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5 Nutrition-Related Health Risks and Outcomes of WIC-Eligible Populations INTRODUCTION A comprehensive examination of nutrition-related factors relevant to proposing the WIC food packages must include consideration of a number of health risks. This chapter presents the epidemiological evidence that the Committee found to be relevant in applying the findings in Chapters 3 and 4. In particular, the Committee considered risks related to weight status (as discussed in numerous places throughout this report); micronutrients of special concern during reproduction and early childhood; food allergies; and selected environmental risks to the health of women, infants, and children. MATERNAL NUTRITION-RELATED HEALTH RISKS AND OUTCOMES Weight Status Starting at a young age, women often struggle to maintain a healthy body weight, which is defined as a body mass index (BMI = weight kg/height m2) in the range of 18.5 to 25.0. The growing rates of overweight and obesity among female adolescents and women, particularly those who are disadvantaged, have been well-documented and are of national concern (Flegal et al, 1998). Maternal weight status before, during, and after pregnancy has implications for reproductive health and infant outcomes, as well as chronic disease risk in the near- and long- term as described in previous reports from the Institute of Medicine (NRC, 1989a; IOM, 1990). Prepregnancy obesity has been associated with menstrual irregularities (Balen, et al, 1995), infertility problems (Zaadstra et al., 1993; Balen, et al, 1995), pregnancy complications (Naeye, 1990; Solomon et al., 1997; Cnattingius et al., 1998; Thadhani et al., 1999), adverse birth outcomes (Shaw et al., 1996, 2000), and postpartum anemia (Bodnar et al., 2001, 2002). Obesity is thought to develop from a complex interaction of genetic and environmental factors (NRC, 1989a; NIH, 1998), but scientific knowledge of how and why obesity develops is far from complete. However, the ultimate cause of obesity is positive energy balance. Although the overall WIC program is able to promote healthy body weight through many mechanisms such as 5-1
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5-2 PROPOSED CRITERIA FOR SELECTING THE WIC FOOD PACKAGES encouraging daily physical activity at an appropriate level for each individual, food energy intake is the factor that can reasonably be addressed by the WIC food packages. Low pregravid weight, variably defined, also has consequences of concern, including intrauterine growth retardation, small gestational age, and preterm birth (Wen et al., 1990; Abrams and Newman, 1991; Siega-Riz et al., 1996; Kramer et al., 1999). Therefore, women who are underweight prior to pregnancy continue to be of high priority for targeted nutrition interventions. Pregnancy Weight Gain and Pregnancy-Related Weight Retention In 1990, the IOM recommended ranges for pregnancy weight gain within categories of prepregnancy BMI (IOM, 1990). The current pregnancy weight gain recommendations have evolved from decades of observations made regarding birth outcomes; maintaining weight gains within the optimal range results in better overall infant outcomes (Siega-Riz et al., 1996; Abrams et al., 2000; Schieve et al., 2000). However, when weight gains exceed the upper limits recommended by the IOM, poor birth outcomes are observed at a higher frequency and maternal and fetal complications are increased (Witter et al., 1995; Johnson and Yancey, 1996). Since release of the IOM report, several studies have examined the pattern of pregnancy weight gain compared with the recommendations. These studies show that most women do not follow the recommendations; in fact, many women gain more than recommended (Siega-Riz et al., 1994; Caulfield et al., 1996; Carmichael et al., 1997; Schieve et al., 1998; Cogswell et al., 1999). Pregnancy-related weight retention has long-term implications and is a potential pathway leading to increased adiposity that persists beyond the reproductive years into menopause. Pregnancy weight gain above the recommended range is associated with post-pregnancy weight retention and increased adiposity (Gunderson and Abrams, 2000; Olson et al., 2003), particularly in women with lower incomes (Olson et al., 2003). Among women with high pre-pregnancy BMI, pregnancy-related weight retention is greatest, despite lower pregnancy weight gains (Gunderson et al., 2001). Maternal Iron Deficiency Reduction of iron deficiency among women of childbearing age is a goal of Healthy People 2010 (DHHS, 2000a). The target for the reduction of iron deficiency1 by 2010 is a prevalence of no more than 7 percent in non-pregnant females ages 12 through 49 years (Goal 19-12c) (DHHS, 2000c). A related goal is the reduction of anemia2 among low-income pregnant females in the third trimester to a prevalence of no more than 20 percent (Goal 19-13) (DHHS, 2000c). Laboratory data from NHANES 1999-2000 indicates that the prevalence of iron deficiency3 was nine percent among adolescent females aged 12 through 15 years; 16 percent among adolescent females aged 16 through 19 years; and 12 percent among adult females aged 20 1Laboratory tests used to define iron deficiency are serum ferritin, erythrocyte protoporphyrin, and transferrin saturation. Nonpregnant females ages 12 to 49 years were considered iron-deficient if two or more of the laboratory values were abnormal; notice that anemia was excluded from the criteria (DHHS, 2000d). 2Laboratory values used to define anemia were hemoglobin concentrations less than 11.0 g/dL (DHHS, 2000d). 3Laboratory tests used to define iron deficiency were abnormal values for at least two of the following three indicators: serum ferritin, transferrin saturation, and free erythrocyte protoporphyrin. Thresholds for the laboratory values were defined by NHANES III (Looker et al., 1997).
