Recent Reviews on Studies of Nutritional Therapy and Health
Compiled by Kevin W Chen
Policy Interventions To Promote Healthy Eating : A Review of What Works, What Does Not and What Is Promising. Food Nutrition Bulletin. 2011 Dec;32(4):365-75. By Brambila-Macias J, Shankar B, Capacci S, Mazzocchi M, Perez-Cueto FJ, Verbeke W, Traill WB. From University of Reading, Reading, UK.
Abstract: Unhealthy diets can lead to various diseases, which in turn can translate into a bigger burden for the state in the form of health services and lost production. Obesity alone has enormous costs and claims thousands of lives every year. Although diet quality in the European Union has improved across countries, it still falls well short of conformity with the World Health Organization dietary guidelines. In this review, we classify types of policy interventions addressing healthy eating and identify through a literature review what specific policy interventions are better suited to improve diets. Policy interventions are classified into two broad categories: information measures and measures targeting the market environment. Using this classification, we summarize a number of previous systematic reviews, academic papers, and institutional reports and draw some conclusions about their effectiveness. Of the information measures, policy interventions aimed at reducing or banning unhealthy food advertisements generally have had a weak positive effect on improving diets, while public information campaigns have been successful in raising awareness of unhealthy eating but have failed to translate the message into action. Nutritional labeling allows for informed choice. However, informed choice is not necessarily healthier; knowing or being able to read and interpret nutritional labeling on food purchased does not necessarily result in consumption of healthier foods. Interventions targeting the market environment, such as fiscal measures and nutrient, food, and diet standards, are rarer and generally more effective, though more intrusive. Overall, we conclude that measures to support informed choice have a mixed and limited record of success. On the other hand, measures to target the market environment are more intrusive but may be more effective.
Nutritional Support in COPD Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis
American Journal Clinical Nutrition. 2012 Jun;95(6):1385-95. By Collins PF, Stratton RJ, Elia M. from Institute of Human Nutrition, University of Southampton, Southampton, UK.
Background: The efficacy of nutritional support in the management of malnutrition in chronic obstructive pulmonary disease (COPD) is controversial. Previous meta-analyses, based on only cross-sectional analysis at the end of intervention trials, found no evidence of improved outcomes. Objective: The objective was to conduct a meta-analysis of randomized controlled trials (RCTs) to clarify the efficacy of nutritional support in improving intake, anthropometric measures, and grip strength in stable COPD.
Design: Literature databases were searched to identify RCTs comparing nutritional support with controls in stable COPD. Results: Thirteen RCTs (n = 439) of nutritional support [dietary advice (1 RCT), oral nutritional supplements (ONS; 11 RCTs), and enteral tube feeding (1 RCT)] with a control comparison were identified. An analysis of the changes induced by nutritional support and those obtained only at the end of the intervention showed significantly greater increases in mean total protein and energy intakes with nutritional support of 14.8 g and 236 kcal daily. Meta-analyses also showed greater mean (±SE) improvements in favor of nutritional support for body weight (1.94 ± 0.26 kg, P < 0.001; 11 studies, n = 308) and grip strength (5.3%, P < 0.050; 4 studies, n = 156), which was not shown by ANOVA at the end of the intervention, largely because of bias associated with baseline imbalance between groups. Conclusion: This systematic review and meta-analysis showed that nutritional support, mainly in the form of ONS, improves total intake, anthropometric measures, and grip strength in COPD. These results contrast with the results of previous analyses that were based on only cross-sectional measures at the end of intervention trials.
