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Biomedical subjects

W C MacLean

Publications and source records attributed to W C MacLean.

At least 37 records · Page 2Linked to original sources
PubMed1983

The effect of decortication and extrusion on the digestibility of sorghum by preschool children.

The effect of decortication and extrusion on the apparent protein quality and digestibility of sorghum (S. vulgare) was evaluated in comparative balance studies in nine children 7-24 months of age. Sorghum provided (as kilocalories) 8% protein and 62% carbohydrate in the study diet. Lysine was supplemented to 3% of protein. Casein provided 6.4% protein kilocalories in the control diet. A mixture of sucrose, dextrimaltose and cornstarch provided carbohydrate. Both diets contained 30% fat kilocalories as soybean-cottonseed oil blend. Balance studies were carried out during the last 6 days of three 9-day dietary periods: control-sorghum-control. Apparent N absorption from sorghum was 81 +/- 4% and did not differ from control. Apparent N retention, 21 +/- 6%, was expectedly lower than the preceeding control (27 +/- 8%, P less than 0.05) and following control (33 +/- 7%, P less than 0.01) values. The control values differed significantly from each other (P less than 0.05). Fecal weights and energy losses showed only minor differences between the two diets. These data contrast sharply with previous results obtained with whole-grain sorghum and suggest that the use of decortication and low cost extrusion processing can markedly improve the apparent protein quality and digestibility of sorghum.

Caseins↗
PubMed1983

Protein quality and oil digestibility of Lupinus mutabilis: metabolic studies in children.

The nutritional quality of lupins (Lupinus mutabilis) for infants and children was evaluated in two sets of balance studies. In the first the digestibility and protein quality of diets based on lupin flour, with and without methionine supplementation, were compared with those of a control diet consisting of casein, sucrose and vegetable oil. Apparent nitrogen absorption from lupin flour (81.8 and 84.3% of intake) was slightly but significantly less than that during casein control periods (87.2 and 86.8% of intake, P less than 0.05 and less than 0.001). Apparent nitrogen retention from unsupplemented lupin (15.6 +/- 5.8% of intake) was significantly less than that from casein in the corresponding control periods (29.8 +/- 4.9%, P less than 0.001); a small but significant (P less than 0.05) increase in nitrogen retention was observed during the control period following the lupin diet when compared with that preceding it. Methionine supplementation of lupin produced a marked improvement in apparent nitrogen retention (to 22.2 +/- 6.9%, P less than 0.05). In the second set of studies the digestibility of lupin oil was compared with that of a blend of soybean and cottonseed oils (50:50). Excretion of fecal fat (9.8 +/- 3.0% of intake) and fecal energy (6.7 +/- 1.2% of intake) with the diet containing lupin oil were similar to those observed with the control diet. Both the protein quality and oil digestibility of Lupinus mutabilis are very similar to those from soybeans processed in a similar manner. For certain countries the lupin could be a valuable source of protein and edible oil for human consumption.

Body Weight↗
PubMed1983

Plasma free amino acids in children consuming lupin protein with and without methionine supplementation.

Plasma free amino acids were measured in the fasting state and 3 and 4 hours postprandially in children after 9 days consumption of diets in which lupin provided all of 6.4-6.7% protein kcal, either with supplementation of 2% (grams/gram protein) DL-methionine (L & Met, n = 9) or with an isonitrogenous amount of urea (L & U, n = 10). Fasting concentration of total amino acids (TAA) and of essential amino acids (TEAA) and the TEAA:TAA molar ratio did not differ between diets. Fasting Met concentration (15 +/- 4 mumol/liter) and the Met:TEAA ratio (0.021 +/- 0.005) were markedly depressed after 9 days of L & U. Supplementation with Met caused an expected increase of Met concentration (25 +/- 6 mumol/liter) and the Met:TEAA molar ratio (0.039 +/- 0.007) and a profound decrease of Thr concentration (119 +/- 28 to 77 +/- 22 mumol/liter) and Thr:TEAA (0.165 +/- 0.027 to 0.124 +/- 0.028). Postprandially after L ", Met and Met: TEAA did not change from their low fast ing values. After L rMet, Met and Met:TEAA increased significantly relative to fasting values. Threonine concentration increased but the Thr:TEAA ratio decreased significantly (0.124 +/- 0.028 to 0.111 +/- 0.027). These studies confirm Met as the first-limiting amino acid in lupin protein and suggest that Thr becomes limiting when Met is provided in adequate amounts.

