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Open Access Research

Dietary protein and plasma total homocysteine, cysteine concentrations in coronary angiographic subjects

Yunjun Xiao12, Yuan Zhang3, Min Wang1, Xinrui Li1, Min Xia1 and Wenhua Ling1*

Author Affiliations

1 Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-sen University, Number 74 Zhongshan Road 2, 510080 Guangzhou, Guangdong, China

2 Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, Guangdong, China

3 Department of Cardiology, Guangzhou Military General Hospital, Guangzhou, Guangdong, China

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Nutrition Journal 2013, 12:144  doi:10.1186/1475-2891-12-144

Published: 7 November 2013

Abstract

Background

Dietary patterns are associated with plasma total homocysteine (tHcy) concentrations in healthy populations, but the associations between dietary protein and tHcy, total cysteine (tCys) in high risk populations are unclear. We therefore examined the association between dietary protein and tHcy and tCys concentrations in coronary angiographic subjects.

Methods

We conducted a cross-sectional study of 1015 Chinese patients who underwent coronary angiography (40–85 y old). With the use of food-frequency questionnaires, we divided the total protein intakes into high animal-protein and high plant-protein diets. Circulating concentrations of tHcy and tCys were simultaneously measured by high-performance liquid chromatography with fluorescence detection.

Results

We found that high animal-protein diet was positively associated with hyperhomocysteinemia after adjustment for potential confounders, with the subjects in the highest quartile of intake having the greatest increase in risk (OR: 4.14, 95% CI: 2.67-6.43), whereas high plant-protein diet was inversely related to hyperhomocysteinemia, with a higher intake being protective. Compared with the first quartile of intake, the adjusted OR was 0.59 (95% CI: 0.38-0.91) for the fourth quartile. The total protein intake was positively associated with the risk of hypercysteinemia and the participants in highest quartile had significant OR of 1.69 (95% CI: 1.02-2.87) compared with those in lowest quartile. In multivariate linear regression analyses, high animal-protein and total-protein intakes were positively associated with plasma tHcy and tCys concentrations. The plant-protein intake was a negative determinant of plasma tHcy concentrations.

Conclusions

High animal-protein diet was positively associated with high tHcy concentrations, whereas high plant-protein diet was inversely associated with tHcy concentrations. Furthermore the total protein intake was strongly related to tCys concentrations.

Keywords:
Diet; Dietary protein; Total homocysteine; Total cysteine; Coronary artery disease