心血管疾病的危险因素:膳食中的胆固醇和蛋黄

【英】Spence JD,Jenkins DJ,Davignon J

【编者导读】一般认为:食物摄入的胆固醇和鸡蛋黄对健康人的健康并无危害,甚至有利于健康。但是伦敦罗巴茨研究所的中风预防与动脉粥样硬化研究中心研究表明:膳食胆固醇和鸡蛋黄对动脉是有害的。具有心血管疾病发病风险的患者应限制胆固醇的摄入量。当中风或心肌梗死后才禁食鸡蛋黄就好比得了肺癌才开始戒烟一般:有必要,但已为时过晚。

摘要

在加拿大市民和医疗工作者中普遍流行着一种误解,即越来越多的人们认为:食物摄入的胆固醇和鸡蛋黄对身体无害。通常推荐每天饮食所摄入的胆固醇应限制在200毫克以下(less than 200 mg/day),但是一枚大的鸡蛋黄所含胆固醇含量接近275毫克,已超过了每天胆固醇所推荐的摄入量。虽然有研究表明摄入鸡蛋对健康人并无危害,然而,此类结果可能缺乏对低危人群(low-risk population)临床相关性增加的相应研究。此外,研究表明,研究观察期间,在所有的志愿者中糖尿病的发病风险各异,每天进食一枚鸡蛋的志愿者的发病风险是每周进食少于一枚鸡蛋的志愿者的两倍。进食不仅仅涉及空腹胆固醇,更主要的是餐后胆固醇、饱和脂肪酸、氧化应激和炎症反应的作用。然而将问题的焦点错误地集中于空腹脂肪,就会掩盖了以下三个重要问题:膳食胆固醇会使低密度脂蛋白更容易氧化、膳食胆固醇会提高餐后血脂并增强膳食中饱和脂肪酸的负面作用。包括鸡蛋黄在内的膳食胆固醇对动脉是有害的。具有心血管疾病发病风险的患者应限制胆固醇的摄入量。当中风或心肌梗死后才禁食鸡蛋黄,此行为形同得了肺癌以后才戒烟一般:有必要,但已为时过晚。目前研究表明:在大众和医疗工作者中普遍认为的膳食胆固醇有利于健康的观点是错误的,现在正是需要纠正这个错误概念的时候。

(编者注:富含胆固醇食物主要有动物性食品、蛋类、部分海产品。其中动物性食品中以动物内脏较为丰富,蛋类中鸡蛋黄含量较多。)

文章来源:伦敦罗巴茨研究所中风预防与动脉粥样硬化研究中心

发表于:2010年11月加拿大《心血管》杂志

PMID:21076725

PMCID:PMC2989358

翻译:悠悠步行者

http://www.ncbi.nlm.nih.gov/pubmed/21076725

备注:免费全文链接:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989358/

Can J Cardiol. 2010 Nov;26(9):e336-9.

 

Dietary cholesterol and egg yolks: not for patients at risk of vascular disease.

Spence JD, Jenkins DJ, Davignon J.

Stroke Prevention & Atheroschlerosis Research Centre, Robarts Research Institute, London, Ontario. dspence@robarts.ca

Abstract

A widespread misconception has been developing among the Canadian public and among physicians. It is increasingly believed that consumption of dietary cholesterol and egg yolks is harmless. There are good reasons for long- standing recommendations that dietary cholesterol should be limited to less than 200 mg/day; a single large egg yolk contains approximately 275 mg of cholesterol (more than a day’s worth of cholesterol). Although some studies showed no harm from consumption of eggs in healthy people, this outcome may have been due to lack of power to detect clinically relevant increases in a low-risk population. Moreover, the same studies showed that among participants who became diabetic during observation, consumption of one egg a day doubled their risk compared with less than one egg a week. Diet is not just about fasting cholesterol; it is mainly about the postprandial effects of cholesterol, saturated fats, oxidative stress and inflammation. A misplaced focus on fasting lipids obscures three key issues. Dietary cholesterol increases the susceptibility of low-density lipoprotein to oxidation, increases postprandial lipemia and potentiates the adverse effects of dietary saturated fat. Dietary cholesterol, including egg yolks, is harmful to the arteries. Patients at risk of cardiovascular disease should limit their intake of cholesterol. Stopping the consumption of egg yolks after a stroke or myocardial infarction would be like quitting smoking after a diagnosis of lung cancer: a necessary action, but late. The evidence presented in the current review suggests that the widespread perception among the public and health care professionals that dietary cholesterol is benign is misplaced, and that improved education is needed to correct this misconception.

PMID:21076725

PMCID:PMC2989358

Free PMC Article:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989358/