A Review of the Effectiveness of Current US Policies on Antimicrobial Use in Meat and Poultry Production

PURPOSE

Industrial food animal production accounts for most animal-source protein consumed in the USA. These operations rely on an array of external inputs, which can include antimicrobials of medical importance. The use of these drugs in this context has been the subject of public health debate for decades because their widespread use contributes to the selection for and proliferation of drug-resistant bacteria and their genetic determinants. Here, we describe legislative and regulatory efforts, at different levels of governance in the USA, to curtail food animal consumption of medically important antimicrobials.

RECENT FINDINGS

The features and relative success of the US efforts are examined alongside those of selected member states (Denmark and the Netherlands) of the European Union. Evaluation of efforts at all levels of US governance was complicated by shortcomings in prescribed data collection; nevertheless, available information suggests deficiencies in policy implementation and enforcement compromise the effectiveness of interventions pursued to date. The political will, robust systems for collecting and integrating data on antimicrobial consumption and use, and cross-sectoral collaboration that have been integral to the success of efforts in Denmark and The Netherlands have been notably absent in the USA, especially at the federal level.

A Food Systems Approach To Healthy Food And Agriculture Policy

Food has become a prominent focus of US public health policy. The emphasis has been almost exclusively on what Americans eat, not what is grown or how it is grown. A field of research, policy, and practice activities addresses the food-health-agriculture nexus, yet the work is still often considered "alternative" to the mainstream. This article outlines the diverse ways in which agriculture affects public health. It then describes three policy issues: farm-to-school programming, sustainability recommendations in the Dietary Guidelines for Americans, and antibiotic use in animal agriculture. These issues illustrate the progress, challenges, and public health benefits of taking a food systems approach that brings together the food, agriculture, and public health fields.

Antimicrobial resistance and biological governance: explanations for policy failure

The paper reviews the state of policy on antimicrobial use and the growth of antimicrobial resistance (AMR). AMR was anticipated at the time of the first use of antibiotics by their originators. For decades, reports and scientific papers have expressed concern about AMR at global and national policy levels, yet the problem, first exposed a half-century ago, worsened. The paper considers the explanations for this policy failure and the state of arguments about ways forward. These include: a deficit of economic incentivisation; complex interventions in behavioural dynamics; joint and separate shifts in medical and animal health regimes; consumerism; belief in technology; and a narrative that in a 'war on bugs' nature can be beaten by human ingenuity. The paper suggests that these narratives underplay the biological realities of the human-animal-biosphere being in constant flux, an understanding which requires an ecological public health analysis of AMR policy development and failure. The paper suggests that effective policy change requires simultaneous actions across policy levels. No single solution is possible, since AMR is the result of long-term human intervention which has accelerated certain trends in the evolution of a microbial ecosystem shared by humans, animals and other biological organisms inhabiting that ecosystem. Viewing the AMR crisis today through an ecological public health lens has the advantage of reuniting the social-ecological and bio-ecological perspectives which have been separated within public health.

Evaluation of the association between maternal smoking, childhood obesity, and metabolic disorders: a national toxicology program workshop review

BACKGROUND

An emerging literature suggests that environmental chemicals may play a role in the development of childhood obesity and metabolic disorders, especially when exposure occurs early in life.

OBJECTIVE

Here we assess the association between these health outcomes and exposure to maternal smoking during pregnancy as part of a broader effort to develop a research agenda to better understand the role of environmental chemicals as potential risk factors for obesity and metabolic disorders.

METHODS

PubMed was searched up to 8 March 2012 for epidemiological and experimental animal studies related to maternal smoking or nicotine exposure during pregnancy and childhood obesity or metabolic disorders at any age. A total of 101 studies-83 in humans and 18 in animals-were identified as the primary literature.

DISCUSSION

Current epidemiological data support a positive association between maternal smoking and increased risk of obesity or overweight in offspring. The data strongly suggest a causal relation, although the possibility that the association is attributable to unmeasured residual confounding cannot be completely ruled out. This conclusion is supported by findings from laboratory animals exposed to nicotine during development. The existing literature on human exposures does not support an association between maternal smoking during pregnancy and type 1 diabetes in offspring. Too few human studies have assessed outcomes related to type 2 diabetes or metabolic syndrome to reach conclusions based on patterns of findings. There may be a number of mechanistic pathways important for the development of aberrant metabolic outcomes following perinatal exposure to cigarette smoke, which remain largely unexplored.

