The Effect of a Plant-Based Diet on Plasma Lipids in Hypercholesterolemic Adults

A Randomized Trial

3 May 2005 | Volume 142 Issue 9 | Pages 725-733

Background: A variety of food combinations can be used to meet national U.S. guidelines for obtaining 30% of energy or less from total fat and 10% of energy or less from saturated fat.

Objective: To contrast plasma lipid responses to 2 low-fat diet patterns.

Design: Randomized clinical trial.

Setting: 4-week outpatient feeding study with weight held constant.

Participants: 120 adults 30 to 65 years of age with prestudy low-density lipoprotein (LDL) cholesterol concentrations of 3.3 to 4.8 mmol/L (130 to 190 mg/dL), body mass index less than 31 kg/m², estimated dietary saturated fat at least 10% of calories, and otherwise general good health.

Measurements: Plasma lipid levels.

Intervention: Two diets, the Low-Fat diet and the Low-Fat Plus diet, designed to be identical in total fat, saturated fat, protein, carbohydrate, and cholesterol content, consistent with former American Heart Association Step I guidelines. The Low-Fat diet was relatively typical of a low-fat U.S. diet. The Low-Fat Plus diet incorporated considerably more vegetables, legumes, and whole grains, consistent with the 2000 American Heart Association revised guidelines.

Results: Four-week changes in the Low-Fat and Low-Fat Plus groups were –0.24 mmol/L (–9.2 mg/dL) versus –0.46 mmol/L (–17.6 mg/dL) for total cholesterol (P = 0.01) and –0.18 mmol/L (–7.0 mg/dL) versus –0.36 mmol/L (–13.8 mg/dL) for LDL cholesterol (P = 0.02); between-group differences were –0.22 mmol/L (–9 mg/dL) (95% CI, –0.05 to –0.39 mmol/L [–2 to –15 mg/dL]) and –0.18 mmol/L (–7 mg/dL) (CI, –0.04 to –0.32 mmol/L [–2 to –12 mg/dL]) for total and LDL cholesterol, respectively. The 2 diet groups did not differ significantly in high-density lipoprotein cholesterol and triglyceride levels.

Limitations: 4-week duration.

Conclusions: Previous national dietary guidelines primarily emphasized avoiding saturated fat and cholesterol; as a result, the guidelines probably underestimated the potential LDL cholesterol-lowering effect of diet. In this study, emphasis on including nutrient-dense plant-based foods, consistent with recently revised national guidelines, increased the total and LDL cholesterol-lowering effect of a low-fat diet.

Editors' Notes Context People can achieve recommended fat intake while consuming high or low amounts of vegetables, fruits, legumes, and whole grains. Contribution This 4-week randomized trial compared 2 diets with different vegetable, fruit, legume, and whole-grain content but identical total fat, saturated fat, protein, carbohydrate, and cholesterol content. The 59 adults who consumed high amounts of vegetables, fruits, legumes, and whole grains had greater improvements in total and low-density lipoprotein cholesterol levels than the 61 adults who ate low amounts of these foods. Implications At least over the short term, greater improvements in low-density lipoprotein and total cholesterol are an additional benefit of diets high in vegetables, fruits, legumes, and whole grains. –The Editors

 

Author and Article Information

From Stanford University Medical School and Stanford University Medical Center, Stanford, and Health Science Research Studies Center, Los Altos, California.

Acknowledgments: The authors gratefully acknowledge the work of Karla J. Oliveira, MS, RD, for menu design and prestudy diet assessment; Pat Kolar for her work as study coordinator; and David Ahn, RD, PhD, for data programming and statistical analyses.

Grant Support: By NIH grant R01 HL57386 and by Human Health Service grant M01-RR00070, General Clinical Research Centers, National Center for Research Resources, National Institutes of Health.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Christopher D. Gardner, PhD, Hoover Pavilion, N229, 211 Quarry Road, Stanford, CA 94305-5705; e-mail, mailto:cgardner{at}stanford.edu.

Current Author Addresses: Drs. Gardner, Rigby, and Farquhar and Ms. Chatterjee: Hoover Pavilion, N229, 211 Quarry Road, Stanford, CA 94305-5705.

Ms. Coulston: 1386 Cuernavaca Circulo, Mountain View, CA 94040-3571.

Dr. Spiller: Health Research and Studies Center, 340 Second Street, Suite 7, Box 338, Los Altos, CA 94023-0338.

Author Contributions: Conception and design: C.D. Gardner, A. Coulston, G. Spiller, J.W. Farquhar.

Analysis and interpretation of the data: C.D. Gardner, A. Coulston, A. Rigby, G. Spiller, J.W. Farquhar.

Drafting of the article: C.D. Gardner, A. Coulston, A. Rigby, G. Spiller, J.W. Farquhar.

Critical revision of the article for important intellectual content: C.D. Gardner, A. Coulston, A. Rigby, G. Spiller, J.W. Farquhar.

Final approval of the article: C.D. Gardner, A. Coulston, A. Rigby, G. Spiller, J.W. Farquhar.

Provision of study materials or patients: C.D. Gardner, L. Chatterjee.

Statistical expertise: C.D. Gardner.

Obtaining of funding: C.D. Gardner, J.W. Farquhar.

Administrative, technical, or logistic support: A. Coulston, L. Chatterjee.

Collection and assembly of data: C.D. Gardner, L. Chatterjee, A. Rigby.

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