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Biomedical subjects

G Arroyave

Publications and source records attributed to G Arroyave.

At least 19 recordsLinked to original sources
PubMed1995

Agricultural and food policies. Some concerns regarding their nutritional relevance.

In recent times, nutrition analysts have been emphasizing the fact that the most critical nutritional unfulfilled need in underdeveloped countries is energy or quantity of food. This has prompted some leading food economist and agricultural policy makers to promote the extensive cultivation of high field inexpensive staples, including starchy roots and tubers. A typical example is cassava in many African countries and Indonesia. These foods not only have very little and poor quality protein, but also lack other essential nutrients. Interestingly, underdeveloped populations seem to select the nutritionally poorest staples under condition of extreme economic constraints, for example cassava or sorghum. But as their economic level improves they switch to nutritionally better staples, like wheat or rice. The people seem to be able to < > the need for quality rather than simply quantity as soon as an improved economic status allows them more choices. Some examples are given to support this contention. The present analysis emphasizes that the goals and objectives of nutrition scientists must be integrated with those of food and agricultural economists for the design of agricultural policies with increased relevance to human nutrition in a comprehensive way. Rather than proposing the cultivation of one inexpensive staple, these policies should consider a variety of complementary foods which would allow the people to chose diets providing sufficient quantities and balance of all essential nutrients in addition to energy.

Agriculture↗
PubMed1993

[Food fortification with emphasis on the addition of micronutrients to wheat flour].

Nutrification of wheat flour with at least ten micronutrients has proven to be technologically feasible and nutritionally effective. Some criteria must be satisfied in order to determine if the food is appropriate as a carrier for nutrification in a country or in a particular region. The most important aspect however, is that to be sure that it is consumed by the population in need of preventive actions and control of specific vitamin and mineral deficiencies. In view of the fact that Latinamerican countries may greatly differ in this respect, such a question deserves careful scrutiny. The preliminary efforts and previous large scale trials in some countries, illustrate the most frequent problem: the main obstacle against successful achievement of many nutrification programs in the developing world has been, not the lack of technological and economical feasibility but he failure to take key decisions at political levels.

Flour↗
PubMed1988

[3 problem vitamins in Latin America].

The list of vitamins recognized as essential in human nutrition is extensive. Only some of them, however, are attributed an important role in public health. The present paper deals with three of these selected because their deficiencies still prevail in important sectors of population in the Latin American Region: vitamin A, vitamin C and vitamin D. For each vitamin the paper discusses the scientific bases for their requirements, as well as pragmatic considerations to be taken into account for the derivation of recommended dietary intakes. Reference is made to the logic of applying the concepts of nutrient density when developing guidelines for the design of diets for the family and the community. Adequate nutrient density means that when a diet is consumed in sufficient amounts to satisfy energy requirements, the needs for essential nutrients are also being met. For the above reasons, the principle of expressing the recommended levels of intake of vitamin A and C per 1,000 kilocalories has been followed. This is not the case with vitamin D which, in view of its special feature of being synthesized endogenously, is not really a vitamin in the strict sense of the term and, therefore, a rational and consistent relationship with the energy of the diet cannot be established.

Adolescent↗
PubMed1988

[Abuse of megadoses of vitamins].

There is no evidence of any nutritional benefit derived from the consumption of vitamin supplements in excess of the daily intakes recommended by the various international and national expert committees. Furthermore, in the case of certain of the vitamins such as vitamin A and vitamin D, excessive intakes result in toxic effects. To a lesser extent this is also the case for vitamin C and nicotinic acid. In addition, the use of high supplements or megadoses of any vitamin results in a wasteful misuse of economic resources. This reduces the capacity to acquire foods which would have clear nutritional benefits for the whole family. Consequently, the indiscriminate use of these megadoses must be discouraged. Their application is exclusively justified in clinical situations under direct medical supervision.

Adult↗
PubMed1983

Determination of vitamin A in blood. Some practical considerations on the time of collection of the specimens and the stability of the vitamin.

