Digestion and Metabolism

During the transit of digested food material through the gastrointestinal tract many changes occur in the intestinal lumen that could influence nutrient bioavailability. Digestion of food constituents is an important aspect of nutrient bioavailabil-ity. The secretion of acid into the stomach following food ingestion activates certain digestive enzymes, as well as creating an acidic environment that influences mineral solubility and extraction from food. In this regard, the choice of a mineral...

Further Reading

Becher G (1998) Dietary exposure and human body burden of dioxins and dioxin-like PCBs in Norway. Organohalogen Compounds 38 79-82. Buckland SJ (1998) Concentrations of PCDDs, PCDFs and PCBs in New Zealand retain foods and assessment of dietary exposure. Organohalogen Compounds 38 71-74. Environmental Protection Agency (2001) Dioxin Scientific Highlights from Draft Reassessment. Washington, DC US Environmental Protection Agency, Office of Research and Development. Food and Drug Administration...

Growth Hormone

Basal and pulsatile secretion of growth hormone (GH) is increased, with a peripheral resistance to its effects. Serum GH levels are elevated in 60 of patients, particularly in the most severe cases. This is due to decreased feedback from lowered serum concentrations of insulin-like growth factor 1 (IGF 1) and to increased serum levels of ghrelin. Growth hormone levels do not rise normally after L-dopa or insulin hypoglycemia, but there may be an unexpected rise in GH blood levels after...

Absorption Transport and Storage

Riboflavin (vitamin B2) is not synthesized by higher animals. Therefore, it is an absolute dietary requirement for the synthesis of certain essential coenzymes that are needed for intermediary metabolism in nearly all living cells. Riboflavin must be transported from the food sources within the gastrointestinal tract, across the gut wall into the circulatory system, and thence into the cells of each organ. This transport process occurs against a concentration gradient, in order to ensure the...

Best Practices to Prevent Osteoporosis

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

Hunger and Eating Behavior

If hunger is biologically useful and a subjective experience that indicates a depleted nutritional state, then a close correspondence between hunger and eating would be expected. So hunger should be either a necessary or a sufficient condition for eating to occur. However, this is not invariably the case. Instances of people deliberately refraining from eating in spite of hunger (fasting for moral or political conviction) show hunger not to be a sufficient condition. And examples in research...

Magnesium

More than half of the magnesium found in the body is located in bone. In addition to its presence in bone, magnesium is important in calcium metabolism and bone health because it is required for parathyroid hormone secretion. Parathyroid hormone (PTH) is integral to bone health because it increases the production of the active form of vitamin D (1,25-dihydroxyvitamin D) and plays a role in the tubular reabsorption of calcium and phosphorus. Although magnesium deficiency is associated with...

Micronutrients and Physical Activity

Many micronutrients play key roles in energy metabolism, and during strenuous physical activity the rate of energy turnover in skeletal muscle may be increased up to 20-100 times the resting rate. Although an adequate vitamin and mineral status is essential for normal health, marginal deficiency states may only be apparent when the metabolic rate is high. Prolonged strenuous exercise performed on a regular basis may also result in increased losses from the body or in an increased rate of...

Pregnancy and Fetal Growth

Since World War II, the role of maternal nutrition in fetal growth and development has been extensively studied in the context of protein-calorie malnutrition. The role of n-3 fatty acids has only recently come into focus, despite the evidence of its importance having been demonstrated in a series of studies between 1928 and 1930 involving rats and primates. Lipid nutrition during pregnancy and lactation is of special relevance to human development, because brain development in the human takes...

The Large Intestine

Microorganisms occur throughout the alimentary tract but in healthy individuals their numbers and diversity are maintained within strict limits by the combined effects of intraluminal conditions, rapid transit, and host immunity. The colon and rectum, however, are adapted to facilitate bacterial colonization, and the typical adult human colonic microflora has been estimated to contain about 400 different bacterial species. The largest single groups present are Gram-negative anaerobes of the...

Christianity

Early Christians observed Mosaic dietary laws. However, the concept of uncleanliness described in Leviticus was rejected by St. Paul and, as Christianity spread across cultural and geographical boundaries, dietary laws largely disappeared (except in the Eastern Orthodox Church). Food, rather than being a way of marking separateness, became a symbol of the communality of religious experience. The celebration of the Eucharist, or Communion, with ritual sharing of bread and wine, though it varies...

Dose

The WHO has published global guidelines for iron supplementation and recommends daily prophylactic iron supplementation with 60 mg of iron for all women in developing countries in the second and third trimesters of pregnancy (Table 1). In other countries, iron supplementation is recommended only for women with proven iron-deficiency anemia (in Great Britain) or for women with low pre-pregnancy iron stores (in Canada). The efficacy of maternal iron supplementation increases with daily iron doses...

