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8
Risk-Management Recommendations
and Research Priorities
Chapters 6 and 7 describe a framework for developing policy options to
reduce exposure of dioxins and dioxin-like compounds (referred to collectively
as DLCs) through food, and they illustrate how the framework might be applied
to a broad range of specific risk-management interventions. As the committee
emphasized in those chapters, there are substantial gaps in the data needed to
adopt many of the possible interventions that were identified, particularly regula-
tory interventions based on the government's food safety regulatory authority.
Tolerances were not recommended not only because of the paucity of data on
which to establish limits, but also because the committee recognized the signifi-
cant ramifications of such actions without substantive evidence to support them.
The committee considered both the scientific uncertainties in risk at current
levels of exposure and the concern within the general population about exposure
to DLCs. It further recognized that there are substantial gaps in the data that have
to be filled before many of the identified policy options can be adopted. Based on
the analysis of current data and deliberations concerning the strategic options
available to the government, the committee recommended some risk-manage-
ment actions. The committee' s recommendations are qualitative rather than quan-
titative in light of the paucity of data to support specific reduction goals, and they
fall into four categories: (1) general strategic recommendations, (2) high-priority
risk-management interventions, (3) other risk-management interventions that de-
serve consideration, and (4) research and technology development to support risk
management.
202
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 203
GENERAL STRATEGIC RECOMMENDATIONS
DLCs have been the object of concern and activity on the part of federal
regulatory agencies for many years, prompted by the large volume of evidence
demonstrating the toxicity of DLCs at low levels of exposure in animals and
suggesting the potential for DLCs to pose significant risks to humans. Important
progress has been made in reducing new environmental discharges of DLCs.
With respect to the problem of DLC exposures through food, however, most of
the efforts have focused on assessment of the potential risks of DLCs, as dis-
cussed in Chapter 2. This has included substantial investments in toxicity testing
and extended interagency efforts to refine and reach agreement on DLC risk
assessments. This effort has been worthwhile. Risk assessment provides the es-
sential starting point for risk management and, for any important problem, it is
desirable to have the most definitive assessment of risk that available data and
understanding will permit. Uncertainty is, however, inherent in risk assessment
generally, and uncertainties in assessment of the risks posed by exposure to DLCs
through food will persist for the foreseeable future. These uncertainties are not,
however, an obstacle to sound and effective risk management.
Given that the risk assessments that have been conducted have raised con-
cerns about the health impacts of DLCs, and that there is no benefit but possible
harm from DLC exposure through foods, the committee considers it appropriate
for the federal government to focus its efforts on exposure reduction strategies.
To move effectively toward reducing human exposure to DLCs through
foods, the federal government should begin by pursuing the following strategic
courses of action: (1) establish an integrated risk-management strategy and action
plan, (2) foster collaboration between the government and the private sector to
reduce DLCs, and (3) invest in the data required for effective risk management.
Develop an Integrated Risk-Management Strategy and Action Plan
Justification
DLC exposure through food is a widely shared problem in the food system.
It results not from the actions of any one segment of the food system, but from the
complex interaction of widespread environmental contamination and the estab-
lished practices and behaviors of animal producers, food processors, and con-
sumers. Its solution requires action across the system, based on consideration of
all the factors that contribute to exposure and all the possibilities for reducing
exposure.
At the federal level, regulatory responsibility for DLCs in food is shared by
three agencies: the U.S. Department of Health and Human Services' Food and
Drug Administration (FDA), the U.S. Department of Agriculture's (USDA) Food
Safety and Inspection Service (FSIS), and the U.S. Environmental Protection
Agency (EPA), and by multiple other program offices. For example, FDA's
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
Center for Food Safety and Applied Nutrition is responsible for setting regulatory
limits on the levels of DLCs that may lawfully be present in human food and for
regulating the practices of food processors. However, FDA's Center for Veteri-
nary Medicine is responsible for regulating DLCs in animal feeds. A third orga-
nizational component of FDA, the Office of Regulatory Affairs, manages the
field function of the agency, which involves conducting inspections, product
sampling, and enforcement, and often requires balancing, in the face of scarce
resources, the food-related functions of FDA with the agency's responsibilities
for drugs and other medical products. FSIS has jurisdiction over the safety of
meat and poultry, which would include enforcement of any regulatory restric-
tions that might be placed on the level of DLCs in these products. EPA sets limits
on permissible discharges of DLCs into waterways based on assessments of the
resulting impact of DLCs on the safety of fish. At the state and local level,
multiple health, agriculture, and natural resource agencies can be involved in
issuing and enforcing advisories and regulatory restrictions on the harvesting and
consumption of fish from contaminated waters.
