Current Nutrition & Food Science - Volume 1, Issue 2, 2005

For the last decade there has been considerable interest in the possibility that undernutrition during fetal development may exert long-term effects on cardiovascular physiology, effectively predisposing the individual to hypertension and coronary heart disease. These epidemiological observations have been developed into the developmental origins of health and disease (DOHAD) hypothesis. The DOHAD hypothesis is based upon an extensive range of ecological and retrospective cohort studies of human populations. Due to the problems associated with modelling a dietdisease association over periods of 50-60 years and the large number of confounders that may act within such a period, the epidemiological studies have often been inconsistent and the hypothesis subjected to robust criticism. A broad range of animal models of developmental programming have been established to provide evidence of the biological plausibility of DOHAD, to refine the hypothesis and, more importantly, are the focus of studies that are investigating the mechanisms that link poor maternal nutrition in pregnancy with long-term disease in the resulting offspring. This review considers nutritional programming of kidney development as a critical step in the development of non-essential hypertension and explores the involvement of the renin-angiotensin system, angiotensin receptors, glucocorticoids and epigenetic mechanisms in the association between fetal undernutrition and disease in adult life.

Gastroesophageal reflux (GER) is usually a self-resolving phenomenon during infancy, however, some intervention is frequently needed to allay parental anxiety and stress. Older children and adolescents need dietary advice in addition to pharmacologic intervention because they are more likely to have gastroesophageal reflux disease. Management depends on the age and severity of the child's symptoms. In infants with mild symptoms, attention to feeding technique, volume, frequency, use of pre-thickened formula and an upright position for at least 30 minutes after a feeding may suffice. If food allergy is suspected, a 2-4 week trial of a hydrolysed formula may be appropriate. Older children and adolescents may benefit from a combination of dietary and lifestyle measures.Encouraging small, frequent meals and avoidance of foods identified to cause symptoms is an obvious consideration. In presence of obesity, weight loss may improve GER symptoms. Since unnecessary dietery restrictions impair the quality of life for patients and parents, a rational, nutritional therapeutic approach is recommended.

Parents have always been concerned about the eating habits of their children. One should be as cautious of the uncritical use in children of products designed for adults, as one should be observing the counter arguments that products designed for adults should never be used in children because they have never been tested in children. The nutritional requirements for adults and children differ. Although the chemical composition of organs differs according to age, organ size is a factor that changes much more according to age. The accurate assessment of food intake in children and adolescents is of concern because dietary habits formed early in life in response to physiological requirements and psycho-social pressures may have considerable impact on long-term health status. Future research should focus on refining dietary survey methods to make them more sensitive to different ages. Regarding nutrient requirements and dietary habits, children cannot be considered as small adults.

Patients with cancer are at risk of malnutrition due to a number of factors, including decreased energy intake, increased energy needs, and/or poor assimilation of dietary intake. The nutritional status of patients undergoing HSCT, however, has not been widely studied. After two influential studies showed better medical outcomes among children with the use of parenteral nutrition (PN) immediately following transplantation, PN became an accepted part of supportive care during HSCT. PN is generally provided to these patients in the amount of 120-140% of estimated basal energy needs, for as long as oral intake is unable to meet dietary energy needs. This process may take 2-4 weeks or longer after transplantation. In order to more fully evaluate the energy needs of pediatric patients undergoing HSCT, we recently performed indirect calorimetry in a cohort of 25 HSCT patients at baseline, and then weekly during the month following transplantation. Detailed dietary intake and laboratory measures of nutritional status were also obtained. We found significant declines in resting energy expenditure (REE) after transplantation. We review the results of our study in light of other studies of energy expenditure in the setting of HSCT. Should our results be replicated, it seems likely that current recommendations for providing nutritional support in HSCT patients may lead to significant overfeeding.