Degradation Turnover and Factors that Induce Increased Requirements for Vitamin C

The instability of vitamin C in air, and especially in neutral or alkaline aqueous solution, is attributable to the fact that in the presence of oxygen or other oxidizing agents it readily undergoes two successive one-electron oxidation steps to produce dehydro-ascorbate. Since the oxidation products are also unstable and undergo an irreversible lactone ring opening to diketogulonic acid, the vitamin is very easily destroyed, both in foods and (to a lesser extent because of efficient recycling...

Fish Minerals

The approximate amounts of selected minerals contained in fish are given in Table 8. The first point to note is that all kinds of finfish and shellfish present a well-balanced content of most minerals, either macroelements or oligoelements, with only a few exceptions. Sodium content is low, as in other muscle and animal origin foods. However, it must be remembered that sodium is usually added to fish in most cooking practices in the form of common salt also, surimi-based and other manufactured...

Egg Cholesterol

Eggs are one of the richest sources of dietary cholesterol, providing 215 mg per large egg. In the 1960s and 1970s the simplistic view that dietary cholesterol equals blood cholesterol resulted in the belief that eggs were a major contributor to hypercholesterolemia and the associated risk of cardiovascular disease. While there remains some controversy regarding the role of dietary cholesterol in determining blood cholesterol levels, the majority of studies have shown that saturated fat, not...

Formation of Ketone Bodies

It is well established that in humans and other mammals the only organ that contributes significant amounts of ketone bodies to the blood is the liver this organ, unlike peripheral tissues, is unable to utilize ketone bodies to any appreciable extent. More recently it has been found that during the suckling period (high-fat diet) the intestine also has the capacity (about 10 of the liver) to produce ketone bodies. Whether ketone bodies are used in situ or are transported via the portal blood to...

Leptin ob Protein

For 40 years, scientists searched for a mechanism by which the brain could monitor body fat deposition in order to keep an animal's body weight constant. In 1994, a gene that controlled the expression of a protein produced by adipose tissue was identified. Circulating levels of this protein (the ob protein) could be measured in normal weight mice. However, in obese ob ob mice, which display marked overeating, this protein was absent due to a mutation of the ob gene. A series of studies...

Adequacy of Zinc in the National Food Supply

As described above, the nature of the food supply will provide some information on the likelihood of risk of Table 3 Adequacy of dietary zinc in the food supply in major developing country regions, as compared to North America Adapted with permission from Food and Nutrition Bulletin (2004) (suppl 2) 25 S135. International Zinc Nutrition Consultative Group (Brown KH, Rivera JA, Bhutta Z, Gibson RS, King JC, Ruel M, Sandstrom B, Wasantwisut E, Hotz C, Lonnerdal B, Lopez de Romana D, and Peerson...

Adequate Inadequate and Excess Sodium

It is unlikely that adult daily maintenance requirement exceeds 0.6mmolperkg body weight and could well be below this in many mammals. Newborn, growing, pregnant, or lactating animals have increased requirements. The appropriate sodium intake for humans remains controversial with some cultures managing on less than 1 mmol per day, while Western intakes may be in the range 200-300 mmol per day, more where processed foods are heavily consumed. There has been insufficient awareness among...

Aluminum Deposition in Tissues

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

Acid and Alkali Load

The sources of acids (and alkalis) are from the diet and metabolism. The major potential source of acid is CO2 ('volatile acid' eqn 4 ) generated by oxidative metabolism a total of 12-20 mol of CO2 are produced daily. Other metabolic products include lactic acid, other organic acids, and urea, the synthesis of which produces H+. Because of its role in the metabolism of lactic acid and in the synthesis of urea, the liver plays a major role in acid-base home-ostasis that is often not appreciated....

Amino Acid Biosynthesis

The essential (indispensable) amino acids must be supplied in the diet because their carbon skeletons cannot be synthesized in the human body, whereas the nonessential amino acids can be synthesized from common intermediates of the central metabolic pathways within the cell (i.e., glycolysis, the pentose phosphate pathway and the TCA cycle). As long as the keto-analogs are present, almost all amino acids can be generated by the process of transamination. The exceptions are threonine and lysine....

Aging and Renal Function

The serum concentration of Pi increases with a physiological decline in renal function associated with aging (but not renal disease per se). Healthy individuals excrete approximately 67 of their absorbed phosphate via the urine and the remainder via the gut as endogenous secretions. As the glomerular filtration capacity of the kidneys declines, the serum Pi concentration increases and more Pi is retained by the body. PTH secretions increase but the typical serum PTH concentrations, although...

