Intermittent fasting

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Intermittent fasting ( latin inter mittere interrupt 'suspend') interval fasting or short-term fasting is the name for a food form in which the time, in a certain rhythm, between periods of normal food intake and fasting is changed. In various animal models , intermittent fasting leads to a higher life expectancy and a lower rate of age-related diseases in the animals fed in this way - compared to animals with conventional diet . Many of the effects achieved are similar to those of calorie restriction .

description

Intermittent fasting is followed by periods of non-eating followed by periods of normal nutrition. The rhythm between normal food intake and fasting is constant and, in most laboratory tests, a 24-hour alternation. This means that a phase of 24 hours of fasting is followed by a phase of 24 hours of normal nutrition. During the fasting period, solid food was usually completely avoided in the experiments and liquid was only consumed in the form of water. This form of nutrition is called every other day diet (EOD, "every other day diet") or alternate day fasting (ADF) in the Anglo-Saxon specialist literature . Another version of intermittent fasting is that the alternation between fasting and feeding periods occurs within a day. The 16: 8 method is often used. An 8-hour phase of food intake only begins after a 16-hour food waiting period. Taking into account the night's rest and the absence of breakfast or dinner, this process can be integrated into everyday life without major changes, since the diet does not have to be changed. Water and unsweetened tea or coffee are allowed during the fasting block. In the case of daily rhythm interval fasting, variants with even longer food intake pauses (e.g. 18: 6 or 20: 4) are propagated.

Effects and observations in animals

Since the beginning of the 20th century it has been known from experiments with rodents and many other species that a restriction of food intake - compared to ad libitum nutrition - has a positive effect on the life expectancy of the test animals. In addition, the incidence of many age-related diseases has been shown to be reduced.

Obesity

For many years it was assumed that these positive effects are caused solely by a reduction in energy consumption. A reduced energy consumption, so the thesis, means less stress for the body cells. However, modified studies in the 1980s showed that this simplified explanatory model is obviously wrong. In these more recent studies, the test animals received no food for one day and any of it the next day ( ad libitum ). In this way, the animals were able to compensate for the “starvation day” the next day by “full eating”. Compared with the control group, which was fed ad libitum every day , the mice fed according to EOD had only minor deficits in terms of energy intake. Sometimes their energy intake was even higher and their body weight was maintained.

Increased life expectancy

In addition, the animals fed on a diet lived significantly longer and were significantly more resistant than their conspecifics fed ad libitum every day . As with reduced calorie intake, reduced levels of glucose and insulin were also measured in the serum of the EOD mice . The blood pressure was significantly reduced. The neurons in the brains of these animals were also more resistant to excitotoxic stress induced by kainic acid .

Reduced cancer growth

Intermittent fasting also causes significantly reduced tumor growth in the test animals, both for implanted and induced tumors . In addition, the survival time is increased in tumorous rats and in mice during intermittent fasting. In rats, intermittent fasting also has a cardioprotective effect. These animals also showed a higher resistance to strokes . Intermittent fasting also has a positive effect on kidney function in rats. The glomerular filtration rate (GFR) and renal plasma flow (RPF) could be maintained with increasing age. Fasting, on the other hand, had little effect on glomerular permselectivity .

Probability of survival after major surgery

In one study, chronic heart failure was artificially created in rats by occluding the left coronary artery . Two weeks after the operation, some of the animals were switched to intermittent fasting, the rest were fed normally. In the group switched to intermittent fasting, the survival rate after six weeks was 88.5%, while in the other group it was only 23%. The ratio of heart mass to body mass was significantly lower in the dieted animals (2.4 ± 0.17 to 3.9 ± 0.18; P <0.01). Perfusion tests on the isolated heart showed a significantly better preserved cardiac function in the diet rats. In these animals, a number of angiogenic factors , such as asHIF-1-α, BDNF and VEGF , were also upregulated in the heart. Correspondingly, an increased capillary density in the border area of ​​the ischemic heart muscle as well as an increased expression of VEGF in the heart muscle cells (cardiomyocytes) was determined immunohistochemically in these animals . Anti- apoptosis factors such as Akt and Bcl-2 were also greatly increased.

Reduced incidence of diabetes and diabetes-associated complications

In addition, intermittent fasting in rats significantly slows the progression of diabetic nephropathy . In the model organism BB rat , the incidence of type 1 diabetes mellitus was significantly reduced by intermittent fasting .