In addition to these regulatory agencies, a wider set of federal agencies
would be involved in devising and implementing any DLC risk-management
interventions that involve changing food-consumption patterns or conducting
research. For example, multiple agencies within USDA and the U.S. Department
of Health and Human Services collaborate in developing the government's Di-
etary Guidelines for Americans, and both departments have nutrition education
programs. In addition, the Food and Nutrition Service within USDA sets policy
for the National School Lunch Program and other government feeding programs,
while USDA's Agricultural Marketing Service acts as the government's purchas-
ing agent for these programs. Most of the regulatory agencies have food safety
research programs that could contribute to the development of risk-management
interventions, but so also do USDA's Agricultural Research Service and its Co-
operative State, Research, Education and Extension Service, the Centers for Dis-
ease Control and Prevention, and other federal agencies.
Recommendation
The committee recommends that the sponsoring agencies empower an
interagency coordination group with the authority and mandate to develop
and to implement a single, integrated risk-management strategy and action
plan. No one agency has the mandate, resources, expertise, or authority to ad-
dress DLC exposure through food on a system-wide basis. With an integrated,
comprehensive, and system-wide approach however, it will be possible to set
achievable and widely shared goals for DLC exposure reduction, to identify
optimal risk-management interventions, to set priorities, and to make the best use
of available government resources. An integrated approach on the part of the
federal government would also help to ensure effective interaction and collabora-
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 205
tion between the public and private sectors and help to minimize private sector
disruptions and costs.
The committee recognizes the difficulty of working across agency lines on a
problem of this complexity. There will be a need to establish clearly defined
leadership for the effort, accountability for results, and mechanisms for on-going
collaboration and coordination.
Foster Collaboration Between the Government and the Private Sector
to Reduce DLCs in the Food Supply
Justification
No one desires the presence of DLCs in food, and no one set of participants
in the food system can fairly be assigned sole responsibility and accountability
for their presence or for actions needed to reduce foodborne exposure to DLCs.
DLC exposure through food is a shared problem requiring shared, collaborative
solutions. This does not preclude the possibility that regulatory interventions will
play a role at some point in reducing DLC exposure, but, as discussed in Chapters
6 and 7, the committee sees no immediate regulatory solutions. There is instead a
need, among other things, to generate data and develop practices in the food-
production and processing systems that will reduce DLC levels and resulting
exposures over time. This will require active collaboration between the federal
government and the private sector.
Recommendation
The committee recommends that, as part of the process of developing an
integrated risk-management strategy and action plan, the federal govern-
ment, through an interagency coordination group, create an atmosphere
and program of collaboration with the private sector. This recommendation is
premised on both the government and industry being willing to define and ac-
tively approach the problem of DLC exposure through food as a shared problem.
If that willingness exists, the government should establish an organizational focal
point and define processes through which government and the private sector
could collaborate in developing and implementing the integrated strategy and
action plan for reducing DLC exposure through food.
Invest in the Data Required for Effective Risk Management
Justification
As discussed in Chapters 6 and 7, there are significant gaps in the data
required to devise, implement, and evaluate risk-management interventions to
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
reduce DLC exposure through food. The lack of data is most glaring with respect
to consideration of options to reduce DLC levels at the animal production stage
and in human food. To target and prioritize efforts to reduce DLCs at these stages
and to determine what reductions are desirable and feasible, the critical starting
point is good information on the current levels of DLCs in forage, feeds, and feed
components, across geographical regions, and in the array of human foods in
which DLCs are found. As discussed in Chapters 4 and 5, however, the available
data on these points are very limited. A reliable, reasonably complete picture of
the current levels and distribution of DLCs in animal feeds and human food is
lacking. There is also insufficient data on the levels and distribution of DLC body
burdens in the general population and among sensitive and highly exposed sub-
groups. Body burden data are a prerequisite for evaluating the effectiveness of
efforts to reduce DLC exposure through food.
