Urolithiasis Kidney Stones

Although modest overindulgence in purine-rich food by normal subjects does not precipitate gout, it can predispose to uric acid lithiasis. Uric acid stones are relatively common in countries where the consumption of nucleic acid-rich beverages and food is high and in hot climates if insufficient fluids are consumed. Health foods such as yeast tablets, Spirulina, or supplements containing nucleotides also contribute to uric acid lithiasis. A number of compounds, such as vitamin C, increase uric...

Liver in Specific Hepatobiliary Disorders Hepatocellular Diseases

Alcoholic liver disease The term 'alcoholic liver disease' refers to a spectrum of types of hepatic injury associated with continuous alcohol ingestion, ranging from alcoholic fatty liver to alcoholic stea-tohepatitis, fibrosis, and cirrhosis. Nutritional disturbances in alcoholics are an important cause of morbidity and mortality all classes of nutrients are affected. Anorexia leads to decreased food intake and subsequent protein-calorie malnutrition. Maldigestion and malabsorption can occur...

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...

Copper

X Xu, S Pin, J Shedlock and Z L Harris, Johns Hopkins Hospital and School of Medicine, Baltimore, MD, USA 2005 Elsevier Ltd. All rights reserved. Transition metals occupy a special niche in aerobic physiology as facile electron donors and acceptors, they are essential participants in oxidation reduction reactions throughout the cell. These unique properties of transition metals are largely dependent on the electronic configuration of the electrons in the outer shell and in the penultimate outer...

Macronutrients Energy Carbohydrate Fat Protein and Amino Acids

Energy The estimated energy requirement (EER) for infants was derived by summing predicted total energy expenditure (TEE) and energy deposition for growth. Because the energy needs for growth decelerate with advancing age, an equation for EER was established for three age intervals during the first year of life (Table 1). The TEE is calculated using an equation (Table 1) based on energy expenditure measured by doubly labeled water and adjusted for weight of the child. The EER is then the sum of...

Principles of Dietary Management of Diabetes

Assessment The first step for planning an appropriate nutrition plan is a full assessment of the diabetic patient. Topics covered in the nutritional assessment are included in Table 1. Individualization Individualization is a cardinal principle of medical nutrition therapy for diabetes, facilitating individual lifestyle and behavior changes that will lead to improved metabolic control. Since no one diet fits all, the standard, printed diabetic diet is inadequate. Rather, people with diabetes...

Vitamin A Supplementation

The use of supplements to eliminate vitamin A deficiency is a notable success, with remarkable advances achieved within the past decade. Although the elimination of vitamin A deficiency by year 2000 was one of the goals set at the World Summit for Children in 1990, little progress was evident at mid-decade. Clinical vitamin A deficiency was estimated to affect approximately 3.3 million children younger than the age of 5 years in 1995, with an additional 100 million subject to subclinical...

Nitrogen Balance

Nitrogen balance studies were initiated in the mid-nineteenth century by Carl Voit, and such studies have been central to the definition of protein requirements. The aim of nitrogen balance studies is simple to define the relationship between intake and all losses (urinary, fecal, and surface mainly sweat, skin, hair, breath ammonia, nail clippings, etc.) so that the intake that allows equilibrium and provides for all losses can be identified. Thus, when the intake equals the requirement, As...

Effects of Alcohol on Liver Function

Central to the effects of ethanol is the liver, in which 60-90 of ethanol metabolism occurs. Ethanol displaces many of the substrates usually metabolized in the liver. Metabolism of ethanol by ADH in the liver generates reducing equivalents. ALDH also generates NADH with conversion of acetaldehyde to acetate. The NADH NAD+ ratio is increased, with a corresponding increase in the lactate pyruvate ratio. If lactic acidosis combines with a 3-hydroxy-butyrate predominant ketoacidosis, the blood pH...

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...

Major Contributors of Dietary Saturated Monounsaturated and Polyunsaturated Fatty Acids and Cholesterol

The major types of dietary fats and oils are generally broken down on the basis of animal and plant sources. The relative balance of animal and plant foods is an important determinant of the fatty acid profile of the diet. However, with the increasing prominence of processed, reformulated, and genetically modified foods, it is becoming more difficult to predict the fatty acid profile of the diet on the basis of the animal verses plant distinction. According to the National Health and Nutrition...

Signal Transduction

Phospholipids are substrate molecules for a wide range of lipid-derived signaling molecules, including diacylglycerol (DAG), phosphatidic acid (PA), 20 4n6, eicosanoid products, PAF, and lysophospha-tidic acid, generated by the action of PLA2, PLC, and PLD. The activation of these enzymes is complex, partly because of the large number of isoforms present within a cell and also because of the interdependence and coordination of their regulation. For instance, the bacterial peptide...

Prolonged Fasting

In a normal adult, resting energy expenditure is proportional to lean body mass. Prolonged fasting is associated with a loss of lean body mass and in a reduction in resting energy expenditure. Fourteen to 21 days after commencing a starvation diet there is a 15 reduction in resting energy expenditure. However, at this time there is only a 5 reduction in lean body mass. Clearly, another mechanism contributes to the decreased resting energy expenditure observed in early starvation. A number of...