Fish Consumption, Dietary Long – Chain N-3 Fatty Acids and Risk of Type 2 Diabetes: Systematic Review and Meta-Analysis of Prospective Studies
Objective: The evidence on the association between fish consumption, dietary long-chain n-3 fatty acids, and risk of type 2 diabetes is inconsistent. We therefore performed a systematic review and meta-analysis of the available prospective evidence. Research and Design Methods: Studies were identified by searching the PubMed and EMBASE databases through 15 December 2011 and by reviewing the reference lists of retrieved articles. Prospective studies were included if they reported relative risk (RR) estimates with 95% CIs for the association between fish consumption and/or dietary long-chain n-3 fatty acids and incidence of type 2 diabetes. A dose-response random-effects model was used to combine study-specific RRs. Potential sources of heterogeneity were explored by prespecified stratifications. Results: Sixteen studies involving 527,441 participants and 24,082 diabetes cases were included. Considerable statistical heterogeneity in the overall summary estimates was partly explained by geographical differences. For each serving per week increment in fish consumption, the RRs (95% CIs) of type 2 diabetes were 1.05 (1.02-1.09), 1.03 (0.96-1.11), and 0.98 (0.97-1.00) combining U.S., European, and Asian/Australian studies, respectively. For each 0.30 g per day increment in long-chain n-3 fatty acids, the corresponding summary estimates were 1.17 (1.09-1.26), 0.98 (0.70-1.37), and 0.90 (0.82-0.98). CONCLUSIONS: Results from this meta-analysis indicate differences between geographical regions in observed associations of fish consumption and dietary intake of long-chain n-3 fatty acids with risk of type 2 diabetes. In consideration of the heterogeneous results, the relationship warrants further investigation. Meanwhile, current public health recommendations on fish consumption should be upheld unchanged.
Beyond Overweight: Nutrition As An Important Lifestyle Factor Influencing Timing of Puberty
Nutrition Review. 2012 Mar;70(3):133-52. by Cheng G, Buyken AE, Shi L, Karaolis-Danckert N, Kroke A, Wudy SA, Degen GH, Remer T. from Research Institute of Child Nutrition, Rheinische Friedrich-Wilhelms-University Bonn, Heinstueck 11, Dortmund, Germany. email@example.com
Abstract: Early onset of puberty may confer adverse health consequences. Thus, modifiable factors influencing the timing of puberty are of public health interest. Childhood overweight as a factor in the earlier onset of menarche has been supported by prospective evidence; nonetheless, its overall contribution may have been overemphasized, since secular trends toward a younger age at menarche have not been a universal finding during the recent obesity epidemic. Current observational studies suggest notable associations between dietary intakes and pubertal timing beyond contributions to an energy imbalance: children with the highest intakes of vegetable protein or animal protein experience pubertal onset up to 7 months later or 7 months earlier, respectively. Furthermore, girls with high isoflavone intakes may experience the onset of breast development and peak height velocity approximately 7-8 months later. These effect sizes are on the order of those observed for potentially neuroactive steroid hormones. Thus, dietary patterns characterized by higher intakes of vegetable protein and isoflavones and lower intakes of animal protein may contribute to a lower risk of breast cancer or a lower total mortality.
Effect of Fructose on Body Weight In Controlled Feeding Trials: A Systematic Review and Meta-Analysis
Annals of Internal Medicine. 2012 Feb 21;156(4):291-304. By Sievenpiper JL, de Souza RJ, Mirrahimi A, et al. from Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Background: The contribution of fructose consumption in Western diets to overweight and obesity in populations remains uncertain. Purpose: To review the effects of fructose on body weight in controlled feeding trials. Data Sources: MEDLINE, EMBASE, CINAHL, and the Cochrane Library (through 18 November 2011). Study Selection: At least 3 reviewers identified controlled feeding trials lasting 7 or more days that compared the effect on body weight of free fructose and nonfructose carbohydrate in diets providing similar calories (isocaloric trials) or of diets supplemented with free fructose to provide excess energy and usual or control diets (hypercaloric trials). Trials evaluating high-fructose corn syrup (42% to 55% free fructose) were excluded. Data Extraction: The reviewers independently reviewed and extracted relevant data; disagreements were reconciled by consensus. The Heyland Methodological Quality Score was used to assess study quality. Data Synthesis: Thirty-one isocaloric trials (637 participants) and 10 hypercaloric trials (119 participants) were included; studies tended to be small (<15 participants), short (<12 weeks), and of low quality. Fructose had no overall effect on body weight in isocaloric trials (mean difference, -0.14 kg [95% CI, -0.37 to 0.10 kg] for fructose compared with nonfructose carbohydrate). High doses of fructose in hypercaloric trials (+104 to 250 g/d, +18% to 97% of total daily energy intake) lead to significant increases in weight (mean difference, 0.53 kg [CI, 0.26 to 0.79 kg] with fructose). Limitations: Most trials had methodological limitations and were of poor quality. The weight-increasing effect of fructose in hypercaloric trials may have been attributable to excess energy rather than fructose itself. Conclusion: Fructose does not seem to cause weight gain when it is substituted for other carbohydrates in diets providing similar calories. Free fructose at high doses that provided excess calories modestly increased body weight, an effect that may be due to the extra calories rather than the fructose.
