Abstract
Chronic pain remains a significant issue among breast cancer survivors, affecting their quality of life despite advancements in treatment. This thesis explores the link between nutrition and chronic pain in this population, aiming to understand how dietary factors influence pain outcomes. The research employed a comprehensive approach to elucidate this relationship.
The research began with a systematic review of experimental and observational studies investigating the association or interaction between nutrition/ dietary
supplements and chronic pain in cancer patients or survivors, following a clear research agenda. Only two studies met the inclusion criteria: one tested vitamin C and
found no effect on pain, while the other evaluated glucosamine and chondroitin and reported pain improvement after 12 and 24 weeks. Complementing this, a narrative
review investigated mechanisms and pathways including obesity, malnutrition, nutritional deficiencies, diet quality, the immune system, systemic inflammation, and
gut microbiota that might mediate the relationship between nutrition and chronic pain in cancer survivors. It also examined dietary interventions for weight management,
improving diet quality, and regulating inflammation and gut microbiota, highlighting their potential impact on these pain-related mechanisms.
Following this, the thesis examined the specific impact of nutritional factors on chronic pain in female breast cancer survivors. A cross-sectional study explored dietary intake
(including overall energy intake, macronutrient and micronutrient intake), body mass index (BMI), and body composition (including body-fat percentage, body-fat mass, fatfree mass, total body water, visceral fat and basal metabolic rate), and pain, revealing no significant overall link between diet and pain. Additionally, we analysed how these
factors varied among pain subgroups based on pain severity, neuropathic pain and central sensitisation (assessed by pain scores Brief Pain Inventory, Central Sensitisation Inventory and Douleur Neuropathique 4). Although no overall link between diet and pain was found, differences emerged among pain subgroups. Survivors with neuropathic pain had higher protein intake compared to those without, and those with central sensitisation had higher water intake. Additionally, higher BMI, body-fat percentage, body-fat mass, and visceral fat were positively associated with neuropathic pain. Notably, survivors with neuropathic pain had significantly higher levels of these body composition metrics compared to those without neuropathic pain. The case-control study compared diet quality and dietary intake between female breast cancer survivors with chronic pain and healthy pain-free controls. The analysis revealed no significant differences in overall diet quality as measured by Healthy Eating Index-2015 scores between the two groups. However, breast cancer survivors had a lower Dietary Inflammatory Index (DII) score, indicating a less pro-inflammatory diet. They also had higher intakes of omega-3 fatty acids, vitamin B6, vitamin B12, vitamin A, carotene, vitamin D, and magnesium, and lower sodium intake compared to controls. The results suggest that a diet rich in anti-inflammatory and antioxidantrich foods, particularly fruits, are associated with better pain outcomes, while higher intakes of pro-inflammatory foods, such as dairy and total protein, correlates with increased pain. The correlations found in the DII analysis were complex, such as showing both negative associations between cholesterol intake and pain sensitivity and positive associations between anti-inflammatory nutrients (e.g., omega 3, vitamin B and vitamin A) and pain symptoms (pain severity, pain interference, neuropathic pain), underscoring the complicated relationship between dietary factors and chronic pain in breast cancer survivors.
In the final part of the thesis, a randomised controlled cross-over study investigated the impact of glucose metabolism on chronic pain. This study found that female breast
cancer survivors with chronic pain had a significantly higher postprandial glycaemic response to sucrose compared to healthy pain-free controls, indicating impaired glucose tolerance. The difference in response between sucrose and isomaltulose was greater in survivors, suggesting a higher risk of impaired glucose metabolism. Correlation analyses revealed both positive and negative associations between postprandial glycaemic response after sucrose consumption and various pain assessments in these survivors.
In conclusion, this thesis provides valuable insights into the links between nutrition and chronic pain in breast cancer survivors. While overall dietary intake was not strongly
associated with pain, specific factors such as body composition and anti-inflammatory dietary patterns were linked to various pain outcomes. Impaired glucose metabolism
also emerged as a factor related to increased pain sensitivity. These results suggest that (personalised) nutritional interventions could be beneficial in managing chronic
pain in this population. Despite these contributions, the research also highlights several areas needing further investigation to fully understand these complex
relationships and their implications in chronic pain management in breast cancer survivors.