Reduced symptoms of Alzheimer's

In transgenic mice of the 3xTgAD type that develop Alzheimer's disease , both the animals with caloric restriction and those with intermittent fasting performed better in terms of their cognitive abilities than their normally fed transgenic conspecifics.

Life extension depending on the age and breed of the test animals

The effects of life extension are, however, strongly dependent on the age at which intermittent fasting was started and the genotype of the test animals. In mice of a certain genotype (A / J), the mean life expectancy and maximum lifespan were even reduced if intermittent fasting was only started at the age of ten months. If you started at the age of six months, there was no significant change, while starting a diet six weeks after birth increased both the mean life expectancy and the maximum life span. In the case of the genotype C57BL / 6J, significantly positive effects in terms of mean life expectancy and maximum life span were recorded at six weeks and six months. Intermittent fasting of this strain at 10 months of age increased the maximum lifespan while the median life expectancy remained unchanged. In contrast, in rats of the Wistar genotype , life was prolonged by intermittent fasting even at the age of 18 months. In the nematode Caenorhabditis elegans , intermittent fasting can increase life expectancy by 40 to 56 percent.

Causes of the positive effects of intermittent fasting in laboratory animals

The causes of the life-prolonging effect in laboratory animals are still largely unclear. Several models are discussed.

According to some authors, the resistance of the body cells is improved by the interplay of anabolic and catabolic processes. In addition, cells and biomolecules that may have been damaged are increasingly being “repaired”.

When you eat, your body releases insulin . Several signal chains are then set in motion via receptor tyrosine kinases . This activates tissue-specific effector proteins or processes. One of the signal chains runs through protein kinases , which has been shown to have a negative effect on life expectancy in model organisms. The cause of this effect is obviously the inhibition of FOXO3 . This transcription factor reduces replicative senescence . In addition, the insulin signal cascade increases the rate of proliferation , which accelerates the breakdown of telomeres at the ends of the chromosomes . If the genes necessary for this signal chain are switched off in the model organism Drosophila ( gene knockout ), the lifespan of these insects increases by a factor of two. Conversely, fasting, that more sirtuin-1 expressed is, which in turn stimulates the expression of FOXO3. FOXO3 puts the cell into a kind of dormant state ( quiescence ), which slows down the cell cycle and increases the production of antioxidant enzymes such as manganese superoxide dismutase (MnSOD) and iron superoxide dismutase (FeSOD) as well as catalase in the cells.

These antioxidant enzymes, in turn, help cells better deal with oxidative stress , which is a major factor in cell aging.

The GTPase RHEB obviously plays an essential role in intermittent fasting. The genes that are upregulated by fasting need this enzyme for their induction .

Different effects of fasting on drug and toxin toxicity

Observations in mice have shown that fasting increases the toxic effect of some substances (e.g. the liver toxicity of paracetamol ), while it decreases it in others (e.g. chemotherapy drugs and the steroid digitoxigenin ).

Intermittent fasting in humans

Intermittent fasting leads to physiological and metabolic changes in humans similar to continuous calorie restriction. A major difference, however, is that significantly higher plasma concentrations of ketone bodies can be detected during intermittent fasting . It is believed that the nutritional pattern of intermittent fasting is more similar to that of humans before the beginning of agriculture and livestock farming than the eating rhythms of modern times and that the human body is still adapted to it.

Broader clinical experiences result from countries with a predominantly Muslim population, in which Ramadan is celebrated annually. The metabolic improvements observed in healthy individuals are very small. Other studies describe an increase in the unfavorable LDL cholesterol and a decrease in the good HDL cholesterol, especially in healthy men. For overweight people who practice Ramadan, the improved body composition returns to its original state after a few weeks.

The studies on overweight people without a religious background also show no advantages for intermittent fasting, neither with 16: 8 fasting (time-restricted eating), 5: 2 fasting, nor with alternate-day fasting (every-other-day- Fasting). The weight loss is no greater than with continuous calorie restriction. The lower cardiovascular and metabolic risk described in observational studies may be due to "reverse causality": people at low risk use intermittent fasting more often, but intermittent fasting does not reduce the risk.

In any case, the results obtained in animal experiments cannot easily be transferred to humans. In many cases, the control group of the test animals was fed ad libitum and had limited opportunities to exercise, which definitely leads to an unhealthy lifestyle due to obesity. It is therefore still largely unclear whether intermittent fasting has any positive effect on people with a low or normal body mass index .

