Abstract
Dietary fat plays an important role in the primary prevention of cardiovascular disease,
but long-term (≥12 months) effects of different percentages of fat in the diet on
blood lipid levels remain to be established. Our systematic review and meta-analysis
focused on randomized controlled trials assessing the long-term effects of low-fat
diets compared with diets with high amounts of fat on blood lipid levels. Relevant
randomized controlled trials were identified searching MEDLINE, EMBASE, and the Cochrane
Trial Register until March 2013. Thirty-two studies were included in the meta-analysis.
Decreases in total cholesterol (weighted mean difference –4.55 mg/dL [–0.12 mmol/L],
95% CI –8.03 to –1.07; P=0.01) and low-density lipoprotein (LDL) cholesterol (weighted mean difference –3.11
mg/dL [–0.08 mmol/L], 95% CI –4.51 to –1.71; P<0.0001) were significantly more pronounced following low-fat diets, whereas rise
in high-density lipoprotein (HDL) cholesterol (weighted mean difference 2.35 mg/dL
[0.06 mmol/L], 95% CI 1.29 to 3.42; P<0.0001) and reduction in triglyceride levels (weighted mean difference –8.38 mg/dL
[–0.095 mmol/L], 95% CI –13.50 to –3.25; P=0.001) were more distinct in the high-fat diet groups. Including only hypocaloric
diets, the effects of low-fat vs high-fat diets on total cholesterol and LDL cholesterol
levels were abolished. Meta-regression revealed that lower total cholesterol level
was associated with lower intakes of saturated fat and higher intakes of polyunsaturated
fat, and increases in HDL cholesterol levels were related to higher amounts of total
fat largely derived from monounsaturated fat (of either plant or animal origin) in
high-fat diets (composition of which was ∼17% of total energy content in the form
of monounsaturated fatty acids, ∼8% of total energy content in the form of polyunsaturated
fatty acids), whereas increases in triglyceride levels were associated with higher
intakes of carbohydrates. In addition, lower LDL cholesterol level was marginally
associated with lower saturated fat intake. The results of our meta-analysis do not
allow for an unequivocal recommendation of either low-fat or high-fat diets in the
primary prevention of cardiovascular disease.
Keywords
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Biography
L. Schwingshackl is a doctoral degree student, Department of Nutritional Sciences, University of Vienna, Vienna, Austria.
Biography
G. Hoffmann is a professor of nutritional sciences, Faculty of Life Sciences, Department of Nutritional Sciences, University of Vienna, Vienna, Austria.
Article info
Publication history
Published online: October 17, 2013
Accepted:
June 27,
2013
Footnotes
STATEMENT OF POTENTIAL CONFLICT OF INTEREST No potential conflict of interest was reported by the authors.
FUNDING/SUPPORT There is no funding to disclose.
Identification
Copyright
© 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.
