Scientific Literature on Fasting and Health Outcomes
Compiled by Kevin W Chen, Ph.D. MPH
A Periodic Diet that Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Health-span. Cell Metab. 2015;22(1):86-99. By Brandhorst S, Choi IY, Wei M, et al.
Prolonged fasting (PF) promotes stress resistance, but its effects on longevity are poorly understood. We show that alternating PF and nutrient-rich medium extended yeast lifespan independently of established pro-longevity genes. In mice, 4 days of a diet that mimics fasting (FMD), developed to minimize the burden of PF, decreased the size of multiple organs/systems, an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration. Bi-monthly FMD cycles started at middle age extended longevity, lowered visceral fat, reduced cancer incidence and skin lesions, rejuvenated the immune system, and retarded bone mineral density loss. In old mice, FMD cycles promoted hippocampal neurogenesis, lowered IGF-1 levels and PKA activity, elevated NeuroD1, and improved cognitive performance. In a pilot clinical trial, three FMD cycles decreased risk factors/biomarkers for aging, diabetes, cardiovascular disease, and cancer without major adverse effects, providing support for the use of FMDs to promote healthspan.
Possible metabolic impact of Ramadan fasting in healthy men. Turk J Med Sci. 2014;44(6):1010-20. By Vardarli MC, Hammes HP, Vardarli İ.
BACKGROUND/AIM: Insulin sensitivity and β-cell function during Ramadan fasting in healthy male subjects have not been investigated so far. We assessed the changes of these and other metabolic parameters to judge the potential metabolic benefits of Ramadan fasting.
MATERIALS AND METHODS: Twenty-four healthy males of Turkish origin living in Germany, with normal glucose tolerance, participated in this study during Ramadan of 2009; 19 who completed fasting were analyzed. Blood was drawn at sunset after a period of fasting lasting approximately 15 h on days 0, 16, and 30 of Ramadan, as well as 7 and 28 days later. Insulin sensitivity (Homeostasis Model Assessment, HOMA), β-cell function, and other parameters were assessed.
RESULTS: Ramadan fasting was associated with a significant reduction (-) or increment (+) for the following variables: insulin sensitivity (-20%; P = 0.04), β-cell function (+10%; P = 0.049), high-density lipoprotein cholesterol (-23%; P = 0.0003), low-density lipoprotein cholesterol (+14%; P = 0.007), nonesterified fatty acids (-62%; P < 0.0001), resistin (-20%; P = 0.01), adiponectin (+16%; P = 0.003), and glucagon (-21%; P = 0.01). C-peptide, insulin, leptin, triglyceride, and very low-density lipoprotein cholesterol concentrations were not significantly changed.
CONCLUSION: Ramadan fasting is associated with transiently impaired insulin sensitivity, compensated for by an increased β-cell function. However, the pattern of insulin resistance-mediating adipocytokines suggests a potentially beneficial metabolic effect of Ramadan fasting.
Is Ramadan fasting related to health outcomes? A review on the related evidence. J Res Med Sci. 2014 Oct;19(10):987-92. By Rouhani MH, Azadbakht L.
BACKGROUND: Fasting during Ramadan is an Islamic rule. Although previous review studies have assessed the impact of Ramadan on cardiovascular risk factors, athlete performance, diabetes and transplantation, in this study we have appraised some on these reviews by focusing on limitations and also, we have reviewed more recently published study and several recent studies, which are not reviewed till now.
MATERIALS AND METHODS: In this article, we reviewed recently conducted studies in regarding the impact of Ramadan fasting on weight, lipid profile, diabetes, immune system and gestation. MEDLINE (http://www.pubmed.com) was searched by using “Ramadan” as keyword and the most recent articles in mentioned topics since 2009 until February 2014 were selected.
RESULTS: Although weight has been decreased during Ramadan in the most studies, weight regain is prevalent during the following months. Meta-analysis of pre-Ramadan lipid profile in comparison to post-Ramadan values had been showed that total cholesterol and triglyceride were decreased in men and high-density lipoprotein was increased among women. In regarding diabetes and fasting, diabetic patients should be aware that medical, nutritional and physical activity consulting is necessary for individuals with diabetes who want to fast during Ramadan. Although published studies show that Ramadan fasting had no serious adverse effect on offspring, it is strongly recommended that pregnant women avoid fasting because of the limitations of studies. The effect of fasting during Ramadan on the immune system is favorable. Ramadan fasting has no impact on kidney function and urine component.