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NUTRITION-RELATED H EALTH RISKS AND OUTCOMES IN WIC-ELIGIBLE POPULATIONS 5-3 through 49 years (CDC, 2002). The prevalence of iron deficiency3 was approximately two times higher among non-Hispanic black and Mexican-American females (19 to 22 percent) than among non-Hispanic white females (10 percent). In 1996, the prevalence of anemia4 among low- income, pregnant women enrolled in public health programs was 8, 12, and 29 percent in the first, second, and third trimesters, respectively (CDC, 1998). Recently published analyses of data from NHANES 1988-1994 revealed that even though the prevalence of iron deficiency5 was 4.7 percent among adolescents (ages 12-16 years), the rates of iron deficiency were higher among subgroups who were female, overweight, Mexican American, or from families with incomes below the poverty level (Nead et al., 2004). Iron deficiency remains prevalent among pregnant women in the U.S. because of low iron stores prior to pregnancy, high iron demands of the pregnancy state itself, and poor compliance with iron supplementation (Suitor and Gardner,1990; Looker et al., 1997; IOM, 2001). Anemia6 has been weakly but consistently associated with increased risk of preterm delivery (Fedrick and Anderson, 1976; Kaltreider et al., 1980; Murphy et al., 1986; Klebanoff et al., 1989, 1991; Siega-Riz et al., 1998). Iron-deficiency anemia7 in the first trimester also has been associated with preterm delivery and low birth weight (Scholl et al., 1992). Among low-income, postpartum women, prevalence of iron-deficiency anemia8 ranges from 19 to 33 percent (Bodnar et al., 2001; Swensen et al., 2001). The health effects of postpartum anemia have not been well studied but are assumed to be similar to the general effects of anemia such as fatigue, decreased work performance, and decreased exercise tolerance (Li et al., 1994; Cook, 1994; McKenzie, 2004). Postpartum anemia may lead to compromised iron status in subsequent pregnancies (Allen, 2000). Previous studies have indicated that the WIC Program may contribute to the adequacy of iron intake among low-income women (Rush et al., 1988a; Pehrsson et al., 2001). Folate and Birth Defects Well-designed studies have documented the relationship between low maternal folate stores and birth defects such as the neural tube defects of spina bifida and anencephaly (Daly et al., 1995). In response to this information, the RDA for folate for women of reproductive age was increased from 150-180 mcg (NRC, 1989b) to 400 mcg (IOM, 1998), an increase of over 100 percent. Over the last decade, a period of folate fortification of grain products, NHANES data have demonstrated increases in median serum folate levels ranging from 155 to 170 percent and in median red blood cell folate from 58 to 73 percent across different racial/ethnic groups (CDC, 2000). Concurrently the prevalence of neural tube defects has declined by 19 to 23 4 Laboratory tests used to define anemia were abnormal hematocrit and/or hemoglobin values. 5 Laboratory tests used to define iron deficiency were transferrin saturation, free erythrocyte protoporphyrin levels, and serum ferritin levels. Individuals, ages 2 to 16 years of age for the complete dataset, were considered iron-deficient if two of the laboratory values were abnormal for age and gender. 6 Laboratory tests used to define anemia were abnormal hematocrit or hemoglobin values. Cut points for the laboratory values were gestational age-specific (CDC, 1989). 7 Laboratory tests used to define iron-deficiency anemia were abnormal hematocrit/hemoglobin values with serum ferritin concentrations less than 12 mcg/L. 8 Laboratory tests used to define anemia were serum ferritin values, hemoglobin values or, in some cases, hematocrit values converted to hemoglobin values. Reference ranges for laboratory values were defined by CDC (1998) and values were adjusted for smoking and altitude of the clinic as recommended (CDC, 1998).
