JeffN wrote:For the record, over 97% of Americans, including vegetarians, exceed the RDA for protein with the average intake being double the RDA. However, 97% of Americans fall short of the recommended intake of fiber, with the average intake being about 1/2 the RDA. Considering animal foods contain no fiber, I would consider that a serious and important health issue.
Speaking of the importance of fiber...
1) Dietary fiber intake and mortality in the NIH-AARP diet and health study.Park Y, Subar AF, Hollenbeck A, Schatzkin A.
Arch Intern Med. 2011 Jun 27;171(12):1061-8. doi: 10.1001/archinternmed.2011.18. Epub 2011 Feb 14.
PMID:21321288
Free PMC Article
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3513325/http://www.ncbi.nlm.nih.gov/pmc/article ... 414391.pdfAbstract
BACKGROUND: Dietary fiber has been hypothesized to lower the risk of coronary heart disease, diabetes, and some cancers. However, little is known of the effect of dietary fiber intake on total death and cause-specific deaths.
METHODS: We examined dietary fiber intake in relation to total mortality and death from specific causes in the NIH (National Institutes of Health)-AARP Diet and Health Study, a prospective cohort study. Diet was assessed using a food-frequency questionnaire at baseline. Cause of death was identified using the National Death Index Plus. Cox proportional hazard models were used to estimate relative risks and 2-sided 95% confidence intervals (CIs).
RESULTS: During an average of 9 years of follow-up, we identified 20 126 deaths in men and 11 330 deaths in women. Dietary fiber intake was associated with a significantly lowered risk of total death in both men and women (multivariate relative risk comparing the highest with the lowest quintile, 0.78 [95% CI, 0.73-0.82; P for trend, <.001] in men and 0.78 [95% CI, 0.73-0.85; P for trend, <.001] in women). Dietary fiber intake also lowered the risk of death from cardiovascular, infectious, and respiratory diseases by 24% to 56% in men and by 34% to 59% in women. Inverse association between dietary fiber intake and cancer death was observed in men but not in women. Dietary fiber from grains, but not from other sources, was significantly inversely related to total and cause-specific death in both men and women.
CONCLUSIONS: Dietary fiber may reduce the risk of death from cardiovascular, infectious, and respiratory diseases. Making fiber-rich food choices more often may provide significant health benefits.
2) Dietary Fiber Prevents Both Morbidity and Mortality From Respiratory DiseaseLesley M. Butler, PhD; Haidong Kan, MD; Stephanie J. London, MD, DrPH
Arch Intern Med. 2011;171(12):1123. doi:10.1001/archinternmed.2011.240.
http://archinte.jamanetwork.com/article ... eid=487088 3) Do the Health Benefits of Dietary Fiber Extend Beyond Cardiovascular Disease?Comment on “Dietary Fiber Intake and Mortality in the NIH-AARP Diet and Health Study”
Arch Intern Med. 2011;171(12):1069-1070. doi:10.1001/archinternmed.2011.19.
http://archinte.jamanetwork.com/article ... eid=227509 4) Dietary fiber intake and risk of breast cancer: a meta-analysis of prospective cohort studies. Dong JY1, He K, Wang P, Qin LQ.Am J Clin Nutr. 2011 Sep;94(3):900-5. doi: 10.3945/ajcn.111.015578. Epub 2011 Jul 20.
Abstract
BACKGROUND:
Observational and preclinical studies suggest that dietary fiber intake may reduce the risk of breast cancer, but the results are inconclusive.
OBJECTIVE:
We aimed to examine the association between dietary fiber intake and risk of breast cancer by conducting a meta-analysis of prospective cohort studies.
DESIGN:
Relevant studies were identified by a PubMed database search through January 2011. Reference lists from retrieved articles were also reviewed. We included prospective cohort studies that reported RRs with 95% CIs for the association between dietary fiber intake and breast cancer risk. Both fixed- and random-effects models were used to calculate the summary risk estimates.
RESULTS:
We identified 10 prospective cohort studies of dietary fiber intake and risk of breast cancer involving 16,848 cases and 712,195 participants. The combined RR of breast cancer for the highest compared with the lowest dietary fiber intake was 0.89 (95% CI: 0.83, 0.96), and little evidence of heterogeneity was observed. The association between dietary fiber intake and risk of breast cancer did not significantly differ by geographic region, length of follow-up, or menopausal status of the participants. Omission of any single study had little effect on the combined risk estimate. Dose-response analysis showed that every 10-g/d increment in dietary fiber intake was associated with a significant 7% reduction in breast cancer risk. Little evidence of publication bias was found.
CONCLUSION:
This meta-analysis provides evidence of a significant inverse dose-response association between dietary fiber intake and breast cancer risk.
