Zinc, calcium, and magnesium concentrations in milk from American and Egyptian women throughout the first 6 months of lactation.

Effects of stage of lactation, nutrient intake, and cultural differences on the composition of human milk were examined during the first 6 mo of lactation in American and Egyptian women. In both population groups zinc levels in milk decreased from 1 to 6 months of lactation. American women supplemented with Zn had higher levels of Zn in their milk than did unsupplemented American or Egyptian women. Concentrations of calcium and magnesium were not significantly different in milk of American and Egyptian women except at month 6 of lactation. Ca levels in milk of both population groups increased from 1 to 2-3 mo of lactation and then decreased at 6 mo; Mg concentrations increased from 1 to 3 mo and then reached a plateau. Similarities in the longitudinal decrease observed in Zn levels of milk in Zn supplemented and unsupplemented subjects suggested physiological regulation.

Determinants of pregnancy outcome and newborn behavior of a semirural Egyptian population.

Several potential determinants of birth weight and neonatal behavioral organization, ie, maternal anthropometry, food intake (energy, protein, and plant- and animal-source foods), morbidity, and household socioeconomic status, were followed systematically in a semirural Egyptian population during greater than or equal to 6 mo of pregnancy. In early pregnancy mothers were generally normal weight to moderately overweight. Their mean energy intake, largely from plant sources, was approximately 8.37 MJ/d (2000 kcal/d) during trimesters 2 and 3. Early (3 mo) pregnancy weight and weight gain during trimesters 2 and 3 were significantly positively related to birth weight Z scores. The best predictor model examined for birth weight included early pregnancy weight, weight gain, and length of gestation (R2 = 0.45). Early pregnancy weight and maternal intake of animal-source foods were significant positive predictors of the newborn's orientation and habituation behavior, respectively. Habituation and orientation measures assess the infant's early ability to process information.

Vitamin B-6 status of Egyptian mothers: relation to infant behavior and maternal-infant interactions.

Functional consequences of marginal maternal vitamin B-6 status for behavior of the neonate and for mother-infant interactions at age 3-6 mo were assessed by a double-blind procedure. In 27 of 70 Egyptian village women studied, vitamin B-6 concentration of their milk was considered indicative of poor maternal vitamin B-6 nutriture. Neonatal behavior, quantified by the Brazelton Neonatal Behavioral Assessment Scale, showed that consolability, appropriate build-up to a crying state, and response to aversive stimuli were significantly correlated with maternal vitamin B-6 nutriture. Naturalistic observational procedures, used twice monthly with infants aged 3-6 mo, indicated that mothers assessed as having marginal vitamin B-6 status were less responsive to their infants' vocalizations, showed less effective intervention to infant distress, and were more likely to use older siblings as care-givers than were mothers of better vitamin status. We conclude that vitamin B-6 was a factor influencing both the behavior of the mother and her infant.

Blood urea content for evaluating dietary protein quality.

The protein quality of broad beans was evaluated by using three different methods: the net protein ratio (NPR), the net protein utilization (NPU) and the relative protein value (RPV). Casein was used as a reference protein. The relationship between the values obtained on rats by each method and serum urea concentrations were examined. Serum urea concentration increased by increasing the dietary protein content. It showed a positive correlation of 0.70 and 0.60 for broad beans and casein respectively. NPR values increased by decreasing the level of dietary protein. There was no relationship between the NPR and the serum urea contents in animals fed the casein and broad bean diets. The NPU values indicated that protein utilization was greatest at low dietary protein levels and decreases by increasing the protein content of diet. Serum urea concentration showed an inverse proportion with the NPU values. This was demonstrated by correlations of -0.67 and -0.75 for broad beans and casein respectively. The highest RPV for broad beans was obtained by using the change in body water and the lowest by using the change in body nitrogen as a response parameter. An inverse relationship exists between serum urea concentration and the RPV for broad beans.

Detoxification and nutritional evaluation of solvent extracted Egyptian cottonseed meal.

Attempts for degossypolization of the solvent extracted Egyptian cottonseed meal (CSM) and evaluation of its nutritional value as a possible protein supplement for human feeding were undertaken. Three methods were applied for degossypolization: Steaming, addition of iron(II)-sulphate dihydrate, and steaming after addition of iron(II)-sulphate dihydrate. Steaming was done for varying periods of time. Nutritional evaluation was undertaken by chemical analysis and by feeding experiments. Chemically, the third method for degossypolization was the most effective. Feed efficiency and protein efficiency for diets containing 15 and 10% levels of CSM protein indicated that all treatments used for detoxification caused a decrease in diet and protein quality. Diets containing iron-supplemented CSM at the same level were the best of all. Mixing CSM with casein to form a diet containing 10% protein increases the protein quality of both casein and CSM.