The different types of intermittent fasting

There are different variants of intermittent fasting. The most popular variants are 5: 2 fasting and 16: 8 fasting (time-restricted eating). With 5: 2 fasting, you can eat normally five days a week and then consume a maximum of 500 kilocalories (guideline value for women) or 600 kilocalories (guideline value for men) on the remaining two days. The 16: 8 fast, on the other hand, fasts 16 hours a day. You can then eat normally for the remaining 8 hours of the day. Another variant of intermittent fasting is the Eat-Stop-Eat method, in which you fast for 24 hours one to two days a week.

History

The results of the first controlled animal experiments on intermittent fasting were published in 1934. Mice were used as test animals. Intermittent fasting was limited to two days a week. The observed lengthening of life was rated by the authors as not significant. The intermittently fed males lived on average 745 days, the females 819. In the control group it was 712 and 773 days, respectively. As early as 1887, the Russian doctor from Zealand carried out experiments on chickens. However, he made no statements about the effects on the service life. Sergius Morgulis , professor of biochemistry at the University of Nebraska , conducted intermittent fasting experiments on salamanders in 1913 . But here, too, the research interest was not on the effects on life expectancy, but mainly on the effects on the growth of animals. In 1945, Anton J. Carlson and Frederick Hoelzel of the University of Chicago found both an extension of the life span and a reduced tumor rate in rats that were fed intermittently. They determined the optimal fasting interval to be one day in three days. The mean lifespan of the animals increased by 15% for the females and by 20% for the males.

