Complementary Feeding Period 624 Months

Undernutrition, especially wasting and micronutri-ent deficiencies, is most prevalent during the complementary feeding period. Linear growth retardation is usually well established during this stage of the life cycle. This age group is particularly vulnerable because of its high nutrient requirements that cannot be supplied through breast milk alone. A variety of nutrition interventions have been proposed to prevent undernutrition, and the use of multiple approaches is likely to be most...

Insulin Resistance and Hyperinsulinemia

'Insulin resistance' refers to the phenomenon of insensitivity of the cells of the body to insulin's actions. Different tissues may have different insulin sensitivities. For example, adipose tissue may be more sensitive to insulin than muscle tissue, thus favoring the deposition of fatty acids in adipose tissue and diminished fatty acid oxidation in muscle. Insulin resistance is usually associated with hyper-insulinemia. Hyperinsulinemia is an independent marker that predicts the development of...

Hunger Physiological Determinants

Stomach distension and the detection of macro-nutrients such as fat or protein within the gut are all powerful satiety cues. They bring a meal to an end and for a time inhibit further consumption. Eventually, hunger again prevails and food intake follows. The flux between hunger and satiety is episodic and underpins the expression of our eating behavior throughout the day. However, it is not just the absence of episodic satiety cues (e.g., stomach distension and intestinal or absorbed...

Definitional Considerations

In its broadest context, malnutrition is a state of having an inappropriate nutritional status with respect to one or more macronutrient (water, electrolyte, protein, or fat) or micronutrient (vitamin or mineral) constituent of the body. This imbalance can be a deficit, leading to an insufficient supply or content of the nutrient (undernutrition), or an excess, leading to an excessive content or overloading of the organism with a nutrient (overnutrition). Victor Herbert enumerated six possible...

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...

Fia

Heterozygotes (carriers - clinically normal) Figure 1 Mode of inheritance of CF a Mendelian inherited recessive characteristic. The median age of survival has dramatically risen from approximately 2 years in the 1940s to around 30 years in the 1990s. A current survival estimation following diagnosis is approximately 40 years. This improved prognosis can be attributed to a combination of factors including aggressive management of infections, effective antibiotics, improved nutritional...

Emerging Issues in the Twenty First Century

Some of the main emerging and reemerging nutrition issues of the new millennium for developing countries are those that reflect changing economic, demographic, and disease patterns and include HIV AIDS, the nutrition transition, refugees, adolescents, and aging. In developed countries, aging is also one of the main emerging issues, along with the continued increase in obesity in both adults and children, with concomitant increases in related diseases such as diabetes. It has been recognised...

Manifestations of Lead Toxicity

Perhaps due to their increased absorption of lead from the diet, children appear to be more susceptible to the toxic effects of lead. These involve the nervous system, including cognitive dysfunction the liver the composition of circulating blood kidney function the vitamin D endocrine system and bone (Table 1) and gene function, possibly with resultant teratogenic effects. Chronic exposure results in high blood pressure, stroke, and end-stage kidney disease in adults. Neurologic Full-blown...

Definition

It is now accepted that some people exhibit, in the course of their everyday life, symptoms similar to those caused by acute neuroglycopenia and may, if accompanied by a capillary or arterialized venous blood glucose concentration of 2.8-2.5 mmoll-1 or less, justify description as being of postprandial reactive hypoglycemic origin. Reactive hypoglyce-mia may itself be a consequence of any one of a large number of well-recognized but generally uncommon conditions that can also produce...

Micronutrient Deficiency

In older people at risk of nutritional compromise, micronutrient supplementation deserves special attention, in order to forestall the development of micro-nutrient deficiency (Table 6). The clinical features of established vitamin deficiency are well recognized. The first recourse in the management of micro-nutrient deficiencies should be the provision of a well-balanced diet. In the presence of a functioning gastrointestinal tract, an adequate diet containing the recommended daily allowance...

Cofactor Deficiencies

Biotin is an essential cofactor for the four carboxylase enzymes propionyl CoA carboxylase, methylcrotonyl CoA carboxylase, pyruvate CoA car-boxylase, and acetyl CoA carboxylase. It is endo-genously derived from lysine and also present in its protein-bound form in small amounts in many foods. Holocarboxylase synthetase (HCS), which forms the inactive parent apoenzyme, is also biotin dependent. Enzyme activation requires free biotin, which is released by the action of biotinidase this enzyme...

Distribution and Impact on Health

In general, carotenoid concentrations in serum reflect concentrations contained in the food that is ingested. Carotenoids have been found in various human organs and tissues. These include human liver, lung, breast, cervix, skin, and adipose and ocular tissues. The major storage organs are adipose tissue (probably because of its volume) and the liver. Tissues containing large amounts of LDL receptors seem to accumulate high levels of carotenoids, probably as a result of nonspecific uptake by...

Diarrhea Malnutrition Interaction

Diarrheal illnesses are more common, last longer, are clinically more severe, and are more likely to have a fatal outcome for impoverished children in less developed countries because of a complex interaction between infection, protein-energy malnutrition, and micronutrient deficiencies. Diarrhea and malnutrition have a bidirectional relationship in which malnutrition increases the incidence and duration of diarrhea and, conversely, diarrhea exerts a negative effect on nutritional status....