The Role of Eggs in the Diet

The nutritional contribution of eggs to a diet is determined by the per capita consumption profile of a given country. In countries such as Japan, with the highest per capita egg consumption, eggs play an important role as a source of nutrients, while in countries such as India, with very low per capita consumption, their role is minor. Worldwide there are many misperceptions and myths regarding eggs, which influence consumption patterns (Table 8). Eggs are a nutrient-dense source of many EAA,...

Carbohydrate Malabsorption

Lactose intolerance Lactose intolerance is defined by the occurrence of symptoms due to the inability to digest lactose, the main carbohydrate in milk. These symptoms may include abdominal pain, bloating, diarrhea, or flatulence. Lactose malabsorption is attributed to a relative deficiency of the di-saccharidase lactase. Primary lactase deficiency is a condition in which lactase activity declines after weaning. Secondary lactose intolerance is usually due to mucosal injury associated with a...

Antioxidants Found Within the Human Body

The structures of the human body are exposed continuously to a variety of ROS. Humans have evolved an effective antioxidant system to defend against these damaging agents. Different sites of the body contain different antioxidants or contain the same antioxidants but in different amounts. Differences are likely to reflect the different requirements and characteristics of these sites. Human plasma and other biological fluids are generally rich in scavenging and chain-breaking antioxidants,...

Failure to Thrive

Failure to thrive is failure to gain in height and weight at the expected rate, the expected rate usually being that indicated by charts for height and weight related to age and sex in reference populations. Since it is often easier to measure weight than height in small children and since weight can be lost as well as not gained, whereas height gain can only be absent or slowed, assessment of failure to thrive is frequently made on weight progress alone. Although a child may be low weight for...

The Glutathione Reductase Test

One rather serious drawback of the urinary excretion index for the assessment of riboflavin status is that it is relatively insensitive at low-to-moderate intakes, because the rate of excretion changes slowly and not very predictably with increasing intake in this region. Another important practical drawback is that 24-h urine samples are not easy to collect and excretion rates may fluctuate over short time periods. A more stable index was therefore sought and was identified in the degree of...

Non Nutrient Antioxidants

Plant-based foods contain a multitude of antioxi-dants other than vitamin C and vitamin E. The two major classes of these other dietary-derived antioxidants are the carotenoids and the polypheno-lic flavonoids. There are hundreds of different car-otenoids and thousands of flavonoids, and these compounds give fruits, vegetables, teas, and herbs their wonderful colors in shades of red, orange, yellow, and purple. These compounds are synthesized exclusively in plants and have no known function in...

Models and Tracer Methods for the Study of Protein Turnover

Studies of protein turnover have utilized isotope tracer techniques, radioactive tracers (14C and 35S) in animals, and stable isotopes (13C, 15N, and 2H) in humans. Most studies utilize simplified models the simplest and most widely used (Figure 2) is based on the measurement of the amino acid flux through the plasma amino acid pool. An example is the primed continuous intravenous infusion of 13C-1-labeled leucine. During the infusion, the tracer isotopic enrichment is diluted by unlabeled...

Requirements and High Intakes

As already mentioned, the ultratrace elements other than selenium and iodine are a disparate group in terms of their possible requirement or nutritional importance for human health and well-being. Although molybdenum has known essential functions, it has no unequivocally identified practical nutritional importance. The other 14 ultratrace elements discussed here have been suggested to be essential based on circumstantial evidence. This evidence is presented below along with some indication of...

Route of Feeding

Wherever possible, the enteral route should be used. The American Gastroenterological Association has strongly endorsed this view and stated that routine parenteral nutrition is contraindicated if the enteral route is available. Nasogastric, nasojejunal, and percutaneous enteral access tubes have all been used successfully when feeding is introduced as soon after burn injury as possible. Jejunal feeding is associated with a higher success rate than gastric feeding and may be continued even in...

Energy Accretion in the Fetus

Fat has a high energy content (9.5kcalg-1) and a very high carbon content (approximately 78 ). Thus, differences in fetal fat concentration among species lead to large differences in calculated energy accretion rates and carbon requirements of the fetal tissues for growth. The energy concentration of nonfat dry weight is fairly consistent across species and also within species at different developmental stages, indicating that the ratio of protein to nonprotein substrates in the tissues is...

Assessment of Protein Quality

The most accurate assessment of protein quality of foods for humans is through clinical or metabolic studies that measure nitrogen balance. A fixed amount of protein is fed to a group of individuals until a steady state is reached. At that point, excreta are collected and analyzed for their nitrogen content, and integumental nitrogen losses are generally estimated at approximately 5mgNkg 1 to calculate NB as follows NB IN UN FN IntegN (See abbreviations in Table 1). Measurements are repeated...

Digestibility

The digestibility of a protein is a measure of the amount of protein available from it for absorption after digestion this is usually obtained from estimates of dietary nitrogen and fecal and urinary nitrogen. Digestibility is different from the other measures of protein quality, such as the amino acid or chemical scores and biological value, which respectively represent the essential and nonessential amino acid composition of the protein and the proportion of available nitrogen retained for...