Amino Acids↗
PubMed1982

Experience with a mixture of wheat-noodles and casein in the initial dietary therapy of infants and young children with protein-energy malnutrition or acute diarrhea.

The usefulness of a mixture of wheat noodles and a casein-based formula in the early management of 11 children with second or third degree malnutrition and of ten better nourished children with acute diarrhea was studied. Response of the malnourished children, gauged by clinical course and balance studies, paralleled that previously documented using only casein-based formula diets. Children with acute diarrhea recovered well but had expectedly higher fecal energy losses than previously seen in healthy children consuming the same diet. Diets containing substantial amounts of wheat noodles, a low cost widely available staple, can be appropriately used in the refeeding of chronic malnutrition and acute infectious enteritis.

Acute Disease↗
PubMed1981

Respiratory hydrogen secretion: a simple test of bowel adaptation in infants with short gut syndrome.

The prime goal in the management of infants with short gut syndrome is the smooth transition from total parenteral alimentation to total gastrointestinal alimentation. Such transition is dependent upon early feeding to actively promote the intestinal mucosal hyperplasia that is the key to eventual oral alimentation. A modular hyposmolar formula was previously reported to be successful in promoting the intestinal adaptation in several infants with short gut syndrome. Progression of the daily diet was dependent upon the day's clinical response, i.e., whether a change in volume or substrate composition resulted in increased stooling or diarrhea. Diarrhea occurs when the substrate load exceeds the absorptive capacity of the intestine and may be severe enough to require a return to parenteral alimentation until intestinal recovery is complete. Monitoring of daily breath H2 has provided an early warning mechanism to indicate carbohydrate overload in the adapting bowel before clinical signs of malabsorption occur. It provides an accurate daily measure of the bowel's ability to utilize the specific volume and caloric density it is being presented, thereby allowing diet advancement in a controlled fashion. The use of the breath H2 test in three infants with short gut syndrome has assisted in the transition to oral alimentation in 3 to 20 wk without the complications of severe diarrhea.

Adaptation, Physiological↗
PubMed1981

Preterm milk.

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Female↗
PubMed1981

Determinants of growth among poor children: nutrient intake-achieved growth relationships.

Seven-day individual weighed dietary intakes and anthropometric measurements were determined in 123 children, 2 to 19 yr of age, from 26 poor families in Lima: each included one child who had been malnourished, six were adopting families. Heights and weights were converted to "ages" based on Boston reference data and local data, then to "quotients" as percentages of actual ages. Mineral and vitamin intakes were expressed as amounts per day and per 1000 kcal, calories and protein as percentages of FAO/WHO recommendations for age and height age and of modified recommendations based on size of Peruvian children. Regression analyses identified common sources of nutrients and greater dependence of intakes on body size than on age. Analysis of covariance for sex identified different nutrient-growth correlations. Polynomial regression analysis identified percentage protein from animal sources and percentage fat calories as having significant quadratic as well as linear correlations with achieved growth. In males, multiple regression analysis identified percentage protein from animal sources and beta-carotene intakes as strongly associated with achieved height and weight, and percentage fat calories as strongly associated with weight quotient/height quotient ratios. In females the correlations were not as strong, possibly because a significant percentage had reached the menarche some time before the survey and were probably no longer growing. Nevertheless, calorie intake, as a percentage of the recommendation for height age, was prominent in the regressions for height quotient and percentage fat calories in that for weight quotient. The very strong association of animal protein intake with male height, despite seemingly generous total protein intakes, is difficult to reconcile with current recommendations. The possible role of vitamin A (as beta-carotene) has potentially important implications for food policies.

Adolescent↗
PubMed1981

Determinants of growth among poor children: relation of nutrient intakes to expenditure for food.