History of Food Folklore

In addition to sustaining life, food has come to play a symbolic role in both religious ceremonies and cultural traditions. For example, rice has been associated with fertility in many cultures for millennia and continues to be thrown on newly married couples today. Similarly, bread has been regarded as a symbol of divinity and has played an important role in religious services and observances. Curative properties have also been ascribed to many foods for thousands of years. In ancient Rome,...

Cofactors in Biochemical Pathways

Table 1 lists vitamins and nonvitamins that are known to give rise to many of the organic cofactors in humans. Figure 1 provides a glimpse into their importance by showing the location of organic cofactors in the biochemical pathway for oxidizing glucose and other biocompounds to CO2 and H2O. That overall reaction for glucose is C6Hx2O6(glucose) + 6O2 6CO2 + 6H2O One sees that at least seven distinct B vitamin-derived coenzymes are needed to complete the transition. Nicotine adenine...

Polyps

Intestinal polyps are intraluminal protuberant tumors characterized by their gross morphological appearance, location(s), number, size, and presence (pedunculated) or absence (sessile) of a stalk. Additional salient features include specific histological features used to discriminate between types and to aid in predicting malignant potential. Extraintestinal manifestations are also associated with specific poly-posis syndromes. Age of occurrence is important with respect to clinical...

Famines in History

Famine has afflicted humankind, shaping its demography and history from antiquity. Records of famine in ancient Egypt during the third millennium BC are depicted in bas-relief on the Causeway of the Pyramid of Unas in Saqqura. Biblical accounts of a famine resulting from drought in Egypt during the second millennium BC (Middle Kingdom) that stretched to Mesopotamia describe the devastation wrought on the land and society and the means by which Joseph predicted and managed its consequences. The...

Vegetarian Eating Patterns

The term vegetarian diet does not fully describe the variety in nutrient intakes and health status of those Table 1 Common types of vegetarian dietary patterns categorized by animal food use Limit or avoid red meat and other flesh foods may also restrict poultry, fish, and seafood. Diets are similar in most respects to nonvegetarian diets Avoidances include all meat, poultry, and often fish, but consume milk products and eggs. Iron may be limiting and it can be obtained from iron-fortified...

Absorption of Fructose

Dietary fructose is ingested as the simple monosac-charide and also as part of the disaccharide sucrose. Sucrose is hydrolyzed by sucrase at the intestinal brush border to yield one molecule of glucose and one of fructose. Glucose is rapidly absorbed via a sodium-coupled cotransporter and arrives at the liver via the portal circulation. Fructose absorption is accomplished primarily by a fructose-specific hex-ose transporter, GLUT-5. This transporter is found in the jejunum on both the brush...

Cardiovascular Disease Population Studies

The incidence of cardiovascular disease within populations with either very high or very low intakes of n-6 fatty acids may provide some indication for optimal intakes of n-6 fatty acids. Within populations with low n-6 fatty acid intakes (< 3 ) there would appear to be a benefit of having a higher n-6 fatty acid intake on cardiovascular disease risk reduction. These observations suggest that very low n-6 fatty acid intakes increase the risk for cardiovascular disease. The presence of EFA...

Complications of PN

Short-term complications of PN therapy may be divided into three classes mechanical, infectious, and metabolic. Longer term complications can include overfeeding, hepatobiliary complications, and metabolic bone disease. Central catheter placement can be associated with serious mechanical complications, including pneumothorax, arrhythmias, catheter-related thrombosis, and catheter occlusion. Radiologic confirmation of line placement is necessary before initiating PN therapy. Catheter occlusion...

Info

Some children have no recognizable pathological abnormalities and yet they fail to thrive. In some children inappropriate management of the feeding problems described earlier underlies poor growth. Others may be underfed because of poverty, ignorance, or incompetence amongst carers. Some parents, anxious to forestall obesity or cancer and cardiovascular conditions in later life, feed diets that are too restricted in nutrient quantity or variety for normal growth, or which follow rigidly the...

Disorders of Fatty Acid Oxidation

Disorders of fatty-acid oxidation have been recognized only since the early 1980s, but as a group they represent the most common inborn errors of metabolism. Fat provides a significant source of energy in the form of glucose and ketone bodies during times of metabolic stress (such as febrile illness) or during prolonged fasting. Free fatty acids, released from the adipose tissue, are transported into the mitochondria via the carnitine shuttle system, where they undergo fi-oxidation (Figure 4),...

Health Effects of Carbohydrates

Carbohydrates are stored in the human body as glycogen mainly in the liver and muscle. The human body has a limited storage capacity for carbohydrates compared to fat. The total amount of carbohydrates stored in tissues and circulating in the blood as glucose is approximately 7.56 MJ (1800 kcal). Diets high in carbohydrate ensure adequate glycogen storage available for immediate energy utilization. Carbohydrates are the preferred energy source for the human brain and have an important role in...

