Infancy

Infancy covers the period from birth through 12 months of age and is divided into two 6-month intervals. Except for energy, the first 6-month interval was not subdivided further because intake is relatively constant during this time. That is, as infants grow, they ingest more food however, on a body-weight basis their intake remains nearly the same. During the second 6 months of life, growth velocity slows, and thus daily nutrient needs on a body-weight basis may be less than those during the...

Methodological Considerations

The quality of nutrient intake data varies widely across studies. The most valid intake data are those collected from the metabolic study protocols in which all food is provided by the researchers, amounts consumed are measured accurately, and the nutrient composition of the food is determined by reliable and valid laboratory analyses. Such protocols are usually possible with only a few subjects. Thus, in many studies, intake data are self-reported (e.g., through 24-hour recalls of food intake,...

Nonprotein Pathways of Amino Acid Nitrogen Utilization

Although in general the utilization of dietary amino acids is dominated by their incorporation into protein and their role in energy metabolism, amino acids are also involved in the synthesis of other nitrogenous compounds important to physiological viability as shown in Table 10-5. Some pathways have the potential for exerting a substantial impact on the utilization of certain amino acids, and may be of potential significance for the requirements for these amino acids. This is particularly...

Physiological Adaptations to Protein Metabolism During Pregnancy

Whole body protein turnover, measured by leucine kinetics, is increased in pregnant women at weeks 24 and 35 compared with pregnant women at 13 weeks or with nonpregnant women (Thompson and Halliday, 1992). Similar observations of increased whole body protein turnover during pregnancy have been made using 15N lysine as a tracer (Kalhan and Devapatla, 1999). A significant reduction in urea synthesis has been shown to occur in the first trimester and is sustained throughout pregnancy (Kalhan et...

Maintenance Protein Needs

Even when mammals consume no protein, nitrogen continues to be lost. Provided that the energy intake is adequate, these basal losses are closely related to body weight and basal metabolic rate (Castaneda et al., 1995b Scrimshaw et al., 1972). In man, normal growth is very slow and the dietary requirement to support growth is small in relation to maintenance needs except at very young ages. Moreover, the human being is a long- lived species. It follows that maintenance needs are of particular...

Methods To Determine The Adequate Intake For Infants

As for other nutrients in previous Dietary Reference Intake (DRI) reports, the Adequate Intake (AI) for young infants (ages 0 through 6 months) is generally estimated to be the average intake by full-term infants who are born to healthy, well-nourished mothers and who are exclusively fed human milk. The extent to which intake of a nutrient from human milk may exceed the actual requirements of infants is not known, and ethics of human experimentation preclude the testing of levels known to be...

Added Sugars

Added sugars are defined as sugars and syrups that are added to foods during processing or preparation. Major sources of added sugars include soft drinks, cakes, cookies, pies, fruitades, fruit punch, dairy desserts, and candy (USDA HHS, 2000). Specifically, added sugars include white sugar, brown sugar, raw sugar, corn syrup, corn-syrup solids, high-fructose corn syrup, malt syrup, maple syrup, pancake syrup, fructose sweetener, anhydrous dextrose, and crystal dextrose. Since added sugars...

Adults Ages 19 Years and Older Evidence Considered in Estimating the Average Requirement

Long-term data in Westernized populations, which could determine the minimal amount of carbohydrate compatible with metabolic requirements and for optimization of health, are not available. Therefore, it is provisionally suggested that an EAR for carbohydrate ingestion in the context of overall food energy sufficiency be based on an amount of digestible carbohydrate that would provide the brain (i.e., central nervous system) with an adequate supply of glucose...

Arginine

L-Arginine is incorporated into tissue proteins, and is required for the synthesis of other amino acids, polyamines, and creatine, as well as for the detoxification of ammonia via the urea cycle (Rodwell, 1990). It is a dispensable glycogenic amino acid, synthesized in adequate amounts from the urea cycle intermediate ornithine. Ornithine, in turn, can be synthesized from proline and possibly from glutamate (Brunton et al., 1999). However, in children with congenital defects of argininosuccinic...

Rda Ear 2 X SDrequirement

If data about variability in requirements are insufficient to calculate an SDrequirement for that specific nutrient in that population group, but normality or symmetry can be assumed, then a coefficient of variation (CV) of 10 percent will be assumed and the calculation becomes INTRODUCTION TO DIETARY REFERENCE INTAKES 25 RDA EAR + 2 (0.1 x EAR) 1.2 x EAR. The assumption of a 10 percent CV is based on extensive data on the variation in basal metabolic rate (FAO WHO UNA, 1985 Garby and Lammert,...

Physical Activity

Although consumption of high GI test foods increases glucose oxidation and suppresses the availability of free fatty acids (Ritz et al., 1991), for factors that would be predicted to have an adverse effect on the capacity for endurance exercise there are conflicting reports on whether consumption of high GI diets prior to exercise results in measurably adverse exercise performance. Some studies report a negative effect of consumption of high GI carbohydrates prior to exercise compared with...

Evidence Considered For Estimating The Average Requirement For Carbohydrate

The endogenous glucose production rate, and thus the utilization rate, depends on the duration of starvation. Glucose production has been determined in a number of laboratories using isotopically labeled glucose (Amiel et al., 1991 Arslanian and Kalhan, 1992 Bier et al., 1977 Denne and Kalhan, 1986 Kalhan et al., 1986 King et al., 1982 Patel and Kalhan, 1992). In overnight fasted adults (i.e., postabsorptive state), glucose production is approximately 2 to 2.5 mg kg min, or approximately 2.8 to...

Evidence Considered in Estimating the Average Requirement

Pregnancy results in an increased metabolic rate and thus an increased fuel requirement. This increased fuel requirement is due to the establishment of the placental-fetal unit and an increased energy supply for growth and development of the fetus. It is also necessary for the maternal adaptation to the pregnant state and for moving about the increased mass of the pregnant woman. This increased need for metabolic fuel often includes an increased maternal storage of fat early in pregnancy, as...

