Showing papers in "Current Nutrition Reports in 2012"

Gene–Lifestyle Interactions in Obesity

Abstract: Obesity is a complex multifaceted disease resulting from interactions between genetics and lifestyle. The proportion of phenotypic variance ascribed to genetic variance is 0.4 to 0.7 for obesity and recent years have seen considerable success in identifying disease-susceptibility variants. Although with the advent of genome-wide association studies the list of genetic variants predisposing to obesity has significantly increased the identified variants only explain a fraction of disease heritability. Studies of gene–environment interactions can provide more insight into the biological mechanisms involved in obesity despite the challenges associated with such designs. Epigenetic changes that affect gene function without DNA sequence modifications may be a key factor explaining interindividual differences in obesity, with both genetic and environmental factors influencing the epigenome. Disentangling the relative contributions of genetic, environmental and epigenetic marks to the establishment of obesity is a major challenge given the complex interplay between these determinants.

Recent Evidence for Colorectal Cancer Prevention Through Healthy Food, Nutrition, and Physical Activity: Implications for Recommendations

Abstract: The aim of this paper is to present results from the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Continuous Update Project on colorectal cancer and food, nutrition, and physical activity, an updated systematic literature review on evidence forming part of the 2007 WCRF/AICR Second Expert Report. Convincing evidence indicates that physical activity protects against colon cancer and that foods containing dietary fiber protect against colorectal cancer. Consumption of red meat and processed meat, ethanol from alcoholic drinks (by men and probably by women), as well as body fatness and abdominal fatness and the factors that lead to greater adult-attained height or its consequences are convincing causes of colorectal cancer. Consumption of garlic, milk, and calcium probably protects against this cancer. The updated evidence shows that food, nutrition, and physical activity have an important role in the causation and prevention of colorectal cancer.

Gene-Diet Interactions in Complex Disease: Current Findings and Relevance for Public Health.

Abstract: Rates of obesity and related complex diseases such as type 2 diabetes and cardiovascular disease have climbed sharply over the past decades, in parallel with shift from principally more active lifestyle and nutritionally dense tradition diet to sedentary lifestyle and more energy-dense, Western-pattern diet. In the past few years, advances in genotyping technology and in particular a number of large-scale genome-wide association studies have made great strides in unraveling the genetic basis of complex diseases; and the growing inventory of genetic variation is facilitating efforts to investigate gene-diet interactions. Understanding gene-diet interaction has the potential to promote diet modifications on the basis of genetic makeup. Several recent large-scale studies found reproducible evidence showing consumption of sugar sweetened beverages or dietary patterns might modulate genetic predisposition to obesity or cardiovascular disease. Analyses in randomized trials also showed that genetic markers for obesity, diabetes, or cardiovascular disease might modify the metabolic response to weight-loss diets. However, little of the knowledge about gene-diet interaction has been applied in public health practice; and opinion on how genetic testing services are offered and interpreted is still divided. This review will summarize recent findings regarding obesogenic diet, genetic susceptibility, and gene-diet interactions for obesity and related complex disorders and will discuss the potential impact of these findings on public health practice.

Selenium Supplementation and Cancer Prevention

Abstract: The essential trace element selenium has been shown to have cancer preventive potential by a converging body of epidemiologic and preclinical studies. Although randomized controlled trials suggest a benefit against liver cancer, results at other sites are not as consistent. The Nutritional Prevention of Cancer Trial provided evidence that selenium-enriched yeast can protect against total cancer incidence and the incidence of prostate, lung, and colorectal cancer. In contrast, in the Selenium and Vitamin E Cancer Prevention Trial (SELECT), selenomethionine provided no protection against prostate, lung, or colorectal cancer. Results from these trials suggest that the cancer protective effects of selenium probably depend on the baseline selenium status of the individual, chemical form of selenium utilized, gender, and genetic polymorphisms in selenoproteins or in cancer-related processes.

Gene-Diet Interactions on Colorectal Cancer Risk.

