EAT FOR HEALTH.ORG



MYTH #7

A low-saturated fat diet is the best diet for preventing coronary artery disease

Low-fat diets lower blood cholesterol.  Therefore, a low-saturated fat diet should be the best diet for preventing heart disease.

A very reliable article (see first reference below) summarized a large number of nutritional studies and concluded that people at high risk for coronary disease do indeed obtain a small benefit from reducing their intake of saturated fat, but it is not at all clear that reducing saturated fat helps individuals at low risk for heart disease. [1]  

The lastest study on this topic is a meta-analysis by Chowdhury et al [2] that analyzed 32 observational studies and 27 randomized controlled trials (this is a lot), and found no evidence for a cardioprotective effect from polyunsaturated fat and cardiovascular risk from saturated fat.  To my mind, this is the end of the line for this type of study.  The results are consistent however one looks at it.  As the authors state "current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fats and low consumption of total saturated fats."

It is worth noting that a low-fat diet containing a lot of highly-refined carbohydrate may actually increase one's risk for heart  disease.  How can this be?  It all depends on the carbohydrate.  Whenever one lowers dietary fat, the fat has to be replaced by something else.  If the replacements are sugars and highly-refined carbohydrate cardiovascular risk is slightly increased.[3]

1. References: Hooper L, et al. Reduced or modified dietary fat for preventing cardiovascular disease (Review). Cochrane Library 2009, issue 4

2. Chowdhury et al.  Association of dietary , circulating, and supplement fatty acids with coronary risk. A systematic review and meta-analysis. Ann Intern Med 2014;160:398-406

 3. Jakobsen MU et al Intake of carbohydrates compared with intake of saturated fatty acids and risk of myocardial infarction: importance of the glycemic index. American Journal of Clinical Nutrition 2010;91:1764-8.