Balance Of Carbohydrate And Lipid Oxidation During Exercise And Recovery

The balance of carbohydrate and lipid used by an individual during exercise depends mainly on relative intensity, or level of effort as related to the individual's maximal rate of oxygen consumption (Vo2max) the greatest oxygen consumption that can be attained during an all out physical effort). In general, Vo2max is related to body muscle mass and is a relatively constant value for a given individual but it can be altered by various factors, particularly aerobic training, which will induce a...

Intervention Studies

Most intervention studies on fiber and breast cancer have examined fiber intake and plasma or urinary indicators of estrogen (e.g., estrone, estradiol). Since certain breast cancers are hormone dependent, the concept is that fiber may be protective by decreasing estrogen concentrations. Rose and coworkers (1991) provided three groups of premenopausal women with a minimum of 30 g d of Dietary Fiber from wheat, oats, or corn. After 2 months, wheat bran was shown to decrease plasma estrone and...

Adverse Effects

Adaptation to High Levels of Energy Intake. The ability of healthy individuals to compensate for increases in energy intake by increasing energy expenditure (either for physical activity or resting metabolism) depends on physiological and behavioral factors. When individuals are given a diet providing a fixed (but limited) amount of energy in excess of the requirements to maintain body weight, they will initially gain weight. However, over a period of several weeks, their energy expenditure...

Obesity

Obesity results from an imbalance between energy intake and energy expenditure. The health risks associated with obesity include increased mortality, hypertension, cardiovascular disease, diabetes mellitus, gallbladder disease, some cancers, and changes in endocrine function and metabolism (NHLBI NIDDK, 1998). The risk factors for becoming obese are not entirely understood but are thought to include genetics, food intake, physical inactivity, and some rare metabolic disorders (NHLBI NIDDK,...

Gums

While the adverse gastrointestinal effects of gums are limited, incidences of moderate to severe degrees of flatulence were reported from a trial in which 4 to 12 g d of a hydrolyzed guar gum were provided to 16 elderly patients (Patrick et al., 1998). Allergic Reactions. Gums such as the exudate gums, gum arabic, and gum tragacanth have been shown to elicit an immune response in mice (Strobel et al., 1982). Occupational asthma caused by guar gum has been reported...

Classification of Dietary Carbohydrates

Carbohydrates can be subdivided into several categories based on the number of sugar units present. A monosaccharide consists of one sugar unit such as glucose or fructose. A disaccharide (e.g., sucrose, lactose, and maltose) consists of two sugar units. Oligosaccharides, containing 3 to 10 sugar units, are often breakdown products of polysaccharides, which contain more than 10 sugar units. Oligosaccharides such as raffinose and stachyose are found in small amounts in legumes. Examples of...

Physical Activity for Pregnant Women

For women who have been previously physically active, continuation of physical activities during pregnancy and postpartum can be advantageous (Mottola and Wolfe, 2000). Unfortunately, too much or improper activity can be injurious to the woman and fetus. Regular exercise during pregnancy counteracts the effects of deconditioning that lead to fatigue, loss of muscle tone, poor posture, joint laxity, back pain, and muscle cramping (Brooks et al., 2000). Likewise, physical fitness improves glucose...

TABLEJ3 Median Nutrient Intakes by Range of Percent of Daily Energy Intake from Added Sugars Boys 14 Through 18 Years of

A AI Adequate Intake, EAR Estimated Average Requirement, RAE retinol activity equivalents. c Percent ranges of energy from added sugars have been assigned a letter (a-h). When ranges of intakes do not share the same letter, they are significantly different (p < 0.5). d Estimates of mg of a-tocopherol were obtained by multiplying estimates of mg of a-tocopherol equivalents by 0.8. NOTE Data are limited to individuals who provided a complete and reliable 24-hour dietary recall on Day 1....

Nitrogen Versus Amino Acids

Absorbed nitrogen is mainly in the form of amino acids, but a proportion is in other compounds such as nucleic acids, creatine, amino sugars, ammonia, and urea. The quantitative extent to which these contribute to nitrogen retention and homeostasis is not known. Creatine can probably be utilized (Metges et al., 1999b), but in general it is unknown to what extent these different compounds can have a sparing effect on the utilization of the amino acids for which they are precursors. However, the...

Nutrient Functions And The Indicators Used To Estimate Requirements

Energy is required to sustain the body's various functions, including respiration, circulation, physical work, and protein synthesis. This energy is supplied by carbohydrates, proteins, fats, and alcohol in the diet. The energy balance of an individual depends on his or her dietary energy intake and energy expenditure. The Estimated Energy Requirement (EER) is defined as the average dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender,...

Physical Activity for Children

Measurements of the energy expended in various activities are much more limited in children than adults. Torun (1990) compiled the energy expenditure of several common activities in children from 28 studies and expressed the data as multiples of basal metabolic rate (BMR). The activities APAL week 2.025 + 2.505 4.530 mean APAL day 4.53 7 0.65 mean PAL 1.1 + mean APAL day 1.75 were classified into 10 categories as shown in Tables 12-4 (Boys) and 12-5 (Girls). When the data are expressed as...

Special Considerations

Individuals adapted to a very low carbohydrate diet can perform adequately for extended periods of time at power outputs represented by exercise at less than 65 percent O2 max (Miller and Wolfe, 1999). For extended periods of power output exceeding this level, the dependence on carbohydrate as a fuel increases rapidly to near total dependence (Miller and Wolfe, 1999). Therefore, for such individuals there must be a corresponding increase in carbohydrate derived directly from...

