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6
Framework for the Development of
Policy Options to Reduce Exposure to
Dioxins and Dioxin-like Compounds
A central element of the committee's charge was to identify, evaluate, and
recommend policy options for reducing human exposure through diet to dioxin
and dioxin-like compounds (referred to collectively as DLCs). In considering
DLC exposure reduction options, the committee was charged with taking into
account both possible reductions in human health risk associated with reducing
DLC intake and the possible nutritional consequences of dietary changes that
might result from the selected measures. In response to this charge, the commit-
tee has identified a number of possible exposure reduction (or risk-management)
options, which are described in Chapter 7; in Chapter 8, the committee makes
risk-management recommendations.
One of the committee's primary conclusions, however, is that the data re-
quired to evaluate and recommend a comprehensive set of risk-management
interventions for DLCs are lacking. There remains substantial uncertainty about
the magnitude of the risks posed by low levels of dietary exposure to DLCs and
corresponding uncertainty about the magnitude of the risk reductions that are
achievable by reducing such exposures. This uncertainty will be a substantial
limiting factor for the government as it considers risk-management strategies,
especially to the extent it considers the use of its traditional food safety regulatory
tools, as discussed below. The study's sponsors, however, asked the committee
not to evaluate or repeat the extensive risk assessment work that has been done on
DLCs (see AEA Technology, 1999; ATSDR, 1998; EPA, 2000; Fiedler et al.,
2000; IARC, 1997; and Scientific Committee on Food, 2000, 2001~. In keeping
with its charge, the committee has proceeded with its identification of risk-man-
agement options on the premise that reductions in DLC exposure are desirable for
150
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
151
health reasons in light of: (1) the extensive animal data demonstrating the toxicity
of DLCs at very low exposure levels, (2) the cumulative effect even low levels of
exposure can have on an individual's total DLC body burden, and (3) the exist-
ence of vulnerable subpopulations, such as fetuses and breastfeeding infants and
individuals (e.g., subsistence fishers) whose traditional diets, for cultural or eco-
nomic reasons, may result in higher levels of DLC exposure.
Even with the assumption that reducing dietary exposure to DLCs is desir-
able, insufficient data are available to assess and support at least some of the
potential risk-management options for DLCs. For example, the data on DLCs in
the food supply, including the incidence, levels, and geographical distribution of
DLC contamination in various animal production systems and in raw, processed,
and cooked foods, are extremely limited, as discussed in Chapters 4 and 5. Such
data would be required to most effectively target and prioritize risk-management
interventions and support the establishment of regulatory limits on DLCs in food,
if the government considered that an appropriate option for reducing DLC expo-
sure. The committee also found very little data that would help to assess the
feasibility and calculate the costs and other impacts of the wide range of risk-
management options that are potentially available to reduce DLC exposure
through the food supply. This paucity of data is particularly evident in the animal
production arena, where the ecology and epidemiology of these compounds un-
der normal production conditions are not available. Further examples of data
limitations that affect the consideration of risk-management options are provided
later in this chapter and in Chapter 7.
Because of the large gaps in the data required to devise an optimal, compre-
hensive risk-management strategy for DLCs and to assess specific options, the
committee was unable to reach conclusions on the likely effectiveness of a num-
ber of the possible risk-management options it identified, or on a relative ranking
of these options. It thus focused its efforts on devising a framework for the
development and evaluation of options for reducing DLC exposure. The pro-
posed framework is described in this chapter.
The purpose of the framework is to provide a systematic basis to identify
risk-management options and to collect and analyze the data required to evaluate
the options. As discussed below, the framework divides the universe of options
into three categories: (1) options to reduce DLCs in animal forage and feeds, (2)
options to reduce DLCs in the human food supply, and (3) options to change
food-consumption patterns to reduce DLC exposure. The framework is suitable
for evaluating a wide array of risk-management options, including regulatory
interventions, voluntary and collaborative interventions, and nonregulatory in-
centives. In identifying possible options, the committee assumed that the govern-
ment would be operating within current statutory authorities; the key food safety
statutory provisions and other legal tools applicable to DLCs are thus summa-
rized in this chapter.
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
Finally, the framework addresses the committee's charge to consider the
possible nutritional consequences of dietary changes that might occur as a result
of measures taken to reduce exposure to DLCs. The committee recommends for
this purpose an approach called "risk-relationship analysis," which takes a com-
prehensive approach to assessing how measures taken to prevent or mitigate a
particular risk can affect other risks to individuals or populations, whether by
causing a countervailing increase in risk or by causing ancillary risk reductions.
This chapter concludes with a discussion of risk-relationship analysis and how it
applies to the evaluation of risk-management options for DLCs.
CATEGORIZING POSSIBLE RISK-MANAGEMENT OPTIONS
In developing an inventory of possible risk-management options to reduce
exposure to DLCs, the committee concluded that opportunities to reduce dietary
exposure fall into three major categories, which correspond to the three distinct
stages of food production, processing, and consumption within the farm-retail
chain. The committee's framework organizes the possible options into these three
categories, each of which has its own distinct attributes and its own features that
affect the feasibility and effectiveness of possible interventions.
Animal Production Systems
As discussed in Chapter 4, the forage and feeds consumed by food-produc-
ing animals, including fish, is one of the most critical pathways for the entry of
DLCs into human food and for human exposure to these compounds. It is also the
most promising pathway that provides an opportunity to interdict and reduce
DLC contamination of the human food supply.
