Population Groups at Risk of Vitamin K Deficiency

Because of the minimal extent of transfer of vitamin K across the placenta, the fetus and newborn infant have much lower circulating vitamin K than adults (typically 30-fold lower). In addition, human milk has a lower concentration of the vitamin than that of most other mammalian species. Although low vitamin K levels have not been found to affect the developing fetus in a functionally deleterious way, it is clear that the newborn, and especially the solely breast-fed infant, is at higher risk...

The Paradox of Rapid Population Growth in Undernourished Populations

In many historical populations with slow population growth, poor couples living together to the end of their reproductive lives had only 6 or 7 living births. Most poor couples in many developing countries today also have 6 or 7 living births during their reproductive life span. This total fertility rate is far below the human maximum of 11 or 12 children observed among well-nourished couples not using contraception, such as the Hutterites. However, 6 children per couple today in developing...

Neuroendocrine Effects of Alcohol

Alcohol activates the sympathetic nervous system, increasing circulating catecholamines from the adrenal medulla. Hypothalamic-pituitary stimulation results in increased circulating cortisol from the adrenal cortex and can, rarely, cause a pseudo-Cushing's syndrome with typical moon-shaped face, truncal obesity, and muscle weakness. Alcoholics with pseudo-Cushing's show many of the biochemical features of Cushing's syndrome, including failure to suppress cortisol with a 48-h low-dose...

Cobalamin Vitamin B12

Few vitamins have been more challenging to structure-function studies than vitamin B12. Among its many unique features, B12 is the only vitamin- HO OH Acetyl-coenzyme A Figure 6 Pantothenic acid in the structure of coenzyme A. coenzyme known to have a transition metal ion (cobalt) coordinated to its structure. The metal allows some usual chemistry (see 00058). The vitamin is present in a variety of foods but is almost totally lacking in plants. Although the vitamin can be synthesized de novo by...

Mucus

The mucus covering the surface of the stomach consists of a mixture of many secretions and exfoliated cells. The major viscous and gel-forming component of the mucus gel is mucin, present at approximately 40mgml-1 in the firm layer and approximately 15mgml-1 in the sloppy layer. Mucin is also present in gastric juice resulting from pepsin erosion of the surface of the gel. It is secreted by the surface epithelial cells and mucous neck cells and is a glycoprotein, about 80 carbohydrate. The core...

Cell Kinetics of the Enterocyte

The life span and kinetics of small intestinal enter-ocytes are particularly important in understanding the process of absorption. Enterocytes have a Submucosal artery and vein Submucosal plexus Figure 1 Wall of the small intestine. The intestinal surface area is enhanced by finger-like villi. Submucosal artery and vein Submucosal plexus Figure 1 Wall of the small intestine. The intestinal surface area is enhanced by finger-like villi. particularly short life and the epithelium of the small...

Helminth Parasites

Ascaris lumbricoides (roundworm) About 73 of all infections by this worm are estimated to occur in Asia with many countries having prevalence rates greater than 50 . In some rural areas over 90 Table 2 Parasite interference with host nutrition Table 2 Parasite interference with host nutrition Reduced fat and nitrogen uptake Reduced vitamin A status Loss of trace elements, e.g., zinc Growth retardation, weight loss Reduced fat absorption Reduced vitamin A status Lowered disaccharidase activity...

Alcoholic Liver Disease

Alcoholic liver disease is among the top ten causes of mortality in the US with somewhat higher mortality rates in western European countries where wine is considered a dietary staple, and is a leading cause of death in Russia. Among the three stages of alcoholic liver disease, fatty liver is related to the acute effects of alcohol on hepatic lipid metabolism and is completely reversible. By contrast, alcoholic hepatitis usually occurs after a decade or more of chronic drinking, is associated...

Intrauterine Growth Restriction IUGR

In developed countries, 3-7 of newborns are classified as IUGR. These infants weigh less than two standard deviations below the mean of a population born at the same gestational age. Most of these infants experienced suboptimal nutrient supply, and consequently a restriction of fetal growth, as a result of some form of placental insufficiency. IUGR imposes increased risks of specific types of fetal and neonatal morbidity and mortality (Table 5). Table 5 Risks of specific types of fetal and...

Metabolism in Different Organs

The liver is responsible for most of the deamination of amino acids, except for the branched-chain amino acids, which are transaminated in muscle. Oxidation of amino acids is one of the main sources of energy for the liver. The liver is also the main site of gluco-neogenesis, extracting large amounts of glutamine and alanine from the plasma for this purpose. The liver is the only site of urea synthesis. Skeletal and cardiac muscle and adipose tissue are the main sites for transamination of the...

Regulators of Lipolysis and Fat Storage

The processes of lipolysis and fat storage are regulated by hormonal factors, which either enhance or suppress the activities of HSL and LPL. Through the action of glucocorticoid receptors, glucocorticoids enhance LPL activity and promote abdominal deposition of fat. The density of glucocorticoid receptors is greater in the visceral abdominal depot than in the subcutaneous abdominal depot. Therefore, an increase in glucocorticoid secretion is associated with increases in abdominal fat...