The growth status and the nutrient intakes of 123 children from 26 urban poor families in Peru were related to per capita expenditure for food. Children from six better off families were taller and heavier (p less than 0.001), with no difference in weight for height. They had significantly higher calorie and total protein intakes (as percentage of recommended) and higher intakes of animal protein, fat, calcium, carotene, riboflavin, and vitamin C. When macronutrient intakes were expressed as percentages of recommended calorie intakes, correcting for age and relative size, all of the increase in total protein intake was due to animal protein, vegetable protein remaining constant. Almost all of the increase in adequacy of total calories was due to increasing fat intakes, relatively much less to carbohydrate, and this only among the poor families. In this population, as more money becomes available to purchase food, there is an increase in animal protein and fat intakes, over an almost constant vegetable protein and carbohydrate intake. There is a simultaneous increase in consumption of fruits and vegetables, accounting for increases in the carotene and vitamin C intakes.

Adolescent↗
PubMed1981

Determinants of growth among poor children: effect of expenditure for food on nutrient sources.

The effect of increasing expenditure on the nature and the amounts of foods consumed by children from an urban population was estimated by studying the diets of 111 children from 20 typically poor families and those of 12 children from six economically better off families who had a much more satisfactory growth status. Total calories and protein, fat, and carbohydrate calories were expressed as a fraction of each individual's estimated energy requirement, thus adjusting for sex, age, and size. No important sex differences were found. Calorie intake was 87.2 +/- 17.3% and 111.4 +/- 18.1% of requirement for the two groups, respectively. Differences were found between the groups in protein calories which were totally due to milk and meat. Differences in fat calories were due to milk, meat, and separated fats. There was no significant difference between groups in total carbohydrate calories, although there were shifts in its components with increasing expenditure. Regression analysis of calorie adequacies as a function of per capita expenditure for food, both in the poorer group and in the combined population, were performed and yielded highly significant (p less than 0.001) results. These were due to significant gradual increases in the consumption of milk, meat, separated fats, fruits and vegetables on top of an almost constant consumption of the staple cereals, roots and tubers.

Child↗
PubMed1981

Fasting and postprandial plasma free amino acids of infants and children consuming exclusively potato protein.

Fasting and postprandial plasma free amino acids were studied in nine children on the 9th day of consumption of a diet in which potato protein provided all nitrogen at a marginal level of protein intake (5.03-5.10% protein-calories). The analysis of the potato utilized indicated that 49% of total amino acids (TAA) were free amino acids (AA) and 40% essential amino acids (EAA). Fasting values of TAA and total essential amino acids (TEAA) and the ratios of EAA/TEAA were similar to those obtained previously with milk or casein diets. The low percentage of protein-calories in the diet and relatively poor nitrogen absorption of the potato were reflected in a low (0.236) fasting TEAA/TAA ratio. Met/TEAA and Trp/TEAA ratios were significantly (P less than 0.05) but not markedly lower 3 hours postprandially compared to fasting values, returning to the initial levels 4 hours postprandially. Thr/TEAA ratio was significantly higher (p less than 0.05) at 3 hours but not so at 4 hours. The results suggest that potato protein has an adequate ratio of TEAA/TAA and the balance among individual EAA concentrations should be able to meet the EAA requirements of growing infants and small children if fed and absorbed in sufficient amounts to meet total nitrogen needs.

Amino Acids↗
PubMed1981

Prolonged consumption by infants of wheat-based diets with and without casein or lysine supplementation.

Infants consumed 75% of calories as 82% extraction wheat flour with satisfactory short-term protein and energy digestion. Protein needs, represented by N retentions from casein, probably were not satisfied. Long-term (3+ months) studies in four infants showed that 50% calories and 80% protein from wheat (casein added to 8% protein calories) supported weight gain and linear growth more than expected. Prolonged feeding of 75% calories and 100% protein from wheat attempted in three infants. In the oldest (15.5 months), digestibility and growth was satisfactory; in one, despite good digestion, weight gain and growth was inadequate and serum albumin fell until 0.2% lysine was added; and in another, weight gain was satisfactory but albumin fell to 3.25 g/dl and growth was inadequate. In six other infants, lysine addition during the 2nd of 3 months was associated with significant increase in N retention and weight gain and stabilization of albumin; lysine withdrawal resulted in significant decrease in weight gain with no effect on N retention or albumin; growth was barely adequate during 3-month study. Serum cholesterol fell only when dietary protein was inadequate. It is practically impossible for unsupplemented wheat to satisfy protein needs of infants and most small children.

