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Glycemic Index, Glycemic Load and Cancer Risk: An Updated Meta-Analysis.
Turati, F, Galeone, C, Augustin, LSA, La Vecchia, C
Nutrients. 2019;11(10)
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This 2019 meta-analysis is an update of an earlier 2015 study on the relationship between high Glycemic Index (GI) and Glycemic load (GL) diets and cancer risk. Twenty new epidemiological reports were added to the original seventy-five studies covering a total of 169,00 cancer cases. The theory is that elevated insulin levels, triggered by a high GI diet, increase bioactive chemicals which promote cancer development by inhibiting cell apoptosis and stimulating cell proliferation. This study collated cancers into 3 subgroups of hormonal cancers (breast, endometrium, ovary and prostate), digestive tract cancers (cancers, stomach, colorectum and pancreas) and other (lung, bladder and kidney). The combined results showed that the risk ratio for hormonal-related cancers and GI/GL were modestly elevated but not significant except for a possible moderate positive association between GL and endometrial cancer (RR1.12). There was a positive significant association between high GI intake and colorectal cancer risk (RR 1.20) but not with the other digestive-tract cancers. A high GI was associated with small increased risks of bladder (RR 1.25) and kidney (RR 1.16) cancers. The researchers conclude that the high number of studies and cancer types included provide high statistical power. Although the results show only moderate association this may be relevant at population level given the high incidence of cancers.
Abstract
Diets high in glycemic index (GI) and glycemic load (GL) have been related to an increased risk of selected cancers, but additional quantification is required. We updated a systematic review and meta-analysis published in 2015 to May 2019 to provide quantitative information on GI/GL and cancer risk. Relative risks (RR) and the corresponding 95 % confidence intervals (CI) for the highest versus the lowest categories of GI and GL were extracted from selected studies and pooled using random-effects models. Twenty reports (>22,000 cancer cases) have become available after January 2015, and 15 were added to the meta-analyses by cancer sites, which considered a total of 88 investigations. The five additional reports were reviewed, but not included in the meta-analyses, since data were inadequate to be pooled. For hormone-related cancers, summary RRs for the highest versus lowest GI and GL intakes were moderately increased. They ranged from 1.04 (breast) to 1.12 (endometrium) for GI and from 1.03 (prostate) to 1.22 (ovary) for GL, of borderline significance. High GI was associated with small increased risks of colorectal (summary RR for GI: 1.20, 95% CI, 1.07-1.34-GL: 1.09, 95% CI, 0.97-1.22, 19 studies), bladder (GI: 1.25, 95% CI, 1.11-1.41-GL: 1.10, 95% CI, 0.85-1.42, four studies) and kidney cancers (GI: 1.16, 95% CI, 1.02-1.32-GL: 1.14, 95% CI, 0.81-1.60, five studies). GL was not significantly related to those cancer sites. Stomach, prostate and lung cancers were not associated with GI and GL. The present analysis, based on an updated comprehensive evaluation of the epidemiological literature, indicates moderate unfavorable effects of high versus low GI on colorectal, and possibly bladder and kidney cancers, and a possible moderate positive association between GL and endometrial cancer.
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Mechanisms Underlying Metabolic Syndrome-Related Sarcopenia and Possible Therapeutic Measures.
Rubio-Ruiz, ME, Guarner-Lans, V, Pérez-Torres, I, Soto, ME
International journal of molecular sciences. 2019;20(3)
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Sarcopenia is a multifactorial process in which losses occur in both muscle mass and function. Although several studies indicate an association between sarcopenia and metabolic syndrome (MetS), the connection has not been extensively reviewed. The aim of this study is to examine the relationship between sarcopenia and MetS to better understand the mechanisms underlying disease and assess current therapeutic options. According to the existing literature, this study found insulin resistance, inflammation and obesity to be major underlying factors of MetS-related sarcopenia. Based on this information, the authors suggest the best option for managing MetS-related sarcopenia is preventative lifestyle change around diet and exercise until a consensus on a therapeutic treatment can be established.
