We thank Kristen MacEachern and Joseph Mercola for their comments. We apologize for the error in our original article1 suggesting that hypertriglyceridemia be treated with a 10% fat diet (see correction in the Jan. 7, 2003, issue of CMAJ). The recommendation of a 10% fat diet was intended for treatment of chylomicronemia.
Mercola makes the valid point that low-fat diets generally lead to increases in fasting serum triglyceride levels. This issue has been extensively reviewed by Anderson and colleagues,2 who, using a formula developed by Mensink and Katan,3 calculated that depending on the presence or absence of fibre in a low-fat diet, there may be an increase of between 0.5 and 0.8 mmol/L in fasting serum triglycerides.
However, measured changes in fasting serum triglyceride levels, although small (less than 0.1 mmol/L), were in the opposite direction.4,5,6 Postprandial triglycerides decline with low-fat diets but increase with lower-carbohydrate, high-protein diets, which are higher in fat content.7 Postprandial remnant particles, particularly the triglyceride-rich particles, are the most atherogenic. This finding suggests that despite somewhat higher fasting serum triglyceride levels, the lower-fat diets may be preferable. In addition, if the sources of carbohydrates are foods with a low glycemic index (e.g., whole-wheat breads, cereals, grains and legumes) and if the amount of fibre in the diet is increased, these changes in triglyceride levels appear to have little clinical significance.
Another argument in favour of lower-fat diets is the epidemiologic data on the relation between diets higher in animal fats and risk of coronary artery disease. Lower-fat diets have been associated with a reduction in nonfatal cardiovascular events.8 Furthermore, there are indications that higher-fat diets may be associated with insulin resistance.9,10
Michelle A. Fung Clinical Fellow Department of Endocrinology Clinical Investigator Program Jiri J. Frohlich Professor Department of Pathology and Laboratory Medicine University of British Columbia Vancouver, BC
References
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