CONCLUSIONS

From a toxicological perspective, the linkages between maternal smoking during pregnancy and childhood overweight/obesity provide proof-of-concept of how early-life exposure to an environmental toxicant can be a risk factor for childhood obesity.

Exporting obesity: US farm and trade policy and the transformation of the Mexican consumer food environment

Obesity has reached epidemic proportions, in the United States as well as among its trade partners such as Mexico. It has been established that an "obesogenic" (obesity-causing) food environment is one influence on obesity prevalence. To isolate the particular role of NAFTA, the North American Free Trade Agreement, in changing Mexico's food environment, we plotted the flow of several key products between the United States and Mexico over the 14-year NAFTA period (1994-2008) and situated them in a broader historical context. Key sources of USDA data include the Foreign Agricultural Service's Global Agricultural Trade System, its official repository for current and historical data on imports, exports and re-exports, and its Production, Supply, and Distribution online database. US export data were queried for agricultural products linked to shifting diet patterns including: corn, soybeans, sugar and sweeteners, consumer-oriented products, and livestock products. The Bureau of Economic Analysis' Balance of Payments and Direct Investment Position Data in their web-based International Economic Accounts system also helped determine changes in US direct investment abroad from 1982 to 2009. Directly and indirectly, the United States has exported increasing amounts of corn, soybeans, sugar, snack foods, and meat products into Mexico over the last two decades. Facilitated by NAFTA, these exports are one important way in which US agriculture and trade policy influences Mexico's food system. Because of significant US agribusiness investment in Mexico across the full spectrum of the latter's food supply chain, from production and processing to distribution and retail, the Mexican food system increasingly looks like the industrialized food system of the United States.

A macroepigenetic approach to identify factors responsible for the autism epidemic in the United States

The number of children ages 6 to 21 in the United States receiving special education services under the autism disability category increased 91% between 2005 to 2010 while the number of children receiving special education services overall declined by 5%. The demand for special education services continues to rise in disability categories associated with pervasive developmental disorders. Neurodevelopment can be adversely impacted when gene expression is altered by dietary transcription factors, such as zinc insufficiency or deficiency, or by exposure to toxic substances found in our environment, such as mercury or organophosphate pesticides. Gene expression patterns differ geographically between populations and within populations. Gene variants of paraoxonase-1 are associated with autism in North America, but not in Italy, indicating regional specificity in gene-environment interactions. In the current review, we utilize a novel macroepigenetic approach to compare variations in diet and toxic substance exposure between these two geographical populations to determine the likely factors responsible for the autism epidemic in the United States.

Agricultural policy and childhood obesity: a food systems and public health commentary

For thirty-five years, U.S. agriculture has operated under a "cheap food" policy that spurred production of a few commodity crops, not fruit or vegetables, and thus of the calories from them. A key driver of childhood obesity is the consumption of excess calories, many from inexpensive, nutrient-poor snacks, sweets, and sweetened beverages made with fats and sugars derived from these policy-supported crops. Limiting or eliminating farm subsidies to commodity farmers is wrongly perceived as a quick fix to a complex agricultural system, evolved over decades, that promotes obesity. Yet this paper does set forth a series of policy recommendations that could help, including managing commodity crop oversupply and supporting farmers who produce more fruit and vegetables to build a healthier, more balanced agricultural policy.

Reproductive health and the industrialized food system: a point of intervention for health policy

What food is produced, and how, can have a critical impact on human nutrition and the environment, which in turn are key drivers of healthy human reproduction and development. The US food production system yields a large volume of food that is relatively low in cost for consumers but is often high in calories and low in nutritional value. In this article we examine the evidence that intensive use of pesticides, chemical fertilizers, hormones, antibiotics, and fossil fuel in food production, as well as chemicals in food packaging, are potentially harmful to human reproductive and developmental health. We conclude that policies to advance a healthy food system are necessary to prevent adverse reproductive health effects and avoid associated health costs among current and future generations. These policies include changes to the Farm Bill and the Toxic Substances Control Act, and greater involvement by the health care sector in supporting and sourcing food from urban agriculture programs, farmers' markets, and local food outlets, as well as increasing understanding by clinicians of the links between reproductive health and industrialized food production.

