View Full Table | Close Full ViewTable 1.

The known essential nutrients for human life

 
Air, water, and energy Protein (amino acids) Lipids–Fat (fatty acids) Macrominerals Essential trace elements Vitamins
Oxygen Histidine Linoleic acid Na Fe A (retinol)
Water Isoleucine Linolenic acid K Zn D (calciferol)
Carbohydrates Leucine Ca Cu E (α-tocopherol)
Lysine Mg Mn K (phylloquinone)
Methionine S I C (ascorbic acid)
Phenylalanine P F B1 (thiamin)
Threonine Cl Se B2 (riboflavin)
Tryptophan Mo B3 (niacin)
Valine Co (in B12) B5 (pantothenic acid)
B B6 (pyroxidine)
B7 (biotin)
B9 (folic acid, folacin)
B12 (cobalamin)
Numerous other beneficial substances in foods are also known to contribute to good health.



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Information and assumptions used to set target levels for micronutrient content of biofortified staple food crops.

 
Amount eaten or nutrient Criteria Rice (polished) Wheat (whole) Pearl millet (whole) Beans (whole) Maize (whole) Cassava (fresh wt.) Sweet potato (fresh wt.)
Per capita consumption Adult women (g/d) 400 400 300 200 400 400 200
Children 4–6 yr (g/d) 200 200 150 100 200 200 100
Fe % of EAR to achieve ∼30
EAR, nonpregnant, nonlactating women (μg/day) 1460
EAR, children 4–6 yr (μg/d) 500
Micronutrient retention after processing (%) 90 90 90 85 90 90 90
Bioavailability (%) 10 5 5 5 5 10 10
Baseline micronutrient content (μg/g) 2 30 47 50 30 4 6
Additional content required (μg/g) 11 22 30 44 22 11 22
Final target content (μg/g) 13 52 77 94 52 15 28
Final target content as dry wt. (μg/g) 15 59 88 107 60 45 85
Zn % of EAR to achieve ∼40
EAR, nonpregnant, nonlactating women (μg/d) 1860
EAR, children 4–6 yr of age (μg/d) 830
Micronutrient retention after processing (%) 90 90 90 90 90 90 90
Bioavailability (%) 25 25 25 25 25 25 25
Baseline micronutrient content (μg/g) 16 25 47 32 25 4 6
Additional content required (μg/g) 8 8 11 17 8 8 17
Final target content (μg/g) 24 33 58 49 33 12 23
Final target content as dry wt. (μg/g) 28 38 66 56 38 34 70
Provitamin A % of EAR to achieve ∼50
EAR, nonpregnant, nonlactating women (μg/d) 500
EAR, children 4–6 yr of age (μg/d) 275
Micronutrient retention after processing 50 50 50 50 50 50 50
Bioavailability ratio (μg:RE ) 12:1 12:1 12:1 12:1 12:1 12:1 12:1
Baseline micronutrient content (μg/g) 0 0 0 0 0 1 2
Additional content required (μg/g) 15 15 20 30 15 15 30
Final target content (μg/g) 15 15 20 30 15 16 32
Final target content as dry wt. (μg/g) 17 17 23 34 17 48 91
EAR, estimated average requirement.
RE, retinyl esters.



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Breeding progress as of 2007–2008 (iron, zinc, provitamin A expressed as percent of breeding target in lines at indicated stage of breeding).

 
Screening Crop improvement G × E testing Launch
Crop Screening gene/trait identification validation Early development parent building Intermediate product development Final product development Performance G × E testing in target countries Release prelaunch seed multiplication
Sweet potato NARS Uganda Program Introduction NARS Uganda
 Breeding Provitamin A 100% target 100% 100% 100% 100%
 Fast-track Uganda, Mozambique 100% 100%
Maize
 Breeding Provitamin A 100% target 60% 50% NA
Cassava
 Breeding Provitamin A 100% target >75% >75% 50% ≥30%
 Fast-track Democratic Republic of Congo NA
Bean
 Breeding Fe 100% target 60% 40–50% 40–50%
 Fast-track Rwanda 40–50%
Rice, polished
 Breeding Zn 100% target 100% 75–100% 75–100% ≥30%
Wheat
 Breeding Zn 100% target 100% ≥30% ≥30%
Pearl millet
 Breeding Fe 100% target 100% 75–100% 50–75%
G × E, genotype × environment interaction.
NARS, National Agricultural Research Systems.
§ NA, not applicable.



View Full Table | Close Full ViewTable 4.

Examples of antinutrients in plant foods that reduce the bioavailability of essential trace elements and examples of major dietary sources (modified from Graham et al., 2001).

 
Antinutrients Essential micronutrient metal inhibited Major dietary sources
Phytic acid or phytin Fe, Zn, Cu, Ni Whole legume seeds and cereal grains
Certain fibers (e.g., cellulose, hemicellulose, lignin, cutin, suberin) Fe, Zn, Cu Whole cereal grain products (e.g., wheat, rice, maize, oat, barley [Hordeum vulgare L.], rye [Secale cereale L.])
Certain tannins and other polyphenolics Fe Tea [Camellia sinensis (L.) Kuntze], coffee (Coffea arabica L.), beans, sorghum [Sorghum bicolor (L.) Moench]
Hemagglutinins (e.g., lectins) Fe Most legumes and wheat
Goitrogens I Brassicas and Alliums
Heavy metals (e.g., Cd, Hg, Pb) Fe, Zn Contaminated leafy vegetables and roots



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Examples of substances in foods reported to promote Fe and Zn bioavailability and examples of major dietary sources (modified from Graham et al., 2001).

 
Substance Trace element Major dietary sources
Certain organic acids (e.g., ascorbic acid, fumarate, malate, citrate) Fe and/or Zn Fresh fruits and vegetables
Hemoglobin Fe Animal meats
Certain amino acids (e.g., methionine, cysteine, histidine) Fe and/or Zn Animal meats
Long-chain fatty acids (e.g., palmitate) Zn Human breast milk
Se I Seafoods, tropical nuts
β-carotene Fe Green and orange vegetables
Inulin and other nondigestible carbohydrates (prebiotics) Fe, Zn Chicory (Cichorium intybus L.), garlic (Allium sativum L.), onion (Allium cepa L.), wheat, Jerusalem artichoke (Helianthus tuberosus L.)



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Schedule of product release for biofortified products.

 
Crop Nutrient Countries of first release Agronomic trait Release year
Sweet potato Provitamin A Uganda, Mozambique High yielding, virus resistance, drought tolerance 2007
Bean Fe, Zn Rwanda, Democratic Republic of Congo Virus resistance, heat and drought tolerance 2010
Pearl millet Fe, Zn India Mildew resistance, drought tolerance 2011
Cassava Provitamin A Nigeria, Democratic Republic of Congo High yielding, virus resistance 2011–2012
Maize Provitamin A Zambia High yielding, disease resistance, drought tolerance 2011–2012
Rice Zn, Fe Bangladesh, India Disease and pest resistance, submergence tolerance 2012–2013
Wheat Zn, Fe India, Pakistan Disease resistance, lodging 2012–2013
Approved for release by national governments after 2–3 yr of testing.