The stability of vitamin A and retinol-binding protein (RBP) in serum separated from the clot at different times after blood extraction and the effect of ingesting a vitamin A-rich breakfast on postprandial serum levels of retinol, carotenoids, and RBP were investigated. In the stability trials, venous blood was drawn from 12 well-nourished young adult subjects and sample aliquots were maintained, respectively, at 4 degree C or at room temperature (26 to 28 degrees C). The serum was separated from the clot either immediately after blood clotting or at 2, 4, 6, 12, and 24 h after blood extraction. Serum retinol and RBP were stable either at 4 degrees C or at room temperature, even if the serum was separated from the clot 24 h after blood extraction. In the breakfast experiment, seven young adult subjects ingested a meal containing 291 microgram of retinol equivalents. The serum levels of retinol, carotenoids, and RBP were measured pre- and postprandially up to a period of 4 h. The ingestion of the breakfast meal did not alter significantly the postprandial serum levels of retinol, carotenoids, or RBP. These results are of practical importance for the performance of vitamin A nutrition surveys involving field work, when as is common, blood specimens cannot be collected under fasting and, in addition, they have to be transported from far away localities to the laboratory.

Adult↗
PubMed1983

Lack of direct association between serum transferrin and serum biochemical indicators of vitamin A nutriture.

The association between serum transferrin and serum biochemical indicators of vitamin A and protein nutriture was investigated in 295 preschool children. Their levels of retinol and RBP correlated positively and significantly with transferrin, iron, total iron binding capacity (TIBC), total proteins and albumin. However, when removing those cases having unacceptable levels of total proteins (less than or equal to 6.4 g/dl) and/or albumin (less than or equal to 3.5 g/dl), the significant correlation between retinol (or RBP) and transferrin disappeared. It is concluded that transferrin levels are not directly related to the vitamin A nutritional status. The significance of this observation in relation to the known interaction between vitamin A and iron is discussed.

Blood Proteins↗
PubMed1982

The effect of vitamin A fortification of sugar on iron metabolism in preschool children in Guatemala.

The effect of improvement in vitamin A nutriture on biochemical indicators of iron nutrition during national vitamin A fortification of sugar was investigated longitudinally. Four "paired-comparison-subgroups" of preschoolers were studied before fortification (survey I) and, respectively, at 6 months (survey I versus II), at 1 yr (survey I versus III), at 1 1/2 yr (survey I versus IV), and at 2 yr (survey I versus V) after fortification began. Comparing I versus II gave a positive correlation (p less than 0.001) between changes in serum retinol or retinol-binding protein and changes in iron, total iron binding capacity, and percentage transferrin saturation. In contrast, changes in serum ferritin correlated negatively (p less than 0.05). Comparing V with I, retinol, retinol-binding protein, iron, and percentage transferritin saturation increased, but ferritin also increased (p less than 0.05). Consequently, the distribution of serum iron and ferritin values of the children improved (p less than 0.05). Because dietary iron did not change through the study period, the results suggest that vitamin A fortification had a favorable effect on iron metabolism and nutritional status.

Child, Preschool↗
PubMed1981

The effect of vitamin A fortification of sugar on the serum vitamin A levels of preschool Guatemalan children: a longitudinal evaluation.

Based on the Guatemalan program of vitamin A fortification of sugar, a longitudinal evaluation on serum retinol levels of preschool-aged children was performed. Five consecutive surveys executed every 6 months were examined, considering only children who were surveyed more than once. Thus, the changes in their serum retinol after the intervention were evaluated. Natural dietary vitamin A remained unchanged throughout. Addition of retinyl palmitate to sugar increased significantly the intake (p < 0.001). After 1 yr of fortification 76% of the children experienced an elevation of retinol. All those with initial values < 20 microgram/dl showed an increase. Mean values increased significantly, particularly for children below 20 microgram/dl whose levels changed from 16.2 +/- 2.9 to 30.2 +/- 9.7 (P < 0.00001). Those between 20 to 29 microgram/dl increased from 24.9 +/- 3.2 to 30.1 +/- 8.1 (p < 0.0003). Similar results were obtained after 2 yr. The results indicated the effectiveness of the program in raising serum retinol levels.

Child, Preschool↗
PubMed1981

[Dietetic study of pregnant women of Santa Maria Cauqué, Guatemala. I. Variability of protein indicators and analysis by the time of meals].