Altering Gut Flora

The concept of manipulating microflora to enhance the positive aspects of the GI tract has become a more focused endeavor. However, this concept is not new. The early recognition of fermented foods offering health benefits dates back to the early 1900s. Eli Metchnikoff was the first to recognize this benefit when he observed the long lives and good health of Bulgarian peasants and associated this with the large amounts of milk soured with lactic acid bacteria (LAB) they consumed. Since then...

Anthropometry

For routine clinical use, anthropometric measurements (circumference measures and skinfold thickness) have been preferred due to ease of measurement and low cost. Waist circumference and the waist-hip ratio measurements are commonly used surrogates of fat distribution, especially in epidemiology studies. Waist circumference is highly correlated with visceral fat and was recently included as a clinical risk factor in the definition of the metabolic syndrome. Specifically, waist circumferences...

Antioxidant and Biomarker Evidence from Intervention Studies in Humans

There are limited data from diet-controlled randomized crossover studies of humans on tea and other flavonoid-containing foods. Most intervention studies, apart from design considerations, suffer from lack of diet control, making them difficult to interpret. Results from intervention studies that employ dietary recalls, food records, and self-administered diets are notorious for introducing error that can mask treatment effects. Clinical studies in humans have focused on the antioxidant...

Assessment of Growth as an Indication of Adequate Nutrition

Assessment of growth in weight, length and head circumference is an internationally accepted measure of health and nutritional status of infants, albeit not an indicator that is nutrient specific. The interpretation of growth measures requires comparison with reference data from normal populations of infants that have been complied into growth charts with centiles indicated. The growth charts from the Center for Disease Control in the United States as revised in 2000 growthcharts charts.htm),...

Assessment of Binge Eating

A binge episode is defined as the consumption of a large amount of food within a discrete period of time, accompanied by a sense of loss of control over eating. Researchers and clinicians have agreed that loss of control involves the subjective feeling that one cannot stop eating or control what or how much is being eaten. However, there has been much less agreement about the size and duration of a binge eating episode. Specifically, there is no consensus as to what constitutes a large amount...

Assessment of Manganese Status

Reliable biomarkers for the assessment of manganese status have not been identified. Whole blood manganese concentrations are reflective of soft tissue manganese levels in rats however, it is not known whether a similar relationship holds for humans. Plasma manganese concentrations decrease in individuals fed manganese-deficient diets and are slightly higher than normal in individuals consuming manganese supplements. Lymphocyte MnSOD activity and blood arginase activity are increased in...

Beyond Adaptation through Mass Action

There is in fact a built-in stabilizing mechanism in the overall homeostatic system for body weight. Any imbalance between energy intake and energy requirements will result in a change in body weight that, in turn, will alter the maintenance energy requirements in a direction that will tend to counter the original imbalance and hence be stabilizing. The system thus exhibits 'dynamic equilibrium.' For example, an increase in body weight will be predicted to increase metabolic rate (on the basis...

Benefits of Low Glycemic Index Carbohydrates on Diabetic Control

This is the area in which there is most evidence of clinical efficacy. Two independent systematic reviews of the world evidence demonstrated the efficacy of low glycemic index diets on glycemic control in both type 1 and type 2 diabetes. Clinical studies have shown that after 3 months of a diet containing low glycemic index carbohydrates, glycemic control is improved in both type 1 and type 2 diabetes. With low glycemic diets, postprandial glucose and insulin concentrations decrease in type 2...

Body Weight Body Composition and Growth

People living in areas of high climatic seasonality are well aware of the nutritional impact of seasonality, as indicated by the language they use to define such seasonal stress periods. The Massa of Cameroon call the month of July in the middle of the wet season the month of 'Did you call me for food ' and they have a word to define 'hunger with threat,' when food shortage has been too long and life is in danger. However, it was not until the 1950s that the scientific community started to...

Brain Development

During the fetal and neonatal period, the availability of choline to tissues fluctuates because of the varied dietary intake of choline among neo-nates and the slower oxidation of choline during the first weeks of life. However, ensured availability of this amine appears to be vital to infants because organ growth, which is extremely rapid in the neonate, requires large amounts of choline for membrane biosynthesis. Choline is also particularly important during the neonatal period because it...

Breast Milk

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

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....