Abstract: There has been increasing interest lately in understanding how natural dietary antioxidants affect chemoprevention, and recently, there has been a merging of information about antioxidants, endogenous and exogenous reactive oxygen and nitrogen species (RONS), and inflammation. RONS normally serve the cells as second messengers to regulate many of the intracellular signaling cascades that govern multiple cellular activities. However, when the amount of RONS exceeds the cell’s ability to metabolize/eliminate them, the cell becomes stressed and acquires genetic and epigenetic aberrations and dysregulated intracellular signaling cascades. In addition, there has been a better understanding of the role of tissue inflammation in the carcinogenesis process. Herein we integrate these fields to explain where RONS arise and how natural dietary antioxidants are principally working through refurbishing pathways that use RONS as second messengers.

Impact of Diet, Body Mass Index, and Physical Activity on Cancer Survival.

Abstract: With the increase in the number of cancer patients worldwide in the coming years, the need for knowledge on the influence of lifestyle factors on cancer survival is increasing. In this paper, the current knowledge on diet, body mass index, and physical activity in relation to cancer outcome is summarized. Also, challenges are identified to be addressed to provide evidence-based recommendations for cancer patients. Studies in patients with breast, colorectal, or prostate cancer show that the influence of dietary factors on survival remains to be determined. Adiposity and a lack of physical activity, however, appear to influence cancer outcome negatively. Subsequent studies should focus on more detailed aspects of these lifestyle factors, such as body composition and dose of exercise, and on the timing with respect to diagnosis and treatment. Research should be directed toward investigating diet and physical activity simultaneously and on how changes in health behavior can be established.

Nutrigenomics and Cancer Prevention.

Abstract: Mounting evidence continues to point to dietary habits as a modifier of cancer risk and tumor behavior; although it is clear that considerable variability occurs across studies. While genetic public health messages can be developed, the use of mean values may result in underexposure to some essential and nonessential food components, yet precipitate overexposure to nutrients. Undeniably, inconsistencies in the literature may reflect variation in timing of exposures to specific dietary constituents, interactions with the food matrix, processing technologies, or the genomic variation among individuals, which can influence absorption, metabolism, and/or the molecular target. Inter-individual variability in genetics, epigenetics, transcriptomics, proteomics, metabolomics, or microbiomics can influence the magnitude and direction of response to bioactive food components, as briefly reviewed in this article. Unquestionably, understanding nutrigenomics holds promise to reveal those who will benefit most from dietary interventions plus identify any who might be placed at risk due to overexposures.

Genetic Predisposition and Taste Preference: Impact on Food Intake and Risk of Chronic Disease

Abstract: Nutritional intake can profoundly impact the development of human disease, mainly by driving the progression of obesity-related conditions such as type 2 diabetes, cardiovascular disease, and cancer. Taste perception can profoundly affect food preference and nutritional intake. Thus, human variation in taste responsiveness to certain foods may play an integral role in these health consequences by influencing nutrient assimilation. Therefore, we review here what is currently known about variation in taste perception, its genetic underpinnings, and how this variation may impact upon nutrient ingestion. We also provide a brief primer on the functional organization of the peripheral gustatory system. Elucidation of the mechanisms underpinning the association between taste perception, eating behavior, and energy regulation could be valuable in predicting who is at greater risk of becoming obese, as well as in finding novel therapeutic targets in the management and mitigation of obesity-related conditions.

Current Trends in Childhood Obesity Research

Abstract: Childhood obesity is a global health issue. To identify research trends and gaps of childhood obesity research, we reviewed MEDLINE publications from January 2011 to May 2012 and qualitatively analyzed the major domains and themes of research focus. Major domains are: measurements, obesity correlates, prevention interventions, treatment interventions, and policy issues. Key advances and innovations are highlighted within each domain. Emerging areas include the advancement of measurement methodologies that simultaneously capture individual and contextual information across time, analysis of policy problems, and the development of multilevel, community interventions. However, few effective and sustainable interventions are exemplified; some strategies are promising. Recommendations for future research includes the adoption of a systems approach that integrates individual, environmental, and policy change, the scale up and diffusion of innovations, studies of intended and unintended policy impacts, and the design and testing of effective social marketing strategies.

