Cardiovascular disease risk of dietary stearic acid compared with trans, other saturated, and unsaturated fatty acids: a systematic review.

BACKGROUND

High stearic acid (STA) soybean oil is a trans-free, oxidatively stable, non-LDL-cholesterol-raising oil that can be used to replace trans fatty acids (TFAs) in solid fat applications.

OBJECTIVE

The objective was to assess the cardiovascular health effects of dietary STA compared with those of trans, other saturated, and unsaturated fatty acids.

DESIGN

We reviewed epidemiologic and clinical studies that evaluated the relation between STA and cardiovascular disease (CVD) risk factors, including plasma lipids and lipoproteins, hemostatic variables, and inflammatory markers.

RESULTS

In comparison with other saturated fatty acids, STA lowered LDL cholesterol, was neutral with respect to HDL cholesterol, and directionally lowered the ratio of total to HDL cholesterol. STA tended to raise LDL cholesterol, lower HDL cholesterol, and increase the ratio of total to HDL cholesterol in comparison with unsaturated fatty acids. In 2 of 4 studies, high-STA diets increased lipoprotein(a) in comparison with diets high in saturated fatty acids. Three studies showed increased plasma fibrinogen when dietary STA exceeded 9% of energy (the current 90th percentile of intake is 3.5%). Replacing industrial TFAs with STA might increase STA intake from 3.0% (current) to approximately 4% of energy and from 4% to 5% of energy at the 90th percentile. One-to-one substitution of STA for TFAs showed a decrease or no effect on LDL cholesterol, an increase or no effect on HDL cholesterol, and a decrease in the ratio of total to HDL cholesterol.

CONCLUSIONS

TFA intake should be reduced as much as possible because of its adverse effects on lipids and lipoproteins. The replacement of TFA with STA compared with other saturated fatty acids in foods that require solid fats beneficially affects LDL cholesterol, the primary target for CVD risk reduction; unsaturated fats are preferred for liquid fat applications. Research is needed to evaluate the effects of STA on emerging CVD risk markers such as fibrinogen and to understand the responses in different populations.