carotene content were 32.9 +/- 15.7 and 19.7 +/- 6.3 microgram/dl, respectively. Milk folacin averaged 56.4 +/- 23.9 mg/ml. The mean contents of zinc, iron, and copper were 2.8 +/- 1.1, 0.8 +/- 0.6, and 0.3 +/- 0.2 mg/l, respectively. Despite evidence of suboptimal nutriture among these Navajo women, lactational performance was adequate in terms of infant growth, milk volume, and milk composition with the exception of vitamin A which was lower than normal.

Adolescent↗
PubMed1981

Nutritional assessment of pregnant and lactating Navajo women.

Nutritional parameters of 87 Navajo women were assessed at term and in 23 of these women after 1 month of lactation. Serum levels of zinc, retinol-binding protein, folacin, protein, Hb, and ferritin and hair zinc content were determined. Twenty-four-hour dietary recalls were recorded for the subsample of 23 women. Median nutrient intakes were less than 60% of the Recommended Dietary Allowance of calcium, magnesium, zinc, copper, vitamins A (lactation only), D, E, and B6, biotin, and folacin. Serum zinc fell below 50 microgram/dl in 68% of the subsample at term and remained below 65 microgram/dl 43% during lactation. Serum retinol was below normal ( less than 33 microgram/dl) in 24% of these women at term and 23% at 1 month. Low serum folacin (less than 6 ng/ml) was detected in 9% at term and 24% at 1 month. Anemia was present in 15 to 20% of the women. Serum protein, retinol-binding protein, ferritin, and hair zinc were essentially normal. Biochemical findings confirmed dietary inadequacies among Navajo women and indicate needed nutritional improvement.

Adolescent↗
PubMed1981

Nitrate and nitrogen balances in men.

Nitrate is a nitrogen-containing compound that is not detected by the traditional Kjeldahl method of nitrogen analysis. Nitrate balance studies were done in order to determine if nitrate production in the human body contributes to the irrationally positive nitrogen balances that have been reported in healthy adults. Seven healthy young men, confined to a metabolic unit, received five diets for 9 days each: a mixed foods diet, a fiber-free egg formula diet, and egg formula with California small white beans, lima beans, and wheat bran added. Nitrate-nitrogen intake with the mixed foods diet was 75 mg/day and nonnitrate nitrogen intake was 19 g/day; crude Kjeldahl nitrogen balance (intake--(urinary + fecal)) was 0.64 +/- 1.23 g/day. Nitrate-nitrogen excretion exceeded intake by 0.10 +/- 0.05 g/day. With the four other diets, nitrate-nitrogen intake was almost nil (about 2 mg/day) and nonnitrate nitrogen intake was 95 mg/kg body weight; crude Kjeldahl nitrogen balances ranged from -0.63 +/- 0.73 to 0.02 +/- 0.45 g N/day. With these four diets, feces contained about 80 mg nitrate-nitrogen/day and urine contained about 8 mg. Saliva obtained before lunch had about 1 ppm nitrate-nitrogen with the formula diets and 5 ppm with the mixed foods diet. Net synthesis of nitrate is quite variable but appears to be of the order of 100 mg nitrate-nitrogen/day. Although the excess nitrate excretion increased total nitrogen excretion by less than 5%, it could account for as much as 10 to 20% of unexplained positive nitrogen balances previously reported in well-controlled studies.

Adult↗
PubMed1980

Energy requirements and energy expenditure of elderly men.

Basal metabolic rates (BMR) and energy cost of a few activities were measured in healthy men aged 63 to 77 years who were participants in a study of protein requirements (previously reported). The men were confined to a metabolic unit for 47 days and received a defined formula diet. Their body weights were 8 to 19 kg higher than that of younger men of the same heights and their whole body potassium content was 12% less than that of younger men (average 28 years of age) studied in the same unit. BMR of the older men was 1622 +/- 189 kcal/day, a figure 13% below the per diem rate of younger men but the same per unit of body potassium. Energy cost of sedentary activities was related to BMR. Expenditure while lying at rest was 1.22 X BMR and while sitting quietly, 1.30 X BMR; these values are the same as in younger men. Walking level at about 2.5 mph cost 4.51 +/- 0.34 kcal/min (about 4 X BMR) and cycling at a comfortable load (300 to 400 kpm) only slightly more. Energy intake required to maintain body weight of these men, who were sedentary except for 30 min of cycling daily, was 2554 +/- 222 kcal/day, or about 1.6 X BMR. Minimum maintenance energy requirement (i.e., ambulatory but inactive) of healthy older men appears to be 1.5 X BMR, the same as in other age groups.