Dietary Pattern, Lifestyle Factors, and Cardiovascular Diseases

Abstract: Primary prevention of cardiovascular disease (CVD) is considered the most effective strategy for controlling CVD and its consequences. Modification of risk factors is an effective way to reduce CVD risk, and most risk factors can be altered with lifestyle changes and medications. Prospective studies have demonstrated that individually modified lifestyle factors (including physical activity, smoking, alcohol consumption, body mass index, and dietary factors) are associated with lower risks of coronary heart disease (CHD), heart failure (HF), and stroke, but the results are inconsistent. The association between diet and the risk of CVD is varying. Furthermore, there are not enough studies to demonstrate the joint effects of multiple modifiable lifestyle factors on the risks of CHD, HF, and stroke. This review focuses on the dietary pattern, other lifestyle factors, and the joint associations of multiple modifiable lifestyle factors with the risks of CHD, HF, and stroke and has found that healthy lifestyle factors, including healthy diet, were significantly associated with decreased risks of CHD, HF, and stroke in men and women, and the risks progressively decreased as the number of healthy lifestyle factors increased. These results also suggest that in the general population, most cases of CHD, HF, and stroke could be avoided by practicing a healthy lifestyle.

Magnesium and the Cardiometabolic Syndrome

Abstract: The cardiometabolic syndrome is a cluster of metabolic factors that increase an individual’s risk of developing cardiovascular disease and type 2 diabetes mellitus. The metabolic risk factors that cluster in the syndrome include insulin resistance, hypertension, impaired glucose tolerance, central obesity, and dyslipidemia. Other abnormalities, such as chronic proinflammatory and prothrombotic states and oxidative stress, have been added to the syndrome. Magnesium (Mg) plays a key role in regulating insulin action, glucose uptake, and vascular tone. Many experimental, clinical, and epidemiologic studies have shown a clear link between Mg status and any component included in the constellation. Increasing evidence suggests a role for Mg deficiency as a possible unifying mechanism underlying the coincidence among those apparently disparate clinical conditions clustering in the syndrome. Although the use of Mg supplements has been suggested as a potential tool in the prevention of the cardiometabolic syndrome, this needs to be demonstrated by future prospective studies.

Vitamin D and Cancer Prevention

Abstract: Vitamin D and its potential role in the prevention of cancer have received widespread attention in recent years. A broad range of potential vitamin D–related mechanisms affecting carcinogenesis have been identified. Epidemiology now provides evidence for a cancer protective role of elevated levels of serum vitamin D, particularly for colorectal cancer, and less clearly for breast cancer, while for many other cancers, including cancer of the prostate, no associations have been demonstrated. There continues to be a gap between results from observational trials assessing vitamin D status and those from randomized trials of vitamin D supplementation that cannot be resolved easily. However, whether new randomized trials on vitamin D and cancer development should be conducted in the future remains debatable.

Recent Findings on the Genetics of Obesity: Is there Public Health Relevance?

Abstract: Since initial studies investigating familial forms of obesity, genome-wide association studies (GWAS) have been tremendously successful at detecting replicable associations between common genetic variation and measures of fat mass and obesity. The contributory variants found by this approach are limited, as one might expect, in terms of effect size and appear to offer little in terms of direct clinical applicability. However, can these variants with established associations be of value? This review will revisit how common genetic variation reliably associated with measures of fat mass and obesity can inform etiological understanding, improve knowledge of genetic architecture, and enable applied epidemiological analyses. With the discovery of additional body mass index-associated loci and the further functional characterization of identified variants, attempts can be made to better understand and causally analyze the genetic, biological, and environmental pathways to effect involved in obesity and its related comorbidities.

Gene–Diet Interactions in Cardiovascular Disease

Abstract: Cardiovascular disease (CVD), the leading cause of mortality worldwide, results from a complex interplay between genetic and environmental factors. Genetic studies identified genetic variants providing insights into the pathogenesis and treatment of the disease. However, the mechanisms linking the genotypic and phenotypic expression remain to be elucidated. Gene–diet interaction studies attempt to elucidate how a modifiable factor interacts with the genetic background. The knowledge gained thus far confers to small increments of CVD risk and cannot explain the molecular mechanisms of the disease. Epigenetic studies attempt to elucidate the molecular pathways affected by an environmental stimulus, such as dietary exposure. The epigenomic changes and their link to gene–diet interactions remain a challenging area for research. Understanding the complex interplay among the epigenome, genome, and dietary exposure should lead to accurate prediction, prevention, or treatment of the disease.