5) Dietary fiber intake and stroke risk: a meta-analysis of prospective cohort studies. Chen GC1, Lv DB, Pang Z, Dong JY, Liu QF. Eur J Clin Nutr. 2013 Jan;67(1):96-100. doi: 10.1038/ejcn.2012.158. Epub 2012 Oct 17.
Abstract
BACKGROUND/OBJECTIVES:
Epidemiological studies have suggested that dietary fiber intake may be associated with a decreased risk of stroke, but the findings have been inconsistent. We aimed to assess this association by conducting a meta-analysis of prospective cohort studies.
SUBJECTS/METHODS:
We performed a literature search on PubMed database through July 2012 to identify prospective studies of dietary fiber intake in relation to risk of stroke. We also comprehensively reviewed the reference lists of the retrieved articles to identify additional studies. We used a random-effects model to compute the summary risk estimates.
RESULTS:
Six prospective cohort studies containing a total of 314 864 subjects and 8920 stroke cases were included. The summary relative risk (RR) of stroke for the highest vs lowest category of dietary fiber intake was 0.87 (95% confidence interval (CI), 0.77-0.99). The corresponding RR in the subgroup analyses for men and women was 0.95 (95% CI, 0.83-1.08) and 0.80 (95% CI, 0.66-0.96), respectively; and for ischemic stroke and hemorrhagic stroke was 0.83(95% CI, 0.72-0.96) and 0.86 (95% CI, 0.70-1.06), respectively. Meta-regression indicated no significant difference between gender (P-interaction=0.18), or stroke subtypes (P-interaction =0.85). The dose-response analysis suggested a 12% (RR=0.88; 95% CI, 0.79-0.97) reduction in risk of stroke for each 10 g per day increment in dietary fiber intake. Moderate heterogeneity emerged in some of analyses, but disappeared after removing one study substantially contributing to the heterogeneity. Little evidence of publication bias was detected.
CONCLUSION:
Findings of this meta-analysis indicate a significant inverse dose-response relationship between dietary fiber intake and risk of stroke.
6) Association between dietary fiber intake and risk of coronary heart disease: A meta-analysis. Wu Y1, Qian Y2, Pan Y2, Li P1, Yang J1, Ye X3, Xu G4. Clin Nutr. 2014 May 28. pii: S0261-5614(14)00140-X. doi: 10.1016/j.clnu.2014.05.009. [Epub ahead of print]
http://www.ncbi.nlm.nih.gov/pubmed/24929874Abstract
BACKGROUND & AIMS:
The association between coronary heart disease (CHD) and dietary fiber intake is not consistent, especially for the subtypes of dietary fiber. The aim of our study was to conduct a meta-analysis of existing cohort published studies assessing the association between dietary fiber intake and risk of CHD, and quantitatively estimating their dose-response relationships.
METHODS:
We searched PubMed and EMBASE before May 2013. Random-effect model was used to calculate the pool relative risk (RRs) for the incidence and mortality of CHD. Dose-response, subgroup analyses based on fiber subtypes, heterogeneity and publication bias were also carried out.
RESULTS:
Eighteen studies involving 672,408 individuals were finally included in the present study. The pooled-adjusted RRs of coronary heart disease for the highest versus lowest category of fiber intake were 0.93 (95% confidence interval (CI), 0.91-0.96, P < 0.001) for incidence of all coronary events and 0.83 (95% CI, 0.76-0.91, P < 0.001) for mortality. Further subgroup analyses based on fiber subtypes (cereal, fruit, and vegetable fiber), indicated that RRs were 0.92 (95% CI, 0.85-0.99, P = 0.032), 0.92 (95% CI, 0.86-0.98, P = 0.01), 0.95 (95% CI, 0.89-1.01, P = 0.098) respectively for all coronary event and 0.81 (95% CI, 0.72-0.92, P = 0.001), 0.68 (95% CI, 0.43-1.07, P = 0.094), 0.91 (95% CI, 0.74-1.12, P = 0.383) for mortality. In addition, a significant dose-response relationship was observed between fiber intake and the incidence and mortality of CHD (P < 0.001).
CONCLUSIONS:
Our results indicate that consumption of dietary fiber is inversely associated with risk of coronary heart disease, especially for fiber from cereals and fruits. Besides, soluble and insoluble fibers have the similar effect. A significant dose-response relationship is also observed between fiber intake and CHD risk.
7) Dietary Fiber Intake and Total Mortality: A Meta-Analysis of Prospective Cohort Studies.Kim Y, Je Y.
