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Condition · Gastrointestinal

Small Intestinal Bacterial Overgrowth (SIBO)

Chronic bloating, abdominal pain, or “food baby” distention by day’s end aren’t normal — they’re tell-tale signs your small intestine may be hosting far more microbes than nature intended. Up to 70% of patients diagnosed with IBS actually have underlying SIBO, which is why our team prioritizes accurate testing and a precise, subtype-aware treatment plan rather than generic symptom management.

A young woman with the bloating and stomach pain typical of SIBO.

What Exactly Is SIBO?

SIBO stands for Small Intestinal Bacterial Overgrowth. It occurs when there’s an abnormal increase in bacteria in the small intestine, where bacterial levels should normally be much lower than in the large intestine. This overgrowth interferes with normal digestion and absorption, ferments carbohydrates into excess gas, and damages the intestinal lining — driving a cycle of bloating, pain, and unpredictable bowel patterns that often gets misdiagnosed as IBS.

Types of SIBO and Their Characteristics

SIBO is categorized by the type of gas produced during bacterial fermentation. Each subtype presents differently and requires its own treatment strategy — without the right subtype identification, care is generic and often ineffective.

SubtypeGas ProducedCommon SymptomsConsiderations
Hydrogen-Dominant SIBOHydrogenBloating, gas, loose stools, or alternating bowel patterns.Often caused by overgrowth of fast-fermenting bacteria. Typically responds well to targeted antimicrobials.
Methane-Dominant Overgrowth (IMO)MethaneChronic constipation, abdominal distention, slow transit.Caused by methane-producing archaea (not technically bacteria). May require combination therapies; more treatment-resistant.
Hydrogen Sulfide SIBOHydrogen sulfideFoul-smelling gas, diarrhea, fatigue, sulfur-egg burps.Difficult to detect without specialized testing. Requires a nuanced treatment approach.

Why SIBO Impacts More Than Digestion

When bacteria proliferate in the small intestine, the effects extend well beyond digestion. Overgrowth damages the intestinal lining, drives nutrient malabsorption (particularly B12, iron, and fat-soluble vitamins), and triggers low-grade systemic inflammation. The result is a body-wide ripple — fatigue, brain fog, skin issues, and mood changes — that rarely connects back to the gut without the right workup.

Dr. Shustina reviewing a care plan with a patient.

Common Signs of SIBO Include

Persistent bloating, especially after meals
Excessive gas or belching
Diarrhea, constipation, or alternating bowel habits
Nutrient deficiencies (B12, iron, fat-soluble vitamins)
Unexplained fatigue or low energy
Headaches or brain fog
Skin issues or rosacea-like flares
Food intolerances that seem to multiply over time
Joint pain or unexplained inflammation

Diagnostic Options at Whole Gut Health

Accurate SIBO diagnosis is the foundation of effective treatment — and the right test depends on your symptom pattern. At Whole Gut Health we use the latest diagnostic tools to identify both the presence and the specific type of overgrowth driving your symptoms.

Testing options may include:

SIBO Breath Testing using glucose or lactulose substrates to measure hydrogen and methane gas production.
TrioSmart™ Breath Testing — advanced 3-gas panel that also measures hydrogen sulfide, the gas behind the most overlooked SIBO subtype.
Applied Kinesiology (muscle testing) to identify root causes and triggers — a broader signal than laboratory tests alone.
Osteopathic Visceral Evaluation to assess motility, structural restrictions, and the small-bowel environment.
Comprehensive Stool Analysis to evaluate the broader microbiome, inflammation markers, and digestive function.
Functional Lab Work including nutrient assessments, inflammatory markers, and digestive enzyme function.

We customize testing protocols based on your unique symptom pattern and medical history to ensure we identify the right subtype and all contributing factors.

A consultation room at the Whole Gut Health office.
Our approach

Why Whole Gut Health is different

At Whole Gut Health, we go beyond conventional symptom management and traditional functional medicine protocols. We trust your body's innate ability to heal itself when given the right support.

In Dr. Shustina's many years of practice, she has seen that many digestive diseases have their root cause in emotional traumas and unhealed wounds. When these underlying causes are healed, the body can heal from the inside out in a lasting way.

We focus on the mind-gut connection, incorporating energy healing techniques, personalized nutrition that evolves as you heal, and integrative approaches addressing mind, body, and spirit. If this resonates with you, contact our office to schedule your consultation and take the first step on your healing journey.

Our SIBO Treatment Approach

Our three-phase SIBO protocol moves from identifying the subtype and its drivers, to clearing the overgrowth, to rebuilding motility and microbiome resilience so the overgrowth doesn’t come back.

Phase 1 — Assessment & Root-Cause Identification

  • In-depth intake and medical history review
  • Breath testing to identify SIBO subtype (hydrogen, methane, hydrogen sulfide)
  • Comprehensive lab work and functional testing
  • Applied kinesiology to surface contributing factors
  • Evaluation of motility, previous infections, and medication effects
  • Assessment of stress and gut-brain dysfunction

Phase 2 — Targeted Intervention

  • Herbal antimicrobials matched to your specific SIBO subtype
  • Selective use of prescription antibiotics when indicated
  • Motility support via visceral manipulation and targeted supplementation
  • Combination therapies for methane-dominant overgrowth
  • Personalized diet with strategic food reintroductions
  • Energy medicine and breathwork to support the gut-brain axis

Phase 3 — Rebuilding & Prevention

  • Strategic reintroduction of gut-healing foods
  • Ongoing motility support to prevent stagnation
  • Long-term microbiome restoration and diversity building
  • Sustainable lifestyle and nervous-system practices
  • Monitoring to catch and address early recurrence

Expert-Led, Personalized Care

Dr. Alexandra Shustina is a board-certified gastroenterologist and internist specializing in complex digestive disorders, gut health, and the gut–brain connection. Drawing from both conventional gastroenterology and integrative medicine, she takes a comprehensive approach to uncovering the underlying factors contributing to illness and guides patients toward lasting wellness.