Carcinogenicity in Animals

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

Care in the Community

Most people with Down's syndrome live in the community some live with parents or caregivers, but adults often live independently or semi-independently. Many people with Down's syndrome can learn about healthy eating and manage their own diets. A dietitian's role in a community learning disability support team is likely to encompass not only individual assessment but also teaching and educating people with Down's syndrome as well as parents, caregivers, and other professionals. See also Aging....

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...

Chronic Liver Disease

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

Chronic Bronchitis

Definition and etiology Chronic bronchitis is defined by the presence of chronic bronchial secretions sufficient to cause expectoration occurring on most days for a minimum of 3 months for 2 consecutive years. It became recognized as a distinct disease in the late 1950s associated with the great British Smog. It develops in response to long-term irritants on the bronchial mucosa. Important irritants include cigarette smoke, dust, smoke, and fumes other causes include respiratory infection,...

Cholesterol

The interest in cholesterol as a substance that is related to psychological well-being stems back to the 1980s. During this period, a number of epi-demiological studies found that individuals with low cholesterol levels were more prone to aggressive behavior and at greater risk of suicide and violent death. In addition, it was found that non-human primates increased their incidence of aggressive behavior when kept on a low-cholesterol diet. In terms of neuropsychological function, a number of...

Classifications

Various food components have been recognized to have prebiotic activity, including various fermentable carbohydrates (lactulose, gums, lactilol, soyoligosaccharides, galacto-oligosaccharides Xylo-oligosaccharides. However, the best studied of these have been those classified as dietary fructans. Dietary fructans can either be derived from naturally occurring oligosaccharides or can be artificially synthesized. These carbohydrates contain one or more fructosyl-fructose links that make up the...

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...

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...

Concept and Definition

The concept of functional foods derives from the observation that certain foods and beverages exert beneficial effects on human health that are not explained by their nutritional content (i.e., macronu-trients, vitamins, and minerals). The definition of functional foods varies among countries for reasons that are historical, cultural, and regulatory. In its broadest use, functional foods are food-derived products that, in addition to their nutritional value, enhance normal physiological or...

Clinical Manifestations Diagnosis and Treatment

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

Conclusion

The glycemic index of a diet is an indicator of postprandial metabolism, which is important in contributing to cardiovascular risk. Dietary carbohydrates are absorbed and metabolized differently and therefore influence postprandial glucose, insulin, and NEFA concentrations differently. In Western society, the proportion of the day that we spend in the postprandial state is increasing as the tendency to snack throughout the day replaces sit-down meals. The known detrimental consequences of high...

Confounding Effects of Infection on Laboratory Assessment

As already indicated, many confounding effects of infection have been observed in many laboratory tests for nutritional status. For protein status, confounding effects of infection are reported for almost all laboratory tests, excluding that for total serum protein. In particular, serum albumin, plasma transport protein, and fibronectin levels decrease because of the increase of acute phase proteins. For vitamin A, severe systemic infections (e.g., pneumonia, bronchitis, diarrhoea, septicaemia,...

Conclusions

Home nutritional support, including both oral and artificial (enteral and parenteral) methods of feeding, is an important modality of treatment that is being used for an increasing number of people with disease and disability who are managed in the community. The identification of individuals who are at increased risk of malnutrition and who may benefit from additional nutritional support is a vital first step, which can be undertaken using a validated screening tool (such as MUST Figure 1)....

Daily Regulation of Body Water

The body's total body water content is normally maintained within a small window of fluctuation on a daily basis by intake of food and drink to balance the excretion of urine and other losses. Hyperhydration is corrected by an increase in urine production and hypohydration by an increase in water intake via food or drink consumption initiated by thirst. Most of our water intake is related to habit rather than thirst, but the thirst mechanism is effective at driving intake after periods of...

Correlates and Possible Determinants of Fat Distribution

A large number of studies have examined correlations between fat distribution and genetic, behavioral, and physiological variables. Many factors, including heredity, overall fatness, gender, age, smoking, alcohol consumption, physical activity, and ethnicity, are associated with either an android or a gynoid shape. The underlying reasons for the observed associations between these variables and fat patterning remain to be elucidated. Correlates of fat distribution are important to understand...

Daily Recommended Dietary Allowance of Vitamin A

The Food and Nutrition Board of the Institute of Medicine revised the Recommended Dietary Allowance (RDA) of vitamin A in 2001 as 900 retinol activity equivalents (RAE) for men and 700 RAE for women. The RAE was introduced to avoid the ambiguity of international units (IU), which arises because 1IU of vitamin A (0.3 mg) and 1 IU of the vitamin A precursor (provitamin A) all-trans- 3-carotene (0.6 mg) do not have the same biological activity. Rather, 6 IU of -carotene and 12 IU of mixed...

