The relationship between diet and cognitive function in adult cancer survivors: a systematic review
To perform a systematic review identifying how dietary factors are related to cognitive function in cancer survivors who are not currently undergoing primary treatment.
Using the PRISMA framework, a search was conducted for studies published before February 2019 across multiple databases, identifying 2304 unique articles. Twelve met final inclusion criteria and were evaluated through narrative synthesis. This review was registered with the International Prospective Register Of Systematic Reviews (CRD42018111941).
Included studies were heterogeneous in methodology and in dietary and cognitive variables investigated making direct comparisons difficult. Evidence of a relationship between diet and cognition was mixed; the most consistent evidence was identified in relation to a positive relationship between fruit and vegetable intake and cognitive function (both self-reported and objectively tested) in five out of six studies, but was not concordant across all studies.
Preliminary evidence exists that a greater fruit and vegetable intake is associated with better cognitive functioning in cancer survivors, as has been reported in healthy populations; however, these data are correlational and include relatively small samples. Most evidence related to breast cancer survivors, with individual studies extending to colorectal and stomach cancer survivors. Experimental trials are needed to identify causal attribution of dietary factors on cognitive function in cancer survivors.
Implications for cancer survivors
At this time, there is not sufficient evidence to make dietary or nutritional recommendations specifically for improving cognitive function in cancer survivors. This should be considered in light of the general paucity of research on this subject, necessitating further investigations.
KeywordsCancer Cancer survivors Cognition Cognitive function Diet Nutrition
The authors would like to acknowledge the work of the research assistant Daria Gutteridge for her assistance with study screening. This research was made possible thanks to the Australian Government Research Training Program (RTP) fee offset scholarship funding DC.
DC contributed to the study conception and design, overall study coordination, data collection/screening/ reduction/interpretation, sourcing funds, analysis of data, and drafting and writing the manuscript. AH and AC contributed to study conception and design, data screening/interpretation, overall study coordination, advice on analysis, and drafting the manuscript. AC additionally contributed to data collection. SD contributed to data collection/cleaning/analysis, and drafting the manuscript. SB contributed to study conception and design, overall study coordination, sourcing funds, advice on analysis, and drafting the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This review does not contain any studies with human participants performed by any of the authors.
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