Am J Epidemiol. 2014 Aug 20. pii: kwu174. [Epub ahead of print]
PMID:25143474
http://www.ncbi.nlm.nih.gov/pubmed/25143474Abstract
Greater intake of dietary fiber has been associated with lower risk of several chronic diseases. Some observational studies have examined the association between dietary fiber intake and total mortality, but the results were inconclusive.
We conducted a meta-analysis of data from prospective cohort studies to quantitatively assess the association.
Eligible studies were identified by searching the PubMed and Embase databases for all articles published through November 30, 2013, and by reviewing the reference lists of retrieved articles. Study-specific estimates adjusting for potential confounders were combined to calculate a pooled relative risk and 95% confidence interval using a random-effects model.
Seven prospective cohort studies of dietary fiber intake and total mortality, including 62,314 deaths among 908,135 participants, were identified.
The pooled adjusted relative risk of total mortality for the highest category of dietary fiber intake versus the lowest was 0.77 (95% confidence interval: 0.74, 0.80). In a dose-response meta-analysis, the pooled adjusted relative risk for a 10-g/day increment of dietary fiber intake was 0.89 (95% confidence interval: 0.85, 0 92). By source of fiber, cereal and, to a lesser extent, vegetable fiber were significantly associated with lower total mortality, while fruit fiber showed no association.
In conclusion, high dietary fiber intake may reduce the risk of total mortality.
8 ) Dietary Fiber, Kidney Function, Inflammation, and Mortality Risk.Clin J Am Soc Nephrol. 2014 Oct 3. pii: CJN.02260314. [Epub ahead of print]
PMID:25280496
http://www.ncbi.nlm.nih.gov/pubmed/25280496/?
Abstract
BACKGROUND AND OBJECTIVES: In the United States population, high dietary fiber intake has been associated with a lower risk of inflammation and mortality in individuals with kidney dysfunction. This study aimed to expand such findings to a Northern European population.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Dietary fiber intake was calculated from 7-day dietary records in 1110 participants aged 70-71 years from the Uppsala Longitudinal Study of Adult Men (examinations performed during 1991-1995). Dietary fiber was adjusted for total energy intake by the residual method. Renal function was estimated from the concentration of serum cystatin C, and deaths were registered prospectively during a median follow-up of 10.0 years.
RESULTS: Dietary fiber independently and directly associated with eGFR (adjusted difference, 2.6 ml/min per 1.73 m2 per 10 g/d higher; 95% confidence interval [95% CI], 0.3 to 4.9). The odds of C-reactive protein >3 mg/L were lower (linear trend, P=0.002) with higher fiber quartiles. During follow-up, 300 participants died (incidence rate of 2.87 per 100 person-years at risk). Multiplicative interactions were observed between dietary fiber intake and kidney dysfunction in the prediction of mortality. Higher dietary fiber was associated with lower mortality in unadjusted analysis. These associations were stronger in participants with kidney dysfunction (eGFR<60 ml/min per 1.73 m2) (hazard ratio [HR], 0.58; 95% CI, 0.35 to 0.98) than in those without (HR, 1.30; 95% CI, 0.76 to 2.22; P value for interaction, P=0.04), and were mainly explained by a lower incidence of cancer-related deaths (0.25; 95% CI, 0.10 to 0.65) in individuals with kidney dysfunction versus individuals with an eGFR=/>60 ml/min per 1.73 m2 (1.61; 95% CI, 0.69 to 3.74; P value for interaction, P=0.01).
CONCLUSIONS: High dietary fiber was associated with better kidney function and lower inflammation in community-dwelling elderly men from Sweden. High dietary fiber was also associated with lower (cancer) mortality risk, especially in individuals with kidney dysfunction.
UPDATE
9) Fiber intake and all-cause mortality in the Prevención con Dieta Mediterránea (PREDIMED) study.
Buil-Cosiales P, Zazpe I, Toledo E, Corella D, Salas-Salvadó J, Diez-Espino J, Ros E, Fernandez-Creuet Navajas J, Santos-Lozano JM, Arós F, Fiol M, Castañer O, Serra-Majem L, Pintó X, Lamuela-Raventós RM, Marti A, Basterra-Gortari FJ, Sorlí JV, Verdú-Rotellar JM, Basora J, Ruiz-Gutierrez V, Estruch R, Martínez-González MÁ.
Am J Clin Nutr. 2014 Dec;100(6):1498-507. doi: 10.3945/ajcn.114.093757. Epub 2014 Sep 10.
PMID:25411285
Abstract
BACKGROUND: Few observational studies have examined the effect of dietary fiber intake and fruit and vegetable consumption on total mortality and have reported inconsistent results. All of the studies have been conducted in the general population and typically used only a single assessment of diet.