Recommendation
The committee recommends that a commitment of resources by all spon-
soring agencies for data collection be a central element of any risk-manage-
ment strategy and action plan for reducing DLC exposure through food. The
committee recognizes that DLC analysis is expensive and that expense has been
a limiting factor in data-collection efforts to date. In the committee's judgment,
however, a commitment to risk management to reduce DLC exposure necessi-
tates a commitment to data collection. As discussed below, the committee recom-
mends, as one of its research priorities, an effort to develop less costly analytical
methods for DLCs in feeds and food.
HIGH-PRIORITY RISK-MANAGEMENT INTERVENTIONS
The committee has identified two areas that it believes deserve high-priority
attention as part of any risk-management strategy for reducing DLC exposure
through food. The committee recommends that the government focus its initial
risk-management interventions on: (1) interrupting the cycling of DLCs through
forage, animal feeds, and food-producing animals, and (2) reducing DLC expo-
sure in girls and young women in order to protect fetuses and breastfeeding
infants from exposure to DLCs.
Interrupt the Cycling of DLCs Through Forage, Animal Feeds, and
Food-Producing Animals
Justification
As discussed in Chapter 4, animal forage and feeds are primary pathways for
DLC contamination of the human food supply. This occurs as a result of the
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 207
direct contamination of forage and plants used for animal feeds, typically by
airborne deposition of DLCs. When animals consume contaminated forage and
feeds, DLCs are stored in their fat and subsequently enter the human food supply.
In addition, several billion pounds of rendered animal fat are used annually as a
component of animal feeds, which results in the recycling of DLCs back through
the feed and the possibility of increasing levels of DLCs in meat and other
animal-derived food products (see Figure 4-1~.
Recommendations
The committee recommends that the government's risk-management
strategy for DLCs give high-priority attention to reducing the contamina-
tion of animal forage and feeds and interrupting the recycling of DLCs that
results from the use of animal fat in animal feeds. The committee considers the
animal feed and animal production stages of the food system to be key leverage
points for reducing DLC exposure through food because it stops DLCs at their
primary point of entry into the human food supply. This is the only available
means the committee could identify for preventing DLC contamination of human
food. At subsequent stages human exposure can be reduced only by discarding or
otherwise avoiding consumption of DLC-contaminated food.
While FDA has the authority to set legally binding limits (i.e., tolerances) on
the levels of DLCs in animal feeds, the committee is not recommending such
regulatory action at this time. This is due to the current lack of data to support
binding tolerances, the consequences of trying to establish limits without ad-
equate supportive evidence, and the committee's belief that there is a need for
collaboration between the government and the animal production industry to
develop alternative feeding practices and to overcome other practical obstacles to
reducing DLCs in animal forage and feeds that may obviate the need for regula-
tory action in the future.
As an initial step, the government, in collaboration with the animal
production and feed industries, and directed by an interagency coordination
group, should establish a nationwide data-collection effort and data reposi-
tory on the levels of DLCs in animal forage and feeds, which should be
accessible for both public and private use. An expanded data-collection effort
by the government and industry and the pooling of the data would provide a
better understanding of current DLC levels in forage and feeds, including their
sources and geographic distribution. This would in turn provide a basis for devis-
ing and targeting specific interventions to reduce DLCs in forage and feeds.
The government and industry should also begin collaborating immedi-
ately to define voluntary guidelines for good animal feeding and production
practices that would reduce DLC levels in forage and feeds and would mini-
mize other potential sources of DLC exposure in animal production. Such
guidelines could include avoiding forage or feeds obtained from areas known to
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
have high levels of DLC contamination. They could also include criteria for the
use of animal fat in animal feeds, which would result in reducing DLC levels in
the finished feeds, and criteria for the use of non-DLC containing materials in
animal enclosures and in feed packaging and transportation. The use of "cleaner"
(i.e., uncontaminated) fats is not a practical alternative at the present time because
of the high cost of analysis that would be needed to implement widespread
testing.