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5-4 PROPOSED CRITERIA FOR SELECTING THE WIC FOOD PACKAGES percent (Honein et al., 2001; Mathews et al., 2002; Williams et al., 2002; CDC, 2004)-- somewhat less than the expected decline of 50 percent based on earlier estimates of folate intake that would be achieved as a result of the folate fortification initiative (CDC, 1992, 2004). Moreover, disparities persist and many women appear unaware of the connection of folate intake to birth outcomes. The latest March of Dimes Gallop Poll indicates that only 30 percent of women of childbearing age report taking a multivitamin containing folate on a regular basis and this percentage has not changed in the past few years despite public health messages (March of Dimes Birth Defects Foundation, 2003). Thus, women of reproductive age may fail to take a daily multivitamin supplement or other measures that may contribute to optimal folate status. Nutrients and Improved Birth Outcomes Preterm birth is a major contributor to infant mortality. Several nutrients have been implicated in the etiology of preterm birth. Evidence from observational studies suggests a role of low vitamin C intake in predisposing a pregnancy to preterm delivery through premature rupture of the membranes (Wideman et al., 1964; Casanueva et al., 1991; Siega-Riz et al., 2003). Adjusting for a number of nutritional and other risk factors, low folate intake was moderately associated with preterm delivery (Scholl, 1996; Siega-Riz and Laraia, 2004). Low levels of antioxidants such as vitamins A, C, and E 9 have been implicated in the etiology of preeclampsia and are now being tested in randomized studies (Roberts et al., 2003). Maternal Vitamin D Data for vitamin D intakes were unavailable in the original CSFII data set, and therefore could not be directly examined with the analytic approach used in Chapter 3. However, Moore et al. (2004) recently constructed a database for vitamin D intakes based on the CSFII and found that mean intakes from food sources were below the AI for nonpregnant, nonbreastfeeding adolescents (14 through 18 years of age) and for adult women of reproductive age (19 through 30 years or 31 through 50 years of age). There is some uncertainty about the adequacy of vitamin D intakes for adolescents and women (IOM, 2000a). This uncertainty is greater for women during pregnancy and lactation as these women were not included in the analyses by Moore et al. (2004). Vitamin D is a crucial nutrient in developing and maintaining bone health and it has been identified as a nutrient of public heath importance for all women (Calvo and Whiting, 2003). NUTRITION-RELATED HEALTH RISKS AND OUTCOMES IN INFANTS AND CHILDREN Weight Status Currently in the U.S., over-consumption can be a concern if manifest in signs and symptoms of macronutrient- or micronutrient-specific toxicities, or by contributing to short- or long-term risk of certain chronic diseases (Wardley et al., 1997). Both the National Health and Nutrition Examination Survey (NHANES) and Pediatric Nutrition Surveillance System have documented an increase in the prevalence of overweight among preschool children (Mei et al., 1998; Ogden et al., 2002). An increase in overweight in even the youngest children is of concern, 9 Low values have been reported in the general population for circulating vitamin E (-tocopherol) (Ford and Sowell, 1999).
