Seafood is the most important dietary source of the functionally essential omega-3 fatty acid, docosahexaenoic acid (DHA), which is required for normal brain development and heart health. Consequently, seafood intake during pregnancy and lactation should be encouraged to provide for optimal fetal and neonatal development. In an effort to limit exposure to mercury, the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) issued guidance to pregnant and lactating women and small children. The result of this advice was that consumers became unsure of the benefits, were confused about the risks of consuming seafood during pregnancy and breastfeeding, and reduced their consumption of seafood.
Recently, a paradigm shift has occurred, starting with the release of the National Academy of Sciences’ Institute of Medicine (IOM) 2006 report titled “Seafood Choices: Balancing Benefits and Risks.” The report stated, “A better way is needed to characterize the risks combined with the benefits analysis.” In response to the IOM report and to emerging science published subsequent to release of the advice, the FDA released a peer-reviewed draft report in January 2009 on the net effect of eating fish on brain development and heart health (http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/FoodbornePathogensContaminants/Methylmercury/ucm088794.htm).
The draft report is the first in a new type of assessment that weighs the concerns and the benefits of a food for public health. It stated, “The methodology used for this quantitative assessment is novel for the FDA in that rather than attempting to quantify risk resulting from the presence of a particular hazard in a food, it seeks to balance that risk and the benefit from consumption of the food in the same quantitative analysis.” The report also declared, “The risk and benefit assessment provides further scientific information about the likelihood and magnitude of both a beneficial net effect and an adverse net effect at current levels of commercial fish consumption and exposure to methylmercury through fish consumption in the United States.” The draft report aims to help the consumer understand the overall risk of eating fish compared to the risk of not eating fish.
The FDA observed that when women eat a variety of commercial fish, the benefits outweigh the adverse effects of methylmercury at every percentile of fish consumption and corresponding methylmercury exposure. In fact, the assessment stated, “benefits tend to increase as both fish consumption and exposure to methylmercury increase.” The report stated, “For pregnant moms, results show eating fish has a 99.9 percent likelihood of a modest net benefit for verbal development of their babies, and a 0.1 percent likelihood of modest risk. The confidence intervals surrounding these estimates include a small possibility of no adverse effect for anyone but also a small possibility of an adverse effect through 10 percent of the population.”
Why Pregnant Women Need Fish
The 2004 FDA/EPA guidance on seafood consumption in pregnancy (http://www.cfsan.fda.gov/~dms/admehg3.html) recommended that pregnant women, women who want to become pregnant, women who are lactating, and young children should limit seafood consumption to no more than 50 g/day (or two 6-oz servings/week). The document, titled “What You Need to Know about Mercury in Fish and Shellfish,” stated the nutritional benefits of seafood consumption, including:
• fish and shellfish consumption are part of a healthy diet,
• fish and shellfish are an important source of high-quality protein and other essential nutrients,
• fish and shellfish contain beneficial omega-3 fatty acids, and
• fish and shellfish are low in saturated fat.
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The FDA/EPA guidance acknowledged that fish and shellfish are an important part of a well-balanced diet, particularly heart health and a child’s proper development and growth. Recognizing the scientific uncertainty and population-specific nature of long-term neurological effects of methylmercury on the developing fetus, the guidance concluded that for most people the risk from methylmercury through eating fish and shellfish is not a health concern. However, the effect of the message from FDA can best be described by the old axiom, “One had better be safe than sorry.” Although the guidance encourages fish consumption, it has been largely interpreted as a “warning” to avoid or dramatically limit fish during pregnancy. Additionally, there is a “spillover” effect, which means the guidance is reaching individuals outside the targeted area. The FDA/EPA guidance is an example of good intentions with unintended consequences when targeted, risk-based information is released to the public at-large.