Food Systems and Public Health: Linkages to Achieve Healthier Diets and Healthier Communities

The Airlie Conference on "Food Systems and Public Health: Linkages to Achieve Healthier Diets and Healthier Communities" was convened to discuss how we as a nation can shift toward promoting healthy, sustainably produced foods that are aligned with national dietary and health priorities; the most strategic changes in policy, governance and practices that can help this shift occur; and identify knowledge gaps and policy-relevant research needs. This special theme issue presents papers emanating from the conference, and policy-relevant research and action recommendations from the small group breakout sessions.

Research and Action Priorities for Linking Public Health, Food Systems, and Sustainable Agriculture: Recommendations from the Airlie Conference

One hundred leading researchers, practitioners, and advocates in public health, health care, nutrition, obesity, economics, sustainable agriculture, and food systems met at the Airlie Conference Center in April 2009 to discuss creating linkages among food systems, public health, and sustainable agriculture in order to achieve healthier diets, healthier communities, and a healthier planet. Participants convened in small groups to explore and discuss research that is needed to create a health-based and sustainable food system. The discussion and key recommendations from the small breakout sessions are presented.

Mercury exposure, nutritional deficiencies and metabolic disruptions may affect learning in children

Among dietary factors, learning and behavior are influenced not only by nutrients, but also by exposure to toxic food contaminants such as mercury that can disrupt metabolic processes and alter neuronal plasticity. Neurons lacking in plasticity are a factor in neurodevelopmental disorders such as autism and mental retardation. Essential nutrients help maintain normal neuronal plasticity. Nutritional deficiencies, including deficiencies in the long chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, the amino acid methionine, and the trace minerals zinc and selenium, have been shown to influence neuronal function and produce defects in neuronal plasticity, as well as impact behavior in children with attention deficit hyperactivity disorder. Nutritional deficiencies and mercury exposure have been shown to alter neuronal function and increase oxidative stress among children with autism. These dietary factors may be directly related to the development of behavior disorders and learning disabilities. Mercury, either individually or in concert with other factors, may be harmful if ingested in above average amounts or by sensitive individuals. High fructose corn syrup has been shown to contain trace amounts of mercury as a result of some manufacturing processes, and its consumption can also lead to zinc loss. Consumption of certain artificial food color additives has also been shown to lead to zinc deficiency. Dietary zinc is essential for maintaining the metabolic processes required for mercury elimination. Since high fructose corn syrup and artificial food color additives are common ingredients in many foodstuffs, their consumption should be considered in those individuals with nutritional deficits such as zinc deficiency or who are allergic or sensitive to the effects of mercury or unable to effectively metabolize and eliminate it from the body.

Today's Food System: How Healthy Is It?

With its focus on the quantity of production, often to the exclusion of other goals, today's food system is on an unsustainable course. The problem begins with and is driven by industrialized production of both crops and animals. Industrialization is a product of technological change, public policy, and, most recently, globalized trade. The lack of sustainability derives from reliance on the intensive use of nonrenewable and hard-to-renew resources-soil, antibiotics, fresh water, and fossil fuels, for example-but also from the waste and pollution created by the industrial model. For at least 50 years, American agriculture policies have promoted production of, and ultimately lower market prices for, commodity crops like corn, wheat, and soybeans. Over the last 3 decades in particular, these "cheap food" policies have exacerbated the negative impacts of an industrialized agriculture on the health of the agro-ecosystem, as well as on the health of the humans who must share and be sustained by it. Sustainability and health are two sides of the same food system coin. Policies that put US food production on more sustainable footing can help aid in public efforts to address the myriad crises confronting both the food and health systems.

The $64 million question. Invest in good teaching

University of Minnesota School of Public health, USA.

Mercury from chlor-alkali plants: measured concentrations in food product sugar

Mercury cell chlor-alkali products are used to produce thousands of other products including food ingredients such as citric acid, sodium benzoate, and high fructose corn syrup. High fructose corn syrup is used in food products to enhance shelf life. A pilot study was conducted to determine if high fructose corn syrup contains mercury, a toxic metal historically used as an anti-microbial. High fructose corn syrup samples were collected from three different manufacturers and analyzed for total mercury. The samples were found to contain levels of mercury ranging from below a detection limit of 0.005 to 0.570 micrograms mercury per gram of high fructose corn syrup. Average daily consumption of high fructose corn syrup is about 50 grams per person in the United States. With respect to total mercury exposure, it may be necessary to account for this source of mercury in the diet of children and sensitive populations.

