targeted levels of minerals in plant foods ... · case of iron biofortification in cereals baseline...
TRANSCRIPT
HarvestPlus c/o IFPRI 2033 K Street, NW • Washington, DC 20006-1002 USA Tel: 202-862-5600 • Fax: 202-467-4439 [email protected] • www.HarvestPlus.org
Targeted Levels of Minerals in Plant Foods: biofortification & post harvest fortification
Erick Boy
Workshop: “Improving the composition of plant foods for better mineral nutrition”
June 4, 2012
ETH Zurich, Zurich, Switzerland
Basic Definitions
• Biofortification: enhancement of iron or zinc in edible portion of a staple food crop through traditional plant breeding without sacrificing agronomic qualities (i.e. yield). No additional cost to consumer.
• Fortification: addition of lost or missing minerals to a massively consumed or targeted food/condiment vehicle that is consumed regularly in predictable amounts, without affecting the vehicle’s organoleptic characteristics.
Considerations
• Legal: vary by country (GMOs, enforcement)
• Technical: biomarkers, requirements, UL, alteration of organoleptics
• Biological – Plants (natural mineral density range)
– Humans (bioavailability)
• Economic
• Cultural: consumer acceptance
Context of Targets: PH Fortification Program Implementation Steps
• Defining the target population
• Assessing mineral intake and status
• Selecting the food vehicle(s)
• Selecting the mineral fortificant
• Determining the level of mineral fortificant*
• Establishing the regulatory parameters
• Costs: initial investment & recurring
• Monitoring and evaluation*
• Communicating and marketing fortification programmes*
Establishing the nutrient target level
• The EAR cut-point method and the probability method give similar results as long as the assumptions underlying them are met.
• The dietary goal of fortification formally defined: …to provide most (97.5%) of individuals in the population group(s) at greatest risk of deficiency with an adequate intake of specific micronutrients, without causing a risk of excessive intakes in this or other groups. WHO (2006)
• most individuals of the population satisfy 80% of RNI
What usually happens is….
• PH Food fortification programs are devised so as to achieve a level of fortification such that, when the program is in place, the probability of the nutrient intake being inadequate in a given population – either insufficient or excessive – is acceptably low.
However…
• Micronutrient fortification is not universally applicable. – High degree of decentralization of food processing
activities.
– Subsistence farming is predominant
Source: FAO. 1996. Food fortification: Technology and quality control
INTERVENTIONS OVERLAP
BIOFORTIFICATION (RURAL POOR)
TARGETED FORTIFICATION
(LIFE CYCLE STAGES)
MASS FORTIFICATION (URBAN POOR)
Supplementation
Challenges in Developing & Evaluating biofortified foods as a viable public health intervention
Estimate target micronutrient
content
Development
Nutrient Retention
Challenges: Minimizing losses of mineral during processing
Consumption Level
Challenges: Avail. of representative dietary intake data.
Bioavailability
Challenges: Overcoming low bio-avail. of iron. Quantifying +/- effects from whole diets.
Evaluation
Efficacy Challenges: Determine effect of infections on efficacy. Identify adequate and sensitive biomarkers of micronutrient status.
Effectiveness
Challenges: Breeding agronomic traits into biofortified staple. Functional seed extension systems . Farmer acceptance if sensory characteristics are altered Creating demand. Hotz & McClafferty, 2007, FNB, 28 (2), S271-79
Genetic Variation, Baseline & Target Levels
Wolfgang H PFEIFFER
45 Target Increment
15 15
30
8 30 8
What IF we do not have the levels? Case of Iron Biofortification in Cereals █ Baseline █ Could be Achieved by breeding by 2013 ▼ Target
P l Mill tRice
WheatMaize
Wo
lfgan
g H
PF
EIF
FE
R
Germplasm still below the 100 % target levels by 2013 for the three main cereals even if breeding would concentrate on
increasing iron levels
Transgenic approach is only option
0 20 40 60 80 100 120 140
Iron µgg-1
HarvestPlus c/o IFPRI 2033 K Street, NW • Washington, DC 20006-1002 USA Tel: 202-862-5600 • Fax: 202-467-4439 [email protected] • www.HarvestPlus.org
Biofortification Timeline: Wheat Southeast Asia
Preliminary Biofortification Iron Target and Research Findings for Common Beans and Pearl Millet Additional Iron provides 30% EAR
Original Beans and Pearl Millet Iron Breeding Targets for Non Pregnant Non lactating women
Nutrient FOOD Consumed (g/day)
X "+Nutrient Concentration (mcg/g)"
X Nutrient Retained (%)
X Absorbed proportion (%)
= Nutrient absorbed (μg/day)
EAR NP NL Woman (mcg)
Iron Beans
200 x 44.0 x 90 x 5.0 = 396 1460
Iron Pearl Millet
300 x 30.0 x 90 x 5.0 = 406
Iron absorbed = % EAR
= 27% Beans
Iron Required = 28% Pearl
Millet
Updated Fe Breeding Targets for Beans & Pearl Millet Non Pregnant Non lactating women
Nutrient FOOD Consumed (g/day)
X "+Nutrient Concentration (mcg/g)"
X Nutrient Retained (%)
X Absorbed proportion (%)
= Nutrient absorbed (μg/day)
EAR NP NL Woman (mcg)
Iron Beans
185 x 44.0 x 95 x 5.0 = 313 1460
Iron Pearl Millet
167 x 30.0 x 95 x 7.0 = 333
Iron absorbed = % EAR
=
21% Beans Rwanda
Iron Required = 23% Pearl
Millet Maharashtra
How much additional iron is needed to have a biological impact?…at least an additional intake equivalent to 60% EAR of iron was required to improve iron stores, and at least 90% EAR was needed to decrease nutritional anemia. [fish sauce, salt, refined wheat flour, & wheat flour biscuits).
