The Benefits of Fiber: How it Helps With Digestion

High fiber diets have numerous reported health benefits. It is a widely recommended healthy diet. Here are some health benefits high fiber diets have been associated with^{1,2,3,4,5,6,7,8}:

• reduced risk of type 2 diabetes
• reduced risk of certain forms of cancer
• reduced risk of obesity/enhanced weight control
• reduced risk of stroke
• reduced risk of cardiovascular, coronary heart, and respiratory disease
• lower serum cholesterol concentrations
• reduced blood pressure
• improved gastrointestinal function

Scientific research shows high-fiber foods enable butyrate-producing bacteria to thrive¹. Butyrate is a short chain fatty acid which is most commonly produced via fermenting fiber by bacteria in the colon⁹. Cells in the colon use butyrate as their primary source of energy¹⁰.

Butyrates have been shown to:

• Help neurons grow and survive^{11,12,13,14,15,16,17,18,19,20,21,22,23,24}. Neurons transmit information throughout the body and tell muscles, joints, and organs what to do
• Resist oxidative stress, which will help the body detoxify harmful chemicals^{21,23,25 ,26}
• Increase expression of learning-associated genes^27,28, which can help improve memory function

A specific type of fiber is inulin. Inulin is a prebiotic fiber that helps nourish beneficial bacteria in your gut. Inulin helps reduce blood glucose and oxidative stress^29,30. Inulin helps reduce body weight and improves glycemic control and antioxidant levels in type 2 diabetes patients³¹. Inulin can also increase colonic short-chain fatty acid production, which may reduce type 2 diabetes risk³².

These are some of the scientifically proven benefits of fiber. Two large prospective cohort studies (with a combined 1.5 million participants) found higher fiber diets were linked to a lower risk of death^8,33,34.

Fiber can be found in beans, whole grains, brown rice, nuts, berries, and many other sources. To easily get 2500 mg of fiber, including inulin, and 25 servings of fruit and vegetables daily

References:

1. Bourassa, M. W., Alim, I. R., Ratan, R. J., & Bultman, S. (2015). Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health? Neuroscience Letters, 2016, Vol. 625, 56-63.
2. Anderson, James W., Smith, Belinda M., & Gustafson, Nancy J. (1994). Health benefits and practical aspects of high-fiber diets. American Journal of Clinical Nutrition, 59(5), 1242S.
3. De Koning, L., & Hu, F. (2011). Do the health benefits of dietary fiber extend beyond cardiovascular disease? Archives of Internal Medicine, 171(12), 1069-70.
4. Pereira, M.A., O’Reilly, E., Augustsson, K., et al. Dietary fiber and risk of coronary heart disease: a pooled analysis of cohort studies. Arch Intern Med, 2004;164 (4) 370- 376.
5. Brown, L., Rosner, B., Willett, W.W., Sacks, F.M. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr, 1999;69 (1) 30- 42.
6. Schulze, M.B., Schulz, M. Heidemann, C., Schienkiewitz, A., Hoffmann, K., Boeing, H. Fiber and magnesium intake and incidence of type 2 diabetes: a prospective study and meta-analysis. Arch Intern Med, 2007;167 (9) 956- 965.
7. Whelton, S.P., Hyre, A.D., Pedersen, B., Yi, Y.,Whelton, P.K., He, J. Effect of dietary fiber intake on blood pressure: a meta-analysis of randomized, controlled clinical trials. J Hypertens, 2005;23 (3) 475- 481.
8. Park, Y., Subar, A., Hollenbeck, A., & Schatzkin, A. (2011). Dietary fiber intake and mortality in the NIH-AARP diet and health study.Archives of Internal Medicine, 171(12), 1061-8.
9. S.E. Pryde, S.H. Duncan, G.L. Hold, C.S. Stewart, H.J. Flint. The microbiology of butyrate formation in the human colon. FEMS Microbiol. Lett., 217 (2002), pp. 133–139.
10. W.E. Roediger. Role of anaerobic bacteria in the metabolic welfare of the colonic mucosa in man. Gut, 21 (1980), pp. 793–798.
11. T. Barichello, J.S. Generoso, L.R. Simões, C.J. Faller, R.A. Ceretta, F. Petronilho, et al. Sodium butyrate prevents memory impairment by Re-establishing BDNF and GDNF expression in experimental pneumococcal meningitis. Mol. Neurobiol., 52 (2015), pp. 734–740.
12. Y. Suzuki-Mizushima, E. Gohda, T. Okamura, K. Kanasaki, I. Yamamoto. Enhancement of NGF- and cholera toxin-induced neurite outgrowth by butyrate in PC12 cells. Brain Res., 951 (2002), pp. 209–217.
13. X. Wu, P.S. Chen, S. Dallas, B. Wilson, M.L. Block, C.-C. Wang, et al. Histone deacetylase inhibitors up-regulate astrocyte GDNF and BDNF gene transcription and protect dopaminergic neurons. Int. J. Neuropsychopharmacol., 11 (2008), pp. 1123–1134.
14. A.L. Mahan, L. Mou, N. Shah, J.-H. Hu, P.F. Worley, K.J. Ressler. Epigenetic modulation of Homer1a transcription regulation in amygdala and hippocampus with pavlovian fear conditioning. J. Neurosci., 32 (2012), pp. 4651–4659.
15. Y. Wei, P.A. Melas, G. Wegener, A.A. Mathé, C. Lavebratt. Antidepressant-like effect of sodium butyrate is associated with an increase in TET1 and in 5-hydroxymethylation levels in the Bdnf gene. Int. J. Neuropsychopharmacol., 18 (2015), pp. 1–10.
16. R.B. Varela, S.S. Valvassori, J. Lopes-Borges, E. Mariot, G.C. Dal-Pont, R.T. Amboni, et al. Sodium butyrate and mood stabilizers block ouabain-induced hyperlocomotion and increase BDNF, NGF and GDNF levels in brain of Wistar rats. J. Psychiatry Res., 61 (2015), pp. 114–121.
17. S.S. Valvassori, R.B. Varela, C.O. Arent, G.C. Dal-Pont, T.S. Bobsin, J. Budni, et al. Sodium butyrate functions as an antidepressant and improves cognition with enhanced neurotrophic expression in models of maternal deprivation and chronic mild stress. Curr. Neurovasc. Res., 11 (2014), pp. 359–366.
18.K.A. Intlekofer, N.C. Berchtold, M. Malvaez, A.J. Carlos, S.C. McQuown, M.J. Cunningham, et al. Exercise and sodium butyrate transform a subthreshold learning event into long-term memory via a brain-derived neurotrophic factor-dependent mechanism. Neuropsychopharmacology, 38 (2013), pp. 2027–2034.