The role of the environment in pediatric practice in Minnesota: attitudes, beliefs, and practices

Pediatricians can help limit children's exposures to environmental hazards, but few studies have assessed their comfort with discussing and dealing with environmental health issues. We surveyed the membership of the Minnesota Chapter of the American Academy of Pediatrics to assess pediatricians' attitudes and beliefs about the effect the environment can have on children's health, and to assess their practices in regard to screening for, diagnosing, and treating illnesses related to environmental exposures. Results showed that Minnesota pediatricians agree that children are suffering from preventable illnesses of environmental origin but feel ill-equipped to educate parents about many common exposures and their consequences. Responses also indicated significant demand for education on the subject and for a referral center that can evaluate patients who may be suffering from environmental exposures.

Public Health Advocate

With antimicrobial resistance mounting, an important public health goal is to preserve therapeutic effectiveness of remaining antimicrobials. To that end, fewer antimicrobials should be used in human medicine and in agriculture. Public health initiatives to reduce antimicrobial overuse could benefit from concurrent collection of agricultural usage data; they could aid scientific understanding of the resistance problem and confirm the efficacy of interventions. Data collection in this context should be a priority. However, usage data are nonessential to achieving the public health goal. U.S. regulation of agricultural antimicrobials today is very reliant on risk assessment. While more data can be useful for use in risk assessment, microbial risk assessment itself may not be well suited to the purpose of reducing antimicrobial overuse. Among other recognized shortcomings, current microbial risk assessment models typically fail to account for the essential ecological nature of antimicrobial resistance. This makes it inadequate for fully characterizing the human health or ecological risks of animal antimicrobials. European success at phasing out unnecessary antimicrobial usage in agriculture, on the other hand, has derived from decisions based on public health concerns and political will, and not on the collection of usage data or on the successful completion of a risk assessment.

Vinyl chloride: a case study of data suppression and misrepresentation

When the U.S. Environmental Protection Agency (EPA) finalized its 2000 update of the toxicological effects of vinyl chloride (VC), it was concerned with two issues: the classification of VC as a carcinogen and the numerical estimate of its potency. In this commentary we describe how the U.S. EPA review of VC toxicology, which was drafted with substantial input from the chemical industry, weakened safeguards on both points. First, the assessment down-plays risks from all cancer sites other than the liver. Second, the estimate of cancer potency was reduced 10-fold from values previously used for environmental decision making, a finding that reduces the cost and extent of pollution reduction and cleanup measures. We suggest that this assessment reflects discredited scientific practices and recommend that the U.S. EPA reverse its trend toward ever-increasing collaborations with the regulated industries when generating scientific reviews and risk assessments.

Addressing externalities from swine production to reduce public health and environmental impacts

Animal agriculture in the United States for the most part has industrialized, with negative consequences for air and water quality and antibiotic use. We consider health and environmental impacts of current US swine production and give an overview of current federal, state, and local strategies being used to address them.

In harm's way: toxic threats to child development

Developmental disabilities result from complex interactions of genetic, toxicologic (chemical), and social factors. Among these various causes, toxicologic exposures deserve special scrutiny because they are readily preventable. This article provides an introduction to some of the literature addressing the effects of these toxicologic exposures on the developing brain. This body of research demonstrates cause for serious concern that commonly encountered household and environmental chemicals contribute to developmental disabilities. The developing brain is uniquely susceptible to permanent impairment by exposure to environmental substances during time windows of vulnerability. Lead, mercury, and polychlorinated biphenyls (PCBs) have been extensively studied and found to impair development at levels of exposure currently experienced by significant portions of the general population. High-dose exposures to each of these chemicals cause catastrophic developmental effects. More recent research has revealed toxicity at progressively lower exposures, illustrating a "declining threshold of harm" commonly observed with improved understanding of developmental toxicants. For lead, mercury, and PCBs, recent studies reveal that background-population exposures contribute to a wide variety of problems, including impairments in attention, memory, learning, social behavior, and IQ. Unfortunately, for most chemicals there is little data with which to evaluate potential risks to neurodevelopment. Among the 3000 chemicals produced in highest volume (over 1 million lbs/yr), only 12 have been adequately tested for their effects on the developing brain. This is a matter of concern because the fetus and child are exposed to untold numbers, quantities, and combinations of substances whose safety has not been established. Child development can be better protected by more precautionary regulation of household and environmental chemicals. Meanwhile, health care providers and parents can play an important role in reducing exposures to a wide variety of known and suspected neurodevelopmental toxicants that are widely present in consumer products, food, the home, and wider community.