The distribution of the protein energy ratio indicators (Pe%), amino acid score and protein value (NDpCal%) in the three daily meals (breakfast, lunch and dinner) of the diet of pregnant women from Santa María Cauqué, Guatemala, was studied. The results were compared with those obtained for the total daily food intake. The differences observed were not significant, confirming the validity of the determination of amino acid score, Pe% and NDpCal% in the foods consumed during the whole day in this type of populations. It also reflects the nutritional benefit of the food pattern, since protein utilization would not be decreased by a different distribution of protein quality and concentration throughout the three daily meals. The variability among individuals of Pe% intake, amino acid score and NDpCal% gave the following values: 16.0, 9.3 and 15.6, respectively. It is noteworthy to add that the variability of Pe% observed is similar to that reported for populations of developed countries.

Amino Acids↗
PubMed1979

alpha 2-Macroglobulin in vitamin A-deficient children.

Serum samples were obtained from 43 children 14 years old or younger in Malaysia and Guatemala. The levels of the serum glycoprotein alpha 2-macroglobulin (alpha 2-M) were assayed by two methods: the trypsin-binding assay of Ganrot (Clin. Chim. Acta 14:493, 1960) and a radial immunodiffusion assay against alpha 2-M antiserum. The two methods gave the same results. When serum alpha 2-M levels were plotted against serum vitamin A concentrations, they were significantly correlated (r = 0.505, P less than 0.001); children with serum vitamin A levels greater than 40 micrograms/100 ml had alpha 2-M levels of 3.71 +/- 0.79 mg/ml (mean +/- SD, n = 13), while those with level less than 40 micrograms/100 ml had alpha 2-M levels of 2.78 +/- 0.51 mg/ml (n = 30); the difference was significant (P less than 0.001). Normal, apparently healthy children had alpha 2-M levels of 3.90 +/- 0.39 mg/ml. Most of the children sampled suffered from a variety of infections; of these, measles appeared to counteract the effect of vitamin A deficiency by elevating alpha 2-M levels. Vitamin A-deficient children with measles had alpha 2-M levels not significantly lower than those of normal children. The difference between deficient and normal values of alpha 2-M was still significant (P less than 0.05) when expressed per milligram of serum protein, showing that the effect was not caused by lowered serum protein concentrations associated with protein-calorie malnutrition, from which most of the deficiency children suffered.

Adolescent↗
PubMed1979

[Relation of the energy content of fats and proteins as an indicator of energy-protein potential of population diets].

The protein-calorie (Po/o) and the protein value (NDpCalo/o) have been proposed as indices to evaluate the potentiality of diets to meet protein and calorie needs of a given population. The fat-calorie to protein-calorie ratio (G/P) is presented as a complementary index, considering the possibility that the values of Po/o and NDpCalo/o can be adequate but that the energy density of the diets is too low, as might be the case in many rural communities of the developing countries. On the basis of the evidence discussed in this paper, the G/P ratio estimated as adequate is 2.5, and values lower than 2 can be considered as nutritionally unacceptable.

Child, Preschool↗
PubMed1979

[Decrease in serum levels of retinol and its binding protein (RBP) in infection].

The main purpose of the present study was to determine the qualitative and quantiative effect of various infectious epsiodes on the blood serum levels of retinol and retinol-binding protein (RBP). Twenty-four children and 30 adult subjects were studied. The infections studied included chickenpox (n = 7); bronchitis (n = 9) upper respiratory infection (n = 30); tonsillitis (n = 2); diarrhea (n = 2) and one case each of: febrile stomatitis, nonspecific gastrointestinal alteration, urinary infection and shigellosis. In addition to retinol and RBP, the study determined changes in serum carotene, proteins, albumin and globulins. The results clearly demonstrate the marked depressing effect of infections on serum retinol, with a magnitude which in many cases reached more than 20 micrograms/dl, and in others more than 30 micrograms/dl. The RBP levels were significantly correlated with retinol, decreasing proportionally with infection. Serum albumin also decreased in most instances; and the globulin levels of the children, but not of the adults, were significantly higher during the infections. Carotene did not show important variations. The effects were more intense when fever accompanied the infectious episodes. These results are considered of great public health significance, in view of the large majorities, mainly children, who ordinarily subsist with very low serum retinol levels in the underdeveloped regions of the world. As infections attack these underpriviledged children, their serum retinol and RBP levels will likely drop a magnitude similar to that observed in the subjects of this study. They may then reach even more critically deficient retinol levels and be in serious danger of developing a severe acute state of clinical vitamin A deficiency.

Adolescent↗