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The benefits of consuming a higher fiber diet have been consistently demonstrated in nutrition research. Epidemiology clearly shows that higher intakes, compared to lower intakes, leads to a risk reduction for a range of diseases, including cardiovascular disease and colon cancer.
And based on this epidemiological evidence, most dietary guidelines recommend dietary patterns that provide adults with 30-35g of dietary fiber per day.
However, what do we know about intakes beyond this?
Do we continue to see benefit in a linear fashion? Is there a ceiling to benefit? At what level would we see “optimal” benefit or the greatest magnitude of risk reduction?
The ability to answer such questions is hampered by the fact it’s difficult to find cohort studies where the “high” fiber level is high enough to relate to this issue. However, there have been some controlled studies looking specifically at “very high” intakes, i.e. those far above current recommendations. In addition, there are some populations where habitual dietary intake gives a fiber intake far above the typical intakes in Western cohorts.
So in this episode we go through this data to try to see what we can conclude about this fascinating question of ‘what are the health effects at very high fiber intakes?’
Co-hosts for this Episode
Dr. Alan Flanagan has a PhD in nutrition from the University of Surrey, where his doctoral research focused on circadian rhythms, feeding, and chrononutrition.
This work was based on human intervention trials. He also has a Masters in Nutritional Medicine from the same institution.
Dr. Flanagan is a regular co-host of Sigma Nutrition Radio. He also produces written content for Sigma Nutrition, as part of his role as Research Communication Officer.
Danny Lennon has a master’s degree (MSc.) in Nutritional Sciences from University College Cork, and he is the founder of Sigma Nutrition.
Danny is currently a member of the Advisory Board of the Sports Nutrition Association, the global regulatory body responsible for the standardisation of best practice in the sports nutrition profession.
- Epidemiology suggestive of benefit to more?
- Pereira et al., 2004
- Aune et al., 2011
- Reynolds et al., 2020
- Diet swap in African Americans & rural Africans
- Very high fiber & blood lipids
- Very high fiber & hyperlipidemia
- Very high fiber & diabetes
- Potential detrimental impacts of very high fiber
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- Studies mentioned in this episode:
- Pereira et al., 2004 – Dietary Fiber and Risk of Coronary Heart Disease
- Aune et al., 2011 – Dietary fibre, whole grains, and risk of colorectal cancer
- Reynolds et al., 2020 – Dietary fibre and whole grains in diabetes management: Systematic review and meta-analyses
- O’ Keefe et al., 2015 – Fat, Fiber and Cancer Risk in African Americans and Rural Africans
- Jenkins et al., 2001 – Effect of a very-high-fiber vegetable, fruit, and nut diet on serum lipids and colonic function
- Jenkins et al., 1993 – Effect on Blood Lipids of Very High Intakes of Fiber in Diets Low in Saturated Fat and Cholesterol
- Anderson & Ward, 1979 – High-carbohydrate, high-fiber diets for insulin-treated men with diabetes mellitus
- Receive detailed study notes (including breakdowns of these studies) for this episode by subscribing to Sigma Nutrition Premium.