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Biomedical subjects

D H Calloway

Publications and source records attributed to D H Calloway.

At least 19 recordsLinked to original sources
PubMed1992

Estimated protein intakes of toddlers: predicted prevalence of inadequate intakes in village populations in Egypt, Kenya, and Mexico.

This paper presents a probability assessment of the adequacy of protein intakes of toddlers (aged 18-30 mo) in study communities in Egypt, Kenya, and Mexico judged in relation to FAO/WHO/UNU estimates of requirements. Effects of supplementing amino acid intakes, or of assuming lower bioavailability for lysine are also considered. In Egypt and Mexico existing protein intakes of toddlers were adequate. In Kenya existing intakes were marginal. Total protein intake was low and often lysine or tryptophan concentration was low. If Kenyan intakes met estimated energy requirements, protein intakes would be adequate. We conclude that protein intake is unlikely to be a primary limiting factor for toddler growth and development, and the benefit to be expected from increasing the intake of limiting amino acids is marginal. Reported associations of animal-source protein and energy with growth, size, and psychologic function of these toddlers are unlikely to be causally attributable to inadequacy of protein intakes.

Amino Acids↗
PubMed1992

Estimated mineral intakes of toddlers: predicted prevalence of inadequacy in village populations in Egypt, Kenya, and Mexico.

Intakes of minerals and factors that might affect their bioavailability were estimated for 255 toddlers aged 18-30 mo living in villages in Egypt, Kenya, and Mexico. Mean intakes over 1 y were compared with international-requirement estimates by using a probability approach. The prevalence of iron intakes likely to be inadequate to prevent anemia was estimated as 35% in Egypt, 13% in Kenya, and 43% in Mexico. The prevalence of zinc intakes likely to be inadequate to meet basal requirements was estimated as 57% and 25% in Kenya and Mexico, respectively, but only 10% in Egypt, where the use of yeast-leavened breads was judged to have improved zinc availability. There was no suggestion that estimated copper or magnesium intakes were inadequate, but calcium intakes in Kenya and Egypt were well below recommended amounts. Studies of factors affecting mineral bioavailability in the diets of these countries' populations could suggest dietary changes that might improve effective mineral intake with minimal cost.

Calcium, Dietary↗
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↗
PubMed1976

Nitrogen retention in men fed isolated soybean protein supplemented with L-methionine, D-methionine, N-acetyl-L-methionine, or inorganic sulfate.

The ability of various sulfur-containing compounds to replace L-methionine (L-Met) was investigated by metabolic balance studies in man. N-acetyl-L-Methionine (AcMet), D-methionine (D-Met), and sodium sulfate (Na2SO4) were used to supplement a diet deficient in sulfur amino acids. The daily diet contained 4.5 g nitrogen (N) from isolated soybean protein (SB) and 4.5 g from glycine and alanine (9 g total N). SB diet was given alone or supplemented to six adult men for periods of 9 days after a standardization period with an equal N eggwhite diet, preceded by a 2-day zero N adaptation period. Supplements provided equivalent amounts of sulfur to that present in 420 ml L-Met, the amount added to SB to bring the total sulfur amino acid content to 900 mg/day. AcMet was as benfeficial as L-Met in improving N balance but D-Met was not as effective as L-Met. Difference between balances obtained with L-Met and Na2SO4 was not significant due to large variation in response to Na2SO4. While addition of D-Met to SB did not result in significantly greater N retention than unsupplemented SB, NA2SO4 addition did cause increased N retention.

Adult↗
PubMed1976

Basal metabolic rate and work energy expenditure of mature, pregnant women.

Resting and working metabolic rates and physical fitness of twenty-one mature women were studied at various intervals during the last half of pregnance and in sixteen of them again eight to twelve weeks postpartum. Basal rate (BMR) was increased more than body weight during pregnancy, and there was a small drop in BMR per unit body mass near term. Data on lean body mass (40K) suggest that the small terminal fall in BMR is not explained by a shift in body composition toward increased fat or water. The increase in energy cost of work paralleled the gain in body weight during preganacy. Net energetic efficiency thus appeared to be higher for work performed during pregnancy, if recovery rates are assumed to be uniform. However, according to their heart rate reponses to fixed hard work, the women were less fit during pregnancy than they were postpartum, with the level of fitness decreasing as pregnancy advanced. The prolonged rate of recovery suggests that oxygen uptake may be increased for a longer period after work in the pregnant woman. If this is true, energy expenditure will be seriously underestimated by the application of energy cost figures obtained in the conventional manner.

Adult↗
PubMed1976

Energy expenditure and consumption of mature, pregnant and lactating women.

Activity patterns, energy expenditure, and energy and protein consumption of mature women were determined during preganncy and lactation. Homemakers of average economic status from a mixed population were not significantly more active than teenage women, but the range of activities was greater. Average energy output for the latter half of gestation was 2,200 to 2,300 kcal per day; per unit of body weight, the mean was 32.5 +/- 4 kcal per kilogram for the twenty-week period. A small decline of 6 per cent in energy expenditure was noted near term. Allowing for deposition of fetal and material tissue, the average metabolizable energy need for this group was about 35 to 36 kcal per kilogram for the latter half of pregnancy. These data show that a pregnant woman of reference body weight (68 kg.) may vary in energy output by 800 to 900 kcal per day, depending on occupation. Homemakers with small children and especially those who work outside the home constitute a high energy work category. Thus, the need for considering work pace and work load, as well as body mass, in estimating the energy requirement during pregnancy was confirmed. Average daily energy intake reported was 1,955 kcal or 28.5 kcal per kilogram for the latter half of gestation. A mean protein intake of 1.17 gm. per kilogram per day represented 17 per cent of gross energy consumed. It is questionable whether the energy level consumed by these women was sufficient to maintain positive nitrogen balance on the days recorded. Lactating homemakers expended an average of 30 kcal per kilogram per day, exclusive of milk production. Energy intake was 30 kcal per kilogram, and was equal to 74 per cent of need when adjusted for milk production. Non-lactating women expended 34 kcal per kilogram per day, 13 per cent above the values for lactating women. Average energy intake of non-lactating women was 19 kcal per kilogram, with protein intake representing 19 per cent of energy consumed for both groups.

Adult↗