ORIGINS OF CONTEMPORARY INTEREST Sommer and Vitamin A (1983; 1986) Hidden Hunger/Micronutrient Malnutrition (1994)
FRAMEWORK/DEFINITIONS Micronutrients: Vitamins and elements (minerals) essential or beneficial to human nutrition Hidden Hunger: Synonymous with micronutrient undernutrition. The constellation of deficiencies of vitamins and minerals
FRAMEWORK/DEFINITIONS Iron Deficiency: A lower than adequate total-body content of iron resulting in limitation of iron for the physiological and anatomical functions of the nutrient Anemia: A state of insufficient circulating red blood cells to meet the needs of optimal oxygen transport to the peripheral tissues of the body. Commonly assessed in relation to reference values of hemoglobin concentration Iron Deficiency Anemia: Anemia as the end-stage outcome of iron deficiency leading to underproduction of red blood cells
GEOGRAPHIC EXTENSION/HOT SPOTS/RELEVANCE Vitamin A deficiency map WHO: http://www.who.int/vmnis/en/
Physiological Aspects of iron deficiency: Interaction of nutrition and infection: Nutritional immunity Intracellular pathogens favored by available iron Ameba Plasmodium Mycobacterium ? HIV retrovirus
ISSUES IN IRON DEFICIENCY MITIGATION Public Health Supplementation Policy The WHO considers any population segment with >40% anemia prevalence to have a severe anemia problem and to merit intervention. Universal supplementation: Stoltzfus and Dreyfuss (1998) recommend a daily regimen of 12.5 mg iron and 50 g of folic acid across the population from 6 to 24 months of age.
ISSUES IN IRON DEFICIENCY MITIGATION Malaria and Non-transferrin-bound Iron Sazawal S et al. Effects of routine prophylactic supplementation with iron and folic acid on admission to hospital and mortality in preschool children in a high malaria transmission setting: community-based, randomized, placebo-controlled trial. Lancet 2006:367:133-143. Outcome: The trial was halted prematurely when excess adverse effects in the iron-treatment groups (Fe, Fe + Zn) were detected. There was excess hospitalization + mortality with exposure to iron supplementation. Mechanism: The potential mechanism for adverse effects is the circulation of non-transferrin-bound iron (NTBI) or “free iron” rising in the blood after the oral 12.5 mg of iron.
ISSUES IN IRON DEFICIENCY MITIGATION Daily versus Weekly Supplementation The notion of weekly supplementation to reduce cumulative iron exposure, program cost, and improve compliance with iron supplementation interventions has been advanced since the 1990s. The International Research on Infant Supplementation (IRIS) trial (Vietnam, Indonesia, Peru,South Africa) found weekly iron dosing to be intermediary in its effects between no-treatment and daily supplementation …. slow but steady. Guatemala has a mandated program of 65 mg of iron weekly as ferrous sulfate for children 6 to 71 mo of age.
ISSUES IN IRON DEFICIENCY MITIGATION Alternatives for Iron Fortification Flour Fortification Standards Home-fortification of Complementary Foods Biofortification with Iron in Plants
Update on Vitamin A: Vitamin A supplementation in early life in HIV improved growth and survival A genetic polymorphism for more and less efficient intestinal bioconversion of beta-carotene to vitamin A by carotene monooxidase 1 (CMO1) Recent publication title: Indonesian women of childbearing age are at greater risk of clinical vitamin A deficiency in families that spend more on rice and less on fruits/vegetables and animal-based foods.
Update on Iodine: Salt iodization coverage rose from 20% to 80% worldwide through efforts of UNICEF and other international agencies through the 1990s. The profound myxedematous goiter observed in central Africa may be a combination of prevailing iodine deficiency with a background of selenium deficiency. Vitamin A status modulates thyroid gland metabolism, peripheral metabolism of thyroid hormone, and production of thyrotropin (TSH) by the pituitary.
Update on Zinc: A published Cochrane meta-analysis confirms the efficacy of adjunctive oral zinc supplementation in mitigating acute diarrhea. It has an emetic effect. A published meta-analysis suggests that more recent field intervention studies with zinc supplementation fail to confirm a positive linear growth response. A systematic review of the literature finds that oral zinc supplementation reduces the incidence of diarrhea by 27% and of LRI by 15%. Positive effects from fortification programs with zinc have yet to be confirmed.
Update on Dietary Folates and Folic Acid: Origins of the recommendation for 400 μg/day for in children is a direct extension from the intake level needed to protect fertile women from NTD-complicated pregnancy. Folates are reduced, polyglutamates of the basic compound; folic acid is a totally oxidized monoglutamate, which only occurs as the synthetic supplement and fortificant form. Circulating levels of “free” folic acid occur after consumption of the folic acid in a bowl of fortified breakfast cereal. Carcinogenesis for adult tumors (colon, prostate) may have increased following the mandating of higher standards of folic acid fortification.
Update on Vitamin D: Rickets is occurring in tropical countries in which infants are fully wrapped, mothers are fully wrapped and neither is getting vitamin D supplements. Rickets increased in breast-feeding offspring of dark- skinned mothers in temperate countries with no infant vitamin D supplements. American Academy of Pediatrics doubled childhood recommended intake from 200 (RDA) to 400 IU (AAP). Vitamin D protects at sites other than non-osseous tissues from degenerative diseases.
TAKE-HOME MESSAGES: DEFICIENCIES Not all anemia is iron deficiency anemia. Programs to alleviate iron deficiency and IDA in at-large populations have limited effectiveness. Exposure of those without ID to excessive iron can have adverse consequences. Weekly iron supplementation may improve both its effectiveness and safety.
TAKE-HOME MESSAGES: DEFICIENCIES The vitamin A issue is targeting the most responsive segments. The iodine issue is to maintain and extend gains in salt fortification. The zinc issue is moving from supplementation to fortification. The folic acid issue is short and long-term safety. The vitamin D issue is defining and achieving appropriate intakes.
SUGGESTED READING Iron Literature McLean E, Cogswell M, Egli I, Wojdyla D, de Benoist B. Worldwide prevalence of anaemia, WHO Vitamin and Mineral Nutrition Information System, 1993-2005. Public Health Nutr 2009;12:444-454. Schűmann K, Christ F. Did the “iron age” end in Pemba. Sight and Life Magazine 2007 available at http://www.sightandlife.org/pdf/magazine_0307.pdf Beard J. Iron, Chpt 34, in Bowman BA, Russell RM (eds). Present Knowledge in Nutrition, 9 th Edition Washington: ILSI Press, 2006:430-444.
SUGGESTED READING (con’t) Other Micronutrients Literature Brown KH, Hess SY (eds). Supplement. International Zinc Nutrition Consultative Group Technical Document #2. Systematic Reviews of Zinc Intervention Strategies. Food Nutr Bull (Suppl 1):S3-S184. United Call to Action. Nutrition interventions an investment for the future. Available at http://www.unitedcalltoaction.org/ http://www.unitedcalltoaction.org/