Crohns Disease

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

Current Vegetarian Eating Patterns and Practices

Until about 40 years ago, in Western countries virtually all of the common vegetarian eating patterns involved avoidance of animal flesh (meat and poultry) categorization of vegetarian patterns was relatively straightforward and consisted simply of differentiating between those who ate no animal foods at all (vegan vegetarians), those who also consumed milk and milk products (lacto vegetarians), and those who ate eggs as well (lacto-ovo vegetarians). This simple categorization scheme broke down...

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...

Coronary Heart Disease

Most epidemiologic studies and clinical trials using n-3 fatty acids in the form of fish or fish oil have been carried out in patients with coronary heart disease. However, studies have also been carried out on the effects of ALA in normal subjects and in patients with myocardial infarction. The hypolipidemic effects of n-3 fatty acids are similar to those of n-6 fatty acids, provided that they replace saturated fats in the diet. n-3 fatty acids have the added benefit of not lowering...

Definition and Etiology

The word 'asthma' originates from an ancient Greek word meaning panting. It is a chronic obstructive disease characterized by tracheobronchial hyperreac-tivity leading to paroxysmal airway narrowing, which may reverse spontaneously or as a result of treatment. The smooth muscle surrounding the bronchi has an abnormally increased reaction to stimuli. Specific bronchial stimuli include inhaled allergens (e.g., house-dust mite, pollen, and moulds). Nonspecific bronchial stimuli include upper...

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...

Diagnostic Criteria

The behavior at the center of the disorder, binge eating, has been progressively redefined. A priority has been to separate binge eating from mere indulgence and everyday overeating. Accordingly, two features of a true binge have been identified consumption of unusually large amounts of food and an aversive sense of lack of control over eating. The size of binges varies but is typically between 1000-2000 kcal. Diagnostic schedules (such as DSM-IV and ICD-10) agree on three features that must be...

Development of Microflora

The GI tract is essentially sterile at the time of birth and bacterial colonization begins upon exposure to the environment. Progression of colonization is initially fast, followed by a gradual process of modification over the first few years of life. As the baby passes through the birth canal bifidobacteria and lactobacilli are typically acquired and rapid colonization of mainly enterobacteria occurs. The hospital environment, type of feeding, and type of delivery affect the early colonization...

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...

Diet and Physical Activity Behaviors

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

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...

Disorders of Fructose Metabolism

There are three disorders of fructose metabolism, all inherited in an autosomal recessive fashion. Fructose is widely distributed in the diet as the primary sugar in fruits, vegetables, and honey. It is also derived from sucrose and sorbitol, which are found in large variety of products, including infant formulas and intravenous fluids. The toxic effect of fructose is due to inhibition Debranching enzyme (amylo-1, 6-glucosidase) GSD IV (amylopectinosis) Branching enzyme GSD V (McArdle disease)...

Dietary Supplements

The use of nutritional supplements in athletes and in the health-conscious recreationally active population is widespread, as it is in the general population. A very large number of surveys have been published. A meta-analysis of 51 published surveys involving 10274 male and female athletes of varying levels of ability showed an overall prevalence of supplement use of 46 , but the prevalence varied widely in different sports, at different levels of age, performance etc., and in different...

Dietary Vitamin D Intakes and Low Vitamin D Status in the US

Vitamin D intakes have not been assessed in national surveys and only rarely in research investigations involving smaller sample sizes. The few studies that have estimated vitamin D intakes typically find them to be below recommended amounts, especially among the elderly and, more recently, among adults. In the US, at least, most experts think that both intakes are too low and exposures of skin to sunlight are inadequate. Role of the Diet in Providing Vitamin D The few sources of vitamin D...

Differential Diagnosis

In the majority of cases the severe and voluntary malnutrition accompanied by the typical delusion of being fat and resistance to gain weight make the diagnosis very clear. Malnutrition due to organic causes in adolescents usually has an obvious reason and the patients want to improve their nutrition. Hypothalamic tumors may rarely present with severe loss of appetite. The differential diagnosis should include the anor-exoid syndromes. In pure anorexia nervosa the weight loss is due only to...

Digestive System

Gallbladder disease The risk of gallbladder disease, particularly gallstone formation, is increased in obesity and occurs with greater frequency in women. The prevalence of gallbladder disease in obese individuals increases with age, body weight, and parity. The etiology of increased gallstones is unclear, but genetic factors play a role. Increased cholesterol production, which leads to increased excretion of cholesterol in bile, is known to occur in obesity and correlates with increases in...

