Chelation

Chelation is the process whereby an organic moiety acts as a ligand to bind a metal ion through two or more coordination bonds. Some low-molecular-weight compounds that may be released during the digestion of food can act as metal chelators and increase metal solubility in the intestinal lumen. In some circumstances, chelated forms of metals are naturally present in food, such as heme iron (part of hemoglobin or myoglobin protein) found in meat. Heme is a stable protoporphyrin ring-containing...

Directional Shifts

The majority of enzymes catalyze reversible reactions, and their action is highly dependent on the concentration of the reactants involved. An increase in the concentration of one reactant will drive the reaction in the direction that results in the breakdown of that reactant so as to achieve homeostasis. An example of a directional shift is the interconversion of glucose 1-phosphate and glucose 6-phosphate. During glucogenolysis, the concentration of glucose 1-phosphate increases and the...

Further Reading

Dean RFA and Whitehead RG (1963) The metabolism of aromatic amino acids in kwashiorkor. Lancet 1 188-191. Jackson AA and Grimble RF (1990) Malnutrition and amino acid metabolism. In Suskind RM and Suskind LL (eds.) The Malnourished Child, pp. 73-94. New York Raven Press. Reeds PJ and Beckett PR (1996) Protein and amino acids. In Ziegler EE and Fibr LJ Jr (eds.) Present Knowledge in Nutrition, 9th edn, pp. 67-86. Washington, DC ILSI Press. Reeds PJ, Fjeld CR, and Jahoor F (1994) Do the...

Energy Production

The body derives energy from the metabolism of carbohydrate, fat, and protein provided exogenously in the fed state and endogenously in the postabsorp-tive state. A mixture of metabolic fuels, including glucose, triacylglycerols, ketone bodies, nonesteri-fied fatty acids, alcohol, and amino acids, are present in the circulation. The proportion of these energy substrates in the blood at any one time depends on the fed or fasting state of the individual, the extent of fuel stores, and recent or...

Anthropometric Measurements Height

Height, or stature, is measured in adults and children over the age of 2 years using a stadiometer, a portable anthropometer, or a moveable headboard on a vertical measuring rod. The measuring device should be checked for accuracy using a standard 2-m steel tape. Subjects should be measured to the nearest 0.1cm. Subjects, in minimal clothing with bare heads and feet, should stand straight, arms hanging loosely to the side, feet together and with heels, buttocks and shoulder blades in contact...

Human Zinc Deficiency

In addition to dietary inadequacy, there are several routes that lead to zinc deficiency. Acrodermatitis enteropathica, the genetic disorder of zinc malabsorption, has already been mentioned. Other, more generalized, malabsorption syndromes (e.g., coeliac disease) can also lead to zinc deficiency. Deficiency has also resulted from inappropriate intravenous feeding and the use of chelation therapy. Children are likely to be particularly at risk of zinc deficiency, because of its involvement in...

Phenylalanine and Tyrosine

Phenylalanine is hydroxylated to tyrosine by the enzyme phenylalanine hydroxylase. The inborn disease phenylketonuria is characterized by a deficiency of this enzyme. Tyrosine is the precursor for dihydroxyphenylala-nine (dopa), which can successively be converted to the catecholamines dopamine, noradrenaline (nore-pinephrine) and adrenaline (epinephrine). Although only a small proportion of tyrosine is used in this pathway, this metabolic route is extremely relevant. Dopamine is an important...

Causes of Protein and Amino Acid Deficiency

Although the main cause of protein deficiency is a protein-deficient diet, the disorder can commonly occur in a variety of pathologic states. In particular, the disorder can be seen in the general context of starvation (although the deficits may be both protein and energy) or in disorders where there are specific protein losses from the body as in nephrotic syndrome or after burns. Secondary protein deficiencies can be ascribed to six causes 1. Irregular food habits and starvation states this...

Function of endothelial cells

Owing to the strategic location of the endothelium, it is able to perform many different functions. In addition to acting as a protective barrier, endothelial cells have been shown to play important roles in control of homeostasis, capillary transport, and, more importantly, regulation of the tone of underlying vascular smooth muscle. The endothelium evokes relaxation of these muscle cells, allowing vasodilation via the chemical factor endothelium-derived relaxing factor (EDRF), which has been...

Iron

Chronic alcoholic patients are often iron deficient because of increased frequency of gastrointestinal bleeding, typically due to alcoholic gastritis or eso-phageal tears from frequent retching and vomiting, or from rupture of esophageal varices in patients with cirrhosis and portal hypertension. The major consequence of iron deficiency is anemia, which may be compounded by the concurrent effects of folate and pyridoxine deficiencies. Conversely, increased exposure to iron, e.g., from cooking...

Mercury

Mercury is a metal that is present in the environment from natural and man-made sources (e.g., coal-burning or other industrial pollution). It is converted primarily by microorganisms to a more toxic form, methylmercury, which is bioaccumulated in the aquatic food chain, reaching it highest levels in large, longer living predatory fish. Among humans, the sole source of exposure to methylmercury is the consumption of fish and sea mammals. Methylmercury is neurotoxic and accumulates in the brain...

Crohns Disease

Crohns' disease is a chronic inflammation that can involve any part of the gastrointestinal system from the mouth to the anus. In the small intestine, Crohns' disease typically affects the ileum however, other parts of the small intestine can be affected. It produces a segmental, full-thickness inflammation, with formation of fissures and abscesses, fistulas, and fibrotic stenoses, and it may follow a chronic relapsing course. The cause of Crohns' disease is unknown, although several hypotheses...

