F&N Bulletin Vol 23 No 1b - United Nations University

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10 V. Iyengar » Stable isotopic techniques are used routinely to assess the absorption of iron, copper, zinc, selenium, calcium, and magnesium from test meals. It is possible to extend the range of application to other elements, such as molybdenum, nickel, vanadium, tin, and boron, to better understand their biological functions. Semistable, very long-lived radionuclides (aluminum-26, manganese-53, and iodine-129) can be used for monoisotopic elements. » Use of stable isotopic techniques for absorption studies is not limited to those elements that are essential to the human body. They can also be used for toxicological studies of lead, cadmium, mercury, and chromium. For heavy metals, stable isotopic techniques have been used in humans to study cadmium absorption. » Impressive progress has been seen in the instrumentation of isotope ratio mass spectrometry (IRMS) incorporating a gas-chromatographic interface. This improvement facilitates the conversion of specific compounds to carbon dioxide, hydrogen, or nitrogen, yielding compounds specific to isotope ratio measurements. This is expected to open new and exciting applications in nutritional sciences. Conclusions Isotopic techniques have been used extensively in industrialized countries to analyze human energy requirements, human body composition, and the metabolism of important nutrients, such as protein, fat, vitamins, and minerals. The information acquired has led directly to many improvements in nutrition and health. These techniques have only begun to be applied in developing countries, where they can not only benefit millions through improved nutrition, but also serve as specific indicators of broader social and economic advances. Stable isotopes provide the only direct way to measure iron uptake and bioavailability and are regarded the “gold standard” for iron studies in humans. Isotopic methods are unique for measuring the absorption of zinc from foods and breastmilk intake by infants. References 1. WHO. Nutrition for health and development (NHD). Progress and prospects on the eve of the 21st century. Geneva: World Health Organization, 1999. 2. UNICEF. The state of the world’s children 1998. Oxford: Oxford University Press, 1997. 3. WHO. Global database on child growth and malnutrition: forecast of trends. Document WHO/NHD/99.12. Geneva: WHO, 1999. 4. UNICEF. Malnutrition in South Asia. A Regional profile, ROSA Publication. Kathmandu, Nepal: UNICEF Regional Office for South Asia, 1997. 5. James WPT. The nutritional crisis to come. In: Koop EC, Pearson C, Schwarz RM, eds. Critical issues in global health. San Francisco, Calif, USA: Jossey-Bass, 2001:238–50. 6. World Bank. World development indicators. World development report 1994: infrastructure for development. Washington, DC: World Bank, 1994. 7. Underwood B. Undernutrition. In: Koop EC, Pearson C, Schwarz RM, eds. Critical issues in global health. San Francisco, Calif, USA: Jossey-Bass, 2001:229–37. 8. WHO. Global database on body mass index (BMI). Geneva: World Health Organization, 1999. 9. Iyengar GV, Nair PP. Global outlook on nutrition and the environment: meeting the challenges of the next millennium. The Science of the Total Environment 2000; 249:331–46. 10. Prasad AS. Essential and toxic trace elements in health and disease. New York: Alan R. Liss, 1988. 11. Goyer RA. Toxic and essential metal interactions. Annu Rev Nutr 1997;17:37–50 12. Goyer RA. Transplacental transport of lead. Environ Health Perspect 1990;89:101–5. 13. Elsenhans B, Schuemann K, Forth W. Toxic metals: interactions with essential metals. In: Rowland IR, ed. Nutrition toxicology and cancer. Boca Raton, Fla., USA: CRC Press, 1991:223–58. 14. Iyengar GV. Elemental analysis of biological systems. Boca Raton, Fla., USA: CRC Press, 1989. 15. IAEA. Harmonization of health related environmental measurements using nuclear and isotopic techniques. Vienna: International Atomic Energy Agency, 1997. 16. Mellon FA, Sandstroem B, eds. Stable isotopes in human nutrition. Inorganic nutrient metabolism. New York: Academic Press, 1996. 17. Klein PD, Klein ER. Stable isotope usage in developing countries: safe tracer tools to measure human nutritional status. International Atomic Energy Agency Bulletin 1987;4:41–4. 18. IAEA. Targeting malnutrition. Isotopic tools for evaluating nutrition worldwide. Vienna: International Atomic Energy Agency, 1996. 19. Anand S, Ravallion M. Human development in poor countries: on the role of private incomes and public services. J Econ Perspect 1993;7:133–50. 20. Nutrition and Health Related Environmental Studies— NAHRES-57. Report of the advisory group meeting to review the IAEA’s current nutrition activities and to identify relevant new areas. Vienna: International Atomic Energy Agency, 2000.