CONCLUSION: Studies showed that Ramadan fasting has health protective effects. More precise studies should be conducted for more reliable conclusion.
Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr. 2015 Aug;102(2):464-70. By Horne BD, Muhlestein JB, Anderson JL.
BACKGROUND: Intermittent fasting, alternate-day fasting, and other forms of periodic caloric desistance are gaining popularity in the lay press and among animal research scientists. Whether clinical evidence exists for or is strong enough to support the use of such dietary regimens as health interventions is unclear.
OBJECTIVE: This review sought to identify rigorous, clinically relevant research studies that provide high-quality evidence that therapeutic fasting regimens are clinically beneficial to humans.
DESIGN: A systematic review of the published literature through January 2015 was performed by using sensitive search strategies to identify randomized controlled clinical trials that evaluated the effects of fasting on either clinically relevant surrogate outcomes (e.g., weight, cholesterol) or actual clinical event endpoints [e.g., diabetes, coronary artery disease (CAD)] and any other studies that evaluated the effects of fasting on clinical event outcomes.
RESULTS: Three randomized controlled clinical trials of fasting in humans were identified, and the results were published in 5 articles, all of which evaluated the effects of fasting on surrogate outcomes. Improvements in weight and other risk-related outcomes were found in the 3 trials. Two observational clinical outcomes studies in humans were found in which fasting was associated with a lower prevalence of CAD or diabetes diagnosis. No randomized controlled trials of fasting for clinical outcomes were identified.
CONCLUSIONS: Clinical research studies of fasting with robust designs and high levels of clinical evidence are sparse in the literature. Whereas the few randomized controlled trials and observational clinical outcomes studies support the existence of a health benefit from fasting, substantial further research in humans is needed before the use of fasting as a health intervention can be recommended.
Fasting enhances TRAIL-mediated liver natural killer cell activity via HSP70 upregulation. PLoS One. 2014 Oct 30;9(10):e110748. By Dang VT, Tanabe K, Tanaka Y, et al.
Abstract: Acute starvation, which is frequently observed in clinical practice, sometimes augments the cytolytic activity of natural killer cells against neoplastic cells. In this study, we investigated the molecular mechanisms underlying the enhancement of natural killer cell function by fasting in mice. The total number of liver resident natural killer cells in a unit weight of liver tissue obtained from C57BL/6J mice did not change after a 3-day fast, while the proportions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)+ and CD69+ natural killer cells were significantly elevated (n = 7, p <0.01), as determined by flow cytometric analysis. Furthermore, we found that TRAIL- natural killer cells that were adoptively transferred into Rag-2-/- γ chain-/- mice could convert into TRAIL+ natural killer cells in fasted mice at a higher proportion than in fed mice. Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting. Since these fasted mice highly expressed heat shock protein 70 (n = 7, p <0.05) in liver tissues, as determined by western blot, the role of this protein in natural killer cell activation was investigated. Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05). In addition, HSP70 neutralization by intraperitoneally injecting an anti- heat shock protein 70 monoclonal antibody into mice prior to fasting led to the downregulation of TRAIL expression (n = 6, p <0.05). These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.
Prolonged fasting/refeeding promotes hematopoietic stem cell regeneration and rejuvenation. Rejuvenation Res. 2014 Aug;17(4):385-9. By Mendelsohn AR, Larrick JW.
The sensitivity of hematopoietic stem cells (HSCs) to toxic effects of cancer chemotherapy is one of the major roadblocks in cancer therapy. Moreover, the loss of HSC function in the elderly (“immunosenescence”) is a major source of morbidity and mortality. Until recently, it was believed that HSCs were irreversibly damaged by the aging process. Recent work in mice shows that cycles of prolonged fasting (PF) of greater than 72 hr followed by refeeding can protect HSCs from the toxicity associated with chemotherapy and stimulate the proliferation of and rejuvenate old HSCs. A preliminary phase I trial in humans suggests that PF may confer benefit to people undergoing chemotherapy. These effects are at least partially mediated by lowered insulin-like growth factor-1 levels in the blood and stem cell microenvironment, which leads to lowered protein kinase A (PKA) activity. Reducing PKA levels or activity can replicate at least some of the effects of PF on HSCs. Shorter periods of fasting were not effective. PF represents a potentially profound, low-tech means to enhance cancer treatment and reverse aging of the immune system in the elderly. Because PF is likely to be stressful to the old and fragile, the development of PF mimetics may be warranted.
