Norman Alan Greenberg

The role of nucleotides in the immune and gastrointestinal systems: potential clinical applications.

Nucleotides are low molecular weight biological molecules key to biochemical processes. Sources include de novo synthesis, recovery via salvage mechanisms, and dietary intakes. Although endogenous production serves as the main nucleotide source, evidence suggests that exogenous sources are essential to immune competence, intestinal development, and recovery. Dietary nucleotides serve a marked role in rapidly proliferating cells where they are necessary for optimal function. Accordingly, dietary nucleotides are deemed conditionally essential in the presence of various physiological stresses, including growth and development, recovery from injury, infection, and certain disease states. Clinical studies that evaluated nutrition formulations of nucleotides in combination with other specific nutrient substances demonstrated improved clinical outcomes in patients characterized as critically ill, injured, immune suppressed, or with chronic gastrointestinal conditions. However, conclusions regarding specific benefits of nucleotides are limited. Scientific substantiation of nucleotide supplementation in infant formula has been reported to improve the maturation and development of the intestinal tract as well as immune function. All medical nutrition products except for one immune-modulating formulation are devoid of nucleotides. In an effort to build on this, the current review presents the data to support potential clinical applications for nucleotides in enteral nutrition that may contribute to improved outcomes in physiologically stressed patients.

Investigation of effect of nutritional drink on chemotherapy-induced mucosal injury and tumor growth in an established animal model.

Chemotherapy-induced mucositis represents a significant burden to quality of life and healthcare costs, and may be improved through enhanced nutritional status. We first determined the safety of two nutritional drinks (plus placebo), and then potential gut protection in tumor-bearing rats in a model of methotrexate-induced mucositis. In study 1, animals were fed one of two test diets (or placebo or control chow pellets) for a total of 60 days and were monitored daily. All diets were found to be safe to administer. In study 2, after seven days of receiving diets, a Dark Agouti Mammary Adenocarcinoma (DAMA) was transplanted subcutaneously. Ten days after starting diets, animals had 2 mg/kg intramuscular methotrexate administered on two consecutive days; after this time, all animals were given soaked chow. Animals were monitored daily for changes in bodyweight, tumor burden and general health. Animals were killed 10, 12 and 16 days after initially starting diets, and tissues were collected at necropsy. In study 1, animals receiving diets had gained 0.8% and 10.8% of their starting bodyweight after 60 days, placebo animals 4.4%, and animals fed on standard chow had gained 15.1%. In study 2, there was no significant influence of test diet on bodyweight, organ weight, tumor burden or biochemical parameters. Only animals treated with MTX exhibited diarrhea, although animals receiving Diet A and Diet C showed a non-significant increase in incidence of diarrhea. Administration of these nutritional drinks did not improve symptoms of mucositis.

Nutritional Ketosis Increases NAD+/NADH Ratio in Healthy Human Brain: An in Vivo Study by 31P-MRS

Ketones represent an important alternative fuel for the brain under glucose hypo-metabolic conditions induced by neurological diseases or aging, however their metabolic consequences in healthy brain remain unclear. Here we report that ketones can increase the redox NAD+/NADH ratio in the resting brain of healthy young adults. As NAD is an important energetic and signaling metabolic modulator, these results provide mechanistic clues on how nutritional ketosis might contribute to the preservation of brain health.

Natural Bioactive Food Components for Improving Enteral Tube Feeding Tolerance in Adult Patient Populations

Tube feeding (TF) is the most common form of nutrition support. In recent years, TF administration has increased among patient populations within and outside hospital settings, in part due to greater insurance coverage, reduced use of parenteral nutrition, and improved formularies suitable for sole source nutrition. With increasing life expectancy and improved access to TFs, the number of adults dependent on enteral nutrition is expected to grow. However, enteral TF intolerance (ETFI) is the most common complication of TFs, typically presenting with at least 1 adverse gastrointestinal event, including nausea, diarrhea, and constipation. ETFI often leads to reductions in TF volume with associated energy and protein deficits. Potentially ensuing malnutrition is a major public health concern due its effects on increased risk of morbidity and mortality, infections, prolonged hospital length of stay, and higher healthcare costs. As such, there is a need for intervention strategies to prevent and reduce ETFI. Incorporating whole foods with bioactive properties is a promising strategy. Emerging research has elucidated bioactive properties of whole foods with specific benefits for the prevention and management of adverse gastrointestinal events commonly associated with TFs. However, lack of evidence-based recommendations and technological challenges have limited the use of such foods in commercial TF formulas. This review addresses research gaps by discussing 5 whole foods (rhubarb, banana, curcumin, peppermint oil, and ginger) with bioactive attributes identified through literature searches and clinical experience as having substantial scientific rationale to consider their application for ETFI in adult populations.

Nutrition in Clinical Practice

Features: NEW data from hundreds of recent studies NEW section: Contemporary Topics in Nutrition Easy-reference format includes short chapters, links to current online articles Contributors representing diverse expertise and practical experience with medical education, nutrition in clinical practice, and preventive medicine Enhanced coverage of controversial topics, such as, the effects of sugar; health effects of obesity and the ‘obesity paradox’; health effects of gluten and grains; nutritional therapy Appendices includes ancillary materials such as clinically relevant formulas, nutrition data tables, and patient specific meal planners, all fully updated