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NUTRITION-RELATED H EALTH RISKS AND OUTCOMES IN WIC-ELIGIBLE POPULATIONS 5-5 not only because of its association with later overweight, but also because of associated short- term morbidity. For example, both overweight status at an early age and a high rate of increase in BMI appear to increase the risk of asthma during childhood (Gold et al, 2003). Childhood overweight is also associated with a number of comorbidities such as hyperlipidemia, hypertension, and type 2 diabetes (Must and Strauss, 1999; Dietz, 2001) as well as with higher morbidity and mortality in adulthood (Dietz, 1998a, 1998b). Infancy may be a critical period for the development of overweight in childhood and its long- term health consequences. Early catch-up growth among children born small has been strongly associated with higher BMI, especially central obesity in early childhood (Whitaker et al., 1997; Ong et al., 2000), and with adult systolic blood pressure (Whitaker et al., 1997; Law et al., 2002). Furthermore, rapid weight gain from birth to four months of age has been associated with overweight at age seven years and in early adulthood (Law et al., 2002; Stettler et al., 2002). Low birth weight, failure to thrive in infants, and underweight in children can be serious problems (AAP, 2004). The prevalence of undernutrition is low in the general U.S. population (Wang, et al., 2002); however, the low-income population (i.e., the WIC-eligible population) may be both most vulnerable to undernutrition and most vulnerable to significant impacts when undernutrition does occur. In order to promote a healthy body weight for each infant and child, the overall energy balance between basal needs, growth, physical activity, and food energy intake must be considered in prescribing an appropriate food package. Thus, flexibility to promote food energy intakes over a healthy range at each age and stage of development should be considered in formulating the food package allowances from which a more specific prescription will be drawn for an individual infant or child. Vitamin D in Bone Health Although it is well known that low levels of vitamin D intake in children result in diminished growth and rickets (Curran et al., 2000), it was not possible for the Committee to directly examine vitamin D intakes for children in the CSFII because intakes of this nutrient were not quantified in the original data set (Tippett and Cypel, 1997). However, Moore et al. (2004) estimated vitamin D intakes for the CSFII participants and reported that mean intakes exceeded the AI for non-breastfeeding children 1 to 8 years of age. This indicates that vitamin D intakes are likely to be adequate among children in these age groups on a population basis. Nevertheless, a possible reemergence of vitamin D deficiency as a public health concern in the United States has been suggested. Vitamin D deficiency has been reported in population subgroups or the whole population in regions with seasonal variation in exposure to sunlight (Daaboul et al, 1997; Lawson and Thomas, 1999; Lawson et al., 1999; Kreiter et al., 2000; Dawodu et al., 2003). For example, a study in African-American breastfed infants and children (up to two years of age) in North Carolina illustrated that infants and children of some ethnic groups might be at higher risk for vitamin D insufficiency than previously assumed (Kreiter et al., 2000). The authors suggested this may be due to low vitamin D intake (Kreiter, et al., 2000). However, other authors have implicated other factors in the possible reemergence of vitamin D inadequacy (Daaboul et al, 1997; Blumsohn, 1999; Zlotkin, 1999; Welch et al., 2000; Seeler, 2001; Shaw and Pal, 2002; Dawodu et al., 2003). Thus, whether inadequate intakes of vitamin D are a public health concern remains controversial. Despite the controversy, a calcium- and vitamin D-rich diet during periods of peak bone mass accretion and having sufficient weight bearing exercise throughout life are the
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5-6 PROPOSED CRITERIA FOR SELECTING THE WIC FOOD PACKAGES most promising interventions to promote bone health at this time (Raisz, 1999; New, 2001; Branca et al., 2001). Iron Deficiency Reduction of iron deficiency among young children is a goal of Healthy People 2010 (DHHS, 2000a). The target for the reduction of iron deficiency 10 by 2010 is a prevalence of no more than 5 percent in children ages 1 through 2 years (Goal 19-12a) and no more than 1 percent in children ages 3 through 4 years (Goal 19-12b) (DHHS, 2000c). Reports demonstrate a decrease in the prevalence of anemia11 in U.S. children since the 1970s (DHHS, 2000c; Sherry et al., 1997, 2001). In 1999 and 2000, the estimated prevalence of iron deficiency12 was 7 percent among toddlers ages 1 through 2 years and 5 percent among 3- through 5-year-olds (CDC, 2002). Recently published analyses of data from NHANES 1998- 1994 revealed that even though the prevalence of iron deficiency13 was only 2.3 percent among children ages 2 through 5 years of