To review the recently issued guidelines for weight gain during pregnancy.
These guidelines were developed to minimize the negative health consequences for both mother and fetus of inadequate or ...excessive weight gain. They call for categorizing women's prepregnancy BMI using the WHO/National Heart, Lung and Blood Institute cutoff points and provide ranges of recommended weight gain for underweight (28-40 lb), normal weight (25-35 lb), overweight (15-25 lb) and obese (11-20 lb) gravidas. Data were insufficient to construct specific guidelines for women with class II or class III obesity. Women should attempt to conceive at a normal weight for better obstetric outcomes. Improved comprehensive preconceptional care is necessary to help women reach this goal. Most American women currently gain weight below or above the new ranges, so changes are required in both women's behavior and how their care is managed. Data from a variety of interventions related to improved diet and increased physical activity show that individualized care can assist women in gaining weight within these guidelines.
The guidelines offer many opportunities for obstetrician/gynecologists, together with ancillary healthcare providers, to assume a larger role as 'women's healthcare physicians' and to conduct research that could improve the health of mothers and children.
Calcium and vitamin D are essential nutrients for the human body. Establishing the levels of these nutrients that are needed by the North American population is based on the understanding of the ...health outcomes that calcium and vitamin D affect. It is also important to establish how much of each nutrient may be "too much."
Dietary Reference Intakes for Calcium and Vitamin D provides reference intake values for these two nutrients. The report updates the DRI values defined in Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride , the 1997 study from the Institute of Medicine. This 2011 book provides background information on the biological functions of each nutrient, reviews health outcomes that are associated with the intake of calcium and vitamin D, and specifies Estimated Average Requirements and Recommended Dietary Allowances for both. It also identifies Tolerable Upper Intake Levels, which are levels above wish the risk for harm may increase. The book includes an overview of current dietary intake in the U.S. and Canada, and discusses implications of the study. A final chapter provides research recommendations.
The DRIs established in this book incorporate current scientific evidence about the roles of vitamin D and calcium in human health and will serve as a valuable guide for a range of stakeholders including dietitians and other health professionals, those who set national nutrition policy, researchers, the food industry, and private and public health organizations and partnerships.
Despite efforts over the past several decades to reduce sodium intake in the United States, adults still consume an average of 3,400 mg of sodium every day. A number of scientific bodies and ...professional health organizations, including the American Heart Association, the American Medical Association, and the American Public Health Association, support reducing dietary sodium intake. These organizations support a common goal to reduce daily sodium intake to less than 2,300 milligrams and further reduce intake to 1,500 mg among persons who are 51 years of age and older and those of any age who are African-American or have hypertension, diabetes, or chronic kidney disease.
A substantial body of evidence supports these efforts to reduce sodium intake. This evidence links excessive dietary sodium to high blood pressure, a surrogate marker for cardiovascular disease (CVD), stroke, and cardiac-related mortality. However, concerns have been raised that a low sodium intake may adversely affect certain risk factors, including blood lipids and insulin resistance, and thus potentially increase risk of heart disease and stroke. In fact, several recent reports have challenged sodium reduction in the population as a strategy to reduce this risk.
Sodium Intake in Populations recognizes the limitations of the available evidence, and explains that there is no consistent evidence to support an association between sodium intake and either a beneficial or adverse effect on most direct health outcomes other than some CVD outcomes (including stroke and CVD mortality) and all-cause mortality. Some evidence suggested that decreasing sodium intake could possibly reduce the risk of gastric cancer. However, the evidence was too limited to conclude the converse-that higher sodium intake could possibly increase the risk of gastric cancer. Interpreting these findings was particularly challenging because most studies were conducted outside the United States in populations consuming much higher levels of sodium than those consumed in this country. Sodium Intake in Populations is a summary of the findings and conclusions on evidence for associations between sodium intake and risk of CVD-related events and mortality.