Oral Nutritional Interventions in Malnourished Patients With Cancer: A Systematic Review and Meta-Analysis
Journal National Cancer Institute. 2012 Mar 7;104(5):371-85. By Baldwin C, Spiro A, Ahern R, Emery PW. from Division of Diabetes and Nutritional Sciences, School of Medicine, King’s College London, Franklin Wilkins Bldg, 150 Stamford St, London SE1 9NH, UK. firstname.lastname@example.org
Background: International guidelines on the nutritional management of patients with cancer recommend intervention with dietary advice and/or oral nutritional supplements in patients who are malnourished or those judged to be at nutritional risk, but the evidence base for these recommendations is lacking. We examined the effect of oral nutritional interventions in this population on nutritional and clinical outcomes and quality of life (QOL). Methods: Electronic searches of several databases including MEDLINE, EMBASE, and CINAHL (from the first record to February 2010) were searched to identify randomized controlled trials of patients with cancer who were malnourished or considered to be at risk of malnutrition and receiving oral nutritional support compared with routine care. We performed a meta-analysis using a fixed effect model, or random effects models when statistically significant heterogeneity was present, to calculate relative risk (mortality) or mean difference (weight, energy intake, and QOL) with 95% confidence intervals (CIs). Heterogeneity was determined by using the χ(2) test and the I(2) statistic. All statistical tests were two-sided. Results: Thirteen studies were identified and included 1414 participants. The quality of the studies varied, and there was considerable clinical and statistical heterogeneity. Nutritional intervention was associated with statistically significant improvements in weight and energy intake compared with routine care (mean difference in weight = 1.86 kg, 95% CI = 0.25 to 3.47, P = .02; and mean difference in energy intake = 432 kcal/d, 95% CI = 172 to 693, P = .001). However, after removing the main sources of heterogeneity, there was no statistically significant difference in weight gain or energy intake. Nutritional intervention had a beneficial effect on some aspects of QOL (emotional functioning, dyspnea, loss of appetite, and global QOL) but had no effect on mortality (relative risk = 1.06, 95% CI = 0.92 to 1.22, P = .43; I(2) = 0%; P(heterogeneity) = .56). Conclusion: Oral nutritional interventions are effective at increasing nutritional intake and improving some aspects of QOL in patients with cancer who are malnourished or are at nutritional risk but do not appear to improve mortality.
Research Advances for the Institute for Nutritional Sciences at Shanghai, China
Advances in Nutrition. 2011 Sep;2(5):428-39. By Chen Y, Lin X, Liu Y, Xie D, Fang J, Le Y, et al. from Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China. email@example.com
Abstract: Nutrition-related health issues have emerged as a major threat to public health since the rebirth of the economy in China starting in the 1980s. To meet this challenge, the Chinese Academy of Sciences established the Institute for Nutritional Sciences (INS) at Shanghai, China ≈ 8 y ago. The mission of the INS is to apply modern technologies and concepts in nutritional research to understand the molecular mechanism and provide means of intervention in the combat against nutrition-related diseases, including type 2 diabetes, metabolic syndrome, obesity, cardiovascular diseases, and many types of cancers. Through diligent and orchestrated efforts by INS scientists, graduate students, and research staff in the past few years, the INS has become the leading institution in China in the areas of basic nutritional research and metabolic regulation. Scientists at the INS have made important progress in many areas, including the characterization of genetic and nutritional properties of the Chinese population, metabolic control associated with nutrient sensing, molecular mechanisms underlying glucose and lipid metabolism, regulation of metabolism by adipokines and inflammatory pathways, disease intervention using functional foods or extracts of Chinese herbs, and many biological studies related to carcinogenesis. The INS will continue its efforts in understanding the optimal nutritional needs for Chinese people and the molecular causes associated with metabolic diseases, thus paving the way for effective and individualized intervention in the future. This review highlights the major research endeavors undertaken by INS scientists in recent years.