Siadh

Production Decreased rate of absorption Flushing, headache, nausea, vomiting, tachycardia proxetil Cefuroxim axetil Cefixime Cefachlor Cephalexin Histamine 2 antagonist Antibiotic (quinolone) Tyramine-rich foods (avacado, canned figs, aged cheese, cola beverage, coffee, chocolate, wine, soy sauce, fermented meats, yeast, yoghurts) No effect (may take with food) Bioavailability increased with food Bioavailability increased with food Decreased rate of absorption Decreased rate of absorption...

Metabolism and Turnover

The primary role of pantothenic acid is in acyl group activation for lipid metabolism, involving thiol acylation of CoA or of ACP, both of which contain 4-phosphopantotheine, the active group of which is -mercaptoethylamine. CoA is essential for oxidation of fatty acids, pyruvate and a-oxogutarate, for metabolism of sterols, and for acetylation of other molecules, so as to modulate their transport characteristics or functions. Acyl carrier protein, which is synthesized from apo-ACP and coenzyme...

The Cycle of Malnutrition and Infection

Malnutrition and infection interact in a cycle of adverse events (Figure 1) whereby malnutrition impairs immunocompetence by affecting both nonimmunological defense mechanisms (such as epithelial membrane integrity) and immunological defenses (e.g., cytokine activity, neutrophil function, T-cell maturation) thereby increasing host Figure 1 The cycle of malnutrition and infection. (Reproduced from Tomkins A and Watson F (1989) Malnutrition and Infection A Review. Nutrition Policy Discussion...

Oral Glucose Tolerance Test

In the absence of an obvious elevation in fasting or random plasma glucose levels, the diagnosis of diabetes mellitus can be made with an oral glucose tolerance test (OGTT). This involves, for the non-pregnant adult, the ingestion of a solution containing 75 g of glucose over 5 min, with a measurement of baseline and 2-h plasma glucose. The criteria used to diagnose diabetes are listed in Table 1. The diagnosis can be made if the fasting glucose exceeds 7.0mmol l or the 2-h value exceeds...

Diabetes in Pregnancy

For women with diabetes, nutritional counseling should include adequate dietary intake, frequent glucose monitoring, insulin management to meet the growth needs of the fetus, maintaining optimal blood glucose levels, and preventing ketosis and depletion of the mother's nutrient stores. The demands of pregnancy may impose a need for insulin in pregnant women whose condition was controlled through diet alone in the nonpregnant state. Because of hormonal changes during the first and second half of...

Mucus Mucin Glycoproteins

Mucus is continuously produced by goblet cells to lubricate and protect the GI epithelium. The primary gene identified that is located in the goblet cell and predominantly responsible for the production and secretion of mucus and its resulting sugar, mucin, is the MUC2 gene. This is through an elaborate process of encoding a peptide modified by o-glyco-sidic bonds to a variety of carbohydrate residues to amino acids serine or threonine resulting in a glyco-protein with high carbohydrate content...

What Is a Dietary Supplement How Are They Regulated in Different Countries

Each country has developed regulatory definitions and systems that place dietary supplements, particularly botanicals, into categories of drugs, traditional medicines, or foods. However, in the late 1980s, many countries launched major changes in regulations that may or may not have been approved at the time of this writing. Many regulations are still in draft form. The US Congress defined the term 'dietary supplement' in the Dietary Supplement Health and Education Act (DSHEA) of 1994. A...

Aflatoxin and Human Cancer

HCC is the fifth leading cause of cancer mortality throughout the world, and in areas of Asia and Africa it accounts for nearly 70 of all cancer deaths. Furthermore, due to the lack of symptoms in the early stages and rapid growth rates of tumors, most HCCs are discovered in very advanced stages. The 5-year mortality rate for individuals diagnosed with HCC is greater than 95 . In the People's Republic of China, HCC is the third leading cause of cancer mortality and accounts for at least 250,000...

Bone mineral density

Osteopenia is prevalent in diet-treated persons with PKU from early life. Reduced bone mineral density and or bone mass has been detected in up to approximately 50 of patients screened by various methods. These methods have included DEXA (dual energy X-ray absorptiometry), pQCT (peripheral quantitative computed tomography), and SPA (single photon absorptiometry). The defect seems to be characterized by a reduction in the speed of bone mineralization, especially after 8 years of age....

Structural Shifts in Income Diet Relationships Are Occurring

Changes in dietary behavior can be caused either by shifts in the composition of society regarding the plurality of the educated, rich, or urban residents or by changes in actual behavior of those with specific characteristics. This latter type can include a change in consumption behavior such that for the same level of education or income, a person would buy different amounts or types of commodities at different points in time. Research conducted in China shows that there have been profound...

Sensory Stimulation and Palatability

Palatability can be measured as the subjective preference for a food, its subjective pleasantness, or indeed the amount (in grams) of a food a subject eats. The relative palatability of a food can be determined by choice tests or taste tests relative to other standard ingestants (e.g., the 5 sugar solution). However, there has been much more controversy over the actual definition of palatability. In general the palatability of a food can be thought of as (1) the momentary subjective orosensory...

Tests for Circulating IgE Antibodies the Radioallergosorbent RAST Test

The radioallergosorbent (RAST) test is the best known of a number of laboratory procedures for the detection and measurement of circulating IgE antibody. Unfortunately, the clinical interpretation of RAST test results is subject to most of the same pitfalls as that for skin prick testing. Additional problems with RAST tests are the cost, and the fact that a very high level of total circulating IgE (e.g., in children with severe atopic eczema) may cause a false-positive result. Depending upon...