How Does Mercury Contaminate Food

The primary portal of mercury contamination of food is via its industrial release into water, either fresh or salt water, and its conversion to methyl mercury by methanogenic bacteria. As the marine life takes up the methyl mercury, it works its way into the food chain and is ultimately consumed by humans. This is the scenario that occurred following the release of inorganic mercury from an acet-aldehyde plant into Minimata Bay in Japan in 1956 and 1965 and is responsible for the so-called...

Interactions Affecting Transport Metabolism and Excretion

The biological actions of nutrients and drugs can be synergistic or antagonistic, occur at different times after exposure, and affect a variety of target tissues. Some of the most common mechanisms are as follows. Alterations in drug transport Drugs circulate in the bloodstream as free compounds or bound to other constituents, usually proteins. Drugs vary greatly in their propensity to bind to circulating proteins, covering virtually the entire spectrum from 0 to 100 . For a given drug, the...

Effect of Malnutrition on the Course of Tuberculosis

To the extent that cellular immune function affects recovery from TB, one might expect malnutrition to retard or impair the response to treatment. The adverse consequences of malnutrition on the course and outcome of TB disease have been well documented. Malnutrition increases the risk of death in TB patients nearly twofold. Among approximately 1200 patients with TB followed prospectively, 10.9 of patients with moderate to severe malnutrition died in the first 4 weeks compared to 6.5 of...

Children without Recognizable Pathology

Obese prepubertal children are relatively tall for age (many in the upper quartile and most in the upper half of the population distribution for height). Advanced growth may be associated with advanced maturity of bones (advanced bone age), early onset of puberty, and cessation of growth with only average stature in adult life. However, some children remain tall and obese into adult life, and others slim dramatically with the adolescent growth spurt. It is not clear whether obesity drives...

Associated Disorders

Dermatitis herpetiformis This is characterized by an extremely pruritic papulovesicular eruption, which usually occurs symmetrically on the elbows, knees, buttocks, and back. About 80 of patients with dermatitis herpetiformis have small intestine histology indistinguishable from celiac sprue. The diagnosis is established by skin biopsy demonstrating granular IgA deposits in areas of normal appearing skin. A majority of patients with the skin lesion who undergo small bowel biopsy have intestinal...

Effects on the Respiratory System

In caffeine-naive subjects, a dose of 4mgkg_1 increases the mean respiratory rate. This effect is not found in chronic caffeine ingestion. Several mechanisms have been suggested, such as an increase in pulmonary blood flow, an increased supply of air to the lungs due to the relaxation of bronchiolar and alveolar smooth muscle, an increase in sensitivity of the medullary respiratory center to carbon dioxide, stimulation of the central respiratory drive, an improved skeletal muscle contraction,...

Supplementation and Fortification

The serious international problem of iron deficiency has been met with poor success by supplementation and fortification efforts. Both approaches suffer from difficulties in delivery and acceptance. Supplements that readily ionize into the ferrous form, such as ferrous sulfate, ferrous fumerate, or ferrous glu-conate, are highly bioavailable but may cause gastrointestinal discomfort. Iron injections are poorly tolerated and can result in serious infections. Because daily supplementation reduces...

Measurement of Blood Levels

A variety of assays have been developed to quantify blood homocysteine levels, with those employing high-pressure liquid chromatography perhaps being the most common. These assays have proven to be relatively accurate and precise (coefficients of variation less than 10 ), and are relatively simple and quick to perform. The development of such assays in the 1980s was the technological breakthrough that spurred the exponential increase in homocysteine-related research over the last 15-20 years...

Overfeeding

Overfeeding usually results from overestimation of caloric needs. Overestimation occurs when actual body weight is used, such as in critically ill patients with significant fluid overload and in obese patients. Indirect calorimetry can be used to quantify energy requirements. Estimated dry weight should be obtained from preinjury records or family members. Adjusted lean body weight can also be calculated. Clinically, increased oxygen consumption, increased carbon dioxide production, fatty...

Choline Homocysteine and Folate are Interrelated Nutrients

Choline, methionine, methyltetrahydrofolate (methyl-THF), and vitamins B6 and B12 are closely interconnected at the transmethylation metabolic pathways that form methionine from homocys-teine. Perturbing the metabolism of one of these pathways results in compensatory changes in the others. For example, as noted above, choline can be synthesized de novo using methyl groups derived from methionine (via S-adenosylmethio-nine). Methionine can be formed from homocys-teine using methyl groups from...

Nutrition for Training

The training load of athletes varies greatly between individuals, depending on the nature of the sport and the level of competition, and it also varies over time in relation to the competitive season. Training may consist of high-intensity resistance training, brief but intense sprints, prolonged moderate intensity efforts, or technical work. Each places different demands on the muscles, cardiovascular system, and other tissues, and each has different energy requirements. The aim of training is...

Compartmental Model

An overall integration of these autoregulatory control systems in the regulation of body weight and body composition during a cycle of weight loss and weight recovery is discussed with the help of a schematic diagram presented in Figure 4. This diagram embodies the finding that the control of body energy partitioning between protein and fat is an individual characteristic that is, individuals vary in their partitioning characteristic (Pc) during weight loss and weight recovery and takes into...

