Luis A. Mejia
Nutrient supplementation of foods was mentioned for the first time in the year 400 B.C. by the Persian physician Melanpus, who suggested adding iron filings to wine to increase soldiers' "potency." In 1831 the French physician Boussingault urged adding iodine to salt to prevent goitre. However, it was between the First and Second World Wars (1924-1944) that supplementation was established as a measure either to correct or prevent nutritional deficiencies in populations or to restore nutrients lost during food processing. Thus, during this period the adding of iodine to salt, vitamins A and D to margarine, vitamin D to milk, and vitamins B1, B2, niacin, and iron to flours and bread was established.
Currently, food fortification encompasses a broader concept, and might be done for several reasons. The first is to restore nutrients lost during food processing, a process known as enrichment. In this case, the amount of nutrients added is approximately equal to the natural content in the food before processing. A second reason is to add nutrients that may not be present naturally in food, a process known as fortification. In this case, the amount of nutrient added may be higher than that present before processing. Fortification also standardizes the contents of nutrients that show variable concentrations. A typical example is the addition of vitamin C to orange juice to standardize vitamin C concentration and compensate for changes due to seasonal and processing variations. Finally, for technological purposes, a preservative or colouring agents are added to processed foods.
Therefore, depending on the reasons for adding nutrients, the objectives may be: to maintain the nutritional quality of foods, keeping nutrient levels adequate to correct or prevent specific nutritional deficiencies in the population at large or in groups at risk of certain deficiencies (i.e., the elderly, vegetarians, pregnant women, etc.); to increase the added nutritional value of a product (commercial view); and to provide certain technological functions in food processing.
According to these principles, currently in several countries nutrients are added to a wide variety of food carriers, such as cereals, flours, bread, milk, margarine, infant formulas, soy milk, orange juice, salt, sugar, monosodium glutamate, tea, dietetic beverages, and even parenteral and enteral solutions (table 1). Most fortifying agents are vitamins and minerals, and in some cases essential amino acids and proteins. These additions have helped to solve public health problems, such as salt iodization to prevent goitre .
The words enrichment and fortification have historical origins. Enrichment was originally introduced in the 1940s with enactment of the Standards for Enrichment Programs aimed at replenishing nutrients lost during cereal processing. This was expanded into a broader context to include nutrients not naturally present in the food, or fortification. Currently, the two words are often used interchangeably, which is wrong from a historical standpoint. However, taking into consideration the fact that the aim in both cases is to improve the nutritional value of foods, the term nutrification was suggested, which would include both enrichment and fortification .
TABLE 1. Fortified foods
In specific intervention programmes the addition of nutrients has successfully reduced or even eradicated a particular deficiency. The technology for most of these programmes is readily available, and it is well known that political decisions and know-how guarantee success. For example, in the Central America region, fortification of sugar with vitamin A has effectively reduced the prevalence of hypovitaminosis A in the population.
To maximize the success of such programmes, several factors must be taken into consideration. The carrier has to be a staple food of the target population. Also, centralized processing is necessary, and frequent as well as reasonably constant consumption is desirable. The nutrient or fortifying agent must have adequate physicochemical, organoleptic, and bioavailability characteristics. This means that the colour, taste, odour, and appearance of the carrier food must not be affected. Bioavailability is extremely important. In the case of vitamins it is not a problem, but it is when minerals are added.
Another important issue is related to the cost of the fortifying agent. It is desirable that the fortification process does not significantly increase the total cost of the final product. Furthermore, it is necessary to have a monitoring and control system that guarantees both adequate nutrient concentration and programme compliance. It is also important to verify the adequate addition of nutrients to ensure the programme's effectiveness, and, in the case of potentially toxic nutrients, to guarantee that excessive concentrations are not added, which could put the population at risk. Several questions must be answered in relation to legal issues. Should the programme be compulsory or voluntary? Should it be financed by the government, the private sector, or both? In view of previous unsuccessful experiences, where food-fortification programmes were mandatory but failed to secure compliance, it becomes necessary to identify different approaches for adequate implementation, possibly including fiscal and tariff incentives. It is also important to demonstrate and document the cost-benefit of the intervention in order to gain objective evidence to support the continuance of these programmes .
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