Whole grain consumption and human health: an umbrella review of observational studies

Int J Food Sci Nutr. 2020 Sep;71(6):668-677. doi: 10.1080/09637486.2020.1715354. Epub 2020 Jan 21.


Whole grains have been associated with a number of health benefits. We systematically reviewed existing meta-analyses of observational studies and evaluated the level of evidence for their putative effects based on pre-selected criteria. Of the 23 included studies, we found convincing evidence of an inverse association between whole grain consumption and risk of type-2 diabetes and colorectal cancer; possible evidence of decreased risk of colon cancer and cardiovascular mortality with increased whole grain intake, as well as increased risk of prostate cancer. Limited or insufficient evidence was available for all other outcomes investigated. Overall findings are encouraging for a positive effect of whole grain consumption on certain diseases, especially highly prevalent metabolic diseases, however, uncertainty of some negative associations deserves further attention.

Keywords: Whole grain; cohort; evidence; fibre; meta-analysis; umbrella review.

Publication types

  • Systematic Review

MeSH terms

  • Cardiovascular Diseases / prevention & control
  • Colonic Neoplasms / prevention & control
  • Colorectal Neoplasms / prevention & control
  • Diabetes Mellitus, Type 2 / prevention & control
  • Diet*
  • Dietary Fiber / administration & dosage*
  • Eating
  • Female
  • Health Status*
  • Humans
  • Male
  • Observational Studies as Topic*
  • Prostatic Neoplasms / epidemiology
  • Whole Grains*


  • Dietary Fiber