Findings on the role of foods in the risk of gastrointestinal cancers are not consistent. This thesis studied the role of some essential dietary components that are required for normal development and function, as well as that of balanced and healthy patterns of diet intake, on the risk of gastrointestinal cancers. We show that neither synthetic folic acid nor the blood level folate is associated with an increased risk of colorectal cancer (Chapter 2). However, the results of a large study show that supplementing folic acid and iron at higher levels than provided in the original food may increase the risk for colorectal cancer (Chapter 3). The risk of colorectal cancer also seems not to be increased for pregnant women taking synthetic folic acid according to data from smaller study (Chapter 4). As anticipated, healthy and balanced diet intake patterns are associated with lower risks of gastrointestinal cancers, yet the findings are of insufficient quality to develop dietary recommendations for gastrointestinal cancers prevention (Chapters 5, 6, & 7). Moreover, healthy food intake is inadequate among cancer survivors (Chapter 8). The effect of folic acid and iron, as well as that of a healthy and balanced pattern of food and beverage intake, remain unclear regarding gastrointestinal cancer. Future studies will need to assess the role of inherited features on the effect of essential nutrients in diet and on the healthiest patterns of diet intake needed to prevent gastrointestinal cancer.
|Qualification||Doctor of Philosophy|
|Place of Publication||[Groningen]|
|Publication status||Published - 2020|