Aged↗
PubMed1979

Lactation and pregnancy in Iran. III. Hormonal factors.

Lactation failure is common in urban areas of industrially developing countries, but little is known about its epidemiology and causality. The study reported here was undertaken to investigate the serum levels of some hormones other than prolactin that have been shown in animal studies to play a role in lactation, and to examine their relationship to adequacy of lactation and to nutritional and socioeconomic status in urban Iranian women. Serum levels of placental lactogen, growth hormone, cortisol, and thyroid hormones were measured under standard conditions in two groups of pregnant women from low and low middle socioeconomic areas of Teheran, 1 or 2 weeks before parturition and the latter three hormones again in the 3rd month postpartum. Significant differences were found in the biochemical parameters between socioeconomic groups. Hemoglobin and serum albumin values were lower and all the globulin fractions (except alpha 2 globulin during pregnancy), growth hormone and cortisol were higher in the low than the middle socioeconomic subjects, both during pregnancy and postpartum. The discrepancies between the socioeconomic groups were greater postpartum. Growth hormone level was significantly lower in subjects with adequate lactation than inadequate or ceased, and cortisol values show the same trend. No correlations were found between the measured parameters of nutritional status nor free thyroxine values and lactation adequacy. In view of the role of growth hormone and cortisol in stress and malnutrition and some evidence of a reciprocal relationship between growth hormone and prolactin, these hormones may be a link in the chain between the urban environment, malnutrition and lactation failure.

Blood Proteins↗
PubMed1979

Some aspects of bile acid and urobilinogen excretion and fecal elimination in men given a rural Guatemalan diet and egg formulas with and without added oat bran.

Six healthy men were fed a formula diet with and without oat bran and a natural food diet typical of rural Guatemala. No significant difference in dye transit time was found between diets but the Guatemalan diet significantly decreased dye retention time and increased stool frequency. Serum cholesterol and triglyceride levels showed no significant differences among dietary treatments. Excretion of fecal bile acids significantly increased on the Guatemalan and oat bran diets, but fecal bile acid concentration was significantly lower only on the Guatemalan diet. Urinary urobilinogen excretion and fecal urobilinogen concentration were significantly lower with the Guatemalan diet.

Adult↗
PubMed1979

Integumentary loss of calcium.

Integumentary calcium loss was studied in 16 healthy young men. The daily loss by the 16 ambulatory but relatively sedentary young men in 52 determinations of 6-day periods each was 8.7 +/- 1.9 mg/m2 per day (average 15.8 mg/man per day). The amount lost was not influenced by calcium intake (0.1 to 2.3 g/day). In contrast to urinary calcium excretion, which is directly related to protein intake, there was no significant change in integumentary calcium loss with varying protein intakes (1 to 96 g nitrogen per day). No compensatory relationship between urinary and integumentary calcium excretion was noted. During strenuous exercise calcium loss increased to an average of 25 mg in 40 min. There was no compensatory decrease in urinary excretion on the day of strenuous exercise. It was also noted that integumentary calcium loss was not affected by general calcium balance.

Adult↗
PubMed1979

Amino acids in human blood plasma after single meals of meat, oil, sucrose and whiskey.

Six healthy men (21 to 38 years; 58 to 80 kg) consumed an adequate diet in a metabolism unit. At 4-day intervals they ingested test meals and venous blood was drawn before and after ingestion at intervals for 8 hours. Test meals were 100, 200, and 300 g of cooked lean meat and quantities of corn oil, sucrose, and whiskey isoenergetic with 200 g of meat. Plasma was analyzed for 20 amino acids. Mean totals of amino acids (micromoles per liter) were maximally elevated at 1 or 2 hours post cibum for all meals and remained above fasting values at 4 hours, with one exception (glucose meal). At 8 hours they were all below fasting values with one exception (whiskey meal). Individual responses varied so much that mean values are misleading. One subject responded well to ingestion of 100 or 200 g of meat but failed to respond to 300 g of meat, oil, or sucrose. Another subject responded well to oil and sucrose, but failed to respond to 100 or 200 g of meat. Mean total fasting amino acid values for all subjects were relatively constant but values for individual subjects ranged from 16% above to 18% below their own fasting means. Ingestion of whiskey invariably resulted in a significant decline in molar ratios for histidine and a significant increase for threonine.

Adult↗
PubMed1979

Composition of traditional Hopi foods.

