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MOST3 , U.S. Agency for International Development Micronutrient Program, Arlington, VA 22209
2To whom correspondence should be addressed. E-mail: odary{at}istiinc.com.
| ABSTRACT |
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KEY WORDS: food fortification vitamin A micronutrients developing countries
| INTRODUCTION |
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Alternative strategies that frequently supply small but effective amounts of vitamin A [e.g., one third of the recommended daily intake (RDI)] over a prolonged time would be helpful. A diverse diet, which includes foods of animal origin that are rich in preformed vitamin A (esters of retinol), might be sufficient to satisfy the daily requirements of vitamin A. However, in most developing countries, diets are monotonous and mainly based on cereals and legumes that are poor sources of vitamin A. Even carotenoid-rich vegetables have low vitamin A bioavailability and bioefficacy (3
). Given these issues, food fortification with vitamin A can be an attractive and potentially effective and important intervention.
| History |
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These conditions are less common in the developing world, where food fortification has been infrequent or has ended after successful pilot trials. The potential of food fortification to reduce micronutrient deficiencies in developing countries was recognized >30 y ago (5
,6
). Levinson (5
) suggested considering unconventional carriers such as salt, sugar, seasonings and cooking oil, because the poorer segments of the population do not have access to other centrally processed foods, because they are sensitive to higher-priced fortified products, and because they have low purchasing power.
| Experiences with vitamin A fortification |
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| Oil |
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In Brazil, vitamin A added to oil was well absorbed when given along with a rice-based diet, and it significantly increased plasma retinol and liver stores (11
). Despite the potential advantages of fortifying oil with vitamin A, it has rarely been done for unknown reasons.
| Margarine |
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Several countries fortify margarine at levels ranging from 1 to 15 mg/kg as either a mandatory or a voluntary practice (9
). This provides 240% of the RDI, assuming a daily consumption of 15 g. The cost is similar to that of oil fortification. In the Philippines, an intentional fortification program prompted by public health interest has proven to be very efficacious. Star margarine, a product that does not require refrigeration and is made from a blend of coconut oil and hardened palm oil, is fortified with vitamin A to a level of 25 mg/kg (plus 3.5 mg/kg from ß-carotene). A field efficacy trial indicated that daily consumption of 24 g of this product, supplying 150% of the RDI for preschoolers and 100% for adolescents and adults, decreased the prevalence of low serum retinol (<0.70 µmol/L) in preschool-aged children from 25.7 to 10.1% after 6 mo of consumption. The product is now offered in the free market along with competing brands (13
). In India, a fortified hydrogenated oil, Vanaspati, has been available since 1953. Vanaspati is replacing ghee, or clarified butter, as the traditional oil. It is fortified with vitamin A at a level of 7.5 mg/kg and supplies 0.421% of the RDI depending on consumption levels (0.317 g/d) (14
).
| Cereal flours and meals |
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30% of the vitamin A RDI assuming a consumption of 80 g/d and 15% losses of the vitamin A during handling and storage of the flour, as well as food preparation. Biological evidence of the impact has not been published. The vitamin A compound used in corn flour fortification is a spray dry product (Roche, SD-250) that is water dispersible. The current cost of fortification is about US$1.40/MT, which is about 0.35% of the purchase price of flour, or a total of US$0.040/y per person.
In the Philippines, wheat flour used in making the popular bread pandesal is fortified with vitamin A (4.5 mg/kg) to produce a pandesal fortified at 2.8 mg/kg (16
). Daily consumption of 40 g of bread provides about 19% of the vitamin A RDI. Again, the vitamin A compound added is SD-250. Biological evidence of the impact was demonstrated by a significant increase in vitamin A liver stores of school children. The current cost of fortification is about US$2.75/MT, or US$0.040/y per person.
Other countries have carried out pilot studies to explore fortification of cereal flour or meal with vitamin A, but national programs are not in place. Wheat flour has been fortified with iron and B vitamins in the United States and other developed countries for >40 y (3
,4
). The U.S. Title II Food Aid Program (U.S.PL480) has been fortifying wheat flour with vitamin A (SD-250) since 1969 (17
). The fortification level has been established at between 6.6 and 7.9 mg/kg to provide 80100% of the RDI for consumption of 75 g/d and to ensure that the practice remains safe for people with higher consumption (17
).