Evidence of mononuclear cell preactivation in the fasting state in polycystic ovary syndrome. Am J Obstet Gynecol. 2014 Dec;211(6):635.e1-7. By González F, Kirwan JP, Rote NS, Minium J.
OBJECTIVE: We evaluated mononuclear cell (MNC) preactivation in women with polycystic ovary syndrome (PCOS) by examining the effect of in vitro lipopolysaccharide (LPS) exposure on cytokine release in the fasting state.
STUDY DESIGN: Twenty women with PCOS (10 lean, 10 obese) and 20 weight-matched controls (10 lean, 10 obese) volunteered for study participation. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release was measured from mononuclear cells isolated from fasting blood samples and cultured in the presence and absence of LPS. Plasma IL-6 was measured from the same fasting blood samples. Insulin sensitivity was derived from an oral glucose tolerance test using the Matsuda index, and truncal fat was measured by dual-energy x-ray absorptiometry.
RESULTS: The percent change from baseline in TNF-α and IL-6 release from MNC following LPS exposure was increased (P < .04) in lean and obese women with PCOS and obese controls compared with lean controls. Plasma IL-6 was increased (P < .02) in obese women with PCOS compared with lean women with PCOS, which in turn was increased (P < .02) compared with lean controls. The MNC-derived TNF-α and IL-6 responses from MNCs were negatively correlated with insulin sensitivity (P < .03) and positively correlated with testosterone (P < .03) and androstenedione (P < .006) for the combined groups. Plasma IL-6 was positively correlated with percentage truncal fat (P < .008).
CONCLUSION: In PCOS, increased cytokine release from MNCs following LPS exposure in the fasting state reveals the presence of MNC preactivation. Importantly, this phenomenon is independent of obesity and may contribute to the development of insulin resistance and hyperandrogenism in PCOS. In contrast, the source of plasma IL-6 elevations in PCOS may be excess adiposity.
Prolonged fasting reduces IGF-1/PKA to promote hematopoietic-stem-cell-based regeneration and reverse immunosuppression. Cell Stem Cell. 2014 Jun 5;14(6):810-23. By Cheng CW, Adams GB, Perin L, et al. from University of South California.
ABSTRACT: Immune system defects are at the center of aging and a range of diseases. Here, we show that prolonged fasting reduces circulating IGF-1 levels and PKA activity in various cell populations, leading to signal transduction changes in long-term hematopoietic stem cells (LT-HSCs) and niche cells that promote stress resistance, self-renewal, and lineage-balanced regeneration. Multiple cycles of fasting abated the immunosuppression and mortality caused by chemotherapy and reversed age-dependent myeloid-bias in mice, in agreement with preliminary data on the protection of lymphocytes from chemotoxicity in fasting patients. The proregenerative effects of fasting on stem cells were recapitulated by deficiencies in either IGF-1 or PKA and blunted by exogenous IGF-1. These findings link the reduced levels of IGF-1 caused by fasting to PKA signaling and establish their crucial role in regulating hematopoietic stem cell protection, self-renewal, and regeneration.
Effects of Delayed Enteral Nutrition on Inflammatory Responses and Immune Function Competence in Critically Ill Patients with Prolonged Fasting. Hepatogastroenterology. 2014 May;61(131):606-12. By Xi F, Li N, Geng Y, Gao T, et al.
Although different studies suggest that early enteral nutrition (EEN) has benefits in reducing infectious complications, there is no data that addresses whether delayed enteral nutrition (EN) is detrimental and if it may have effects on inflammatory responses and immune function. Forty-five critically ill patients with long fasting were randomly allocated in two groups according to the type of nutritional support. The first group included patients assuming a standard enteral nutrition (EN, n = 22) and the second group assuming a parenteral nutrition (PN, n = 23). The daily nutritional amount was 25 kcal (105 kJ)/kg for all patients. The inflammatory markers white blood cells (WBC), C-reactive protein (CRP), TNF-α, IL-1-β, IL-6, IL-4, IL- 10 and the immune T-lymphocyte sub-populations CD3+, CD4+, CD8+, and HLA-DR+ were evaluated at day 1, and after 2, 3 and 7 days. IL-4, IL-10, CD3+, CD4+, CD8+ and the CD4+/CD8+ ratio were not statistically different between the two groups. WBC and TNF-α in EN patients were higher than those in PN after 3 and 7 days (P < 0.05). CRP and IL-6 levels were higher in EN patients than those assuming a PN after 2 and 3 days (P < 0.05). HLA-DR levels in patients assuming an EN were found higher than those in PN at day 7 (P < 0.05). Delayed EN for critically ill patients with long-term fasting increased systemic inflammatory responses, whereas EN could modify immune function, therefore reducing hospital stay and costs.