Dioxins and Polychlorinated Biphenyls

Fish can also contain other organic pollutants, such as PCBs and dioxins. Whereas mercury accumulates in the muscles of larger predatory fish, PCBs and dioxins are found in the fatty tissues of fish. Most human exposure to PCBs and dioxins comes from dietary sources because they accumulate in the lipid fractions of meat, fish, milk and milk products, eggs, grains, and oils. Table 5 Concentrations of methylmercury in surveyed fish in the United Kingdom Table 5 Concentrations of methylmercury in...

Disorders of Hunger

The clinical eating disorders, anorexia nervosa and bulimia nervosa, are commonly believed to encompass major disturbances of hunger. Yet the role that hunger may play is not entirely clear. Contrary to the literal meaning of the term, 'anorexia' is not experienced as a loss of appetite. Rather, clinicians recognize that anorexics may endure intense periods of hunger during their self-restricted eating. For some, their strength in resisting intense episodes of hunger provides a feeling of...

Early Enteral Nutrition Parenteral Nutrition and Bacterial Translocation

In animal models, burns and trauma have been associated with the appearance of organisms in the mesenteric lymph nodes (MLNs). This process has been called bacterial translocation. Enteral feeding has been associated with reduced translocation in guinea pigs. In other animal studies, early enteral feeding reduced nitrogen loss and the level of cata-bolic hormones. However, human studies in patients who have been traumatized have not show any benefit of early (< 24 h) enteral feeding. In...

Effects on the Central Nervous System

Animal experiments have shown caffeine-mediated effects at the neuroendocrine level, such as increased serum corticosterone and -endorphin and decreased serum growth hormone and thyrotropin, but it is expected that habitual human consumption has only marginal or inconsistent neuroendocrine effects. Caffeine is described as a central nervous system (CNS) stimulant, and the increased formation and release of neurotransmitters such as catecholamines, serotonin, 7-aminobutyric acid, norepinephrine,...

Effect of Meal Size on Energy Expenditure

Total energy expenditure (EE) can generally be divided into three major components basal metabolic rate (BMR), thermogenesis, and physical activity (Table 1). In order for meal size to have an effect on the EE side of the energy balance equation, it must have an effect on one or more of these components. There is no evidence that meal size has an effect on BMR, which refers to the energy expended to maintain the body on a day-to-day basis. Thermogenesis broadly refers to the body's production...

Efficacy of Surgical Treatment for Obesity

Surgery is usually successful in inducing substantial weight loss in the majority of obese patients. This is achieved primarily by a necessary reduction in calorie intake. In a review of RCT comparing different treatment strategies of obesity, surgery resulted in greater weight loss (23-28 kg more weight loss at 2 years) with improvement in quality of life and comorbidities. The Swedish Obese Subjects (SOS) study demonstrated long-term beneficial effects on cardiovascular risk factors. The...

Egg Choline

Choline was established as an essential nutrient in 1999 with recommended daily intakes (RDIs) of 550 mg for Table 6 Egg mineral content per large egg Table 6 Egg mineral content per large egg USDA National Nutrient Database for Standard Reference, Release 16 (July 2003). Nutrient Data Laboratory Home Page, USDA National Nutrient Database for Standard Reference, Release 16 (July 2003). Nutrient Data Laboratory Home Page, men and 450 mg for women. The RDI for choline increases during pregnancy...

Effects on Energy Metabolism

Acute administration of caffeine produces a 5-25 increase in the basal metabolic rate. Inactive subjects exhibit a greater increase in resting metabolic rate than do exercise-trained subjects. It is concluded that endurance training seems to result in a reduced thermogenic response to a caffeine challenge. These modifications of energy metabolism were associated with significant increases in serum free fatty acids, glycerol, and lactate concentrations, whereas inconsistent findings were...

Effect of Meal Size on Metabolism

Energy homeostasis, or the state of balance, achieved by matching energy intake with energy expenditure, is partially dependent on the regulation of meal size consumed. In order for meal size to have an effect on energy metabolism, it must affect either or both components involved in the regulation of energy balance, namely energy intake and energy expenditure. Energy balance is the difference between energy ingested and energy expended over a given period of time. Consequently, energy storage...

Endogenous Formation of Choline Moiety as Phosphatidylcholine

Unless eaten in the diet, choline can only be formed during phosphatidylcholine biosynthesis through the methylation of phosphatidylethanolamine by phosphatidylethanolamine N-methyltransferase (PEMT) using S-adenosylmethionine as the methyl donor. This enzyme is most active in the liver but has been identified in many other tissues including brain and mammary gland. At least two isoforms of PEMT exist PEMT1, localized to the endoplasmic reticulum and generating the majority of PEMT activity,...