Etiology

As with anorexia nervosa, the picture of development is complex and multifactorial. There is no single cause of bulimia nervosa. Rather, a variety of psychological, biological, and social factors are involved in the emergence of the disorder. Although etiology is diverse, it has much in common with the forces responsible for anorexia nervosa and is clarified by looking at the groups of people most at risk. Overall, the balance of etiological factors is in favor of psychological and social...

Ecology of Iodine Deficiency

There is a cycle of iodine in nature. Most of the iodine resides in the ocean. It was present during the primordial development of the earth, but large amounts were leached from the surface soil by glaciation, snow, or rain and were carried by wind, rivers, and floods into the sea. Iodine occurs in the deeper layers of the soil and is found in oil well and natural gas effluents, which are now a major source for the production of iodine. The better known areas that are leached are the...

Classification of Serum Lipoproteins According to Their Electrophoretic Mobilities

With the development of techniques to separate proteins according to their electrophoretic behavior, it could be demonstrated that most of the lipid present in serum was associated with proteins migrating with a1- and -globulin mobilities. This resulted in the first classification of lipoproteins as a1- and -lipoproteins. The ratio of lipid to protein on the -lipoproteins was approximately 1 1, whereas the -lipoproteins had a greater relative content of lipids. Application of more advanced...

Dietary Reference Intakes for Infants

For infants, evaluation of evidence to establish the DRIs consistently revealed a paucity of appropriate studies on which to base an Estimated Average Requirement (EAR) or UL. A Recommended Dietary Allowance (RDA) could not be calculated if a value for the EAR was not established, in which case the recommended intake was based on an Adequate Intake (AI). The nutrient recommendations for infants from birth through 6 months of age for all nutrients except for energy and vitamin D were set as an...

Innate Nonspecific versus Adaptive Specific Immunity

Immune responses can be divided into two broad categories innate and adaptive. Innate immune responses are also called nonspecific since they do not discriminate between most foreign substances. They are also not enhanced by previous exposure to a pathogen. In contrast, adaptive (also called acquired) immunity is highly specific to a particular pathogen and becomes more rapid and stronger with subsequent exposure to an antigen. Upon the initial encounter with an antigen, the adaptive immune...

Vitamin A Homeostasis and Activation into atRA

Intestinal absorptive cells absorb dietary carotenoids and retinol during the bile-acid-mediated process of lipid absorption. Within the enterocyte, central cleavage by a soluble 63-kDa carotene 15,15'-monooxy-genase catalyzes the principal route of carotenoid metabolism (Figure 4). Carotene 15,15'-monooxy-genase belongs to the same gene family as RPE65 (the mouse proteins have only 37 amino acid identity, however), suggesting a family of proteins enzymes dedicated to transport metabolism of...

Chemistry and Biochemical Functions

Folic acid (Figure 1) consists of a pterin moiety linked via a methylene group to a para-aminobenzoylgluta-mate moiety. Folic acid is the synthetic form of the vitamin its metabolic activity requires reduction to the tetrahydrofolic acid (THF) derivative, addition of a chain of glutamate residues in 7-peptide linkage, and acquisition of one-carbon units. substituted pterin > -Figure 1 Structural formula of tetrahydrofolate (THF) compounds. In tetrahydrofolic acid R H other substituents are...

Food Folklore Today

While some food folk beliefs continue to be passed down from generation to generation, others have been discarded over the years, and new ones have been introduced. Today, food folklore is spread not only by word of mouth from person to person, but also to large numbers of people simultaneously via the mass media and the Internet. The growing popularity of alternative therapies, organic products, and functional foods has led to the development of new food folklore and increased the popularity...

Fish Proteins

Both finfish and shellfish are highly valuable sources of proteins in human nutrition. The protein content of fish flesh, in contrast to the fat content, is highly constant, independent of seasonal variations caused by the feeding and reproductive cycles, and shows only small differences among species. Table 4 summarizes the approximate protein contents of the various finfish and shellfish groups. Fatty finfish and crustaceans have slightly higher than average protein concentrations. Bivalves...

Resistant Starch Definition

In 1992, a concerted action of European researchers defined resistant starch as ''the sum of starch and the products of starch degradation not absorbed in the small intestine of healthy individuals.'' This concept completely changed our understanding of the action of carbohydrates in the diet because up until the early 1980s, it was thought that starches were completely digested and absorbed in the human small intestine. Three important considerations are attached to this physiological...

Circumstances Leading to Deficiency

The fact that normal humans have a requirement for biotin has been clearly documented in two situations prolonged consumption of raw egg white and parenteral nutrition without biotin supplementation in patients with short bowel syndrome and other causes of malabsorption. Based on lymphocyte carboxylase activities and plasma biotin levels, some children with severe protein-energy malnutrition are biotin deficient. Investigators have speculated that the effects of biotin deficiency may be...

Measurement of Vitamin C Status Biochemical Tests for Adequacy and Deficiency

In species (such as humans) that cannot synthesize vitamin C in their bodies, the vitamin concentration in tissues and blood compartments (plasma, erythro-cytes, and white blood cells) varies characteristically with the dietary intake of the vitamin. Since the blood-compartment concentrations mirror the concentrations in most other cells and tissue compartments, tissue vitamin C status can be monitored by measuring the concentration in plasma or blood, even though the blood concentrations are...