The state of nutritional health in the United States in the early part of the twentieth century was very different from today. Nutrient deficiencies and dental caries were prevalent health concerns ...for many Americans. In 1940, the US National Defense Advisory Commission asked the National Academy of Sciences for help in studying problems of nutrition in the United States. The outcome was issuance of the first RDAs. The goal of the RDAs was to recommend “…allowances sufficiently liberal to be suitable for maintenance of good nutritional status.” In the subsequent decades, a very different nutritional health challenge began to emerge for an increasing proportion of the population, that of overweight and obesity and risk of diet-related chronic disease. In part, as a response to this challenge, the RDA process was revised and the Dietary Reference Intakes (DRIs) were developed. The DRIs are a set of reference values that, when adhered to, predict a low probability of nutrient inadequacy or excessive intake. Recently, new DRI guidelines were proposed to define reference points for nutrient and food component intakes that influence risk of chronic disease. Developing DRIs for chronic disease endpoints presents unique challenges, notably, chronic diseases are multifactorial in nature and not directly nutrient-specific; the body of evidence supporting nutrients and other food substances as modifiers of risk of chronic disease is generally limited; and there is a lack of consistency in findings across study types. In addition, the latency of dietary exposures and chronic disease outcomes makes it difficult to demonstrate causality. Adapting the DRI model to meet the needs of the general population in the current context suggests a need to redefine the boundaries that describe the health of the population and to re-examine how indicators of chronic disease can be integrated effectively into the DRI process.
For many Americans who live at or below the poverty threshold, access to healthy foods at a reasonable price is a challenge that often places a strain on already limited resources and may compel them ...to make food choices that are contrary to current nutritional guidance. To help alleviate this problem, the U.S. Department of Agriculture (USDA) administers a number of nutrition assistance programs designed to improve access to healthy foods for low-income individuals and households. The largest of these programs is the Supplemental Nutrition Assistance Program (SNAP), formerly called the Food Stamp Program, which today serves more than 46 million Americans with a program cost in excess of $75 billion annually. The goals of SNAP include raising the level of nutrition among low-income households and maintaining adequate levels of nutrition by increasing the food purchasing power of low-income families.
In response to questions about whether there are different ways to define the adequacy of SNAP allotments consistent with the program goals of improving food security and access to a healthy diet, USDA's Food and Nutrition Service (FNS) asked the Institute of Medicine (IOM) to conduct a study to examine the feasibility of defining the adequacy of SNAP allotments, specifically: the feasibility of establishing an objective, evidence-based, science-driven definition of the adequacy of SNAP allotments consistent with the program goals of improving food security and access to a healthy diet, as well as other relevant dimensions of adequacy; and data and analyses needed to support an evidence-based assessment of the adequacy of SNAP allotments.
Supplemental Nutrition Assistance Program: Examining the Evidence to Define Benefit Adequacy reviews the current evidence, including the peer-reviewed published literature and peer-reviewed government reports. Although not given equal weight with peer-reviewed publications, some non-peer-reviewed publications from nongovernmental organizations and stakeholder groups also were considered because they provided additional insight into the behavioral aspects of participation in nutrition assistance programs. In addition to its evidence review, the committee held a data gathering workshop that tapped a range of expertise relevant to its task.
The adoption of a panel of Nutrient Reference Values (NRVs) in place of a single recommended intake allowed for assessment of nutritional adequacy and safe upper intake levels for nutrients on a ...population level and for individuals. The Average Requirement (AR) and Tolerable Upper Intake Level (UL) comprise 2 core NRVs needed to obtain accurate, comparable estimates of population-level nutrient intakes, which are necessary to plan and evaluate nutrition support programs globally. Harmonizing the derivation of NRVs, particularly the AR and UL, is essential to ensure inclusion of all countries, whether high-, middle-, or low-income, in the process and to improve access for all users to the tools and data needed to carry it out. The NRV process today is more rigorous and transparent than the first derivation of DRIs because of adoption of systematic reviews and bias assessment methodologies, updated food and nutrient databases, data on cultural and context-specific dietary patterns, and better metabolic markers of nutritional status. A proposed framework for the derivation of NRVs builds on available methodologies to support the NRV process; however, this is not sufficient to achieve harmonization of the process. Fundamental to moving forward toward harmonization is removing existing barriers, including limited access to resources and databases and variance in terminology used to identify specific NRVs; adoption of more rigorous and transparent methodologies, including chronic disease endpoints, in the review process; and creating a central repository for easily accessible evidence. Chief among the barriers to harmonization is a willingness of global bodies to support an agreed-upon approach to the derivation process. Improving access to tools and data resources and providing guidance and support to encourage their adoption are critical to achieving harmonization of the NRV process.