Nutrition Policies In Developing And Developed Countries

IC Geissler, Kings College London, London, UK 2005 Elsevier Ltd. All rights reserved. This article reviews the definition of nutrition policy and aspects specific to developing and developed countries components of typical policies government structures for their formulation and implementation the types of programs used to implement policy historical trends of emphasis the international promotion of nutrition policies constraints imposed by major development organisations the effectiveness and...

Metabolism and Excretion

Knowledge about chemical changes that must occur before excretion for most of the ultratrace elements is quite limited. Perhaps the best characterized is inorganic arsenic, which is methylated into monomethylarsonic acid and dimethylarsinic acid, and organic arsenic, which is converted into, or remains mostly as, arsenobetaine before being excreted in the urine. Other ultratrace elements that are known to be incorporated into biochemical metabolites for transport and or excretion include...

Absorption Metabolism and Excretion of Vitamin D

Vitamin D (vitamin D without a subscript represents either vitamin D2 or D3) is fat soluble and, therefore, once ingested vitamin D2 and vitamin D3 are incorporated into the chylomicron fraction and absorbed in the small intestine into the lymphatic system. Both dietary vitamin D2 and vitamin D3, and cutaneous vitamin D3 enter the circulation and are bound to a specific a1-globulin known as the vitamin D-binding protein. It is believed that this protein acts as a buffering system whereby it...

Zinc Deficiency

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

Choline in Foods

Choline, choline esters, and betaine can be found in significant amounts in many foods consumed by humans (see Figure 1 and Figure 2) some of the choline and betaine is added during processing (especially in the preparation of infant formula). Figure 1 Total choline content of some common foods. Foods, which had been prepared as normally eaten, were analyzed for choline, phosphocholine, glycerophosphocholine, phosphatidyl-choline, and sphingomyelin content using an HPLC mass spectrometry...

Causes of Famine

Starvation is a matter of some people not having enough food to eat, and not a matter of there being not enough food to eat. Large numbers of people starve during famine, which is usually followed by epidemics of lethal infectious diseases. Typically, a plethora of forces or conditions act within society to deprive people of food to survive. General food decline in a population may be an important factor, but it is neither necessary nor sufficient as a cause, as amply revealed by critical...

Food Sources Absorption Distribution and Turnover

Food sources of phylloquinone for man (Table 1) include green leafy vegetables as the major Figure 1 Chemical structures of phylloquinone, menaquinones, menadione, warfarin, and dicumarol. quantitative source however, its availability for absorption from these foods is thought to be relatively poor. Certain plant-derived oils, notably soya and canola oils, are also rich in the vitamin, which is probably much more readily available from such sources than it is from leaves. Menaquinones are...

Fatty Acids and Acylglycerols Nomenclature

Fatty acids are hydrocarbons of chain length two or greater with a carboxyl group at one end. Hydrocarbon chains are termed acyl lipids, and fatty acids occur most abundantly esterified to glycerol as tria-cylglycerols (Figure 1). Nomenclature for fatty acids has evolved from studies of food or organ sources of Figure 1 Stereochemical numbering of lipids derived from glycerol. R1, R2, and R3 refer to sn nomenclature. Table 1 Fatty acids important in nutrition 2 0 3 0 4 0 6 0 8 0 10 0 12 0 14 0...

Glucose Space

The glucose space (i.e., the extracellular water volume) is constant in any individual and Glucose precursors j j Glycogen Figure 1 Schematic representation of blood glucose concentration and its relationship to the body glucose pool. The central system represents the hypothetical glucose pool, the actual size of which is represented by the horizontal axis (i.e., volume of distribution multiplied by blood (and extracellular fluid) glucose concentration). The postulated homeostatic switch is the...

Pregnancy Weight Gain Recommendations

In 1970, the US National Academy of Sciences published guidelines for weight gain during pregnancy in the report, Maternal Nutrition and the Course of Pregnancy. The recommended pregnancy gain was 24 lb (10.9 kg), with a range of 10-25 lb (9.1-11.4 kg). The report advised health care providers and pregnant women not to restrict weight gain a practice that had been fairly widespread during the previous decade in order to reduce the perceived risks of labor complications, preeclampsia, and excess...

Effectiveness of Food Fortification as a Public Health Intervention

The benefits, at a national level, of historical fortification efforts are generally not well documented however, epidemiological evaluations of pilot-scale programs are considered to have played an important role in the widespread implementation of these programs. Iodization of salt was found to decrease the incidence of goiter by 74-90 in different counties in the State of Michigan in the US in the first 10 years of the program (1924-35). Salt iodization is credited with the elimination of...

