The Potential of Fasting and Caloric Restriction to Mitigate Radiation Damage—A Systematic Review

Abstract

Detrimental health effects from ionizing radiation to living organisms is one of the key concerns identified and addressed by Radiation Protection institutions, nationally and internationally on Earth and for human spaceflight. Thus, new methods for mitigating the adverse effects of ionizing radiation are urgently needed for terrestrial health and deep space exploration. Caloric restriction and (intermittent-) fasting have been reported to elicit a variety of immediate and long-term physiological effects. The rapidly growing body of evidence of research studies investigating the effects of caloric restriction and dietary fasting points toward a multitude of benefits affecting numerous physiological systems. Therefore, a systematic review was performed to evaluate the evidence of caloric restriction and dietary fasting on the physiological response to ionizing radiation in humans and animals. All experimental studies of humans, animals, and eukaryotic cell lines available in PubMed, Cochrane library, and specialized databases were searched comparing irradiation post-caloric restriction or fasting to a non-nutritionally restricted control group on a broad range of outcomes from molecular to clinical responses. The initial search yielded 2,653 records. The final analysis included 11 studies. Most studies investigated survival rate or cancer occurrence in animals. Included studies did not reveal any benefit from pre exposure caloric restriction, except when performed with post radiation caloric restriction. However, the effects of pre-exposure fasting suggest increased resilience to ionizing radiation.

Intermittent fasting in the prevention and treatment of cancer

“…Data regarding IF and radiation are limited. 192 A preclinical study in a mouse model of pancreatic cancer examined fasting for 24 hours before abdominal radiation. 193 Fasting reduced toxicity, allowing for increasing doses of radiation, but it did not impair tumor cell death from radiation.…”

Developing, Implementing, and Applying Novel Techniques During Systematic Reviews of Primary Space Medicine Data

“…In all quantitative reviews, a full metaanalysis was not possible as the outcomes were highly heterogeneous across studies and there was poor reporting of space medicine studies. However, all quantitative studies were able to perform effect size analysis and only two 10,27 had to rely on significance result reporting. One review 13 used qualitative methods to present a thematic analysis of technical documents from grey literature sources required to answer the technical nature of the research question.…”

“…However, based on the initial review questions tackled, it is apparent that controlled trials, repeated studies and use of standardized outcome measures across studies often do not exist or have been poorly reported, making Cochrane based meta-analyses not possible for some research questions. Therefore, alternate acceptable analyses were performed in a hierarchy of effect size analysis, qualitative analyses 20,26 (individually or combined with quantitative analysis within an integrated approach) 9 and finally, if no other method is possible and there is a justified reason for continuing, reporting of significance testing results from included papers 27 . In extreme cases if no published data exists on a key topic, an empty review could be published to provide comprehensive gap analysis and used to stimulate primary research.…”

Mitigation of Iron Irradiation-Induced Genotoxicity and Genomic Instability by Postexposure Dietary Restriction in Mice

“…Our findings suggested that DR could activate mechanisms consequently resulting in suppression of radiation-induced genotoxicity and GI. Since the early work by Moreschi and McCay et al [59,60], the rapidly growing body of evidence on the effects from dietary intervention has shown that diet intervention has a great impact on health, pointing to a multitude of benefits affecting numerous physiological systems [61]. Diet intervention also elicits a variety of immediate and long-term physiological effects, in particular, beneficial effects on numerous diseases including cancer in experimental models [22].…”