Diagnosis

There is something in the region of 100 causes of hypoglycemia but all, apart from exogenous (or iatrogenic) insulin overdose, are uncommon. Some of the most important causes of recurrent hypogly-cemia are listed and briefly described in Table 1. Simultaneous occurrence of symptoms, a measured low blood glucose concentration, and relief from intravenous glucose are a sine qua non for diagnosis. Differentiation is seldom simple and always rests heavily upon the results of laboratory data of...

Absorption Transport and Storage Status Measurement

A considerable proportion of the pantothenic acid (vitamin B5, see Figure 1) that is present in food eaten by animals or humans exists as derivatives such as coenzyme A (CoA) and acyl carrier protein (ACP). Compared with the crystalline vitamin, only about half of the vitamin in food is thought to be absorbed. The pantothenic acid in its derivatives in food is largely released as free pantothenic acid or pantetheine by pancreatic enzymes, and is then absorbed along the entire length of the...

Pathological ketosis

The major example of pathological ketosis is of course insulin-dependent or type 1 diabetes. Essentially the changes in this condition are similar to those that occur during fasting, but they are more pronounced. Insulin is absent or very low in the plasma and therefore there is no antagonistic action to restrain the opposing hormones, adrenaline, nor-adrenaline, and glucagon. Consequently, lipolysis in adipose tissue is greatly stimulated and plasma fatty acids increase to high levels. The...

Improvement of Protein Quality Amino Acid Profile

The amino acid profile of a food or diet can be improved by increasing the amount of constituent amino acids in its proteins, adding specific amino acids, or combining foods in proportions that result in a better amino acid pattern. Genetic handling This has resulted in cereals with higher contents of the amino acids that limit their protein quality. For example, varieties of Opaque-2 corn have approximately 50 more lysine and 35 Table 7 Calculation of protein quality of a mixed diet based on...

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...

Assessment of Thirst

In humans two main techniques have been used to identify the perception of thirst and its alleviation by drinking. The first method is to monitor the volume of drink voluntarily ingested by an individual within an allotted time period and to compare the amount drunk with the volume of fluid required to restore a given water deficit or other imbalance of the body water pools. The other method is to assess the individual's perceived rating of thirst by asking him or her to record on a visual...

Management

The decision about the treatment of gall stones will depend strongly on the presentation of the patient. Asymptomatic gall stones should not be treated surgically. This recommendation is based on multiple studies, including several prospective studies, that showed that patients with asymptomatic gall stones, observed over many years, develop symptoms or biliary complications only on rare occasions. In one study of 123 people with asymptomatic gall stones followed for 11-24 years, biliary pain...

Macronutrients and Physical Activity 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 does show 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...

Body Water and Electrolytes

Man is dependent on ready access to water for survival. Water is the largest component of the human body and the total body water content varies from approximately 45 to 70 of the total body mass this therefore corresponds to about 33-531 for a 75 kg man. The water content of the various tissues is maintained relatively constant as adipose tissue has a low water content (Table 1) Table 1 Water content of various body tissues for an average 75 kg man Table 1 Water content of various body tissues...

Adaptation to Low Protein Intakes Nitrogen Balance

Nitrogen equilibrium is a state in which, for given intake of nitrogen, an equivalent amount of nitrogen is lost from the body via urine, feces, skin, sweat, etc. In general, when protein intake is low, dietary protein is used more efficiently, urea nitrogen excretion is reduced, and amino acid synthesis pathways are stimulated. The liver plays an important role in the adaptive process since it is the only organ that can transform the nitrogen from amino acids into urea. The metabolic activity...

Dietary Antioxidants and Human Health

Plants produce a very impressive array of antioxi-dant compounds, including carotenoids, flavonoids, cinnamic acids, benzoic acids, folic acid, ascorbic acid, tocopherols, and tocotrienols, and plant-based foods are our major source of dietary antioxidants. Antioxidant compounds are concentrated in the oxidation-prone sites of the plant, such as the oxygen-producing chloroplast and the PUFA-rich seeds and oils. Plants make antioxidants to protect their own structures from oxidant stress, and...

Malignant Complications of Celiac Disease

The complications of celiac disease can be divided into malignant and nonmalignant complications. In addition, the malignant complications of celiac disease are most commonly that of non-Hodgkin's lymphoma of a T cell variety. This particular tumor occurs in patients who have not been compliant with the diet or within 3 years of diagnosis. The risk of lymphoma or other malignancies appears to drop once a gluten-free diet has been instituted. While the relative risk of malignancy in celiac...

Clinical Findings of Frank Deficiency

The clinical findings of frank biotin deficiency in adults, older children, and infants are similar. Typically, the findings appear gradually after weeks to several years of egg-white feeding or parenteral nutrition. Thinning of hair and progression to loss of all hair, including eyebrows and lashes, has been reported. A scaly (seborrheic), red (eczematous) skin rash was present in the majority in several, the rash was distributed around the eyes, nose, mouth, and perineal orifices. These...