Preliminary Biofortification Target and Research Findings for Zinc-biofortified rice Additional Zn provides 40% EAR
Rice Intake in rural Bangladesh: as high as assumed
Distributions of usual rice intakes of primary female caregivers and children (rice, raw, g/d)
Both districts Mean Median
(25th, 75th) P-value1
WOMEN (n=478) 422 420 (365, 476)
0.0022
CHILDREN 2-4 yr (n=463)
138* 134 (99, 172)
0.08
No Seasonal effect (p>0.05) *30% EAR
Current and simulated prevalence of inadequate zinc intakes – rural Bangladesh (+8 ppm Zn from 12 to 20 ppm)
Source: Arsenault J et al AJCN 2009. Adequacy level is EAR of 2 mg zinc for 1-3 y old children (IZiNCG)
0
5
10
15
20
25
30
Current 35% 70%
%
TrishalPirgacha
Data from Arsenault et al, J Nutr, 2010
Original Zn targets for rice and whole wheat for Non Pregnant Non lactating women
Nutrient FOOD Consumed (g/day)
X "+Nutrient Concentration (mcg/g)"
X Nutrient Retained (%)
X Absorbed proportion (%)
= Nutrient absorbed (μg/day)
EAR NP NL Woman (mcg)
Polished Rice
400 x 8.0 x 90 x 25.0 = 720 1860
W. Wheat
400 x 8.0 x 90 x 25.0 = 720
Total Zn absorbed = % EAR
=
38% P. polished Rice
EAR = 38% Whole
Wheat
Revised Zn targets for rice and whole wheat for Non Pregnant Non lactating women
Nutrient FOOD Consumed (g/day)
X "+Nutrient Concentration (mcg/g)"
X Nutrient Retained (%)
X Absorbed proportion (%)
= Nutrient absorbed (μg/day)
EAR NP NL Woman (mcg)
Polished Rice
422 x 8.0 x 90 x 20.0 = 607 1860
W. Wheat
400 x 8.0 x 95 x 15.0 = 456
total Zn absorbed = % EAR
=
33% P. polished Rice
EAR = 24% Whole
Wheat
Summary
BIOFORTIFICATION FORTIFICATION
TARGET POPULATION RURAL POOR / HOUSEHOLDS
(WCBA & C4-6 y)
TARGETABLE TO LIFE CYCLE STAGE & SPECIFIC
CONTEXTS
DIETARY/NUTRITIONAL GOAL (% EAR)
LIMITED BY GERMPLASM
VARIABILITY (30-40% EAR)
LIMITED BY FOOD:FORTIFICANT
INTERACTIONS (100% EAR)
PREFERRED VEHICLES STAPLE FOODS PROCESSED STAPLES +
DEVELOPMENT ~10 YRS <10 YRS
SUSTAINABILITY (RECURRING COSTS – FORTIF. PROCESS, DISTRIB. SYSTEM, M%E)
HIGH (ONE TIME INVESTMENT IN
DEVELOPMENT OF EACH VARIETY)
MODERATE (VARIES BY COST OF FORTIFICANT, FORTIF. PROCESS AND
M&E)
Summary
BIOFORTIFICATION FORTIFICATION
POTENTIAL NUTRITIONAL IMPACT
POPULATION INTAKE/STATUS RIGHT-
SHIFT
POPULATION (M) INDIVIDUAL (T) STATUS IMPROVEMENT; HIGHER
CEILING
POTENTIAL FOR TOXICITY LOW-NONE LOW
RESEARCH NEEDS EFFICACY & EFFECTIVENESS TRIALS
EFFECTIVENESS > EFFICACY TRIALS (VARIES BY MINERAL)
NUTRIENT RETENTION POST HARVEST POST PROCESSING
BIOAVAILABILITY (MARGINALLY FE-DEFICIENT SUBJECTS…LOW ZN DIETS)
FE: 3-7% MEALS ZN: 5-15% PORRIDGE
& FLAT BREAD
MORE MODIFIABLE (FE SALTS, enhancers, phytase) SIMILAR to BIOFORTIFIED FOODS
Points of discussion 1. Bioavailability in mixed diets: range of values
2. Upper Level of Intake: revise Zn up?
3. Dietary vs nutritional goals (%EAR from fortification that will produce significant nutritional effect(s))
4. When is it important to estimate the impact of overlapping interventions in a given population? Determine boundaries a priori?
5. Dietary and/or nutritional outcome associated with target level?
Thank you