Metabolic Functions

In mammals, biotin serves as an essential cofactor for five carboxylases, each of which catalyses a critical step in intermediary metabolism. All five of the mammalian carboxylases catalyze the incorporation of bicarbonate as a carboxyl group into a substrate and employ a similar catalytic mechanism. Biotin is attached to the apocarboxylase by a condensation reaction catalyzed by holocarboxylase synthetase (Figure 1). An amide bond is formed Figure 1 Biotin metabolism and degradation. Ovals...

Salt Intake and Blood Pressure

When salt is ingested it is readily absorbed in the small intestine in association with other molecules such as glucose. The intestinal secretions also contain sodium at concentrations similar to those found in the plasma but the colon has a highly effective active transport system for absorbing practically all the sodium in the colonic contents only about 1 mmol of sodium is normally excreted in the feces except in cases of severe diarrhea Once the sodium is absorbed the body ensures that the...

Vitamin A Deficiency Disorders

Vitamin A is essential for maintaining normal retinal function and differentiation of rapidly dividing, bipotential cells. These regulatory roles give rise to specific manifestations of hypovitaminosis A, such as poor photoreceptor function leading to night blindness, metaplasia, and keratinization of mucosal epithelial surfaces leading to clinical abnormalities of conjunctival and corneal xerosis as well as epidermoid metaplasia and other epithelial defects throughout the respiratory,...

General Nutritional Management of Malabsorption

As with all nutritional disorders, a thorough nutritional assessment is needed to plan rational therapy of malabsorption. Important historical points to review include duration of symptoms, underlying etiology of malabsorption, ability to meet nutritional needs by mouth, the presence of food allergies, and concurrent medical and surgical problems. The patient's nutritional status (weight, height, body mass index, and their respective percentiles) should be determined. Tests of body composition...

Properties and Sources of Fructose

Fructose has a fruity taste that is rated sweeter than sucrose. Sweetness ratings of fructose are between 130 and 180 (in part dependent on the serving temperature) compared to the standard, sucrose, rated at 100 . Both sucrose and fructose are used extensively Needleman HL, Schell A, Bellinger D et al. (1990) The long-term effects of exposure to low doses of lead in childhood. An 11-year follow-up report. New England Journal of Medicine 322 83-88. Report of the International Committee on...

Indirect Calorimetry

A Raman and D A Schoeller, University of Wisconsin-Madison, Madison, WI, USA 2005 Elsevier Ltd. All rights reserved. All living organisms require a source of energy for survival. Among animals, this energy is provided in the form of chemical energy in the nutrients they consume, which are converted to other forms of energy through respiration. This conversion is subject to the same laws of thermodynamics that govern all energy systems. The first law of thermodynamics states that energy can...

Effects of Dietary ALA Compared with Long Chain n3 Fatty Acid Derivatives on Physiologic Indexes

Several clinical and epidemiologic studies have been conducted to determine the effects of long-chain n-3 PUFAs on various physiologic indexes. Whereas the earlier studies were conducted with large doses of fish or fish oil concentrates, more recent studies have used lower doses. ALA, the precursor of n-3 fatty acids, can be converted to long-chain n-3 PUFAs and can therefore be substituted for fish oils. The minimum intake of long-chain n-3 PUFAs needed for beneficial effects depends on the...

Physiological Ketosis

Physiological hyperketonemia is found in the suckling neonate (high-fat diet of the milk Figure 1), postexercise (depletion of hepatic glycogen reserves), and after prolonged fasting (more than 24 h Figure 7). All these situations have in common a low hepatic carbohydrate status (depletion of glycogen and or activation of gluconeogenesis) and therefore from a physiological standpoint one would expect an increased rate of ketogenesis. Comparison of the factors which can influence ketogenesis in...

Dietary Sources

Carotenoids cannot be synthesized by humans therefore they must be obtained from dietary sources. These are primarily highly pigmented red, orange, and yellow fruits and vegetables. The caro-tenoid lycopene is red however, not all red fruits and vegetables contain lycopene. For example, the red in strawberries, apples, and cherries is a result of their anthocyanin content whereas, tomatoes, watermelon, and pink grapefruit derive their red color from lycopene. The carotenoids -carotene,...

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 7.0 mmol l or the 2-h value exceeds 11.1...

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...

Practical Management of Eating Difficulties

Anorexia (loss of appetite) is often associated with other eating difficulties, such as nausea, taste changes, and constipation, and addressing these problems may improve the patient's appetite. Pain may also contribute to anorexia, and regular analgesia for pain may in turn help improve appetite, as may dietary alterations (Table 2). For patients who have severe anorexia, an appetite stimulant should be considered, such as dexamethasone, medroxyproes-terone acetate, or megestrol acetate....

Pathophysiology and Symptoms

Malabsorption can occur when any of the several steps in nutrient digestion, absorption, and or assimilation are interrupted see Table 1 for a list of congenital defects in nutrient assimilation. Carbohydrate malabsorption can occur, for instance, when intestinal disaccharidases are reduced in concentration at the enterocyte. The brush border membrane produces four disaccharidases that are important in carbohydrate digestion. These enzymes are sucrase-isomaltase, maltase-glucoamylase,...

Dynamics of Energy Balance with Overfeeding and Underfeeding Figure

To understand the dynamic aspect of energy balance while overfeeding is of the utmost important, since as mentioned previously the system is not invariant. Decreased En relative to E requirement Figure 9 Dynamic change in energy balance following a step steady increase (A) overfeeding (or decrease) (B) underfeeding in energy intake. The time required to reach a new equilibrium in energy balance is very long (years) and depends upon the initial energy imbalance, the magnitude of adaptation of...

Energy Imbalance and Body Weight

Positive energy balance leads to body weight gain and negative energy leads to body weight loss. There is no fixed relationship between these two variables so that relatively small energy retention can be accompanied by large body weight gain and vice versa. The confounding factor is the associated water storage. Long-term fluctuations in fat stores will be reflected in body weight. There is a difference in the energy value of fat mass and fat-free mass, the latter including the glycogen-water...

Macronutrient Balance Energy Balance and Storage

Since macronutrients (carbohydrate, fat, protein, and alcohol) are the sources of energy, it is logical to consider energy balance and macronutrient balance together as the opposite side of the same coin. There is a direct relationship between energy balance and macronutrient balance, and the sum of individual substrate balance (expressed as energy) must be equivalent to the overall energy balance. Thus exogenous carbohydrate carbohydrate oxidation exogenous protein protein oxidation lipid...

Body Composition Applications During Aging

During the adult life span, body weight generally increases slowly and progressively until about the seventh decade of life, and thereafter, declines into old age. An increased incidence of physical disabilities and comorbidities is likely linked to aging-associated body composition changes. Characterization of the aging processes has identified losses in muscle mass, force, and strength, which collectively are defined as 'sarcopenia.' Little is known about the overall rate at which sarcopenia...

Unilocular And Multilocular Lipids Drops Synonym

Acids see Electrolytes Acid-Base Balance G Fr hbeck and J Gomez-Ambrosi, Universidad de 2005 Elsevier Ltd. All rights reserved. The role of white adipose tissue (WAT) in storing and releasing lipids for oxidation by skeletal muscle and other tissues became so firmly established decades ago that a persistent lack of interest hindered the study of the extraordinarily dynamic behavior of adipocytes. However, disentangling the neuroendocrine systems that regulate energy homeostasis and adiposity...

Postoperative Dysphagia

Oropharyngeal dysphagia can occur in the postoperative setting for a number of reasons. Procedures involving the upper aerodigestive tract for either benign or malignant disease can result in varying degrees of dysphagia with or without aspiration due to alteration in the anatomical mechanism of swallowing. In addition, procedures in the neck can be complicated by inadvertent injury to the aerodigestive tract or to the nerves innervating the muscles of deglutition, resulting in dysphagia. The...

Genetics

Family studies and research in twins indicate that about 50 of the variation of serum cholesterol concentrations in the general population can be explained by genetic polymorphisms. Presumably this variation is related to factors that regulate lipo-protein concentrations. In some cases, specific genetic defects are severe, resulting in marked changes in lipoprotein concentrations. When this occurs, the affected individual is said to have a mono-genic disorder. In other cases, multiple genetic...

Antiinflammatory Aspects of n3 Fatty Acids

Many experimental studies have provided evidence that incorporation of alternative fatty acids into tissues may modify inflammatory and immune reactions and that n-3 fatty acids in particular are potent therapeutic agents for inflammatory diseases. Supplementing the diet with n-3 fatty acids (3.2 g EPA and 2.2 g DHA) in normal subjects increased the EPA content in neutrophils and mono-cytes more than sevenfold without changing the quantities of AA and DHA. The anti-inflammatory effects of fish...

Prevention of Dehydration

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

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...

The Fetus

Iodine deficiency of the fetus is the result of iodine deficiency in the mother (Figure 2). The condition is Table 1 Spectrum of Iodine Deficiency Disorders Mental deficiency, deaf mutism, spastic Retarded mental and physical development Retarded mental and physical development Increased susceptibility to nuclear radiation Reproduced with permission from Oxford University Press and the World Health Organization, WHO UNICEF ICCIDD (2001). Reproduced with permission from Oxford University Press...

Hunger Physiological Determinants

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

Complex Causation

Although pellagra in dogs and humans usually responds well to supplements of pure niacin, there are several further strands to the story that complicate the idea that all the characteristics and manifestations of pellagra can be explained as the result of a simple dietary deficiency of a single water-soluble factor (i.e., vitamin) identified as the molecule niacin. First, it soon became clear that the total niacin content of different foods, as measured by chemical analysis, was not necessarily...

PMS and Dietary Factors

Various reports, many of a preliminary nature, or based on clinical experience, suggest that women suffering from PMS consume more sugar, refined carbohydrate, and dairy products and less fiber, B complex vitamins, iron, zinc, and magnesium than normal women. Carbohydrate-rich meals have been shown to improve mood in women with premenstrual depression. The reason for this has been indicated in animal studies The availability of tryptophan to the brain increases following such meals. As...

Anthropometric Techniques

Anthropometric indices used to measure fat patterning include skinfold thicknesses, circumferences, sagittal diameter, and ratios such as Figure 2 Cross-sectional images of the abdomen obtained by MRI. (A) Small subcutaneous fat area and enlarged visceral fat area. (B) Small visceral fat area in comparison with subcutaneous fat depot. Figure 2 Cross-sectional images of the abdomen obtained by MRI. (A) Small subcutaneous fat area and enlarged visceral fat area. (B) Small visceral fat area in...

Muscle Tone and Positioning

It is important to understand the influences of muscle tone and proper positioning on the ability to eat safely and efficiently in this population. Increased or decreased muscle tone contributes to difficulty preserving a patent airway, compromised self-feeding skills, poor rib cage expansion and esophageal motility, and difficulty in maintaining a stable supported base for seating. Fluctuating muscle tone leads to involuntary movements and limited postural stability. Despite the type of muscle...

Body Mass Index BMI

The body mass index (BMI weight kg height m2) continues to be the most commonly used index of weight status, where normal weight is a BMI 18.5-25.9 kg m2 overweight is a BMI 25.0-29.9 kg m2 and obese a BMI > 30.0 kg m2. BMI is a commonly used index of fatness due to the high correlation between BMI and percent body fat in children and adults. The prediction of percent body is dependent on age (higher in older persons), sex (higher in males), and race (higher in Asian compared to African...

Complementary Feeding

K G Dewey, University of California Davis, Davis, CA, USA 2005 Elsevier Ltd. All rights reserved. Complementary feeding has been defined as .the process starting when breast milk alone is no longer sufficient to meet the nutritional requirements of infants, and therefore other foods and liquids are needed, along with breast milk. In the past, such foods were often called 'weaning foods.' However, the term 'complementary foods' is preferred because weaning implies the cessation of breastfeeding,...

Insulin Resistance and Hyperinsulinemia

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

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....

Effects on the Cardiovascular System

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

Low Carbohydrate Diets

The recent trend of weight loss diets promotes some level of carbohydrate restriction and increased protein consumption. Some examples are Dr Atkins New Diet Revolution, The South Beach Diet, and The Carbohydrate Addict's Diet. This dietary advice is contrary to that proposed by governmental agencies (US Department of Agriculture Department of Health Services, National Institutes of Health) and nongovernmental organizations (American Dietetic Association, American Heart Association, American...

Dietary Cholesterol and Plasma Cholesterol

The effect of dietary cholesterol on plasma cholesterol levels has been an area of considerable debate. In 1972, the American Heart Association recommended that dietary cholesterol intake should average less than 300mgperday as part of a 'heart-healthy,' plasma cholesterol-lowering diet. Since that initial recommendation, a number of other public health dietary recommendations in the United States have endorsed the 300 mg daily limit. Interestingly, few dietary recommendations from other...

Dietary Cholesterol Intake Patterns

Dietary cholesterol intakes in the United States have been declining, from an average of 500 mg per day in men and 320 mg per day in women in 1972 to levels in 1990 of 360 mg per day in men and 240 mg per day in women. This decline is due in part to dietary recommendations to the US public to reduce total and saturated fat intake and to reduce dietary cholesterol daily intake to less than 300 mg and in part from the increased availability of products with reduced fat and cholesterol content....

Type II or Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant disorder characterized by elevation of plasma LDL cholesterol levels. Mutations at the LDL receptor gene locus on chromosome 19 are Table 4 Classification of hyperlipidemias according to Fredrickson Type Plasma cholesterol Genetic disorder triacylglycerol fraction(s) affected risk Normal to elevated Very elevated Chylomicrons Normal or elevated Elevated Normal or elevated Very elevated Apo C-II deficiency High Familial...

Dietary Cholesterol

All dietary cholesterol is derived from animal products. The major sources of cholesterol in the diet are egg yolks, products containing milk fat, animal fats, and animal meats. Many studies have shown that high intakes of cholesterol will increase the serum cholesterol concentration. Most of this increase occurs in the LDL cholesterol fraction. When cholesterol is ingested, it is incorporated into chylomicrons and makes its way to the liver with chylomicron remnants. There it raises hepatic...

Age and Risk Factor Profile

A few studies have indicated that subjects already at high risk of coronary disease experience a greater beneficial effect of drinking alcohol moderately conversely, only in those with a high risk level is coronary heart disease prevented. Hence, the large Nurses Health Study found that the J-shaped relation was significant only in women older than 50 years of age, whereas younger women who had a light alcohol intake did not differ from abstainers with regard to mortality. Fuchs et al. found...