Clinical Types and Etiology of Diarrhea

Since nutritional costs of diarrhea vary by etiology and clinical type, a discussion of different types of diarrhea is pertinent. Diarrheal episodes can be classified based on clinical presentation as inflammatory (dysentery) and noninflammatory (nondysentery) diarrhea. Therefore, the clinical presentation of diar-rheal illnesses may suggest a causative diagnosis. Diar-rheal episodes can also be classified based on duration as acute (< 14 days) and persistent (> 14 days) diarrhea. The...

Classification and Chemical Structure

Carbohydrates are classified into four categories according to their chemical structure and degree of polymerization monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides are the simplest form of carbohydrate and cannot be further hydrolyzed into smaller subunits. According to their chain length, the monosaccharides can be divided into several categories, the more nutritionally important being the pentoses, with skeletons containing five carbon atoms (e.g.,...

Clinical Features

Gout is typically an episodic monoarthritis, although polyarticular gout (involving three or more joints) occurs in approximately 10 of cases. The description of the pain of acute gout by Thomas Sydenham in the seventeenth century remains among the best The victim goes to bed and sleeps in good health. About two o'clock in the morning he is awakened by a severe pain in the great toe more rarely in the heel, ankle, or instep. This pain is like that of a dislocation then follow chills and a...

The Metabolic Hypothesis

Given the fact that most people who lose weight are unable to sustain their losses, a metabolic hypothesis was formulated. It was proposed that if weight loss dieting caused permanent decreases in metabolic rate, the weight would be easily regained and every subsequent weight loss attempt would be more difficult. In the 1990s, the National Task Force on the Prevention and Treatment of Obesity in the United States reviewed the evidence and reported an overall lack of support for the hypothesis...

Nutritional Management of Tuberculosis Patients

The extent to which optimal nutrient intake improves the body's ability to heal during (and after) TB treatment is not well established. Fortunately, the immunological deficits associated with PEM and various micronutrient deficiencies are reversed rapidly with nutritional rehabilitation. One would expect this to improve recovery. The scientific literature is limited, however, with regard to the effect of nutrition on the outcomes of treatment. Only one randomized, double-blind trial is known,...

Amino Acids and Protein

Neurons and glial cells in brain use amino acids to produce proteins. In addition, certain amino acids are used to produce small functional molecules such as neurotransmitters. Does diet influence amino acid flow into brain, and their use in generating proteins and transmitters The path from diet to brain proceeds from amino acid absorption from the gastrointestinal tract, insertion into the circulation, and extraction by brain. This extraction process involves the BBB, which contains a number...

Recommended Potassium Intake Current Intake and Dietary Sources

On the basis of available data, an Institute of Medicine committee set an Adequate Intake for potassium at 4.7g day (120 mmol day) for adults. This level of dietary intake should maintain lower blood pressure levels, reduce the adverse effects of salt on blood pressure, reduce the risk of kidney stones, and possibly decrease bone loss. Current dietary intake of potassium is considerably lower than this level. Humans evolved on a diet that was rich in potassium and bicarbonate precursors and low...

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...

Immune Modulators

Several substances produced by animals and fungi have been investigated for immune-modulating effects. Fish oils are the most studied. As a source of n-3 fatty acids, fish oil consumption by humans has been shown to influence the synthesis of inflammatory signaling molecules like prostaglan-dins, leukotrienes, and cytokines. In addition to direct effects on prostanoid synthesis, n-3 fats have also been shown to directly alter the intracel-lular availability of free calcium ions, the function of...

Food Allergy

Food allergy is an adverse reaction to food in which the reaction is immune mediated. The immunological response comprises food-specific antibodies (IgE mediated), immune complex production, and muco-sal T cell-mediated reactions. Food allergy can be serious and lead to anaphylactic shock. This must be distinguished from food intolerance, which is a reproducible adverse reaction to a specific food or food ingredient, either as a result of abnormal absorption of a sugar due to an enzyme...

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...

Potential Importance of Phytoestrogens to Human Health Molecular Mechanisms of Action

The probable beneficial effects of phytoestrogens against breast cancer are likely to be mediated via numerous mechanisms. However, it has not been fully established whether the protective effects of soya and cereals result from their phytoestrogen content or from some other effect. Many studies utilising breast cells in culture such as the oestrogen-sensitive MCF-7 cell line show that phytoestrogens (genistein was used in most of studies) stimulate tumor growth at low concentrations while...

Regulation of Functional Foods in the United States

Current US food regulations do not specifically address functional foods but, rather, include them in several categories within conventional foods, food additives, dietary supplements, medical foods, or foods for special dietary use. All of these fall under the amended Federal Food, Drug and Cosmetic Act (FDCA) of 1938 and are implemented under regulations from the Food and Drug Administration (FDA). Four types of claims can be used to communicate the usefulness of functional foods to consumers...

Exercise and Energy Balance

Energy balance occurs when the total energy expenditure of an individual equals his or her total energy intake from the diet. If intake exceeds expenditure the result is an increase in the storage of energy primarily as body fat. If intake is below expenditure, body energy content or body fat decreases. In humans, energy is expended in three ways maintaining the physiological functions of the body at rest, often termed resting metabolic rate (RMR) ingesting food and digesting and assimilating...

