Is there a role for carbohydrate restriction in the treatment and prevention of cancer
TL;DR: The possible beneficial effects of low CHO diets on cancer prevention and treatment are addressed, with emphasis on the role of insulin and IGF1 signaling in tumorigenesis as well as altered dietary needs of cancer patients.
Abstract: Over the last years, evidence has accumulated suggesting that by systematically reducing the amount of dietary carbohydrates (CHOs) one could suppress, or at least delay, the emergence of cancer, and that proliferation of already existing tumor cells could be slowed down. This hypothesis is supported by the association between modern chronic diseases like the metabolic syndrome and the risk of developing or dying from cancer. CHOs or glucose, to which more complex carbohydrates are ultimately digested, can have direct and indirect effects on tumor cell proliferation: first, contrary to normal cells, most malignant cells depend on steady glucose availability in the blood for their energy and biomass generating demands and are not able to metabolize significant amounts of fatty acids or ketone bodies due to mitochondrial dysfunction. Second, high insulin and insulin-like growth factor (IGF)-1 levels resulting from chronic ingestion of CHO-rich Western diet meals, can directly promote tumor cell proliferation via the insulin/IGF1 signaling pathway. Third, ketone bodies that are elevated when insulin and blood glucose levels are low, have been found to negatively affect proliferation of different malignant cells in vitro or not to be usable by tumor cells for metabolic demands, and a multitude of mouse models have shown antitumorigenic properties of very low CHO ketogenic diets. In addition, many cancer patients exhibit an altered glucose metabolism characterized by insulin resistance and may profit from an increased protein and fat intake. In this review, we address the possible beneficial effects of low CHO diets on cancer prevention and treatment. Emphasis will be placed on the role of insulin and IGF1 signaling in tumorigenesis as well as altered dietary needs of cancer patients.
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TL;DR: The results suggest that the membranous expression of Glut-1 can be used as a surrogate marker in the assessing of the biological nature of benign and malignant melanocytic lesions, despite its high specificity, the sensitivity of this marker is relatively low.
Abstract: The glucose transporter-1 (Glut-1) is a cell membrane glycoprotein involved in glucose uptake. An increased expression of Glut-1 is an important cell adaptation mechanism against hypoxia. An upregulation of Glut-1 can be found in several types of malignant tumors, which are able to reprogram their metabolism from oxidative phosphorylation to aerobic glycolysis (Warburg effect). However, the data regarding melanocytic lesions is equivocal. We performed comprehensive immunohistochemical analysis of the Glut-1 expression in 225 malignant melanomas (MM) and 175 benign nevi. Only the membranous expression of Glut-1 was regarded as positive. The expression of Glut-1 (the cut-off for positivity was determined as H-score 15) was found in 69/225 malignant melanomas. The number of positive cases and the H-score of Glut-1 increased where there was a higher Breslow thickness (p < 0.00001) when comparing pT1- pT4 MM groups. All benign nevi were classified as negative. In conclusion, the membranous expression of Glut-1 is a common feature of a malignant melanoma but this type of expression is very rare in benign melanocytic nevi. Our results suggest that the membranous expression of Glut-1 can be used as a surrogate marker in the assessing of the biological nature of benign and malignant melanocytic lesions. However, despite its high specificity, the sensitivity of this marker is relatively low. Moreover, due to the fact that the increased expression of Glut-1 correlates with a shorter survival period (10-year disease free survival, recurrence free survival and metastasis free survival and MFS), it can be used as a prognostically adverse factor.
13 citations
Cites background from "Is there a role for carbohydrate re..."
...One of the characteristic features of malignant tumors is their ability to reprogramme glucose metabolism from the oxidative phosphorylation pathway to glucose aerobic glycolysis (Warburg’s effect), which represents a selective growth advantage [27, 28]....
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TL;DR: With using the paleolithic ketogenic diet the patient was able to postpone surgery for two years, and with incomplete dietary adherence, disease seemed to be stable but symptoms suggested progression for the last few months of the follow-up.
Abstract: Background: Ketogenic diets have repeatedly been suggested for the treatment of cancer. Yet, only a few case studies have been published that reported long term benefits associated with such diets. Case report: Here we present a case where rectal cancer was treated with an animal fat-meat based diet, which we refer to as the paleolithic ketogenic diet. Upon diet initiation, the patient discontinued three medicines he had been taking because of hypertension and hyperuricemia. The patient initially received 6 weeks of radiation therapy. Thereafter the patient used the diet as a stand-alone therapy for 22.5 months. The patient was not taking any medicines or dietary supplements while on the diet. During the first five month of the diet therapy the patient exhibited excellent adherence which was paralleled by improving laboratory parameters including decreasing tumor marker levels and decreasing tumor size. The patient was in a constant ketosis during the entire follow-up. From the seventh month on, however, his adherence level was fluctuating with periods of worse adherence paralleled with negative changes in laboratory parameters. Although MRI imaging showed that there was no increase in the size of the tumor, 22 months after diagnosis onset the patient reported an alteration in bowel habits and that the bloody stool had returned. Because of the emergence of these symptoms, 24 months after diagnosis onset, rectal surgery was performed. Conclusion: With using the paleolithic ketogenic diet the patient was able to postpone surgery for two years. During the first five months, when the patient was strictly adhering to the diet, the tumor regressed. Thereafter, with incomplete dietary adherence, disease seemed to be stable but symptoms suggested progression for the last few months of the follow-up. Deviations from diet rules, even those not affecting ketosis, resulted in the progression of the disease.
