Nutritional and Health-Related Environmental Studies (NAHRES)

Doctoral CRP on stable isotope techniques to assess intake of human milk and body composition of infants and young children up to 2 years of age.

Brief summary

Exclusive breastfeeding for 6 months, followed by the introduction of appropriate complementary foods and continued breastfeeding, as recommended by the World Health Organization and UNICEF (1), are cornerstones in infant nutrition. However, only limited information is available on the quantities of human milk consumed and the time of introduction of other foods into the infants’ diet, in particular in developing countries. The lack of information is, at least partly, due to the difficulties involved in measuring intake of human milk. By conventional technique, infants are weighed before and after each feed, “test weighing”. This technique is obviously time consuming and may disturb the normal feeding pattern. These practical problems can be overcome by using a stable isotope technique, the deuterium-oxide turnover method, as the normal feeding pattern is not influenced and the total volume of human milk, consumed by the baby over a period of 14 days, is measured. In addition, information about whether the infant has consumed water from other sources than human milk (representing intake of complementary foods or fluids) and the lactating mother’s body composition can be assessed based on total body water content. Furthermore, stable isotope technique can be used to evaluate the influence of feeding patterns on body composition of children during the first 2 years of life to contribute new information on the link between infant feeding and later risk of ill health.
The overall aim of this CRP is to contribute new information on infant feeding practices and the influence of early feeding on body composition of young children in different settings. This CRP has a strong focus on training and education and will contribute to capacity building in nuclear techniques in nutrition by training of PhD students in developing countries.

Background

The developing world is confronted by the double burden of malnutrition, i.e., the coexistence of under- and over-nutrition (2). The most vulnerable population groups include mothers and their infants and young children. Despite the widespread recognition that nutrition is a major risk factor for ill health (3), nutrition has recently been identified as one of the most neglected aspects of maternal, newborn, and child health (4). Early in life, the structure and function of the body underpins both short- and longer-term health outcomes. The crucial time during which the biology of physical growth and development can be most influenced by nutrition (either positively or negatively), encompasses pregnancy and the first two years of life (5, 6). This period has recently been referred to as the “1000 day window of opportunity” (http://www.thousanddays.org/) to stress the importance of investments in maternal and child nutrition and to emphasize that nutrition interventions during this window provide the best opportunity for prevention of longer-term consequences of early under-nutrition.

Infant feeding practices

Exclusive breastfeeding for 6 months, followed by the introduction of appropriate complementary foods and continued breastfeeding, as recommended by the World Health Organization and UNICEF (1), are cornerstones in infant nutrition. One of the significant missing links in knowledge regarding infant nutrition and health is quality data on feeding practices, i.e., data on breastfeeding duration and quantitative measures of milk intake and the time of introduction of complementary foods during the first 2 years of life. Inappropriate infant and young child feeding practices represent a major cause of malnutrition (7) and, unfortunately, in many settings, rates of exclusive breastfeeding are low and linked with early introduction of complementary foods (8). The importance of appropriate feeding practices during early life cannot be underestimated as exclusive breastfeeding has been associated with better short- and long-term health outcomes, including protection against obesity and related metabolic problems (9, 10).

The lack of information of infant feeding practices is, at least partly, due to the difficulties involved in measuring intake of human milk. By conventional technique, infants are weighed before and after each feed, often referred to as “test weighing”. This technique is obviously time consuming and may disturb the normal feeding pattern. In addition, in many settings, infants are nursed frequently - “on demand” - including during the night, resulting in severe practical limitations to the use of this methodology. By using a stable isotope technique, these practical problems can be overcome as the normal feeding pattern is not influenced and the total volume of human milk, consumed by the baby over a period of 14 days, is measured. Furthermore, the method is non-invasive as the dose of deuterium-oxide is consumed orally by the mother and only samples of urine or saliva are collected for analysis. Information about whether the infant has consumed water from other sources than human milk, indicating intake of complementary foods and/or fluids, can be obtained at the same time and the mother’s total body water content can be measured for body composition assessment. This method, elegant in its simplicity, is currently used in Member States with technical assistance from the IAEA (11).