Carbohydrate

Carbohydrate ingestion causes blood glucose to increase. In people without diabetes, the normal increase in blood glucose is approximately 0.5-2.8 mmol l (10-50 mg dl) above baseline, returning to baseline within 1-3 h. The pancreatic hormonal response to dietary carbohydrate mediates the return to normal. Insulin is the central mediator of energy metabolism. The basics of insulin-dependent energy metabolism in the fed and the fasting states are depicted in Figure 2. Although carbohydrate...

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...

Risk Factors

Squamous cell carcinoma Factors that cause chronic irritation and esophageal mucosa inflammation may increase the risk for esophageal squamous cell carcinoma. These factors include moderate to heavy alcohol drinking, smoking, achalasia, diverti-culi, and consumption of extremely hot beverages, coarse grains or seeds, lye, and caustic spices. The importance of alcohol consumption in the carcinogenesis of esophageal squamous cell carcinoma is well recognized. However, the mechanisms by which...

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)...

Further Reading

Azzi A and Stocker A (2002) Vitamin E Non-antioxidant roles. Progress in Lipid Research 39 231-255. Brigeluis-Flohe R, Kelly FJ, Salonen JT ei a . (2002) The European perspective on vitamin E Current knowledge and future research. American Journa of C i'ni'ca Nutrition 76 703-716. Esposito E, Rotilio D, Di Matteo V ei a . (2002) A review of specific dietary antioxidants and the effects on biochemical mechanisms related to neurodegenerative processes. Neurobiology of Ageing 23 719-735. Frei B...

Absorption Transport and Storage

Absorption of manganese is thought to occur throughout the small intestine. Manganese absorption is not thought to be under homeostatic control. For adult humans, manganese absorption has been reported to range from 2 to 15 when 54Mn-labeled test meals are used and to be 25 when balance studies are conducted given the technical problems associated with balance studies, the 54Mn data are probably more reflective of true absorption values. Data from balance studies indicate that manganese...

Nucleic Acid Content of Foods

The nucleic acid content of different foods is expressed generally in terms of purine equivalents, with the data derived from the hydrolysis of nucleic acids and free nucleotides to the constituent bases. Careful analysis by Robert McCance, Elsie Widdow-son, and colleagues since the 1930s forms the basis of tables of the composition of foodstuffs. Foods may be classified into three groups high, low, or essentially purine free (Table 1). As a general rule, growing organisms such as yeast, or...

Established Recommended Intakes for Older Persons

In earlier versions of the RDAs for the US population (up to the 10th edition in 1989), the nutrient recommendations for all healthy adults over 51 years of age were combined as a single value. For the UN System, the age threshold in the early editions was 50 years or older. Concerted efforts to refine our understanding of nutrient requirements for older adults have been made over the past two decades. This allowed the US-Canada DRI process to establish categories for men and women aged 70...

Hemostatic Factors

W Gilmore, University of Ulster, Coleraine, UK 2005 Elsevier Ltd. All rights reserved. The two major processes that contribute to the pathogenesis of coronary heart disease (CHD) and stroke are atherosclerosis and thrombosis. These, in turn, involve inflammation and hemos-tasis two pathways that are linked both at the molecular and cellular levels. In addition to stimulating the inflammatory response, the proinflam-matory cytokines, chiefly interleukin-1beta (IL-1 3) and tumor necrosis factor...

The Postprandial Syndrome

Typically, the patient is a normal-weight woman of 20-50 years whose main complaint is of vague feelings of distress occurring predominantly mid morning, about 11.00 a.m.-12.00 noon, but occasionally mid afternoon or evening and never before breakfast. In between attacks, characterized by feeling of faintness, anxiety, nervousness, irritability, inner trembling, rapid heart beat, headache, and sweatiness, either alone or in combination, they may be completely well. More often they describe...

Mechanism of Hypoglycemia Glucose Pool in Fasting Subjects

Glucose is confined within the body to the extracellular fluid where it is referred to as the glucose pool detailed discussion of its regulation is outside the scope of this article except to stress that it reflects the concentration of glucose in the blood. This remains remarkably constant despite huge changes in the rates of delivery and utilization of glucose, by meals and exercise (and fasting), respectively, and is described as glucose homeostasis (Figure 1). The main but far from sole...

Neural Structures Critical to the Expression of Appetite

The CNS receives information generated by the sensory experience of eating, and from the periphery indicating the ingestion, absorption, metabolism, and storage of energy. To regulate appetite a variety of structures within the CNS integrate multiple signals, to assess the biological need for energy, to generate or inhibit conscious experiences of hunger, and subsequently to initiate the appropriate behavioral action. Information reaches the CNS via three main routes 1. Signals from the...

Probiotics and Prebiotics

Probiotics are live microbes that exert health benefits when ingested in sufficient quantities. Species of lactobacilli and bifidobacteria, sometimes combined with Streptococcus thermophilus, are the main bacteria used as probiotics in fermented dairy products. Most probiotic research has been done with nutra-ceutical preparations, but yogurt has been shown to alleviate lactose intolerance, prevent vaginal can-didosis in women with recurrent vaginitis, and reduce the incidence or severity of...