Macronutrient Demands Protein

The idea that protein requirements are increased by physical activity is intuitively attractive, and highprotein diets are a common feature of the diets of sportsmen and women. The available evidence shows an increased rate of oxidation of the carbon skeletons of amino acids during exercise, especially when carbohydrate availability is low. Protein contributes only about 5 of total energy demand in endurance exercise, but the absolute rate of protein breakdown is higher than at rest (where...

Salt and Disease

The Roman word from which the name 'salt' is derived is Salus, Goddess of Health. Gandhi argued that salt was ''essential for human well being, specially in a poor country like India where its inhabitants eat vegetables and rice which contain low salt.'' However, although its name evokes health, over the years a long-term excess intake of salt has come to be recognized as a major cause of hypertension and thus a risk for stroke and coronary heart disease. An excess of dietary salt may also...

High Risk Groups in Present Day Society

Today, the most high-risk group for development of pellagra signs and symptoms in Western society is chronic alcoholics, whose diets are often poor, and in addition are subject to liver damage from alcohol abuse and its cellular toxicity. Certain forms of psychosis, including depression and schizophrenia, are associated with abnormalities of the tryptophan metabolism pathways, including those involved in the formation of 5-hydroxytryptamine (serotonin) and 5-hydroxytryptophan in the central...

Info

Figure 1 Average weight loss achieved in the lifestyle intervention of the Diabetes Prevention Program. Few lifestyle treatment programs provide follow-up beyond 1 or 2 years. One study reported that at 5-year follow-up 13 of participants remained > 5 kg below their baseline weight. Likewise, 22 of participants were > 5 kg below baseline weight at 5 years in another lifestyle intervention. These studies may underestimate the prevalence of successful long-term weight loss because they are...

Encephalopathy

Several neurological effects have been attributed to aluminum intoxication. In weanling rats, dietary aluminum fed at high levels to their dams has been demonstrated to delay brain maturation. This effect has not been described in man. Aluminum-induced impairment of cognitive function following the occupational exposure of gold miners to inhaled aluminum, the exposure of members of the general public to ingested aluminum sulfate, and, recently, exposure of workers and ex-workers in the aluminum...

Advantages and Limitations of Anthropometric Measurements

Anthropometric measurements are noninvasive. Compared with other methods of assessing nutritional status, the measurements are quick and easy to make using relatively cheap and simple equipment. They can be made by relatively unskilled people. Anthropometric measurements cannot identify protein and micronutrient deficiencies, detect small disturbances in nutritional status, nor identify small changes in the proportions of body fat to lean body mass. Some anthropometric measurements may not be...

Toxicity of Systemic Aluminum

The toxicity of aluminum has been extensively reviewed both by WHO and by the US Department of Health and Human Services. Exposure to aluminum at environmental levels produces no known adverse effects in man. There is little evidence to suggest that aluminum may produce adverse effects under conditions of chronic, excess, occupational exposure. Under conditions of high medical exposure, resulting in large aluminum body burdens, the metal is toxic. Aluminum intoxication is characterized by...

The Effects of Feeding on Blood Glucose Glucose

Glucose and the two lesser dietary monosaccharides, fructose and galactose, enter the circulation through the intestinal mucosa. The speed with which glucose can be absorbed is limited by the rate of transfer from the intestine but rarely exceeds 50 g (0.28 mol) per hour. This comparatively massive influx of glucose into a pool of less than 20 g ordinarily produces a remarkably small perturbation in blood glucose because the rate of removal from the glucose pool increases to match glucose...

Practical Aspects of Meeting the Nutrient Needs of Infants

Adequate amounts of breast milk meet the nutrient needs of most infants for the first 6 months of life. However, there is not universal agreement on the optimal duration of exclusive breast feeding and the precise timing or the order of introduction of complementary foods. Internationally, recommendations from most health agencies state that the ideal feeding of infants is exclusive breast feeding for the first 6 months of life with appropriate introduction of foods from 6 months onward...

Postreproductive Age 49 Years

There are no reports on nutrition interventions for older people in developing countries, successful or otherwise. At best, they are covered in food security projects targeted at the household level, although the focus is generally on maternal and child nutrition. This age group deserves more attention, especially in areas with a high prevalence of HIV, where older people often play a key role in sustaining the household. See also Adolescents Nutritional Problems. Anemia Iron-Deficiency Anemia....

Milk Intolerance Lactose Intolerance

The majority of children can tolerate lactose during a diarrheal episode. A small proportion of children with diarrhea may not be able to digest lactose and are therefore not tolerant of milk- and lactose-containing formulas. This is more likely to occur among young children who only receive animal milk or formula in their diet and who have persistent diarrhea, and it rarely occurs in children on a diet of breast milk. In a lactose-intolerant child, milk- and lactose-containing formulas result...

Regulation of Milk Synthesis Secretion and Ejection

Milk volume production is a primary indicator of lactational function the most precise methods for measuring the volume of milk produced involve weighing infants before and after each feed for 24 h or longer or using an isotope dilution technique with stable isotopes. Clinically, the amount of milk that can be expressed with a breast pump or the change in infant weight after a single feed can be used as a rough index. The volume of milk secreted by women exclusively breast-feeding a single...

Paracellular Transport Pathway V

Pathway V (Figure 2) involves passage of substances between epithelial cells rather than through them, and for this reason it is designated the paracellular pathway. During full lactation the passage of even low-molecular-weight substances between alveolar cells is impeded by the gasket-like tight junction structures that join the epithelial cells tightly, one to another. During pregnancy, with mastitis and after involution the tight junctions become leaky and allow components of the...