Body composition to monitor the quality of growth of infants and young children

There is now strong evidence that growth from conception to 2 years of age represents a critical “window of opportunity” in terms of later risk of ill-health and is central to the concept of the developmental origins of adult disease (12). However, the assessment of growth during this crucial period of early vulnerability is largely based on anthropometric measurements such as body weight, with insufficient attention to the quality of growth and the relative partitioning of nutrients to fat-free mass (FFM) or fat mass (FM). At attended delivery, birth weight, length and head circumference might be measured as major indicators of pregnancy outcome and growth during infancy and childhood, comparing measurements against the recently launched WHO Growth Standards (13, 14). However, infants of similar weight, height or even weight for height can vary substantially in body composition. For example, Indian babies have been characterised as having the thin-fat phenotype because although small and thin at birth they have proportionally more body fat and centrally deposited fat than European newborns (15). This difference in body composition phenotype appears to be related to birth size and marks a fundamental metabolic difference and greater risk of later non-communicable diseases during adult life (16). These observations emphasise the importance of more detailed characterisation of body structure and composition to identify high risk of poor health at an early age (17).

Body weight is a simple and informative measurement with which to mark adequate nutrition and short term risk, for example as used as the basis for the first Millennium Development Goal of halving the proportion of underweight children by 2015 (http://www.un.org/millenniumgoals/). However, weight alone does not adequately reflect risks in the longer term of poor child growth and its consequences on health and development. For many countries in transition, improvements in child weight have taken place without improvements in linear growth with the result that if height is measured, normal weight children are increasingly identified as short and relatively fat (18, 19). Again this raises concern about the “quality of growth” and the implications for poor metabolic regulation and risk of later ill-health. These observations highlight the importance of reliable measurements of length/height at the same time as body weight, to better define healthy growth. The inclusion of length/height, and interpretation against the WHO Growth Standards should be encouraged in the assessment of the growth of infants and children as an integral component of the characterisation of healthy growth.

However, it is clear that even though good measurements of height and weight provide useful information, there is an urgent need to better capture the dynamic nature of growth during early life by assessment of body composition i.e., the partitioning of FM and FFM. The assessment of body composition is important in the short term in relation to the quality of diets used in the prevention and treatment of moderate and severely malnourished children, and to optimise intervention strategies (20). The reliable measurement of body composition during early life represents a technically challenging area to be addressed within this CRP by stable isotope dilution technique for total body water (TBW) assessment and other appropriate methodologies such as air-displacement plethysmography (ADP; PEA POD®) and/or Dual-Energy X-ray Absorptiometry (DXA) (21). Standardisation of TBW and DXA has been initiated by the IAEA for adults and older children (22, 23, 24, 25) and will be further specified for applications in newborns and children up to 2 years of age in a forthcoming document.

In summary; Improved infant feeding practices represents a high priority area in nutrition and health globally. In order to move this agenda forward, detailed information on feeding practices in different settings is needed, in particular information about breastfeeding and the introduction of complementary foods. The use of stable isotope technique to assess human milk intake as well as intake of water from other sources represent a unique opportunity to collect much needed information and to contribute to capacity building in this priority area.


Analytical techniques to be used

Stable isotope techniques will be used to 1) estimate intake of human milk and intake of water from other sources in breastfed infants (dose-to-mother method) and 2) total body water for the assessment of body composition in lactating mothers and young children. Analyses of stable isotope ratios in saliva or urine samples will be made by Fourier Transform Infrared spectrometry (FTIR), or where available, Isotope Ratio Mass Spectrometry (IRMS).


Objective
Overall objective

The overall objective is to contribute new information on infant feeding practices and body composition of infants and young children during the first 2 years of life.

Specific research objective (purpose)

The Doctoral CRP intends to:

  • GAssess feeding practices by stable isotope techniques in infants and young children (0-2 years) in different settings
  • Assess body composition of lactating mothers by stable isotope technique
  • Assess body composition of young children by stable isotope technique and other appropriate techniques
  • Contribute to capacity building in nutrition by supporting PhD students

Expected research outputs
  • New data on infant feeding practices
  • New data on body composition of lactating mothers and the association with human milk output
  • New data on body composition of young children..
  • PhD thesess
  • Publications in the form of scientific reports and peer-reviewed papers.