Metabolic Alkalosis

Metabolic alkalosis may be caused either by the excessive loss of acid or intake of alkali. The latter may be iatrogenic or factitious, with the excessive intake of prescribed antacids (such as sodium bicarbonate for heartburn or peptic ulcer disease) - the 'milk-alkali' syndrome. The loss of acid-rich gastric secretions in severe vomiting, for example, in cases of gastric outlet obstruction (due to pyloric stenosis, or a consequence of peptic ulcer disease), also leads to alkalosis....

Components of Metabolic Rate

Traditionally, the metabolic rate is divided into three components BMR, postprandial thermogenesis, and physical activity. The BMR usually comprises 50-60 of an individual's total energy expenditure and postprandial thermogenesis comprises 10 , which is used for the metabolic cost of processing (i.e., eating, absorbing, transporting, and storing food). The remaining energy is used for physical activity. The surge in oxygen uptake after a meal, known as postprandial thermogenesis, has been...

Measuring Nutrient Bioavailability in Humans

The first consideration is often whether it is necessary to have an accurate quantitative estimate of nutrient bioavailability, or whether an estimate of relative bioavailability compared to a known standard nutrient source will suffice. An accurate quantitative measure of bioavailability might be necessary when the intention is to provide data to derive a recommendation for dietary intake to meet a nutrient requirement. In this case, it is important to have a reasonably good estimate of the...

International Context International Promotion

Hunger and malnutrition were put on the international agenda by the League of Nations in the 1930s, and the first conference of the United Nations in 1943 was devoted to food and agriculture. It remained an important focus of the United Nations technical agencies, FAO, WHO, and UNICEF, which were created immediately after World War II. Other international organizations have since been established, including the World Food Programme, World Food Council, International Fund for Agriculture...

Exogenous Cholesterol Transport

Cholesterol is absorbed in the unesterified state, whereas the cholesterol secreted into the lymph is 70-80 esterified. This esterification process generates a concentration gradient of free cholesterol within the mucosal cell that may facilitate absorption rates. Cholesterol is esterified in intestinal mucosal cells by acyl-coenzyme A cholesterol acyl-transferase-2 to form cholesteryl esters, which are secreted from the basolateral surface of the entero-cyte as part of the chylomicrons. At...

Nsaid

Tyramine-rich foods (avocados, canned figs, aged cheese, cola beverages, coffee, chocolate, wines, soy sauce, fermented meats, yeast preparation, yoghurts) Alcohol Ascorbic acid Amino-acids Calcium phosphate Zinc Increased rate of absorption Hypokalemia Decreased rate of absorption no change in extent of absorption Hypocalcemia drug chelates divalent metal ions Hypomagnesemia Hypophosphatemia and Prolonged large doses result in increased risk for hypertensive crisis Rushing, headache, nausea,...

Glycogen Storage Disorders

Glycogen is a complex carbohydrate stored primarily in the liver and muscle. Liver glycogen provides glucose to maintain blood-sugar levels between normal feeding defects of the liver enzymes for glycogen Figure 6 Glycogen storage disease type I. degradation lead to hypoglycemia and or liver disease because of excessive accumulation of glycogen. Muscle glycogen is an important substrate for energy production for normal muscle function, so disorders are usually indicated by cramping with...

18o Weight Loss

The 18O isotope was (and still is) expensive and instrumental limitations meant that relatively large doses had to be given to achieve adequate measurement precision. However, in the 1980s human studies, which are the focus of this article, became possible and in 1998 a basic unified methodological approach was established as a result of a meeting of the experts in the field (International Dietary Energy Consultancy Group). The publication derived from this meeting remains a valuable tool. The...

Delays in Secretory Activation

A delay in the onset of milk secretion is a problem for the initiation of breast-feeding in a significant number of parturient women. A number of pathological conditions may delay secretory activation in women, including cesarean section, diabetes, obesity, and stress during parturition. The role of cesarean section is controversial, but if there is one it is likely to have only a modest effect. However, poorly controlled diabetes, stress from delivery, or obesity are associated with...

Large Scale Community Coronary Heart Disease and Diabetes Prevention Trials

Conducting large-scale, communitywide trials to address the prevention of obesity is a very expensive and difficult process consequently, evidence of this nature is very limited. However, a number of large CVD and diabetes prevention trials have included weight as an intermediary outcome, which can also provide useful information about effective strategies to address obesity, and have demonstrated that it may be possible to prevent weight gain if not reduce weight at a population level. The...

Nucleosides and Nucleotides in the Diet

In healthy adults, the normal diet is a good source of nucleic acids, nucleotides, and nucleosides, and no supplementation is necessary. Pharmacological uses for nucleosides and nucleotides Oral uridine, as described earlier, can be used where de novo biosynthesis of pyrimidines is defective, and it may be useful in reversing some effects of mitochondrial dysfunction and to minimize the toxic effect of the antitumor drug 5-fluorouracil. Uridine is also a precursor for UDP-glucose, essential for...

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...