One major source of DLC contamination is air deposition of DLCs onto
plants that are used for forage and feeds. When animals consume plants, their by-
products, sediment-contaminated waters, or soils directly, DLCs are ingested and
stored in the animals' fat. When humans consume the animals' fat as part of their
diets, they are exposed to DLCs.
The importance of animal feeds as sources of DLCs in human diets is en-
hanced by the practice at abattoirs of rendering fats and animal proteins from
fallen (recently dead) animals and offal not acceptable for human consumption,
and using the salvaged fat in animal feeds, which is then distributed nationally in
the animal feed system. This practice has the effect of recycling and potentially
concentrating the DLCs that are present in animal fat because of environmental
exposures, and of increasing DLC exposure to humans through the food supply.
Interrupting this cycle of DLC contamination of the food supply via the animal
feed pathway is, in the committee's judgment, a high-priority risk-management
option.
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
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The advantage of forage and feeds as a focal point for measures to reduce
DLC exposure is that steps taken at this stage can prevent DLCs from entering
human food. Such steps include limiting access to forage in areas known to be
high in DLC contamination and limiting the use of recycled animal fat in animal
feeds or setting direct limits on the levels of DLCs permitted in animal feeds.
Measures of this kind impose costs (e.g., loss of use of land for grazing in highly
contaminated areas, increased production costs) and may have other consequences
that the committee believes should be considered under the proposed framework.
However, any reductions in DLC contamination that are achieved at the forage
and feed stage have the important benefit of directly reducing the reservoir of
DLCs in food to which humans are potentially exposed.
Human Food
The second major category of opportunities to reduce DLC exposure identi-
fied by the committee involves reducing DLC levels in the foods people con-
sume. Once DLCs are present in human food or in the fat of food-producing
animals, risk-management options are available, but they may be more limited in
their potential to reduce DLC exposure than interventions at the forage and feed
stage. In some cases, such as when DLCs are present on the exterior surfaces of
fruits and vegetables through direct airborne deposition onto leaves or the pres-
ence of DLC-contaminated soil that clings to peels, washing leafy surfaces or
removing the outer peels from produce can reduce DLC exposure. DLCs can also
be reduced in human food by trimming excess fat from cuts of meat or otherwise
reducing the amount of animal fat in food. At present, processing methods to
directly remove DLCs from animal foods do not exist.
When the removal or reduction of DLCs through washing or other process-
ing interventions is not possible, reduction of DLC exposure at the human-food
stage can be achieved by limiting the levels of DLCs permitted in the foods. This
would require removing foods from the food supply if they contain DLCs above
some permissible level. Because human foods or food components generally
have greater economic value than animal feeds or feed components, the cost
issues that would have to be considered under the food safety laws or in the
committee' s analytical framework could be greater. However, this would depend
on a wide range of cost factors associated with intervention strategies at different
points in the farm-retail supply chain.
Food-Consumption Patterns
Finally, the committee identified changes in individual food-consumption
patterns as a vehicle for reducing DLC exposure. This involves reducing the
consumption of foods or food components known or expected to be high in DLCs
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
and substituting foods that are likely to be lower in DLCs. Because individual
food-consumption patterns are generally beyond direct regulatory control, the
risk-management options in this category are likely to involve education, expan-
sion of food choices, incentives, and other interventions to encourage voluntary
changes in what people eat.
The options for reducing DLC exposure through changes in food-consump-
tion patterns are likely to vary in their feasibility and effectiveness depending on
the circumstances of the individual. For example, changing consumption patterns
may be very difficult for indigenous populations highly dependent on wild-caught
fish and other game from areas with high environmental contamination levels. It
may be relatively easy for school-age children who can reduce DLC intake by
replacing whole milk with low-fat (1 percent milk fat) or skim milk. The health
benefit of changing consumption patterns to reduce DLC exposure may also vary
considerably depending on age and other factors. For example, adolescent girls
and their future offspring might benefit substantially by reducing the animal fat
content of their diets and thus their DLC intake, while the benefits for adults may
not be as great. These factors should be considered in designing risk-management
interventions and analyzing them in the committee's proposed framework.
THE RANGE OF POSSIBLE RISK-MANAGEMENT OPTIONS
As suggested by the preceding discussion and presented in more detail in
Chapter 7, there is a wide range of possible risk-management options for reduc-
ing DLC exposure from food. The range is defined not only by the three catego-
ries or stages in the food chain that are outlined above, but also by the type of
intervention. These include: (1) the use of traditional food safety regulatory tools,
(2) collaborative and voluntary interventions involving food safety agencies and
the food industry, (3) public policy and regulatory interventions beyond tradi-
tional food safety interventions, including subsidies, economic incentives, and
other measures to reduce DLCs and expand dietary options, and (4) information
and education interventions. All of these have been considered by the committee
in identifying possible risk-management options, and they are addressed by the
committee's proposed framework.
Traditional Food Safety Regulatory Tools
The most common risk-management intervention by the federal government
with respect to food contaminants such as DLCs is the enforcement of the food
adulteration provisions in the Federal Food, Drug, and Cosmetic Act (FDCA) of
1938 and other federal food safety laws that deal specifically with meat and
poultry. Jurisdiction over food safety is shared between the U.S. Food and Drug
Administration (FDA), the U.S. Department of Agriculture (USDA), and the U.S.