Intermittent fasting promotes bacterial clearance and intestinal IgA production in Salmonella typhimurium-infected mice. Scand J Immunol. 2014 May;79(5):315-24. By Godínez-Victoria M, Campos-Rodriguez R, Rivera-Aguilar V, et al.
The impact of intermittent fasting versus ad libitum feeding during Salmonella typhimurium infection was evaluated in terms of duodenum IgA levels, bacterial clearance and intestinal and extra-intestinal infection susceptibility. Mice that were intermittently fasted for 12 weeks or fed ad libitum were infected with S. typhimurium and assessed at 7 and 14 days post-infection. Next, we evaluated bacterial load in the faeces, Peyer’s patches, spleen and liver by plate counting, as well as total and specific intestinal IgA and plasmatic corticosterone levels (by immunoenzymatic assay) and lamina propria IgA levels in plasma cells (by cytofluorometry). Polymeric immunoglobulin receptor, α- and J-chains, Pax-5 factor, pro-inflammatory cytokine (tumour necrosis factor-α and interferon-γ) and anti-inflammatory cytokine (transforming growth factor-β) mRNA levels were assessed in mucosal and liver samples (by real-time PCR). Compared with the infected ad libitum mice, the intermittently fasted infected animals had (1) lower intestinal and systemic bacterial loads; (2) higher SIgA and IgA plasma cell levels; (3) higher mRNA expression of most intestinal parameters; and (4) increased or decreased corticosterone levels on day 7 and 14 post-infection, respectively. No contribution of liver IgA was observed at the intestinal level. Apparently, the changes following metabolic stress induced by intermittent fasting during food deprivation days increased the resistance to S. typhimurium infection by triggering intestinal IgA production and presumably, pathogen elimination by phagocytic inflammatory cells.
Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow. PLoS One. 2014 Feb 4;9(2):e87772. By Shushimita S, de Bruijn MJ, de Bruin RW, IJzermans JN, Hendriks RW, Dor FJ.
Dietary restriction (DR) delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many “neuronal and surgery related damaging phenomena” such as Parkinson’s disease and ischemia-reperfusion injury. The exact mechanism behind this phenomenon has not yet been elucidated. Its anti-inflammatory actions prompted us to thoroughly investigate the consequences of DR and fasting on B and T cell compartments in primary and secondary lymphoid organs of male C57Bl/6 mice. In BM we found that DR and fasting cause a decrease in the total B cell population and arrest early B cell development, while increasing the number of recirculating mature B cells. In the fasting group, a significant reduction in peripheral B cell counts was observed in both spleen and mesenteric lymph nodes (mLN). Thymopoiesis was arrested significantly at double negative DN2 stage due to fasting, whereas DR resulted in a partial arrest of thymocyte development at the DN4 stage. Mature CD3(+) T cell populations were increased in BM and decreased in both spleen and mLN. Thus, DR arrests B cell development in the BM but increases the number of recirculating mature B cells. DR also arrests maturation of T cells in thymus, resulting in depletion of mature T cells from spleen and mLN while recruiting them to the BM. The functional relevance in relation to protection against organ damage needs to be determined.
Skeletal actions of fasting-induced adipose factor (FIAF). Endocrinology. 2013 Dec;154(12):4685-94. By Lin JM, Naot D, Watson M, et al.