Calcium and Vitamin D Intake Interactions with Genetic Variants on Bone Phenotype

Abstract: The notion that environmental factors interact with genetic variants to affect phenotypes associated with complex diseases has arisen since the early days of genetic research. Among the environmental factors, nutrition holds a strong and permanent position, as it is a factor present throughout the life span. Calcium and vitamin D are the most important nutrients with regard to the development and health of the skeleton and have been associated with a variety of bone metabolic diseases (eg, osteoporosis). Multiple interactions between these two nutrients and genetic variants have been identified in the genetic research on bone phenotypes. A summary of these interactions is presented in this review. Furthermore, some ideas for the improvement of the studies in this field are also discussed within the current framework of the genetic research into bone phenotypes.

Gene–Diet Interactions and Obesity Indices

Abstract: Obesity and overweight status is growing rapidly worldwide. Although there have been enormous advances in explaining the genetic basis of obesity in recent years, the pathways that lead to a high body weight are still not fully understood. Interactions between genetic and environmental factors, including nutrient exposures and dietary behaviors, can influence the development of obesity. Specifically, genes play a decisive role under the permissive circumstances of an obesogenic environment (increase in energy intake with a decrease in physical activity). Given the many factors that influence obesity, as well as the dynamic nature of this health problem (weight gain, weight loss, weight maintenance, variability in body composition), genomic tools have been used to evaluate all possible contributions of genes to the obesity problem. In this report, we present recently discovered gene–diet interaction studies in human obesity. Although existing literature in this specific area is fairly limited, various investigations utilizing large cohorts corroborate the potential for personalized interventions that take into account genetic patterns.

Differential Association of Low-Fat and Whole-Fat Dairy Products with Blood Pressure and Incidence of Hypertension

Abstract: We summarized existing evidence stemming from laboratory, clinical, and epidemiological studies regarding the differential association between low-fat or whole-fat dairy products and blood pressure control. We identified seven, large, prospective cohorts and one randomized trial that addressed the differential effect of low-fat versus whole-fat dairy products on blood pressure control or on the incidence of hypertension. An inverse association between low-fat dairy consumption and the risk of hypertension was found in most studies, whereas no risk reduction was observed for whole-fat dairy products. Several mechanisms might account for the blood-pressure-lowering effect of dairy products. The observed differential association may be attributable to the detrimental effect of saturated fat. In conclusion, low-fat dairy products but not whole-fat dairy products may contribute to improve blood pressure control and to reduce the incidence of hypertension.

Gene–Diet Interactions on Lipid Levels: Current Knowledge in the Era of Genome-Wide Association Studies

Abstract: Plasma lipids are important risk factors for cardiovascular disease. Both genetic factors and diet are known to regulate lipid levels, and there has been a longstanding interest in how genes may interact with diet to modulate changes in lipid levels. Genome-wide association studies have recently identified the genes most strongly associated with variation in lipids within a population. In this paper, the current knowledge on gene–diet interactions to regulate lipid levels is discussed in light of these studies. Future genome-wide studies are required that specifically identify genes that are important modulators of lipid levels in response to dietary change. Some methodologic challenges inherent in these studies are discussed.

Empirically Derived Dietary Patterns and Hypertension

Abstract: The association between dietary patterns and hypertension or systolic blood pressure/diastolic blood pressure was described in 27 papers identified between January 2008 and December 2011. The majority were cross-sectional studies (with only two cohort studies). Most of the empirically derived dietary pattern studies in the literature have used factor analysis methods based on dietary data from food frequency questionnaires. There are six studies using national representative samples. The majority of the studies did not assess intake of salt. The difference in salt intake by dietary patterns is not known. “Western,” “meat and alcohol,” and “processed meat” dietary patterns are positively associated either categorically with hypertension or continuously with blood pressure in most studies. While a “vegetable”-rich food pattern is inversely related to hypertension in Western countries, the traditional Asian vegetable-rich food pattern seems not to be protective against hypertension in Asian populations. Posterior dietary pattern approaches can provide useful information in developing dietary guidelines. Further research is needed in this field.

Plant Oils and Cardiometabolic Risk Factors: The Role of Genetics.