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
155
Environmental Protection Agency (EPA). As discussed in more detail below,
current laws prohibit the presence in food of substances that are potentially
harmful to health, and they authorize FDA to act to prevent contamination of the
food supply with such substances, either by setting and enforcing standards for
the amount of such substances that can be present, or by bringing case-by-case
enforcement actions against the products that the government believes are con-
taminated at harmful or potentially harmful levels. FDA has used these tools to
restrict the presence of mercury, lead, aflatoxin, and other naturally occurring and
man-made contaminants in foods. The central theme of these and other tradi-
tional food safety regulatory tools is that they involve the use of the government's
legal powers to prohibit harmful contamination or practices that could result in
such contamination.
Collaborative and Voluntary Interventions
As an alternative to mandatory regulatory interventions, the food safety agen-
cies have the option to initiate collaborative programs with the food industry
dependent on the willingness of the industry to act voluntarily to reduce a hazard.
FDA could, for example, work with animal producers to develop guidance or
voluntary codes of practice that producers could follow to reduce DLCs in animal
forage or feeds, or the government could provide technical or other support for
industry-sponsored DLC testing programs. Such collaborative and voluntary
measures assume that the industry has its own interest or incentive for taking
action to reduce DLC levels in foods. In such cases, they may be viable risk-
management options, especially if the data required to support the use of tradi-
tional regulatory tools are unavailable.
Subsidies, Economic Incentives, and Other Measures
to Reduce DLCs and Expand Dietary Options
Beyond the traditional regulatory or cooperative approaches to reducing
DLCs, there are a number of other tools of public policy that, though rarely used
to address food safety hazards, are at least theoretically available to the govern-
ment to foster reductions of DLCs. These could include, for example, subsidies or
other economic incentives, such as taxes, to induce reductions in the use of
animal fat in animal feeds; development of alternative uses for animal fats other
than feeds (e.g., biofuels); or the reduction of the fat content of processed foods.
The government could also act to expand the information and choices available to
consumers who might want to reduce animal fat in their diets, such as by expand-
ing nutrition labeling of meat or mandating the availability of low-fat or skim
milk in school lunch and other government feeding programs.
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
Information and Education Interventions
The final category of possible risk-management interventions is aimed pri-
marily at consumers and involves the use of information and educational cam-
paigns to encourage the changes in dietary patterns that would be expected to
reduce DLC exposure. Such campaigns might be aimed at indigenous popula-
tions whose traditional diets are drawn from contaminated areas, or at main-
stream consumers who might achieve reductions in DLC exposure by conform-
ing their diets to the government's Dietary Guidelines or to the Food Guide
Pyramid.
LEGAL FRAMEWORK FOR THE
IMPLEMENTATION OF INTERVENTIONS
As noted earlier, the committee assumed for purposes of identifying and
analyzing risk-management options that the government would continue to oper-
ate under current statutes, although legislation to address a particular hazard is
always possible. The following summary focuses on these options because they
traditionally have been the primary means through which the government has
acted to reduce dietary intakes of environmental contaminants such as DLCs.
There are, however, constraints in the form of substantive standards and burdens
of proof that have an important effect on what the government can do to address
a particular hazard. These constraints are among the reasons the committee has
considered a range of nonregulatory, as well as regulatory, options for reducing
dietary intakes of DLCs.
Food Safety Regulatory Tools
Among the regulatory agencies in the federal government, FDA has the
primary food safety regulatory jurisdiction over DLCs in animal feeds and human
food categories other than meat and poultry. For meat and poultry, USDA's Food
Safety and Inspection Service (FSIS) plays the enforcement role. FDA is the
federal government's food safety standard-setting agency for environmental con-
taminants, other than pesticides. EPA considers food safety and acceptable levels
of DLCs in fish by setting acceptable air and water emission levels for DLCs.
The FDCA provides FDA with the broad authority to control or prohibit the
presence in food of contaminants such as DLCs. The authority is broad in the
sense that FDA can act to control DLCs in both animal feeds and human food;
can intervene at virtually any stage of food production, processing, and market-
ing; can set mandatory standards applicable to broad categories of DLC-contain-
ing feeds and foods; and can take case-by-case enforcement action to remove
DLC-contaminated food from commerce. FDA's authority is constrained, how-
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
157
ever, by the fact that its exercise is conditioned on the agency being able to make
certain factual showings concerning DLCs and the risks they pose.
Statutory Adulteration Provisions
FSIS has similar adulteration authorities for meat and poultry. Under the
Poultry Products Inspection Act and the Federal Meat Inspection Act, FSIS may
take action against meat or poultry that contains an added poisonous or deleteri-
ous substance that may render the product injurious to health. Also, FSIS has
authority to act against a product that is for any reason unhealthful, and against
product that has been prepared under insanitary conditions whereby it may have
been rendered injurious to health.
Under these provisions, DLCs generally would qualify as poisonous or del-
eterious substances. The "may render" adulteration standard has been interpreted
by the courts to mean that there must be a "reasonable possibility" that the
substance will cause harm at the levels at which it is present in food. This stan-
dard does not require proof of actual harm to health, but it does require scientific
evidence demonstrating that there is a reasonable possibility of harm to at least
some who consume the food. Likewise, the adulteration provision that deems
added but avoidable poisonous or deleterious substances to be adulterants re-
quires factual evidence that the particular level of the substance in food is avoid-
able using GMPs. The practical meaning of this avoidability standard of adultera-
tion has not been clearly defined by FDA or the courts. As persistent and pervasive
environmental contaminants, DLCs would likely be considered unavoidable at
some low concentration, but determining the line between avoidability and un-
avoidability for DLCs poses complex factual and policy issues, and that line has
not been drawn.
