Dietary carbohydrate intake is associated with cardiovascular disease risk in Korean: Analysis of the third Korea National Health and Nutrition Examination Survey (KNHANES III)

Abstract

Background

It is widely recognized that dietary factors play important roles in the development of cardiovascular disease (CVD). We evaluated the association between carbohydrate intake and CVD risk factors, using data from the third Korea National Health and Nutrition Examination Survey (KNHANES III).

Methods

A nationally representative sample of Korean adults (1536 men, 2235 women), aged 20 to 69 years, was divided into three groups according to carbohydrate intake (% of energy), based on the Dietary Reference Intakes (DRI, 55–70% of energy) for Koreans. Then, we examined whether excessive carbohydrate intake was related to CVD risk factors.

Results

Mean carbohydrate intake (% of energy) was 72.8% (321 g/day), above the DRI for Korean adults (55–70%). A high carbohydrate intake (> 70% of energy) was associated with higher BMI, blood pressure, fasting glucose, triglycerides, and LDL-cholesterol levels in women. After adjusting for covariates, such as age, energy intake, alcohol consumption, smoking status, and physical activity, high carbohydrate intakes (> 70% of energy) were significantly associated with diabetes mellitus and low HDL-cholesterol (HDL-C) in women. In men, however, only total cholesterol was inversely associated with high carbohydrate intake.

Conclusion

Higher carbohydrate intakes than the DRI for Koreans were significantly associated with diabetes mellitus and low HDL-C levels in women. These results suggest that improvement of dietary patterns may be an important approach to the prevention of CVD in Korean women.

Introduction

Cardiovascular disease (CVD) has become a leading cause of morbidity and mortality in Korea, as it is in most developed countries [1], [2]. CVD results from complex interactions of multiple genetic and environmental factors, including diabetes mellitus, cigarette smoking, total cholesterol, blood pressure, and physical activity [3], [4], [5]. Dietary patterns are also a major factor contributing to the development of CVD. Many countries have a characteristic dietary pattern, and Koreans usually eat relatively large amounts of carbohydrate, as compared with other countries [6]. However, limited information on CVD risk has been known to be associated with dietary patterns in the Korean population.

In association with CVD risk factors, dietary lipids are the most investigated and the most fully defined [7], [8]. Dietary recommendations emphasize the benefits of low-fat diets in reducing chronic diseases [9]. However, increasing carbohydrate intake may adversely affect lipoprotein concentrations and glucose metabolism [10], [11]. Recently, much research has examined carbohydrates in relation to diabetes or CVD. The quantity and quality of carbohydrates are relevant to cardiovascular risks; both should be considered. It is known that dietary carbohydrates (starch and sugars) elevate insulin levels and have the ability to induce a proatherogenic environment, through activation of various metabolic systems and factors, such as the renin–angiotensin system (RAS) [12], insulin-like growth factor-I (IGF-I) [13], and C-reactive protein (CRP) [14] in humans [13], [15], [16]. In human studies, when total fat is replaced by carbohydrate intake, the result is an elevated plasma concentration of fasting triglycerides and decreased high-density lipoprotein cholesterol (HDL-C), which may counteract the benefit of lowering low-density lipoprotein cholesterol (LDL-C) and lead to a higher risk of developing CVD [17], [18].

The Korean population has one of the highest carbohydrate intakes in the world. The purpose of this study was to examine associations between dietary carbohydrate intake and CVD risk factors in the Korean population.