Whole-grain and blood lipid changes in apparently healthy adults: a systematic review and meta-analysis of randomized controlled studies

Am J Clin Nutr. 2015 Sep;102(3):556-72. doi: 10.3945/ajcn.115.109165. Epub 2015 Aug 12.


Background: Whole grains are recognized for their potential role in preventing cardiovascular diseases; however, results from randomized controlled studies on blood lipids are inconsistent, potentially because of compositional differences between individual grain types for some nutrients, including dietary fiber.

Objective: Using a meta-analytic approach, we assessed the effect of whole-grain compared with non-whole-grain foods on changes in total cholesterol (TC), LDL cholesterol, HDL cholesterol, and triglycerides.

Design: We conducted a systematic literature search in selected databases. Studies were included if they were randomized controlled comparisons between whole-grain foods and a non-whole-grain control in adults. A total of 6069 articles were screened for eligibility, and data were extracted from 24 studies. Weighted mean differences were calculated, and meta-regression analyses were performed for whole-grain dose, study duration, and baseline TC concentration.

Results: Overall, whole-grain intake lowered LDL cholesterol (weighted difference: -0.09 mmol/L; 95% CI: -0.15, -0.03 mmol/L; P < 0.01) and TC (weighted difference: -0.12 mmol/L; 95% CI: -0.19, -0.05 mmol/L; P < 0.001) compared with the control. Whole-grain oat had the greatest effect on TC (weighted difference: -0.17 mmol/L; 95% CI: -0.10, -0.25 mmol/L; P < 0.001). No effect of whole-grain foods on HDL cholesterol was seen, whereas whole-grain foods tended to lower triglycerides compared with the control (weighted difference: -0.04 mmol/L; 95% CI: -0.08, 0.01; P = 0.10). No association was found between whole-grain dose or baseline TC concentration and any of the outcomes, whereas study duration was positively associated with changes in TC and LDL cholesterol.

Conclusions: Consumption of whole-grain diets lowers LDL cholesterol and TC, but not HDL cholesterol or triglycerides, compared with consumption of non-whole-grain control diets. Whole-grain oat appears to be the most effective whole grain for lowering cholesterol.

Keywords: LDL cholesterol; cardiovascular disease; cereals; dietary fiber; lipidemia; total cholesterol; whole grains.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Adult
  • Cholesterol, HDL / blood*
  • Cholesterol, LDL / blood*
  • Diet
  • Dietary Fiber / administration & dosage
  • Humans
  • Randomized Controlled Trials as Topic
  • Sensitivity and Specificity
  • Triglycerides / blood*
  • Whole Grains / chemistry*


  • Cholesterol, HDL
  • Cholesterol, LDL
  • Dietary Fiber
  • Triglycerides