To enforce the first two adulteration provisions noted above, FDA could
choose to proceed on the basis of case-by-case enforcement action, through infor-
mal or formal standard-setting, or a combination of these two. FDA has the
option, if it can prove that a particular lot of food contains an environmental
contaminant at a level that violates one of the adulteration provisions, to seek
court action to remove that lot from commerce and prevent its future distribution.
This can be done without any prior notice or setting of standards concerning the
level of the contaminant the agency considers to be in violation of one of the
adulteration provisions. FDA rarely proceeds on this basis, and it would be an
inefficient way to address a pervasive environmental contaminant such as DLCs.
FSIS has the authority to withhold the mark of inspection from product,
which is necessary for the product to enter commerce, if it is not able to find that
the product is not adulterated. Once the product is in commerce, FSIS' s authority
is similar to FDA's.
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Action Levels
DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
Instead, prior to taking court enforcement action, FDA typically announces
in advance the level of an environmental contaminant against which it is prepared
to act. FDA calls these levels action levels. They are not regulations and do not
have any binding legal effect on FDA or on private parties. Technically, they are
guidelines for use by FDA enforcement officials in deciding when to bring court
enforcement action against a contaminated food or its purveyor under one of the
adulteration provisions. In such an enforcement action, FDA still has to prove to
a court's satisfaction that an adulteration provision has been violated. As a prac-
tical matter, however, FDA' s action levels operate as guidance to the food indus-
try and are recognized by many food producers and processors as informal stan-
dards with which they seek to comply. To date, FDA has not set action levels for
DLCs as a class, though it has established an action level for polychlorinated
biphenyls (PCBs) in meat.
Tolerances
In the case of added substances that are at least to some extent unavoidably
present in food, as in the case of environmental contaminants like DLCs, FDA
has statutory authority to establish binding legal limits on the level of the sub-
stance that may lawfully be present in food. These limits are called tolerances.
They are set at the level FDA considers necessary to protect public health, taking
into account the extent to which the presence of the substance in food is unavoid-
able. Tolerances are regulations that the FDCA requires be established under
"formal" rulemaking procedures, which involve public notice and comment and
formal trial-like hearings. These rulemaking procedures are costly and time con-
suming. The advantage of tolerances, from an enforcement perspective, is that
they are legally binding and directly enforceable through court action without any
further showing by FDA that the food is unsafe or adulterated. The only toler-
ances FDA has established to date are for PCBs in certain human foods (milk,
dairy products, poultry, eggs, fish, infant and junior foods) and in animal feeds
and feed components for food-producing animals.
Regulatory Limits
Due to the cumbersomeness of the formal rulemaking procedures required to
establish tolerances, FDA has created an "informal" rulemaking process for es-
tablishing regulatory limits for added poisonous or deleterious substances. A1-
though FDA has yet to use this procedure to establish any regulatory limits, it is
available in cases in which FDA is not prepared to establish a tolerance (because,
for example, the levels of a contaminant may be in flux), but is prepared to define
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
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the level at which it deems the contaminant to adulterate food because it "may
render [the food] injurious to health" (Merrill and Schewel, 1980~. Regulatory
limits would be established following public notice and comment, but without the
formal hearings required for tolerances. It is uncertain how much deference courts
would accord FDA's regulatory limits in an enforcement case.
Good Manufacturing Practices
The provision that declares food to be adulterated based on the conditions
under which it has been prepared has been used by FDA to promulgate regula-
tions establishing GMPs and other requirements for food production that are
intended to prevent potentially harmful contamination. FDA has established GMP
regulations for animal feeds and human food, but these currently address general
practices for safe and sanitary food production; they do not establish any stan-
dards or requirements for preventing or minimizing contamination with specific
contaminants such as DLCs. FDA could attempt to use its GMP authority for this
purpose, but the agency would have to support such regulations with evidence
that establishes a link between any specific GMPs for DLCs and the prevention of
situations in which the food may be injurious to health. This evidence would be
difficult to provide given the lack of data on these linkages.
Practical Constraints on Regulatory Options
While FDA has successfully used these regulatory tools to address a wide
range of food safety issues, including hazards posed by environmental contami-
nants such as lead, mercury, and aflatoxin, the agency would face significant
practical constraints in applying them to DLCs in feeds and food. As discussed in
Chapter 2, there continues to be scientific debate and uncertainty about the level
of human intake of DLCs required to cause adverse health effects in the popula-
tion at large and in specific subpopulations, especially in light of the fact that the
risks of DLCs are generally thought to be associated with their accumulation in
human tissue over time. This uncertainty does not necessarily preclude, but would
certainly complicate, any effort by FDA to establish tolerances or other regula-
tory standards through rulemaking or to enforce adulteration provisions through
court proceedings. In such rulemaking and court enforcement proceedings, FDA
would bear the burden of proving the potential of DLCs to cause harm to human
health at relatively low intake levels.
In addition, effective compliance monitoring and enforcing regulatory stan-
dards both require the availability of practical analytical methods and a credible
level of testing to detect violations. The expense of available testing methods
creates a barrier to enforcing regulatory standards for DLCs. The difficulty of
meeting this legal burden, in light of the uncertainty about risk at low exposure
levels and the paucity of data on actual levels of DLCs in food, is one of the
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
reasons the committee is not recommending any immediate action using these
traditional food safety regulatory tools. The committee is aware of the recent
initiative of the European Union (KU) to establish quantitative standards for
DLCs in feeds and food, as discussed in Chapter 2, but notes that EU regulatory
policymakers are not subject to the same legal constraints as U.S. regulators
since, in the EU system of government, the adoption of the DLC policy was itself
a legislative act.