Learned Appetites Satieties and Feeding Behavior

Animals and humans learn (or become conditioned) to associate a given food with the physiological consequences of having ingested it. They associate certain proximal stimuli such as the smell, color, taste, or texture of a food (the conditioning stimulus) with a set of sensations that are directly felt (sensory afferent inputs), in relation to the external stimulus and to the endogenous changes such as physiological and neuroendocrine responses to food. The physiological changes that occur as a...

Metabolism of Endogenous Nucleic Acids and Excretion of End Products

There is a considerable turnover of endogenous nucleic acids and ribonucleotides daily during muscle work, wound healing, erythrocyte senescence, mounting an immune response, etc. However, only a small fraction of these vital endogenous compounds are actually degraded and lost from the body. The contents of dead cells are normally used by nearby cells, and degraded RNA or cofactors are recycled within living cells using active 'salvage' routes. Salvage of the polynucleotides DNA and RNA begins...

Familial Hypoalphalipoproteinemia

Severe HDL deficiency, characterized by HDL cholesterol levels < 10mgdl-1 is rare and may be due to Tangier disease, apo A-I deficiencies, LCAT deficiency, or fish-eye disease. The apo A-1 deficiency states are due to rare deletions, rearrangements, or point mutations within the apo A-I C-III A-IV gene complex. Familial hypoalphalipoproteinemia is relatively common and is characterized by HDL cholesterol levels below the 10th percentile of normal. These subjects have been reported to have...

Regulation of Meal Size by Satiety Peptides and Adiposity Signals

Peptides in the gastrointestinal tract and brain are believed to play an important role in the body's decision to commence and conclude meal consumption. When a meal is being consumed, these peptides are secreted by the gut to indicate the level of satiety. Some of this information can be used by the brain to determine the feeling of fullness, in turn influencing the decision to cease consumption. Cholecystokinin (CCK), a polypeptide located in the peripheral and central nervous systems, is one...

Inborn Errors of Metabolism

Hypoglycemia is a manifestation of many inborn errors of metabolism (see Table 1) especially in children but also occasionally in adults. It is particularly important in some varieties of liver glycogen storage diseases, especially types I and III, and in disorders of fatty acid metabolism in which it is often the presenting symptom. Type I liver glycogen storage disease is due to a defect in glucose-6-phosphatase activity and produces a severe form of fasting hypoglycemia. Fortunately, this...

Traditional Low Purine Diet

The primary dietary modification that has traditionally been recommended to reduce uric acid production is a low-purine diet (< 75mg 24h Table 1). Uric acid is the end product of purine metabolism in humans, formed by oxidation of its precursors, the oxypurines, hypoxanthine and xanthine. With the advent of more powerful and effective urate-lowering drugs, however, dietary restriction of purine-rich foods is of decreasing importance. Although patients may be advised to avoid large quantities...

Physiological Activities of Prostaglandins and Leukotrienes

Bone remodeling, the continuous process of bone resorption by osteoclasts and bone formation by osteoblasts, is mediated by a number of factors, one of which is PGE2. However, the role of PGs in bone metabolism is somewhat contradictory, in that PGE2 can have both anabolic and catabolic effects. For example, PGs can stimulate the differentiation in vitro of precursors of both osteoclasts (responsible for bone resorption) and osteoblasts (bone growth). Both bone resorption and formation by PGE2...

Sequelae of Altered Metabolism in Visceral

Intraabdominal adipose tissue has metabolic characteristics that are different from those of adipose tissue from other sites. These differences seem to be most pronounced in the regions that are drained by the portal circulation. These 'portal adipose tissues' have a sensitive system for the mobilization of free fatty acids due to a preponderance of -adrenergic receptors and little a-adrenergic inhibition. The hypothesis has been advanced that the heightened responsiveness of intraabdominal fat...

Trace Elements Copper Selenium Chromium Fluoride Manganese and Molybdenum

Copper is required for the function of many enzymes, primarily oxidases. In pregnancy, an increased intake of this mineral is recommended to cover deposition of approximately 18 mg day, most of which is in fetal liver. The UL (10 000 mg day) is the same as for nonpregnant women, based on the need to prevent the liver damage that occurs with high intakes. Recommended intakes of selenium for adults are based on the criterion of maximizing plasma glutathione peroxidase activity. Based on an...

Hdl Ldl Vldl

Regulation of insulin sensitivity and fatty acid oxidation Increase of lipogenesis Stimulation of prostacyclin production by mature fat cells. Interaction with insulin in regulation of adipocyte metabolism Induction of leptin and IGF-I expression. Stimulation of lipolysis Inhibition of lipolysis. Stimulation of glucose transport and oxidation LPL activity inhibition. Induction of lipolysis Inhibition of lipolysis and stimulation of lipogenesis. Induction of glucose uptake and oxidation....

Fat Distribution and Disease Risk

Numerous studies have examined associations between fat patterning and mortality and morbidity. Since fat distribution is correlated with age as well other risk factors for disease, such as smoking, alcohol consumption, physical activity, and menopause in women, it is important to control for the effects of these variables in order to obtain an estimate of the independent effect of central obesity on morbidity. The impact of some of these correlates of fat distribution may be subtle and...