13 citations
Cites background from "Is there a role for carbohydrate re..."
...Carbohydrate-restricted diets have also been suggested as a promising therapeutic approach in tumors [4,5,6]....
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TL;DR: The existence of molecular links that facilitate colorectal cancer (CRC) development in the population with type 2 diabetes (T2D) is supported by substantial epidemiological evidence as discussed by the authors.
Abstract: The existence of molecular links that facilitate colorectal cancer (CRC) development in the population with type 2 diabetes (T2D) is supported by substantial epidemiological evidence. This review summarizes how the systemic, metabolic and hormonal imbalances from T2D alter CRC cell metabolism, signalling and gene expression as well as their reciprocal meshing, with an overview of CRC molecular subtypes and animal models to study the diabetes-CRC cancer links. Metabolic and growth factor checkpoints ensure a physiological cell proliferation rate compatible with limited nutrient supply. Hyperinsulinaemia and hyperleptinaemia in prediabetes and excess circulating glucose and lipids in T2D overcome formidable barriers for tumour development. Increased nutrient availability favours metabolic reprogramming, alters signalling and generates mutations and epigenetic modifications through increased reactive oxygen species and oncometabolites. The reciprocal control between metabolism and hormone signalling is lost in diabetes. Excess adipose tissue at the origin of T2D unbalances adipokine (leptin/adiponectin) secretion ratios and function and disrupts the insulin/IGF axes. Leptin/adiponectin imbalances in T2D are believed to promote proliferation and invasion of CRC cancer cells and contribute to inflammation, an important component of CRC tumourigenesis. Disruption of the insulin/IGF axes in T2D targets systemic and CRC cell metabolic reprogramming, survival and proliferation. Future research to clarify the molecular diabetes-CRC links will help to prevent CRC and reduce its incidence in the diabetic population and must guide therapeutic decisions.
12 citations
Dissertation•
28 Aug 2014
TL;DR: Predictors of response – which, in the absence of specific metabolic disorders, are unknown – would improve patient selection and may enhance understanding of how the KD exerts its antiseizure effect.
Abstract: The Ketogenic diet (KD) is an alternative treatment option for people with drug-resistant epilepsy. It can reduce seizure frequency, but it is resource-intensive and may cause adverse side effects. Predictors of response – which, in the absence of specific metabolic disorders, are unknown – would improve patient selection and may enhance understanding of how the KD exerts its antiseizure effect. This project is concerned with identifying possible genetic markers of response to the KD. DNA was extracted from capillary blood taken from individuals who were following the KD for their epilepsy, or who had done so in the past. Individuals were classed as responders if they achieved ≥50 seizure reduction. Response was classified at various follow-up points, as well as a summary of response over time. Association studies were conducted using candidate gene (KCNJ11 and BAD) sequencing, genome-wide single nucleotide polymorphism array, and whole exome sequencing data to determine whether there was an over-representation of specific gene variants in KD responders, compared to non-responders. Common variation in KCNJ11 and BAD was not significantly associated with KD response. rs12204701 reached significance in the array-based genome-wide association study including common variants, with 3-month diet response as the phenotype. No significant results were obtained when summary diet response was taken as the phenotype. Using the gene-based c-alpha test with the exome sequencing data, including all exonic and splicing variants, ANKRD36C reached significance; using a pathway-based count of case-unique alleles test, the ‘ERBB1 Internalisation’ pathway reached significance. No further significant results were obtained from the exome sequencing data when using other gene- and pathway-based tests or when variants were further filtered according to predicted functional consequence. Other genes with large differences in responder/non-responder minor or alternative allele counts are also of interest. It is unknown how these may contribute to variability in KD response. Some common themes were identified amongst the genes and pathways of significance and suggestive significance: cell cycling, apoptosis, glucose homeostasis, neurological processes and triglyceride biosynthesis. It is biologically plausible that these processes influence KD response, although it is likely that many genes play a role. A larger sample size is needed in order to improve power to detect genotypic-phenotypic associations and increase confidence in the importance of the genes of interest.
12 citations
Additional excerpts
...catabolic processes such as autophagy [1144, 1145]....
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TL;DR: Ketone body measurement is relatively inexpensive and can provide metabolic insights to help guide disease management and optimize weight loss.