Meat is a nutrient dense food and meat and meat products are an important source of a wide range of nutrients. The protein content of meat is of high biological value with many essential amino acids. However, meat has been criticised for its fat content and addressing concerns with fat intakes, the meat industry has reduced the fat content of meat over the last 20 years. Meat is important source of B vitamins, especially thiamin, riboflavin and vitamin B12. Furthermore, meat provides large quantities of bioavailable micronutrients particularly iron, zinc, and vitamins A and D, which may not be obtained from other dietary sources. Conversely, meat consumption has been negatively linked with an increased risk of colorectal cancers, cardiovascular disease and most recently, obesity and type 2 diabetes. Specifically with regard to cancer risk, there is no agreement as to whether it is the type of meat, its fat content and fatty acid profiles, protein or iron content, the formation of carcinogens (e.g. heterocyclic amines) during cooking the addition of nitrates during preparation that are potential risk factors. Meat is a diverse food group encompassing cuts, processed and composite foods. Consequently, not all meat types make similar contributions to the diet or health outcomes. This review examines the potential positive role of meat in the diet while considering dietary recommendations and reviews some of the current epidemiological studies in relation to meat and disease risk.

With the advent of new knowledge and technologies, the survival of critically ill premature neonates has much improved compared to the last decade. One of these is parenteral nutrition (PN). Despite the magnificent benefits, longterm PN can contribute to many life-threatening complications. The parenteral nutrition-associated liver disease comprises one of the potential complications, leading to hepatic fibrosis, cirrhosis, portal hypertension, and death if liver transplantation is not performed. Its pathophysiology is still obscure, although many offending factors have been postulated, including total caloric intake, glucose and amino acid concentration, composition of the amino acid solutions, phytosterols in lipid emulsions, infection, and lack of enteral stimulation. Because there is no specific biological marker or histopathology for this condition, the definite diagnosis is exclusively based on a history of receiving long-term PN and exclusion of other possible causes of neonatal cholestasis, most importantly biliary atresia. Recent reports using ursodeoxycholic acid and cholecystokinin-octapeptide for treatment of PN-induced cholestasis have shown promising results. However, early minimal enteral feeding and prevention of catheter-related sepsis are still the mainstay of preventive measures.

Several studies have provided support for the protective effects of long chain n-3 polyunsaturated fatty acids (n-3 PUFA) against cardiovascular disease (CVD). N-3 PUFA may decrease the risk of CVD by improving plaque stability and endothelial activation and/or function. Compared with the considerable amount of literature describing the effects of n-3 PUFA on CVD, relatively little consistent information is available about the mechanism by which this occurs. The aim of this review is to overview the literature that provides insight into our current understanding of the mechanisms by which PUFA improve endothelial function and assist in plaque stabilization in atherosclerosis.

PPARs are receptors for a highly diverse set of natural lipid molecules of nutritional or endogenous origin. While PPARs are involved in the regulation of metabolic, immune and inflammatory processes, no studies are available that integrate the metabolic and immunomodulatory properties of these receptors. Due to the therapeutic significance of selective agonists, the scientific understanding of PPARs biology derives primarily from experiments that utilized synthetic ligands. However, PPARs have existed in nature for millions of years prior to the development of synthetic ligands. This observation further supports the importance of endogenous/nutritional ligands as regulators of PPAR function. Therefore, the predominantly drug-based investigative approach may not reflect the actual physiological function of PPARs. The goal of this review article is to provide an integrative vision on the role of PPAR α, β/δ and γ, in the interface between metabolic and immunoinflammatory diseases. We will also discuss the differences and similarities between the effects of synthetic and natural PPAR agonists, and examine the actions of the three isoforms both separately and as a part of interconnected nuclear receptor networks. Finally, we will discuss the possible role of adipose tissue as an organ of innate immunity and the link between visceral adipose tissue accumulation and chronic, low-grade inflammatory responses. The better understanding of adipose tissue as an immunoendocrine organ may facilitate the development of novel PPAR-based interventions against metabolic and immune disorders.