Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
STRUCTURE FOR CONSIDERING MICRONUTRIENTS (VAD, IDD, IDA) SITUATION what is the micronutrient and deficiency? causes and consequences of deficiency assessment methods prevalences, trends, who is affected... goals, monitoring of progress. PREVENTION METHODS FOR DEFICIENCES supplementation fortification dietary change program planning and implementation supporting policies and contextual factors costs, effects, budget, finance. RECENT PROGRESS AND OUTLOOK trends in programs trends in outcome current and new policies and programs and unmet needs emerging problems. MICRONUTRIENTS VITAMINS (essential organic compounds not synthesized in the body) Fat soluble: A, E, K; essential fatty acids; 'vitamin D' function in membranes, antioxidants, hormones, transmitters. Water soluble: B complex, C cofactors in metabolic pathways; maybe many others for C. ESSENTIAL MINERALS (cannot be synthesized; electrolytes like sea water) Macro (usually milligram daily needs): Ca, P, Na, K, Fe, Mg, Zn electrolyte balance; bone structure; active site -- haemoglobin, enzymes. Micro (v small amounts essential) iodine: hormone constituent. USEFUL SUBSTANCES DRAWN FROM DIET Many plant constituents still to be characterized: antioxidants, anti-cancer, probably other benefits. Methods for assessing deficiencies of VA, iron, and iodine. Deficiency Diet Biological outcome Function Vitamin A VA-rich food frequencies, intakes (also fat) Serum retinol Night blindness Eye damage (Bitot’s spots) Survival Iron Haem iron intake Inhibitors Vitamin C Haemoglobin (Hb) (Anaemia) Physical work. Pregnancy/maternal health. Cognitive development and behaviour Iodine Iodized salt Goitre TSH IQ. Schooling. Physical and mental vigour Table 1. Indicators of micronutrient deficiencies as established by WHO Vitamin A Iodine Iron Clinical Xerophthalmia Night blindness (XN) in children 24-71 months of age Bitot’s spots (X1B) Sum (XN+X1B) used here Goitre Grade 1=palpable not visible Grade 2=visible when neck in normal position Sum (grades 1+2) used here. Anemia Hb <12g/dl in non-pregnant women >15 yrs of age Hb <11g/dl in pregnant women of any age Hb <13g/dl in men >15 yrs* Hb <11g/dl in children 6-60 months Hb <11.5g/dl in children 5-11 yrs* Hb <12g/dl in children 12-14 yrs* Subclinical Retinol level In serum, <0.7 mcmol/l (=20mcg/dl) In breast milk, <1.05mcmol/l Urinary iodine* Median (for population) <100 mcg/l Serum ferritin* TSH (neonates)* Level > mU/l WHO – World Health Organization. Hb = haemoglobin. TSH – thyroid stimulating hormone. Sources: Howson et al (1998a, table 2.1); for vitamin A, WHO (1996); for iodine, WHO (1994); for iron, WHO/UNICEF/UNU (1997). * Indicator not used in this report. Table copied from Mason et al, 2001, p.4 (The Micronutrient Report) DIET VA: Iron: Iodine: frequency of VA-rich foods by recall (e.g. 24 hr) – see Sommer 1995, Nepal. Best to internally compare. haem iron (red meats); semi-quantitative at best; bioavailability very variable and low (e.g. 5-15%); inhibitors tannins (tea) and phytates (cereals). iodized salt if endemic area (otherwise seafood). BIOLOGICAL OUTCOME Blood: VA: sample or dried blood spot for serum retinol by HPLC or (?) fluorimetry; RDR or MRDR, children. Hb: droplet of blood by HemoCue or similar method; women and children. TSH: blood spot immunoassay (expensive) on neonates. Urine: Chemical analysis of iodine in urine casual sample: school age children. Examination: Goitre, all ages. Night blindness and/or Bitot’s spots (XN/X1B): children and women. Underweight Anemia VAD IDD L E As i M Ea st SS a/ /N Am Pa S Af A As c fr i /C r ic i f c ar ia ic a a Figure 13. Summary of estimated regional prevalences of underweight, anemia, vitamin A deficiency (sub-clinical), and IDDs, in pre-school children, c.1995 (see table 8 for data) 0 20 40 60 TABLE 23. Estimated reductions in the disease burden (% DALYs lost) in developing countries (all population groups, all causes), from children underweight or deficiencies of vitamin A (clinical), iodine (measured as goiter), and anemia; from the direct effect (the deficiency considered as a disease itself) and as a risk factor for other diseases (infectious diseases only included in estimating reduction). Child underweight Vitamin A deficiency Anemia IDDs Total Direct effect 1.0% 1.0% 3.3% 4.7% 10.0% As risk factor 14.0% 4.5% 0.3% 3.7% 22.5% Total 15.0% 5.5% 3.6% 8.4% 32.5% Note: underweight refers to children 0-59 months, < - 2 SDs weight-for-age; vitamin A deficiency is calculated from clinical deficiency in children 0-59 months; anemia refers to women 15-49 years; IDDs refers to iodine deficiency disorders, all ages, calculated from goiter prevalences. Methods are given in the source. Source: Mason, Musgrove & Habicht, (2003), table 10: [39] CONTROLLING MICRONUTRIENT DEFICIENCIES OPTIONS - FORTIFICATION - SUPPLEMENTATION - DIETARY CHANGE Strategy now … Diet Fortification Supplementation Other IDD Reduce goitrogens Salt Oral iodized oil in extreme cases Sterilize using I (milk, maybe water) VAD Orange yellow fruits and vegetables. Red palm oil Animal foods Breast milk Sugar Vegetable oil Many commercial products Frequent low dose VA Phase out periodic VACs, except post delivery Deworm Increase fat Iron deficiency Vitamin C Haem iron Avoid tannins, phytates Flour Try for rice Soy and fish sauces Fe/folate or MMNs, daily/weekly Especially during pregnancy Drink tea not during meal Delay cord cutting Ferric iron not much use. (nor is ‘enrichment’) Sequence of intervention development Large scale programs Effectiveness m&e, to build improvement and sustainability VAC distribution iodized salt Trial/pilot -- Efficacy and acceptability research VA fortification (esp. oil, otherwise with multi) multi fortification of commercial foods multi ‘sprinkles’ multi supplementation esp. in pregnancy Research and Development iron fortification of staples, esp. rice iron in salt