age, the rates of iron deficiency were higher among subgroups who were overweight, Mexican American, or from families with incomes below the poverty level (Nead et al., 2004). Differences in the prevalence of iron-deficiency anemia14 among ethnic groups indicate the need to improve iron content and/or bioavailability, especially in diets of low income and minority children (Kwiatkowski et al., 1999). Previous studies have indicated that the WIC program may contribute to the adequacy of iron intake among low-income infants (Miller et al., 1985; Batten et al., 1990; Sherry et al., 2001; Ponza et al., 2004) and children (Brown and Tieman, 1986; Rush et al., 1988b; Rose et al., 1998; Sherry et al., 2001; Siega-Riz et al., 2004). Possible Nutrient Deficiencies in Breastfed Infants Because intake data for breastfed infants could not be included in the analyses in Chapter 3, special attention must be paid to other sources of intake data that include infants solely or partially breastfed. The Feeding Infants and Toddlers Study (FITS) examined nutrient intakes among a combined sample of both breastfed and non-breastfed infants ages 7 through 11 months (Devaney et al., 2004) and found low prevalences of dietary inadequacy for iron (7.5%) and zinc (4.2%), the only two micronutrients with an EAR for this age group. Among WIC participants of the same age, the prevalence of iron inadequacy was only 1 percent (Ponza et al., 2004). For all nutrients with an AI, mean usual intakes for this combined sample of breastfed and non-breastfed 10Laboratory tests used to define iron deficiency are serum ferritin, erythrocyte protoporphyrin, and transferrin saturation. Individuals (children ages 1 through 4 years) were considered iron-deficient if two or more of the laboratory values were abnormal (DHHS, 2000d). 11Laboratory tests used to define anemia were abnormal hematocrit values. Reference ranges for the laboratory values were defined by CDC (1989, 1998). 12Laboratory tests used to define iron-deficiency were abnormal values for at least two of the following three indicators: serum ferritin, transferrin saturation, and free erythrocyte protoporphyrin. Reference ranges for the laboratory values were defined by NHANES III (Looker et al., 1997). 13Laboratory tests used to define iron deficiency were transferrin saturation, free erythrocyte protoporphyrin, and serum ferritin. Individuals, ages 2 through 16 years of age for the complete dataset, were considered iron- deficient if two of the laboratory values were abnormal for age and gender. 14Laboratory tests used to define anemia were hemoglobin values. Reference ranges for laboratory values were defined by CDC (1998). Anemia responded to iron therapy.
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NUTRITION-RELATED H EALTH RISKS AND OUTCOMES IN WIC-ELIGIBLE POPULATIONS 5-7 infants exceeded the AI at both age groups 4 through 6 months and 7 through 11 months, implying a low prevalence of inadequacy. The Committee also considered clinical and analytical data that could suggest nutrient deficiencies in this vulnerable group. From chemical analyses of breast milk at various stages of lactation (Vaughan et al., 1979; Rajalakshmi and Srikantia, 1980; Ohtake and Tamura; 1993), the iron and zinc content is inadequate for infants 7 through 11 months of age (Krebs, 2000; Dewey, 2001; Krebs and Westcott, 2002). Therefore, foods supplying both iron and zinc are needed for 7- through 11-month old breastfed infants. At the present time there are no data to suggest nutrient deficiencies are developing in breastfed infants, with the exception of the continuing problem of iron deficiency and the risk of zinc inadequacy without appropriate complementary foods after six months of age (Skinner et al., 1997; Krebs, 2000; Dewey, 2001; Krebs and Westcott, 2002), and the possibility of vitamin D deficiency in specific populations as noted above. The committee will also consider guidelines for addition of complementary foods (Dewey, 2001; AAP, 2004) in designing the food package for older breastfed infants. FOOD ALLERGIES Food allergy or hypersensitivity is most common from birth to one year of age. About 5 percent of children are affected between birth and four years of age (AAP, 2004). By childhood and adolescence, the prevalence of food allergy declines to 1 to 2 percent. Foods that most commonly cause allergic reactions in children are eggs, cow's milk, soy, wheat, peanuts, tree nuts, fish, and shellfish (Twarog, 1998; AAP, 2004). In infants, 2 to 3 percent develop confirmed sensitivity to cow's milk protein (James and Sampson, 1992; Host, 2002). About 85 percent of those infants develop tolerance to milk products by four years of age (James and Sampson, 1992; Host, 2002). Allergy to soy also diminishes with age whereas allergies to peanuts, tree nuts, fish, and shellfish are generally lifelong (Twarog, 1998; Rudolph and Rudolph, 2003). Specifically, in the U.S., anaphylactic reactions to peanuts and foods containing peanuts in some form account for the largest number of fatal and near-fatal allergic reactions