Infants Ages 0 Through 6 Months Method Used to Set the Adequate Intake

The recommended intakes of protein are based on an Adequate Intake (AI) that reflects the observed mean protein intake of infants fed principally with human milk. Human Milk. Human milk is recognized as the optimal source of nutrients for infants throughout at least the first year of life and is recommended as the sole nutritional source for infants during the first 4 to 6 months of life (IOM, 1991). There are no reports of apparently healthy, full-term infants, exclusively fed human milk, who...

Dose Response Assessment

Studies of oral administration of supplemental arginine in humans (in excess of normal dietary intakes of approximately 5.4 g 100 g of mixed dietary proteins) were not designed to systematically study the toxicity of chronic oral exposure to this amino acid. They are generally of short dura- tion, do not present dose-response data, and involve small numbers of individuals. Although data from these studies do not support the development of an LOAEL and thus a UL, they do give some indication of...

Fat Absorption and Aging

Aging in humans has been associated with a decrease in liver size and hepatic blood flow, slightly decreased serum albumin concentrations, and normal routine liver chemistries (Russell, 1992). Pancreatic secretion after initial stimulation with either secretin or pancreozymin is not diminished with age (Bartos and Groh, 1969). Similarly, 72-hour fecal fat excretion in response to a dietary fat challenge in young (19 to 44 years of age) and old TABLE 8-1 Randomized Studies of n-3 Fatty Acids and...

Physiology of Digestion Absorption and Metabolism Digestion

The breakdown of starch begins in the mouth where salivary amylase acts on the interior a-(1,4) linkages of amylose and amylopectin. The digestion of these linkages continues in the intestine where pancreatic amylase is released. Amylase digestion produces large oligosaccharides (a-limit dextrins) that contain approximately eight glucose units of one or more a-(1,6) linkages. The a-(1,6) linkages are cleaved more easily than the a-(1,4) linkages. Oligosaccharides and Sugars. The...

Insulin Sensitivity and Type 2 Diabetes

Insulin has three major effects on glucose metabolism it decreases hepatic glucose output, it increases glucose utilization in muscle and adipose tissue, and it enhances glycogen production in the liver and muscle. Insulin sensitivity measures the ability to do these effectively. Individuals vary genetically in their insulin sensitivity, some being much more efficient than others (Reaven, 1999). Obesity is related to decreased insulin sensitivity (Kahn et al., 2001), which can also be...

Rationale for Definitions

Nondigestible carbohydrates are frequently isolated to concentrate a desirable attribute of the mixture from which it was extracted. Distinguishing a category of Functional Fiber allows for the desirable characteristics of such components to be highlighted. In the relatively near future, plant and animal synthetic enzymes may be produced as recombinant proteins, which in turn may be used in the manufacture of fiber-like materials. The definition will allow for the inclusion of these materials...

Low Fat High Carbohydrate Diets of Adults

The chronic diseases of greatest concern with respect to relative intakes of macronutrients are CHD, diabetes, and cancer. In this section, the relationship between total fat and total carbohydrate intakes are considered. Comparisons are made in terms of percentage of total energy intake. For example, a low fat diet signifies a lower percentage of fat relative to total energy. It does not imply that total energy intake is reduced because of consumption of a low amount of fat. The distinction...

Resistance Exercise and General Physical Fitness

Initial efforts by health professionals to reduce FM involved endurance exercise protocols mainly because of the large impact on total energy expenditure and links to coronary heart disease risk amelioration. More recent efforts using resistance exercise training, or combinations of resistance and endurance exercises, have been tried to maintain the interest of participants as well as to positively affect body composition through stimulation of anabolic stimuli (Grund et al., 2001)....

Young Adulthood and Middle Aged Adults Ages 19 Through 30 Years and 31 Through 50 Years

The recognition of the possible value of higher nutrient intakes during early adulthood on achieving optimal genetic potential for peak bone mass was the reason for dividing adulthood into ages 19 through 30 years and 31 through 50 years. Moreover, mean energy expenditure decreases during this 30-year period, and needs for nutrients related to energy metabolism may also decrease. For some nutrients, the DRIs may be the same for the two age groups. However, for other nutrients, especially those...

Saturated Fatty Acids

When saturated fatty acids are ingested along with fats containing appreciable amounts of unsaturated fatty acids, they are absorbed almost completely by the small intestine. In general, the longer the chain length of the fatty acid, the lower will be the efficiency of absorption. However, unsaturated fatty acids are well absorbed regardless of chain length. Studies with human infants have shown the absorption to be 75, 62, 92, and 94 percent of palmitic acid, stearic acid, oleic...

Type 2 Diabetes Mellitus

Type 2 diabetes mellitus is characterized by a genetic predisposition to the disorder, decreased tissue sensitivity to insulin (insulin resistance), and impaired function of pancreatic P-cells, which control the timely release of insulin (Anderson, 1999). Obesity, physical inactivity, and advancing age are primary risk factors for insulin resistance and development of type 2 diabetes (Barrett-Connor, 1989 Colditz et al., 1990 Helmrich et al., 1991 Manson et al., 1991). Dietary factors have also...

Criteria And Proposed Values For Tolerable Upper Intake Levels

A risk assessment model is used to derive Tolerable Upper Intake Levels (ULs). The model consists of a systematic series of scientific considerations and judgments. The hallmark of the risk assessment model is the requirement to be explicit in all of the evaluations and judgments made. There were insufficient data to use the model of risk assessment to set a UL for total fat, monounsaturated fatty acids, n-6 and n-3 polyunsaturated fatty acids, protein, or amino acids. While increased serum low...

How the Definitions Affect the Interpretation of This Report

The reason that a definition of fiber is so important is that what is or is not considered to be dietary fiber in, for example, a major epidemiological study on fiber and heart disease or fiber and colon cancer, could determine the results and interpretation of that study. In turn, that would affect recommendations regarding fiber intake. Clearly, the definitions described above were developed after the studies cited in this report, which form the basis for fiber intake recommendations....