Nutritive value of some common Egyptian meals.

The protein quality of two common Egyptian meals namely lentils and "Koshari" was evaluated on rats by utilizing the net protein ratio (NPR), the relative protein value (RPV) and the serum urea content methods. Casein was used as a reference protein. The macro nutrient contents of the two meals are almost similar. The NPR is higher with low dietary protein level. The estimated RNV of the "Koshari" was higher than that of lentils. Lower serum urea levels were found with the "Koshari" than with lentils meal indicating its better protein quality. This is most probably due to the effect of amino acid supplementation of cereals and legumes. Results obtained are in favour of utilizing the serum urea content method as a simple and reliable one for evaluating protein quality since a negative relationship exists between blood urea content and the biological value of dietary protein. Its validity in estimating dietary protein quality in man need to be investigated.

Availability of essential amino acids in corn flour and corn bread.

The availability of nitrogen, lysine and 9 essential amino acids was determined in corn before and after baking. Lysine availability was determined by the growth response method on weaning rats using regression analysis of body weight gain or moisture gain against lysine consumed from corn flour and corn bread. The results show a high correlation between lysine consumed and weight gain or moisture gain (r = 0.95) for rats fed the standard diets for 3 weeks. A good correlation was also obtained for corn bread. The results of lysine availability show that baking greatly improves availability by both ways of calculation. The availability of nitrogen and essential amino acids were also investigated by the balance trials with rats. Results show that availability values for nitrogen and all amino acids except threonine increased by baking. Data for food intake, weight gain, food efficiency, PER, NPR and true digestibility revealed that baking had little or no effect on nutritive value of corn tested in this investigation.

Nutritive value of meat-soy mixture.

The protein value of meat soy blend was evaluated by utilizing the net protein ratio (NPR), the relative protein value (RPV) and the serum urea content methods. It was compared with that of meat. Casein was used as a reference protein. NPR values indicated that utilization of meat and meat soy proteins are comparable. The study of amino acid pattern shows that sulphur containing amino acids are limiting to almost the same degree in meat and meat soy blend. However, the RPV of meat soy bean blend is slightly higher than that of meat. The lowest serum urea content was that of rats fed meat soy blend. Therefore, the mixing of meat with soy bean did not reduce the nutritive value of meat, on the contrary there is tendency towards improvement.

The response of adult rats to varying combinations of dietary lysine and threonine.

The response of adult rats fed diets containing amino acid mixtures with varying combinations of lysine and threonine was studied by estimating the change in body weights, organ weights, total nitrogen content of organs and the concentration of free plasma lysine and threonine. Analysis of variance indicates a significant effect of threonine, lysine and a significant interaction due to feeding the two amino acids on the body weights, organ weights and total nitrogen content of various organs. Significant effect on the level of the plasma free amino acid was also shown as a result of feeding the particular amino acid. Results show that in deficient animals the rates of building body protein are low but are higher in the lysine deficient animals than in the threonine deficient and protein deficient animals. The varying rates of exchanging protein between the various organs in response to changing the levels of amino acids in the diet would mean that total change in body protein or total nitrogen balance may not be satisfactory way to determine the protein or amino acid requirements for maintenance. It seems to be necessary to focus down on protein turnover rates in specific tissues.

Response of adult rats to lysine supplementation.

The response of adult rats to wheat flour protein fortified by addition of lysine was studied by utilizing the relative protein value (RPV) compared to non-fortified wheat flour. Lactalbumin was used as a standard protein. Fortification of wheat flour by 0.3% lysine resulted in better growth of rats when fed at 6% protein level. However, no significant difference was observed in the growth of rats fed non-fortified or fortified wheat flour at 4% or 2% protein level. The relative nutritive value (RNV) of supplemented wheat flour protein is higher than that of the non-supplemented when change in body weight or change in body water are used as response parameters. When the dietary protein is provided at maintenance or below maintenance levels, lysine is not limiting. Therefore, supplementation of wheat flour protein with lysine did not result in any better growth response. When protein is provided at levels above maintenance requirements lysine is limiting and better growth was achieved by lysine supplementation to wheat flour protein.