further reading

Web links

Individual evidence

  1. ↑ a b R. M. Anson et al .: The diet restriction paradigm: a brief review of the effects of every-other-day feeding. In: Age. 27, 2005, pp. 17-25. doi: 10.1007 / s11357-005-3286-2
  2. ↑ Stern-Gesundheit: How healthy is intermittent fasting from March 1, 2017 called on March 29, 2017.
  3. ↑ Ralf Gabler: This is how you get your fat off with intermittent fasting from September 29, 2016 called on April 2, 2017.
  4. ↑ ET Poehlman include: Caloric Restriction Mimetics - Physical Activity and Body Composition Changes. ( Memento of October 17, 2009 in the Internet Archive ) In: J Gerontol A Biol Sci Med Sci. 56, 2001, pp. 45-54. PMID 12088211 (Review)
  5. ↑ a b c S. Honjoh et al: Signaling through RHEB-1 mediates intermittent fasting-induced longevity in C. elegans. In: Nature 457, 2009, pp. 726-730. PMID 19079239 .
  6. ↑ a b E. J. Masoro include: Action of food restriction in delaying the aging process. In: PNAS 79, 1982, pp. 4239-4241. PMID 6955798 .
  7. ↑ a b c d e R. M. Anson, Z. Guo, R. de Cabo, T. Iyun, M. Rios, A. Hagepanos, DK Ingram, MA Lane, MP Mattson: Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. In: Proceedings of the National Academy of Sciences . Volume 100, Number 10, May 2003, pp. 6216-6220, doi: 10.1073 / pnas.1035720100 .
  8. ↑ RE Beauchene et al .: Effect of age of initiation of feed restriction on growth, body composition, and longevity of rats. In: J Gerontol. 41, 1986, pp. 13-19. PMID 3941250 .
  9. ↑ R. Wan et al .: Intermittent food deprivation improves cardiovascular and neuroendocrine responses to stress in rats. In: J Nutr. 133, 2003, pp. 1921-1929. PMID 12771340 .
  10. ↑ D. Kritchevsky: Influence of caloric restriction and exercise on tumorigenesis in rats. In: Proc Soc Exp Biol Med. 193, 1990, pp. 35-38. PMID 2104673 .
  11. ^ NS Rocha et al .: Effects of fasting and intermittent fasting on rat hepatocarcinogenesis induced by diethylnitrosamine. In: Teratog Carcinog Mutagen 22, 2002, pp. 129-138. PMID 11835290 .
  12. ↑ H. Sogawa, C. Kubo: Influence of short-term repeated fasting on the longevity of female (NZB x NZW) F1 mice. In: Mechanisms of aging and development. Volume 115, Number 1-2, May 2000, pp. 61-71, ISSN  0047-6374 . PMID 10854629 .
  13. ^ I. Siegel et al .: Effects of short-term dietary restriction on survival of mammary ascites tumor-bearing rats. In: Cancer Invest. 6, 1988, pp. 677-680. PMID 3245934 .
  14. ^ R. Wan, I. Ahmet, M. Brown, A. Cheng, N. Kamimura, M. Talan, MP Mattson: Cardioprotective effect of intermittent fasting is associated with an elevation of adiponectin levels in rats. In: J. Nutr. Biochem. 21, 2010, pp. 413-417. PMID 19423320 PMC 285425 (free full text).
  15. ^ MP Mattson, R. Wan: Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. In: J Nutr Biochem. 16, 2005, pp. 129-137. PMID 15741046
  16. ↑ JJ Gehrig Jr et al .: Effect of long-term, alternate day feeding on renal function in aging conscious rats. In: Kidney Int . 34, 1988, pp. 620-630. PMID 3199676
  17. ↑ RG Katare et al .: Chronic intermittent fasting improves the survival following large myocardial ischemia by activation of BDNF / VEGF / PI3K signaling pathway. In: Journal of Molecular and Cellular Cardiology 46, 2009, pp. 405-412. PMID 19059263 .
  18. ↑ a b K. Tikoo ua: Intermittent fasting prevents the progression of type I diabetic nephropathy in rats and changes the expression of Sir2 and p53. In: FEBS Lett 581, 2007, pp. 1071-1078. PMID 17316625
  19. ↑ CR Pedersen, I. Hagemann et al: Intermittent feeding and fasting reduces diabetes incidence in BB rats. In: Autoimmunity. Volume 30, Number 4, 1999, pp. 243-250, ISSN  0891-6934 . PMID 10524500 .
  20. ↑ VK Halagappa: Intermittent fasting and caloric restriction ameliorate age-related behavioral deficits in the triple-transgenic mouse model of Alzheimer's disease. In: Neurobiol Dis. 26, 2007, pp. 212-220. PMID 17306982 .
  21. ↑ CL Goodrick et al .: Effects of intermittent feeding upon body weight and lifespan in inbred mice: interaction of genotype and age. In: Mech Aging Dev. 55, 1990, pp. 69-87. PMID 2402168 .
  22. ↑ CL Goodrick et al .: Differential effects of intermittent feeding and voluntary exercise on body weight and lifespan in adult rats. In: J Gerontol. 38, 1983, pp. 36-45. PMID 6848584
  23. ↑ MS Gami, CA Wolkow: Studies of Caenorhabditis elegans DAF-2 / insulin signaling reveal targets for pharmacological manipulation of lifespan. In: Aging cell. Volume 5, Number 1, February 2006, pp. 31-37, doi: 10.1111 / j.1474-9726.2006.00188.x
  24. ↑ T. Aigaki et al.: Longevity determination genes in Drosophila melanogaster. In: Mech Aging Dev. 123, 2002, pp. 1531-1541. PMID 12470891 (Review)
  25. ↑ J. Trapp, M. Jung: The role of NAD + dependent histone deacetylases (sirtuins) in aging. In: Curr Drug Targets 7, 2006, pp. 1553-1560. PMID 17100594 (Review)