Voluntary Guidance, Cooperative Programs, and
Subsidies to Reduce DLCs
Regulatory agencies, including FDA and FSIS, commonly supplement their
regulatory standard setting and enforcement programs with collaborative pro-
grams to encourage and support voluntary efforts by food producers and proces-
sors to address health, safety, and environmental problems. Such efforts can be
productive when private entities are provided incentives to address issues when
regulatory mandates are absent, and they are often pursued in circumstances in
which there are legal, scientific, resource, or other practical constraints that make
regulatory intervention difficult or impracticable. For example, both FDA and
FSIS have begun to work with food producers to foster voluntary good agricul-
tural practices (GAPs) and other measures at the food production level to address
food safety hazards posed by microbial pathogens.
The committee has identified a number of voluntary efforts as options to
reduce DLC levels in feeds and food. They include setting nonbinding targets for
reducing DLC levels in feeds and food, working with the industry to establish and
encourage the adoption of voluntary GAPs and GMPs, and providing data on the
current levels and sources of DLCs in feeds and food to support voluntary reduc-
tion efforts. There are no legal constraints on such efforts.
The committee has also identified various economic subsidies to food pro-
ducers and processors as possible options for reducing DLC levels in feeds and
food. These options may be more novel as a policy matter and require additional
resources that are not provided for in the budgets of the food safety regulatory
agencies. In addition, the regulatory agencies likely lack legal authority for such
subsidies. These options would thus require congressional action to implement.
Reducing Dioxin Intake by Changing Food-Consumption Patterns
Perhaps the most direct way for an individual or a population to reduce
dietary intake of DLCs is to reduce their consumption of dietary fat, especially
from animal sources that are known to contain higher levels of these compounds.
The federal government has little or no legal authority to directly control what
people eat, but the committee has identified a number of options to encourage
changes in food-consumption patterns that, if achieved, would reduce dietary
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163
interventions that are being considered to reduce a target risk could plausibly
increase some other health risk. Consideration of such countervailing risks is
sometimes called risk-risk or risk-tradeoff analysis. In the case of DLCs in food,
however, the committee considered it at least equally plausible that dietary
changes to reduce DLC exposure could have ancillary health benefits, in addition
to whatever health benefit was achieved by reducing DLC intake. In particular,
reductions in the consumption of animal fat to reduce DLC exposure may also be
associated with a number of other health benefits, including reductions in cardio-
vascular disease and cancer. The committee thus decided to adopt a framework
for analysis of DLC risk-management options that is broader than a risk-risk or
risk-tradeoff framework. It involves risk-relationship analysis.
In the context of diet-related issues, risk-relationship analysis recognizes that
most human foods provide a combination of desirable and undesirable compo-
nents. In addition to attractive taste, texture, and other aesthetic attributes, desir-
able components include macronutrients (protein, carbohydrate, certain fats, and
fiber) and micronutrients (vitamins and minerals) that are required to support
health and maintain adequate nutritional status. Other food components that may
be undesirable and pose health concerns for consumers include excess levels of
saturated fats and cholesterol and both naturally occurring and man-made food-
borne toxins. Components that should not be present in foods include microbial
pathogens, pesticides, and other hazardous contaminants. At a fundamental level,
optimizing dietary choice can be viewed as choosing a mixture of foods that
provides adequate and balanced qualities of desirable components, while mini-
mizing health risks associated with the consumption of undesirable components
or contaminants.
Defining a "healthy diet" remains a matter of controversy, precisely because
food is compositionally so complex, dietary patterns are so varied, and there
remains considerable scientific uncertainty about the interactions of dietary com-
ponents and the impact of changes in dietary patterns. Nevertheless, the U.S.
Dietary Guidelines for Americans (USDA/HHS, 2000), which establishes the
policy, and the Food Guide Pyramid (USDA, 1996), which provides the educa-
tional component, reflect consensus recommendations about desirable intakes of
micro- and macronutrients. The committee concludes that, in considering risk-
management options to reduce DLC exposure, it is appropriate to conduct a risk-
relationship analysis that considers whether a proposed intervention would affect
dietary patterns, for better or worse, in relation to current dietary guidelines.
Ideally, a risk-relationship analysis would provide a quantitative basis for
considering and comparing the risk reduction likely to be achieved by the pro-
posed intervention, any countervailing health risks the intervention might cause,
and any expected ancillary health benefits (see Box 6-1~. Proposed interventions
that have positive net health impacts, based on an aggregation of such quantita-
tive assessments, would be candidates for consideration, subject to whatever
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
legal standards and other impact assessments that might be relevant to the selec-
tion and implementation of a risk-management option.
As is made clear in the discussion of specific risk-management options in
Chapter 7, it may not be possible to conduct quantitative risk-relationship analy-
ses, and even the qualitative outcome (i.e., are net health benefits likely to be
positive or negative) of a risk-management option may be unclear. This is the
case for several reasons: (1) the models and data required to predict changes in
dietary patterns are extremely limited, (2) a given intervention might push diets in
more than one direction; for example, reductions in the consumption of full-fat
dairy products could not only reduce overall intake of undesirable animal fat, but
it could also reduce the overall intake of desirable calcium if the low-fat product
is not consumed, and (3) the health consequences of a given dietary change will
vary among demographic groups (e.g., by age and sex) and among individuals
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(depending on the individual's health status and the nature of the diet prior to the
intervention).