Palm oil: A healthful and cost-effective dietary component A. S. H. Ong and S. H. Goh Abstract Palm oil is an excellent choice for food manufacturers because of its nutritional benefits and versatility. The oil is highly structured to contain predominantly oleic acid at the sn2-position in the major triacylglycerols to account for the beneficial effects described in numerous nutritional studies. Oil quality and nutritional benefits have been assured for the variety of foods that can be manufactured from the oil directly or from blends with other oils while remaining trans-free. The oxidative stability coupled with the cost-effectiveness is unparalleled among cholesterol-free oils, and these values can be extended to blends of polyunsaturated oils to provide long shelf-life. Presently the supply of genetic-modificationfree palm oil is assured at economic prices, since the oil palm is a perennial crop with unparalleled productivity. Numerous studies have confirmed the nutritional value of palm oil as a result of the high monounsaturation at the crucial 2-position of the oil’s triacylglycerols, making the oil as healthful as olive oil. It is now recognized that the contribution of dietary fats to blood lipids and cholesterol modulation is a consequence of the digestion, absorption, and metabolism of the fats. Lipolytic hydrolysis of palm oil glycerides containing predominantly oleic acid at the 2 position and palmitic and stearic acids at the 1 and 3 positions allows for the ready absorption of the 2-monoacylglycerols while the saturated free fatty acids remain poorly absorbed. Dietary palm oil in balanced diets generally reduce blood cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides while raising the high-density lipoprotein (HDL) cholesterol. Improved lipoprotein(a) and apo-A1 levels were also demonstrated from palm oil diets; an important benefit also comes from the lowering of blood triglycerides (or reduced fat storage) as A. S. H. Ong is affiliated with the Institute of Advanced Studies at the University of Malaya in Kuala Lumpur, Malaysia. S. H. Goh is affiliated with the Forest Research Institute of Malaysia, Kepong, in Kuala Lumpur. compared with those from polyunsaturated fat diets. Virgin palm oil also provides carotenes apart from tocotrienols and tocopherols that have been shown to be powerful antioxidants and potential mediators of cellular functions. These compounds can be antithrombotic, cause an increase of the prostacyclin/thromboxane ratio, reduce restenosis, and inhibit HMG-CoA-reductase (thus reducing) cholesterol biosynthesis). Red palm oil is a rich source of β-carotene as well as of α-tocopherol and tocotrienols. Introduction Oils and fats are macronutrients for humans, who need to consume about 20 to 25 kg per capita per year, as recommended by the World Health Organization (WHO). People in some countries consume excessive amounts of oils and fats—about 40 to 50 kg per capita—with adverse effects on health; in contrast, a number of the most populous countries in the world consume only about 8 to 9 kg per capita per year, which is inadequate. For good health, one needs a balanced diet, including oils and fats that supply energy and essential fatty acids. There are many sources of oils and fats, but soybean oil, palm oil, sunflower seed oil, and rapeseed oil contribute 60% to 70% of the world’s production. All oils and fats have the triacylglycerol or triglyceride structures shown below. Their differences lie in the types of fatty acids (RCOOH) attached to the glycerol backbone in positions 1, 2, and 3. R 2 COO 1 CH 2 -OOCR 1 2 C H 3CH 2 -OOCR 3 Triacylglycerol (TAG) or Triglyceride HO 1 CH 2 -OOCR 1 C H 3CH 2 -OOCR 3 1,3-Diacylglycerol (DAG) R 2 COO CH 2 -OH 2 C H CH 2 -OH 2-Monoacylglycerol (MAG) Fats and oils are classified simply as saturated, monounsaturated, and polyunsaturated depending on Food and Nutrition Bulletin, vol. 23, no. 1 © 2002, The United Nations University. 11
Page 1 and 2: Contents Review articles Nuclear an
Page 3 and 4: Special Article Nuclear and isotopi
Page 5 and 6: Nuclear and isotopic techniques 5 T
Page 7 and 8: Nuclear and isotopic techniques 7 T
Page 9: Nuclear and isotopic techniques the
Page 13 and 14: Palm oil will be less absorbed and
Page 15 and 16: Palm oil oil at the present time is
Page 17 and 18: Palm oil crystal forms for the requ
Page 19 and 20: Palm oil myristic acid (14:0) is hi
Page 21 and 22: Palm oil 13. Kritchevsky D. Influen
Page 23 and 24: Introduction to three regional stud
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Iron and energy supplementation The
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Iron and energy supplementation 63
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News and notes 2001 World Food Priz
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