Abstract: Background The ketone bodies β-hydroxybutyrate (BOHB) and acetone are generated as a byproduct of the fat metabolism process. In healthy individuals, ketone body levels are ∼0.1 mM for BOHB and ∼1 part per million for breath acetone (BrAce). These levels can increase dramatically as a consequence of a disease process or when used therapeutically for disease treatment. For example, increased ketone body concentration during weight loss is an indication of elevated fat metabolism. Ketone body measurement is relatively inexpensive and can provide metabolic insights to help guide disease management and optimize weight loss. Methods This review of the literature provides metabolic mechanisms and typical concentration ranges of ketone bodies, which can give new insights into these conditions and rationale for measuring ketone bodies. Results Diseases such as heart failure and ketoacidosis can affect caloric intake and macronutrient management, which can elevate BOHB 30-fold and BrAce 1000-fold. Other diseases associated with obesity, such as brain dysfunction, cancer, and diabetes, may cause dysfunction because of an inability to use glucose, excessive reliance on glucose, or poor insulin signaling. Elevating ketone body concentrations (e.g., nutritional ketosis) may improve these conditions by forcing utilization of ketone bodies, in place of glucose, for fuel. During weight loss, monitoring ketone body concentration can demonstrate program compliance and can be used to optimize the weight-loss plan. Conclusions The role of ketone bodies in states of pathologic and therapeutic ketosis indicates that accurate measurement and monitoring of BOHB or BrAce will likely improve disease management. Bariatric surgery is examined as a case study for monitoring both types of ketosis.
12 citations
References
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TL;DR: Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer.
51,099 citations
"Is there a role for carbohydrate re..." refers background in this paper
..., a pathological capability common to most, if not all, cancer cells [39]....
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TL;DR: The molecular pathways of this cancer-related inflammation are now being unravelled, resulting in the identification of new target molecules that could lead to improved diagnosis and treatment.
Abstract: The mediators and cellular effectors of inflammation are important constituents of the local environment of tumours. In some types of cancer, inflammatory conditions are present before a malignant change occurs. Conversely, in other types of cancer, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumours. Regardless of its origin, 'smouldering' inflammation in the tumour microenvironment has many tumour-promoting effects. It aids in the proliferation and survival of malignant cells, promotes angiogenesis and metastasis, subverts adaptive immune responses, and alters responses to hormones and chemotherapeutic agents. The molecular pathways of this cancer-related inflammation are now being unravelled, resulting in the identification of new target molecules that could lead to improved diagnosis and treatment.
9,282 citations
"Is there a role for carbohydrate re..." refers background in this paper
...Inflammation is a wellestablished driver of early tumorigenesis and accompanies most, if not all cancers [148]....
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TL;DR: In this article, the authors propose that persistent metabolism of glucose to lactate even in aerobic conditions is an adaptation to intermittent hypoxia in pre-malignant lesions, which leads to microenvironmental acidosis requiring evolution to phenotypes resistant to acid-induced cell toxicity.
Abstract: If carcinogenesis occurs by somatic evolution, then common components of the cancer phenotype result from active selection and must, therefore, confer a significant growth advantage. A near-universal property of primary and metastatic cancers is upregulation of glycolysis, resulting in increased glucose consumption, which can be observed with clinical tumour imaging. We propose that persistent metabolism of glucose to lactate even in aerobic conditions is an adaptation to intermittent hypoxia in pre-malignant lesions. However, upregulation of glycolysis leads to microenvironmental acidosis requiring evolution to phenotypes resistant to acid-induced cell toxicity. Subsequent cell populations with upregulated glycolysis and acid resistance have a powerful growth advantage, which promotes unconstrained proliferation and invasion.
4,361 citations
2,524 citations
TL;DR: Dietary restriction and reduced activity of nutrient-sensing pathways may slow aging by similar mechanisms, which have been conserved during evolution, and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.
Abstract: When the food intake of organisms such as yeast and rodents is reduced (dietary restriction), they live longer than organisms fed a normal diet. A similar effect is seen when the activity of nutrient-sensing pathways is reduced by mutations or chemical inhibitors. In rodents, both dietary restriction and decreased nutrient-sensing pathway activity can lower the incidence of age-related loss of function and disease, including tumors and neurodegeneration. Dietary restriction also increases life span and protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and in humans it causes changes that protect against these age-related pathologies. Tumors and diabetes are also uncommon in humans with mutations in the growth hormone receptor, and natural genetic variants in nutrient-sensing pathways are associated with increased human life span. Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.
2,522 citations
"Is there a role for carbohydrate re..." refers background in this paper
...As indicated in Figure 2, restriction of dietary CHOs would counteract this signalling cascade by normalizing glucose and insulin levels in subjects with metabolic syndrome, in this way acting similar to calorie restriction/fasting [61,62]....
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