The Observational View of Dietary Antioxidants

Cancer and cardiovascular disease (CVD) are the two leading causes of death worldwide, diabetes mellitus is reaching epidemic proportions, and dementia and maculopathy are largely untreatable irreversible disorders that are increasingly common in our aging population. The prevalence and standardized mortality rates of these diseases vary considerably between and within populations. Mortality from CVD varies more than 10-fold amongst different populations, and incidences of specific cancers vary...

Health Effects of Carbohydrates

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

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...

Tissue Uptake and Storage

The body pool of cholesterol is approximately 145 g, with one-third of this mass localized in the central nervous system. The remainder of the metabolically active cholesterol pool exists in the plasma compartment (7.5-9 g) and as constituents of body tissues. In humans, tissue cholesterol levels are relatively low, averaging 2 or 3 mg g wet weight. Little information exists regarding changes in hepatic and extrahepatic tissue cholesterol concentrations with changes in dietary cholesterol...

Regulation of Synthesis

The rate-limiting enzyme in cholesterol biosynthesis is 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a microsomal enzyme that converts HMG-CoA to mevalonic acid in the polyisoprenoid synthetic pathway. Peripheral tissue cholesterol synthesis is much less responsive to regulatory factors compared to the liver, which is controlled by a variety of dietary, hormonal, and physiological variables. Studies indicate that endogenous cholesterol synthesis is significantly increased in...

Major Dietary Sources

The major sources of cholesterol in the diet are eggs, meat, and dairy products. A large egg contains approximately 215 mg of cholesterol and contributes approximately 30-35 of the total dietary cholesterol intake in the United States. Meat, poultry, and fish contribute 45-50 , dairy products 12-15 , and fats and oils 4-6 . In the United States, the range of dietary cholesterol intake is 300-400 mg per day for men and 200-250 mg per day for women thus, for much of the population the national...

Potential Mechanisms Indicating a Role in the Etiology of Coronary Heart Disease

The mechanism for risk reduction and the fiber components responsible need resolution. Elevated plasma total and low-density lipoprotein (LDL) cholesterol concentrations are established risk factors for coronary morbidity and mortality. There are abundant human and animal data showing that diets high in soluble fiber lower plasma cholesterol. One population study has shown a significant negative relationship between viscous (soluble) fiber intake and carotid artery atherogensis as measured by...

Ldl Hdl and atherosclerosis

Membrane function is compromised if it contains either too much or too little cholesterol. Epidemio-logical studies have classified raised plasma cholesterol levels as a risk factor for atherosclerosis, and it is one of the more important predictors of coronary heart disease (CHD). Elevated plasma cholesterol concentration (hypercholesterolemia) is associated with an increased concentration of LDL, owing to either an increased rate of LDL formation or a decrease in the rate at which they are...

Endothelial dysfunction

Decrease in the production, release, or action of NO may lead to enhanced expression of adhesion molecules and chemotactic factors at the endothelial surface. The exact nature of endothelial dysfunction is unknown, although possibilities include a decreased expression of NO synthase, imbalance between the production of endothelium-derived constricting and relaxing factors, production of an endogenous NO synthase inhibitor, and overproduction of oxygen-derived free radicals including O2. The...

Eicosanoid Metabolism and Biological Effects of n6 and n3 Fatty Acids

When humans ingest fish or fish oil, the ingested EPA and DHA partially replace the n-6 fatty acids (especially AA) in cell membranes, particularly those of platelets, erythrocytes, neutrophils, monocytes, and liver cells. Because of the increased amounts of n-6 fatty acids in the Western diet, the eicosanoid metabolic products from AA, specifically prostaglandins, thromboxanes, leukotrienes, hydroxy fatty acids, and lipoxins, are formed in larger quantities than those formed from n-3 fatty...

Total Saturated Fat Content of Diets

Using statistical techniques, results from independent experiments have been combined to develop equations that estimate the mean change in serum lipoprotein levels for a group of subjects when carbohydrates are replaced by an isoenergetic amount of a mixture of saturated fatty acids. The predicted changes for total LDL and HDL cholesterol and triacylglycerols are shown in Figure 1. Each bar represents the predicted change in the concentration of that particular lipid or lipoprotein when a...

Effect of trans Fatty Acids on Plasma Lipoproteins

Raised plasma concentrations of low-density lipopro-tein (LDL) are considered to be a risk factor for coronary heart disease (CHD) in contrast, reduced concentrations of high-density lipoprotein (HDL) are considered to increase risk. It therefore follows that to help protect against CHD, diets should ideally help to maintain plasma concentrations of HDL cholesterol and to lower those of LDL cholesterol. Dietary factors that raise LDL and lower HDL concentrations would be considered to be...