Omega 3 Fatty Acid Nutritional Landscape: Health Benefits and Sources
Journal of Nutrition. 2012 Mar;142(3):587S-591S. By Deckelbaum RJ, Torrejon C. from Institute of Human Nutrition, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA. firstname.lastname@example.org
Abstract: Dietary fatty acids (FA) are increasingly recognized as major biologic regulators and have properties that relate to health outcomes and disease. The longer chain, more bioactive (n-6) (or omega-6) FA and (n-3) (or omega-3) FA share similar elongation and desaturation enzymes in their conversion from the essential (n-6) FA, linoleic acid, and (n-3) FA, α-linolenic acid (ALA). Conversion from these essential FA is very inefficient. However, now for the (n-3) FA series, soy oil can be enriched with (n-3) stearidonic acid (SDA) to allow for much more efficient conversion to longer chain EPA. EPA and the longer chain DHA possess distinct physical and biological properties that generally impart properties to cells and tissue, which underlie their ability to promote health and prevent disease. Although active in a number of areas of human biology, mechanisms of action of EPA and DHA are perhaps best defined in cardiovascular disease. There is concern that to reach the intake recommendations of EPA and DHA, their supply from cold water fish will be insufficient. Gaps in understanding mechanisms of action of (n-3) FA in a number of health and disease areas as well as optimal sources and intake levels for each need to be defined by further research. Because of the inefficient conversion of ALA, the appearance of SDA in enriched soy oil offers a biologically effective and cost effective approach to providing a sustainable plant source for (n-3) FA in the future.
Effectiveness of Agricultural Interventions That Aim to Improve Nutritional Status of Children: Systematic Review
British Medical Journal. 2012 Jan 17;344. By Masset E, Haddad L, Cornelius A, Isaza-Castro J. from Institute of Development Studies, University of Sussex, Brighton BN1 9RE, UK. email@example.com
Objective: To assess the effectiveness of agricultural interventions in improving the nutritional status of children in developing countries. Design: Systematic review. Data Sources: Published and unpublished reports (after 1990) in English identified by searching 10 databases (Agris, Econlit, Eldis, IBSS, IDEAS, IFPRI, Jolis, PubMed, Web of Science, and World Bank), websites, previous systematic reviews, and reference lists and by contacting experts. Study Selection: Included studies assessed effects of agricultural interventions aiming at improving the nutritional status of children (bio-fortification, home gardens, small scale fisheries and aquaculture, dairy development, and animal husbandry and poultry development). Only studies that used a valid counterfactual analysis were included. Before/after studies and participants/non-participants comparisons affected by selection bias were excluded. Data analysis Results were analysed for four intermediate outcomes (programme participation, income, dietary diversity, and micronutrient intake) and one final outcome (prevalence of under-nutrition). Analysis was by summary tables of mean effects and by meta-analysis (for vitamin A absorption).
Results: The review included 23 studies, mostly evaluating home garden interventions. The studies reviewed did not report participation rates or the characteristics of participants in programmes. The interventions had a positive effect on the production of the agricultural goods promoted, but not on households’ total income. The interventions were successful in promoting the consumption of food rich in protein and micronutrients, but the effect on the overall diet of poor people remains unclear. No evidence was found of an effect on the absorption of iron, but some evidence exists of a positive effect on absorption of vitamin A. Very little evidence was found of a positive effect on the prevalence of stunting, wasting, and underweight among children aged under 5. Conclusions: The question posed by the review cannot be answered with any level of confidence. The data available show a poor effect of these interventions on nutritional status, but methodological weaknesses of the studies cast serious doubts on the validity of these results. More rigorous and better designed studies are needed, as well as the establishment of agreed quality standards to guide researchers in this important area.