Body Weight↗
PubMed1981

Prolonged consumption of potato-based diets by infants and small children.

A previous short-term study demonstrated that infants and children could consume diets in which 75% of energy and all protein was provided by the white potato. Nitrogen balance was inferior to casein control at this level or protein intake. Potato intake was limited by the bulk of the diets and the poor digestibility of carbohydrates. In the present study 10 children were offered diets containing 50%, 75% and 84.2% of total energy as potato (Solanum Tuberosum ssp. andigena) during a period of 3 months. Casein was added to the 50 and 75% diets to complete 8% of energy as protein (N X 6.25). Acceptability, tolerance, digestibility and growth of the children were analyzed. The 84.2% potato studies were aborted shortly after the beginning because of the excessively large volume. Acceptability and tolerance to the 50% potato diets were excellent but with the 75% potato diets were noted to decrease during the last days of the studies. Six of the eight children who completed the studies showed satisfactory weight gain and catch-up growth while maintaining normal serum albumin concentrations. In one other, weight gain was adequate but did not achieve catch-up growth, and in the youngest child weight gain and linear growth were inadequate. Metabolic balances did not show improvement or deterioration of digestibility throughout the study. Infants can consume up to 50-75% of energy and as much as 80% of their nitrogen requirements as potato if the remaining energy and nitrogen is provided by a non-bulky, easily digestible food.

Body Height↗
PubMed1981

[Digestibility and protein quality of quinua: comparative study of quinua (Chenopodium Quinoa) seed and flour in children].

Based on the hypothesis that the digestibility of quinua seed is the limiting factor in the utilization of nutrients from this staple, two quinua-based diets were prepared using quinua seeds and quinua flour. Theses diets were offered to children recovering from malnutrition. The digestibility and protein quality of the quinua diets were compared to those of a casein control diet by analyzing the children's metabolic balance. Results showed that digestibility of the quinua diets were compared to those of a casein control diet by analyzing the children's metabolic balance. Results showed that digestibility of the quinua seed is the limiting factor in the protein and energy utilization, and that milling improves significantly the digestibility of fat and carbohydrates. Findings also confirmed that the protein quality of quinua seeds is adequate for human consumption.

Body Weight↗
PubMed1981

Fecal 13C analysis for the detection and quantitation of intestinal malabsorption. Limits of detection and application to disorders of intestinal cholylglycine metabolism.

The use of 14CO2 breath tests and fecal analyses for the detection and quantitation of intestinal malabsorption has been extensively documented in adult subjects. The use of stable isotopes has extended the range of breath test applications to include pediatric and obstetric subjects. Here we report a fecal 13C analysis that can be used in conjunction with 13CO2 breath tests. Twenty-four-hour fecal samples were collected before and after the administration of a labeled substrate. The samples were homogenized and combusted to CO2, and the 13C abundance was determined by high-precision, differential isotope ratio mass spectrometry. The isotopic variation between successive 24 hr fecal samples was 0.6 0/00 (0.0006 atom percent). This variation limited the sensitivity of the fecal analysis to 13 mumol of 13C label per mold of fecal carbon. Simultaneous cholyglycine 13CO2 breath tests and fecal assays were performed in five children. One child with bacterial overgrowth had an abnormal breath test and a normal fecal test. Of three children with ileal dysfunction, only one had an abnormal breath test, whereas the fecal test was abnormal in all three, Both the breath test and fecal test were abnormal for a child who had undergone an ileal resection. Both tests were normal for a child with ulcerative colitis.

Adolescent↗
PubMed1980

Lactose intolerance.

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Adaptation, Physiological↗