A claim you hear on longevity podcasts
The claim checked: Fiber cuts colon cancer risk by up to a third and heart disease by up to 40% Hear it at 3:00
Most of the ten studies tie more fiber to lower colorectal and heart disease risk, by 9% to 31% in pooled data; two cohorts found no colorectal link.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
“it's been shown to reduce the risk of colon cancer by as much as a third and breast cancer by almost 40% it also lowers cholesterol and reduces the risk of heart disease by as much as 40%”
pooled analysis · 2010
“Intake of dietary fiber is inversely associated with colorectal cancer risk.”
Dietary fiber and colorectal cancer risk: a nested case-control study using food diaries. J Natl Cancer Inst
Who: UK adults from seven prospective cohorts (UK Dietary Cohort Consortium) with 4- to 7-day food diaries; incident colorectal cancer cases and matched cancer-free controls
PMID 20407088
pooled analysis · 2019 · landmark
“The observational data in table 1 show that higher intakes of total dietary fibre are associated with a 15–31% reduction in the risk of specified critical outcomes.”
Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet
Who: adults without chronic disease in prospective cohorts and randomised trials
PMID 30638909
systematic review · 2018 · landmark
“In our study, even though 85% of the associations were significant, a higher intake of dietary fibers was convincingly associated only with a decreased likelihood of early mortality and CVD (including coronary artery disease and specific-cause mortality).”
Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta-analyses. Am J Clin Nutr
Who: umbrella review of 18 meta-analyses of observational studies in adults (general and mixed populations)
PMID 29566200
controlled trial · 2020
“SFs were associated with a decreased risk of CVD [HR: 0.80 (0.66, 0.98); P-trend = 0.01] and colorectal cancer [HR: 0.41 (0.21, 0.79); P-trend = 0.01].”
Associations between consumption of dietary fibers and the risk of cardiovascular diseases, cancers, type 2 diabetes, and mortality in the prospective NutriNet-Santé cohort. Am J Clin Nutr
Who: French adults aged 18+ in the web-based NutriNet-Santé cohort (78.7% women, mean age 42.8)
PMID 32369545
pooled analysis · 2013 · landmark
“A significantly lower risk of 9% was seen for both CVD and CHD with every additional 7 g/day of total fibre consumed.”
Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ
Who: Generally healthy adults in 22 prospective cohort studies from the US, Europe, Japan and Australia (studies recruiting people for ill health excluded)
PMID 24355537
trial or observed group · 2012
“This association was attenuated after multivariable adjustment, but a statistically significant 17% lower risk (95% CI: 0.72–0.96; P-trend 0.013) remained.”
Dietary fibre intake and risks of cancers of the colon and rectum in the European prospective investigation into cancer and nutrition (EPIC). PLoS One
Who: 477,312 EPIC participants (335,062 women, 142,250 men) from 10 European countries, mostly aged 35 and over, free of cancer at enrolment
PMID 22761771
pooled analysis · 2018
“The pooled odds ratios of DCC indicated that the risk of DCC among individuals with the highest dietary fiber intake was 21% lower than that among individuals with the lowest dietary fiber intake (RR = 0.79, 95%CI = 0.71–0.87), again with low heterogeneity ( I 2 = 28.8%; P = .163; Fig. 3 ).”
Dietary fiber intake and risks of proximal and distal colon cancers: A meta-analysis. Medicine (Baltimore)
Who: 11 prospective cohort studies (7 US, 4 Europe) of dietary fiber intake and proximal/distal colon cancer
PMID 30200062
pooled analysis · 2011
“Our results indicate a 10% reduction in risk of colorectal cancer for each 10 g/day intake of total dietary fibre and cereal fibre and a about a 20% reduction for each three servings (90 g/day) of whole grain daily, and further reductions with higher intake.”
Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies. BMJ
Who: prospective cohort studies of adults (US, Europe, Asia) on dietary fibre/whole grain intake and colorectal cancer incidence
PMID 22074852
other primary study · 2005
“However, after accounting for other dietary risk factors, high dietary fiber intake was not associated with a reduced risk of colorectal cancer.”
Dietary fiber intake and risk of colorectal cancer: a pooled analysis of prospective cohort studies. JAMA
Who: 725,628 men and women in 13 prospective cohort studies (Pooling Project of Prospective Studies of Diet and Cancer), North America and Europe
PMID 16352792
other primary study · 2007
“Total dietary fiber intake was not associated with colorectal cancer.”
Dietary fiber and whole-grain consumption in relation to colorectal cancer in the NIH-AARP Diet and Health Study. Am J Clin Nutr
Who: 489,611 US adults aged 50-71 (291,988 men, 197,623 women) in the NIH-AARP Diet and Health Study, without cancer at baseline
PMID 17490973
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