Factors Affecting Metabolic Rate

The process of oxidation involves a series of enzyma-tically controlled biochemical reactions leading eventually to the combination of oxygen with the carbon and hydrogen components of the body's fuels to yield the carbon dioxide and metabolically derived water. The incompletely oxidized nitrogen is excreted as urea, which is synthesized by the liver and excreted by the kidneys. The intermediate steps in the metabolism of the body's fuels are linked biochemically to drive the generation of...

Evolutionary Aspects of Diet Relative to n3 Fatty Acids and the n6n3 Balance

On the basis of estimates from studies in Paleolithic nutrition and modern-day hunter-gatherer populations, it appears that human beings evolved consuming a diet that was much lower in saturated fatty acids than today's diet. Furthermore, the diet contained small and roughly equal amounts of n-6 and n-3 PUFAs (ratio of 1-2 1) and much lower amounts of trans-fatty acids than today's diet (Figure 3). The current Western diet is very high in n-6 fatty acids (the ratio of n-6 to n-3 fatty acids...

Why is Weight Loss Maintenance Difficult

Long-term weight loss maintenance may be difficult due to a combination of physiological, environmental, and psychological factors. Proposed physiological factors contributing to weight regain include reduced resting metabolic rate and insulin and leptin resistance. However, investigations examining metabolic factors in individuals who have lost weight have not been able to consistently document changes in physiological characteristics that would explain the tendency for weight regain to occur....

Hepatobiliary Disorders

Biliary atresia This disorder is the prototypic biliary tract disorder in infancy, accounting for 50 of all liver transplants in the pediatric age group and 10 of all liver transplants. It presents with cholestasis in early infancy there is a palliative surgical procedure called the Kasai hepatic portoenterostomy that, if performed before 60 days of age, may at least delay disease progression. In 20-25 of infants in whom the procedure is done in a timely fashion, liver transplantation may never...

World Health Organization

IJ Akre, World Health Organization, Geneva, Switzerland 2005 Elsevier Ltd. All rights reserved. The World Health Organization (WHO) is the intergovernmental organization within the United Nations (UN) system that acts as the directing and coordinating authority on international health work. It performs its functions through three principal bodies the World Health Assembly, the Executive Board, and the Secretariat. The objective of WHO, which has 191 member states, is the attainment by all...

Zinc

Zinc is perhaps the most ubiquitous and versatile of all metal cofactors. More than 300 enzymes have a zinc cofactor. Table 4 lists some of the important zinc enzymes. Zinc-binding proteins that engage DNA, the so-called zinc finger proteins, attest to the versatility of zinc in biological systems. Approximately 3 of the genome of mammals codes for zinc finger protein. As a cofactor, zinc can perform both structural and catalytic functions. In carbonic anhydrase, for example, zinc enters into a...

The Role of the Liver in Glucose Homeostasis

The liver, under the influence of insulin reaching it in high concentration in the portal vein after ingestion of a meal, switches from being a net exporter to net importer of glucose from the glucose pool. Any insulin not extracted and degraded by the liver passes through the heart and lungs to reach peripheral tissues, notably muscle, adipose tissue, and skin, where, providing the concentration of insulin in blood is sufficiently high, it promotes glucose uptake. Figure 1 Schematic...

Classification and Nomenclature of Glycerophospholipids

Glycerophospholipid classes are commonly referred to as phosphatidylcholine, phosphatidylethanola-mine, etc. They are composed of a spectrum of molecular species (phospholipid molecular species are the individual different molecules within any different class of phospholipid determined by the combination of fatty acids esterified to the glycerol backbone. Any given mammalian cell contains up to 1000 individual phospholipid molecular species) defined by the substituent fatty acid groups attached...

Absorption Transport and Storage Cholesterol Absorption

Cholesterol in the intestinal lumen typically consists of one-third dietary cholesterol and two-thirds biliary cholesterol. The average daily diet contains 300-500 mg of cholesterol obtained from animal Cholecalciferol see Vitamin D Physiology, Dietary Sources and Requirements Rickets and Osteomalacia Table 1 Average cholesterol metabolism values for a 70-kg adult Cholesterol pools and flux Mass Table 1 Average cholesterol metabolism values for a 70-kg adult Cholesterol pools and flux Mass Bile...

Epidemiology

IBD presents in a bimodal manner as pertains to age, first in late adolescence or early adulthood and a smaller peak in the fifth decade of life. The sexes are equally affected by ulcerative colitis in adults, the incidence of Crohn's disease is 20-30 higher in women. In terms of trends in disease over time, the incidence of ulcerative colitis remained stable during the second half of the twentieth century Crohn's disease has demonstrated a marked increase across all age groups since 1950....

Cataracts and Photoreceptors

Several micronutrients, especially those that can have antioxidant functions in living tissues, have recently been investigated in relation to possible protection against degenerative eye diseases, such as cataract. Studies in animal models have suggested, albeit indirectly, that riboflavin status may be important here, and several recent epidemiologi-cal studies, including an intervention study in one region of China, have supported the suggestion that good riboflavin status, or riboflavin...

Physiological Regulation of Thirst

Because thirst is the major factor controlling water intake, the physiological regulation of thirst is associated with the need to maintain a relatively stable volume of TBW. Although water is lost from the body continually, albeit usually in relatively small amounts, and hence the body is almost always developing a water deficit, water intake is intermittent. The amount of fluid usually ingested is in excess of that required to replace the losses incurred since the last water intake. The...

