New Study Finds High-fiber Diet Brings Significant Changes to Human Gut Microbiome

[6:52] What preceded this study that led to it being carried out?

• The study where a group from South Africa and a group from the US switched diets for 2 weeks.
• The group from the US inherently ate more fiber and had lowered markers of colon cancer.

[9:18]  How much fiber is a reasonably good amount?

• The RDA for men is 35 g/day and for women is 25g/day, but in the aforementioned study, the amount of fiber was 70g/day and showed benefits.

[11:55] Study design

• 10 week study.
• Student cohort
• 50g fiber/day
• Real high fiber food, not supplemental fiber.

[13:30] Results.

• Each subject’s changes were different.
• There were no large changes in diversity of the microbiome.
• Bifido bacteria were generally increased.
• Whiteson speculates that a longer timeframe would show larger changes.

[19:20] Does fiber provide an evolutionary benefit, or is it just a necessity of today’s sick population?

• Without fiber, bifido bacteria cannot excrete short chain fatty acids, such as butyrate, which is very important for healing the gut lining.
• As with any substance that you ingest, it is not good or bad. There is a duality in the response to its consumption. The devil is in the dose.

[22:02] What about supplemental fiber?

• They provide a very small diversity of fiber. The bacteria in your gut are designed to thrive on various different forms of fiber (some of which may not be found in any supplement).
• Those that ate more than 30 different types of plants per week were found to have a higher gut diversity.
• They may be better than nothing at all.
• Naturally occurring fiber is probably better.

[24:12] Diet must be individual.

• There are cases in which fiber can be detrimental.
• FODMAP diet works on this principle.

[25:48] Soluble vs. insoluble.

• Soluble is a bit more accessible to breakdown.
• You most likely want both types.

[27:28] What about those that follow the carnivore diet?

• Psyllium husks or another plant-based fiber supplement may be beneficial for them.

[32:41] Suspended animation of certain microbes.

• Deviation from a new strict diet can void the results due to this phenomenon.
• Industrialization has changed the microbe diversity of guts.

[36:30] Is anyone looking into mapping and tagging out the entire microbiome and what an “ideal” microbiome looks like?

[38:32] Are there any recommended timing or dosage of dietary fiber in people with IBS?

• Elimination diets and meticulous recording should allow you to determine which types of fiber that will agree with you.

[40:04] Why would my ancestors eat roots and leaves when they could just eat meat?

• “Ancestors” does not just refer to prehistoric ancestors. What 5-6 generations back ate will shape your microbiome.
• There are various records of different tribes eating fibers for sanitation purposes as well as other health benefits.
• Occasional hard times probably made it a necessity to eat fiber from time to time just to survive.
• Also, don’t assume that every ancestor was adept at killing animals for meat.

[49:16] Surprising findings?

• Many of the college students weren’t very learned on what foods are high in fiber.
• Avocados and berries are fairly high in fiber.

[51:46] Successful cancer treatment is correlated with the gut microbiome.

• These microbiomes can be transferred via fecal transplant.

[53:12] MAP bacterium and its association with Crohn’s disease.

[57:22] The importance of easing into a protocol and giving it time to work.