Food fortification has long been employed as a strategy to address demonstrated problems of nutrient insufficiency in populations. Although the specific regulatory mechanisms governing such fortification differ across jurisdictions, the guiding principles established by the Codex Alimentarius Commission have served as an international standard for the addition of essential nutrients to foods.
‘Discretionary fortification’ marks a significant departure from these principles. Sometimes termed ‘liberal’ or ‘voluntary’ fortification, it is the addition of vitamins and minerals at the discretion of food manufacturers for marketing purposes, but not as part of a planned public health intervention.
Discretionary fortification is therefore distinct from voluntary fortification programs implemented by public health authorities to address specific population health problems (such as the introduction of voluntary folate fortification in Australia and New Zealand in the 1990s as a strategy to reduce the risk of neural tube defects).
In countries such as the US, where most fortification is voluntary, discretionary fortification denotes nutrient additions that fall outside established standards of identity, nutrition quality guidelines, and other relevant regulations.
In countries like Canada, where nutrient additions aligned with Codex principles are tightly regulated, discretionary fortification simply describes fortification activity outside mandatory programmes. The nutrients added through discretionary fortification may correspond to nutrient needs in the population, but the defining feature of this fortification practice is that it occurs outside any defined public health strategy.
It is argued that discretionary fortification can provide consumers with a greater variety of sources for nutrients and thus help them to meet their requirements. However, concerns have been expressed that expanding fortification may function in opposition to the promotion of healthy eating, and that it may expose populations to risks of nutrient toxicity.
Fortification has been associated with intakes of some nutrients above tolerable upper intake levels (ULs). Whether such intake levels constitute serious threats to health is a subject of ongoing debate, but the findings highlight the potential for excessive intake in the context of uncontrolled additions of micronutrients to the food supply.
Regulators are therefore being challenged to determine safe levels of nutrient addition and establish procedures to monitor the effects of discretionary fortification on the population. As the practice of discretionary fortification unfolds, it is important to consider the public health implications of this phenomenon.
Improve Nutrient Intakes
The merits of nutrient additions to specific food products can be evaluated relative to the nutritional needs of target market groups, but assessing the population health impact of discretionary fortification as a policy direction requires analysis of the effects of this practice on usual nutrient intakes in the population.
The US presents a particularly fertile ground for studies of discretionary fortification because of its long history of manufacturer-driven fortification and extensive monitoring of dietary intakes.
On any day, about half of the population consumes some discretionarily fortified food, typically breakfast cereals or beverages. Drawing on data from the 2003–2006 National Health and Nutrition Examination Survey (NHANES), it was established that enrichment and fortification had a substantial effect on the prevalence of inadequacy for vitamin A, thiamin, iron, and folate among both children and adults.
Fortification and enrichment also contributed substantially to intake of niacin, riboflavin, and vitamins B6, B12, C, and D, but with less marked effects on nutrient adequacy.
For many B vitamins, the population prevalence of inadequacy was low even without added nutrients from fortification. For other nutrients such as calcium, magnesium, and vitamins C and E, fortification appeared insufficient to compensate for suboptimal dietary intakes.
Analyses of the contribution of fortified foods to usual nutrient intakes in other countries also indicate that their consumption diminishes the prevalence of inadequacies for some but not all nutrients, and some additions appear unnecessary.
These results highlight the haphazard nature of the effects of manufacturer-driven fortification; benefits only accrue when the nutrients added are not already attained in sufficient amounts from natural sources and when the scale of fortification is sufficient to shift otherwise inadequate intakes to adequate levels. Neither condition is assured when fortification occurs at the discretion of manufacturers.
Risks Of Excess
Analyses of the effects of fortification on the upper tails of estimated usual intake distributions suggest that in some instances, this practice may lead to nutrient exposures in excess of established ULs.
Among 2–18 year olds in the 2003–2006 US NHANES, small proportions of the estimated distributions of usual intake for vitamin A, niacin, and folate surpassed the ULs when nutrient intakes from fortification and enrichment were taken into account.