Zinc Deficiency

Zinc deficiency is associated with impaired growth and maturation. Zinc deficiency is common in those with frequent diarrhea since zinc concentrations in gastrointestinal secretions are high. Nevertheless, there is little consistent population evidence that children who show recurrent acute diarrhea or who have prevalent growth faltering are improved by zinc supplementation. Supplementation of children with diarrhea in zinc-deficient environments may reduce the duration of diarrhea and thus the...

Aluminum Deposition in Tissues

Most metals are deposited to a much greater extent than average in a few organs liver, kidneys, and skeleton. However, the proportion of the total body burden deposited in these is variable and depends on many factors, including the chemical properties of the ion and the age, sex, and metabolic status of the individual. The major site of deposition of aluminum is the skeleton. Skeletal deposits of aluminum have been demonstrated in normal bone using chemical analysis and are easily detected in...

Rationale for Recommended Nutrient Intakes

Recommendations on dietary nutrient intakes for lactating women by different scientific authorities are typically based on the estimated total amount of each nutrient secreted daily into breast milk, taking into account, where known, the efficiency of milk synthesis and the bioavailability of the nutrient in the maternal diet. This estimate for each nutrient is then added to the recommended nutrient intake for non-pregnant, non-lactating women. The onset of lactation after parturition is...

Health Promoting Phytochemicals

There is much interest in the role of various phyto-chemicals to promote good health and to reduce the risk of various cancers. As with many plant foods, legume seeds contain a number of these types of compounds. Prominent in this group are the iso-flavonoids, such as genistein and daidzein, which are found at high levels in soybeans. Epidemio-logical studies have suggested a positive association between the consumption of soy isoflavones and reduced risk of breast and prostate cancer in...

Evidence for Possible Anticancer Protection by Lycopene

Most of the indications with respect to cancer comes from human studies linking tomato intake, total estimated lycopene intake, and serum or plasma lycopene concentrations to the subsequent development of cancers (Table 5). There is a small amount of evidence from experimental animal studies, for instance, rat and mouse dimethylbenzanthracene-induced mammary tumor studies have supported the hypothesis, as has a model of spontaneous mammary tumor formation in one strain of mice, but many of the...

Iodized Milk

This is particularly important for infants receiving formula milk as an alternative to breast-feeding. An increase in levels from 5 to 10 mg dl has been recommended for full-term infants and 20 mg dl for premature infants. However, breast-fed infants will be iodine deficient if the mother is iodine deficient. Iodized milk has been available in the United States, the United Kingdom and Northern Europe, Australia, and New Zealand as a result of the addition of iodophors as disinfectants by the...

Feeding Behavior

Feeding skills tend to be delayed in the young child with Down's syndrome, but the sequence of the emergence of the skills is the same as that for other children if appropriate learning opportunities are provided. Infants with Down's syndrome have a smaller oral cavity, which makes it easier for liquids to spill from the sides of the mouth. If a child is hypotonic, the tongue is likely to flatten out when the child sucks instead of forming a groove around the nipple, so the child will have a...

The Blood Glucose Concentration

Failure to appreciate the differences between arterial and venous blood glucose is a major cause of the confusion that has surrounded the recognition and diagnosis of hypoglycemia and been responsible for nonhypoglycaemia becoming a common diagnosis amongst those whom Singer and coworkers refer to as, the folk sector. In the fasting subject the concentration of glucose in arterial and venous blood is virtually identical but may differ by as much as 2.5 mmol following ingestion of a...

Soft or Solid Food Energy Density of Diet and Protein and Energy Requirements

A child's diet during the period of diarrhea should not be drastically different from his or her normal healthy diet. Therefore, for children who are currently breast-feeding, they should continue to do so, and for children who are in the weaning period and have a mixed diet, they should continue to have a mixed diet of soft or solid food. If the child on a mixed diet is dehydrated, his or her soft and solid foods should be temporarily stopped for a period of approximately 4 h when he or she...

Brain Function and Hypoglycemia

The brain malfunction to which hypoglycemia gives rise will be referred to as neuroglycopenia. The brain is often thought of as being incapable of using metabolites other than glucose as a source of energy. This is untrue. It has been known for more than 30 years to be able, under certain circumstances including prolonged fasting, to utilize the 'ketone bodies,' 3-hydroxybutyrate and aceto-acetate. Under these circumstances the need for glucose and its supply through gluconeogenesis is...

Preparation for Discharge

Approximately 1 week prior to discharge, preterm infants should be converted to the feeding regimen that will be used at home. Infants who have been fed expressed breast milk should demonstrate the ability to directly breast-feed and or to feed supplemented breast milk or formula from the bottle as needed to gain adequate weight. The infant who weighs less than 2500 g at discharge, especially those infants born at less than 30 weeks' gestation, may require the supplementation of some...

Multination Health and Nutrition Surveys

During the past few decades, the Demographic and Health Surveys (DHS) have been conducted in many countries in all regions of the world. The DHS surveys are nationally representative surveys that include household and individual health and nutrition indicators. The surveys are large, typically 5000 to 30 000 households, and are conducted periodically, often at 5-year intervals. The data included in the survey vary slightly by country (Tables 1 and 2) but typically include as a minimum...

