Low-carbohydrate diets, glycemic index, glycemic load, and the risk of colorectal carcinogenesis
Principal Investigator
About this CDAS Project
Study
PLCO
(Learn more about this study)
Project ID
PLCO-732
Initial CDAS Request Approval
Feb 5, 2021
Title
Low-carbohydrate diets, glycemic index, glycemic load, and the risk of colorectal carcinogenesis
Summary
In recent years, diet methods for weight control and their impact on health and survival have received much attention. Particularly, controversial are the carbohydrate-restricted diets that run counter to conventional dietary advice for weight loss, that is, caloric restriction. From a short-term perspective, low-carbohydrate, high-protein diets, or low-carbohydrate, high-fat diets, have been shown to be at least equivalent to conventional methods for weight loss and cardiovascular disease risk reduction. Many experimental studies indicate that carbohydrate-restricted diets may improve fasting glucose, triglycerides, HDL cholesterol and insulin resistance in patients with type 2 diabetes, though a high protein content is generally not recommended for people with diabetes because of the risk of nephropathy. In contrast to reported positive health effects of carbohydrate restriction, increased free fatty acids and LDL cholesterol were observed in a recent experimental study. From a long-term perspective, the health effects of carbohydrate-restricted diets are not well known.
In cancer, a high consumption of carbohydrate-rich foods, such as fruit, vegetables and whole grain, has been associated with a reduced risk of many types of cancer, whereas high consumption of meat, especially red or processed meat, may increase the risk of colorectal cancer. In a recent American observational study, an increased risk of diabetes was seen in men with a lower intake of carbohydrates and a higher intake of animal protein and fat over a period of 20 years, but a similar study in women showed no increased risk. More conclusive evidence is needed.
Colorectal carcinogenesis is a continuous progress, and colorectal cancer arises from malignant transformation of adenomas. Given that, it is possible that low-carbohydrate diet, glycemic index, and glycemic load play different roles in different stages of cancer progression.
As such, our current objective is to examine the association between low-carbohydrate diet, glycemic index, and glycemic load and colorectal carcinogenesis using data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial prospective cohort. The PLCO is a well characterized and diverse study population with large number of cancer cases that would provide ample power.
In cancer, a high consumption of carbohydrate-rich foods, such as fruit, vegetables and whole grain, has been associated with a reduced risk of many types of cancer, whereas high consumption of meat, especially red or processed meat, may increase the risk of colorectal cancer. In a recent American observational study, an increased risk of diabetes was seen in men with a lower intake of carbohydrates and a higher intake of animal protein and fat over a period of 20 years, but a similar study in women showed no increased risk. More conclusive evidence is needed.
Colorectal carcinogenesis is a continuous progress, and colorectal cancer arises from malignant transformation of adenomas. Given that, it is possible that low-carbohydrate diet, glycemic index, and glycemic load play different roles in different stages of cancer progression.
As such, our current objective is to examine the association between low-carbohydrate diet, glycemic index, and glycemic load and colorectal carcinogenesis using data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial prospective cohort. The PLCO is a well characterized and diverse study population with large number of cancer cases that would provide ample power.
Aims
To examine the association between low-carbohydrate diet, glycemic index, and glycemic load and colorectal carcinogenesis using data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial prospective cohort.
Collaborators
Kang Wang
Department of the Endocrine and Breast Surgery, The First Affiliated hospital of Chongqing Medical university, Chongqing, PRC