Consumer Response to Healthy Eating, Physical Activity and Weight-Related Recommendations: A Systematic Review
Obesity Review 2012 Mar 8 by Boylan S, Louie JC, Gill TP. From Cluster for Public Health Nutrition, Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, The University of Sydney, New South Wales, Australia.
Abstract: Strong evidence linking poor diet and lack of physical activity to risk of obesity and related chronic disease has supported the development and promotion of guidelines to improve population health. Still, obesity continues to escalate as a major health concern, and so the impact of weight-related guidelines on behaviour is unclear. The aim of this review was to examine consumer response to weight-related guidelines. A systematic literature search was performed using Medline, PsycInfo, ProQuest Central and additional searches using Google and reference lists. Of the 1,765 articles identified, 46 relevant titles were included. Most studies examined attitudes towards content, source, tailoring and comprehension of dietary guidelines. Many respondents reported that guidelines were confusing, and that simple, clear, specific, realistic, and in some cases, tailored guidelines are required. Recognition of guidelines did not signify understanding nor did perceived credibility of a source guarantee utilization of guidelines. There was a lack of studies assessing: the impact of guidelines on behaviour; responses to physical activity guidelines; responses among males and studies undertaken in developing countries. Further research is needed, in particular regarding responses to physical activity guidelines and guidelines in different populations. Communication professionals should assist health professionals in the development of accurate and effective weight-related guidelines.
Salt and Hypertension: Is Salt Dietary Reduction Worth The Effort?
American Journal of Medicine 2012 May;125(5):433-9. By Frisoli TM, Schmieder RE, Grodzicki T, Messerli FH. from St Luke’s-Roosevelt Hospital Center, New York, New York, USA.
Abstract: In numerous epidemiologic, clinical, and experimental studies, dietary sodium intake has been linked to blood pressure, and a reduction in dietary salt intake has been documented to lower blood pressure. In young subjects, salt intake has a programming effect in that blood pressure remains elevated even after a high salt intake has been reduced. Elderly subjects, African Americans, and obese patients are more sensitive to the blood pressure-lowering effects of a decreased salt intake. Depending on the baseline blood pressure and degree of salt intake reduction, systolic blood pressure can be lowered by 4 to 8 mm Hg. A greater decrease in blood pressure is achieved when a reduced salt intake is combined with other lifestyle interventions, such as adherence to Dietary Approaches to Stop Hypertension. A high salt intake has been shown to increase not only blood pressure but also the risk of stroke, left ventricular hypertrophy, and proteinuria. Adverse effects associated with salt intake reduction, unless excessive, seem to be minimal. However, data linking a decreased salt intake to a decrease in morbidity and mortality in hypertensive patients are not unanimous. Dietary salt intake reduction can delay or prevent the incidence of antihypertensive therapy, can facilitate blood pressure reduction in hypertensive patients receiving medical therapy, and may represent a simple cost-saving mediator to reduce cardiovascular morbidity and mortality.
Kevin W Chen, Ph.D., MPH is an associate professor at the Center for Integrative Medicine and Department of Psychiatry, University of Maryland School of Medicine (USA). Dr. Chen was educated in the universities of both China and the United States, and has years of experience and training in blending eastern and western perspectives, and in the practice of life-nurturing methods. As a long-time practitioner of Qigong Yang Sheng, he is one of the few scientists in the U.S. to have both hands-on knowledge of mind-body practice, and an active research career in mind-body medicine, which is funded through grants by the National Institutes of Health (NIH) and various foundations. Dr. Chen devotes his career and life to the practice of Yang Sheng, and promotion of self-healing and mind-body-spirit integration through the non-profit organization, World Institute for Self Healing (WISH) ttp://www.wishus.org