OBJECTIVE: We investigated the association of fiber intake and whole-grain, fruit, and vegetable consumption with all-cause mortality in a Mediterranean cohort of elderly adults at high cardiovascular disease (CVD) risk by using repeated measurements of dietary information and taking into account the effect of a dietary intervention.
DESIGN: We followed up 7216 men (55-75 y old) and women (60-75 y old) at high CVD risk in the Prevención con Dieta Mediterránea (PREDIMED) trial for a mean of 5.9 y. Data were analyzed as an observational cohort. Participants were initially free of CVD. A 137-item validated food-frequency questionnaire administered by dietitians was repeated annually to assess dietary exposures (fiber, fruit, vegetable, and whole-grain intakes). Deaths were identified through the continuing medical care of participants and the National Death Index. An independent, blinded Event Adjudication Committee adjudicated causes of death. Cox regression models were used to estimate HRs of death during follow-up according to baseline dietary exposures and their yearly updated changes.
RESULTS: In up to 8.7 y of follow-up, 425 participants died. Baseline fiber intake and fruit consumption were significantly associated with lower risk of death [HRs for the fifth compared with the first quintile: 0.63 (95% CI: 0.46, 0.86; P = 0.015) and 0.59 (95% CI: 0.42, 0.82; P = 0.004), respectively]. When the updated dietary information was considered, participants with fruit consumption >210 g/d had 41% lower risk of all-cause mortality (HR: 0.59; 95% CI: 0.44, 0.78). Associations were strongest for CVD mortality than other causes of death.
CONCLUSION: Fiber and fruit intakes are associated with a reduction in total mortality.
10) Association between dietary fiber and lower risk of all-cause mortality: a meta-analysis of cohort studies.
Am J Epidemiol. 2015 Jan 15;181(2):83-91. doi: 10.1093/aje/kwu257. Epub 2014 Dec 31.
Yang Y, Zhao LG, Wu QJ, Ma X, Xiang YB.
http://www.ncbi.nlm.nih.gov/pubmed/25552267Abstract
Although in vitro and in vivo experiments have suggested that dietary fiber might have beneficial effects on health, results on the association between fiber intake and all-cause mortality in epidemiologic studies have been inconsistent. Therefore, we conducted a meta-analysis of prospective cohort studies to quantitatively assess this association. Pertinent studies were identified by searching articles in PubMed and Web of Knowledge through May 2014 and reviewing the reference lists of the retrieved articles. Study-specific risk estimates were combined using random-effects models. Seventeen prospective studies (1997-2014) that had a total of 67,260 deaths and 982,411 cohort members were included. When comparing persons with dietary fiber intakes in the top tertile with persons whose intakes were in the bottom tertile, we found a statistically significant inverse association between fiber intake and all-cause mortality, with an overall relative risk of 0.84 (95% confidence interval: 0.80, 0.87; I(2) = 41.2%). There was a 10% reduction in risk for per each 10-g/day increase in fiber intake (relative risk = 0.90; 95% confidence interval: 0.86, 0.94; I(2) = 77.2%). The combined estimate was robust across subgroup and sensitivity analyses. No publication bias was detected. A higher dietary fiber intake was associated with a reduced risk of death. These findings suggest that fiber intake may offer a potential public health benefit in reducing all-cause mortality.
Fiber consumption and all-cause, cardiovascular, and cancer mortalities: A systematic review and meta-analysis of cohort studies.
Mol Nutr Food Res. 2015 Jan;59(1):139-46. doi: 10.1002/mnfr.201400449. Epub 2014 Dec 11.
Abstract
The present meta-analysis aimed to investigate fiber consumption and all-cause mortality, and cause-specific mortality. MEDLINE and web of science database were searched for cohort studies published from inception to August 2014. Studies were included if they provided a hazard ratio (HR) and corresponding 95% CI for mortality in relation to fiber consumption.We found that, compared with those who consumed lowest fiber, for individuals who ate highest fiber, mortality rate was lower by 23% (HR, 0.77; 95% CI, 0.72-0.81) for CVD, by 17% (HR, 0.83; 95% CI, 0.74-0.91) for cancer, by 23% (HR, 0.77; 95% CI, 0.73-0.81) for all-cause mortality. For each 10 g/day increase in fiber intake, the pooled HR was estimated to be 0.89 (95% CI, 0.86-0.93) for all-cause mortality, 0.80 (95% CI, 0.72-0.88) for CHD mortality, and 0.66 (95% CI, 0.40-0.92) for IHD mortality, 0.91 (95% CI, 0.88-0.94) for cancer. Dietary fiber and CVD mortality showed a strong dose-response relation. Apparently, fiber consumption is inversely associated with all-cause mortality and CVD, IHD, cancer mortality.
In Health
Jeff