to food (Sampson et al., 1992; Bock et al., 2001; AAP, 2004). ENVIRONMENTAL RISKS IN THE WIC POPULATION Calcium to Mitigate Lead Exposure in Pregnant and Lactating Women People are exposed to lead by breathing air, drinking water, eating food, or swallowing or touching dust or dirt that contains lead (ATSDR, 1999a). Lead is then stored in various body tissues including bone. During pregnancy and lactation, lead ingested by a mother or mobilized from bone can affect lead concentration in breast milk (Ettinger et al., 2004) and fetal (Gonzalez- Cossio et al., 1997; Hernandez-Avila et al., 2003) and infant growth (Sanin et al., 2001). Blood lead concentrations increase in pregnant women in a U-shaped pattern with higher values in the first and third trimesters (Hertz-Picciotto et al., 2000). Multiple factors, such as age, smoking, educational level, ethnic background, breastfeeding, and calcium intake, are associated with the blood lead concentration (Hernandez-Avila et al., 1996). Women breastfeeding more than 30 months over their lifetime, and those with higher dietary calcium intake had lower lead concentrations in their blood compared to women who breastfed for shorter cumulative duration and with lower calcium intakes (Hertz-Picciotto et al., 2000). The calcium intake effect was only
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5-8 PROPOSED CRITERIA FOR SELECTING THE WIC FOOD PACKAGES in the later half of pregnancy, and showed a dose-dependent effect across a range of calcium intakes (from 2.0 g calcium per day) (Hertz-Picciotto et al., 2000). Data from women in Mexico City provide additional information relevant to immigrant populations participating in the WIC program and to women who may have had similar exposures in urban areas in the U.S. Maternal blood lead and umbilical cord blood lead were inversely associated with milk and orange juice intake during pregnancy, controlling for sociodemographic characteristics, lifetime exposure to vehicular traffic, and the use of lead-glazed ceramics (Hernandez-Avila et al., 1997). Among women who participated in a longitudinal, randomized, placebo-controlled, double-blind trial, supplementation of 1.2 g calcium15 was associated with a 15 to 20 percent reduction in blood lead values over the course of lactation (Hernandez-Avila et al., 2003). Thus, from studies investigating a wide range of calcium intakes, adequate calcium intake appears to have the added benefit of decreasing blood lead values in pregnant and lactating women. Dioxins and Dioxin-Like Compounds Dioxins (chlorinated dibenzo-p-dioxins) and dioxin-like compounds (DLC) are low-level environmental contaminants, but their presence in animal feed and the human food supply is widespread (ATSDR, 1999b). DLC have a variety of potential toxic effects including developmental effects in the fetus and infant (ten Tusscher and Koppe, 2004). In the general population, DLC likely contribute to increasing risk for a variety of types of cancer (Kogevinas, 2000, 2001). Exposure to DLC is almost entirely through the food supply, and primarily from consumption of animal fat. In the current WIC food packages, animal fat may be found in milk, cheese, eggs, and tuna. DLC are long-lived, lipophilic compounds and can accumulate in body fat over the lifetime. While improvements in environmental and animal husbandry practices are the long-term solution to DLC contamination, in the short-term, a reduction in consumption of animal fat will reduce exposure to these toxicants (IOM, 2003b). A substantial portion of lifetime exposure to DLC occurs prenatally and through breast milk. Due to the persistence of DLC, decreasing DLC exposure of the women only during pregnancy and lactation is relatively ineffective in lowering the exposure of the fetus or breastfeeding infant. Lowering body burdens in the population requires a reduction in consumption of animal fat throughout the reproductive life of girls and women (ten Tusscher and Koppe, 2004). Recommendations in a recent IOM report (IOM, 2003b) include increased awareness of exposure during early life and efforts to decrease the DLC exposure and lifetime accumulation in girls and young women. It has been proposed that a population-wide reduction in total lifetime body burden could be attained through reductions in the consumption of animal fat during both the pre-reproductive and reproductive life of girls and women (ten Tusscher and Koppe, 2004). This attention to early life DLC exposure in females is intended to reduce risk to the offspring, while continuing to support optimal growth and development of the young (or adolescent) mother and her fetus and to support breastfeeding as the optimal source of nutrition for infants. Additionally, the IOM report specifically recommends increasing the availability of low-fat and non-fat dairy products in federal programs targeted to children over the age of two years (IOM, 2003b). 15 Mean baseline intake of dietary calcium was 1,160 mg per day (+ 761 SD, n=296) for supplement group and 1,137 mg per day (+ 597 SD, n=321) for the placebo group.