Guide for Separating Food Folklore Facts from Fiction in Clinical Situations and A Practical Example

For summarizing and evaluating food folklore involving diet-health relationships, health professionals need to not only evaluate the evidence but also use their clinical judgment and communications skills to relate this to clients or patients. How can food folklore be evaluated in discussions with laypeople and in counselling situations The strategies are similar to those employed in research and in more formal evidence-based reviews, but contextual realities require tailoring of the approach....

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...

Pathophysiology of Stone Formation

There are three kinds of gall stone cholesterol, black pigment, or brown pigment stones. Cholesterol stones constitute 75-90 of all gall stones. They are composed purely of cholesterol or have cholesterol as the major chemical constituent. Most cholesterol gall stones are of mixed composition. Pigmented stones get their color and their name from precipitated bilirubin. Increased production of unconjugated bilirubin causes black pigmentation. Formation of black pigment stones is typically...

Benefits of Low Glycemic Index Carbohydrates on Cardiovascular Disease Risk Factors

High glycemic index foods induce postprandial hyperinsulinemia, which is a powerful predictor for metabolic risk factors and CVD in epidemiological studies. Both cross-sectional and prospective population studies have shown favorable lipid profiles in association with high carbohydrate diets. Initially, these benefits were attributed to a high fiber content. However, when the glycemic index is controlled for, it is the low glycemic index diets rather than high fiber content that have the...

Contemporary Low Calorie Carbohydrate Restricted Diet

In view of the well-recognized link between insulin resistance syndrome, hyperuricemia, and gout, a diet emphasizing reduced calorie intake with moderate restriction of carbohydrates and liberalization of protein and unsaturated fat consumption has been espoused for patients with gout. Low-purine foods are often high in both carbohydrate and saturated fats these foods tend to further decrease insulin sensitivity, thereby contributing to even higher levels of insulin, glucose, triglycerides, and...

Homocysteine and Vascular Disease

The current interest in homocysteine is primarily related to its recognized status as an independent risk factor for cardiovascular, cerebrovascular, and peripheral vascular disease. This homocysteine theory of vascular disease comes directly from a seminal observation made by Kilmer McCully. In the early to mid-1960s, it was recognized that a prominent characteristic of patients with homocystinuria caused by defects in cystathionine -synthase were very high elevations of both homocysteine and...

Other Dietary Approaches for the Prevention and Management of CVD

Very Low-Fat High-Carbohydrate Diet and High-Protein Low-Carbohydrate Diet When considering diets very low in fat and high in carbohydrates ('very low-fat' diets), it is important to separate the effects of the composition of the diet from confounding factors associated with intentional weight loss. For the purposes of this discussion, a very low-fat diet will be defined as less than 15 of energy as fat. Consumption of a very low-fat diet without a decrease in energy intake frequently decreases...

Dietary Factors with Limited or Uncertain Effect on Blood Pressure

Evidence from observational studies and several clinical trials suggests that increased fiber intake may reduce blood pressure. A meta-analysis documented that supplemental fiber (average increase of 14g day) was associated with net systo-lic diastolic reductions of 1.6 2.0 mmHg, respectively. Still, high-quality epidemiologic studies and clinical trials are needed before one can recommend increased fiber intake as a means to lower blood pressure. Evidence that increased calcium intake might...

Adipose Tissue Hormones

The adipose tissue secretes different hormones called adipocytokines. Their secretion seems to vary in relation to the amount of adipose tissue accumulated, although the exact mechanism is not known. During profound weight loss, as in anorexia nervosa, there is a marked decrease in the adipose tissue mass with the typical changes in adipocytokines secretion that occur in these circumstances. One of the most studied adipocytokine changes is decreased leptin secretion. Increased fat mass stores...

Obesity Associated with Recognized Medical Condition

There are conditions in which obesity is part of a recognized genetic defect, clinical syndrome, or acquired pathological condition (Table 2). Together, these conditions account for only a very small Table 2 Specific conditions associated with obesity in childhood Inherited syndromes associated with childhood obesity Inherited syndromes affecting mobility Inherited disorders of growth Chromosomal abnormalities Single gene defect affecting leptin metabolism Autosomal dominant Autosomal recessive...

Obesity

Obesity is not inevitable in Down's syndrome, but it is common. Obesity in children with Down's syndrome has been reported from different cultures and different ethnic backgrounds. From Australian and North American studies, it has been reported that by 2 or 3 years of age more than 30 of children with trisomy 21 are overweight, and by 9 years of age the average child with Down's syndrome is obese from the age of 10 years, the average weight of Dutch children with Down's syndrome is above the...

Reproductive System

Hormonal Complications Males Obese men have elevated levels of plasma estrone and estradiol that correlate with the degree of obesity. Plasma total testosterone and free testosterone (the biologically active moiety) are reduced in obese men, and the reductions correlate negatively with the degree of obesity. The reduced levels of free and total testosterone are not generally accompanied by hypogo-nadism or a decrease in libido, potency, or sperm count in obese men. Free and total plasma...