However, vitamin A losses due to shipping and storage and during food preparation have not been considered. Losses have been estimated at 3050%, which are within the normal range of stability for vitamin A in dry fortified products (18
). This means that people who consume the products receive 4070% of the RDA of vitamin A. In 1993 it was estimated that adding vitamin A at the indicated level in wheat flour would cost US$3.79/MT (17
), that is US$0.104/y per person with an
1% increment in the purchase price.
| Sugar |
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The Institute of Nutrition of Central America and Panama developed appropriate technology, promoted legislation, and established national programs in three countries (Guatemala, Honduras and Costa Rica). The vitamin A compound that is being used is a gelatin-base beadlet (Roche, CWS-250; or BASF, CWD-250), which is bound to the sugar crystal through a layer of vegetable oil to avoid segregation (20
). To avoid promoting higher sugar consumption because of its fortification, it was initially forbidden to declare that the product contained added vitamin A (19
). A carefully designed evaluation in the mid-1970s in Guatemala conclusively demonstrated its effectiveness in reducing VAD (21
,22
). Nevertheless, the program was halted in 1979 because, although fortification was mandatory, the industry was not sufficiently motivated and there were also limitations to obtain foreign currency to purchase the fortificant. The program was resurrected in the harvest season of 1987 and has been sustained by full industry commitment.
VAD prevalence rates have been dramatically reduced (23
). Today, sugar in households in Guatemala and El Salvador contains an average of 9 mg of vitamin A per kilogram, which contributes 45180% of the vitamin A RDI for people older than 3 y of age (per capita sugar consumption ranges from 30 to 120 g/d). Sugar is now the main source of vitamin A even for infants and young children; it supplies
30% of the RDI. Prophylactic supplementation with vitamin A to children younger than 3 y of age has been maintained to ensure adequate intake (data published in national reports). Sugar is fortified at the sugar mills at a theoretical level of 15 mg/kg, but the content is near 9 mg/kg after preconsumption losses at the household level. After 9 mo of shipping and storage, 4070% of the vitamin A is estimated to remain in sugar, depending on the climatic conditions. The cost of fortification to the industry amounts to $9.18 per MT (24
), which is about US$0.20/y per person and represents about 2% of the retail price of sugar. In the Central American countries, the actual cost per person is higher (US$0.32) because all sugar, regardless of its final use (domestic or industrial), is fortified to ensure that most of the population will receive the fortified product.
| Monosodium glutamate |
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The efficacy of MSG fortified with vitamin A was demonstrated in the Philippines (25
) and Indonesia (26
). In the former, the fortification level was 2047 mg/kg to supply all the RDI required by MSG consumers. To avoid raising the purchasing price, the contents of the sachets were reduced from 2.4 to 2 g (reducing the amount of MSG by 17%). People recognized the lower than usual MSG amount and preferred the nonfortified product. The use of vitamin A as SD-250 caused discoloration (vitamin A is yellowish; MSG is white) and it separated from the MSG crystals. This was not a serious problem with small sachets, but it was unacceptable in large packs. In addition, the finely pulverized MSG intended to preserve the white color interfered with hermetic seals of the sachets.
In Indonesia, some of the technological difficulties were overcome (26
). Part of the solution was to reduce the vitamin A level to 810 mg/kg with the aim to provide
50% of the RDI. Children consumed 0.24 g/d of MSG and adults consumed 0.4 g/d. At the time of consumption, 57% of the vitamin remained in the product, so the MSG provided only
30% of the RDA for vitamin A. MSG was selected because it was centrally processed, it reached the target population and the consumption varied little. Assuming a cost similar to that of sugar, it is estimated that the cost of fortification would be US$575/MT. If the retail price of MSG is US$5/kg, then the increment in the price due to fortification should be 11.5%, which is relatively high to compete against the nonfortified product in the free market. Nevertheless, the current annual cost per person remains relatively low at about US$0.050.
| Other foods |
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Other types of fortified products are complementary foods aimed at infants or school feeding programs. Biscuits and beverages fortified with multiple micronutrients, including vitamin A, are used in school feeding programs in Mexico, Central America, Indonesia and Peru.
