[Conclusions and recommendations of a WHO expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas]. / Conclusions et recommandations à l'issue de la consultation de l'OMS sur la lutte contre la carence martiale chez le nourrisson et le jeune enfant dans les pays d'endémie palustre.

This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic.

Risks of iodine-induced hyperthyroidism after correction of iodine deficiency by iodized salt.

Biochemical signs of hyperthyroidism, or even overt and possibly lethal clinical hyperthyroidism were reported in 2 severely iodine-deficient African countries (Zimbabwe and Democratic Republic of Congo, RDC) soon after the introduction of iodized salt. The 2 countries had access to iodized salt produced in Botswana, as well as 5 other countries in the region, namely Cameroon, Nigeria, Kenya, Tanzania, and Zambia. Therefore, a multicenter study was conducted in these 7 countries to evaluate whether the occurrence of iodine-induced hyperthyroidism (IIH) after the introduction of iodized salt was a general phenomenon or corresponded to specific local situations in the 2 affected countries. Two or 3 areas with a past history of severe iodine deficiency that had recently been supplemented with iodized salt were selected in each of the 7 countries. The prevalence of goiter was determined in 4423 schoolchildren in these areas and the concentration of urinary iodine in 2258. Salt factories and health structures were visited for the evaluation of the quality of iodized salt and the possible occurrence of IIH. The study showed that iodine deficiency had been eliminated in all areas investigated, and that the prevalence of goiter had markedly decreased since the introduction of iodized salt. This is a remarkable achievement in terms of public health. However, some areas were now exposed to iodine excess due mostly to a poor monitoring of the quality of the iodized salt and of the iodine intake of the population. In these areas or countries, IIH occurred only when the introduction of iodized salt had been of recent onset (<2 years), namely in Zimbabwe and RDC. In conclusion, the risk of IIH after correction of iodine deficiency is closely related to a recent excessive increment of iodine supply.

Iodine deficiency in the world: where do we stand at the turn of the century?

Iodine deficiency is the leading cause of preventable mental retardation. Universal salt iodization (USI), calling for all salt used in agriculture, food processing, catering and household to be iodized, is the agreed strategy for achieving iodine sufficiency. This article reviews published information on programs for the sustainable elimination of the iodine deficiency disorders and reports new data on monitoring and impact of salt iodization programs at the population level. Currently, 68% of households from areas of the world with previous iodine deficiency have access to iodized salt, compared to less than 10% a decade ago. This great achievement, a public health success unprecedented in the field of noncommunicable diseases, must be better recognized by the health sector, including thyroidologists. On the other hand, the managers and sponsors of programs of iodized salt must appreciate the continuing need for greatly improved monitoring and quality control. For example, partnership evaluation of iodine nutrition using the ThyroMobil model in 35,223 schoolchildren at 378 sites of 28 countries has shown that many previously iodine deficient parts of the world now have median urinary iodine concentrations well above 300 microg/L, which is excessive and carries the risk of adverse health consequences. The elimination of iodine deficiency is within reach but major additional efforts are required to cover the whole population at risk and to ensure quality control and sustainability.

Meeting the challenges of micronutrient deficiencies in emergency-affected populations.

Micronutrient deficiencies occur frequently in refugee and displaced populations. These deficiency diseases include, in addition to the most common Fe and vitamin A deficiencies, scurvy (vitamin C deficiency), pellagra (niacin and/or tryptophan deficiency) and beriberi (thiamin deficiency), which are not seen frequently in non-emergency-affected populations. The main causes of the outbreaks have been inadequate food rations given to populations dependent on food aid. There is no universal solution to the problem of micronutrient deficiencies, and not all interventions to prevent the deficiency diseases are feasible in every emergency setting. The preferred way of preventing these micronutrient deficiencies would be by securing dietary diversification through the provision of vegetables, fruit and pulses, which may not be a feasible strategy, especially in the initial phase of a relief operation. The one basic emergency strategy has been to include a fortified blended cereal in the ration of all food-aid-dependent populations (United Nations High Commissioner for Refugees/World Food Programme, 1997). In situations where the emergency-affected population has access to markets, recommendations have been to increase the general ration to encourage the sale and/or barter of a portion of the ration in exchange for locally-available fruit and vegetables (World Health Organization, 1999a,b, 2000). Promotion of home gardens as well as promotion of local trading are recommended longer-term options aiming at the self-sufficiency of emergency-affected households. The provision of fortified blended foods in the general ration has successfully prevented and controlled micronutrient deficiencies in various emergency settings. However, the strategy of relying only on fortified blended foods to prevent micronutrient deficiencies should be reviewed in the light of recurring evidence that provision of adequate supplies of these foods is often problematic. Donor policies on the bartering or exchange of food aid should also be clarified. Furthermore, the establishment of micronutrient surveillance systems, including standardized micronutrient deficiency diagnostic criteria, are vital for the control of micronutrient deficiency diseases.