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NUTRITION-RELATED H EALTH RISKS AND OUTCOMES IN WIC-ELIGIBLE POPULATIONS 5-9 FDA and EPA Fish Advisories Fish is high in protein and other essential nutrients including omega-3 fatty acids, and it is part of a healthy diet. On the other hand, the consumption of large quantities of fish in which mercury has accumulated is hazardous to the fetus and the nervous system of young children. For this reason it is recommended that pregnant or nursing women and young children avoid some types of fish (i.e., shark, swordfish, king mackerel, and tilefish) and eat certain other fish and shellfish only in limited quantities. The following fish and shellfish currently have mercury levels that are low enough to allow consumption by these subpopulation groups in limited quantities: shrimp; salmon; pollack/pollock (i.e., bluefish, walleye); catfish; and canned light tuna (not albacore tuna, white tuna, or tuna steak). The level of mercury in the local rivers and lakes determines the mercury level and safety of locally caught fish (ATSDR, 1999c). It is advisable to check on the local conditions to determine the safety of locally caught fish or avoid intake. Because mercury accumulates in the body over time, the FDA recommends that women who are planning to become pregnant or who are pregnant eat no more than 12 ounces of fish a week on average and that children consume smaller quantities (CFSAN, 2001; EPA/FDA, 2004). SUMMARY This review of the literature of nutrition-related health risks for the population served by the WIC program indicates several areas of concern for all groups: obesity; poor iron status; and contamination of food with dioxin and methyl mercury. Low folate intake is a concern for all women during their reproductive years because of the importance of the peri-conception period in prevention of neural tube defects. Insufficient calcium intake for a pregnant or breastfeeding woman may be associated with potential lead toxicity for the fetus or infant. Low intake of vitamin D appears to be a concern for all women of reproductive age. These health concerns are summarized in Table 5-1. TABLE 5-1 Summary of Health Concerns from Analysis of NutritionRelated Health Risks and Outcomes in the WIC-Eligible Population Topic Health Concern WIC Population Affected Vitamin D Low intake of vitamin D All women of reproductive age Folate Low intake of folate All women of reproductive age Calcium Low intake of calcium Pregnant or breastfeeding women Iron Iron deficiency anemia persists Women, infants, and children Zinc Low intake of zinc if complementary foods Breastfed infants greater than 6 months are inappropriate of age Obesity Health effects of obesity Women, infants, and children Dioxin Contamination of food with dioxin Women, infants, and children Methyl mercury Contamination of food with methyl Women, infants, and children mercury
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5-10 PROPOSED CRITERIA FOR SELECTING THE WIC FOOD PACKAGES The Committee is proposing that iron be considered a target nutrient even though intakes appear adequate in infants, children, and most women because the prevalence of anemia remains unacceptably high among these vulnerable groups (Bodnar, 2001; CDC, 2002). Although intake data were only available for formula-fed infants, iron remains a concern for both formula-fed and breastfed infants (AAP, 2004). Because the data with clinical measures of anemia are more recent than the intake data on iron and because breastfed infants were excluded from the analyses of intake data, the Committee gave extra weight to the physiological measures. It remains important that adequate intakes of iron be maintained in all individuals.
Representative terms from entire chapter: