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...

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...

Info

Combined increased weight loss and maintenance Figure 2 Ways to increase average long-term weight loss maintenance achieved in experimental research. Very low-calorie diets Very low-calorie diets (VLCDs) are dietary regimens that provide approximately 400-600 kcal per day usually as a liquid formula. VLCDs have been shown to produce excellent initial weight losses ( 20 kg at 12 weeks) this effect is due in part to the degree of caloric restriction and in part to decreased dietary variety and...

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...

Glucose Mood and Mental Function

The possibility that ingesting glucose can alter mood and improve mental function has generated considerable research interest. However, there is space here only to summarize and interpret the key findings and controversies. The interest in glucose arises from two observations first, that the primary source of energy for brain function is glucose, and, second, that mental function and mood deteriorate when blood glucose concentration falls below basal physiological levels (hypoglycemia < 3.6...

Special Populations at Risk of Low Vitamin D Intakes and Low Status

Several at-risk subpopulations for poor vitamin D status have been identified. Except for migrant populations, these groups have already been mentioned previously. Elderly individuals prefer to stay indoors and many are actually 'shut-ins' who have little opportunity for direct sun exposure (UV-B does not penetrate glass windows in rooms or solaria). The shut-ins are most likely to be deficient in vitamin D and calcium and at increased risk for fractures of the hip, especially with increasing...

Other Causes of Hyperhomocysteinemia

Other pathophysiological causes of hyperhomocys-teinemia include renal dysfunction and hypothyroid-ism. The kidney is a major site of homocysteine metabolism and renal disease leads to a significant reduction in the body's overall capacity to metabolize this amino acid. The resulting moderate to severe hyperhomocysteinemia can be attenuated, in part, by high-dose B vitamin supplements, which putatively maximize the residual renal metabolism, as well as the metabolic capacities of the extrarenal...

Alcohol and Facial Flushing

Genetic variations in ADH and ALDH may explain why particular individuals develop some of the pathologies of alcoholism and others do not. For example, up to 50 of Orientals have a genetically determined reduction in ALDH2 activity ('flushing' phenotype). As a result, acetaldehyde accumulates after ethanol administration, with plasma levels up to 20 times higher in people with ALDH2 deficiency. Even small amounts of alcohol produce a rapid facial flush, tachycardia, headache, and nausea....

Methods for Estimating Dietary Intake at the Household Level Household Budget Surveys

Techniques for estimating intake at the household level include the food account method, the inventory method, the household record, and the list recall method. These methods measure all foods and beverages available for consumption by a household or family group during a specified time period of between 1 and 4 weeks, although some last for 23 months. Wastage factors are sometimes applied. Household surveys provide data for per capita consumption of foods or nutrients, not intake for specific...

Body Weight and Energy Balance

The effects of alcohol on body weight are dependent upon the timing and amount of alcohol consumption in relation to meals and on the presence or absence of organ damage, in particular alcoholic liver disease (Table 2). Whereas body weight is usually unaffected by moderate alcohol consumption, chronic alcoholics who drink daily while substituting alcohol for other dietary constituents lose weight due to the energy neutral effect of alcohol in the diet. Moderate drinkers on weight loss regimens...

Cosmetic Problems

Orthopedic problems Flat feet and knock knee, perhaps related to the excess weight and need to internally rotate the knees to accommodate fat thighs when bringing the legs together, are common and can lead to ungainly gait. Slipped upper femoral epiphysis is a more serious problem, which is particularly common in overweight young adolescents and may also be associated with hormonal abnormalities such as hypothyroidism. Skin problems Intertrigo, seborrheic eczema, and thrush are common in the...

Designer Foods

An important direction in the development of functional foods is the combination of numerous ingredients to achieve a specific set of goals, rather than efforts to uncover the potential benefits of a single food source. Infant formula was probably the first area for designer foods of this type, because of the profound influence of nutrients on the developing brain and immune system. The addition of DHA to infant formula for enhancing brain and visual development, the alteration of allergenic...

Invasive Bacteria Salmonella Infections

Background Salmonellae are the most common known cause of bacterial FP in developed (and possibly less well-developed) countries of the world. Other bacteria such as campylobacter commonly cause GE but not necessarily FP. There are a large number of serotypes of salmonella. They are typed according to their somatic O or flagellar H phases 1 and 2 antigens according to the Kauffman-White scheme and are generally named after a geographical location. Further typing, usually by phages, can be done...

Examples of Specialist Roles in Dietetics Renal Dietetics

Renal dietitians are usually attached to specialized renal units and are an integral part of the team involved in the treatment of people suffering from varying degrees of renal impairment, whether acute or chronic. In the United States, there is a legal requirement related to funding of patient care that states that a qualified dietitian must be part of the professional team that develops long- and short-term care plans for renal patients. The dietitian, together with the nephrologist, has...

Dietary Selenium Absorption and Mechanisms of Incorporation of Selenium into Selenoproteins

Rich food sources of selenium in human diets include Brazil nuts, offal, shellfish, and some other types of fish, although there is uncertainty about the extent of selenium bioavailability in some foods, which may in turn be linked to problems of mercury contamination. In the United Kingdom, cereal foods account for approximately 20 of total selenium intake, whereas meat, poultry, and fish account for 30-40 . Selenium is readily absorbed, especially in the duodenum but also in the caecum and...

Inborn Errors of Fructose Metabolism

Several genetically based abnormalities in fructose metabolism have been described in humans. Fructo-kinase deficiency leads to high levels of fructose in the blood and urine. In the absence of fructokinase, fructose can be metabolized to fructose-6-phosphate by hexokinase (EC 2.7.1.1), although at a low rate. Consequently, no serious health problems are associated with this abnormality. The aldolase A, B, and C enzymes catalyze the reversible conversion of fructose-1-diphosphate into...

Folklore and Evidence Fact or Fiction Totality of the Evidence

Food folklore cannot be taken as fact without evidence. Single studies are usually inadequate for demonstrating cause-effect relationships, and no single study alone is enough to prove that something is fact or folklore. It is important to consider the totality of evidence and the type and quality of the available research. When many different types of evidence are all supportive of a relationship, the weaknesses of individual studies are mitigated and causal inference is strengthened. Ideally,...

Hormonal Response to Injury Infection and Cancer

Infection, cancer, or any injury to the body result in an increase in counterregulatory hormones as well as insulin concentration. As a result of cancer, sepsis, or injury, many patients develop the syndrome of insulin resistance even though they had no history of diabetes prior to cancer. In cancer patients, when the overall injury is smaller, many studies have failed to demonstrate an elevation in counterregula-tory hormones. Mild elevations in cortisol concentrations may contribute to the...

High Intensity Exercise and Strength Training

High-intensity exercise requires energy utilization rates that exceed the oxidative capabilities of the muscle. Activities such as sprinting require the anaerobic resynthesis of ATP to produce and maintain high levels of muscular force and are therefore limited in duration. Strength training also relies heavily on anaerobic energy sources and requires high force production by specific muscle groups. Adaptations to High-Intensity Exercise and Strength Training The main alterations that occur in...

Nutrient Dilution

Adding sugars to foods will increase their energy density (kcal per unit weight), and since they do not add nutrients, this will result in a net reduction in nutrient content per kcal. This dilutional effect is evidenced in the increasing per cent of individuals who do not meet their RDA for one or more micro-nutrients as their consumption of added sugars increase. In adolescents, soft drinks tend to displace nutrient-rich milk and juices. Data from the US population indicate that this...

Resolved and Unresolved Issues

Some of the issues that researchers have encountered in their attempt to uncover the mystery of the dietary factors linked to cancer include the difficulty of distinguishing the importance of parts of dietary factors from the overall effect of each dietary factor (e.g., total dietary fat intake compared with type of dietary fat intake). In a meta-analysis in 1990 of 12 case-control studies of dietary fat intake and cancer, 4 studies observed a significant positive association, 6 uncovered...