Abstract
Although there are several reviews that report the interrelationship between sarcopenia and obesity and insulin resistance, the relation between sarcopenia and the other signs that compose the metabolic syndrome (MetS) has not been extensively revised. Here, we review the mechanisms underlying MetS-related sarcopenia and discuss the possible therapeutic measures proposed. A vicious cycle between the loss of muscle and the accumulation of intramuscular fat might be associated with MetS via a complex interplay of factors including nutritional intake, physical activity, body fat, oxidative stress, proinflammatory cytokines, insulin resistance, hormonal changes, and mitochondrial dysfunction. The enormous differences in lipid storage capacities between the two genders and elevated amounts of endogenous fat having lipotoxic effects that lead to the loss of muscle mass are discussed. The important repercussions of MetS-related sarcopenia on other illnesses that lead to increased disability, morbidity, and mortality are also addressed. Additional research is needed to better understand the pathophysiology of MetS-related sarcopenia and its consequences. Although there is currently no consensus on the treatment, lifestyle changes including diet and power exercise seem to be the best options.
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Intermittent Fasting in Cardiovascular Disorders-An Overview.
Malinowski, B, Zalewska, K, Węsierska, A, Sokołowska, MM, Socha, M, Liczner, G, Pawlak-Osińska, K, Wiciński, M
Nutrients. 2019;11(3)
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Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. IF has gained popularity in recent years with people wanting to lose weight, and it may have many long-term health benefits. In this review, the authors looked at human and animal studies using variations of IF including time restricted eating (TRE), where eating is confined within a specific window during the day (for example 8 hours eating and 16 hours fasting), and alternate day fasting (ADF), where a day of eating normally is alternated with a day of either fasting entirely, or significant calorie restriction. The authors found that IF is related to many beneficial effects on the cardiovascular system, involving atherosclerosis progression, benefits for diabetes mellitus type 2 such as improved glucose metabolism and insulin sensitivity, lowering of blood pressure, and other cardiovascular risk factors (such as lipid profile and inflammation). It is currently unclear whether the benefits of IF are solely due to weight loss or other mechanisms. The success of every type of diet depends on compliance, and IF seems to be as easy or easier to follow than more traditional diets for many people. Fasting is not recommended for people with hormonal imbalances, pregnant and breastfeeding women, and diabetics. People with eating disorders and underweight people are also not recommended to use the intermittent fasting diet. In recent years, the IF diet and its varieties have become increasingly popular. This diet not only serves to reduce body weight but seems to have other long-term health benefits. However, individuals’ current health and situation should be considered before commencing the IF diet.
Abstract
Intermittent fasting is a form of time restricted eating (typically 16 h fasting and 8 h eating), which has gained popularity in recent years and shows promise as a possible new paradigm in the approach to weight loss and the reduction of inflammation, and has many potential long term health benefits. In this review, the authors will incorporate many aspects of fasting, mainly focusing on its effects on the cardiovascular system, involving atherosclerosis progression, benefits for diabetes mellitus type 2, lowering of blood pressure, and exploring other cardiovascular risk factors (such as lipid profile and inflammation).
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Food sources of fructose-containing sugars and glycaemic control: systematic review and meta-analysis of controlled intervention studies.
Choo, VL, Viguiliouk, E, Blanco Mejia, S, Cozma, AI, Khan, TA, Ha, V, Wolever, TMS, Leiter, LA, Vuksan, V, Kendall, CWC, et al
BMJ (Clinical research ed.). 2018;363:k4644
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With increasing evidence linking fructose to metabolic disease, current dietary guidelines recommend a reduction of added free sugars, especially fructose-containing sugars from sugars-sweetened beverages (SSBs). However, it is currently unclear whether the negative impact of fructose on metabolic health is as implicative in the context of an overall dietary consumption pattern. The aim of this study was to assess the effect of different sources of fructose-containing sugars on glycaemic control in people with and without diabetes. This review analysed 155 controlled intervention studies and found that fructose-containing sugars in the form of fruit do not have a harmful effect on glycaemic control when compared to energy-matched macronutrient substitutions. Further, harmful effects on glycaemic control were found when excess energy in the form of fructose-containing sugars from SSBs were added to the diet. The authors conclude the food source of fructose-containing sugars on glycemic control is important in the conversation of metabolic health and glycaemic control. While further research is needed to assess a wider variety of food sources, public health professionals should consider the influence of food sources when developing dietary recommendations for the prevention and management of diabetes and other metabolic conditions.
