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Similarly, in many countries, vitamin A fortification of sugar and iron fortification of wheat flour have been made mandatory.
Fortification is best done through food items regularly consumed by most of the population. Salt, sugar, cereals, edible oils, and milk have been commonly used as fortification carriers. There are several technical aspects that determine the choice of carrier and the fortificant used to deal with a particular micronutrient deficiency. Bio-availability and absorption of a micronutrient depend on the fortificant and carrier used. For example, absorption of iron from ferrous sulphate, the most common fortificant used for iron, is negatively related to the bran content of flour as bran inhibits the absorption of iron. In the case of iodine, iodine is lost to the atmosphere in the event of exposure to moisture, heat, and sunlight. Potassium iodate is known to be a more stable fortificant than potassium iodide and sodium iodide. The stability of iodized salt can also be improved by the use of stabilizers and good packaging (Biber, Unak, and Yurt, 2002; Diosady et al., 1998; Kelly, 1953). Some fortificants affect the physical properties Fortification and Supplementation 63 of food, like taste and colour, and thus may not be readily accepted by target populations. In the 1970s, Guatemala introduced sugar fortified with NaFeEDTA. However, NaFeEDTA changed the colour of foods and beverages to which the fortified sugar was added, resulting in its poor acceptability. The introduction of colour-neutral iron fortificants in Brazil, on the other hand, has been much more successful (Beinner and Lamounier, 2003; Pineda, 1998). There are also significant differences in the costs of different fortificants (Allen et al., 2006).
Fortification has been most successful in addressing iodine and vitamin A deficiencies. Iron, folate, and zinc fortifications have also been widely used;
although the success of such programmes has been mixed.
A review of the literature on fortification programmes across the world suggests that fortification is most successful where the cost of fortification is a relatively small share of the total cost of the product. Darnton-Hill et al.
(1999) point out that the fortification of wheat flour in Latin America added less than 0.5 percent to the retail price of flour. The high costs of fortification make it commercially less attractive as fortified foods cannot be priced much higher than unfortified products (Bressani, 2000; Darnton-Hill et al., 1999;
Fortification has been most successful where the food item being fortified is produced on a large scale by a few private or public producers (Bressani, 2000). In countries where local small-scale grain milling is common, fortification is more difficult to implement and regulate. Implementation of vitamin A fortification of sugar in many Latin American countries and salt iodization in many countries across the world has been feasible because sugar and salt are mainly manufactured in the organized sector. On the other hand, the impact of iron and folate fortification of flour on the prevalence of iron-deficiency anaemia has been mixed. In most Latin American countries, wheat milling is highly centralized, large scale, and in the organized sector. Most of these countries have made wheat fortification mandatory. This has been implemented relatively effectively because of the organized nature of wheat milling (Bressani, 2000; Darnton-Hill et al., 1999).
On the other hand, iron fortification of maize flour has been limited, not only for technical reasons, but also because the milling of maize, in particular wet milling, is much more decentralized and small-scale than wheat milling.
Traditionally, maize is used in Latin America after nixtamalization, which involves boiling and soaking maize with lime before grinding it wet into a dough. The process has been industrialized to a significant degree through introduction of nixtamalized corn flour as a substitute for wet-ground corn (maize) dough. This has opened the possibilities of iron fortification of maize flour in Latin America (Bressani, Rooney, and Salvidar, 1997).
64 Ending Malnutrition Box 4.1 Eradicating Iodine Deficiency through Mandatory Iodine Fortification of Salt Iodine deficiency causes diseases like goitre and nodular hyperthyroidism, and results in reduced productivity. It leads to cognitive impairment among children. Iodine-deficient pregnant women face a higher risk of abortion, a higher probability of having babies with low birth weight and a higher probability of infant mortality (Speeckaert et al., 2011). In 1990, the World Health Assembly accepted the elimination of iodine deficiency as a public health goal for all countries.
Various supplementation and fortification methods have been implemented across the world to deal with iodine deficiency. In 1994, a UNICEF– WHO Joint Committee endorsed iodized salt as a safe and effective strategy for ensuring sufficient intake of iodine by all persons.
The process of iodization is simple and cost-effective, and does not alter the taste, odour, and colour of salt. Given that salt is universally consumed, it is considered an excellent vehicle for iodine.
Health policies mandating iodization of salt have seen remarkable progress in improving iodine status and reducing the prevalence of goitre and cretinism in countries with severe iodine deficiencies. In South Africa, iodization of salt has resulted in the near-eradication of iodine deficiency in schoolchildren after one year of implementation (Jooste, Weight, and Lombard, 2000). The long-term supply of iodized salt in regions of Pakistan where goitre is endemic resulted in significant decreases in its prevalence. The proportion of severely iodine deficient households was reduced to a marginal level with constant monitoring and adjustment in iodine supplementation levels (Ali et al., 1992). Essentially, periodic monitoring of iodine status in women and children is imperative to ensure the efficacy of iodine fortification.
The Swiss population witnessed dramatic reduction in the prevalence of goitre with the consumption of iodized salt (Allen et al., 2006). Regular monitoring helped the government in Switzerland to achieve sufficient iodine nutrition in women and children by changing the concentration of iodine in salt in response to the changing dietary habits of the population (Zimmermann et al., 2005).
As iron deficiency reduces the efficacy of iodine fortification (Allen et al., 2006), some countries have used double fortification of salt with iodine and iron. A review of evidence suggests that while double fortification improves the absorption of iodine, it diminishes the stability of iodine in salt, and the iron intake through salt only partially covers iron requirements (Baxter and Zlotkin, 2015).
