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The addition of vitamins, mineral nutrients and amino acids to foods is controlled through the Food and Drug Regulations (FDR) to help ensure that Canadians get sufficient but not excessive amounts of certain nutrients in their diet. The FDR prescribes the foods to which vitamins, mineral nutrients and amino acids may or must be added and associated levels. Refer to Food labelling for industry: Fortification for more information.
The over or under addition of a nutrient to food, and the loss of a nutrient before the end of the expected shelf-life of a food, can have health consequences for certain individuals. These consequences can range from minor to serious (for example, weakness, slight skin discoloration, rickets, brain abnormalities). The degree and nature of the consequences depends on the individual, the level of nutrient, and the nature and type of nutrient deficiency or excess. For example, infants are a high risk for malnutrition when infant formulas and human milk fortifiers do not provide the intended level of nutrients for the duration of the product shelf-life. Vitamins such as vitamin A can be toxic and dietary components such as iron can cause gastrointestinal distress when too much is ingested.
Consult the document Good manufacturing practices for infant formula (2021) for information on control measures you can apply to ensure the consistent quality, safety and nutritional adequacy of infant formula products. The information in this document can also apply to human milk fortifiers.
Nutrient stability and degradation
Nutrient stability under normal conditions of storage and use is one of the important factors in determining the effectiveness of a food fortification process. From a food manufacturing standpoint, nutrition stability during formulation, preparation, processing, transportation and storage is very crucial in determining the effective production of fortified foods. [4]
Compared with vitamins, minerals are more stable under extreme processing conditions. The primary mechanism of mineral loss is through leaching of water-soluble minerals. Regarding vitamins, their stability is affected by a number of factors such as temperature, moisture, oxygen, light, pH, minerals (especially iron and copper), vitamin-vitamin interactions, and other food components. However, given their chemical heterogeneity, vitamin losses in different foods vary considerably during both processing and storage of the final product. [5, 6]
For example, vitamin A is very susceptible to degradation because there are many double bonds in its chemical structure. It is particularly sensitive to atmospheric oxygen and low acidity, i.e. pH below 5.0. Significant losses of vitamin C may occur due to the release of ascorbate oxidase from the plant tissue as vegetables wilt or when they are cut. Significant losses of vitamin C may also occur in cooking, both through leaching into the cooking water and atmospheric oxidation. Like other water-soluble vitamins, vitamin B1 is readily lost by leaching into cooking water. Furthermore, it is unstable to light (e.g., much or all of this can be lost when baked goods are exposed to sunlight in a shop window). This vitamin is also destroyed by sulphites (in sulphites-treated potato) and polyphenols (tannic acid in tea and betel nuts). [7]
With respect to multiple fortifications, the presence of iron and copper accelerates degradation of vitamins, especially vitamins C, A, and B1, due to their multiple oxidation states. Fortification with several vitamins may also give rise to vitamin-vitamin interactions that may accelerate the rate of breakdown of some vitamins with the best known being those among vitamins C, B1, B2, B12 and folic acid. [24] Nevertheless, the extent of these interactions is dependent on the nature of the food product as well as on factors such as temperature, moisture level, pH and light, during processing and storage of the final product.
In order to maintain the micronutrient levels throughout the product's shelf-life, the amount of vitamins added during processing needs to be higher than the amounts declared on the label in some cases. The difference between the declared and formulated vitamin levels, termed "overage", will be different for each food application. However, the overage level should not be so high as to cause a toxic response. The following are important points for the manufacturers of fortified foods to consider:
- extent to which food processes and distribution systems could affect nutrition retention
- strategies for minimizing the losses caused by nutrient instability
- decision on whether a nutrient statement or content claim can be made on labels and advertising based on the amount of nutrients through the product's shelf-life
- evaluation of the choices and supply of nutrients based on nutrient stability data
To minimize nutrient degradation and losses, proper processing technology needs to be implemented at the manufacturing level. Some strategies for stabilizing nutrient content include the application of a protective coating for the individual nutrient; the addition of antioxidants; the control of temperature, moisture, and pH; and protection from air, light, and incompatible metals during processing and storage. The degree of nutrient degradation in food and the length of the shelf-life will govern the level of overage. [4]
References
- [1] Ross, A. Catharine. "Modern nutrition in health and disease". Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2014.
- [2] U.S. Food and Drug Administration. Good Manufacturing Practices (GMPs) for the 21st Century - Food Processing. Section Two: Literature review of Common Food Safety Problems and Applicable Controls. Washington DC: U.S. Food and Drug Administration, 2004.
- [3] Orriss, Gregory D. "Food fortification: Safety and legislation": Food and Nutrition Bulletin, 19:2. Tokyo: The United Nations University Press, 1998.
- [4] Wirakartakusumah, M. A., and Hariyadi P. "Technical aspects of food fortification": Food and Nutrition Bulletin. 19:2. Tokyo: The United Nations University Press, 1998.
- [5] Barclay, Denis. "Multiple fortification of beverages": Food and Nutrition Bulletin. 19:2. Tokyo: The United Nations University Press, 1998.
- [6] Killeit, U. "The stability of vitamins - a selection of current literature." Germany, Grenzach-Whylen: Hoffman-LaRoche AG, 1998.
- [7] Gibney, Michael J., Lanham-New, Susan A., Cassidy, Aedin, Vorster, Hester H., Introduction to human nutrition. Oxford: Wiley-Blackwell 2009.
- [8] Ottaway, P.B., "Stability of vitamins during food processing and storage", Chemical deterioration and physical instability of food and beverages. Woodhead Publishing Limited, 2010.
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