Abstract
OBJECTIVE To assess the effect of different food sources of fructose-containing sugars on glycaemic control at different levels of energy control. DESIGN Systematic review and meta-analysis of controlled intervention studies. DATA SOURCES Medine, Embase, and the Cochrane Library up to 25 April 2018. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Controlled intervention studies of at least seven days' duration and assessing the effect of different food sources of fructose-containing sugars on glycaemic control in people with and without diabetes were included. Four study designs were prespecified on the basis of energy control: substitution studies (sugars in energy matched comparisons with other macronutrients), addition studies (excess energy from sugars added to diets), subtraction studies (energy from sugars subtracted from diets), and ad libitum studies (sugars freely replaced by other macronutrients without control for energy). Outcomes were glycated haemoglobin (HbA1c), fasting blood glucose, and fasting blood glucose insulin. DATA EXTRACTION AND SYNTHESIS Four independent reviewers extracted relevant data and assessed risk of bias. Data were pooled by random effects models and overall certainty of the evidence assessed by the GRADE approach (grading of recommendations assessment, development, and evaluation). RESULTS 155 study comparisons (n=5086) were included. Total fructose-containing sugars had no harmful effect on any outcome in substitution or subtraction studies, with a decrease seen in HbA1c in substitution studies (mean difference -0.22% (95% confidence interval to -0.35% to -0.08%), -25.9 mmol/mol (-27.3 to -24.4)), but a harmful effect was seen on fasting insulin in addition studies (4.68 pmol/L (1.40 to 7.96)) and ad libitum studies (7.24 pmol/L (0.47 to 14.00)). There was interaction by food source, with specific food sources showing beneficial effects (fruit and fruit juice) or harmful effects (sweetened milk and mixed sources) in substitution studies and harmful effects (sugars-sweetened beverages and fruit juice) in addition studies on at least one outcome. Most of the evidence was low quality. CONCLUSIONS Energy control and food source appear to mediate the effect of fructose-containing sugars on glycaemic control. Although most food sources of these sugars (especially fruit) do not have a harmful effect in energy matched substitutions with other macronutrients, several food sources of fructose-containing sugars (especially sugars-sweetened beverages) adding excess energy to diets have harmful effects. However, certainty in these estimates is low, and more high quality randomised controlled trials are needed. STUDY REGISTRATION Clinicaltrials.gov (NCT02716870).
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Cardio-Metabolic Benefits of Plant-Based Diets.
Kahleova, H, Levin, S, Barnard, N
Nutrients. 2017;9(8)
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Chronic disease, which includes cardiovascular disease, obesity, type 2 diabetes, hypertension, hyperlipidaemia and stroke, is the underlying cause of many health and economic burdens. There is ample evidence that proper nutrition, specifically plant-based diets (PBDs), are an effective strategy for reducing the burden of chronic disease. The aim of this narrative review is to summarise the most recent evidence on the efficacy of PBDs on various cardio-metabolic disease risk factors. This review found consistent, convincing evidence around PBDs improving body weight, glycaemic control, blood pressure and blood lipid profile, thus reducing the overall risk factors associated with chronic disease. Based on these findings, the authors conclude properly planned PBDs are an effective tool for preventing and treating cardio-metabolic disease and encourage PBDs to be recommended and promoted.