Abstract: More than 25 years have passed since Ancel Keys and others observed that high intake of monounsaturated fatty acids, especially as supplied by plants (eg, olive oil) was associated with lower cardiovascular and overall mortality. About 15 years later, advances in genotyping technologies began to facilitate widespread study of relationships between dietary fats and genetic variants, illuminating the role of genetic variation in modulating human responses to fatty acids. More recently, microarray technologies evaluate the ways in which minor, bioactive compounds in plant oils (including olive, thyme, lemongrass, clove, eucalyptus, and others) alter gene expression to mediate anti-inflammatory and antioxidant effects. Results from a range of diverse technologies and approaches are coalescing to improve understanding of the role of the genome in shaping our responses to plant oils, and to clarify the genetic mechanisms underlying the cardioprotective benefits we derive from a wide range of plant oil constituents.

Sugar-Sweetened Beverages and Cardiovascular Disease

Abstract: During the past several decades, consumption of sugar-sweetened beverages (SSBs) has increased dramatically worldwide, contributing to the significant rise in consumption of total energy and added sugars. The health impact of current high consumption of SSBs has attracted scientific and public concerns. We have reviewed the studies published in 2010 and 2011 examining the relationship between consumption of SSBs and risk of cardiovascular disease. This review focuses on human studies, including cross-sectional studies, prospective cohorts, and randomized controlled trials, of relatively long duration (>3 weeks). The purpose of this review is to provide insights for future research and public health recommendations.

Nutrition, Genetics, and Cardiovascular Disease

Abstract: Cardiovascular disease (CVD) is the leading cause of death worldwide. Risk of CVD is determined by genetic and environmental factors. Numerous dietary factors have been linked to CVD beyond the conventional risk factors. In the past few years, genome-wide association studies have also identified more than 30 genomic loci that determine the susceptibility to cardiovascular events. Genetic background may interact with habitual dietary compositions in predisposition to CVD. In this context, large-scale studies of gene–diet interaction in prospective cohorts or randomized intervention trials have emerged to integrate genetic and dietary risk factors in predicting cardiovascular risk. The use of genetic variants to estimate a causal effect between dietary factors and CVD, namely mendelian randomization analysis, has also been considered in the nutritional epidemiology field. The purpose of this review is to present recent advances in research into dietary and genetic risk factors, gene–diet interactions, and mendelian randomization with regard to CVD risk.

Translating Findings from Lifestyle Intervention Trials of Cardiovascular Disease and Diabetes to the Primary Care Setting

Abstract: Preventing or delaying type 2 diabetes and cardiovascular disease is a key public health issue. Large, randomized, clinical trials have shown that intensive lifestyle interventions can be used to prevent or delay type 2 diabetes and to improve cardiovascular disease risk factors, but the key question that remains is how to best translate the results from these large, clinical trials into interventions that can be effectively delivered in primary care and community-based settings. Several effective approaches have been identified and tested. New research examining specific physical activity or dietary behaviors also has identified new behavioral targets for interventions.

The Role of Diet in Cancer Development and Prevention

Abstract: The World Cancer Research Fund/American Institute for Cancer Research Report on the role of diet in cancer development was published in 2007 and provides the best evidence to date on the subject. This review highlights some recent findings that add to our understanding or raise some questions. The evidence is convincing that body fatness increases cancer risk, including postmenopausal breast cancer; however, recent data indicate that the relationship is heterogeneous by subtype of breast cancer. High plasma vitamin D levels were previously thought to reduce cancer risk, and although recent evidence supports this association for some cancer sites, it also provides evidence of an increased risk of some rarer cancers, including pancreatic and esophageal cancer. Research that adds to our understanding of the association between colorectal cancer risk, fruit and vegetable intake, and also folate and colorectal cancer risk during time periods before and after folic acid fortification is also highlighted.

Vitamin D and Cardiometabolic Disease: From Observation to Intervention

Abstract: Vitamin D deficiency has become a major public health problem worldwide due to its increasing prevalence and potential health risks. There is growing evidence from experimental studies to suggest that vitamin D may influence risk of cardiometabolic disease through multiple pathways, including inhibition of the release of proinflammatory cytokines; regulation of the renin-angiotensin system; and favorable effects on lipids, blood pressure, insulin secretion and action, and thrombosis. Human observational data, primarily from cross-sectional studies, have shown that low dietary vitamin D intake or vitamin D levels are inversely related to various cardiometabolic risk factors. Prospective studies have suggested the relationship between low 25(OH)D and increased risk of cardiometabolic disease, including hypertension, type 2 diabetes, and cardiovascular disease. Evidence from small randomized trials and post-hoc analyses of large clinical trials for the effect of vitamin D supplements on cardiometabolic risk factors, however, remains inconsistent. This article aims to summarize epidemiologic data on the relationship between vitamin D and major cardiometabolic disease and highlight the challenges in translating observational evidence to future intervention studies.

