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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

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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