The Maternal Nutrition Group (MNG, http://brainybabieshealthykids.org/blog/?m=200710) examined research on the effects of fish consumption on fetal cognitive development and on obstetrical outcomes, particularly birth weight and gestational length. Effects of fish on cognitive development became of real interest when the data from the Faroe Islands study (Grandjean et al., 1997) suggested that there were subtle neurological effects associated with decreased fetal cognitive performance among children born to women who consumed seafood, including large portions of pilot whale meat. This study was in contrast to the Seychelles Child Development study (Myers et al., 2007) on 799 mother-child dyads. The mothers in the Seychelles study consumed an average of 22 oz of ocean fish per week. The children born to these mothers were assessed at 6, 19, 66 (5.5 years), and 107 months (9 years) of age. No adverse effects on cognitive development in the Seychelles children have been reported on 5-year-olds (Davidson et al., 1998). Among the 9-year-olds, methylmercury had only one negative association as defined by the peg board test using the non-dominant hand (Myers et al., 2004). Two positive associations for methylmercury consumption were related to preschool language scale at 5 years and the teacher rating scale for cognitive development at 9 years. Reasons for the positive skills were hypothesized to be omega-3 fatty acids, iodine, and/or selenium contributed by the ocean fish.
Presence of selenium could explain the difference in the Faroe Islands study and the Seychelles study. Selenium is abundant in ocean fish but not pilot whale meat, and this element has been documented to mitigate the effects of methylmercury in ocean fish, presumably by decreasing absorption from the gastrointestinal tract and decreasing absorption across the blood-brain barrier (Kaneko and Ralston, 2007; Ralston et al., 2007).
Because it most closely reflects the North American seafood consumption patterns, the most important study reviewed by the MNG was a longitudinal study called the ALSPAC (Avon Longitudinal Study on Parents and Children) study that included 11,875 pregnant mother-child dyads (Hibbeln et al., 2007). The mothers-to-be completed a food frequency questionnaire at 32 weeks of gestation and at several other occasions throughout pregnancy and the post-partum period. The food frequency instrument was validated by red blood cell fatty acid analysis. Statistical analyses controlled for 28 variables to determine the effect of fish intake on the development scales used in the study. Measurements were made at 6, 18 (1.5 years), 30 (2.5 years), 42 (3.5 years), and 81 (6.75 years) months of age. Fish intake for the women was defined as 1) none; 2) 1–340 g/week; or 3) > 340 g (12 oz)/week. Results consistently showed that those with less than 340 g/week intake of seafood did poorer on all measures of cognitive development (i.e., verbal IQ, prosocial behavior, fine motor skills, and communication skills).
High fish consumption was associated with a slight (94 g) decrease in birth weight (Oken et al., 2004) in a Harvard University cohort study of 341 mother-child dyads. However, these infants showed improved cognitive development (Oken et al., 2005). A follow-up study demonstrated that the babies from mothers with the highest intake of fish had the highest IQ scores using Peabody Picture Test and a wide range assessment of visual motor ability at 3 years of age (Oken et al., 2008). Results were especially profound among the 12% of women who consumed more than 2 servings of fish per week.
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Fish oil supplementation trials were conducted across Europe by Olsen et al. (2000) with four prophylactic trials consisting of 232 women with previous pre-term delivery, 280 women with previous intrauterine growth failure, 386 women with previous pregnancy induced hypertension, and 579 women with current twin pregnancies, and two therapeutic trials with 79 women with impending pre-eclampsia and 83 women with suspected intrauterine growth failure. While the amount of fish oil administered was large, the result was significant reduction in recurrence of pre-term delivery (33% in the control group vs 21% in the group under fish oil treatment). Accompanying these results were an 8.5 day increase in gestational length and 209 g increase in birth weight in women who previously delivered pre-term. A subsequent trial (Knudsen et al., 2006) to establish the efficacious level of fish oil to decrease pre-term labor or increase birth weight was unsuccessful. Meta analyses with DHA and/or fish oil supplements were equivocal (Szajewska et al., 2006). However, some of the studies included were underpowered to detect differences, and there was a large variation in dose and form of supplementation.
Since fish contain methylmercury, some suggest that pregnant women might obtain their DHA from fish oil or algal oil sources. Consequently, Anderson et al. (2009) designed an intervention study to examine the effect of nutrition education vs supplements on gestational length. The control group received no supplements while a second group received 300 mg DHA, a third group received 600 mg DHA, and a fourth group received nutrition education to increase DHA intake by 300 mg/day by eating two servings of fish per week and/ or DHA-rich foods. The results show that nutrition education increased gestational length by 4.5 days compared to 4 days for those taking 600 mg DHA vs the control group. Nutrition education was as effective as providing twice as much DHA in supplement form.