Nutrition and Health in the Urban World

The way in which people eat is a major determinant of their nutritional stores and status, but issues of life style, health and pollution modify and influence the nutriture of individuals and populations. Each of these factors contributes to the distribution of the simultaneous under- and overnutrition states that characterize nutrition transition. Labor market shocks impact on maternal pursuits, child work, and schooling. Rural children have traditionally worked on both household and farm...

In Vitro Bioavailability Technique

Nutrient bioavailability, estimated as absorbability alone, can be measured by various in vitro methods. In vitro methods have obvious distinct advantages in that they are less expensive, rapid, and amenable to high throughput analyses. Often, experimental in vitro methods involve an initial 'digestion phase' where the food is treated with acid and digestive enzymes to simulate the initial steps of food breakdown. The digestion phase is then followed by a second phase wherein the goal is to...

Excessive Intakes

An extensive biological control system limits the occurrence of free ionic iron that can readily participate in toxic, free radical-producing reactions. Large quantities of ingested iron are acutely toxic, and accidental ingestion of medicinal iron preparations is a leading cause of poisoning deaths in young children. Iron supplementation is also associated with gastrointestinal irritation. Iron supplements adversely affect absorption of zinc. Iron absorption is well controlled, but iron...

Mucosal Structure

The lining of the small intestine is remarkably adapted for the function of absorption by increasing the surface area for transmucosal transport at three levels (Figure 1) The inner surface has circular folds, which increases the area by approximately 3-fold. The mucosa projects from the folds into the lumen with finger-like structures called villi approximately 1 mm in length. Villi increase the surface area by an additional 10-fold. The surface of each villus is covered with epithelial cells...

Effects on the Cardiovascular System

Caffeine produces a direct stimulation of myocardial tissue leading to an increase in the rate and force of contraction. This direct cardiac effect can be inhibited by a depressant effect on the heart via medullary vagal stimulation. These opposing effects may explain why bradycardia, tachycardia, or no change can be observed in individuals receiving similar doses of caffeine. The traditional clinical view that caffeine induces arrhythmias in humans has not been confirmed by controlled...

Diet and Physical Activity Behaviors

The WHO analysis identified a number of key dietary and physical activity behaviors, amenable to change, that could conceivably influence energy balance sufficiently to contribute to the prevention of weight gain and obesity. Behaviors that reduced the risk of obesity included regular physical activity, high dietary fiber intake, and possibly breast-feeding and low glycemic index diets. Behaviors that increased the risk of obesity included a high intake of energy-dense foods, a high intake of...

Prevention of Dehydration

Dehydration resulting from nondisease causes can be easily prevented provided that people are inclined to drink and have access to cool, safe sources of fluids. Drink flavoring, beverage temperature, and sodium chloride content are important promoters of fluid intake in active children. Education of athletic coaches, the general public, and health care providers is necessary to increase Table 6 Fluid replacement Summary of recommendations of the American College of Sports Medicine It is...

Parenteral Nutrition

Since the gastrointestinal tract of the preterm infant is immature, substantive enteral nutrition is not possible in the first 2-3 weeks after birth, especially in those infants whose birth weights are less than 1500 g therefore, the preterm infant is dependent on intravenous fluid for the bulk of fluid needs. Parenteral nutrition (PN) is basically the infusion of a nutrient solution into the circulation. Its development has allowed for the provision of nutrients during the time that enteral...

Breast Feeding Initiatives

In response to concerns about the use of infant formula in environments where lack of breast feeding resulted in large numbers of infant who became severely ill or died, a grassroots global initiative took hold in the 1970s to promote international and national efforts to protect, promote, and support breast feeding. These efforts culminated in 1981 with the nearly unanimous adoption by the World Health Assembly (WHA) of the International Code of Marketing of Breast-Milk Substitutes. This...

Global Burden of Diarrhea and Epidemiological Trends

Diarrheal illnesses in young children are among the leading causes of morbidity and mortality in developing countries. Diarrhea is an important cause of morbidity in developed countries as well. In developing countries, children younger than 5 years old suffer 3-10 episodes of diarrhea per year, whereas in developed countries young children have on average 1 or 2 diarrheal episodes per year. The advent of oral rehydration therapy (ORT) and its use in the past three decades have dramatically...

Global Breast Feeding Practices

The most comprehensive data on breast feeding come from the Demographic and Health Surveys conducted with support from the US Agency for International Development. These surveys are nationally representative and conducted throughout the developing world. In a number of countries, multiple surveys permit the analysis of trends. Overall, the data show that although the vast majority of women more than 90 in all countries initiate breast feeding, the duration of exclusive breast feeding is far...

Dehydration and Human Performance

Natives of desert regions have, over the years, habituated to being chronically dehydrated. A study of the desert inhabitants found that they had a curtailed thirst drive that was associated with excretion of low volumes of concentrated urine and a high incidence of kidney disease (kidney stones). When additional water intake (approximately twice normal) was ingested in a subsample of this population, they were able to exercise 10 longer in the desert environment, presumably due to improved...

Everyday Feeding problems

Young children are usually determined to show their independence. This can be frustrating for carers. The children want to do things for themselves yet do not have the skills to succeed. Approaches such as letting young children attempt spoon-feeding whilst their carers feed them unobtrusively from other spoons are 'feeding skills' parents and carers develop. Young children are also easily distracted. It is wise to feed them away from active television sets and brothers and sisters at play if...