Polio as a platform: using national immunization days to deliver vitamin A supplements.

In 1988 the 41st World Health Assembly committed WHO to the goal of global eradication of poliomyelitis by 2000 "in ways which strengthen national immunization programmes and health infrastructure". The successful use of polio National Immunization Days (NIDs) to deliver vitamin A is an example of how polio eradication can serve as a platform to address other problems of child health. Importantly, this integration is helping to achieve the World Summit for Children goal of eliminating vitamin A deficiency by the year 2000. It is estimated that between 140 million and 250 million preschool children are at risk of subclinical vitamin A deficiency. In 1998 more than 60 million children at risk received vitamin A supplements during polio national immunization days (NIDs). While food fortification and dietary approaches are fundamental to combating vitamin A deficiency, the administration of vitamin A supplements during NIDs helps raise awareness, enhance technical capacity, improve assessment and establish a reporting system. Moreover, polio NIDs provide an entry point for the sustainable provision of vitamin A supplements with routine immunization services and demonstrate how immunization campaigns can be used for the delivery of other preventive health services.

Calorimetric evaluation of the diary-respirometer technique for the field measurement of the 24-hour energy expenditure.

The results of measuring the 24-h energy expenditure by the diary-respirometer technique (factorial method) have been compared to those obtained by direct measurement of heat output and continuous recording of oxygen consumption and carbon dioxide production. Anthropometric and skinfold measurements were used to estimate lean body mass in eight male Asian subjects. They remained for 36 h in a metabolic chamber wearing a calorimeter suit. A ventilated hood and differential gas analysers were used to measure oxygen consumption and carbon dioxide production. While the subjects were sitting inactive, the KM respirometer indicated a mean energy expenditure which was significantly lower than with the calorimeter suit or with the ventilated hood. During exercise on an ergometer at 25 W and 75 W the respirometer gave readings of energy expenditure which were also significantly lower than either the ventilated hood or the calorimeter suit. The daily energy expenditure expressed in MJ for a standard body weight of 60 kg (MJ/60 kg) measured from the calorimeter suit was 9.79 MJ; from the ventilated hood, 9.51 MJ; from the diary-respirometer method, 8.30 MJ. The mean energy intake, measured for 10 consecutive d after the the subjects had left the metabolic room was 7.87 MJ, while during their stay in the metabolic room, their spontaneous intake was 7.74 MJ. The diary-respirometer technique tends to cumulate the errors from an incorrect time and motion recording and the potential lack of representativeness of the measurement of the energy cost of the activities. In the present study, it seems that the discrepancy observed between the results of the different methods can be attributed almost entirely to the underestimation of the energy cost of the activities by the respirometer. Contrary to our expectation the diary-respirometer technique does not seem to overestimate systematically the daily energy expenditure.

Whole-body protein turnover in man determined in three hours with oral or intravenous 15N-glycine and enrichment in urinary ammonia.

Studies were carried out in eight normal adults to simplify the continuous infusion-end product method for measuring whole-body protein turnover using 15N-glycine. When a priming dose of label suitable for the urea pool was followed by intermittent oral doses of label, plateau enrichment was maintained in urinary urea and ammonia from 9 to 18 h, giving values for nitrogen flux (18 h) of 0.69 +/- 0.05 g N/kg/d with urea and 0.46 +/- 0.01 g N/kg/d with ammonia. With a priming dose appropriate for the ammonia pool, plateau was reached in urinary ammonia in less than 120 min and maintained for up to 6 h. Nitrogen flux (3 h) with oral 15N-glycine was 0.96 +/- 0.12 g N/kg/d, and with intravenous label was 0.61 +/- 0.13 g N/kg/d. There was a significant linear relationship between flux measured with oral and intravenous isotope. It is suggested that different components of protein turnover are measured with the different approaches, and that the short method in particular measures rapidly turning over proteins associated with the gastrointestinal tract.

The excretion of 5-oxoproline in urine, as an index of glycine status, during normal pregnancy.

The urinary excretion of 5-oxoproline, which may be used as an index of glycine status, was investigated in 30 normal pregnant women during different stages of pregnancy and in 18 non-pregnant female volunteers. During an 18-h study there was little variation in the 5-oxoproline/creatinine index, and a single sample gave a representative value. The excretion of 5-oxoproline/creatinine (mumol/mmol) rose progressively as pregnancy advanced (non-pregnant mean 10, SD 5, first trimester mean 46, SD 12, second trimester mean 150, SD 180, and third trimester mean 280, SD 320) and by the third trimester was over 20 times greater than in non-pregnant women. The data suggest that as pregnancy advances the endogenous production of glycine may be insufficient to satisfy the increasing demands.

