Gut-Brain & Microbiome Learning Center · Module 9 of 12
Nutrition & the Microbiome
Introduces relationships researchers study among diet, nutrition and microbial communities. Educational only — not a treatment protocol.
Nutrition and the gut microbiome are closely connected areas of biology. What reaches the gastrointestinal tract helps shape the environment in which intestinal microorganisms live.
At the same time, microorganisms participate in the metabolism of some dietary components and produce substances that can interact with the body.
This relationship is one reason nutrition appears frequently in microbiome research. It does not mean that one diet produces one universal microbiome or that a particular diet has been established as a treatment for autism.
Food Also Feeds a Microbial Ecosystem
Human digestive enzymes do not completely break down every component of food. Some dietary substances reach intestinal microorganisms and can be used in microbial metabolism.
The legacy NVL research material specifically discusses microbial fermentation of nondigestible carbohydrates. This process can produce metabolites, including short-chain fatty acids.
Review Module 7 — Microbial MetabolitesNutrition Can Influence Microbial Communities
The legacy material identifies nutrition as one factor that can influence the composition of the gut microbiota across the lifespan. Microbial communities are dynamic. Changes in food patterns can alter the substances available to intestinal microorganisms.
However, microbiome composition is influenced by many factors. Nutrition is only one of them. Others discussed throughout this Learning Center include:
- age and development
- medications, including antibiotics
- environment
- gastrointestinal conditions
- individual biology
The Microbiome Also Participates in Nutrient Metabolism
The relationship works in both directions. The legacy source describes gut microorganisms as participating in the synthesis or metabolism of certain:
- nutrients
- vitamins
- hormones
- other biologically active compounds
It also discusses microbial production of metabolites through dietary fermentation. This means nutrition and microbial activity form an interacting system rather than a one-way process.
Short-Chain Fatty Acids
Short-chain fatty acids provide one example of the connection between diet and microbial metabolism. Microorganisms can ferment certain carbohydrates and produce compounds including:
- acetate
- propionate
- butyrate
As explored in Module 7, researchers study these metabolites in relation to intestinal physiology, metabolism, immune pathways and gut-brain communication. Different metabolites can have different effects depending on biological context.
Review Module 7 — Microbial MetabolitesNutrition, Microbes and Individual Differences
No two people have exactly the same microbial ecosystem. Individual microbial communities can differ in composition and function. That means two people consuming similar foods do not necessarily have identical microbiome responses.
Researchers must consider individual variation when studying relationships between nutrition and microbial activity.
Nutrition and Development
The legacy material discusses microbial communities changing across the lifespan as feeding patterns and environmental exposures change. Researchers are interested in these developmental changes because the microbiome and many human biological systems develop over time.
However, the existence of overlapping developmental periods does not prove that a particular food, feeding practice or microbial change causes autism.
Nutrition and Epigenetic Research
The legacy source also discusses nutrition as one environmental factor considered in epigenetic research. Epigenetics concerns biological processes that can influence patterns of gene activity without changing the underlying DNA sequence.
Researchers investigate how environmental factors, nutrients, microbial metabolites and other biological influences may interact with gene-regulatory processes. This is an evolving research area.
The existence of an epigenetic mechanism does not establish that a particular food turns an "autism gene" on or off.
What This Module Does Not Recommend
This Learning Center does not prescribe an autism diet. It does not recommend removing foods, adding supplements or making major dietary changes as a treatment for autism.
Nutrition can be especially complex when a child has:
- food allergies
- gastrointestinal conditions
- restricted food preferences
- feeding difficulties
- nutritional deficiencies
- other medical considerations
Individual dietary decisions should be considered in the appropriate professional context.
What We Know
Nutrition can influence the intestinal environment and the substrates available to gut microorganisms. Gut microorganisms participate in the metabolism of some dietary components.
Microbial fermentation can produce biologically active metabolites. The gut microbiome varies substantially among individuals.
What Researchers Are Studying
Researchers investigate relationships among:
- dietary patterns
- microbial communities
- microbial metabolites
- nutrient metabolism
- intestinal physiology
- immune signaling
- gene regulation
- gut-brain communication
Nutrition is one component of a much larger biological system.
What Remains Uncertain
There is no single diet established by the legacy material as producing an ideal microbiome for every person. The source material also does not establish that a particular dietary pattern treats or reverses autism.
Changes in diet can coincide with changes in the microbiome without proving that those microbial changes will produce a particular developmental outcome.