The committee further recommends that the government, in collabora-
tion with the animal production industry, identify means to achieve the
reduction or elimination of DLC-containing animal fat as a component of
animal feeds. This would require, among other things, the development of crite-
ria for determining what constitutes an acceptable use of animal fat and economi-
cally feasible analytical methods for distinguishing acceptable from unacceptable
animal fat. It would also require the development of alternative uses or acceptable
disposal methods for the large quantity of animal fat now used in animal feeds.
However, the committee recognizes that reducing or eliminating the use of ani-
mal fat as a component of animal feeds could have unintended negative conse-
quences: (1) increased cost of food, (2) problems of animal waste disposal, (3)
increased food spoilage, and (4) changes in the taste of food that consumers find
unacceptable.
Only when more complete data are generated on DLC levels in forage
and feeds, and a better understanding is developed of how DLC contamina-
tion can be avoided, should the government consider setting legally binding
limits on DLCs in forage and feeds.
Reducing DLC Exposure in Girls and Young Women
Justification
As discussed in Chapter 2, fetuses and breastfeeding infants may be at par-
ticular risk from exposure to DLCs. This is due to the potential for DLCs to cause
adverse neurodevelopmental, neurobehavioral, and immune system effects in
developing systems, combined with the potential for in utero exposure of the
fetus to DLCs and exposure of breastfeeding infants to relatively high levels of
DLCs in breast milk. These exposures are a result of the body burden of DLCs
that girls and young women accumulate during their childhood, adolescence, and
young adult years. Data suggest that, due to the bioaccumulation phenomenon,
reduction of DLC intake during pregnancy has no significant impact on the
mother's body burden or on the baby's exposure in utero or through breastfeeding.
The committee recommends the following options as ways to reach a broad
number of individuals with the least potential undesired outcomes.
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 209
Recommendations
The committee recommends that the government place a high public
health priority on reducing DLC intakes by girls and young women in the
years well before pregnancy is likely to occur.
Such reductions can be achieved by reducing the intake of animal fat among
this population. The committee therefore recommends, as an immediate in-
tervention, that the government take steps to increase the availability of
foods low in animal fat in government-sponsored school breakfast and lunch
programs and in child- and adult-care food programs. Specifically, the com-
mittee recommends that the National School Lunch Program increase the
availability of low-fat (1 percent) and skim milk and have the option of
offering other milks. Because the current law (Richard B. Russell National
School Lunch Act, amended Dec. 8, 2000, §9~2~) favors the provision of whole
milk, it should be amended to require that schools offer low-fat and skim milk
and have the option of offering reduced-fat (2 percent fat) or whole (3.5 percent
fat) milk. The committee further recommends that participants in the Spe-
cial Supplemental Nutrition Program for Women, Infants and Children be
encouraged, except for children under 2 years of age, to choose low-fat or
skim milk and low-fat versions of other animal-derived foods in their food
packages.
In addition, to reduce other sources of animal fat, the committee recom-
mends that USDA's Economic Research Service undertake detailed analyses
of the feasibility of and barriers to setting limits on the amount of saturated
fat that can be present in individual meals in the National School Lunch
Program. There are insufficient data to establish limits on saturated fat in school
lunch and breakfast meals to reduce DLC exposure. Detailed analyses are needed
to determine an appropriate level of saturated fat to reduce DLC exposure and to
promote and maintain good nutrition habits.
Although data are insufficient to set limits on saturated fat intake to reduce
DLC exposure, there is a strong body of evidence to support the benefit of
reducing saturated fat intake to reduce the risk of chronic disease. The Dietary
Guidelines for Americans recommend that less than 10 percent of calories should
be derived from saturated fat. School lunches are currently required to provide
less than this level when the fat content of the meals is averaged over a week.
There is currently no saturated fat guideline for individual meals. If a limit were
established for saturated fat in individual meals served in the National School
Lunch Program, more lean meat, poultry, and seafood products would be used in
place of high-fat versions of these foods, which would lower levels of animal fat
(and thus DLCs) in school lunches. While potential changes in the school lunch
program are being considered, there should be ongoing educational efforts aimed
at reducing the consumption of animal fat by girls and young women.
