ZINC FORTIFIED FOODS
Feb 21 - 27, 2011
Food fortification is the public health policy of adding micronutrients (essential trace elements and vitamins) to foodstuffs to ensure that minimum dietary requirements are met. Simple diets based on staple foods with little variation are often deficient in certain nutrients, either because they are not present in sufficient amounts in the soil of a region, or because of the inherent inadequacy of the diet.
Addition of micronutrients to staples and condiments can prevent large-scale deficiency diseases in these cases. Several ranges of food supplements are recognized:
* additives which repair a deficit to "normal" levels
* additives which appear to enhance a food
* supplements taken in addition to the normal diet
Food Supplements: There are several main groups of food supplements which can be considered:
* Vitamins and co-vitamins
* Essential minerals
* Essential fatty acids
* Essential amino acids
EXAMPLES OF FORTIFIED FOODS
Iodised salt is in use in the United States before World War II. Folic acid is added to flour in many industrialized countries, and has prevented a significant number of neural tube defects in infants. It is, however, not uniform in its application, with more intake of folic acid through fortified flour among those who were already receiving high amounts through their diet.
Niacin has been added to bread in the USA since 1938 (when voluntary addition started), a programme which substantially reduced the incidence of pellagra.
Vitamin D is added to a few foods (especially margarine).
Fluoride salts are added to water and toothpastes to prevent tooth decay. Water fluoridation is a controversial topic in some segments of the public, although less so amongst established scientific bodies.
Calcium is frequently added to fruit juices, carbonated beverages and rice.
Golden rice is a variety of rice which has been genetically modified to produce beta carotene. Amylase rich flour is utilized for food making.
WHY FOOD FORTIFICATION?
Food fortification is defined as the addition of nutrients to commonly eaten foods, beverages, or condiments at levels higher than those originally found in food, with the goal of improving the quality of the overall diet. In industrialized countries, fortification has played a major role in increasing the dietary intake of those micronutrients for which deficiencies are common and of public health concern; the contribution of fortification programs to the virtual elimination of micronutrient deficiencies in these countries is widely acknowledged.
In lower income countries, fortification is increasingly recognized as an effective approach to improving the micronutrient status of the population. Relative to other approaches, fortification is thought to be the most cost effective means of overcoming micronutrient malnutrition.
WHO and FAO published in 2006 the Guidelines on Food Fortification with Micronutrients (WHO/FAO 2006). These general guidelines, written from a nutrition and public health perspective, are a resource for governments and agencies implementing or considering food fortification and a source of information for scientists, technologists and the food industry. Some basic principles for effective fortification programs along with fortificants' physical characteristics, selection and use with specific food vehicles are described. Fortification of widely distributed and consumed foods has the potential to improve the nutritional status of a large proportion of the population, and neither requires changes in dietary patterns nor individual decision for compliance.
Worldwide, more than 600 million metric tons of wheat and maize flours are milled annually by commercial roller mills and consumed as noodles, breads, pasta, and other flour products by people in many countries. Fortification of industrially processed wheat and maize flour, when appropriately implemented, is an effective, simple, and inexpensive strategy for supplying vitamins and minerals to the diets of large segments of the world's population. Flour fortification programs should include appropriate Quality Assurance and Quality Control (QA/QC) programs at mills as well as regulatory and public health monitoring of the nutrient content of fortified foods and assessment of the nutritional/health impacts of the fortification strategies. Though the wheat and maize flours can be fortified with several micronutrients, the technical workshop focused on iron, folic acid, vitamin B12, vitamin A and zinc, which are five micronutrients recognized to be of public health significance in developing countries.
Wheat and maize flour fortification is a preventive food-based approach to improve micronutrient status of populations over time that can be integrated with other interventions in the efforts to reduce vitamin and mineral deficiencies when identified as public health problems. However, fortification of other appropriate food vehicles with the same and/or other nutrients should also be considered when feasible. Wheat and maize flour fortification should be considered when industrially produced flour is regularly consumed by large population groups in a country.