Bone Gla proteins

Protein S together with two other Gla proteins, osteocalcin (OC or bone Gla protein) and matrix Gla protein (MGP), play a variety of only partly understood roles in bone and other mineralized tissues. Of these proteins, only OC is produced solely and specifically by mineralized tissue, whereas the other two (or at least their mRNA templates) are more widespread and occur also in soft tissues. OC is synthesized specifically by osteoblasts and odontoblasts, and it accounts for ca. 15-20 of the...

Hypogammaglobulinemia

Common variant hypogammaglobulinemia is a defect of acquired immunity. Most of these patients have diarrhea and malabsorption. Patients are prone to G. lamblia infections and small bacterial overgrowth. The disease may result in intestinal inflammation and is associated with celiac disease, refractory sprue, and Crohns' disease. Stool cultures for bacteria, ova, and parasites together with duodenal aspirates may be needed. Duodenal biopsies show loss of plasma cells in the lamina propria....

Edible Plants and Phytochemicals

Because their consumption is known to enhance health, vegetables, fruits, cereal grains, nuts, and seeds are the most widely researched functional foods. The health benefits of a plant-based diet are usually attributed to the content of fiber and of a variety of plant-derived substances (phytonutrients and phytochemicals) with antioxidant, enzyme-inducing, and enzyme-inhibiting effects. Some phyto-chemicals may also exert their health effects by modifying gene expression. Carotenoids, for...

Iron and Zinc Homeostasis

Iron is the most abundant element on Earth. Despite this it is the most common micronutrient deficiency on Earth with up to 50 of all children under 5 years and pregnant women in developing countries affected. The ability of iron to both bind oxygen and to donate and accept electrons ensures that it has a central role in cellular energy metabolism. The utility of this redox potential is, however, counterbalanced by the propensity of iron to generate free radicals and damage cell membranes...

Macular Degeneration and Cataracts

The eye is at particular risk of oxidative damage due to high oxygen concentrations, large amounts of oxidizable fatty acids in the retina, and exposure to ultraviolet rays. In Western countries, age-related macular degeneration (AMD) is the leading cause of blindness among older people. Cataracts are also widespread among the elderly and occur when the lens is unable to function properly due to the formation of opacities within the lens. These develop when proteins in the eye are damaged by...

Clinical Manifestations and Diagnosis of Gall Stone Disease

Approximately 80 of people with gall stones are asymptomatic. The presentation of gall bladder disease can be episodic pain when a brief cystic duct obstruction occurs or acute cholecystitis when the obstruction lasts longer and results in local and relatively extensive inflammation and edema. The complications include infection of the biliary system (cholangitis) and pancreatitis. Pain related to the gall bladder is usually felt in the right upper quadrant or in the epigastrium. It may radiate...

Diseases of Carbohydrate Metabolism

Fructose intolerance and essential fructosuria Fruc-Fructose intolerance and essential fructosuria are genetic defects of fructose metabolism. Fructose intolerance is an autosomal recessive disease, caused by a genetic defect in fructose 1-phosphate aldolase (aldolase B) in the liver. The symptoms of aldolase B deficiency occur when the infant is exposed to fructose. Aldolase B deficiency results in phosphate depletion and fructose 1-phosphate accumulation in the liver. Consequently,...

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...

Starvation And Fasting

J E Bines and R G Heine, University of Melbourne, 2005 Elsevier Ltd. All rights reserved. During a normal 24-h day the body's essential cellular and organ functions remain homeostatic despite intermittent nutrient intake and changing metabolic demand. A highly sophisticated and integrated system provides the metabolic adaptation for these normal changes in substrate provision and utilization. A basic knowledge of the normal metabolic responses in the feeding-fasting cycle is pivotal to the...

Caveats for the Diagnosis of Secondary Undernutrition

Undernutrition due to disease and dysfunction obviously requires establishment of the following (1) the existence of deficiencies and (2) that factors other than underconsumption are influencing the deficiency states. The body composition standard is a body mass index (BMI) of < 18.5 kgm 2. With the worldwide pandemic of overweight, recent weight loss of 10 or more of usual body weight may be a more sensitive and reliable indicator of an incipient undernutrition problem. Weight problems...