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Washington, DC, United States

Johnson J.,Macquarie University | Barnard N.D.,Physicians Committee for Responsible Medicine
Theoretical Medicine and Bioethics

Using an approach developed in the context of human bioethics, we argue that chimpanzees in research can be regarded as vulnerable subjects. This vulnerability is primarily due to communication barriers and situational factors - confinement and dependency - that make chimpanzees particularly susceptible to risks of harm and exploitation in experimental settings. In human research, individuals who are deemed vulnerable are accorded special protections. Using conceptual and moral resources developed in the context of research with vulnerable humans, we show how chimpanzees warrant additional safeguards against harm and exploitation paralleling those for human subjects. These safeguards should include empowering third parties to act as surrogate decision makers for chimpanzees, ensuring participant "assent," and avoiding recruitment of animal subjects based merely on convenience. © 2014 The Author(s). Source

Barnard N.D.,George Washington University | Levin S.M.,Physicians Committee for Responsible Medicine | Yokoyama Y.,Keio University
Journal of the Academy of Nutrition and Dietetics

In observational studies, vegetarians generally have lower body weights compared with omnivores. However, weight changes that occur when vegetarian diets are prescribed have not been well quantified. We estimated the effect on body weight when vegetarian diets are prescribed. We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials for articles through December 31, 2013. Additional articles were identified from reference lists. We included intervention trials in which participants were adults, interventions included vegetarian diets of ≥4 weeks' duration without energy intake limitations, and effects on body weight were reported. Two investigators independently extracted data using predetermined fields. Estimates of body weight change, comparing intervention groups to untreated control groups, were derived using a random effects model to estimate the weighted mean difference. To quantify effects on body weight of baseline weight, sex, age, study duration, study goals, type of diet, and study authorship, additional analyses examined within-group changes for all studies reporting variance data. We identified 15 trials (17 intervention groups), of which 4 included untreated controls. Prescription of vegetarian diets was associated with a mean weight change of -3.4 kg (95% CI -4.4 to -2.4; P<0.001) in an intention-to-treat analysis and -4.6 kg (95% CI -5.4 to -3.8; P<0.001) in a completer analysis (omitting missing post-intervention values). Greater weight loss was reported in studies with higher baseline weights, smaller proportions of female participants, older participants, or longer durations, and in studies in which weight loss was a goal. Using baseline data for missing values, I2 equaled 52.3 (P=0.10), indicating moderate heterogeneity. When missing data were omitted, I2 equaled 0 (P=0.65), indicating low heterogeneity. Studies are relatively few, with variable quality. The prescription of vegetarian diets reduces mean body weight, suggesting potential value for prevention and management of weight-related conditions. © 2015 Academy of Nutrition and Dietetics. Source

Barnard N.D.,George Washington University | Bunner A.E.,Physicians Committee for Responsible Medicine | Agarwal U.,Physicians Committee for Responsible Medicine
Neurobiology of Aging

Cognitive disorders of later life are potentially devastating. To estimate the relationship between saturated and trans fat intake and risk of cognitive disorders. PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for studies reporting saturated or trans fat intake and incident dementia, Alzheimer's disease (AD), or mild cognitive impairment (MCI) or cognitive decline. Only observational studies met the inclusion criteria: 4 for AD or other dementias, 4 for MCI, and 4 for cognitive decline. Saturated fat intake was positively associated with AD risk in 3 of 4 studies, whereas the fourth suggested an inverse relationship. Saturated fat intake was also positively associated with total dementia in 1 of 2 studies, with MCI in 1 of 4 studies, and with cognitive decline in 2 of 4 studies. Relationships between trans fat intake and dementia were examined in 3 reports with mixed results. Several, although not all, prospective studies indicate relationships between saturated and trans fat intake and risk of cognitive disorders. © 2014 The Authors. Source

Lai M.,Physicians Committee for Responsible Medicine | Chandrasekera P.C.,Physicians Committee for Responsible Medicine | Barnard N.D.,Physicians Committee for Responsible Medicine | Barnard N.D.,George Washington University
Nutrition and Diabetes

Obesity and type 2 diabetes mellitus (T2DM) are rapidly growing worldwide epidemics with major health consequences. Various human-based studies have confirmed that both genetic and environmental factors (particularly high-caloric diets and sedentary lifestyle) greatly contribute to human T2DM. Interactions between obesity, insulin resistance and β-cell dysfunction result in human T2DM, but the mechanisms regulating the interplay among these impairments remain unclear. Rodent models of high-fat diet (HFD)-induced obesity have been used widely to study human obesity and T2DM. With >9000 publications on PubMed over the past decade alone, many aspects of rodent T2DM have been elucidated; however, correlation to human obesity/diabetes remains poor. This review investigates the reasons for this translational discrepancy by critically evaluating rodent HFD models. Dietary modification in rodents appears to have limited translatable benefit for understanding and treating human obesity and diabetes due-at least in part-to divergent dietary compositions, species/strain and gender variability, inconsistent disease penetrance, severity and duration and lack of resemblance to human obesogenic pathophysiology. Therefore future research efforts dedicated to acquiring translationally relevant data-specifically human data, rather than findings based on rodent studies-would accelerate our understanding of disease mechanisms and development of therapeutics for human obesity/T2DM. © 2014 Macmillan Publishers Limited All rights reserved. Source

Cavanaugh S.E.,Physicians Committee for Responsible Medicine | Pippin J.J.,Physicians Committee for Responsible Medicine | Barnard N.D.,Physicians Committee for Responsible Medicine | Barnard N.D.,George Washington University

Alzheimer disease (AD) is a medically and financially overwhelming condition, and incidence rates are expected to triple by 2050. Despite decades of research in animal models of AD, the disease remains incompletely understood, with few treatment options. This review summarizes historical and current AD research efforts, with emphasis on the disparity between preclinical animal studies and the reality of human disease and how this has impacted clinical trials. We provide a mechanism for shifting the focus of AD research away from animal models to focus primarily on human biology as a means to improve the applicability of research findings to human disease. Implementation of these alternatives may hasten development of improved strategies to prevent, detect, ameliorate, and possibly cure this devastating disease. Source

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