The research began with a systematic review of experimental and observational studies investigating the association or interaction between nutrition/ dietary
supplements and chronic pain in cancer patients or survivors, following a clear research agenda. Only two studies met the inclusion criteria: one tested vitamin C and
found no effect on pain, while the other evaluated glucosamine and chondroitin and reported pain improvement after 12 and 24 weeks. Complementing this, a narrative
review investigated mechanisms and pathways including obesity, malnutrition, nutritional deficiencies, diet quality, the immune system, systemic inflammation, and
gut microbiota that might mediate the relationship between nutrition and chronic pain in cancer survivors. It also examined dietary interventions for weight management,
improving diet quality, and regulating inflammation and gut microbiota, highlighting their potential impact on these pain-related mechanisms.
Following this, the thesis examined the specific impact of nutritional factors on chronic pain in female breast cancer survivors. A cross-sectional study explored dietary intake
(including overall energy intake, macronutrient and micronutrient intake), body mass index (BMI), and body composition (including body-fat percentage, body-fat mass, fatfree mass, total body water, visceral fat and basal metabolic rate), and pain, revealing no significant overall link between diet and pain. Additionally, we analysed how these
factors varied among pain subgroups based on pain severity, neuropathic pain and central sensitisation (assessed by pain scores Brief Pain Inventory, Central Sensitisation Inventory and Douleur Neuropathique 4). Although no overall link between diet and pain was found, differences emerged among pain subgroups. Survivors with neuropathic pain had higher protein intake compared to those without, and those with central sensitisation had higher water intake. Additionally, higher BMI, body-fat percentage, body-fat mass, and visceral fat were positively associated with neuropathic pain. Notably, survivors with neuropathic pain had significantly higher levels of these body composition metrics compared to those without neuropathic pain. The case-control study compared diet quality and dietary intake between female breast cancer survivors with chronic pain and healthy pain-free controls. The analysis revealed no significant differences in overall diet quality as measured by Healthy Eating Index-2015 scores between the two groups. However, breast cancer survivors had a lower Dietary Inflammatory Index (DII) score, indicating a less pro-inflammatory diet. They also had higher intakes of omega-3 fatty acids, vitamin B6, vitamin B12, vitamin A, carotene, vitamin D, and magnesium, and lower sodium intake compared to controls. The results suggest that a diet rich in anti-inflammatory and antioxidantrich foods, particularly fruits, are associated with better pain outcomes, while higher intakes of pro-inflammatory foods, such as dairy and total protein, correlates with increased pain. The correlations found in the DII analysis were complex, such as showing both negative associations between cholesterol intake and pain sensitivity and positive associations between anti-inflammatory nutrients (e.g., omega 3, vitamin B and vitamin A) and pain symptoms (pain severity, pain interference, neuropathic pain), underscoring the complicated relationship between dietary factors and chronic pain in breast cancer survivors.
In the final part of the thesis, a randomised controlled cross-over study investigated the impact of glucose metabolism on chronic pain. This study found that female breast
cancer survivors with chronic pain had a significantly higher postprandial glycaemic response to sucrose compared to healthy pain-free controls, indicating impaired glucose tolerance. The difference in response between sucrose and isomaltulose was greater in survivors, suggesting a higher risk of impaired glucose metabolism. Correlation analyses revealed both positive and negative associations between postprandial glycaemic response after sucrose consumption and various pain assessments in these survivors.
In conclusion, this thesis provides valuable insights into the links between nutrition and chronic pain in breast cancer survivors. While overall dietary intake was not strongly
associated with pain, specific factors such as body composition and anti-inflammatory dietary patterns were linked to various pain outcomes. Impaired glucose metabolism
also emerged as a factor related to increased pain sensitivity. These results suggest that (personalised) nutritional interventions could be beneficial in managing chronic
pain in this population. Despite these contributions, the research also highlights several areas needing further investigation to fully understand these complex
relationships and their implications in chronic pain management in breast cancer survivors.
| Original language | English |
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| Award date | 21 Jan 2025 |
| Publication status | Published - 2025 |