Despite these complexities and uncertainties, which inevitably make the
answers produced by risk-relationship analysis uncertain, questions about coun-
tervailing health risks and ancillary health benefits are worth asking. In at least
some cases, they can help affirm a proposed course of action or point policy-
makers in a different direction than originally proposed.
OVERVIEW OF THE PROPOSED FRAMEWORK
With the foregoing considerations in mind, the committee adopted a frame-
work for identifying and analyzing risk-management options for reducing DLC
exposure. In Chapter 7, these options are presented in three matrices correspond-
ing to the three major categories of intervention options:
Matrix 1: Intervention Options Considered to Reduce DLC Exposure
Through Pathway I: Animal Production Systems
Matrix 2: Intervention Options Considered to Reduce DLC Exposure
Through Pathway II: Human Foods
Matrix 3: Intervention Options Considered to Reduce DLC Exposure
Through Pathway III: Food-Consumption Patterns
Within these matrices, each considered option is presented in the format shown in
Figure 6-1. This format captures the series of questions the committee believes
government agencies should consider in identifying and analyzing risk-manage-
Option
Alternate/l nterim
Actions
Current Barriers
to
Implementation
DLC Exposure
Reduction
Exposure Reduction:
Risk-
Relationship
Analysis
Ancillary Benefits:
Countervailing Risks:
FIGURE 6-1 Format for analyzing intervention options considered to reduce DLC
exposure.
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
ment options for DLCs in food: (1) possible alternate or interim actions that could
be taken in the short term if the proposed intervention is not immediately feasible,
(2) the current barriers to implementation of a proposed option and its practical
feasibility, (3) the potential target DLC exposure reduction achievable through
the proposed intervention, and (4) the existence and size of ancillary benefits and
countervailing risks associated with the option.
The proposed framework and matrices respond directly to the committee's
charge to consider options for reducing DLC exposure, taking into account the
possible nutritional consequences of dietary changes that might result as a conse-
quence of the measures taken. The charge to the committee and the proposed
framework address the health consequences of efforts to reduce DLC exposure,
not the economic consequences. The committee considers the practical feasibility
of a proposed intervention to be a valid threshold question because no health
benefit will accrue from an intervention that cannot feasibly be implemented.
While the committee considers the economic feasibility of the options to be a key
issue, it has not included benefit-cost analyses of the specific options proposed in
the framework. This is primarily because consideration of the economic costs of
DLC reduction options is beyond the scope of the committee's charge, except to
the extent that economic costs imposed by an intervention affect dietary patterns
and health. In addition, the traditional food safety regulatory tools do not provide
for the consideration of benefit-cost analyses in setting food safety standards.
Nevertheless, the committee recognizes that major government regulatory
decisions, even if not controlled by cost-effectiveness, benefit-cost, or other eco-
nomic analyses under their authorizing legislation, are subject to regulatory im-
pact assessments under presidential Executive Orders administered by the Office
of Management and Budget in the Executive Office of the President. Moreover,
such economic analyses are likely to play a role in decisions on whether to mount
significant new initiatives to reduce DLCs. These analyses raise their own com-
plicated issues, from both methodological and policy perspectives, and these
issues are beyond the scope of this report.
The elements included in the committee's proposed analytical framework
are described in more detail in the following sections.
Alternate or Interim Actions
Closely related to the issue of feasibility is the need to consider, for each
proposed intervention, whether there are alternate or interim actions that could be
taken in the short term to begin making progress in reducing DLCs or to make
necessary preparations for interventions that may not be feasible at present. The
committee finds that, while substantial public investments have been made to
collect the information required for risk assessment with respect to DLCs (e.g.,
toxicity and epidemiological and exposure data), relatively little public invest-
ment has been made to collect the data and develop the tools required for risk
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
167
management, such as rapid and inexpensive test methods. For example, there are
very limited data on the actual distribution of DLCs in the production chain and
food supply at the level of detail required to establish binding regulatory limits on
DLCs in feeds or food, or for mandating significant changes in current production
practices that affect the presence of DLCs in food. Thus, it is appropriate with
respect to a number of the proposed interventions discussed in Chapter 7 to
consider alternate or interim steps, such as developing improved test methods,
expanding data collection programs, and fostering voluntary efforts to reduce
DLCs.
Current Barriers to Implementation
The committee considered at length how DLCs enter the food supply, their
pervasiveness, and some of the obstacles to reducing DLC exposure from food.
No one desires the presence of DLCs or directly controls their entry into the food
chain. DLC contamination is, for many participants in the food chain, an un-
avoidable phenomenon. The widespread presence of DLCs in the environment
means that DLC contamination is, to some extent, embedded in the way food is
produced, beginning on the farm or in waterways. This is why, in the committee's
view, continued efforts to reduce environmental emissions must remain a key
element of any DLC exposure reduction strategy.
The fact of widespread DLC contamination of the environment does not
mean there are no feasible interventions to reduce DLC exposure through food.
The committee has identified, and discusses in Chapter 7, a number of risk-
management options that are more or less feasible, depending on the point in the
food chain at which the option seeks to reduce DLCs and on the magnitude of the
reduction being sought. Some options are clearly feasible technically, such as
replacing the animal fat with high DLC levels that is contained in animal feeds
with other energy sources, but they may require such significant change in cur-
rent practices or may raise other issues (such as finding alternative means to use
or dispose of the fat) that their practical feasibility may be legitimately ques-
tioned. Other options may simply not be technically feasible, at least at present,
such as the removal of DLCs from feeds or food components through processing.