Trans Fatty Acids

Trans fatty acids are unsaturated fatty acids that contain at least one double bond in the trans configuration. The trans double-bond configuration results in a larger bond angle than the cis configuration, which in turn results in a more extended fatty acid carbon chain more similar to that of saturated fatty acids rather than that of cis unsaturated, double-bond-containing fatty acids. The conformation of the double bond impacts on the physical properties of the fatty acid. Those fatty acids...

Dietary Fiber and Protection Against Breast Cancer

A growing number of studies have reported on the relationship of Dietary Fiber intake and breast cancer incidence, and the strongest case can be made for cereal consumption rather than consumption of Dietary Fiber per se (for an excellent review see Gerber 1998 ). Between-country studies, such as England versus Wales (Ingram, 1981), southern Italy versus northern Italy versus the United States (Taioli et al., 1991), and China versus the United States (Yu et al., 1991), and one study within...

Dietary Carbohydrate

A negative correlation between total sugars intake and body mass index has been reported in adults (Dreon et al., 1988 Dunnigan et al., 1970 Fehily et al., 1984 Gibson, 1993, 1996b Miller et al., 1990). Increased added sugars intakes have been shown to result in increased energy intakes of children and adults (see Chapter 6) (Bowman, 1999 Gibson, 1996a, 1997 Lewis et al., 1992). In spite of this, a negative correlation between added sugars intake and body mass index has been observed in...

Physiological Effects of Isolated and Synthetic Fibers

This section summarizes the fibers for which there is a sufficient database that documents their beneficial physiological human effects, which is the rationale for categorizing them as Functional Fibers. It is important to note that discussions on the potential benefits of what might eventually be classified as Functional Fibers should not be construed as endorsements of those fibers. While plant-based foods are a good source of Dietary Fiber, isolated or synthetic fibers have been developed...

Using the Estimated Average Requirement and the Recommended Dietary Allowance

The Estimated Average Requirement (EAR) estimates the median of a distribution of requirements for a specific life stage and gender group, but it is not possible to know where an individual's requirement falls within this distribution without further anthropometric, physiological, or biochemical measures. Thus from dietary data alone, it is only possible to estimate the likelihood of nutrient adequacy or inadequacy. Furthermore, only rarely are precise and representative data on the usual...

Saturated Fatty Acids Trans Fatty Acids and Cholesterol

No RDAs, AIs, or AMDRs are provided for saturated fatty acids, trans fatty acids, and cholesterol. However, with increasing intakes of either of these three nutrients, there is an increased risk of coronary heart disease. Chapter 11 provides some dietary guidance on ways to reduce the intake of saturated fatty acids, trans fatty acids, and cholesterol. For example, when planning diets, it is desirable to replace saturated fat with either monounsaturated or polyunsaturated fats to the greatest...

Hazard Identification

Histidine given acutely by intraperitoneal injection or intravenously has been shown to result in changes in the concentration of brain amino acids (Oishi et al., 1989) and histamine (Schwartz et al., 1972). Young rats (4 to 5 weeks old) treated with an inhibitor of histidinase exhibited reduced locomotor activity after an intra-peritoneal injection of histidine (250 mg kg of body weight) (Dutra-Filho et al., 1989). Pilc and coworkers (1982) reported bizarre behavior...

Growth and Neural Development

The membrane lipids of brain gray matter and the retina contain very high concentrations of DHA, particularly in the amino phospholipids phosphatidylethanolamine and phosphatidylserine. In these tissues, the concentration of DHA can exceed 50 percent of the fatty acids resulting in the presence of di-DHA phospholipid species. During n-3 fatty acid deficiency, DHA is tenaciously retained, thus most animal studies investigating the importance of n-3 fatty acids have used rats deprived of n-3...

Impact of Trans Fatty Acids on n6 and n3 Metabolism

The trans isomers of oleic acid and linoleic acid, which are present in hydrogenated vegetable oils and meats, have been suggested to have adverse effects on growth and development through inhibition of the desaturation of linoleic acid and a-linolenic acid to arachidonic acid and DHA, respectively (Sugano and Ikeda, 1996). Desaturation and elongation of trans linoleic and a-linolenic acid isomers containing a double bond at the cis-12 and cis-15 position, respectively, with formation of 20 and...

Determination Of Adequacy Adequacy

In the derivation of Estimated Average Requirements (EARs) or Adequate Intakes (AIs), close attention has been paid to the determination of the most appropriate indicators of adequacy. A key question is, Adequate for what In many cases, a continuum of benefits may be ascribed to various levels of intake of the same nutrient. One criterion may be deemed the most appropriate to determine the risk that an individual will become deficient in the nutrient, whereas another may relate to reducing the...

N3 Polyunsaturated Fatty Acids

Tissue levels of arachidonic acid, as well as the amounts of arachidonic acid and EPA- derived eicosanoids that are formed, have important effects on many physiological processes (e.g., platelet aggregation, vessel wall constriction, and immune cell function) via the biosynthesis of eicosanoids. Thus, the amount of n-3 fatty acids and their effects on arachidonic acid metabolism are relevant to many chronic diseases. EPA also appears to have specific effects on fatty acid metabolism, resulting...

Thresholds

A principal feature of the risk assessment process for noncarcinogens is the long-standing acceptance that no risk of adverse effects is expected unless a threshold dose (or intake) is exceeded. The adverse effects that may be caused by a nutrient almost certainly occur only when the threshold dose is exceeded (NRC, 1994 WHO, 1996). The critical issue concerns the methods used to identify the approximate threshold of toxicity for a large and diverse human population. Because most nutrients are...

Using the Recommended Dietary Allowance

Individuals should use the Recommended Dietary Allowance (RDA) as the target for their intakes for those nutrients for which RDAs have been established. Intakes at this level ensure that the risk to individuals of not meeting their requirements is very low (2 to 3 percent). For example, the RDA for protein for adults is 0.8 g kg day, or 56 and 46 g day for reference men and women weighing 70 kg and 57 kg, respectively. For a small adult weighing 45 kg, the recommended protein intake would be 36...