The measurement of whole body protein turnover in the preterm infant with intragastric infusion of L-[1-13C]leucine and sampling of the urinary leucine pool.

The measurement of whole body protein turnover in the preterm infant has been investigated with an intragastric infusion of L-[1-13C]-leucine and with sampling of the urinary leucine pool. Measurements have been made in seven preterm infants with body weights averaging 1733 g, fed with either human breast milk (n = 3) or proprietary formulae (n = 4), giving intakes of 541 (+/- 25) kJ/kg and 465 (+/- 42) mg of N day-1 kg-1 and growing satisfactorily (14.7 +/- 2.6 g day-1 kg-1). The measurement of the enrichment of urinary leucine was well within the capability of gas chromatography-spectrometry, and similar values for the enrichment of plasma and urinary leucine were observed (plasma/urinary ratio was 0.93 +/- 0.04, mean +/- 1 SEM, n = 13). Isotopic equilibrium, as indicated by a plateau in the urinary leucine and expired CO2 enrichment, was obtained within 8 h and was maintained for at least 48 h. Nitrogen retention, measured by nitrogen balance, was similar to that calculated from the leucine retention (determined as the leucine intake--oxidation), i.e. 310 +/- 45 and 301 +/- 38 mg of N day-1 kg-1 (means +/- 1 SEM). Because of this it is suggested that in this specific type of study the direct measurement of nitrogen retention dispenses with the need for measurement of leucine oxidation, thereby simplifying the measurements. From the leucine flux, leucine intake and nitrogen retention, rates of whole body protein synthesis and degradation were shown to be 11.32 (+/- 0.78) and 9.54 (+/- 0.55) g day-1 kg-1.

Whole-body protein turnover in Jamaican women during normal pregnancy.

A cross-sectional study was carried out among 18 Jamaican pregnant women divided into three groups of 6 subjects according to the stage of pregnancy: group B, 12 weeks, group C, 24 weeks and group D, 33 weeks. A group (group A) of 6 non-pregnant women was selected as control. The rate of whole-body protein turnover was measured by continuous oral administration of 15N-glycine and the resting metabolic rate by the open-circuit method. All subjects had a normal pregnancy outcome. The composition of the diet on the day of the study was comparable between the four groups (approximately 80 g protein and 9.45 MJ energy) and not significantly different from the composition of the diet during the 2 d prior to the experiment. The rates of protein synthesis and breakdown were higher in groups B and C compared to group A and lower in group D where they reached values slightly higher than in group A. Estimated from urea enrichment, these rates did not vary significantly among the groups, while estimated from ammonia enrichment the difference was significant (P less than 0.05) and there was a negative correlation between the gestational age and the rate of synthesis (r = -0.63) and breakdown (r = -0.69). Nitrogen retention was comparable between the three groups of pregnant women and significantly higher than in the group A. The resting metabolic rate was similar between the groups of pregnant women. These results suggest that the rates of protein turnover observed during gestation reflect more the changes that occur in maternal than those in fetal tissues. The values for protein synthesis and nitrogen retention indicate that the amount of protein deposited during pregnancy is greater than that expected on the basis of body composition analysis. It is also suggested that as pregnancy proceeds whole-body protein turnover represents a smaller part of the resting metabolic rate.

Complementary food supplements to achieve micronutrient adequacy for infants and young children.

Many children in developing countries survive on a nutritionally inadequate diet. Dietary inadequacies during the complementary feeding period can be prevented by using complementary food supplements (CFSs) such as water dispersible or crushable micronutrient tablets, micronutrient sprinkles added to food just before feeding, or fortified spreads added to food just before feeding or fed as a snacks. A meeting was convened to discuss technical and operational issues related to the development of these new approaches and to identify knowledge gaps. The technical issues covered: what micronutrients to include, tolerable upper intake limits, bioavailability, micronutrient and macronutrient stability, package systems and amounts, encapsulation technologies, methods to limit or eliminate allergens, bacterial and chemical contamination, interactions between CFSs and complementary foods, and flavoring agents. Operational issues included: identifying the market positioning of CFSs, cost positioning of CFSs, regulatory requirements, CFS production and technology transfer, quality assurance, and public-private sector partnership and coordination. Intervention trials are needed to determine the efficacy of CFSs in preventing micronutrient deficiencies. Other important knowledge gaps relate to technical and operational issues. Sprinkles and tablets are produced using well-known technologies, but further research is needed to modify them for use as CFSs. Spread development is not as advanced as sprinkle and tablet development, and further research is needed to improve the technology. Although none of the products is ready for widespread use, enough information is available to set research priorities and accelerate product development and implementation.