Transcript i613-mns-intro

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