Coronary Artery Disease

It is well documented that high dietary protein in rabbits induces hypercholesterolemia and arteriosclerosis (Czarnecki and Kritchevsky, 1993). However, this effect has not been consistently shown in either swine (Luhman and Beitz, 1993 Pfeuffer et al., 1988) or humans. In humans, analysis of data from the Nurses' Health Study showed an inverse relationship between protein intake and risk of cardiovascular disease (Hu et al., 1999). The association was weak but suggests that high protein intake...

Physical Activity for Adults

The rationale for categorizing the cross-sectional data on adults in the doubly labeled water (DLW) database by PAL (Appendix Table I-3), as sedentary (PAL > 1.0 < 1.4), low active (PAL > 1.4 < 1.6), active (PAL > 1.6 < 1.9), and very active (PAL > 1.9 < 2.5) categories is provided in Chapter 5. Ideally, PAL of an individual can be determined from DLW studies however, in nonexperimental situations, heart rate monitors, accelerometers, and other devices as well as activity...

Identification of a NOAEL or LOAEL

A nutrient can produce more than one toxic effect (or endpoint), even within the same species or in studies using the same or different exposure durations. The NOAELs and LOAELs for these effects will ordinarily differ. The critical endpoint used to establish a UL is the adverse biological effect exhibiting the lowest NOAEL (e.g., the most sensitive indicator of a nutrient's toxicity). Because the selection of uncertainty factors (UFs) depends in part upon the seriousness of the adverse effect,...

Digestibility

Nitrogen is excreted in the feces in amounts that usually vary between 10 and 25 percent of the nitrogen intake. As mentioned earlier, only a part of this is derived directly from dietary nitrogen that was not absorbed the other parts result from protein and other secretions into the gastrointestinal tract during the process of digestion and from nitrogen con- tained in fecal bacteria. The unabsorbed part represents mainly proteins that, by reason of their physical characteristics or chemical...

New Reference Heights and Weights

As is described in Appendix B, the DRI framework is an iterative process that was undertaken in 1994. At that time, reference heights and weights used in the DRI reports for the U.S. and Canadian populations were developed based on data from the Third National Health and Nutrition Examination Survey on body mass index (BMI) for children and young adults (IOM, 1997). With the recent publication of new U.S.-based growth charts for infants and children and the introduction of BMI recommendations...

Extrinsic and Intrinsic Sugars

The terms extrinsic and intrinsic sugars originate from the United Kingdom Department of Health. Intrinsic sugars are defined as sugars that are present within the cell walls of plants (i.e., naturally occurring), while extrinsic sugars are those that are typically added to foods. An additional phrase, non-milk extrinsic sugars, was developed due to the lactose in milk also being an extrinsic sugar (FAO WHO, 1998). The terms were developed to help consumers differentiate sugars inherent to...

Limitations of the Method

The nitrogen balance method does have substantial practical limitations and problems. First, the rate of urea turnover in adults is slow, so several days of adaptation are required for each level of dietary protein tested to attain a new steady state of nitrogen excretion (Meakins and Jackson, 1996 Rand et al., 1976). Second, the execution of accurate nitrogen balance measurements requires very careful attention to all the details of the procedures involved. Since it is easy to overestimate...

Resistant Starch

Increased fecal bulk due to increased starch intake has been reported (Shetty and Kurpad, 1986). The impact of resistant starch (RS3) from a corn-based cereal on colonic function was measured in eight male volunteers (Tomlin and Read, 1990). After consuming 10.33 g d of RS3 for 1 week, there was no significant difference in fecal output, stool frequency, ease of defecation, whole-gut transit time, or degree of flatulence compared to an intake of 0.86 g d of RS3 from a rice-based...

The EAR Cut Point Method

In most situations a cut-point method using the Estimated Average Requirement (EAR) may be used to estimate the prevalence of inadequate intakes. This cut-point method is a simplification of the full probability approach of calculating the prevalence of inadequacy described by the National Research Council (NRC, 1986). The cut-point method allows the prevalence of inadequate intakes in a population to be approximated by determining the percentage of individuals in the group whose usual intakes...

Tolerable Upper Intake Levels For Protein

Humans consume a wide range of intakes of protein. As intake is increased, the concentrations of free amino acids and urea in the blood increase postprandially. The nitrogenous substances in the urine also increase, especially urea. These changes are part of the normal regulation of the amino acids and nitrogen and represent no hazards per se, at least within the range of intakes normally consumed by apparently healthy individuals. Nonetheless, a number of adverse effects have been reported,...

Using Dietary Reference Intakes To Assess Nutrient Intakes Of Groups

Suggested uses of Dietary Reference Intakes (DRIs) appear in Box S-2. The transition from using previously published Recommended Dietary Allowances (RDAs) and Reference Nutrient Intakes (RNIs) to using each of the DRIs appropriately will require time and effort by health professionals and others. For statistical reasons that are addressed briefly in Chapter 13 and in more detail in the report Dietary Reference Intakes Applications in Dietary Assessment (IOM, 2000), the Estimated Average...

What Are Dietary Reference Intakes

The reference values, collectively called the Dietary Reference Intakes (DRIs), include the Estimated Average Requirement (EAR), Recommended Dietary Allowance (RDA), Adequate Intake (AI), and Tolerable Upper Intake Level (UL) (Box 1-1). Establishment of these reference values requires that a criterion of nutritional adequacy be carefully chosen for each nutrient, and that the population for whom these values apply be carefully defined. A requirement is defined as the lowest continuing intake...

