The use of guarana (Paullinia cupana) as a dietary supplement for fatigue in cancer patients: a systematic review with a meta-analysis.

OBJECTIVE

The objective of the present study was to carry out a systematic review with a meta-analysis to assess evidence about the use of guarana fruit to manage fatigue in cancer patients.

METHODOLOGY

The data were extracted from the EMBASE, Scopus, MEDLINE, CENTRAL, and CINAHL databases, in any language, using the descriptors "neoplasms" and "Paullinia" or "guarana powder" and "placebos" and "fatigue". Searches were also conducted to identify any grey literature. Clinical studies with patients who presented cancer-related fatigue as a primary outcome and who used guarana as a dietary supplement were included. The risk of bias in randomized clinical trials was analyzed according to the Cochrane recommendations. The quality of the evidence was assessed using the GRADE system. For studies with the same types of tumors and treatments, meta-analysis was also conducted.

RESULTS

A total of 383 studies were found and, of these, seven were included in the review, for a total of 427 cancer patients. The instruments used to analyze fatigue were the Brief Fatigue Inventory (BFI), the Chalder Fatigue Scale, the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-FATIGUE), and the Piper Scale. Some studies presented a low risk of bias for all the categories. Meta-analysis was conducted for three studies about breast cancer, which presented sufficient data. The use of guarana did not reduce cancer-related fatigue compared with placebo groups (mean of - 0.02 [95% CI - 1.54, 1.50]; p = 0.98) and the quality of evidence according to GRADE was very low.

CONCLUSION

Dietary supplements are used to improve cancer-related fatigue. The results of this review showed that the use of guarana was not superior to the placebo groups, pointing to the need for further studies with better methodological quality.