A successful product need not be one consumed in large measure by the youngest children. If it is consumed by women, improving their vitamin A status and therefore the vitamin A content of their breast milk, it will play a major role in ensuring improved vitamin A status of young, breast-fed children during the critical first 2 y of life (31).
| Critical elements of successful programs |
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| Identification of potential vehicles |
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The quantity of food consumed is very important; otherwise the vitamin A concentration may be too high, causing technical and cost problems. In practice, oils, hydrogenated oils, cereal flours and sugar should be fortified at no more than 20 mg/kg. Vitamin A losses during production, storage and handling increase program expense. In addition, a high concentration of vitamin A increases the potential for individuals who consume large amounts of the product to consume too much vitamin A. Table 1
shows the estimated vitamin A levels, at different consumption patterns, to meet distinct portions of the RDI. Consumption of 5 g of any food fortified with vitamin A (at a level of 18 mg/kg at the consumer table) would provide 15% of the RDI; 10 g would provide 30%. Therefore, any food consumed in amounts <5 g a day is difficult to be considered as suitable for food fortification.
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Despite urbanization trends and the concomitant increase in consumption of commercially processed foods, finding suitable vehicles for fortification in the less-developed countries where VAD is endemic has been difficult.
| Keeping track of economic, market and trade issues |
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Table 2
shows that all described programs (oil, margarine, cereal flours, sugar and MSG) are very cost effective. The cost per person per year (supplying at least 30% RDI) ranges from US$0.008 for oils and margarine to US$0.121 in the case of sugar. These data show that food fortification is a cost-effective way to provide vitamin A to the people who need it. Furthermore, the data also suggest that oils are the most suitable candidates for carrying vitamin A, because marginal costs are increased the least. The annual cost to supply the same amount of vitamin A through MSG is similar to that for cereal flours and sugar, but the margin of increase in the product price is very different: 0.26% for flours, 1.39% for sugar and 25.3% for MSG. Therefore, fortification of MSG is very unappealing to producers, because the fortified product cannot compete with the nonfortified one, unless the government mandates fortification by all producers or prices are maintained by subsidies.
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| Establishing and enforcing regulatory instruments |
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| QA/QC and monitoring systems |
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| Documenting program effectiveness for sustained commitment |
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| Voluntary and consumer-driven fortification |
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The American Dietetic Association points out that exceeding intake recommendations provides no demonstrated benefit for healthy people (32
). In the case of fortification with vitamin A, it would be adequate to recommend voluntary fortification to provide 1530% of the RDI,
90180 µg of REs per serving. In the special case of complementary foods for infants and small children, who have the greatest need to improve their vitamin A intake, the level of acceptance might be set up to 3060% of the specific RDI (i.e., 120240 µg RE per serving).
Even with mandatory fortification, campaigns are important to strengthen the commitment of government and industry, to maintain or increase the demand and consumption of the fortified food and to remove any fears about vitamin A toxicity. An educated consumer is needed to achieve the long-term goal of consumer-driven fortification, and systematic education and social marketing will play an important role to this end. The health messages for iodized salt in the United States provide a good example. The fortified product is labeled, "This salt supplies iodide, a necessary nutrient," and the nonfortified product says, "This salt does not supply iodide, a necessary nutrient." The challenge is more critical in the developing world, where vast sectors of the population are illiterate and food selection is based on price rather than quality.
| Fortification as part of an integrated approach to VAD |
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| CONCLUSION |
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The traditional elements of a potential food matrix for fortification are a) regularly consumed by the target population, b) produced by a few factories in a centralized fashion, c) without sensorial changes compared with the nonfortified equivalent and d) retain adequate stability and bioavailability4 at the point of consumption. In the case of vitamin A, it is important that the typical amount consumed by the target population be large enough. For oil and hydrogenated oils, the consumption should be at least 5 g/d (1.8 kg/y), and for cereal flours and sugar it should be at least 15 g/d (5.5 kg/y). The purpose is to keep the increase in cost due to fortification within an acceptable range and to avoid supplying unnecessary amounts of vitamin A to high-consumption individuals.