Expected Research Outcomes
  • To contribute to improved understanding of infant feeding practices and body composition during the first 2 years of life.
  • To contribute to capacity building in nutrition by training of PhD students
Proposal submission forms

Research institutions in Member States interested in participating in this CRP are invited to submit proposals directly to the Research Contracts Administration Section (NACA) of the International Atomic Energy Agency: Official.Mail@iaea.org or to Ms Lena Davidsson: L.Davidsson@iaea.org The forms can be downloaded from http://www-crp.iaea.org/html/forms.html. For more information about research contracts and research agreements, please visit our web-site: http://www-crp.iaea.org/html/faqs.html.

Deadline for submission of proposals

Proposals must be received no later than than 1 August 2011.
Transmission via Email is acceptable if all required signatures are scanned.

For additional information, please contact:
Lena Davidsson
Section Head
Nutritional and Health-Related Environmental Studies Section
Division of Human Health
International Atomic Energy Agency (IAEA)
Wagramer Strasse 5
A-1400 Vienna, Austria
Phone: +43-1-2600-21635 or 21674
Fax: +43-1-2600-7
L.Davidsson@iaea.org 


References
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  2. CABALLERO, B., A nutrition paradox – underweight and obesity in developing countries, N. Engl. J. Med. 352 (2005) 1514–6.
  3. LOPEZ, A.D., et al., Global and regional burden of disease and risk factors, systematic analysis of population health data, The Lancet 367 (2006) 1747-57.
  4. HORTON, R., Maternal and child undernutrition: an urgent opportunity, Lancet 371 (2008) 179.
  5. WORLD BANK, Repositioning nutrition as central to development, The International Bank for Reconstruction and Development, The World Bank, Washington DC (2006) http://siteresources.worldbank.org/NUTRITION/Resources/281846-1131636806329/NutritionStrategy.pdf.
  6. The Lancet Series on Maternal and Child Undernutrition, Executive Summary, The Lancet (2008) http://www-tc.iaea.org/tcweb/abouttc/tcseminar/Sem6-ExeSum.pdf.
  7. FARUQUE, A.S., et al., Nutrition: basis for healthy children and mothers in Bangladesh, J. Popul. Nutr. 26 3 (2008) 325-39.
  8. BHANDARI, N., et al., Mainstreaming nutrition into maternal and child health programmes: scaling up of exclusive breastfeeding, Matern. Child Nutr.4(Suppl 1) (2008) 5-23.
  9. SEKELUND, U., et al., Association of weight gain in infancy and early childhood with metabolic risk in young adults, J. Clin. Endocrinol. Metab. 92 (2007) 98-103.
  10. GILLMAN, M.W., The first months of life: a critical period for development of obesity, Am. J. Clin. Nutr. 87 (2008) 1587-1589.
  11. INTERNATIONAL ATOMIC ENERGY AGENCY, Stable isotope technique to assess intake of human milk in breastfed infants, IAEA Human Health Series No. 7., IAEA Vienna (2010) http://www-pub.iaea.org/MTCD/publications/PDF/Pub1429_web.pdf.
  12. BARKER, D.J., The developmental origins of adult disease, J Am Coll Nutr. 3 (Suppl 6) (2004) 588S–95S.
  13. WORLD HEALTH ORGANIZATION, Child growth standards: Methods and development: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age, WHO, Geneva (2007) http://www.who.int/childgrowth/publications/technical_report_pub/en/index.html
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  18. KAIN, J., et al., Accelerated growth in early life and obesity in preschool Chilean children, Obesity (Silver Spring) 17 8 (2009) 1603-1608.
  19. IANNOTTI, L.L., et al., Growth and body composition of Peruvian infants in a periurban setting, Food Nutr Bull. 30 3 (2009) 245-53.
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  23. INTERNATIONAL ATOMIC ENERGY AGENCY, Introduction to body composition assessment using the deuterium dilution technique with analysis of saliva samples by Fourier Transform Infrared Spectrometry (FTIR), IAEA Human Health Series No. 12, IAEA Vienna (2010) http://www-pub.iaea.org/MTCD/publications/PubDetails.asp?pubId=8369.
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  26. IWORLD HEALTH ORGANIZATION, Guidelines on HIV and infant feeding, WHO, Geneva (2010) http://whqlibdoc.who.int/publications/2010/9789241599535_eng.pdf.