Abstract
Cardio-metabolic disease, namely ischemic heart disease, stroke, obesity, and type 2 diabetes, represent substantial health and economic burdens. Almost one half of cardio-metabolic deaths in the U.S. might be prevented through proper nutrition. Plant-based (vegetarian and vegan) diets are an effective strategy for improving nutrient intake. At the same time, they are associated with decreased all-cause mortality and decreased risk of obesity, type 2 diabetes, and coronary heart disease. Evidence suggests that plant-based diets may reduce the risk of coronary heart disease events by an estimated 40% and the risk of cerebral vascular disease events by 29%. These diets also reduce the risk of developing metabolic syndrome and type 2 diabetes by about one half. Properly planned vegetarian diets are healthful, effective for weight and glycemic control, and provide metabolic and cardiovascular benefits, including reversing atherosclerosis and decreasing blood lipids and blood pressure. The use of plant-based diets as a means of prevention and treatment of cardio-metabolic disease should be promoted through dietary guidelines and recommendations.
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Calories, carbohydrates, and cancer therapy with radiation: exploiting the five R's through dietary manipulation.
Klement, RJ, Champ, CE
Cancer metastasis reviews. 2014;33(1):217-29
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Radiation therapy is standard care for cancer patients alongside surgery and chemotherapy. However, there are still some cancers which seem to withstand this treatment. This study looks at whether calorie reduction (CR) and carbohydrate restriction can have any impact on treatment outcomes. The reason for exploring this idea comes from data showing a high level of ‘glycolysis’ (a need for sugar) in cancer cells. Calorie reduction is defined as 30-50% less calories per day achieved either by intermittent fasting or a fixed calorie regime. Carbohydrate restriction is defined as a ketogenic diet (KD); a diet which removes carbohydrate foods and sugars and focuses on high fat foods and limited protein. Both nutritional protocols have been shown to have similar metabolic effects of reducing blood sugar levels and insulin activity, and thus reducing the ability of cancer cells to communicate. The 5R principle of radiotherapy tries to exploit the differences between cancer cells and healthy tissue. The 5Rs are Repair to DNA damage, Repopulation of the tumour, Redistribution of cells, Reoxygenation of the tumour area and Radio resistance in cells which do not respond to treatment. The concern with restricting calories and carbohydrates is triggering detrimental weight loss in cancer patients, although some fat loss may be beneficial in overweight patients with hormonal cancers. Intermittent fasting seems to fit well with typical radiation treatment schedules over 2-3-month periods. Trials of ketogenic diets on healthy volunteers have shown it encourages muscle mass which is a strong predictor of survival in cancer patients. Of the two, a carbohydrate-restricted, ketogenic diet appears the most viable adjunct to radiation therapy.
Abstract
Aggressive tumors typically demonstrate a high glycolytic rate, which results in resistance to radiation therapy and cancer progression via several molecular and physiologic mechanisms. Intriguingly, many of these mechanisms utilize the same molecular pathways that are altered through calorie and/or carbohydrate restriction. Furthermore, poorer prognosis in cancer patients who display a glycolytic phenotype characterized by metabolic alterations, such as obesity and diabetes, is now well established, providing another link between metabolic pathways and cancer progression. We review the possible roles for calorie restriction (CR) and very low carbohydrate ketogenic diets (KDs) in modulating the five R's of radiotherapy to improve the therapeutic window between tumor control and normal tissue complication probability. Important mechanisms we discuss include (1) improved DNA repair in normal, but not tumor cells; (2) inhibition of tumor cell repopulation through modulation of the PI3K-Akt-mTORC1 pathway downstream of insulin and IGF1; (3) redistribution of normal cells into more radioresistant phases of the cell cycle; (4) normalization of the tumor vasculature by targeting hypoxia-inducible factor-1α downstream of the PI3K-Akt-mTOR pathway; (5) increasing the intrinsic radioresistance of normal cells through ketone bodies but decreasing that of tumor cells by targeting glycolysis. These mechanisms are discussed in the framework of animal and human studies, taking into account the commonalities and differences between CR and KDs. We conclude that CR and KDs may act synergistically with radiation therapy for the treatment of cancer patients and provide some guidelines for implementing these dietary interventions into clinical practice.