  26. ^ B. Martin, MP Mattson, S. Maudsley: Caloric restriction and intermittent fasting: two potential diets for successful brain aging. In: Aging research reviews. Volume 5, Number 3, August 2006, pp. 332-353, doi: 10.1016 / j.arr.2006.04.002
  27. ↑ Fasting of mice: a review , journals.sagepub.com, September 11, 2013.
  28. ↑ NDR: Can fasting support chemotherapy? Retrieved September 30, 2019 .
  29. ↑ Judith Görs: Fasting in the fight against cancer. Retrieved September 30, 2019 .
  30. ↑ For breast and ovarian cancer: Short-term fasting probably makes chemotherapy more effective and easier to tolerate. Retrieved September 30, 2019 .
  31. ↑ MP Mattson et al: Meal size and frequency affect neuronal plasticity and vulnerability to disease: cellular and molecular mechanisms. In: J Neurochem. 84, 2003, pp. 417-431. PMID 12558961
  32. ^ MP Mattson: Energy intake, meal frequency, and health: a neurobiological perspective. In: Annu Rev Nutr. 25, 2005, pp. 237-260. PMID 16011467 (Review)
  33. ↑ M. Maalouf, JM Rho, MP Mattson: The neuroprotective properties of calorie restriction, the ketogenic diet, and ketone bodies. In: Brain research reviews. Volume 59, number 2, March 2009, pp. 293-315, doi: 10.1016 / j.brainresrev.2008.09.002
  34. ^ P. Zimmet, CR Thomas: Genotype, obesity and cardiovascular disease — has technical and social advancement outstripped evolution? In: J Intern Med. 254, 2003, pp. 114-125. PMID 12859692 (Review)
  35. ↑ F. Rollo, M. Ubaldi, L. Ermini, I. Marota: Ötzi's last meals: DNA analysis of the intestinal content of the Neolithic glacier mummy from the Alps. In: Proceedings of the National Academy of Sciences . Volume 99, Number 20, October 2002, pp. 12594-12599, doi: 10.1073 / pnas.192184599
  36. ↑ a b M. P. Mattson: The need for controlled studies of the effects of meal frequency on health. In: The Lancet 365, 2005, pp. 1978-1980. doi: 10.1016 / S0140-6736 (05) 66667-6
  37. ↑ Mo'ez Al-Islam E. Faris, Haitham A. Jahrami, Joud Alsibai, Asma A. Obaideen: Impact of Ramadan Diurnal intermittent fasting on Metabolic Syndrome Components in healthy, non-Muslim Athletic People Aged Over 15 Years: A Systematic Review and meta-analysis . In: The British Journal of Nutrition . October 4, 2019, ISSN  1475-2662 , p. 1-51 , doi : 10.1017 / S000711451900254X , PMID 31581955 .
  38. ↑ Parvin Mirmiran, Zahra Bahadoran, Zahra Gaeini, Nazanin Moslehi, Fereidoun Azizi: Effects of Ramadan intermittent fasting on lipid and lipoprotein parameters: An updated meta-analysis . In: Nutrition, metabolism, and cardiovascular diseases: NMCD . tape 29 , no. 9 , September 2019, ISSN  1590-3729 , p. 906-915 , doi : 10.1016 / j.numecd.2019.05.056 , PMID 31377182 .
  39. ↑ Hamish A. Fernando, Jessica Zibellini, Rebecca A. Harris, Radhika V. Seimon, Amanda Sainsbury: Effect of Ramadan Fasting on Weight and Body Composition in Healthy Non-Athlete Adults: A Systematic Review and Meta-Analysis . In: Nutrients . tape 11 , no. 2 , February 24, 2019, ISSN  2072-6643 , doi : 10.3390 / nu11020478 , PMID 30813495 , PMC 6412279 (free full text).
  40. ↑ Leanne Harris, Sharon Hamilton, Liane B. Azevedo, Joan Olajide, Caroline De Brún: Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis . In: JBI database of systematic reviews and implementation reports . tape 16 , no. 2 , February 2018, ISSN  2202-4433 , p. 507-547 , doi : 10.11124 / JBISRIR-2016-003248 , PMID 29419624 .
  41. ↑ Radhika V. Seimon, Jessica A. Roekenes, Jessica Zibellini, Benjamin Zhu, Alice A. Gibson: Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials . In: Molecular and Cellular Endocrinology . 418 Pt 2, December 15, 2015, ISSN  1872-8057 , p. 153-172 , doi : 10.1016 / j.mce.2015.09.014 , PMID 26384657 .
  42. ↑ Benjamin D. Horne, Joseph B. Muhlestein, Jeffrey L. Anderson: Health effects of intermittent fasting: hormesis or harm? A systematic review . In: The American Journal of Clinical Nutrition . tape 102 , no. 2 , August 2015, ISSN  1938-3207 , p. 464-470 , doi : 10.3945 / ajcn.115.109553 , PMID 26135345 .
  43. ↑ Intermittent fasting: This is what you need to pay attention to with the diet trend . In: FOCUS Online . ( focus.de [accessed on January 3, 2018]).
  44. ^ TB Robertson et al.: The influence of intermittent starvation and intermittent starvation plus nucleic acid on the growth and longevity of the white mouse. In: Aust J Exp Biol Med Sci. 12, 1934, p. 33.
  45. ↑ Fasting. In: Meyers Konversationslexikon. Fourth edition. 1885-1892.
  46. ↑ von Seeland: On the aftermath of food deprivation on nutrition. In: Biol Centralbl. 7, 1887, pp. 145, 184, 214, 246 and 271.
  47. ^ A b A. J. Carlson, F. Hoelzel: Apparent Prolongation of the Life Span of Rats by Intermittent Fasting. In: Journal of Nutrition. 31, 1946, pp. 363-375.
  48. ↑ S. Morgulius: The influence of protracted and intermittent fasting upon growth. In: Am Naturalist. 47, 1913, p. 477.
  49. ↑ A. Howell et al: Energy Restriction for Breast Cancer Prevention. In: HJ Senn et al. (Ed.): Cancer Prevention II. Verlag Springer, 2009, ISBN 978-3-540-69296-6 , p. 100.