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
As discussed in Chapter 5, substituting low-fat or skim milk for whole milk,
especially when coupled with other substitutions of foods lower in animal fat
such as selecting lean cuts of meat, poultry, low-fat fish, and low-fat cheeses,
could significantly reduce DLC intakes and resulting body burdens of DLCs in
girls and young women in the crucial years preceding pregnancy. Reducing DLC
intakes in this way is the only practicable intervention the committee could
identify that would, in the relatively near term, reduce DLC exposure to fetuses
and breastfeeding infants, which appear to be the populations most vulnerable to
the toxicity of DLCs.
OTHER RISK-MANAGEMENT INTERVENTIONS
THAT DESERVE CONSIDERATION
Although more data are needed, there are several other specific interventions
that could be considered as part of an integrated risk-management strategy and
action plan for reducing DLC exposure through food. These include: (1) reducing
DLC discharge sources in animal production areas, (2) removing DLC residues
from foods during processing, (3) providing advisories and education to highly
exposed populations, and (4) educating the general population about strategies
for DLC exposure reduction.
Reducing DLC-Discharge Sources in Animal Production Areas
Justification
As discussed in Chapter 3, the largest quantifiable source of new DLC for-
mation in the United States is the backyard burning of yard, home, and farm
waste. To the extent this occurs in animal production areas or in areas where
animal feed is produced, it is potentially an important pathway for DLC contami-
nation of food and resulting human exposure.
Recommendation
The committee recommends that the government consider, as part of an
integrated risk-management strategy, a focused effort to reduce unregulated
(e.g., backyard) burning, especially in animal production areas. This could be
pursued initially as an element of the collaborative effort with the animal produc-
tion industry to reduce DLC contamination of animal forage and feeds. The
committee has not examined whether there are practicable regulatory interven-
tions to address this potential source of DLCs in the environment.
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 211
Removing DLC Residues from Foods During Processing
Justification
DLCs can directly contaminate human foods through airborne deposition on
food plants and soils. As discussed in Chapter 4, as much as 25 percent of DLC
exposure through foods may come from this source. In such cases, the DLCs and
DLC-contaminated soils typically adhere to the external surfaces of the plant and
its edible portion, including vegetables, fruits, and grains. These DLCs can, to a
significant extent, be prevented from entering the food supply at the food-pro-
cessing stage through readily available cleaning and processing measures and by
peeling root and waxy-coated vegetables. In addition, the physical removal of fat
from meat products through trimming prevents DLCs from entering the human
food supply.
Recommendation
The committee recommends that the government explore, with the food
industry, practicable steps to reduce, during processing, the DLC contami-
nation of food. This effort could result in the development of voluntary good
manufacturing practices for reducing DLCs in food. Consideration and adoption
of regulatory measures in this area would require more data than currently exist
on the magnitude of the DLC reductions that could be achieved through process-
ing, as well as on the feasibility and cost of achieving these reductions.
Providing Advisories and Education to Highly Exposed Populations
Justification
As discussed in Chapter 5, there are population groups that for economic,
cultural, or other reasons consume large amounts of fish and marine mammals
that tend to be high in DLCs. These highly exposed groups, and in particular
sensitive members of these groups (such as developing fetuses and breastfeeding
infants), may be at higher risk of adverse health effects from DLCs than the
general population. Currently, EPA and some state and local agencies issue advi-
sories on the consumption of fish caught in highly contaminated areas.
Recommendation
The committee recommends that the government continue collaborat-
ing with state and local officials to provide up-to-date fishing advisories on
waters that are highly contaminated with DLCs. In addition, the committee
recommends that the government work with highly exposed populations to de-
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
velop information and education programs about the potential risks of DLCs and
offer practical ideas for reducing DLC exposure, taking into account each group's
economic and cultural situation.
Educating the General Population About
Strategies for Reducing Exposure to DLCs
Justification
Within the general population there is much that could be done at the indi-
vidual and household levels to reduce exposure to DLCs through food. The
intervention that could be the most immediate and could have the most impact is
for individuals to reduce their intake of animal fat. This could be done by reduc-
ing the consumption of fat from meat, poultry, and fish (e.g., by trimming and
discarding their excess fat) and by choosing lower-fat versions of these foods.