Omega-3 Fatty Acids and Cardiovascular Disease Prevention

Abstract: Observational studies and early clinical trials indicated that long-chain n-3 fatty acids have a role in prevention of coronary heart disease, specifically fatal coronary heart disease. Results of recent trials have been inconsistent, although the study designs, patient populations, and n-3 doses have been quite different. Some studies have called into question whether there is any benefit from n-3 fatty acid therapy in patients who are receiving guideline-based treatment since their coronary event. Other recent trials suggest that certain patient subgroups, specifically those with diabetes or metabolic syndrome, may derive a significant benefit. Also, the only clinical trial to show a reduction in nonfatal coronary events used a higher n-3 fatty acid dose than used in the other studies, which raises the question of whether more is better for certain clinical outcomes. Only further research can resolve these questions.

Diet, Nutrients, and the Prevention of Hypertension

Abstract: A large part of blood pressure variation among individuals cannot be explained by known nutritional and dietary factors, and thus, many studies are in progress We reviewed recent observational and interventional studies investigating the relationship of dietary and nutritional factors to blood pressure in human populations During the past few years, a cross-sectional study of large-scale international populations, the INTERMAP (International Study of Macro/Micronutrients and Blood Pressure), reported the favorable effects of several nutrients, including minerals (phosphorus, calcium, magnesium, and non-heme iron), glutamic acid, n-6 and n-3 polyunsaturated fatty acids, and starch, and reduced intake of cholesterol, glucose, and fructose Observational and interventional studies also showed new evidence suggesting unfavorable effects resulting from higher intakes of red meat, fructose, and sugar-sweetened beverages, and favorable effects resulting from higher intake of lactotripeptides and polyphenol-rich dark chocolate For the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, further evidence on blood pressure–lowering effects and other favorable outcomes has accumulated These new findings should be established by further studies for the future update of dietary guidelines to prevent and manage hypertension

Obesity: Underlying Mechanisms and the Evolving Influence of Diet

Abstract: Obesity is determined by both genetic and environmental factors. Since 2007, 52 genes have been associated with obesity and obesity-related measurements in genome-wide association studies (GWAS), among these the fat and obesity-associated gene (FTO). Despite the success in identifying genes predisposing to obesity, these GWAS hits only account for approximately about 5 % of the estimated obesity heritability and do not predict who will become obese and who will not. The missing heritability might be accounted for by gene-gene and gene-environment interactions. Most consistently, physical activity has been shown to attenuate the effect of FTO on obesity. Several studies have examined gene-diet interactions in relation to obesity, but only a few suggestive interactions have been identified. This is most probably due to small effect sizes of the interactions and thereby a demand for large samples sizes and accurate measurements of exposures and outcomes. In addition to SNPs, epigenetic changes have been suggested to account for some of the missing heritability, and epigenetic changes have been shown to be induced by dietary intake of mothers, in utero conditions, and early nutrition and can lead to increased risk of developing obesity. Recently, the intestinal microbiome, the collected genome of the bacteria, also has been associated with obesity and with specific dietary profiles. The underlying mechanisms determining the susceptibility to obesity do not only include the genome but also the epigenome and the microbiome that can be modified by diet, and by genotype, adding to the complexity of determining the contributors to obesity.

The Role of Energy Balance in Cancer Prevention

Abstract: Nearly two thirds of American adults are overweight or obese, placing them at increased risk of obesity-related chronic diseases, including cancer. Although it has been known for quite some time that obesity increases initial risk of breast, colon, and endometrial cancer, new data implicate obesity as a risk factor for ovarian and thyroid cancers. In addition, recent evidence shows that obesity is associated with poor survival from most cancers. Obesity influences several biological pathways, including those related to glucose homeostasis, insulin-like growth factor signaling, and inflammation. Dysregulation of these pathways in obesity may provide the biological link between obesity and carcinogenesis.