Breast feeding and Immunity to Infection

Human milk is the first form of nutrition for a neonate. Mammary glands are part of the integrated mucosal immune system and produce antibodies against mucosal pathogens that the mother is exposed to and which the infant is most likely to encounter. Breast milk contains several factors that protect against infections in the breast-fed infant either through passive immunity or by activating the infant's immune system. These include secretory IgA and IgM antibodies specific to maternal pathogenic...

Physiological Role Tissue Concentrations

The average human body contains between 200 and 400 mmol of manganese, which is fairly uniform in distribution throughout the body. There is relatively little variation among species with regard to tissue manganese concentrations. Manganese tends to be highest in tissues rich in mitochondria its concentration in mitochondria is higher than in cytoplasm or other cell organelles. Hair can accumulate high concentrations of manganese, and it has been suggested that hair manganese concentrations may...

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...

Effects of Dietary Fats and Cholesterol on Lipoprotein Metabolism

The cholesterolemic effects of dietary fatty acids have been extensively studied. The saturated fatty acids Ci2 o, C14 0, and C16 0 have a hypercholester-olemic effect, whereas Cig 0 has been shown to have a neutral effect. Monounsaturated and polyunsatu-rated fatty acids in their most common cis configuration are hypocholesterolemic in comparison with saturated fatty acids. The effects of trans fatty acids on lipid levels are under active investigation. Our current knowledge shows that their...

Effects of Diet on Chylomicron Metabolism

Diets very high in saturated fat have been associated with increased postprandial chylomicrons and chy-lomicron 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...

Effects of Diet on LDL Metabolism

The effects of dietary fat and cholesterol on LDL metabolism have been extensively studied. However, the effects of dietary cholesterol are still highly controversial. Whereas some studies have demonstrated increased LDL production and decreased catabolism associated with high cholesterol intakes, others have failed to find such associations. Replacement of saturated by polyunsaturated fats has been associated with decreased LDL apo B production in some studies, whereas in other studies,...

Familial Combined Hyperlipidemia

Familial combined hyperlipidemia (FCH) was initially described as the combination of hypercholester-olemia and hypertriglyceridemia within the same kindred, and with kindred members having one of these abnormalities or both. Moreover, most subjects with FCH have HDL cholesterol levels below the 10th percentile. Affected subjects have elevation in VLDL, LDL, or both. This disorder has a frequency of approximately 10 in survivors of premature myocardial infarction (less than 60 years of age) and...

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...

Familial Lipoprotein a Excess

Lipoprotein (a) (Lp(a)) is an LDL particle with one molecule of apolipoprotein (a) attached to it. Elevated levels of Lp(a) (> 35-40 mgdl-1 or 90th percentile) have been associated with premature CHD. This increased risk appears to result from two different mechanisms cholesterol deposition in the arterial wall and inhibition of fibrinolysis. Lp(a) concentrations are highly variable among individuals however, they tend to remain constant during a person's lifetime. Between 80 and 90 of the...

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...

Artificial Nutrition Support Home Parenteral Nutrition and Home Enteral Tube Feeding

Patients suffering from chronic conditions often prefer to be treated in the familiar surroundings of their home rather than in hospital. When the treatment involves sophisticated techniques, it is essential that either the patient or the caregiver is adequately trained to distinguish between problems that can be easily remedied at home and those that need expert advice and treatment in hospital. With the increasing pressure for hospital beds and the increasing cost of hospital care, many forms...

The Feeding Fasting Cycle Energy Requirements

Energy is essential for many important body functions, including the maintenance of cellular integrity and function, new tissue synthesis, thermoregulation, and Table 1 Metabolic features and laboratory parameters of starvation and fasting Uncomplicated protein energy malnutrition (Marasmus) Hypoalbuminemic malnutrition (Kwashiorkor) expenditure Nitrogen loss Water, sodium Hormonal Albumin Transferrin Total lymphocyte Early small increase in catecholamines, glucagon, cortisol, growth hormone...

Food Borne Infections during Pregnancy

For many years it has been recognized that food-borne antenatal infections may cause death or serious fetal damage. Women may be more susceptible to the effects of infection during pregnancy because of immunological changes leading to suppression of the immune system (most commonly cell-mediated immunity), probably as a result of increases in pregnancy-associated sex steroids, such as oestradiol or progesterone. Among the most common causes of diarrhea during pregnancy are several food- or...

Summary Episodic and Tonic Factors in the Regulation of Appetite

Endogenous 5-HT and leptin represent two aspects of negative feedback integral to the appetite control Figure 3 The integration of peripherally generated episodic and tonic signals critical to the expression of appetite. Signals generated by both meal consumption and fat deposition are integrated into a complex hypothalamic system of neuropeptides, which in turn either stimulate or inhibit subsequent food intake. Abbreviations 5-HT, serotonin aMSH, alpha melanocortin stimulating hormone AgRP,...