Nutritional Value of Fish and Shellfish Introductory Remarks

Fish and shellfish are excellent sources of protein. A 100 g cooked serving of most types of fish and shellfish provides about 18-20 g of protein, or about a third of the average daily recommended protein intake. The fish protein is of high quality, containing an abundance of essential amino-acids, and is very digestible by people of all ages. Seafood is also loaded with minerals such as iron, zinc, and calcium. The caloric value of fish is related to the fat content and varies with species,...

Dietary Lipid Approaches to the Prevention and Management of CVD

Dietary fat serves as a major energy source for humans. One gram of fat contributes 9 cal, a little more than twice that contributed by protein or carbohydrate (4calg 1) and somewhat more than that contributed by alcohol (7calg 1). When considering the importance of the level of dietary fat with respect to CVD prevention and management there are two major factors to consider the impact on plasma lipoprotein profiles and body weight. The potential relationship with body weight is important...

Introduction

Historically, the measurement of the body and its components centered around cadaver analyses where specific tissues and organs were extracted from the body for inspection. The extraction of tissue samples from the living body was a step forward in allowing for the analyses of tissue morphology in a state more closely resembling the in vivo state. However, both cadaver and in vitro tissue analyses are subject to inaccuracies when extrapolations are being made to the living body. Nevertheless,...

Superior Mesenteric Artery Syndrome

Superior mesenteric artery (SMA) syndrome is a condition in which the third portion of the duodenum is intermittently compressed by the overlying SMA, resulting in gastrointestinal obstruction. Symptoms include recurrent vomiting, abdominal distension, weight loss, and postprandial distress. People with CP are at high risk for several of the reported causes of SMA syndrome, including body cast compression, severe weight loss, prolonged supine positioning, and scoliosis surgery. Consequently, it...

Metabolic Response

Increased glucose demand is initially met by gly-cogenolysis. When glycogen stores are exhausted, lipolysis and protein catabolism increase to supply gluconeogenic substrates. This hypermetabolic response is accompanied by increased cardiac output, increased oxygen consumption, and increased thermogenesis. The physical loss of skin cover has other major effects, including fluid loss, increased heat loss by evaporation, and loss of local immune function. Skin grafting will provide some cover for...

Chemical and Physical Properties of Lycopene its Food Sources and Enteral Absorption

Lycopene is the most commonly encountered of that subgroup of the naturally occurring carotenoids that have a straight-chain poly-isoprenoid molecule without any terminal ,3-ionone ring structures (Figure 1). The chain length and number of conjugated double bonds determine the absorption spectrum, which peaks at 472 nm with a molar extinction coefficient, e1 o of 3450. It is one of the most nonpolar members of the carotenoids, and in organic solution it is also one of the most easily oxidized...

Nutritional Modification

It is clear that diet contributes in substantial ways to the development of age-related diseases and that modification of the diet can contribute to their prevention and thus help to improve the quality of life in old age. Macronutrient intake levels can play a significant part in the progression of age-related diseases and affect the quality of life. For example, the total and proportional intakes of polyunsatu-rated fatty acids and saturated fatty acids in the Western diet may have an effect...

Analytical Studies

Cohort studies Cohort studies involve the collection of information from healthy participants who are followed over time and observed for the occurrence of new cases of disease (incident cases). During or at the end of follow-up, the disease frequency within a cohort may be measured as either a cumulative incidence rate (the number of cases divided by the entire base population) or an incidence density rate (the number of cases divided by the total follow-up time accumulated by all members of...

Further Reading

Abdullah M and Wheeler EF (1985) Seasonal Variations and the intra-household distribution of food in a Bangladeshi village. American Journal of Clinical Nutrition 41 1305-1313. Annegers JF (1973) Seasonal food shortages in West Africa. Ecology of Food and Nutrition 2 251-257. Branca F, Pastore G, Demissie T, and Ferro-Luzzi A (1993) The nutritional impact of seasonality in children and adults of rural Ethiopia. European Journal of Clinical Nutrition 47 840-850. Chambers R (1982) Health,...

Definition Classification and Prevalence

Premenstrual syndrome, or premenstrual dysphoric disorder (PMDD), is an association of distressing physical, psychological, and or behavioral symptoms which occur in the luteal phase (second half) of the menstrual cycle of sufficient severity to interfere with the normal activities and personal relationships of many women. Although the late luteal phase is the most common time for symptoms of PMS to be experienced, occasionally symptoms may occur as early as ovulation. To be classified as PMS,...

Biochemistry and Metabolic Functions

Fermentation

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...

The Function and Nature of Religious Food Practices

What people need to eat to survive as biological organisms and what they choose to eat as human beings are two different matters. While practically any food combination which supplies the requisite nutrients to meet physiological needs is adequate for biological purposes, this is clearly not the case for cultural purposes. People make choices from the foodstuffs available to them which reflect a constellation of social, economic, political, and cultural influences, as well as personal...

