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Over the past few decades, survival rates among various types of cancer patients have improved dramatically. Dietary changes in response to cancer diagnosis are important and culturally specific. Many Chinese cancer patients consult Traditional Chinese Medicine (TCM) doctors. In TCM, particular food items are seen as harmful to the body of healthy and diseased people. Cancer survivors practicing food avoidance behaviours are at risk of nutritional imbalance and deficiency.
For the first time, this study investigated food avoidance attitudes and behaviours among i) Chinese cancer survivors, ii) TCM doctors and iii) the general public. Participant recruitment was as follows: i) Nasopharyngeal cancer (NPC) and colorectal cancer (CRC) out-patients, between 18 and 69 years of age, seeking follow-up consultations in the Prince of Wales Hospital and the Pamela Youde Nethersole Eastern Hospital in Hong Kong were eligible. ii) An invitation letter and questionnaire were mailed to 1500 TCM doctors systematically sampled from the local TCM registry (n=5868). iii) Telephone numbers were randomly selected from local telephone directories, with 243 eligible respondents identified.
In all three populations, high proportions of participants believed that avoidance of particular food items, avoidance of good nutritional status and reduced amount of food intake would benefit cancer patients’ health including suppression of cancer cell growth, reduction in chance of recurrence and improved treatment effects. Such beliefs are however, not evidence-based. Relatively few participants believed that food avoidance would cause malnutrition. Among cancer patients, food avoidance behaviours were significantly correlated with food avoidance attitudes and lowered intake of proteins. Food avoidance behaviours are therefore a potential health threat to Chinese cancer patients.
Future case-control and cohort study targeting Chinese cancer patients, followed by health promotion, are greatly warranted.
It is hypothesised that cultural specific food avoidance attitudes are prevalent among Traditional Chinese Medicine (TCM doctors), Chinese cancer survivors and the general public in Hong Kong. It is also hypothesised that among Chinese cancer survivors, such attitudes are associated with actual avoidance of particular food items in an uncompensated manner, and that such food avoidance behaviours would have an impact on nutrient intake, quality of life (QOL) and other nutrition-related indicators.
Malnutrition is prevalent among cancer patients and nutritional status affects health outcomes of cancer survivors. It is commonly observed that many cancer patients change their dietary habits, but usually in a health-promoting manner. Such changes are affected by cultural beliefs and practices. TCM doctors are often consulted by cancer patients and since TCM views many commonly consumed food items as being harmful to particular disease groups, this would affect dietary beliefs and practices among Chinese cancer patients. In Western medicine such beliefs are not evidence-based. Despite day-to-day observations, no studies have been published on relevant food avoidance beliefs and behaviours among Chinese cancer patients, TCM doctors and Chinese general populations. This study addresses an important information gap in nutritional studies in cancer research.
This is a cross-sectional pilot study. Measurement tools were developed to assess food avoidance attitudes and behaviours. Reliability and test-retest statistics were generated. The first survey interviewed 150 cancer survivors (NPC and CRC patients) face-to-face during their follow-up visits to 2 hospitals in Hong Kong. The second survey obtained information from 173 local TCM doctors via a mail survey. The third random telephone survey interviewed 156 adults in the Hong Kong general population.
The reliability measures of the constructed scales were in general acceptable. The prevalence of food avoidance belief was high in all three populations. Up to 41-60% of the cancer patients, 43-77% of the TCM doctors and 33-46% of the general public believed that avoidance of specific commonly consumed food items including poultry, seafood other than fish, fish without scales and beef would have a positive effect on their cancer condition, including suppression of cancer growth, enhanced treatment effects, enhanced immunity, reduced chance of cancer recurrence, and alleviation of discomfort. It is therefore not surprising that 86% of the cancer survivors avoided eating at least one such food items (80% avoided eating at least 2 such food items) and that 52% of the general public would recommend their relatives or friends with cancer to avoid eating such food items, whilst 91% of the TCM doctor participants had recommended their cancer patients to avoid eating particular food items in the last 2 years.
The majority of the three populations did not consider that food avoidance among cancer patients would cause malnutrition. Consistently, over half of the cancer survivors with food avoidance attitudes had been advised by their family members, relatives, peer patients and TCM doctors to practice food avoidance. Moreover, a high percentage of the cancer survivors who avoided some protein-rich food items did not compensate by eating other types of protein-rich foods. Amongst cancer survivors, food avoidance behaviours were also significantly associated with lower intake of protein. Associations between food avoidance behaviours and other nutrition or QOL indicators were however, not evident.
As this was a pilot study with a small sample size, further large-scale studies involving multiple Chinese cancer patient populations in China and overseas are warranted.