Dietary Intakes In The United States And Canada Sources of Dietary Intake Data

The major sources of current dietary intake data for the U.S. population include the Third National Health and Nutrition Examination Survey (NHANES III), which was conducted from 1988 to 1994 by the U.S. Department of Health and Human Services, and the Continuing Survey of Food Intakes by Individuals (CSFII), which was conducted by the U.S. Department of Agriculture (USDA) from 1994 to 1996. NHANES III examined 30,000 individuals aged 2 months and older. A single 24-hour diet recall was...

Method Used to Estimate Weight Maintenance in Normalweight Overweight and Obese Adults

TEE predictive equations were also developed combining normal-weight, overweight, and obese adults (BMI 18.5 kg m2 and higher) as mentioned earlier the coefficients and standard errors are shown in Appendix Table I-11. Mean of the residuals did not differ from zero. For the combined data sets, the standard deviations of the residuals ranged from 182 to 321. The adult predictive equations for TEE were subjected to statistical testing of their estimated coefficients and asymptotic standard...

Normalweight Overweight and Obese Women Ages 19 Years and Older TEE 387 731 x age [y PA x 109 x weight [kg 6607 x

Where PA is the physical activity coefficient PA 1.00 if PAL is estimated to be > 1.0 < 1.4 (sedentary) PA 1.14 if PAL is estimated to be > 1.4 < 1.6 (low active) PA 1.27 if PAL is estimated to be > 1.6 < 1.9 (active) PA 1.45 if PAL is estimated to be > 1.9 < 2.5 (very active) Current consensus guidelines for the management of obesity in adults (BMI 30 kg m2 and higher) recommend weight loss of around 10 percent of initial weight over a 6-month period (NIH, 2000). For overweight...

Estimation of Energy Expenditure for Weight Maintenance in Overweight Children Ages 3 Through 18 Years

While the Centers for Disease Control and Prevention (CDC) currently defines childhood risk of overweight as greater than the 85th percentile for BMI and overweight as greater than the 95th percentile of BMI, it gives no definition for obesity in childhood. Several organizations, however, define childhood obesity as a BMI above the 95th age-adjusted percentile (Barlow and Dietz, 1998 Bellizzi and Dietz, 1999). An international standardized approach was also recently proposed, based on...

Weight Reduction in Overweight Children Ages 3 Through 18 Years

Weight reduction at a rate of 1 lb m (15 g d) is equivalent to a body energy loss of 108 kcal d (assuming the energy content of weight loss averages 7.2 kcal g Saltzman and Roberts, 1995 ), an amount that is small enough to be achievable by either an increase in EEPA, a reduction in energy intake, or a combination of both. There is currently no information on changes in TEE with negative energy balance in children, and no information even from adults on changes in TEE at low levels of negative...

Examples of Dietary and Functional Fibers

As described in the report, Dietary Reference Intakes Proposed Definition of Dietary Fiber (IOM, 2001), Dietary Fiber includes plant nonstarch polysaccharides (e.g., cellulose, pectin, gums, hemicellulose, P-glucans, and fibers contained in oat and wheat bran), plant carbohydrates that are not recovered by alcohol precipitation (e.g., inulin, oligosaccharides, and fructans), lignin, and some resistant starch. Potential Functional Fibers for food labeling include isolated, nondigestible plant...

Description of the Common Dietary and Functional Fibers

Below is a description of the Dietary Fibers that are most abundant in foods and the Functional Fibers that are commonly added to foods or provided as supplements. To be classified as a Functional Fiber for food labeling purposes, a certain level of information on the beneficial physiological effects in humans will be needed. For some of the known beneficial effects of Dietary and potential Functional Fibers, see Physiological Effects of Isolated and Synthetic Fibers and Evidence Considered for...

Evidence Considered For Estimating The Requirement For Dietary Fiber And Functional Fiber

There is no biochemical assay that reflects Dietary Fiber or Functional Fiber nutritional status. Clearly one cannot measure blood fiber concentration since, by definition, fiber is not absorbed. Instead, the potential health benefits of fiber consumption, which may be compromised by a lack of fiber in the diet, have been reviewed. Throughout each section and the discussion of each indicator, a delineation is made between Dietary Fiber and Functional Fiber. It should be kept in mind that...

Mechanisms by Which Dietary Fibers May Protect Against CHD

While not explicit, several hypotheses exist to explain the mechanisms by which Dietary Fiber may protect against CHD. The lowering of serum cholesterol concentration by viscous Dietary or Functional Fibers is thought to involve changes in cholesterol or bile acid absorption, hepatic production of lipoproteins, or peripheral clearance of lipoproteins (Chen and Anderson, 1986). Viscous fibers may interfere with the absorption and enterohepatic recirculation of bile acids and cholesterol in the...

Dietary Fiber Functional Fiber and Colon Health

Constipation, Laxation, and the Contribution of Fiber to Fecal Weight. Consumption of certain Dietary and Functional Fibers is known to improve laxation and ameliorate constipation (Burkitt et al., 1972 Cummings et al., 1978 Kelsay et al., 1978 Lupton et al., 1993). In most reports there is a strong positive correlation between intake of Dietary Fiber and daily fecal weight (Birkett et al., 1997). Also, Dietary Fiber intake is usually negatively correlated with transit time (Birkett et al.,...

Dietary Fiber Intake and Colonic Adenomas

People with colonic adenomas are at elevated risk of developing colon cancer (Lev, 1990). Several epidemiological studies have reported that high Dietary Fiber and low fat intakes are associated with a lower incidence of colonic adenomas (Giovannucci et al., 1992 Hoff et al., 1986 Little et al., 1993 Macquart-Moulin et al., 1987 Neugut et al., 1993). For example, Giovannucci and coworkers (1992) studied a population of 7,284 men from the Health Professionals Follow-up Study and found a...