Energy Intake for Patients with Malnutrition

The diagnosis of protein malnutrition can be made when the serum albumin level is less than 2.8g dl. Many of these patients have a 20 weight loss during the preceding 3 months, or they have a reduced ideal body weight (< 90 for height). Patients at high risk for the development of malnutrition are those who are unlikely to ingest a minimum of 1500 kcal by day 5. There are currently only three studies that support the importance of energy intake in malnourished patients. Elderly hospitalized...

Emerging Nutrition and Health Issues

Several emerging health issues that are related to dietary intake and lifestyle choices have made it essential to track eating habits and nutritional status over time. For example, obesity is an escalating epidemic through the world among both children and adults and a major concern because of its health consequences. Obesity has been linked to an array of health disorders, such as type 2 diabetes, cardiovascular disease, and disability. In 1995, WHO estimated that there were approximately 200...

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...

Evidence for a Role in Alzheimers Disease

Alzheimer's disease (AD) is a progressive, often insidious, dementing disease occurring in mid- to late life. Its incidence increases with age, such that at age 85+ approximately 20 of people suffer from the condition. AD causes neurone death and a reduction in brain volume. The progression of the disease (which in most cases means approximately 7 years of intellectual and personal decline until death) cannot be arrested and eventually patients become bedridden. At this stage, concomitant...

Fatty Acid Unsaturation and the Essential Fatty Acids

Monounsaturated and polyunsaturated fatty acids are extraordinarily important in human health and nutrition. Thus, the insertion of double bonds into the carbon skeleton of a fatty acid is a vital metabolic function. However, humans are in general not capable of inserting double bonds closer than nine carbon atoms from the methyl end of a fatty acid. Thus, we are incapable of the de novo synthesis of two important classes of fatty acids, the n-3 fatty acids such as docosahexaenoic acid (22...

Etiology of Gum Disease

Gum disease arises as a result of bacterial infection of the gums, especially at the tooth margins. It is often assumed that excessive accumulation of plaque, arising from inappropriate dietary habits, is a factor in this condition, but there is little evidence for any material influence of diet. The milder forms of gum disease are extremely common in all populations. More severe disease is the most frequent cause of tooth loss in older people. The best form of protection from gum disease is...

Exercise and Physical Activity

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

Extrahepatic Regulation

A key factor in the regulation of ketogenesis is the availability of nonesterified long-chain fatty acids to the liver, which in turn is controlled by their release from adipose tissue. The enzyme responsible for the initiation of the hydrolysis of stored triacylglycerols to fatty acids is hormone-sensitive lipase. As its name implies, this enzyme is exquisitely sensitive to hormones adrenaline (in the plasma) and noradrenaline (released from sympathetic nerve endings) are activators, whereas...

Example

The global increase in the prevalence of childhood overweight and obesity and their associations with disease during childhood and adulthood is now alarming public health officials. One approach to understanding the pathways between overweight obesity and disease is identifying the factors that cause excess weight gain. The time in utero is considered a critical period. During the growth and development years, the periods known as 'adiposity rebound' and adolescence are considered critical...

Excessive Alcohol Consumption during Pregnancy

Chronic alcohol abuse may result in a wide spectrum of secondary disturbances of the absorption and utilisation of many nutrients, including glucose, amino acids, fat, sodium, and some vitamins (especially thia-min, vitamin B12, and folate). The inhibition of folate absorption by alcohol is of particular concern because of the risk of neural tube defects associated with an inadequate supply of this vitamin to the fetus before conception and during the first trimester of pregnancy. Alcohol may...

Extra Energy Costs

The cost of growth amounts to 10-25 kJ g of new tissue deposited the value is higher if fat with little lean tissue is laid down. A newborn has a high energy requirement of approximately 460 kJ kg, with a cost of weight gain amounting to 26kJ g however, by 1 year of age the total daily requirement decreases to approximately 335 kJ kg as growth slows, with growth now costing 10kJ g. Breast-fed infants have an energy requirement approximately 10 lower than that of bottle-fed infants (Table 4)....

Fatty Liver

The triacylglycerol (TG) produced by the liver is mainly delivered to other tissues as very low-density Table 1 Recommended adequate intakes (AI) for choline Table 1 Recommended adequate intakes (AI) for choline From Institute of Medicine, National Academy of Sciences USA (1998) Dietary reference intakes for folate, thiamin, riboflavin, niacin, vitamin B12, panthothenic acid, biotin, and choline, vol. 1. Washington DC National Academy Press. From Institute of Medicine, National Academy of...

