Monounsaturated versus polyunsaturated dietary fat and serum lipids.
Monounsaturated versus polyunsaturated dietary fat and serum lipids.
Year: 1995
Authors: C D Gardner, H C Kraemer.
Publication Name: Arteriosclerosis, Thrombosis & Vascular Biology.
Publication Details: Volume 15; Page 1917.
Abstract:
It is currently unclear whether MUFA or PUFA are preferable for optimal serum lipid levels. Between 1957 and 1993, several equations to predict changes in total-C and LDL-C resulting from dietary fat and cholesterol intakes were developed. Each of these predictive equations consistently suggested that PUFA lowered serum total-C and LDL-C levels, whereas MUFA had a neutral effect. These findings have been challenged and now it is frequently cited that MUFAs are preferred over PUFAs. The purpose of this investigation was to address the controversy regarding a differential effect of monounsaturates versus polyunsaturates on serum lipids. A meta-analytical approach was used to pool results from randomized dietary intervention trials that tested for a differential effect on serum lipids of a high-mono versus a high-poly fat diet, exchanging primarily oils while keeping total fat, saturated fat, fiber, and dietary cholesterol intake constant between the intervention diets. Fourteen studies (1983 through 1994) were identified that met six inclusion criteria. Standardized effect sizes (observed treatment difference in mean end-point lipid levels, divided by the pooled SD) were calculated for individual studies and individual effect sizes were pooled. The results of this meta-analysis indicated that there are no significant differences in total-C, LDL-C, or HDL-C levels in response to the dietary exchange of oils high in MUFA or PUFA. This absence of an effect was observed across a wide range (5% to 25% kcal) of MUFA versus PUFA exchanges in the various studies and for a diverse set of participants (eg, wide age range, wide range of baseline serum lipid levels). Triglyceride levels were modestly but consistently lower on the diets high in PUFA. Replacement of saturated fat with either MUFA or PUFA led to significant decreases in total and LDL cholesterol. Neither MUFA nor PUFA significantly changed HDL cholesterol or triglyceride levels relative to the high-saturated fat diets. The evidence from this meta-analysis strongly indicates that there is no significant difference in LDL or HDL cholesterol levels when oils high in either MUFA or PUFA are exchanged in the diet. The authors recommend that any dietary recommendations for the use of one in preference to the other should be based on outcomes other than serum cholesterol levels.