After examination of the existing data, the MNG proposed that the risk of not eating fish outweighed theoretical risks of eating fish during pregnancy and that the FDA/EPA intent to limit consumption of seafood during pregnancy could result in inadequate intake of the essential nutrient omega-3 DHA. The MNG recommended that:
• Women who want to become pregnant, are pregnant, or are breastfeeding should consume at least 12 oz of seafood per week.
• Long-chain omega-3 fatty acids (DHA and EPA) enhance visual, cognitive, and motor skills and behavioral development in children and may reduce pre-term labor.
• The recommended consumption level will correct for a nutritional deficiency.
• The presence of selenium may mitigate the effects of methylmercury in fish.
The MNG concluded, “Consumption of whole fish rather than fish oil supplements is the best public health approach. Whole fish consumption rather than the taking of fish oil supplements is more frequently linked to reduction in pre-term labor and provide lean protein and other beneficial nutrients that are not completely understood.”
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Further support for the MNG position comes from several points of view. The U.S. National Oceanic & Atmospheric Administration (NOAA) released a Fact Sheet at the 2008 International Boston Seafood Show that stated, “As an agency we have concluded that the mercury issue has been overstated. Recent scientific understandings are indicating that the public health concerns regarding mercury in fish are not as profound as commonly perceived and can result in unintended consequences by scaring people away from a healthy and nutritious foodstuff” (Garrett and Lowery, 2008). In 2004, the United Kingdom Scientific Council on Nutrition (SACN) recommended consumption of 2–3 servings of oily fish per week during pregnancy, including two 140 g portions of fresh tuna per week or four 140 g of canned tuna. In 2006, the National Academies Institute of Medicine (IOM) published “Seafood Choices: Balancing Benefits and Risks.” This important report called for a “decision pathway” for pregnant women, women who wish to become pregnant, and those who are breastfeeding, noting that they may benefit from consuming seafood with higher DHA and EPA levels. Consumption of 12 oz of fish per week, which could include 6 oz of albacore tuna, was recommended. Further, the IOM acknowledged differences in the way consumers receive messages and act on them. “One size fits all” messaging does not meet the needs of diverse audiences. Tailored messages are needed to improve effectiveness. The IOM recommended:
• Federal agencies should advise the public that seafood is part of a healthy diet.
• Federal agencies should encourage pregnant women or those who may become pregnant to include seafood in their diets (within federal advisories for specific seafood types and state advisories for locally caught fish).
• Appropriate federal agencies should develop easy-to-use, understandable tools for consumers which consolidate risks and benefits to allow informed choices.
• New tools, apart from traditional safety assessments, should be developed such as consumerbased risk-benefit analysis.
• Messages need to be tested for spillover effects.
Translating scientific findings into a language easily understood by consumers, and one they will follow, is a tough task. Sometimes talking directly to consumers helps to understand their thinking when making decisions in support of their health. Following are four basic tenets of risk-benefit communication developed at the Center for Consumer Research at UC-Davis:
1. Communication is an ongoing process, not a onetime event. Communication must go on year after year because there are new consumers to address who didn’t get the message the first time.
2. Be sure the information is evidence-based and gives consumers clear understanding of the risk and benefits in the language and literacy level they understand.
3. Empower consumers to make an informed decision, so they hear the information, process it, and confidently apply it to their own situation.
4. Meet the unique needs and knowledge of the target audience to make a health-promoting decision.
Once these aspects of communication are accomplished, it is crucial that the message remains consistent. For example, the FDA/EPA guidance and the USDA MyPyramid (http://mypyramid.gov/) recommendations should be the same. Currently, the FDA/EPA guidance recommends eating up to 12 oz or 2 fish meals per week. One serving is defined as 6 oz. Meanwhile, MyPyramid has no clear recommendation for seafood other than to choose it more often as a lean protein. One serving of fish is defined as 2–3 ounces. Specifying a precise amount may be helpful to the consumer. The three agencies do uniformly suggest that consumers check local advisories for regional information relative to mercury and safety of eating those fish. The recommendations in each case go on to specify shark, swordfish, mackerel, and tilefish as the ones to avoid if you are pregnant or breastfeeding. While consumers recognize shark, swordfish, and mackerel, few know what tilefish is. The message, therefore, is not well understood.
