Higher Intake of Dietary Fiber and Antioxidants Linked to Reduced Risk of All-Cause Mortality in Tumor Survivors

by | Sep 19, 2023 | 2023, Antioxidants, Cancer, Fiber

Written by Taylor Woosley, Staff Writer. After adjusting for confounding factors, total dietary fiber intake was shown to reduce the risk of all-cause mortality (p = 0.011) and tumor mortality (p = 0.003) in cancer survivors. 

Cancer is characterized by uncontrolled proliferation of abnormal cells and aberrant recognition of the immune system1. Increasing evidence has shown that the tumor microenvironment (TME) plays an equally significant role in tumor initiation, progression, and metastasis, as the genetic and epigenetic changes in cancer cells2. The TME is comprised of multiple cell types involved in complex crosstalk, and the composition of these cellular communities influences inflammation, blood vessel formation, and immune responses3.

The Western diet, characterized by a high intake of fat and processed red meat, has emerged as an important contributor to increased cancer risk4. Diet and nutrition are important modifiable factors that may alter the risk of developing cancer, because several dietary components such as excess alcohol consumption, fruit and vegetable intake, and dietary fiber have been shown to significantly impact cancer risk5. Dietary supplementation with antioxidants provides health benefits such as suppressing the development of cancer by reducing reactive oxygen species6.

Tan et al. conducted a cross-sectional analysis to assess the relationship between dietary fiber intake and the Complex Dietary Antioxidant Index (CDAI) on the prognosis of tumor survivors using data from the National Health and Nutrition Examination Surveys (NHANES) from 2001 to 2018. Subject inclusion consisted of being 40 years or older, with complete age information for the first diagnosis of tumor, and with available information on diet, smoking, alcohol use, and chronic diseases. Dietary data was collected during two interviews to assess food consumption 24 hours prior to the interview. CDAI intake was estimated by summing up the standard intake of vitamins A, C, and E, selenium, carotenoid, and zinc.

Confounding factors on death outcomes, including age, sex, race, education, body mass index (BMI), smoking and alcohol consumption, and chronic diseases, was included in the final analysis. A weighted multiple linear regression model was utilized to evaluate the relationship between dietary fiber intake and CDAI scores. Dietary fiber intake was divided into <25 g/day, 25-29g day, and >29 g/day and CDAI was classified using the quartile method. The association between different dietary fiber intake levels and CDAI levels and risk of death was analyzed by adjusting confounding factors.

2077 cancer survivors were included in the final analysis and during the follow-up period (median time: 82 months), there were 676 deaths. Significant findings of the study are as follows:

  • CDAI levels were much lower in deceased individuals than in survivors (-0.12 and 0.60, respectively; p < 0.001).
  • Compared to subjects with dietary fiber intake <25 g/day, CDAI increased 1.2 (95% CI: 0.37-2.02, p = 0.004) and 1.99 (95% CI: 0.75-3.24, p = 0.003) in participants with dietary fiber intake 25-29 g/day and >29 g/day, respectively (both p for trend < 0.001).
  • After adjusting for confounding factors, fiber intakes of 25 to 29 g per day reduced all-cause mortality in patients with tumors (HR: 0.52, 95% CI: 0.33 to 0.83, p = 0.01).
  • Only cancer survivors in the Q4 CDAI (2.029, 78.016) had a reduced risk of cancer mortality (HR: 0.34, 95% CI: 0.16-0.74, p = 0.001).

Results of the study show that increased dietary fiber intake and CDAI levels can decrease the risk of tumor-related mortality and all-cause mortality in tumor survivors. Further research should continue to explore the benefits of fiber and antioxidant consumption for subjects with cancer. Study limitations include the limited nutrition information on subjects beyond the dietary data collected at baseline and the lack of classification of different tumor types.

Source: Tan, Zongbiao, Yang Meng, Lu Li, Yanrui Wu, Chuan Liu, Weiguo Dong, and Changzheng Chen. “Association of Dietary Fiber, Composite Dietary Antioxidant Index and Risk of Death in Tumor Survivors: National Health and Nutrition Examination Survey 2001–2018.” Nutrients 15, no. 13 (2023): 2968.

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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Posted September 19, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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