Experimental Animal Data

Guinea Pig Model of Pulmonary Tuberculosis In the past 30 years, a modest literature has accumulated regarding the link between diet, antimyco-bacterial immunity, and disease resistance in TB. The vast majority of this work has been conducted in a highly relevant guinea pig model of low-dose pulmonary TB. The pathogenesis of TB in this model mimics essentially all of the important aspects of TB in humans. Early studies established that moderate, chronic deficiencies of protein and other...

Experimental Thiamin Deficiency in Man and Measurement of Thiamin Status

In young and healthy nonalcoholic subjects, subjective symptoms appear after 2 or 3 weeks of deficient diet but urinary thiamin will already be falling (Table 3). Characteristic early symptoms include anorexia, weakness, dysthesiae, and depression. At this stage, urinary thiamin will be almost zero, ETKL activity depressed, and the TDP effect approximately 15-30 . After 6-8 weeks the only objective signs at rest may be a slight fall in blood pressure and moderate weight loss, although urinary...

Fat Free Mass and Energy Needs

One of the truly age-driven phenomena is the loss of muscle mass and strength, called sarcopenia. It is distinct from muscle loss (cachexia) caused by inflammatory disease or from weight loss and attendant muscle wasting caused by starvation or advanced disease. Regardless of major differences between individuals, aging-related changes in body composition with time are universal. In addition to changes in lean tissue, this also holds for changes in fat mass, body water, and bone mass....

Fermentable Carbohydrate

Acidogenic bacteria metabolize (ferment) simple sugars (glucose, fructose, sucrose, lactose, and maltose) to acids. Sugars may be present as a result of their direct consumption or as a result of the enzymatic breakdown of starches within the mouth by salivary amylase. Thus, a substantial proportion of a typical diet will contain a source of fermentable carbohydrate, and many, if not all, eating and drinking occasions will give these bacteria one of these metabolic precursors. The more...

Fructose and Glucose Metabolism

With fructose ingestion, there is an increased flux through the glycolytic pathway, with formation of pyruvate and lactate. As fructose-1-phosphate is formed, at the initial priming stage of glycolysis, it feeds forward and enhances the activation of pyru-vate kinase (EC 2.7.1.40), thereby facilitating the passage of fructose carbon to pyruvate and lactate. With fructose ingestion, it is common to observe increases in blood lactate concentrations. In the postprandial state, fructose serves to...

Flora Nutrient Interactions

There is a complex interaction between food and microflora in a feedback-like system. Different types of diets can lead to changes in fecal flora, and its resultant metabolic activity can be altered. When individuals consuming a vegetarian diet were compared to those on a typical Western diet, the latter had microflora that showed greater hydrolyz-ing ability leading to a more effective metabolism of bile acids and subsequently reduced cholesterol. Similar studies in mice have shown differences...

Food Sources of Folate

Folate is synthesized by microorganisms and higher plants but not by mammals, for which it is an essential vitamin. The most concentrated food folate sources include liver, yeast extract, green leafy vegetables, legumes, certain fruits, and fortified breakfast cereals. Folate content is likely to depend on the maturity and variety of particular sources. Foods that contain a high concentration of folate are not necessarily those that contribute most to the overall intakes of the vitamin in a...

Folic Acid and Vitamin B12

There is a substantial increase in folate requirements during pregnancy, from 400 mg Dietary Folate Equivalents in the nonpregnant state to 600 mg per day, because of increased erythropoiesis and fetal-placental growth. Increased folate intakes throughout childbearing age are recommended to prevent neural tube defects such as spina bifida and anen-cephaly, the most common birth defects, and to lower the risk of abruptio placenta. To be effective for preventing neural tube defects in women at...

Fructose and Lipid Metabolism

When large amounts of fructose are ingested, the glycolytic pathway becomes saturated with intermediates. In these circumstances, the intermediates become substrates for triacylglycerol synthesis DHAP can be converted to glycerol, and acetyl-CoA can enter the lipogenic pathway to form fatty acids that are then esterified to the glycerol molecule to form triacylglycerols. During the initial step of lipogenesis, malonyl-CoA is formed. This intermediate serves to inhibit the transport of fatty...

Functional Roles of Sucrose in Foods

Refined sucrose is added to foods for more than just its sweetness. The difficulties inherent in producing low-joule products using intense sweeteners attest to this. For example, sucrose contributes to the bulk and texture of cakes and cookies and it provides viscosity and mouth feel in liquids such as soft drinks and fruit juices. Sucrose is also a powerful preservative and contributes the long storage life of jams and confectionery. In frozen products like ice cream, sucrose has multiple...