In terms of cost-effectiveness, attention should first focus on oils and hydrogenated oils (e.g., margarine), then on cereal flours and finally on sugar and similar products. Cereal flours have the additional advantage that they permit addition of other micronutrients at the same time, reducing the overall cost of the fortification process.
Fortification level
The concentration of vitamin A in the food vehicle depends on the biological goal and the typical amount of the food vehicle consumed. In general, it is advised that the amount of vitamin A supplied through fortification meets at least 15% the RDIs for the target group (e.g., individuals consuming the lowest amount of the fortified food). This amount divided by the daily ration determines the minimum level of fortification estimated at the household level. The minimum level of fortification at retail stores should include an overage of 1020%. Industries must estimate an adequate overage to add during production to account for anticipated losses during handling, shipping and storage. For example, if the intention is to provide 180 µg of vitamin A to a population whose sugar consumption is 50 g a day, the sugar marketing time is 6 mo and 50% of the added vitamin A remains in the product during that period, then
4.5 mg/kg. Note that all these values are minimum criteria, because it is easier to examine discrete cut-off points than averages.
Vitamin A level for voluntary fortification
Urbanization and economic globalization are encouraging some industries to improve the perceived value of their products through fortification, which could lead to many more persons achieving the RDI of vitamin A. Infants and small children, whose nutritional needs of micronutrients might remain unmet through fortification of food staples, could get additional benefits from consuming fortified complementary foods. It is necessary to regulate that practice. It is recommended that voluntarily fortified foods provide 1530% of the vitamin A RDI per serving (90180 µg RE). In the case of complementary foods for small children, the limits might be higher; 3060% of the specific RDI seems adequate (i.e., 120240 µg RE per serving).
Regional accords
The increasing attention to market globalization and free-trade agreements requires that neighboring countries with similar conditions adopt the same technical standards for food fortification. This strategy would reduce conflicts between the health and the industrial/trade sectors.
Because of insufficient resources in developing countries to ensure enforcement of the fortification requirements, and because the population with the greatest need tends to select foods based on price rather than quality, fortification of commodities should follow a mandatory and universal system.
Monitoring and evaluation systems
One of the weak points of ongoing food fortification programs is the lack of data about quality, coverage and impact. A practical and effective system of monitoring should be required from conception of the program. It is important to establish an annual household surveillance system to obtain process indicators such as coverage, quality and consumption of fortified foods by consumers. This system would serve as the main means to confirm that the program is reaching the expected outputs. It is also important to periodically evaluate the biological impact of the programs (effectiveness). As a strategy to keep the interest of industry, government and consumers focused on maintenance and improvement of the fortification programs, the information should be systematized and published. Strengthening government capacity in these fields is an urgent need. Establishing an external monitoring system through consumer protection societies, where possible, might serve as an additional force to ensure quality and coverage.
Systematic advocacy and sensitization to industry, government and consumers
Social marketing activities regarding the benefits of the food fortification programs should receive special consideration, especially in countries where free trade policies are pursued aggressively. These activities should reach all players: industry, government and consumers. A successful food fortification program is the product of a concerted action among all these players.
Targeted supplementation and other strategies
Food fortification is an efficient and cost-effective strategy to improve the vitamin A status of populations. Nevertheless, some groups, because of age or geographical isolation, escape coverage. Therefore, other focal interventions are often needed. For example, periodic supplementation aimed at children younger than 36 mo of age could complement universal fortification of staples. In turn, fortification of staples might make it less necessary to supplement postpartum women.
| FOOTNOTES |
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3 Abbreviations used: IU, international unit; MOST, the U.S. Agency for International Development Micronutrient Program; MSG, monosodium glutamate; MT, metric ton; QA/QC, quality assurance/quality control; RDI, recommended daily intake; RE, retinol equivalent; VAD, vitamin A deficiency. ![]()
4 It is unnecessary to check vitamin A (retinol) bioavailability in each case, because there is sufficient evidence that its absorption and bioefficacy is very high. ![]()
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