Current Nutrition & Food Science - Volume 2, Issue 3, 2006

In this paper, we discuss how interactions between dietary xenobiotics and nutrients influence cancer risk by modulating overlapping biochemical pathways leading to repression of tumor suppressor genes, activation of tumor promoters, or both. Epidemiologic studies in humans suggested that diet is an important vehicle of exposure to various xenobiotics, including polycyclic aromatic hydrocarbons (PAHs), dioxins, and chlorinated hydrocarbons (CHs). The activation of the aromatic hydrocarbon receptor (AhR) pathway by PAHs and dioxins stimulates the expression of several genes including cytochrome P450s, which metabolize PAHs to highly mutagenic compounds that cause fixation of mutations in the p53 gene and repress the expression of the tumor suppressor gene, BRCA-1. Conversely, PAHs and dioxins have been shown to activate the expression of cyclooxygenase-2 (COX-2), whose protein product participates in the production of reactive PAH-metabolites and synthesis of proinflammatory prostaglandins (PGs). The carcinogenicity of CHs has been attributed to their ability to activate the expression of oncogenes including c-myc, and fatty acid activation of the peroxisome proliferator-activated receptor-α (PPARα). Dietary components that may protect against the activation of the AhR pathway include flavonoids, which comprise a large family of dietary phenolic phytochemicals found in fruits and vegetables. Nutrients such as dietary fatty acids may differentially influence the risk of cancer by inducing (linoleic and arachidonic acid) or repressing (conjugated linoleic acid (CLA); n-3PUFA) the expression of COX- 2. Finally, we present original findings produced in our laboratory documenting the protective effects of natural (genestein) and synthetic (α-naphthoflavone) flavonoids against PAH-induced changes in gene expression.

The prevalence of obesity among children and adolescents is increasing rapidly. In Germany, between 10 - 20% of children are overweight or obese. Besides, a possible genetic predisposition and excessive energy intake, decreased physical activity and a sedentary lifestyle have been implicated as risk factors. Data about children's activity and its correlation with obesity are sparse and also inconsistent, as different measurement criteria are used. Some authors found differences between the fitness of obese and non-obese children, while others did not. Several studies described worse results in motor abilities with overweight children compared to their normal weight counterparts, especially in coordination and endurance performance. There is a general agreement that obese children prefer sedentary habits, mainly audio-visual media like television and PC. The incidence of obesity increases with a daily television consumption of more than five hours. But to what extent, with what intensity, and which sports/exercise techniques are suitable and necessary for preventive measures is not precisely known. As a result, recommendations for daily routine and physical activities as well as minimal requirements can hardly be formulated. This paper presents the current aspects of the role of physical activity in the development and prevention of overweight and obesity during childhood.

Fructose consumption per capita has increased markedly over the past decades and is thought to be related with the increased incidence of obesity and metabolic disorders worldwide. Fructose metabolism is mainly hepatic, for its first step at least, and does not require insulin. It was therefore initially thought to be of potential benefit in the dietary management of patients with impaired glucose homeostasis. Long term fructose administration, however, led to the development of hypertriglyceridemia in humans. In addition, it was associated with the development of impaired glucose homeostasis and high blood pressure in rodents. Stimulation of de novo lipogenesis is a major effect of dietary fructose. Recent evidence indicates that hepatic de novo lipogenesis may be directly linked to intrahepatic fat accumulation and hepatic insulin resistance. Furthermore, hyperlipidemia secondary to enhanced hepatic de novo lipogenesis may possibly lead to lipid accumulation in muscle and muscle lipotoxicity, thus resulting in impaired muscle glucose metabolism. This article reviews the present state of knowledge regarding the effects of fructose on whole body lipid metabolism and its possible relationship with the metabolic syndrome.

This review describes data sources for assessing the prevalence of overweight and obesity in the entire U.S. population, and some examples of surveillance in specific subpopulations (i.e., schoolchildren, military, and athletes). On the basis of body mass index (ratio of weight in kg to height in m2) of 30 or higher from body measurement, which is more accurate than self-reported data, the prevalence of obesity among U.S. adults increased markedly in recent decades. Obesity prevalence has differed little by race-ethnicity among males but is higher in minority vs. white females. For waist circumference, a measure of abdominal obesity associated with various chronic diseases, the temporal increases in prevalence among U.S. adults are also striking. Obesity prevalence is higher in certain states and metropolitan areas in the South. Population surveillance of risk factors (e.g., diet, physical activity, and neighborhood characteristics) may be useful in interpreting temporal and geographic variation in obesity and obesity-related medical conditions.