Impact of Supplementation

Numerous investigators have explored the benefits of energy and or protein supplementation for pregnancy weight gain and other outcomes. However, relatively few trials have randomly assigned these supplements and used control diets. A statistical analysis was conducted of the 10 such studies that met this criterion in 1995. Most, but not all, of these studies were performed in developing countries. A 5-year controlled trial in The Gambia provided daily prenatal dietary supplements (two...

Breast Milk

Breast milk is a unique bioactive substance that changes composition, within and between feedings and over time, to suit the needs of the growing infant. More than 200 different constituents of breast milk have been identified, many of which have dual roles, and more continue to be discovered as analytic techniques improve. Breast milk includes true solutions, colloids, membranes, membrane-bound globules, and living cells. Its three distinct stages occur when colostrum, transitional, and mature...

Nonhypoglycemia

No account of dietetic treatment of hypoglycemia would be complete without a brief description of 'nonhypoglycemia', which has been described as a controversial illness and epidemic in the US. Clinically, the illness is indistinguishable from (idio-pathic) reactive hypoglycemia, except that the blood glucose level is never pathologically low during symptomatic episodes. Moreover, although transient 'turns' are often a major feature of the illness, only rarely, if ever, does the patient consider...

Long Term Effects of Infant Feeding

Much of the literature on the long-term effects of infant feeding is based on comparison of outcomes associated with human milk versus infant formula feeding. Postulated effects relate primarily to the different composition of human milk versus formula and different energy and nutrient intake by infants. The literature does not provide a clear and consistent picture of the long-term effects of feeding. When effects are found, they tend to be modest. Before discussing the results of these...

Dietary Interventions

The concept that specific dietary components may adversely affect behavior has rested on three hypotheses The idea that food might have an adverse effect on behavior was first raised in 1922 by Shannon. This concept was further elaborated in 1947 by Randolph in his description of the 'tension fatigue syndrome,' a behavioral extension of the vomiting reaction to milk proteins, and was also promoted by Speer. Their theory suggested that some children have atypical allergic reactions to various...

Introduction of Dietary Therapy

Infant formulas for PKU come in a powdered form and are mixed with water and taken as a substitute for regular infant formula or breast milk. In some clinics, only phenylalanine-free formula is given for a few days so that blood phenylalanine will quickly decrease to an acceptable level. A prescribed amount of breast milk or standard infant formula, however, should be shortly introduced into the diet. Whole protein is needed to meet phenylalanine requirements and prevent phenylalanine...

Breast Feeding Recommendations

Both the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) recommend exclusive breast feeding for 6 months and continued breast feeding together with provision of safe, appropriate, and hygienically prepared complementary foods until 2 years of age or beyond. The American Academy of Pediatrics Section on Breastfeeding also recommends exclusive breast feeding for 6 months. Breast feeding is defined as exclusive if breast milk is the sole source of infant nutrition...

Histidine

Histidine is the precursor for histamine, which is important for the immune system by mediating growth and functionality of immune cells. Excessive release of histamine from mast cells induces the clinical signs of allergy (dilation of capillaries and larger blood vessels, increased capillary permeability and swelling, itching, and anaphylactic shock). These phenomena are effected via the H1 receptor, which is found in smooth muscle cells of the vascular wall and bronchi, among others....

Carcinogenicity in Animals

AFB1 is a potent liver carcinogen in many species of animals, including rodents, nonhuman primates, and fish. In appropriate circumstances, dependent on such variables as animal species and strain, dose, route of administration, and dietary factors, significant incidences of tumors have been induced at sites other than the liver, such as kidney and colon. AFB1 has been demonstrated to induce liver tumors in two species of lower primates the tree shrew (Tupaia glis) and the marmoset (Sagui-nus...

Changes in Micronutrient Status

Few studies document the changes in micronutrient status that can be expected from the seasonal changes in dietary quality. In The Gambia both plasma ascorbate and breast-milk ascorbate had seasonal fluctuations connected with fruit and vegetable intake. Carotenoids also showed a three-fold fluctuation, while retinol was unchanged. In another study in undernourished children in The Gambia significant seasonal changes were observed for hemoglobin levels and plasma concentrations of vitamin C and...

Immune function and cancer

The diet is believed to play an important role in the onset of carcinogenesis, and there are a number of carcinogens present in food, including mycotoxins, polycyclic hydrocarbons, and pesticides. Associations have been made between dietary fat intake and morbidity and mortality from breast and colon cancer. Another possible mechanism for the proposed protective effects against cancer of olive oil compared with sunflower oil involves diet-induced alterations in host immune responses. Both the...

Mechanisms of Carcinogenicity

Chemical carcinogens induce neoplasia by a wide range of mechanisms involving either interaction with the hereditary material of the organism or interference with one of the many cellular control systems. The former compounds, known as geno-toxic carcinogens, interact directly with DNA, resulting in a permanent heritable change to a cell following replication (i.e., an altered genotype). In contrast, nongenotoxic (epigenetic) carcinogens do not interact directly with DNA but cause cancer by...

Long Term Regular Exercise Lowers the Risk of Sex Hormone Sensitive Cancers

The amenorrhea and delayed menarche of athletes raised the question Are there differences in the long-term reproductive health of athletes with moderate training compared to nonathletes A study of 5398 college graduates ages 20-80 years, of whom 2622 were former athletes and 2776 were nonathletes, showed that the former athletes had a significantly lower lifetime occurrence of breast cancer and cancers of the reproductive system compared to the nonathletes. More than 82.4 of the former college...