Individuals could reduce DLC intakes by washing and, as appropriate, peeling
root and waxy-coated vegetables prior to consumption.
Achieving changes in dietary patterns and food preparation practices is diffi-
cult. The government has been communicating the fat reduction message, based
on the U.S. Dietary Guidelines, for a number of years. While fat intake has
declined as a percentage of calories, it has remained fairly constant in absolute
terms while total calorie intake has risen. The communication of the fat-reduction
message is further complicated in the case of DLCs since one of the major
sources of DLCs in the diet fish has nutritional advantages as a source of
protein and potentially "healthy" fats, such as the omega-3 fatty acids. Further-
more, while it may seem that the provision of information about DLCs on food
labels would be an alternative educational approach, the limited range of foods
tested and the complexities of the toxicity equivalents measurement system and
its interpretation could mislead consumers about the DLC content in food.
Recommendations
The committee recommends that the government continue (and explore
ways to enhance) its promotion of the U.S. Dietary Guidelines, including the
message to limit intake of saturated fat. This message has the potential to
produce health benefits that go well beyond the reduction of DLC exposure,
including reductions in the risk of cardiovascular disease and cancer. The com-
mittee further recommends that the government consider linking, in its Di-
etary Guidelines and associated information campaigns, the saturated fat
reduction message based on cardiovascular disease and cancer with the mes-
sage that reducing saturated fat has the added benefit of reducing exposure
to DLCs and other lipophilic contaminants. The committee recognizes that
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 213
communicating clear and effective messages on this complex subject is difficult,
and that great care must be exercised in crafting messages that do not mislead or
confuse consumers by making the messages ineffective for their intended pur-
poses or by causing dietary changes that could be detrimental. As discussed
below, behavioral research may be needed to craft effective messages.
RESEARCH AND TECHNOLOGY DEVELOPMENT
TO SUPPORT RISK MANAGEMENT
As one of its general strategic recommendations, the committee recommends
above that the government focus its efforts on exposure-reduction strategies and
that it invest in data collection to support risk management. There is also a need,
in the committee's judgment, for a broader research and technology development
agenda to support risk management. Among the many possible subjects for such
efforts, the committee recommends that the government consider placing a prior-
ity on the following: (1) low-cost analytical methods development and toxicity
equivalents review, (2) research to support removal of DLCs from animal feeds,
(3) expansion of the National Health and Nutrition Examination Survey's
(NHANES) data collection on DLC body burdens, (4) research on the effects of
dietary DLCs on fetuses and breastfeeding infants, (5) behavioral research on
achieving dietary change, and (6) predictive modeling studies on DLCs in the
food supply.
Analytical Methods Development and Toxicity Equivalents Review
Justification
As discussed in Chapter 2, the analysis of forage, feeds, and food commodi-
ties for DLC contamination is expensive, and this expense has been a limiting
factor in the collection of data to design and evaluate risk-management interven-
tions. In addition, accuracy and reproducibility in DLC measurements are often
compromised by analytical variances and measurement bias.
Recommendation
The committee recommends that the government invest in the develop-
ment of cost-effective analytical methods that will make possible a signifi-
cantly larger volume of DLC testing to support risk management. As part of
this effort, the committee recommends that the government review the current
toxicity equivalents assessment standards to ensure that the standards accurately
reflect the most current knowledge of the toxicity contribution of various DLC
congeners, particularly for low-level exposures from foods.
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214
Justification
DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
Research to Support Removal of DLCs from Animal Feeds
The committee has recommended reducing the contamination of animal for-
age and feeds and reducing the recycling of DLCs that result from the use of
animal fat in animal feeds as high-priority risk-management interventions.
Achieving these goals may require significant adjustments in animal feeding
practices and the development of alternative uses or acceptable disposal solutions
for the several billion pounds of animal fat that are used annually in animal
production systems.
Recommendation
The committee recommends that the government sponsor research on
the economics of animal production and current animal feeding practices,
with a view toward identifying economically feasible alternatives to current
practices that will result in significant reductions in DLC contamination of
animal forage and feeds. To complement the economic research, the committee
recommends that the government sponsor research on disposal possibilities and
alternative uses of animal fat, including use as a biofuel.
