Not all dietary fibers are created equal

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Dietary fibers, found naturally in fruits, vegetables, nuts, and grains, have long been heralded for their myriad health benefits.

However, new research led by Professor Michael Snyder at Stanford University reveals that not all dietary fibers behave the same way in the body, with some even causing inflammation and liver damage.

Study Methodology: Inulin vs Arabinoxylan

The study focused on the effects of two commonly consumed dietary fibers: inulin and arabinoxylan. Researchers monitored the metabolisms and microbiomes of healthy volunteers who consumed varying amounts of these fibers.

The study involved analyzing molecular profiles, gut bacteria, and other markers of metabolic changes over a period of three 3-week sessions, with breaks in between.

Key Findings: A Mixed Bag of Effects

  1. Arabinoxylan: This fiber appeared beneficial for reducing LDL, the “bad” cholesterol.
  2. Inulin: At higher doses, inulin led to inflammation in some participants.
  3. Individual Variability: Participants had widely varying responses to the fibers, suggesting a need for personalized dietary plans.
  4. Role of Gut Bacteria: High fiber consumption led to an increase in bile acids derived from gut bacteria, which break down cholesterol, pointing to the microbiome’s important role in cholesterol management.

The Significance: Personalization and Caution

This study sheds light on both the pros and cons of dietary fiber intake:

Understanding Mechanisms: It provides insights into how fibers like arabinoxylan can lower cholesterol levels.

Potential Risks: It alerts us to the potential downsides of certain fibers like inulin, which in high doses may lead to inflammation.

Personalized Nutrition: The study’s findings support the notion that dietary interventions could and should be tailored to individual metabolic responses and needs.

Future Research

Researchers aim to use this data to develop personalized diets tailored to individual fiber responses.

The study was supported by the Stanford Center for Genomics and Personalized Medicine Sequencing Center and the National Institutes of Health.

Further Reading

For those interested in nutrition, you may also want to read about how the Mediterranean diet could protect brain health or the best time to take vitamins to prevent heart disease.

For more general health information, studies on plant nutrients that can help reduce high blood pressure and antioxidants that might reduce the risk of dementia may also be of interest.

The full study is available in the journal Cell Host & Microbe.


While dietary fibers remain an important part of a balanced diet, this study highlights the need for a more nuanced approach to their consumption.

As science moves towards a more personalized understanding of nutrition, findings like these serve as important milestones in tailoring diets to individual health needs.

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