Selenium Deficiency Viral Disease and Mutation and Immune Function

Initially, Keshan disease was thought to be a deficiency disease alone, involving inadequate intakes of Se and also of Mo, Mg, and thiamin. However, seasonal variations in symptoms suggested that at least one other interacting factor was likely involved. Later, an enterovirus and a Coxsackie virus (strain B4) were isolated from affected individuals. The same Coxsackie virus was able to produce severe heart pathology in mice when they were fed Se-deficient grain from Keshan endemic areas....

Nutrient and Drug Interactions

In Europe, 83 of 'apparently healthy' people in the previously mentioned SENECA study use an average of two types of drugs, with antihypertensives (33 ), analgesics (31 ), diuretics (24 ), sleeping pills (18 ), and psychotropic drugs (17 ) taken most often. Many drugs taken by the elderly can interfere with nutritional status. The possible effects include suppression or stimulation of appetite and impaired nutrient absorption and metabolism. For example,...

Carbohydrates and Energy Metabolism Glucose

The breakdown of glucose can be divided into two major parts the anaerobic conversion of glucose to pyruvate, known as glycolysis, and the aerobic breakdown of pyruvate to carbon dioxide and water, which involves the tricarboxylic acid cycle and the electron transport chain. Glycolysis is the series of enzymatic steps leading to the breakdown of one molecule of glucose to produce two molecules of pyruvate (Figure 1). Gly-colysis occurs in the cytosol of different cells, and all human cells are...

Type of Dietary Carbohydrate and the Glycemic Index

The glycemic index of a carbohydrate is influenced by its rate of intestinal absorption, which in turn is influenced by its composition, tertiary structure, type of starch, and susceptibility to enzymic digestion. Complex carbohydrates are polymeric chains of repeating monosaccharide units. Starches comprise repeating glucose units. The glycemic indexes of different starches are determined by their susceptibility to enzymic digestion, not chain length. White bread and pasta have similar chain...

Issues Associated with Measurement of Dietary Intake

There is potential for the occurrence of measurement error with the measurement of any exposure such as when using dietary methods to measure nutritional intake. Errors may arise as a result of flaws in the design of the measurement instrument or during data collection or processing. Measurement error may also occur as a result of individual characteristics of participants in studies. Measurement error can be defined as the difference between the measured exposure (or measure of dietary intake)...

Genetics Affects Nutrient Requirements

There are many examples of nutrient requirements being influenced by genetic background. For example, in the early years of determining the human need for vitamin C, human studies showed that there could be large individual differences in the need for this essential vitamin. In addition to genetic variability, vitamin C need was increased in smokers versus nonsmokers and in people with diabetes compared to people without this disease. Similar observations have been reported for vitamin A. A...

Changes in Calcium Metabolism during the Life Span

The total body calcium content of the newborn infant is approximately 0.75 mol (30 g), which increases during growth to approximately 1000 g in adult women and 1200 g in adult men. This represents an average daily accumulation of approximately 2.5-3.7mmol (100-150mg) from infancy to adulthood. The efficiency of calcium absorption is highest during infancy (approximately 60 ), and the amount absorbed from breast milk does not appear to be affected by calcium consumed in solid foods. During the...

National Trends in Caries Prevalence

Data on the prevalence of dental caries within populations are nowadays very reliable as they are collected to internationally recognized standards. Surveys of 12-year-old children are carried out in most countries, and the data are collated by the World Health Organization (see Table 1). In contrast, data for adults are scarcer. The general picture emerging from the repetition of these national surveys is clear. In many countries the prevalence of caries is falling, often dramatically. In...

Pathophysiology of Uncontrolled Diabetes

Uncontrolled diabetes mellitus occurs when circulating insulin levels are inadequate to lower elevated blood glucose concentrations. This condition includes a spectrum of metabolic abnormalities that range from the effects of mild insulin deficiency (i.e., hyperglycemia) to the effects of marked and prolonged insulinopenia (i.e., ketoacidosis and fluid and electrolyte depletion). Diabetic ketoacidosis, which is the most severe acute manifestation of insulin deficiency, is almost entirely...

Gout

Gout is a painful, acute form of arthritis caused by the accumulation of crystals of uric acid in the joints (typically the great toe is the first site to be affected). The pain may be relieved by antiinflammatory drugs or by colchicine, and the accumulation of urate is halted by the drug allopurinol, which inhibits xanthine dehydrogenase. Nevertheless, adopting a low-purine diet has an important role in alleviating the effects of gout. Historically, 'primary' gout affecting predominantly...

Intestinal Absorption and Transport into Somatic Cells

At physiologic pH, the carboxylate group of biotin is negatively charged. Thus, biotin is at least modestly water-soluble and requires a transporter to cross cell membranes such as enterocytes for intestinal absorption, somatic cells for utilization, and renal tubule cells for reclamation from the glomeru-lar filtrate. In intact intestinal preparations such as loops and everted gut sacks, biotin transport exhibits two components. One component is saturable at a km of approximately 10 mM biotin...

The National Weight Control Registry

The largest observational study of successful weight losers is the NWCR in the United States. The NWCR is a registry of individuals who have lost at least 13.6 kg and kept it off at least 1year. On average, these participants have lost more than 27.3 kg and kept it off more than 6 years. Information that registry members have provided has aided in learning about the weight loss maintenance process. Registry participants are recruited through newspaper and magazine articles and thus are a...