Fortification programs represent long-term strategies that may effectively prevent the development of nutrient deficiencies among recipients, although fortification alone may not be adequate to treat existing deficiencies. Where the micronutrient deficiency is widely distributed in the population, national level mass fortification of centrally processed foods is an appropriate strategy. An example of a country with a nationwide zinc fortification program is Mexico, where zinc and other micronutrients are added to wheat and maize flours that are used in preparing bread and tortillas, the two principal staples in the country. In cases where large segments of the population at risk do not have ready access to centrally processed foods, fortification may also be implemented at the community level. With the latter strategy however, cost is higher, sustainability is uncertain, and quality assurance and control and governmental enforcement are more difficult to achieve. Targeted fortification programs can be developed to increase the intake of zinc or other nutrients by specific segments of the population who are at elevated risk of zinc deficiency such as infants, young children, or pregnant and lactating women.
In this case, special-purpose foods, such as infant cereals, other processed infant foods, or foods distributed in school lunch programs can be fortified and distributed or made available in the regular marketplace. There are several examples of adding zinc to foods in targeted fortification programs.
DEVELOPING SUCCESSFUL FORTIFICATION PROGRAMS
The government, the food industry, and the research community all play key roles in developing successful fortification programs; cooperation among these three groups is extremely important for programmatic success and should be sought at an early stage of program development. A committee comprised of representatives of these groups should be created for planning, designing, promoting, regulating, and supervising fortification programs. Examples of the roles played by each of the different participants in such programs are as follows:
• Government initiates, coordinates, regulates, enforces, and monitors programs.
• Scientific community determines the prevalence of zinc deficiency, the sensory acceptability and efficacy of the chosen zinc compound and food products, and the overall effectiveness of the program.
• Food industry helps define feasible, affordable fortification strategies and identify appropriate food vehicles and fortificants develop quality assurance systems and implement educational campaigns to reach target populations.
CONSUMER ACCEPTABILITY OF THE ZINC-FORTIFIED FOODS
Sensory trials are necessary to determine whether the chosen zinc compound and the level of fortification alter the consumer acceptance of the fortified product. For example, if fortification alters the taste, aroma, or cooking properties of foods, these foods may be rejected by targeted groups. Sensory trials can also be used to compare organoleptic qualities and consumer acceptance of products fortified with different forms of zinc and at different levels of zinc fortification. Available information indicates that the use of recommended amounts of zinc fortification does not adversely affect the sensory properties of the foods that have been tested.
DETERMINING THE ABSORPTION OF ZINC FROM FORTIFIED FOODS
Some potential food vehicles may have high amounts of inhibitors of zinc absorption, such as phytate and the absorption of zinc fortificants varies when added to different foods. Since experience with zinc fortification is limited, it is worthwhile to conduct absorption studies; these studies should use appropriate zinc isotopic tracers to quantify the absorption of different fortificants used in candidate vehicles before final selections of fortificants and vehicles are made unless relevant information is already available.
The quality of the fortified product also must be monitored on a regular basis, both at the level of the production site and at the point of purchase, to ensure that it contains an appropriate amount of the fortificant. Food control is carried out in two phases: quality control and assurance by the manufacturers and enforcement in factories, importation sites, and markets by the government. The latter set of activities includes auditing and inspection, which should be supported with analyses by reliable food control laboratories.
MONITORING AND EVALUATION ISSUES
Once the fortification program is in place, the effectiveness of the program to reduce zinc deficiency in the target group must be monitored and evaluated. A system should be created to monitor changes in population zinc status periodically.
SCIENTIFIC EVIDENCE OF ZINC FORTIFICATION
The available studies clearly show that zinc fortification can increase total daily zinc absorption. Thus, it is reasonable to conclude that individuals at risk of zinc deficiency who consume zinc-fortified foods will have enhanced zinc status. Most absorption studies also show that adding zinc to food does not adversely affect the absorption of other minerals like iron. Despite the known positive impact of zinc fortification on total zinc absorption, studies available to date in young children have not shown a positive effect of zinc fortified complementary foods on indicators of young children's zinc status, growth or other zinc-related functional responses, so additional research is needed. Among schoolchildren, however, two studies have found a positive impact on their serum zinc concentration.
In summary, zinc fortification appears to be a promising strategy to control zinc deficiency in terms of technical feasibility, cost, safety and impact on total zinc absorption, although there is currently limited empirical evidence of a positive effect of zinc fortification programs. Therefore, the nutritional and health impacts of zinc fortification programs should be rigorously evaluated.