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Recent consumer research provides insight as to what is needed for clear messages. Vardeman and Aldoory (2008) at the University of Maryland have done focus groups on consumer attitudes toward fish. These researchers conducted six focus groups in three states on the East Coast with 59 women of whom eight were pregnant or had children. All were of childbearing age. Ethnic composition was 31 white, non-Hispanic; 25 black; 2 Hispanic; and 1 Asian. Half had a college degree. Participants were asked to read three news clips describing the FDA/EPA guidance, and then they were asked to react as to what they believed or how they would react as consumers.
The participants were very confused and found the information contradictory. Limiting consumption was not a category to which they could relate. In general, many expressed anger, irritation, or annoyance that they were not receiving truthful information from the government or the seafood industry. Some took the avoidance message seriously and said they would switch to canned light tuna and minimize the albacore. Some balanced the consumption of fish with other health risks. They did understand the benefits but were concerned about the risks (i.e., mercury issues). Overall, they felt overwhelmed by the volume of food/ health information they receive in the media. When pregnant participants were faced with contradictory information, their role as protectors became priority, and health benefits from eating fish were less important than potential risks of consuming mercury.
As food professionals working in industry and the government, we need to move to greater consensus about the total risk of eating fish to the total risk of not eating fish. We need to reevaluate the advisories to communicate the net effect (benefit minus risk) which, in the case of seafood, equals a benefit. And, we need to continue to evaluate the emerging data, especially the role of selenium in minimizing risk from mercury (Ralston et al., 2008).
Pilot whale was an influencing factor in preparing the FDA/EPA guidance because it is high in mercury though low in selenium. However, pilot whale is not a part of the American diet, so considering it for U.S. guidance should be questioned.
Messages that Resonate with Consumers
Americans are connecting the foods they eat with their personal health. Statistics from the International Food Information Council (IFIC, http://www.ific.org/research/funcfoodsres07.cfm) show that 84% of Americans are somewhat interested in learning more about functional foods (i.e., foods that deliver health benefits as well as good nutrition). The vast majority of Americans that IFIC interviewed believe that they have at least moderate control over their health, and three-quarters believe that control is through food and nutrition.
Heart and circulatory health issues top the list of health concerns (Table 1). Americans look to functional foods to give them benefits beyond basic nutrition, and seafood is second on that list (Table 2). Omega-3 fatty acids from seafood are quickly recognized for reduced risk of heart disease. Not quite half of those interviewed are already consuming omega-3 sources for that benefit. IFIC’s interaction with consumers reveals that there is no single or clear recognized authority on the health benefits of good nutrition, so many won’t make a positive dietary change. Regarding seafood, the positive messages reach consumers as often as the negative (Hicks et al., 2007). IFIC recommends nutrition and health messages with “IMPACT,” its own creative acronym for communicating with consumers. To make their points, messages should be:
• Positive and Personalized
• Context and Choices
• Tailored and Tested by Science
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In addition, IFIC has developed a more formal seven guiding principles as part of its “Guidelines for Communicating the Emerging Science of Dietary Components for Health” through a partnership with the Institute of Food Technologists (IFT). These guidelines may be found at http://www.ific.org/nutrition/functional/guidelines. Principle 2 recommends clearly conveying the differences between emerging and consensus science. Emerging science is proving the mitigating effects of selenium against methylmercury, but consumers have limited access to this kind of positive information, not to mention understanding how selenium fits into the risk-benefit picture.
The past several years have brought about a paradigm shift in the role of seafood in health in terms of the risk of not eating seafood, especially during pregnancy and lactation. The MNG, IOM, and FDA have examined the recent science and the current issues arising from traditional methods of describing and communicating health benefits and risks. The consumer must be provided with clear information with which to make health-related decisions. The latest approach is communicating “net benefit” when the benefits exceed risks (or net risks if the benefits are low or unproven). Since the preponderance of the evidence supports a net benefit of seafood for fetal and neonatal neurocognitive development, women of child bearing age, women who are nursing or pregnant, the unborn and newborn, and young children should be encouraged to consume two meals of seafood (preferably fatty ocean fish) per week, avoiding only those few species found to be highest in methylmercury.
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