There are three main concerns with the use of iodized salt as the main means for dealing with iodine deficiency. First, iodine has limited stability and tends to dissipate over time because of exposure to moisture, light, and heat.
Good packaging and storage, which improve stability considerably, remain a problem in developing countries and at the household level.
Secondly, strong evidence links high salt intake to hypertension and other cardiovascular problems (WHO, 2012). A WHO–FAO Joint Expert Consultation recommended that salt intake be reduced to 5 grams per day Fortification and Supplementation 65 per person (WHO/FAO, 2003). Unless the concentration of iodine in salt is adequately increased, reduced salt intake would reduce intake of iodine. A decline in iodine intake and reappearance of iodine deficiency have already been noticed in some developed countries on account of inadequate intake of iodine (Renner, 2010). However, increasing the concentration of iodine reduces its stability, making it difficult to use salt as the main vehicle for the delivery of iodine. Further research is required to develop technology to increase the concentration of iodine in salt without adversely affecting iodine stability and other properties, and to find other suitable carriers for iodine.
Finally, salt fortification becomes difficult to implement and monitor where salt production is decentralized. This is important, for example, in coastal areas, where sea salt is locally produced. Rasheed et al. (2001) have shown that only 2 percent of households consumed iodized salt in the coastal regions of Bangladesh. The easy availability of untreated salt at lower cost and lack of awareness of the health effects of iodized salt are the main factors that limit the use of iodized salt in the coastal areas of Bangladesh.
Figure 4.1 Proportion of households consuming adequately iodized salt, by country, 2000–13 In all, it is estimated that about 75 percent of households worldwide use adequately iodized salt.
Among the regions, East Asia and the Pacific has the highest proportion – 87 percent – of households consuming adequately iodized salt, close to the global target of 90 percent salt iodization. In all, 69 countries reached the target of 90 percent coverage of salt iodization by 2011 (UNICEF, 2013 and Figure 4.1). While commendable, it is critical to maintain the momentum to ensure iodized salt for the remaining population of the world. Universal use of adequately iodized salt requires research coordination for technical improvements, introduction of mandatory provisions, expanding awareness-raising, as well as careful regulation and monitoring at the national level to overcome administrative, social, medical, and other barriers to eradicating iodine deficiency.
66 Ending Malnutrition On the other hand, in many Asian and African countries with large rural populations, a substantial part of the food consumed by households is homeproduced, and grain milling is decentralized and on a small scale. These make implementation and regulation of fortification more difficult, and its reach across the target population more limited. Although there have been some experiments in distributing pre-mixed nutrients for home fortification, in most of these countries, fortified flour constitutes a relatively small share of total consumption.
Although the fortification of salt and sugar has been relatively successful in many countries, an important concern is that the promotion of fortified salt and sugar could work against attempts to reduce salt and sugar intake by the population. It is, therefore, recommended that promotion of iodized salt and programmes for reducing salt intake should closely collaborate to ensure that promotion of the use of iodized salt does not result in public promotion of salt intake (WHO, 2008). Some writings on iron fortification have advocated the use of soft drinks as a vehicle for iron fortification to deal with iron-deficiency anaemia among children and women (Layrisse et al., 1976; Wojcicki and Heyman, 2010). Such arguments ignore the serious dietary imbalances and public health problems caused by increasing the intake of sugar-dense beverages. Promoting sugar-dense beverages as a vehicle for dealing with iron-deficiency anaemia carries a serious risk of inducing excess sugar consumption.
Fortification is a cost-effective method of enriching diets to deal with specific deficiencies. Fortification may be particularly useful in the short run for populations that buy centrally processed foods. There are, however, limitations of fortification in reaching rural consumers for whom much of the basic diet is produced at home. When micronutrient requirements vary across the population (say, between men, women, and children), fortification can only be used to meet the minimal requirement, and may have to be combined with additional interventions for groups that need additional intake of micronutrients.
Agronomic biofortification Another approach to augment the nutrient content of food is through fortification at the stage of crop production itself. This can be done either through application of nutrients along with fertilizers or irrigation water, or by developing crop varieties and hybrids that are rich in a particular nutrient.
Deficiencies of micronutrients, for example, zinc and iodine, can be traced in many countries to the depletion of these nutrients in the soil.
Fortification through soil enrichment is known to be an effective way of dealing with zinc, iodine, and selenium deficiencies (Alloway, 2009;
Cakmak, 2008, 2009; Rengel, Batten, and Crowley, 1999).
Fortification and Supplementation 67 In the Central Anatolia region of Turkey, fertilizers enriched with zinc were used for cultivation of zinc-absorbent wheat varieties (Cakmak et al., 1999). It has been argued that zinc enrichment of fertilizers can go a long way in dealing with zinc deficiencies in India, where about half the soils are deficient in zinc (Cakmak, 2009). Hence, the Government of India has introduced additional subsidies to fertilizer manufacturers for zinc fortification of fertilizers, and to farmers for using zinc fertilizers (Das and Green, 2013).
In China, potassium iodate was added to canal irrigation water to enrich the soils with iodine (Cao et al., 1994). The empirical evidence showed that the iodination of canal water significantly reduced iodine deficiency among pregnant women, which in turn resulted in a significant drop in infant and neonatal mortality (DeLong et al., 1997).
Since the mid-1980s, sodium selenate has been used to enrich fertilizers in Finland. This is known to have helped improve selenium intake in Finland (Aro, Alfthan, and Varo, 1995; Varo et al., 1988).
Fortification through soil enrichment is particularly useful where the consumption of staple grains for a large proportion of households is based on home production. In such cases, the fortification of flour at the stage of milling may not be effective. Agronomic fortification is effective and can be introduced relatively quickly without major new investments in research and extension.