In any event, technical feasibility is an appropriate first question to ask in consid-
ering DLC exposure reduction options.
An evaluation of the economic feasibility of different risk options would
require a much more extensive analysis than could be carried out by the commit-
tee. Experience with evaluating other risk-reduction programs does indicate a
range of private and public costs that might be associated with reducing exposure
to DLCs in food. In the private sector, risk-reduction options may require in-
creased expenditures in the supply chain, such as costs of monitoring, certifica-
tion, substitution of higher priced inputs, or other changes in standard operations.
Consumers may also be called upon to do more to protect themselves from DLC
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
exposure. A significant lesson from prior research is that both short- and long-
term costs should be evaluated, since innovation and new approaches may cause
long-term costs to diverge from short-term costs. In the public sector, risk-man-
agement options incur costs related to monitoring, establishing programs, and
setting and enforcing standards. Again, while not fully analyzed by the commit-
tee, economic feasibility remains an important consideration in evaluating risk-
management options.
DLC Exposure Reduction
In the committee's proposed framework, DLC exposure reduction is the
declared goal, but it should be understood to be a surrogate for risk reduction. The
reason to reduce DLCs in the food supply and in diets is to reduce the potential
for adverse health effects resulting from exposure and accumulation of DLCs in
human tissue. The estimation of the risk reduction associated with any increment
of exposure reduction is, however, fraught with uncertainty, due both to the
inherent difficulties of extrapolating from test conditions in which potential haz-
ards have been identified and to the complexity and diversity of conditions under
which humans are exposed.
Numerous health effects have been ascribed to exposure to DLCs, including
dermatological damage, cancer, noninsulin-dependent diabetes in adults, neuro-
logical and immune system impairments in infants, and endocrine system disrup-
tion (see Chapter 2~. Many of these effects were identified in individuals sub-
jected to high levels of exposure (e.g., through unintended industrial releases);
others have been described in specific population groups such as the Ranch
Hands cohort. However, information on adverse health effects caused by low-
level exposure to DLCs through foods is limited.
Another source of information on the toxicity of DLCs is research on animal
models. These studies, however, have inherent limitations that affect their use in
human risk assessment. The dose-response effect of DLC exposure varies widely
among animal species and between animal models and humans. This variability
makes it difficult to establish an accurate threshold dose and leads to increased
uncertainty, particularly when extrapolating toxicity findings from animal mod-
els to humans. These studies are further limited by the need to use single com-
pounds for exposure assessments, whereas in human exposures, multiple com-
pounds and other confounding variables are present. Estimations of risk using
animal models must be approached carefully and in conjunction with other re-
sources, including epidemiological evidence.
In addition to the uncertainties and variability inherent in the DLC health-
effects data, there is wide variability in the vulnerability of human subpopula-
tions. For example, fetuses and breastfeeding infants and young children may be
especially vulnerable to the hazards posed by DLCs. This compounds the diffi-
culty of assessing the health importance of any projected decrease in DLC expo-
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
169
sure and underscores the need in evaluating proposed interventions to consider
how the anticipated reductions in exposure will be distributed.
Despite these scientific uncertainties and complexities, the assumption un-
derlying the charge to the committee was that it is desirable to reduce DLC
exposure through food. The committee embraces this assumption as an expres-
sion of sound public health policy. The committee recognizes, however, that it
will be difficult to predict the magnitude of the exposure reduction likely to result
from any proposed intervention or the health benefit of the reduction, and that the
benefits, whether measured in terms of direct health outcomes or the monetary
value of those outcomes, will vary among individuals and subpopulations. The
committee did not conduct a detailed analysis of this kind for any of the options
it identified. The framework identifies exposure reduction whether, to what
extent, and for whom it occurs to be an important question in evaluating risk-
management options.
Risk-Relationship Analysis
As discussed earlier, risk-relationship analysis goes beyond consideration of
the target risk reduction likely to be achieved by a proposed intervention it also
considers ancillary benefits and countervailing risks potentially caused by the
intervention. In the case of options for reducing DLC exposure from food, the
central source of ancillary benefits and countervailing risks are potential changes
in dietary patterns that may occur as a result of implementing a risk-reduction
strategy.
Increases in countervailing risks and ancillary benefits could occur at the
same time and to the same or different people. For example, one approach to
reduce exposure is to reduce the consumption of meat, poultry, fish, egg, and
milk products that may contain undesirable levels of DLCs. However, these
foods are sources of protein, iron, calcium, and vitamin D and, in the case of fish,
omega-3 fatty acids. Therefore, decreases in intake may increase the risk for
nutritional deficits and for some diseases. Alternatively or at the same time, there
may be corollary benefits related to the decreased consumption of some animal
foods. For example, a decreased intake of saturated fats and cholesterol is associ-
ated with a decreased risk for heart disease and possibly some cancers.
The committee concluded that it is appropriate to consider both the potential
ancillary health benefits and countervailing health risks associated with different
risk-management options, recognizing that the potential health impact of any
dietary change would vary among population subgroups and individuals depend-
ing on their nutritional needs and nutritional status at the time of the dietary
change. As discussed in Chapter 5, the committee utilized two data resources to
help predict the outcomes of certain scenarios of dietary modification that could
result from efforts to reduce DLC exposure through foods. The Continuing Sur-
vey of Food Intakes by Individuals (a food-consumption survey conducted by
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
USDA) was mapped to FDA's Total Diet Study to estimate probable DLC expo-
sure by food type for various age and gender groups. The results of the analysis,
summarized in Chapter 5, suggest that reductions in the consumption of animal
fats can reduce DLC exposure levels to varying degrees; approximately 10 per-
cent in the case of this analysis. Whether the reduction is significant for the
general population is not known. However, it could be a way to reduce exposure
to sensitive population groups in such a manner that negative nutritional conse-
quences could be avoided.