Metabolic Activation of Epigenetic Carcinogens

Since there is no common mechanism describing the action of epigenetic carcinogens, generalizations concerning the effect of metabolism on the activity of chemicals acting by a nongenotoxic mechanism are not possible. The activity of a number of epige-netic carcinogens is reduced as a result of metabolic activation, although in the case of one group of epigenetic carcinogens that produce renal tumors in the rat by binding to and preventing the degradation of a specific kidney protein,...

Nonmalignant Complications of Celiac Disease

Nonmalignant complications of celiac disease include ulcers and structuring within the intestine that occasionally may present with small bowel obstruction and or bleeding, and recurrent acute pancreatitis as the result of inflammation, probably of the sphincter of Oddi. Nongastrointestinal complications are usually the consequence of malnutrition or specific deficiencies. However, others such as neurological problems including ataxia, peripheral neuropathy, or dementia are of uncertain...

Osteoporosis

The role of lactose maldigestion, calcium intake, and osteoporosis has been studied. Osteoporosis and osteoporitic fractures are major public health problems. The role of lactose maldigestion and osteoporosis remains unsettled. For example, minority populations consuming small amounts of milk should be at greater risk for osteoporosis. Nevertheless, African American and Hispanic populations in the United States appear to have a lower risk of developing osteoporosis. Caucasian and Asian women...

Birth Weight and Adult Disease

Further evidence for the role that the early life environmental influences play in establishing the risk for disease came in the early 1990s when studies conducted by Barker and colleagues in a large cohort of men and women from Hertfordshire, UK revealed strong correlations between low birth weight and a high prevalence of metabolic diseases in later life (Table 1). Although not universally accepted, numerous epidemiological studies completed throughout the world, including other parts of the...

Data Analysis and Limitations

Whatever dietary assessment measure is used, the utility of the data is dependent on the translation of reported food intake to nutrient intake. This requires detailed and accurate nutrient databases. The US Department of Agriculture has the most extensive nutrient database in the world, allowing for good estimation of dietary intakes in the US. Most other countries have not conducted this level of food composition analysis for their own locations. Therefore, most databases used throughout the...

Issues in Survey Design

National data on food availability is generally collected with food balance sheets. While not a survey in the formal sense, this is a collection of data from the food sector regarding wholesale distribution. After adjusting for expected losses and wastage, these data are compared to nutrient values and then to the size and composition of the population to calculate per capita nutrient availability. Because this is a crude assessment, it generally does not account for all losses or waste and...

Biochemistry and Metabolic Functions

Only two reactions in humans and other animals are known to require cobalamin (Figure 2). One is iso-merization of methylmalonyl coenzyme A (CoA), which requires deoxyadenosylcobalamin, is catalyzed by the enzyme methylmalonyl CoA mutase, and is Figure 2 Reactions in humans and other animals known to require cobalamin. Figure 2 Reactions in humans and other animals known to require cobalamin. mitochondrial. The other reaction is the transmethy-lation of homocysteine by 5-methyl-tetrahydrofolate...

Effects on Renal Functions

In humans, the administration of a single dose of 4mgkg_1 caffeine increases the urinary excretion of sodium, calcium, magnesium, potassium, chloride, and urine volume. The mechanism of this mild diuresis has been attributed to an increase in renal blood flow, an increased glomerular filtration, and a decrease in tubular reabsorption of sodium ions and other ions. Although these effects appeared more pronounced for a higher acute dose of 10mgkg_1, a review concluded that caffeine consumption...

Dietary Fiber and the Etiology of Cancers Colon and Rectum

This is one long-standing association that has been surprisingly problematic. Early studies on native Africans who consumed an unrefined diet showed them to have a very low incidence of this cancer. Although subsequent studies have shown a negative association between greater fiber intake and lowered risk, it has proved to be relatively weak. Indeed, in one US study there was no real association between fiber intake and cancer susceptibility. Some of the loss of significance seen in this...

Bone Disease

The development of osteopenia is another complication that is common with long-term PN support. The reasons are multifactorial and include relative immobility, inability to provide adequate calcium and phosphorus with solubility limitations, and hypercalciuria. It has also been suggested that the dose of vitamin D in the multivitamin preparation may contribute to bone disease. Excessive vitamin D may suppress parathyroid hormone secretion and directly cause bone resorption. Although aluminum is...

Maternal Nutrition and Fetal Origins of Adult Metabolic Diseases

Assessing the impact of maternal nutrition on health of the offspring in humans is difficult. However, investigations involving offspring conceived during conditions of famine have provided direct evidence of the effects that maternal nutrition during gestation and lactation has on the overall health of the adult offspring. The Dutch famine, which occurred in the western part of the Netherlands at the end of World War II, only lasted around 5 months from late November 1944 to early May 1945,...

The Enteric Nervous System and Gastrointestinal Motility

The enteric nervous system (ENS) operates both in conjunction with and independent of the peripheral nervous system. As discussed previously, nerve plexi exist within the bowel wall, with Auerbach's plexus sandwiched between longitudinal and circular muscle layers, and Meissner's plexus located more medially in the submucosa. The ENS is the largest component of the autonomic nervous system, based on nerve cell number. Interstitial cells of Cajal, a cell type unique to the alimentary tract, are...

Exercise and Physical Activity

The term 'physical activity' refers to bodily movement produced by skeletal muscle that results in energy expenditure it thus includes activities of daily living, as well as leisure activity from sport and exercise. The term 'exercise' refers to planned or structured bodily movements, usually undertaken in leisure time in order to improve fitness (e.g., aerobics), while 'sport' is physical activity usually in structured competitive situations (e.g., football). Physical activity at recommended...