Even without considering fortification, 10 percent of children’s zinc intakes exceeded the UL, but this rose to 18 percent when fortified sources were included. When age groups were disaggregated further, 45 percent of 2–8 year olds were found to have usual zinc intakes (from natural and added sources) above the UL.
Inter-individual variation in nutrient exposure is commonly observed with mandatory fortification because of between-person differences in food selection and consumption patter ns, but the potential for such variation is magnified with discretionary fortification because by design, this practice expands the array of food choices by introducing options with greater nutrient density.
The ULs are the only available benchmark against which to appraise the safety of nutrient additions, but it is important to recognise their limitations.
Defined as the highest average daily intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population, the UL represents a ‘best estimate’ of a safe upper bound for a nutrient.
However, this is a nascent field in nutrition, and there is a paucity of data upon which to base determinations for many nutrients. Therefore, we have only crude estimates of safe upper ranges of intake for some nutrients, and no estimates whatsoever for others.
Several of the ULs that have been established differ across jurisdictions, reflecting different interpretations of the existing evidence. In many instances, the ULs established for children have been extrapolated from data on adults, raising questions about the validity of these estimates.
However, the most important limitation of the ULs with respect to their application to set policy on discretionary fortification is the fact that the ULs we have now were established to evaluate the safety of current intake levels, not the safety of future fortification. The health implications of long-term exposure to elevated doses of multiple vitamins and minerals from supplements and fortificants are unknown.
Influence On Dietary Patterns
Separate from questions about the safety of discretionarily fortified foods, there are concerns about the potential for this practice to promote or reinforce food consumption patterns that are deleterious to health.
Given that regulatory frameworks exclude staple foods from discretionary fortification (such as through standards of identity), the foods most likely to be targeted are processed foods with little intrinsic nutritional value.
The fortification of energy dense, nutrient-poor foods that are widely consumed can effectively increase nutrient intakes, for example, by the contribution of vitamin C-fortified fruit drinks to US children’s total intakes.
Whether the benefits associated with improved micronutrient intakes outweigh the risks associated with the macronutrient profile of the food vehicle is a matter of debate, as is the question of whether the fortification of foods with undesirable nutritional attributes such as added sugar functions to foster greater consumption of such products.
However, the case of fortified fruit drinks highlights the tension between discretionary fortification practices and public health strategies designed to dietary practices that support healthy body weights and lessen risks of diet-related chronic diseases.
With foods high in added sugars now targeted for reduction in an effort to combat rising rates of obesity, public health measures that limit the consumption of sugar-sweetened fruit drinks in the US could adversely affect children’s micronutrient intakes.
Setting Safety Standards
As discretionary fortification practices expand, recognition of the potential risks of uncontrolled nutrient additions to the food supply is driving the development of safety standards.
These may include prohibiting the addition of some nutrients (such as retinol) or delineating the nutrients allowed to be added at the discretion of manufacturers and setting limits on the amounts of particular nutrients that can be added per 100 kcal or portion of food.
The myriad of assumptions and data limitations underpinning the estimation procedures being used to develop safety standards begs the question of how well regulators will be able to manage the potential risks associated with expanding discretionary fortification.
The benchmarks being applied to define upper safe levels of intake derive from very crude estimation procedures, in many cases with very limited data on toxicity; the resulting estimates are not necessarily indicative of safety in relation to the chronically high nutrient exposures that will result from expanded fortification and continued supplement use.
The manufacturing practice of overage means that nutrient levels in foods consumed may be higher than those listed in food composition databases. Furthermore, discretionarily fortified foods are not well captured in existing food composition databases and dietary intake surveys, because this is such a rapidly evolving practice.
Errors in the assessment of nutrient intakes from fortified foods have serious implications for safety calculations premised on filling the ‘free space’ because fortified food consumers sit at the upper tails of population intake distributions; underestimation of their intakes means an overestimation of the potential for expanded fortification.
Managing Exposure Through Labelling
In addition to restricting nutrient additions, regulator y bodies can influence food manufacturing practices with respect to fortification through the implementation of labelling regulations that function as marketing incentives and disincentives.
In the US, for example, voluntary food fortification has been managed in part through the regulation of nutrient content claims that are tied to specific compositional criteria.