The committee also considered the possibility that regulatory interventions
to reduce DLC exposure in the diet could impose costs on the food production
system that would be reflected in higher consumer prices for food, which could in
turn affect dietary choices and nutrient intake levels to an extent that could have
negative health consequences. The impact of the price of food on nutrient avail-
ability may be significant for some low-income, sensitive, or highly exposed
groups.
The importance of such an effect depends on three factors. The first is how
much food purchases and resulting nutrient intakes respond to changes in food
prices. The second is whether any resulting changes in nutrient intakes are nutri-
tionally significant, that is, are they large enough to have possible health conse-
quences. The third is whether the changes are adverse or beneficial. Research by
Huang addresses these points.
For the general population, Huang (1996) developed a methodology to mea-
sure how a change in the price of a food-product category (e.g., beef) would
impact the consumption of that product category (the own-price elasticity effect)
and the consumption of other food-product categories (the cross-price elasticity
effect). Huang then linked these changes in consumption to changes in nutrient
intakes through the use of a database containing nutrient values of different food
products. He found that a 1 percent increase in the price of beef would reduce per
capita food energy by 0.027 percent, protein by 0.091 percent, and fat by 0.025
percent, but vitamin A would increase by 0.064 percent, with the latter change
being particularly affected by cross-product effects. Thus, while a price change
affects nutrient intake, the impact in percentage terms is much smaller than the
change in price due to the ability of consumers to attain nutrients from substitute
products. The effects of changes in nutrient intake on health depend on whether
current intakes are above or below optimal levels. Moreover, while some of the
changes in nutrient intake may adversely effect health (e.g., a reduction in pro-
tein), others may be beneficial (e.g., a reduction in fat, an increase in vitamin A).
Huang (1997) went on to assess the nutritional significance of changes in
nutrient intakes resulting from price changes by evaluating them relative to FDA
daily values for those nutrients. In this case, he evaluated the impact on nutrient
intake of a much larger change in price of 10 percent. Even at this higher level,
Huang concluded "a comparison of the nutrient quantity changes with the daily
values shows that the magnitudes of nutrient quantity changes are relatively small
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DEVELOPMENT OF POLICY OPTIONS TO REDUCE EXPOSURE
171
and, therefore, unlikely to be of nutritional significance" (p. 18~. He cautioned,
however, that the nutrient effects could exacerbate existing nutritional problems
if they occurred over prolonged periods of time.
A risk-management option to reduce DLC exposure might affect the prices
of more than one category of food products at the same time, potentially increas-
ing the impact of the option on nutrient intakes. Nevertheless, it is the committee's
judgment that the potential countervailing risk stemming from a causal link be-
tween increased production costs, increased food prices, changed dietary intakes,
and poorer health is not likely to be an important consideration in evaluating risk-
management options for reducing DLC exposure. Indeed, some of the changes in
dietary intake are likely to be beneficial for most consumers (e.g., a reduction in
fat). Unless price increases were quite large (e.g., greater than 10 percent) and
widespread across food product categories, it is likely that the general population
would be able to attain sufficient nutrients by substituting other food products for
those that became more expensive. However, the impact of price changes for the
nutritionally vulnerable could require closer scrutiny.
The committee also discussed a separate strand of economic analysis, health-
health analysis, which focuses on expenditure tradeoffs made by consumers
(Chapman and Hariharan, 1994, 1996; Keeney, 1990, 1997; Lutter et al., 1999;
Viscusi, 1994~. This approach argues that when risk-reduction options instituted
by the government cause consumers' costs to increase, consumers must spend
less on other goods, some of which promote health and safety. This decrease in
spending on health and safety could result in increases in other risks that could
offset any decrease in risk resulting from the government policy. The committee
had diverse views on whether this countervailing risk scenario was likely to be an
important factor in analyzing options to reduce DLC exposure from foods and did
not include further discussion of it in Chapter 7.
RESEARCH NEEDS
The framework for discussing intervention options ends with research needs
related to each option. The committee found that these needs were numerous and
diverse, such as testing methodologies and techniques, sampling for DLC pres-
ence in the food-supply chain, and analyses of the impacts of dietary changes on
DLC exposure. In discussing each option in Chapter 7, the committee lists key
research needs related to the possible implementation and assessment of the
option.
CONCLUSION
The proposed framework summarized in this chapter essentially poses a
series of questions that the committee considers relevant in identifying and evalu-
ating possible DLC exposure reduction options. In-depth analysis of the kind that
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
would likely be necessary to support government action would require both a
detailed description of the proposed intervention and its implementation, as well
as good data and information to answer the questions posed by the framework,
especially on the specific intervention's feasibility and likely contribution to
exposure reduction. The committee did not attempt to develop and analyze op-
tions at this level of detail.
The framework can also be used, however, to identify and test options pre-
lim~nanly to consider whether they are plausible and deserving of further refine-
ment and evaluation. In Chapter 7, how the framework can be used for this
purpose by applying it to some possible options is illustrated, and some of the
issues and data needs that would have to be addressed to more fully develop and
evaluate these options are discussed.
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Representative terms from entire chapter:
reduce dlc