At Whole Gut Health, every patient receives highly personalized care rooted in a deep understanding of digestive health, nutrition, the gut microbiome, and the interconnected systems that influence overall well-being. By combining evidence-based medicine with a thoughtful, individualized approach, we help patients move beyond symptom management and create a clear path toward long-term healing and vitality.

Dr. Alexandra Shustina at Whole Gut Health.
Frequently Asked Questions

Common questions, answered

What is SIBO?

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SIBO stands for Small Intestinal Bacterial Overgrowth. It occurs when there's an abnormal increase in bacteria in the small intestine, where bacterial levels should normally be much lower than in the large intestine.

What are the different types of SIBO?

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SIBO is categorized based on the type of gas produced during bacterial fermentation:

Hydrogen-Dominant SIBO

  • Gas produced: Hydrogen
  • Common symptoms: Bloating, gas, loose stools, or alternating bowel patterns
  • Often caused by overgrowth of fast-fermenting bacteria

Methane-Dominant Overgrowth (IMO)

  • Gas produced: Methane
  • Common symptoms: Chronic constipation, abdominal distention
  • Caused by methane-producing archaea (not technically bacteria)
  • May be more treatment-resistant

Hydrogen Sulfide SIBO

  • Gas produced: Hydrogen Sulfide
  • Common symptoms: Foul-smelling gas, diarrhea, fatigue
  • Difficult to detect without specialized testing
  • Requires a nuanced treatment approach

What are the common signs and symptoms of SIBO?

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  • Persistent bloating, especially after meals
  • Excessive gas or belching
  • Diarrhea, constipation, or alternating bowel habits
  • Nutrient deficiencies or unexplained fatigue
  • Headaches or brain fog
  • Skin issues

How is SIBO diagnosed?

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Accurate diagnosis is essential for effective treatment. Testing options include:

Breath Testing

  • Uses glucose or lactulose substrates
  • Measures hydrogen and methane gas levels

TrioSmart™ Testing

  • Advanced testing that includes measurement of hydrogen sulfide gas
  • Provides comprehensive gas analysis

Functional Lab Work

  • Assesses related nutrient deficiencies
  • Checks for inflammation markers
  • Evaluates digestive enzyme function

Testing protocols are selected based on your specific symptoms and medical history to ensure accurate and actionable results.

What does SIBO treatment involve?

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Our comprehensive three-phase SIBO protocol includes:

Phase 1: Assessment and Root-Cause Identification

  • In-depth intake and medical history review
  • Comprehensive lab work
  • Functional testing strategies including applied kinesiology
  • Identification of contributing factors such as: Motility issues
  • Medication use
  • Previous infections

Phase 2: Targeted Intervention

  • Herbal antimicrobials based on your SIBO type
  • Rare use of prescription antibiotics
  • Motility support using visceral manipulation and targeted supplementation
  • Methane-producing overgrowths may require combination therapies
  • Targeted and personalized diet

Phase 3: Rebuilding and Prevention

  • Strategic reintroduction of gut-healing foods
  • Motility support
  • Long-term microbiome support to prevent recurrence
  • Sustainable lifestyle changes to maintain and prevent

Why is it important to identify the specific type of SIBO?

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Each SIBO subtype presents with different symptoms and requires a different treatment strategy. For example:

  • Hydrogen-dominant SIBO may respond well to certain antimicrobials
  • Methane-dominant overgrowth often requires combination therapies and is more treatment-resistant
  • Hydrogen sulfide SIBO needs specialized testing and a nuanced treatment approach

Can SIBO recur after treatment?

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Yes, SIBO can recur if underlying causes aren't addressed. This is why our protocol includes a comprehensive rebuilding and prevention phase that focuses on:

  • Supporting proper gut motility
  • Healing the intestinal lining
  • Maintaining long-term microbiome balance
  • Addressing root causes that led to SIBO initially

What makes your approach to SIBO treatment different?

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At Whole Gut Health, we combine evidence-based comprehensive strategies from conventional gastroenterology, osteopathic medicine, and energy healing using a functional and integrative approach. Our care is led by Dr Shustina, a board-certified gastroenterologist, experienced in functional medicine with deep understanding of:

  • The gut microbiome
  • Advanced diagnostics
  • Personalized treatment protocols based on your specific SIBO type and underlying causes

Who provides SIBO care at your practice?

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Dr. Alexandra Shustina is a board-certified gastroenterologist and internist who serves as Miami's premier gut health specialist. She has training in both conventional gastroenterology and functional gut health, with expertise in the gut microbiome and its role in health and wellness.

How do I get started with SIBO testing and treatment?

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The first step is scheduling a comprehensive consultation where we'll:

  • Review your symptoms and medical history
  • Determine the most appropriate testing strategy
  • Develop a personalized treatment plan based on your specific needs

Contact our office to schedule your initial consultation and begin your journey toward optimal gut health.

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Dr. Shustina goes to the root level of the issue, not only superficial, so there's healing.

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She has significantly improved my health. I was suffering from Ulcerative Colitis and now live normally.

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Dr. Shustina has helped me change my lifestyle and heal my gut in a way I thought impossible.

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Dr. Shustina is the best doctor I have ever been to. She assesses the root of the problem.

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Dr. Shustina has a wealth of knowledge and is helping me heal years of gastrointestinal issues.

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Dr. Shustina is a fantastic doctor who truly cares. Her holistic approach attacks the root cause.

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