Expansion of Data Collection on DLC Body Burdens
Justification
In 1999, NHANES began collecting measurements of serum dioxins from a
subsample of the population examined in this large, recurring survey on diet and
health. These measurements, if continued over time, will enable scientists to
monitor trends in DLC body burdens. When these data are combined with data
from FDA's Total Diet Study and the USDA Economic Research Service's food-
consumption data as a component of the continuing NHANES, it will be possible
to develop a more refined understanding of DLC exposure through food, includ-
ing its geographic and population-group variability and its impact on body bur-
dens among various components of the population. Such data will be essential to
sound risk-management decision-making over the long term, including the con-
sideration of possible regulatory interventions.
Recommendations
The committee recommends that the government expand data collection
of DLC body burdens to expedite the development of a reasonably represen-
tative and reliable database on DLC exposure patterns and body burdens.
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RISK-MANAGEMENT RECOMMENDATIONS AND RESEARCH PRIORITIES 215
DLC analyses in human subjects are expensive and invasive to the subject, which
makes the collection of new body burden data difficult. Thus, to supplement the
NHANES data collection on DLC body burdens, the committee recommends that
the government support continued and expanded DLC assays of tissues collected
from existing cohorts and control groups, such as in the Ranch Hands study
(discussed in Chapter 2), which has a large sample base of subjects with back-
ground or low-level DLC exposures.
Research on the Effects of Dietary DLCs
on Fetuses and Breastfeeding Infants
Justification
From a public health perspective, the committee places its highest risk-
management priority on reducing the DLC exposure of fetuses and breastfeeding
infants.
Recommendation
To support and further focus risk-management initiatives in this area,
the committee recommends that the government sponsor a prospective co-
hort study (that includes monitoring breast-milk samples) to examine the
health effects over time of pre- and postnatal DLC exposure of infants. The
results of such a study would help public health officials and risk managers better
understand the nature and severity of the risks posed by exposure to DLCs at this
critical developmental phase of life, and thus help guide and set priorities for
future risk-management initiatives. In addition, the committee recommends that
breast-milk monitoring in sentinel populations be conducted to assess the magni-
tude of exposure through this source.
Behavioral Research on Achieving Dietary Change
Justification and Recommendation
To the extent that the government's risk-management strategy relies on
achieving dietary changes to reduce DLC exposure, the committee recom-
mends that it sponsor behavioral research to better understand how such
changes can be brought about. It is clear from experience over the past decade
that formulation and communication of a scientifically sound message about diet
and health is not enough to change long-established dietary patterns. Dietary
patterns are complex human behaviors that are affected by many factors and vary
among individuals. Careful research is needed to better understand the phenom-
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DIOXINS AND DIOXIN-LIKE COMPOUNDS IN THE FOOD SUPPLY
enon and to develop educational and other techniques for improving dietary
patterns.
Predictive Modeling Studies on DLCs in the Food Supply
Justification
DLCs move through the atmospheric, terrestrial, and aquatic environments
and into the human food supply in complex ways. In designing interventions to
reduce DLC exposure through food, it is important to be able to model the
movement of DLCs and their ultimate biomagnifications through the food chain,
as well as to be able to predict how proposed interventions will affect levels in
food and, in turn, human exposure and body burdens.
Recommendation
The committee recommends that the government sponsor research to
develop improved predictive modeling tools and that it apply them in studies
aimed at assessing the DLC-reduction effects of potential interventions.
CONCLUSION
DLCs are an undesirable contaminant in food, and there are good public
health reasons for reducing DLC exposure through food, especially among highly
exposed and sensitive populations. The committee recognizes there are serious
limitations in the data available for managing the risks posed by DLCs in food
and that, in light of these limitations and remaining uncertainties in risk assess-
ments on DLCs, it is premature to recommend traditional food-safety regulatory
remedies for the DLC problem. There are, however, a number of steps the gov-
ernment could take to reduce DLC exposure among the most vulnerable popula-
tion groups in the short term and to significantly reduce DLC exposure within the
general population in the long term. These steps have been outlined in this con-
cluding chapter.
Representative terms from entire chapter:
animal fat