Testing methods for developmental neurotoxicity of environmental chemicals

Human brain development is slow and delicate, involving many unique, though interrelated, cellular events. The fetus and child are often more susceptible to chemical toxins that alter the structure and/or function of the brain, although susceptibility varies for individual neurotoxicants. Early exposure to neurotoxins has been implicated in neurological diseases and mental retardation. Pesticide exposures pose a particular concern since many are designed to be neurotoxic to pests and can also affect humans. Acknowledging the potential for vulnerability of the developing brain, EPA recently began to "call in" data on developmental neurotoxicity (DNT) from manufacturers of pesticides already registered and considered to be neurotoxic-around 140 pesticides. Chemicals are to be tested following the DNT testing guideline (OPPTS 870.6300). This paper assesses whether tests performed according to this guideline can effectively identify developmental neurotoxicants. We found the testing guideline deficient in several respects, including: It is not always triggered appropriately within the current tiered system for testing; It does not expose developing animals during all critical periods of vulnerability; It does not assess effects that may become evident later in life; It does not include methodology for consideration of pharmacokinetic variables; Methodology for assessment of neurobehavioral, neuropathological, and morphometry is highly variable; Testing of neurochemical changes is limited and not always required. We propose modifications to the EPA testing guideline that would improve its adequacy for assessing and predicting risks to infants and children. This paper emphasizes that deficiencies in the testing methodology for developmental neurotoxicants represent a significant gap and increase the uncertainty in the establishment of safe levels of exposure to developing individuals.

Assessment of the U.S. Environmental Protection Agency methods for identification of hazards to developing organisms, Part I: The reproduction and fertility testing guidelines

BACKGROUND

Successful reproduction depends on the coordination of many processes, particularly the normal development and subsequent maturation of the sexual organs. The Food Quality Protection Act of 1996 mandates that the U.S. Environmental Protection Agency must protect infants and children from the effects of toxins, including those that affect the reproductive system. Therefore, the Agency finds itself at a critical juncture to make sure that the methods it requires for toxicity testing, the Health Effects Test Guidelines or Series 870 Guidelines, are adequate to determine possible toxicity to children.

METHODS AND RESULTS

We found that two testing protocols included in the core guidelines assess toxicological effects on developing animals. This article aims to provide a detailed analysis of the protocols included in the Reproduction and Fertility Effects Test Guideline. An accompanying article assesses the Developmental Toxicity Testing Guideline. We conducted this analysis on the basis of whether the test would yield the information needed to adequately determine risk to infants and children.

CONCLUSIONS

Our analysis concludes that given the limitations inherent in testing for reproduction and fertility effects during development, it is necessary to include a safety factor during risk assessment of chemicals. This action will fulfill the mandate expressed in the FQPA to protect infants and children from environmental hazards.

Assessment of the U.S. Environmental Protection Agency methods for identification of hazards to developing organisms, Part II: The developmental toxicity testing guideline

BACKGROUND

The effects of toxins on developing animals depend not only on the nature of the chemical but also on the timing of exposure and assessment of outcomes. This complicates the task of regulatory agencies such as the U.S. Environmental Protection Agency (EPA), which must comply with the 1996 Food Quality Protection Act to ensure that their standards and policies protect infants and children from environmental toxins. For this task, the Agency relies heavily on scientific data obtained by manufacturers of industrial chemicals and pesticides following protocols collected under EPA's Health Effects Test Guidelines.

METHODS AND RESULTS

This article reviews the protocols included in the EPA guidelines to assess developmental toxicity, which are required for food-use pesticides under the core testing battery. We reviewed these protocols on the basis of their adequacy for identifying hazards to infants and children. Our analysis found limitations in the protocols that hinder their potential for identifying developmental hazards.

CONCLUSIONS

Methods that the EPA currently depends upon to identify developmental toxicity of chemicals have limitations that impede obtaining complete and reliable data on which to base regulatory decisions that protect children. Other methodological approaches need to be explored as alternatives or supplements to the current protocols. Until more accurate testing protocols become available, it may well be necessary under existing laws to employ safety factors that are more protective of the health of children at all stages of development.