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...

Diagnosis of Cobalamin Deficiency

Cobalamin deficiency is suspected in individuals who display the typical manifestations of deficiency of the vitamin as described in the section above on the effects of deficiency. In addition to the symptoms that may be experienced by individuals that are related to anemia (easy fatigue, shortness of breath, palpitations) and neuropathy (sensory and motor disturbances and memory loss) there are features that may be detected by a physician, including skin pallor (from anemia), abnormalities in...

Iodine Deficiency and Excess Iodine Deficiency

Iodine deficiency is the most common cause of preventable mental retardation in the world. This fact, along with the recognition that iodine deficiency is not limited to remote rural populations, has stimulated agencies and governments to mobilize resources to eliminate this problem. This global effort, focusing primarily on iodization of salt for human and animal consumption, is slowly succeeding in eliminating a hidden set of disorders that have plagued mankind for centuries. Unlike many...

Innate Immune Response

Many of the studies on gut responses to gluten have been performed in the established chronic lesion. Little is known of innate responses that can elicit effects within minutes to hours of exposure to gluten. In vitro studies demonstrated an increase in the expression of HLA antigen on the cells in the surface layers of the intestinal mucosa occurring within 2-4 h after exposure to gluten. Gluten also causes the production of the proinflammatory cytokine IL-15 at the surface epithelium. IL-15...

Definition of Food Intolerance

Food intolerance can be defined as a reproducible adverse reaction to a specific food or food ingredient, and it is not psychologically based. Although this appears straightforward, there are a number of difficulties with this definition, and these are discussed below. Lack of Definition of 'Adverse Reaction' One problem with our definition of food intolerance is the lack of definition of what constitutes an adverse reaction. All eating causes reactions, which include satiety, feeling warm, the...

Biochemistry and Physiology of Galactose

The main pathway of galactose metabolism in humans is the conversion of galactose to glucose, without disruption of the carbon skeleton. The name 'galactosemia' has been associated with a syndrome of toxicity associated with the administration of galactose to patients with an inherited disorder of galactose utilization, leading to multiple clinical manifestations, including malnutrition, mental retardation, liver disease, and cataracts. The clinical manifestations are linked to specific...

Nutrition and Health Claims at Codex

Many countries use decisions of the Codex Alimen-tarius Commission (Codex) as a basis for national regulations. Codex decisions are also used by the World Trade Organization (WTO) as the basis for resolution of trade disputes between nations. In May 2004, the Codex Committee on Food Labeling adopted draft guidelines for the use of nutrition and health claims the commission officially adopted these draft guidelines in June 2004. Nutrition and health claims would not be allowed for foods for...

Effects of Diet on Chylomicron Metabolism

Diets very high in saturated fat have been associated with increased postprandial chylomicrons and chylomicron remnants compared with diets rich in n-6 polyunsaturated fats however, human experiments carried out using moderate to high fat intake have not shown significant effects of different types of dietary fat or dietary cholesterol on postprandial lipoproteins. The effects of dietary carbohydrates on postprandial lipoproteins have also been studied. Most protocols have used diets very high...

Hyperglycemia and the Glycemic Index

In contrast to the numerous processes that protect against blood glucose falling too low, there is only one that protects the body from hyperglycemia the release of insulin into the blood in response to the ingestion of food. Plasma insulin concentration, although neither its rate of increase nor its effectiveness (which depend on intrinsic physiology of the B cells and peripheral insulin sensitivity, respectively), is in large part determined by the increase in arterial blood glucose...

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...

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...

Essentiality and Metabolic Functions of Chromium

The essentiality of trivalent Cr in human nutrition was documented in 1977 when diabetic signs and symptoms of a patient on total parenteral nutrition (TPN) were reversed by supplemental Cr. Diabetic symptoms, including elevated blood glucose, weight loss, impaired nerve conduction, brain disorders, and abnormal respiratory quotient, that were refractory to exogenous insulin were reversed following increased intake of the essential nutrient Cr. Upon daily addition of supplemental Cr to the...

Metabolism of Dietary Nucleic Acids in Humans

The normal human diet is rich in both DNA and RNA since food is derived from once-living organisms. The metabolism of these exogenous nucleic acids follows a similar pattern to the intra-cellular process described previously, but the bacterial flora of the intestine are the first point of attack. This digestion is rapid. Studies in pigs (confirmed by later studies in humans) demonstrated that up to 50 of radiolabeled dietary purine was degraded and lost as carbon dioxide gas within 30 min, with...

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...

Iodine Deficiency Disorders

The effects of iodine deficiency on the growth and development of a population that can be prevented by correction of iodine deficiency, denoted by the term IDD, are evident at all stages, including Figure 2 A mother and child from a New Guinea village who are severely iodine deficient. The mother has a large goiter and the child is also affected. The larger the goiter, the more likely it is that she will have a cretin child. This can be prevented by eliminating the iodine deficiency before the...

Hepatic Glucose Metabolism

During infection, the liver increases glucose production to defend against hypoglycemia. In fact, the increase in hepatic glucose production is the major reason why patients with infection have an elevated blood glucose concentration. For example, patients with active malaria can have an increase in fasting glucose concentration due to an increase in gluconeo-genesis and overall glucose production. Approximately 75 of cancer patients, like patients with infection, also have an elevated rate of...

