The Relationship of Digestible Carbohydrate Intake Level and Cardiovascular Disease and Type 2 Diabetes: A Systematic...

To evaluate the association between the dietary digestible carbohydrate intake level and the incidence of cardiovascular disease (CVD) and type 2 diabetes (T2D).

We searched Embase, MEDLINE, and Cochrane Central from January 1, 2000, to July 19, 2024, to find randomized controlled trials and prospective cohort studies evaluating healthy individuals over 2 years of age, isolating for the effect of the digestible carbohydrate intake level from other macronutrients.

Thirty prospective cohort studies with more than 1.7 million participants were included. Most of the studies reported inadequate confounding adjustment and were deemed to have serious risks of bias. No eligible studies evaluated children under 18 years. The association between the digestible carbohydrate intake level and CVD and T2D was nonlinear, which was supported by a low strength of evidence. The risk of CVD was the lowest at a carbohydrate intake level of 50% of total energy intake. The risk of CVD significantly increased when the carbohydrate intake level exceeded 65% of total energy intake. The risk of incident T2D gradually reduced with increasing carbohydrate intake levels up to 45% of total energy intake, then plateaued between 45% and 55% of total energy intake, before rising with higher carbohydrate intake levels. The nonlinear relationships were overall similar based on sex or geographic location but with variable intake range associated with the lowest risk.

A U-shaped relationship was observed between the intake level of digestible carbohydrates and CVD and T2D. The findings have important implications on the incidence and morbidity of chronic conditions and public health.

clinicaltrials.gov: PROSPERO #CRD42024494567 and CRD42024496101.