Several adipokines are known to influence skeletal metabolism. Fasting-induced adipose factor (FIAF) is an adipokine that gives rise to 2 further peptides in vivo, the N-terminal coiled-coil domain (FIAF(CCD)) and C-terminal fibrinogen-like domain (FIAF(FLD)). The skeletal action of these peptides is still uncertain. Our results show that FIAF(CCD) is a potent inhibitor of osteoclastogenesis and function, as seen in mouse bone marrow and RAW264.7 cell cultures, and in a resorption assay using isolated primary mature osteoclasts. The inhibitory effects at 500 ng/mL were approximately 90%, 50% and 90%, respectively, in these assays. FIAF(CCD) also stimulated osteoblast mitogenesis by approximately 30% at this concentration. In comparison, FIAF(FLD) was only active in decreasing osteoblast mitogenesis, and intact FIAF had no effect in any of these assays. In murine bone marrow cultures, FIAF(CCD) reduced the expression of macrophage colony-stimulating factor (M-CSF), nuclear factor of activated T-cells c1 (NFATc1) and dendritic cell-specific transmembrane protein (DC-STAMP), and to lesser extent suppressed the expression of connective tissue growth factor (CTGF). FIAF(CCD) also decreased expression of M-CSF and CTGF in stromal/osteoblastic ST2 cells. Its effect on receptor activator of nuclear factor κB (RANKL) and osteoprotegerin expression in bone marrow was not consistent with its inhibitory action on osteoclastogenesis, but it decreased RANKL expression in ST2 cells. In RAW264.7 cell cultures, FIAF(CCD) significantly reduced the expression of NFATc1 and DC-STAMP. In conclusion, FIAF(CCD) inhibits osteoclast differentiation and function in vitro and decreases expression of genes encoding key osteoclastogenic factors such as M-CSF, CTGF, NFATc1, and DC-STAMP. FIAF(CCD)’s action on osteoclasts may be independent of the RANKL/osteoprotegerin pathway. These results suggest a novel mechanism by which adipose tissue may regulate bone resorption and skeletal health.
Fasting abbreviation among patients submitted to oncologic surgery: systematic review. Arq Bras Cir Dig. 2015;28(1):70-3. By Pinto Ados S, Grigoletti SS, Marcadenti A.
INTRODUCTION: The abbreviation of perioperative fasting among candidates to elective surgery have been associated with shorter hospital stay and decreased postoperative complications.
OBJECTIVE: To conduct a systematic review from randomized controlled trials to detect whether the abbreviation of fasting is beneficial to patients undergoing cancer surgery compared to traditional fasting protocols.
METHOD: A literature search was performed in electronic databases: MEDLINE (PubMed), SciELO, EMBASE and Cochrane, without time restriction. Were used the descriptors: “preoperative fasting”, “cancer”, “diet restriction” and “perioperative period”. Randomized trials were included in adults of both sexes, with diagnosis of cancer. Exclusion criteria were: use of parenteral nutrition and publications in duplicate. All analyzes, selections and data extraction were done blinded manner by independent evaluators.
RESULTS: Four studies were included, with a total of 150 patients, 128 with colorectal cancer and 22 gastric cancer. The articles were published from 2006 to 2013. The main outcome measures were heterogeneous, which impaired the unification of the results by means of meta-analysis. Compared to traditional protocols, patients undergoing fasting abbreviation with the administration of fluids containing carbohydrates had improvements in glycemic parameters (fasting glucose and insulin resistance), inflammatory markers (interleukin 6 and 10) and indicators of malnutrition (grip strength hand and CRP/albumin ratio), and shorter hospital stay. The methodological quality of the reviewed articles, however, suggests that the results should be interpreted with caution.
CONCLUSION: The abbreviation of perioperative fasting in patients with neoplasm appears to be beneficial.
Fasting therapy for treating and preventing disease – current state of evidence. Forsch Komplementmed. 2013;20(6):444-53. By Michalsen A, Li C.
Periods of deliberate fasting with restriction of solid food intake are practiced worldwide, mostly based on traditional, cultural or religious reasons. There is large empirical and observational evidence that medically supervised modified fasting (fasting cure, 200-500 kcal nutritional intake per day) with periods of 7-21 days is efficacious in the treatment of rheumatic diseases, chronic pain syndromes, hypertension, and metabolic syndrome. The beneficial effects of fasting followed by vegetarian diet in rheumatoid arthritis are confirmed by randomized controlled trials. Further beneficial effects of fasting are supported by observational data and abundant evidence from experimental research which found caloric restriction and intermittent fasting being associated with deceleration or prevention of most chronic degenerative and chronic inflammatory diseases. Intermittent fasting may also be useful as an accompanying treatment during chemotherapy of cancer. A further beneficial effect of fasting relates to improvements in sustainable lifestyle modification and adoption of a healthy diet, possibly mediated by fasting-induced mood enhancement. Various identified mechanisms of fasting point to its potential health-promoting effects, e.g., fasting-induced neuroendocrine activation and hormetic stress response, increased production of neurotrophic factors, reduced mitochondrial oxidative stress, general decrease of signals associated with aging, and promotion of autophagy. Fasting therapy might contribute to the prevention and treatment of chronic diseases and should be further evaluated in controlled clinical trials and observational studies.
Fasting vs dietary restriction in cellular protection and cancer treatment: from model organisms to patients. Oncogene. 2011 Jul 28;30(30):3305-16. By Lee C, Longo VD.