Planning nutritionally adequate intakes for large groups of people presents many challenges. Because of between-person variations in both food choices and nutrient requirements, it is necessary to ...examine nutrient intake distributions and select a Target Median Intake (TMI) that will lead to a low prevalence of inadequate nutrient intakes. The TMI may then be used to guide a feeding or education program. A comprehensive report from the Institute of Medicine evaluated nutrient intakes from the NHANES and recommended new meal patterns for all age groups (other than infants) served by the Child and Adult Day Care Food Program, which provides meals and snacks to children and adults in a variety of care settings. The Estimated Average Requirement, a DRI value, for each nutrient of interest was used to estimate both the prevalence of inadequate intakes as well as the changes in the intake distribution that are needed to reduce unacceptably high levels of inadequacy. For nutrients with an Adequate Intake (AI), the prevalence of inadequacy could not be estimated, but the AI could be used as the TMI. Simultaneously, it was important to ensure that the new intake distributions did not result in intakes that exceeded the Tolerable Upper Intake Level for any nutrient. Data for 2- to 4-y-old children are presented in detail to illustrate this process. Of 18 nutrients examined, analyses showed that intakes of vitamin E, potassium, and fiber should be increased, while intakes of sodium should be decreased. If more recent nutrient standards are used, revised assessments show that calcium intake should also be increased, while potassium intake is adequate. These methods and results should be useful when designing feeding programs for other population groups within the United States, as well as in other countries.
Nutrition assistance programs, including the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), the National School Lunch and School Breakfast Programs (NSLP/SBP), and the ...Child and Adult Care Food Program (CACFP), are intended to offer low‐income families the opportunity for a healthier food pattern that promotes overall health and reduces risk for chronic disease. To be successful in improving the diets of underserved Americans requires a unified approach toward meeting the nutritional needs of program participants. Newly revised recommendations increase intakes of fruits, vegetables, and whole‐grain‐rich foods while reducing consumption of saturated fats, added sugars, and sodium. In addition to improving the nutritional profile of meals and snacks for NSLP and CACFP and meal patterns for WIC, the new recommendations ensure variety within food groups for menus across a week and allow for regional and cultural preferences and increased flexibility of choice within food groups. The newly revised meal pattern recommendations are broadly applicable to the design of feeding programs for any age group and for any combination of meals and snacks being provided.
Dietary Reference Intakes (DRIs) are fundamental to inform national nutrition policy. However, a regular systematic review of the 51 nutrients that have DRIs has limited feasibility, and many DRIs ...have not been reviewed in >15 y.
To address this issue, individuals (nutrient review group) who were members of the Food and Nutrition Board developed a streamlined, evidence-based methodology that could be used to identify nutrients potentially in need of a systematic review.
The proposed methodology, termed an evidence scan, comprises several steps. First, an analytic framework is developed to identify markers of associations between intake of a nutrient and a corresponding clinical outcome. Next, the framework is used to direct the identification of keywords for a scan of published research that is potentially relevant to intake requirements or upper intake levels for a nutrient. Last, a panel of content experts selects the abstracts that are likely to be relevant and reviews the full publications. The results may be used to determine whether a revision of the nutrient's DRI is an immediate priority but would not supplant a comprehensive systematic evidence review.
To illustrate the process, 2 nutrients were selected as case studies: thiamin and phosphorus (DRIs were last set in 1998 and 1997, respectively). Using the evidence scan for thiamin, we identified 70 potentially relevant abstracts, of which 9 full publications were reviewed. For phosphorus, 127 potentially relevant abstracts were identified, and 29 full publications were reviewed.
From the review of these 2 nutrients, the nutrient review group concluded that there was insufficient new evidence to assign a high priority to a comprehensive systematic review for either thiamin or phosphorus. Evidence scanning is an efficient method of identifying DRI nutrients that are most in need of either a new or an updated systematic review.
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