Possible Reasons for the Lack of a Protective Effect of Dietary Fiber in Some Trials

There is considerable debate and speculation as to why clinical intervention trials on the relationship between fiber intake and colon cancer have not shown the expected beneficial effect of fiber. Some of the possible reasons for these results are discussed below. Timing of the Intervention. Some of the recent prospective studies, such as the Nurses' Health Study (Fuchs et al., 1999) and the Health Professionals Follow-Up Study (Giovannucci et al., 1994), have failed to show a protective...

Dietary Fiber and Other Cancers

Although the preponderance of the literature on fiber intake and cancer involves colon cancer and breast cancer, several studies have shown decreased risk for other types of cancer. Because Dietary Fiber has been shown to decrease serum estrogen concentrations, some researchers have hypothesized a protective effect against hormone-related cancers such as endometrial, ovarian, and prostate. Studies on Dietary Fiber intake and endo-metrial cancer have shown both significant and nonsignificant...

Intake Of Dietary Fiber Food Sources

Marlett (1992) reported on the Dietary Fiber content of 117 frequently consumed foods. Dietary Fiber was present in the majority of fruits, vegetables, refined grains, and miscellaneous foods such as ketchup, olives, and soups, at concentrations of 1 to 3 percent, or 1 to 3 g 100 g of fresh weight. Nuts, legumes, and high fiber grains typically contained more than 3 percent Dietary Fiber. About one-third of the fiber in legumes, nuts, fruits, and vegetables was present as hemicelluloses....

Adverse Effects of Dietary Fiber Mineral Bioavailability

Within the last 20 years, several animal and human studies have shown that foods or diets rich in fibers may alter mineral metabolism, especially when phytate is present (Sandstead, 1992). Fibers may reduce the bioavailability of minerals such as iron, calcium, and zinc (AAP, 1981 Williams and Bollella, 1995). However, levels of 10 to 12 g of Dietary Fiber 1,000 kcal have been suggested as safe even for Japanese adolescents, who tradition- TABLE 7-3 Fiber Intake from an Omnivorous Diet Adequate...

Metabolism

Absorbed sugars are transported throughout the body to cells as a source of energy. The concentration of glucose in the blood is highly regulated by the release of insulin. Uptake of glucose by the adipocyte and muscle cell is dependent upon the binding of insulin to a membrane-bound insulin receptor that increases the translocation of intracellular glucose transporters (GLUT 4) to the cell membrane surface for uptake of glucose. GLUT 1 is the transporter of the red blood cell...

RRenal Failure

Restriction of dietary protein intake is known to lessen the symptoms of chronic renal insufficiency (Walser, 1992). This raises two related, but distinct questions Do high protein diets have some role in the development of chronic renal failure Do high protein intakes accelerate the progression of chronic renal failure The concept that protein restriction might delay the deterioration of the kidney with age was based on studies in rats in which low energy or low protein diets attenuated the...

Amino Acid Scoring and Protein Quality

In recent years, the amino acid requirement values for humans have been used to develop reference amino acid patterns for purposes of evaluating the quality of food proteins or their capacity to efficiently meet both the nitrogen and indispensable amino acid requirements of the individual. Based on the estimated average requirements for the individual indispensable amino acids presented earlier (Tables 10-20 and 10-21) and for total protein (nitrogen X 6.25) (Tables 10-9 and 10-13), it is...

Acceptable Macronutrient Distribution Ranges For Healthy Diets

Dietary Reference Intakes have been set for carbohydrate, n-6 and n-3 polyunsaturated fatty acids, protein, and amino acids based on controlled studies in which the actual amount of nutrient provided or utilized is known, or based on median intakes from national survey data. A growing body of evidence has shown that macronutrients, particularly fats and carbohydrate, play a role in the risk of chronic diseases. Although various guidelines have been established that suggest a maximal intake...

Clinical Effects of Inadequate Intake

The lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed. However, the amount of dietary carbohydrate that provides for optimal health in humans is unknown. There are traditional populations that ingested a high fat, high protein diet containing only a minimal amount of carbohydrate for extended periods of time (Masai), and in some cases for a lifetime after infancy (Alaska and Greenland Natives, Inuits, and...

Oat Products and fiGlucans

Extracted P-glucans are highly fermentable and therefore their contribution to fecal bulk is minimal (McBurney, 1991). This may contribute, in part, to the lack of an effect in preventing constipation. Oat bran increases stool weight by supplying rapidly fermented viscous fiber to the proximal colon for bacterial growth (Chen et al., 1998). Normalization of Blood Lipid Concentrations. In one study, oat gum supplementation (9 g d of P-glucan) did not significantly decrease serum total...

Summary of the Intervention Trials

Viscous Functional Fibers and foods sources of viscous Dietary Fiber reduce both total and LDL cholesterol concentrations, and may also reduce serum triglycerides. The amount of cholesterol reduction appears to be related to the amount of fiber consumed, although only a few studies report dose-response data. A meta-analysis of 20 trials that used high doses of oat bran, which is rich in viscous Dietary Fiber, showed that the reductions in serum cholesterol concentrations ranged from 0.1 to 2.5...

Findings By Life Stage And Gender Group

Given the capability of all tissues to synthesize sufficient cholesterol for their metabolic and structural needs, there is no evidence for a biological requirement for dietary cholesterol. As an example, many Tarahumara Indians of Mexico consume very low amounts of dietary cholesterol and have no reported developmental or health problems that could be attributed to this aspect of their diet (McMurry et al., 1982). Therefore, neither an Adequate Intake (AI) nor an Estimated Average Requirement...

Plasma Total HDL and LDL Cholesterol Concentrations

Numerous studies in humans have examined the effects of dietary cholesterol on plasma total and lipoprotein cholesterol concentrations (Tables 9-2 and 9-3, Figures 9-1 and 9-2), and empirical formulas have been derived to describe these relationships. Although most studies have TABLE 9-2 Effects of Adding Dietary Cholesterol to Defined Diets with Strict Control of Dietary Intake on Serum Cholesterol Concentration National Diet-Heart Study Research Group,1968 Bronsgeest-Schoute et al., 1979a,...