It is assumed that manufacturers will fortify products to the levels required to enable them to make specific nutrient content claims ( such as ‘product X is good/ excellent source of nutrient Y’), but there will be no marketing advantage to nutrient additions beyond the thresholds for these claims.
The extent to which voluntary fortification practices are intertwined with nutrition labelling regulations in the US is evident in the public health concerns spawned by plans to update the Daily Values used in nutrition labelling (a reference standard based on recommended nutrient intakes) to reflect more current science.
If lower Daily Values are set for some nutrients, this could result in lower nutrient additions to widely consumed products because manufacturers need to add less to qualify for nutrient content claims, with potentially deleterious effects on nutrient adequacy in the population.
Further evidence of the dynamic relationship between regulated labelling and product formulation in the US can be found in the Institute of Medicine’s recent decision to not include an assessment of micronutrients in its recommendation for standardised front-of-package nutrition labelling, so as not to encourage more voluntary food fortification and increase the risk of excessive nutrient intakes.
As discretionary fortification expands, food manufacturers appear to be seizing opportunities for product innovation and taking new approaches to food marketing. While our examination of novel beverages was very limited in scale, the on-package marketing of these products was noteworthy. The presence of specific nutrients was typically indicated on the front-of-package, but most manufacturers eschewed regulated nutrient content claims, diet-related health claims, or other conventional nutrition references. This occurred even though the levels of nutrient addition far exceeded thresholds required to make such claims.
Diego Sevilla Ruiz
The development of regulations based on the principle of filling the ‘free space’ without exceeding the upper bounds of safe intakes denoted by the current ULs could conceivably protect populations from excessive nutrient exposures, assuming estimates of exposure were accurate and the science underpinning whatever ULs were applied was sound and relevant to emerging fortification scenarios.
Even with these caveats though, it is important to recognise that such regulatory action does not imply, let alone ensure, that discretionarily fortified foods will confer any benefit to those who purchase them.
The task of discerning benefit in the context of market-driven food fortification is left entirely to the consumer. This extraordinarily difficult task is ill-supported by the nutrition information currently provided to consumers.
While the labels of discretionarily fortified foods may include nutrition and health claims, such text appears at the discretion of the manufacturer and it is part of product marketing.
The only mandatory, standardised nutrition information on product labels in most jurisdictions is a Nutrition Facts table. The table provides information on the nutrient contribution of one serving for selected nutrients, expressed as a percentage of the Daily Value. Yet, it is not uncommon for novel beverages to report nutrient levels that are several hundred percent of the Daily Value.
The Nutrition Facts table communicates nothing about the probability that a consumer stands to benefit, or could be placed at risk, from the nutrients listed. An extraordinarily high level of nutrition knowledge is required for a consumer to understand that he already has a very high probability of meeting his riboflavin or niacin requirement, for example, and therefore is unlikely to benefit from consuming a beverage offering 500 percent of the Daily Value for that nutrient.
Consumers cannot possibly differentiate between nutrients added that would help them to meet their requirements and nutrient additions that are simply about manufacturers filling the ‘free space’. Nutrition education programs could perhaps be developed to help consumers evaluate the potential risks and benefits of specific discretionarily-added nutrients, but this would necessitate training people to micro-manage their micronutrient loads.
Discretionary fortification represents a marked departure from food fortification designed to address public health needs. The potential for health benefits from manufacturer-driven fortification appears to be remote, given how common it now is for manufacturers to add nutrients with no evidence of need.
Unfortunately, we are ill-equipped to appraise the risks of permitting expanded food fortification for marketing purposes. While there is a strong foundation of nutritional science upon which to determine the benefits (or lack thereof) of discretionary nutrient additions, the long-term health implications of chronic exposure to the high nutrient loads achievable through expanding fortification and supplement use are largely unknown.
Therefore, the risks of discretionary fortification remain to be discovered. With regulators attempting to manage the safety of rapidly evolving fortification practices through crude estimates of the ‘free space’ left to be filled with nutrient additions, while leaving consumers to discriminate between possibly beneficial fortification and gratuitous nutrient additions, discretionary fortification is a policy direction in need of serious review.