Abstract
Rice bran arabinoxylan compound (RBAC) is derived from defatted rice bran through enzymatic processing with Lentinus edodes mycelium. This thesis examined the translational research of RBAC as a functional food and nutraceutical, focusing on the health benefits in relation to immunity, aging, and potential clinical applications in cancer treatment, with particular emphasis on its impact on patient quality of life (QoL). The study was carried out through two parallel investigations. The first encompasses a systematic scoping review that searches, identifies, synthesises, and critically appraises the available evidence for RBAC. The second is a randomised control trial (RCT) that investigates the effects and mechanisms of RBAC supplementation on the QoL of patients during active cancer treatment (RBAC-QoL study).
The scoping review identified 98 articles published between 1998 and 2022 on RBAC and the biological activities related to human health or disease. These articles were predominantly based on Biobran MGN-3 (86.73%) and products from two other companies (13.27%). Available evidence from these articles shows that RBAC supplementation reduces oxidative stress and improves immune response by upregulating phagocytosis, enhancing natural killer cell activity, inducing dendritic cell maturation, and promoting T and B cell proliferation. RBAC also inhibits mast cell degranulation to avoid hypersensitivity and downregulates processes in neoplasm angiogenesis. In an aging population, RBAC has been shown to play a role in reducing respiratory infections, lowering inflammaging, and enhancing QoL. RBAC supplementation also prevents neoplasms by restoring the host immune response and promotes cancer cell apoptosis directly. The effects of RBAC supplementation in cancer patients include slowing the growth and spread of cancer, enhancing the efficacies of oncological treatments, and protecting from side effects of chemotherapy and radiation treatment, thus improving QoL. The best available evidence from small RCTs suggests that RBAC improves survival odds in cancer patients by 4-fold in the first year and 3-fold in the second year.
Cancer patient recruitment for the RBAC-QoL study started in 2020 but was delayed due to the COVID-19 pandemic. The trial is expected to be completed in 2024. This thesis reports the detailed study protocol, statistical plan, and data analysis from the first 16 participants (RBAC = 7, placebo = 9). The results show that RBAC significantly improved the Global QoL scores of cancer patients during active treatment compared to those taking placebo powder (F[1,8] = 8.6, p = 0.019, eta2[g] = 0.267). Significant elevations of serum white blood cell count and total protein were also detected in the RBAC group compared to placebo (p < 0.05). Changes in total protein levels correlated highly with white blood cell count (Pearson’s r = 0.539, p < 0.001) and moderately with the global QoL scores (r = 0.338, p = 0.01). Thus, the improvement in QoL during RBAC supplementation could be linked to the immuno-nutritional pathway.
Overall, this thesis is a comprehensive evidence synthesis on RBAC for health, aging, and cancer to date by combining both primary and secondary research methods. Based on the scoping review, translational research on RBAC is shown to be heavily concentrated on basic research, preclinical studies, and small-scale clinical trials. Only four RCTs were classified as T2 research (based on the T0 – T4 translational research stages), which involves translating scientific findings to patients in clinical trials. Future research should further pursue translational evidence through more extensive, robust and large-scale RCTs. With RBAC widely available as a dietary supplement off-the-shelf, translational research to inform clinical practice and public health is required. This research contributes to evidence-based practice by completing the ask, acquire, and appraisal steps to synthesise evidence for RBAC as a valuable reference. It is in the hands of clinicians to apply and evaluate the clinical outcomes of RBAC in practice.
The scoping review identified 98 articles published between 1998 and 2022 on RBAC and the biological activities related to human health or disease. These articles were predominantly based on Biobran MGN-3 (86.73%) and products from two other companies (13.27%). Available evidence from these articles shows that RBAC supplementation reduces oxidative stress and improves immune response by upregulating phagocytosis, enhancing natural killer cell activity, inducing dendritic cell maturation, and promoting T and B cell proliferation. RBAC also inhibits mast cell degranulation to avoid hypersensitivity and downregulates processes in neoplasm angiogenesis. In an aging population, RBAC has been shown to play a role in reducing respiratory infections, lowering inflammaging, and enhancing QoL. RBAC supplementation also prevents neoplasms by restoring the host immune response and promotes cancer cell apoptosis directly. The effects of RBAC supplementation in cancer patients include slowing the growth and spread of cancer, enhancing the efficacies of oncological treatments, and protecting from side effects of chemotherapy and radiation treatment, thus improving QoL. The best available evidence from small RCTs suggests that RBAC improves survival odds in cancer patients by 4-fold in the first year and 3-fold in the second year.
Cancer patient recruitment for the RBAC-QoL study started in 2020 but was delayed due to the COVID-19 pandemic. The trial is expected to be completed in 2024. This thesis reports the detailed study protocol, statistical plan, and data analysis from the first 16 participants (RBAC = 7, placebo = 9). The results show that RBAC significantly improved the Global QoL scores of cancer patients during active treatment compared to those taking placebo powder (F[1,8] = 8.6, p = 0.019, eta2[g] = 0.267). Significant elevations of serum white blood cell count and total protein were also detected in the RBAC group compared to placebo (p < 0.05). Changes in total protein levels correlated highly with white blood cell count (Pearson’s r = 0.539, p < 0.001) and moderately with the global QoL scores (r = 0.338, p = 0.01). Thus, the improvement in QoL during RBAC supplementation could be linked to the immuno-nutritional pathway.
Overall, this thesis is a comprehensive evidence synthesis on RBAC for health, aging, and cancer to date by combining both primary and secondary research methods. Based on the scoping review, translational research on RBAC is shown to be heavily concentrated on basic research, preclinical studies, and small-scale clinical trials. Only four RCTs were classified as T2 research (based on the T0 – T4 translational research stages), which involves translating scientific findings to patients in clinical trials. Future research should further pursue translational evidence through more extensive, robust and large-scale RCTs. With RBAC widely available as a dietary supplement off-the-shelf, translational research to inform clinical practice and public health is required. This research contributes to evidence-based practice by completing the ask, acquire, and appraisal steps to synthesise evidence for RBAC as a valuable reference. It is in the hands of clinicians to apply and evaluate the clinical outcomes of RBAC in practice.
Original language | English |
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Qualification | Doctor of Philosophy |
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Place of Publication | Australia |
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Publication status | Published - 2024 |