The term dietary fibre describes a wide range of highly divergent (mainly polysaccharide) compounds that escape digestion before the colon. Fibre is often regarded as a neutral dietary compound, not interacting with the gut and only offering dietary "benefit" by the consequent absence of calorific macronutrients, or by bulking out luminal content. Although the above benefits are apparent, a number of other physiological effects of dietary fibres in the colon have previously been described. This review outlines these previous observations in terms of the effect of various fibre types on (i) colonic luminal contents (including the resident microflora (ii) the first line of colonic protection, the mucus barrier (iii) the underlying colonic mucosa (iv) the colonic musculature and (v) colonic neurohumoural release, and the subsequent effect on control of gut motility and satiety. This review will further highlight the divergent physiological effects of various fibre types, and their potential health benefits.

In the early 60s, data from the Seven Countries Study demonstrated that diet was a key risk factor for cardiovascular disease (CVD). Several epidemiological studies have since then provided further support to this concept by demonstrating that adherence to a Mediterranean food pattern was associated with a reduction in total and CVD mortality. The mechanisms underlying the cardioprotective effects of the Mediterranean diet (MEDdiet) remain unclear. Our objective was to provide an overview of how a Mediterranean food pattern modulates traditional and non-traditional risk factors for CVD. Data reviewed herein indicated that the MEDdiet may beneficially alter total cholesterol, LDL-C and TG levels, although this has not been a consistent finding. However, the impact of the MEDdiet on non-traditional risk factors such as a lower plasma apolipoprotein B concentrations, a lower high-sensitivity C-reactive protein and interleukin-6 levels, and a better endothelial function appears to be more consistent. In conclusion, adherence to a MEDdiet has been almost unequivocally associated with a decrease in mortality and this may be largely attributable to the more consistent impact of this food pattern on non-traditional risk factors for CVD rather than on traditional risk factors.

Within the past three decades, the percentage of children who are overweight or at risk for overweight has more than doubled. Pediatric overweight negatively affects physical and psychological well-being, and overweight children are at high risk of becoming obese adults. Several parental variables are associated with childhood eating and weight problems, including genetics, feeding style, and role modeling of eating behaviors and attitudes. Parental restriction appears to be associated with unhealthy eating behaviors in children, particularly Caucasian girls. However, it is unknown whether parental restriction of access to highly palatable foods causes disinhibited eating and overweight in children, or if parents restrict in response to children's overeating. Additionally, parental disinhibition seems to impact children's eating behaviors negatively. Further, disinhibition appears to be strongly influenced by genetic factors; certain individuals may be predisposed to eat in response to environmental cues. In sum, many questions about parental factors associated with children's eating behaviors remain. In addition to summarizing the literature, this review highlights areas where further investigation is needed. Finally, we provide preliminary suggestions for practitioners and others working with parents concerned about their children’s eating and weight, and highlight the need for intervention at multiple levels.

Obesity is a serious health problem not only in the United States but also throughout the world. It is generally recognized that complications of the overweight state and obesity are responsible for thousands of deaths each year, because excess fat accumulation is associated with heart disease, stroke, and diabetes that significantly reduce life expectancy. Many have come to realize that most individuals, especially when elderly, require aids to prevent or overcome obesity and maintain a reasonable body fat mass. A restricted caloric diet and regular exercise remain the cornerstones of prevention and therapy; however, the average overweight individual cannot sustain the necessary therapeutic disciplines and needs safe, complementary means to supplement diet and exercise. Up to this point, drugs are not the answer due to safety concerns, leading many to seek safer, natural alternatives. Recently, oral intake of chitosan, a soluble fiber with reputed special properties, has become one possible solution to the problem. This review examines chitosan as an aid in the battle against fat accumulation.

The book contains 14 chapters, distributed into 5 parts, that range in length from approximately 10 to 12 pages. The introductory chapter is addressing a general perspective of the book, its organization and main goals, giving also some misguided perspectives on marketing nutrition of four hypothetical people: a dietitian, a government administrator, a marketing manager, and a researcher. Part 1 deals with the secrets about food and people. It starts looking at the gap between what people know and what they do, emphasizing the importance of nutritional knowledge. It follows with some curious materials (declassified Department of Defence documents) and finishes illustrating that the tastes of consumers are very suggestible. For instance, the author states that descriptive names for foods make people taste what they believe they will taste. Part 2 describes the tools for targeting. The first two chapters examine techniques useful to identify the taste preferences among a number of market segments. It examines the importance of profiling as a method to better understand who the perfect consumers are and also a kind of mental mapping to understand why consumers act as they do. This part is finished with the influence of cooking for consumers to make a selection of nutritional foods and targeting. Part 3 is focused on the health of nations. This part addresses the five main drivers of food consumption, why the 5-a-day programs often fail in the objective, the need for marketers to continue evaluating benefits and risks of biotechnology and, finally