The dietary recommendation for cancer patients receiving chemotherapy, as described by the American Cancer Society, is to increase calorie and protein intake. Yet, in simple organisms, mice, and humans, fasting–no calorie intake–induces a wide range of changes associated with cellular protection, which would be difficult to achieve even with a cocktail of potent drugs. In mammals, the protective effect of fasting is mediated, in part, by an over 50% reduction in glucose and insulin-like growth factor 1 (IGF-I) levels. Because proto-oncogenes function as key negative regulators of the protective changes induced by fasting, cells expressing oncogenes, and therefore the great majority of cancer cells, should not respond to the protective signals generated by fasting, promoting the differential protection (differential stress resistance) of normal and cancer cells. Preliminary reports indicate that fasting for up to 5 days followed by a normal diet, may also protect patients against chemotherapy without causing chronic weight loss. By contrast, the long-term 20 to 40% restriction in calorie intake (dietary restriction, DR), whose effects on cancer progression have been studied extensively for decades, requires weeks-months to be effective, causes much more modest changes in glucose and/or IGF-I levels, and promotes chronic weight loss in both rodents and humans. In this study, we review the basic as well as clinical studies on fasting, cellular protection and chemotherapy resistance, and compare them to those on DR and cancer treatment. Although additional pre-clinical and clinical studies are necessary, fasting has the potential to be translated into effective clinical interventions for the protection of patients and the improvement of therapeutic index.
Alternate-day fasting and chronic disease prevention: a review of human and animal trials. Am J Clin Nutr. 2007 Jul;86(1):7-13. By Varady KA, Hellerstein MK.
Calorie restriction (CR) and alternate-day fasting (ADF) represent 2 different forms of dietary restriction. Although the effects of CR on chronic disease prevention were reviewed previously, the effects of ADF on chronic disease risk have yet to be summarized. Accordingly, we review here animal and human evidence concerning ADF and the risk of certain chronic diseases, such as type 2 diabetes, cardiovascular disease, and cancer. We also compare the magnitude of risk reduction resulting from ADF with that resulting from CR. In terms of diabetes risk, animal studies of ADF find lower diabetes incidence and lower fasting glucose and insulin concentrations, effects that are comparable to those of CR. Human trials to date have reported greater insulin-mediated glucose uptake but no effect on fasting glucose or insulin concentrations. In terms of cardiovascular disease risk, animal ADF data show lower total cholesterol and triacylglycerol concentrations, a lower heart rate, improved cardiac response to myocardial infarction, and lower blood pressure. The limited human evidence suggests higher HDL-cholesterol concentrations and lower triacylglycerol concentrations but no effect on blood pressure. In terms of cancer risk, there is no human evidence to date, yet animal studies found decreases in lymphoma incidence, longer survival after tumor inoculation, and lower rates of proliferation of several cell types. The findings in animals suggest that ADF may effectively modulate several risk factors, thereby preventing chronic disease, and that ADF may modulate disease risk to an extent similar to that of CR. More research is required to establish definitively the consequences of ADF.
Can short-term dietary restriction and fasting have a long-term anticarcinogenic effect? Interdiscip Top Gerontol. 2007;35:176-92. By Klebanov S.
Long-term dietary restriction (DR) robustly inhibits various types of carcinogenesis in rodents. Because malignancies are a major cause of death in humans, reducing the incidence or, at least, delaying the time of onset of neoplasia may significantly increase longevity of a large proportion of the human population. Long-term DR may not however be practical in humans and, judging from religious practices, several days of fasting to several weeks of DR is what a large segment of the human population can adhere to. In contrast to long-term DR, a single episode of fasting or several fasting-refeeding cycles did not have any long-lasting beneficial and usually had even a deleterious effect on carcinogenesis in rodent models. On the other hand, DR of a relatively short (1-3 months) duration often significantly increased latency and reduced the incidence of cancer over the entire life span. These results suggest that the immediate anticarcinogenic action of DR is to slow down the expansion of initiated clones, but that several months of DR may be sufficient for the elimination of a significant portion of initiated precancerous clones through apoptosis. The development of optimized DR regimens for humans will be contingent on further advances in our understanding of the mechanisms of cancer suppression by DR.
[Note: Dr. Chen is offering special training of Qigong Fasting to public in Columbia, Maryland from May 19 to May 22, Please check up the page for more information: http://yang-sheng.com/?p=10715]
Kevin W Chen, Ph.D. – 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).