19. R.J. Ferrante, J.K. Kubilus, J. Lee, H. Ryu, A. Beesen, B. Zucker, et al. Histone deacetylase inhibition by sodium butyrate chemotherapy ameliorates the neurodegenerative phenotype in huntington’s disease mice. J. Neurosci., 23 (2003), pp. 9418–9427.
20.G. Gardian, S.E. Browne, D.-K. Choi, P. Klivenyi, J. Gregorio, J.K. Kubilus, et al. Neuroprotective effects of phenylbutyrate in the N171-82Q transgenic mouse model of Huntington’s disease. J. Biol. Chem., 280 (2005), pp. 556–563.
21. B. Langley, M.A. D’Annibale, K. Suh, I. Ayoub, A. Tolhurst, B. Bastan, et al. Pulse inhibition of histone deacetylases induces complete resistance to oxidative death in cortical neurons without toxicity and reveals a role for cytoplasmic p21(waf1/cip1) in cell cycle-independent neuroprotection. J. Neurosci., 28 (2008), pp. 163–176.
22.H.J. Kim, D.-M. Chuang. HDAC inhibitors mitigate ischemia-induced oligodendrocyte damage: potential roles of oligodendrogenesis, VEGF, and anti-inflammation. Am. J. Transl. Res., 6 (2014), pp. 206–223.
23. Z. Wang, Y. Leng, L.-K. Tsai, P. Leeds, D.-M. Chuang. Valproic acid attenuates blood-brain barrier disruption in a rat model of transient focal cerebral ischemia: the roles of HDAC and MMP-9 inhibition. J. Cereb. Blood Flow Metab., 31 (2011), pp. 52–57.
24.H.J. Kim, M. Rowe, M. Ren, J.-S. Hong, P.-S. Chen, D.-M. Chuang. Histone deacetylase inhibitors exhibit anti-inflammatory and neuroprotective effects in a rat permanent ischemic model of stroke: multiple mechanisms of action. J. Pharmacol. Exp. Ther., 321 (2007), pp. 892–901.
25. H. Ryu, J. Lee, B.A. Olofsson, A. Mwidau, A. Dedeoglu, M. Escudero, et al. Histone deacetylase inhibitors prevent oxidative neuronal death independent of expanded polyglutamine repeats via an Sp1-dependent pathway. Proc. Natl. Acad. Sci. U. S. A., 100 (2003), pp. 4281–4286.
26.S. Camelo, A.H. Iglesias, D. Hwang, B. Due, H. Ryu, K. Smith, et al. Transcriptional therapy with the histone deacetylase inhibitor trichostatin A ameliorates experimental autoimmune encephalomyelitis. J. Neuroimmunol., 164 (2005), pp. 10–21.
27. N. Govindarajan, R.C. Agis-Balboa, J. Walter, F. Sananbenesi, A. Fischer. Sodium butyrate improves memory function in an Alzheimer’s disease mouse model when administered at an advanced stage of disease progression. J. Alzheimers Dis., 26 (2011), pp. 187–197.
28.M. Kilgore, C.A. Miller, D.M. Fass, K.M. Hennig, S.J. Haggarty, J.D. Sweatt, et al. Inhibitors of class 1 histone deacetylases reverse contextual memory deficits in a mouse model of Alzheimer’s disease. Neuropsychopharmacology, 35 (2010), pp. 870–880.
29.Zary-Sikorska E, Juskiewicz J. Effect of fructans with different degrees of polymerization on bacterial enzymes activity, lipid profile and antioxidant status in rats. Pol J Food Nutr Sci.2008;58:269–272.
30.Kozmus CE, Moura E, Serrao MP, Real H, Guimaraes JT, Guedes-de-Pinho P, Duarte BP, Marques F, Martins MJ, Vieira-Coelho MA. Influence of dietary supplementation with dextrin or oligofructose on the hepatic redox balance in rats. Mol Nutr Food Res. 2011;55:1735–1739.
31.Pourghassem Gargari, B., Dehghan, P., Aliasgharzadeh, A., & Asghari Jafar-abadi, M. (2013). Effects of High Performance Inulin Supplementation on Glycemic Control and Antioxidant Status in Women with Type 2 Diabetes. Diabetes & Metabolism Journal, 37(2), 140-148.
32.Wolever, Thomas M.S. (2010). The fermentable fibre inulin increases postprandial serum short-chain fatty acids and reduces free-fatty acids and ghrelin in healthy subjects. Applied Physiology, 35(1), 9-16.
33.Lehman, S. (2015, January 12). Higher-Fiber Diet Linked to Lower Risk of Death.
34.Yang, Y., Zhao, L., Wu, Q., Ma, X., & Xiang, Y. (2015). Association Between Dietary Fiber and Lower Risk of All-Cause Mortality: A Meta-Analysis of Cohort Studies. American Journal Of Epidemiology, 181(2), 83-91.
Journal Of Epidemiology, 181(2), 83-91.