Cardiovascular Disease and CHD

An association of dietary cholesterol with cardiovascular disease is based on several lines of evidence, including studies in animal models, epidemiological data in humans, and the effects of dietary cholesterol on plasma lipoproteins (Table 9-4). There is compelling evidence that dietary cholesterol can induce atherosclerosis in several animal species, including rabbits, pigs, nonhuman primates, and transgenic mice (Bocan, 1998 McNamara, 2000 Rudel, 1997). However, given the existence of...

Approach For Setting Dietary Reference Intakes

The scientific data used to develop Dietary Reference Intakes (DRIs) have come from observational and experimental studies. Studies published in peer-reviewed journals were the principal source of data. Life stage and gender were considered to the extent possible, but the data did not provide a basis for proposing different requirements for men, for pregnant and nonlactating women, and for nonpregnant and nonlactating women in different age groups for many of the macronutrients. Three of the...

Weight Reduction in Overweight and Obese Adults

When obese individuals need to lose weight, the necessary negative energy balance can theoretically be achieved by either a reduction in energy intake or an increase in energy expenditure of physical activity (EEPA). Most usually, a combination of both is desirable (NIH, 2000) because it is hard to achieve the high levels of negative energy balance necessary for 1 to 2 lb wk weight loss with exercise alone. In support of this contention, meta-analyses show very low levels of weight loss in...

Recommended Dietary Allowance

The Recommended Dietary Allowance (RDA) is an estimate of the minimum daily average dietary intake level that meets the nutrient requirements of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group (see Figure 1-1). The RDA is intended to be used as a goal for daily intake by individuals as this value estimates an intake level that has a high probability of meeting the requirement of a randomly chosen individual (about 97.5 percent). The process for...

Chitin and Chitosan

There is no evidence that chitin or chitosan function as laxatives in humans. Normalization of Blood Lipid Concentrations. There are a number of animal studies that have suggested that chitin and chitosan may decrease lipid absorption and thus the amount of fat entering the blood (Gallaher et al., 2000 Razdan and Pettersson, 1994 Sugano et al., 1980 Zacour et al., 1992). Therefore, blood cholesterol and triacylglycerol concentrations have been shown to be reduced with chitosan intake...

Using the Acceptable Macronutrient Distribution Range

Although primarily directed at individuals, the Acceptable Macronutrient Distribution Range (AMDR) also permits assessment of populations. By determining the proportion of the group that falls below, within, and above the AMDR, it is possible to assess population adherence to recommendations and to determine the proportion of the population that is outside the range. If significant proportions of the population fall outside the range, concern could be heightened for possible adverse...

Nutritional and Metabolic Classification of Amino Acids

Older views of the nutritional classification of amino acids categorized them into two groups indispensable (essential) and dispensable (nonessential). The nine indispensable amino acids (Table 10-1) are those that have carbon skeletons that cannot be synthesized to meet body needs from simpler molecules in animals, and therefore must be provided in the diet. Although the classification of the indispensable amino acids and their assignment into a single category has been maintained in this...

Direct Amino Acid Oxidation DAAO Method

In the 1980s, Young and his coworkers introduced the use of measurements of the carbon oxidation of single indispensable amino acids as indicators of adequacy of the amino acids (Young et al., 1989). This marked a major theoretical advance over the nitrogen balance and plasma amino acid response methods. The theoretical basis of the direct amino acid oxidation (DAAO) method is that the nutritional indispensability of an amino acid is a function of its inability to synthesize its carbon...

Evidence Considered in Determining the Estimated Energy Requirement

Energy Expenditure and Energy Deposition. The energy requirements of infants and young children should balance energy expenditure at a level of physical activity consistent with normal development and allow for deposition of tissues at a rate consistent with health. This approach requires knowledge of what constitutes developmentally appropriate levels of physical activity, normal growth, and body composition. Although the energy requirement for growth relative to maintenance is small, except...

Planning for Energy for Groups

As is true for individuals, the underlying objective in planning the energy intake of a group is similar to planning intakes for other nutrients to attain an acceptably low prevalence of inadequacy and of potential excess. The approach to planning for energy, however, differs substantially from planning for other nutrients. When the Estimated Average Requirement (EAR) cut-point method is used to plan for a group's intake of nutrients such as vitamins and minerals, a low prevalence of inadequacy...

Athletes

With minor exceptions, dietary recommendations for athletes are not distinguished from the general population. As described in Chapter 12, the amount of dietary energy from the recommended nutrient mix should be adjusted to achieve or maintain optimal body weight for competitive athletes and others engaged in similarly demanding physical activities. As TABLE 5-32 Energy Needs for Catch-up Growth at Different Rates of Weight Gain TABLE 5-32 Energy Needs for Catch-up Growth at Different Rates of...

Physical Activity Level PAL

While METs describe activity intensities relative to a resting metabolic rate (RMR), the physical activity level (PAL) is defined as the ratio of total energy expenditure (TEE) to basal energy expenditure (BEE). Thus, the actual impact on PAL depends to some extent on body size and age, as these are determinants of the BEE (Figure 12-1). The impact of these factors can be judged by examining the ratio of MET (extrapolated to 24 hours) to BEE. It is noteworthy that the errors that this...

Inulin Oligofructose and Fructooligosaccharides

A few studies have demonstrated an increase in fecal bulk and increased stool frequency upon the ingestion of inulin or oligofructose. Fecal weight was increased after consuming 15 g d of inulin or oligofructose (Gibson et al., 1995), and inulin (20 to 40 g d) was shown to reduce constipation (Kleessen et al., 1997). A multicenter trial was conducted to test whether fructooligosaccharides worsen gastrointestinal symptoms in people with irritable bowel syndrome (Olesen and Gudmand-...