Foods produced by the modern Hopi Indians and prepared in traditional ways are generally good sources of essential minerals, especially if plant ash or native crude salt are added in preparation. The predominant whole grain, mature maize-corn products are relatively high in phytate, which may interfere with absorption of some of the minerals present. The use of culinary ash may have played a critical role in maintenance of nutritional health in the presence of interfering substances in the diet, especially if animal foods were in limited supply.

Arizona↗
PubMed1978

Lactation and pregnancy in Iran. I. Social and economic aspects.

Adequacy of lactation was assessed in Teheran women of low (LSE) and lower-middle (MSE) socioeconomic status in the third month postpartum, as part of a study linking nutrition, hormonal status, and lactation. Methods of assessment of nutritional adequacy are discussed. Characteristics of the socioeconomic groups, infant mortality, food beliefs related to lactation, and supplemental feeding practices are described. Of the LSE mothers 15 to 30% and of the MSE mothers 40 to 55% had a fully adequate milk supply in the third month. Substitutes used and affordable by the LSE were nutritionally inadequate. LSE mothers were traditional in their food beliefs. MSE mothers demonstrate the influence of scientific nutrition knowledge. The low percentage of lactation adequacy even in the MSE indicates that other social or health factors associated with urban living conditions may be just as important as economic and nutritional factors in lactation failure.

Energy Intake↗
PubMed1978

Lactation and pregnancy in Iran. II. Diet and nutritional status.

Dietary intake in the third month postpartum and nutritional status during pregnancy close to term were assessed in Iranian urban uomen of low and middle socioeconomic status as part of a study investigating nutrition, hormonal status, and lactation in a population where lactation failure is a serious problem. Dietary intake was assessed by the 24-hr-recall method. The greatest differential in food groups consumed was in animal products, fruit, and vegetables. Intake of nutrients equal to or less than 80% of recommendations in both socioeconomic groups were energy, vitamin B6, folacin, calcium, iron, and zinc. In the low socio-economic group, only average intakes of vitamin C, thiamin and protein met the standards. Significant differences were found between the socioeconomic groups in hemoglobin, hematocrit, serum total protein, and protein fractions, but not in weight and height. The only parameters of nutritional status significantly correlated with adequacy of lactation were postpartum weight and percent of standard weight for height in the low socioeconomic group, and hematocrit values in the middle socioeconomic group. Differences between pregnant and postpartum individual values of the blood parameters were in general greater in the middle socioeconomic group than the low socioeconomic group.

Blood Cells↗
PubMed1978

Protein and energy utilization in men given a rural Guatemalan diet and egg formulas with and without added oat bran.

Healthy men were fed a fiber-free formula diet providing the FAO/WHO Safe Level of egg protein (0.57 g/kg) and a rural Guatemalan diet giving 0.0875 g of protein per kilogram, the recommended dietary allowance for Central America and Panama. For comparison an egg formula diet was fed at the higher protein level, with and without oat bran (0.6 g/kg). All diets maintained nitrogen balance over the 15-day test periods, and balance was distinctly positive at the higher intake of egg protein. Addition of bran doubled the fecal excretion of dry matter and energy; digestibility of energy and protein was reduced 3 to 4%. With the Guatemalan diet, fecal dry matter, nitrogen and energy excretions were nearly four times as high as with egg formula. Relative to egg ( = 100%), protein digestibility of the Guatemalan diet was 78% and total digestible energy was 92%. Present recommended dietary allowances of protein maintain nitrogen equilibrium at an energy intake of 40 kcal/kg in spite of the large fecal losses.

Adult↗
PubMed1976

Nitrogen retention in men fed varying levels of amino acids from soy protein with or without added L-methionine.

A metabolic study was undertaken to determine methionine requirements of six young men fed soy protein isolate (SB) for 9-day periods. Formula diets contained 9 g of nitrogen from intact proteins with glycine and alanine added. Nitrogen derived from intact protein was g per day: reference eggwhite (EW), 3.0, 4.5, and 6.0; and SB, 3.0, 4.5, 6.0, and 7.5. SB diets were fed with and without addition of L-methionine to raise the total amount of sulfur amino acids (SAA) to 900 mg. Mean nitrogen balance was positive with diets containing at least 4.5 g EW, 6.0 g SB, and 4.5 gSB with methionine added. Individual requirements for SAA were: for one man between 320 and 480 mg; for three, between 480 and 640 mg; for one man, between 640 and 800 mg; and for the sixth man, between 640 and 900 mg. Thus 900 mg, stipulated by the 1973 FAO/WHO Committee as being necessary for the 70 kg reference man, was sufficient for all participants. Nitrogen balance was equally improved by increasing the SB nitrogen level by 1.5 g or adding methionine at each level of SB fed.

Adult↗