Nutritional Adequacy

In English-speaking North America, dietary reference intakes (DRI) have been issued by the Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. Nutritional adequacy is defined as meeting nutrient needs such as the recommended dietary allowances (RDAs) or the adequate intakes (AI), while avoiding excess and staying below the tolerable upper levels of intakes (UL) and keeping within the macronutrient ranges specified by expert groups. Similar reference standards are...

Bowel Rest

PN is often used when continued use of the gastrointestinal tract may not be advisable. PN may be selected for inflammatory bowel disease patients with severe acute exacerbations or for perioperative care. For patients with Crohn's disease, PN may aid the management of complications such as intestinal obstruction, fistula formation, short bowel syndrome, and severe diarrhea. Otherwise, enteral nutrition support is frequently used for nutrition support in inflammatory bowel disease with...

Timing of Reaction and Delayed Reactions

Most allergic reactions to foods occur within minutes of ingestion of the food. However, sometimes a reaction may be delayed. This is best documented in cow's milk protein allergy, in which three types of reaction are recognized early skin reaction, early gut reaction, and late reaction. An affected individual usually exhibits only one of these types of reaction. In the early skin reaction group, symptoms begin to develop within 45 min of cow's milk challenge. Almost all patients in this group...

Fecal Excretion

The only route of significant cholesterol excretion is through fecal excretion of neutral sterols. The combination of unabsorbed biliary and dietary cholesterol accounts for the total neutral sterol output and under most conditions is 750-850 mg per day. Dietary patterns or drugs that interfere with intestinal cholesterol absorption result in increased fecal neutral steroid excretion. In the colon, intestinal bacteria are able to metabolize cholesterol to a variety of neutral steroids as well...

Naturally Occurring Carcinogens

It has been estimated that the total number of known chemicals exceeds 7 million, and that the great majority are naturally occurring. Although only a very small proportion (perhaps less than 0.01 ) of these chemicals have been tested for carcinogenic potential in laboratory studies, a high proportion (as high as 50 in some evaluations) have been found to be positive. Therefore, even allowing for the imperfect selection and testing process, it is likely that there are a very large number of...

Macronutrients

Energy The dietary energy intake recommended for healthy adults of normal weight (body mass index between 18.5 and 25kgm2) is the energy required to maintain energy balance, considering gender, age, weight, height, and level of physical activity. The energy requirements of lactating women include the additional energy that is necessary for milk production. The stage and extent of breastfeeding affect the incremental energy requirements for lactation. The energy density of human milk is mainly...

Pharmacological Uses and Toxicity of Vitamin B6 Supplements

Supplements of vitamin B6 ranging from 25 to 500 mg day, and sometimes higher, have been recommended for treatment of a variety of conditions in which there is an underlying physiological or biochemical mechanism to justify the use of supplements, although in most cases there is little evidence of efficacy. Such conditions include postnatal depression, depression and other side effects associated with oral contraceptives, hyperemesis of pregnancy, and the premenstrual syndrome. Supplements have...

Nutritional Management Acute Liver Failure

The nutritional status of someone with acute liver failure versus chronic liver failure can differ greatly. The primary goal of the nutritional management in acute liver failure is supportive. An increase in nausea, vomiting, and anorexia may be associated with acute liver disease, which may result in decreased oral intake. If normal nutritional status prior to the insult is assumed, the patient will have a much higher nutritional reserve than that of a patient in chronic liver failure. Energy...

Dietary Sources High Intakes and Antimetabolites

As can be seen from Table 1, different types of foods differ considerably, not only in their total contribution to nicotinic acid equivalents, but also in the ratio of the contribution from preformed niacin and from tryptophan. In a typical Western diet, it has been calculated that if the 60 mg tryptophan 1 mg niacin formula is applied, then preformed niacin provides about 50 of the niacin supply in the diet. In practice it seems possible for all of the niacin requirement to be provided by...

Principles of Management

The first principle is to identify the underlying functional, physiological, or pathological cause of the malnourished state. If the condition is curable, then the management issues are simplified. For instance, if a person is dehydrated because of hyperglycemic diuresis in uncontrolled diabetes mellitus, the short-term management involves administration of exogenous intravenous fluids to restore normal hydration however, restoring adequate diabetic control to the patient would be the long-term...

Introduction

The term protein deficiency represents a state of deficit in body protein or one or more of the essential amino acids. Thus, the term protein deficiency can also be considered synonymous with negative nitrogen balance. The deficiency can result from a protein-deficient diet or other diseases and, in general, can also result from a global deficit of food. While protein-energy malnutrition is the more common form of protein deficiency, in general the features are comparable to those seen with...

Energy Cost of Activities

Results from a number of longitudinal studies have shown that the cost of non-weight-bearing activity changes little until very late pregnancy. From approximately 35 weeks, the gross costs (which include changes in BMR) increase by approximately 11 and net costs by approximately 6 . The gross and net costs of weight-bearing exercise (treadmill walking and standardized step testing) remain fairly constant during the first half of pregnancy and then increase progressively by approximately 15-20...