Definitions

The word 'allergy' is frequently misused and applied indiscriminately to any adverse reaction, regardless of the mechanism. An allergic response is a reproducible adverse reaction to a substance mediated by an immunological response. The substance provoking the reaction may have been ingested, injected, inhaled, or merely have come into contact with the skin or mucous membranes. Food allergy is a form of adverse reaction to food in which the cause is an immunological response to a food. The...

Chronic Liver Disease

Chronic liver disease is often accompanied by nutritional deficiencies. The goals of nutritional management are to provide adequate energy and protein to prevent energy deficits and protein catabolism and to Table 4 Management of chronic liver failure in children Nutritional support Energy intake, 120-150 (recommended daily amount) Carbohydrate, 15-20 g kg day Protein, 3-4 g kg day Fat, 8g kg day (50 medium-chain triglyceride) Fat-soluble vitamins Ascites spironolactone (3mg kg), furoseimide...

Medical History

The medical history for nutritional assessment is no different from a general medical history, in which familial and past and present environmental factors and their possible association with specific diseases or disease risk are considered. For the purpose of nutritional assessment, this information will be used to determine if any nutritional finding or complaint may be caused by an underlying medical condition, particularly one that remains unrecognized at the time of the examination....

Micronutrients

Main sources of micronutrients are breakfast cereals, milk, bread, chips potatoes, and eggs. Surveys that report comparisons between intakes and recommendations have found satisfactory intakes for most micronutrients when means are considered. Intakes of vitamins B1, B2, B6, B12 C, and niacin greatly exceeded RNIs in the NDNS, perhaps reflecting high protein intakes and the fortification of popular foods such as breakfast cereals, bread, and beverages. Even folate, a problem nutrient in earlier...

Provocation Tests

A provocation test may be useful to confirm a history of allergy. An example might be a child who developed wheezing and urticaria minutes after eating a rusk that contained, as its main ingredients, wheat and cows' milk protein. To determine which component, if any, caused the reaction, oral challenges with individual components can be conducted. However, the results of provocation tests cannot prove that improvement in a disease has been caused by food avoidance. For example, a child with...

Benefits of Breast Feeding

Breast feeding contributes to both maternal and infant nutrition and health through a number of important mechanisms. It provides a complete source of nutrition for the first 6 months of life for normal, full-term infants and provides one-half and one-third of energy needs for the second half of the first year and the second year of life, respectively. It also contributes significantly to protein and micro-nutrient requirements. Numerous studies have shown that during illness, whereas intake of...

Clinical Manifestations Diagnosis and Treatment

The classic symptom of ulcer is dyspepsia, a burning epigastric pain usually occurring 2-3 h after meals and at night (between 11.00 p.m. and 2.00 a.m.) when acid secretion is maximal. Relief often occurs with ingestion of food and alkali. Although suggestive of peptic ulcer, dyspepsia is not a sensitive or specific measure of peptic ulcer. Only about 50 of DU patients have the typical symptom of dyspepsia. Some ulcer patients develop a stomach that is easily irritated by food, mechanical...

Best Practices to Prevent Osteoporosis

In summary, several practices can be adopted to assist in the prevention of osteoporosis. From a nutritional standpoint an emphasis should be made on adequate intakes of calcium, vitamin D and a balanced diet that meets the requirements of other essential bone-related minerals and nutrients (detailed in Table 1). A healthy body weight should be achieved and maintained throughout the life cycle. Age-appropriate physical activity and exercise programs should be promoted to maintain fitness,...

Phosphate in Health and Disease

Phosphate balance in adults is almost always zero, in contrast to calcium balance, which is usually negative, because of the effective action of PTH on renal tubules to block Pi reabsorption. In late life, however, intestinal phosphate absorption decreases and the serum phosphate concentration declines. These physiological decrements may contribute to disease, especially to increased bone loss and osteo-penia or more severe osteoporosis. Typically, these changes in Pi balance are also...

Nutrient Gene Interactions

Optimal nutrition is needed to supply the necessary substrates for bone however, other parameters also influence the impact of a given nutrient on bone health. A substantial amount of bone mineral acquisition (up to 80 ) is genetically determined. An individual's ability to utilize a given nutrient intake is influenced by his or her genetic makeup. Many candidate genes have been associated or linked with the risk of osteoporosis or fracture, including genes coding for hormones (PTH), receptors...

Motivation for Micronutrient Supplement

People choose to use micronutrient supplements for various reasons. Survey data indicate that many individuals decide to take micronutrient supplements based on advice from health professionals, family, and friends. A majority of supplement users regard micronutrient supplements as 'insurance' against general poor health or becoming ill, even though they recognize that scientific evidence for this belief may be lacking. Generally, people report that they use supplements either because they...

Consequences of Mg Deficit and Implications in Various Metabolic Diseases

Mg deficit causes neuromuscular manifestations, including positive Chvostek and Trousseau signs, muscular fasciculations, tremor, tetany, nausea, and vomiting. The pathogenesis of the neuromus-cular irritability is complex, and it implicates the central and peripheral nervous system, the neuromuscular junction, and muscle cells. Mg deficit perturbs Ca homeostasis and hypocal-cemia is a common manifestation of severe Mg deficit. Impaired release of parathyroid hormone (PTH) and skeletal end...