BLOATING: WHY IT HAPPENS, WHAT TESTS REVEAL, AND HOW TO ACTUALLY FIX IT

BLOATING: WHY IT HAPPENS, WHAT TESTS REVEAL, AND HOW TO ACTUALLY FIX IT

Bloating — The Full Picture

Bloating: Why It Happens,
What Tests Reveal, and
How to Actually Fix It

Nearly two thirds of UK adults experience bloating regularly — but most dismiss it as normal, tolerate it indefinitely, or try random dietary changes that never quite work. Here's what's actually causing it, what the right tests reveal, and how to finally get to the root of it.

64% of UK adults experience bloating in any given month
1 in 5 Britons have IBS — the most common bloating diagnosis
52% of the UK population may have gut microbiome dysbiosis
42% avoid specific foods due to gut symptoms without ever testing

Bloating Is a Symptom, Not a Diagnosis. And the Cause Matters Enormously.

Bloating is one of the most universal and frustrating health complaints — and one of the most misunderstood. A 2025 University of Glasgow study found that 64% of UK adults experienced bloating in the past month, even among those with no diagnosed gut condition. It's so common that most people accept it as normal. It isn't.

The problem is that bloating has dozens of possible causes — from what you eat and how you eat it, to infections, hormonal imbalances, food intolerances, gut bacteria overgrowth, thyroid dysfunction, and occasionally something more serious that warrants medical investigation. Treating all bloating with the same approach — avoiding beans, taking probiotics, cutting out gluten — is why so many people make limited progress. The cause determines the solution.

And a 2024 UCL study of over 400,000 UK adults found that common blood tests — when properly interpreted — can significantly improve the diagnostic journey for people presenting with bloating, helping identify serious underlying conditions far earlier. Bloating is worth investigating properly. Not tolerating indefinitely.

Bloating is your gut communicating. The question isn't how to silence it — it's how to understand what it's saying.


What's Actually Behind the Bloat — and Why Most People Never Find Out

Most Common
IBS & Gut Motility
Irritable Bowel Syndrome affects 1 in 5 Britons and is the most commonly diagnosed cause of bloating. IBS involves abnormal gut motility — food moving too fast, too slowly, or irregularly — combined with visceral hypersensitivity (the gut feeling sensations more acutely). The microbiome composition in IBS is measurably different from healthy controls — with lower diversity and increased inflammatory bacteria. IBS is a diagnosis of exclusion: other causes must be ruled out first.
Test: microbiome, calprotectin
Very Common & Often Missed
SIBO — Bacterial Overgrowth
Small Intestinal Bacterial Overgrowth occurs when bacteria that belong in the large intestine migrate into the small intestine, where they ferment food — particularly carbohydrates — producing hydrogen and methane gases that cause severe, rapid-onset bloating, often within minutes of eating. SIBO is a common cause of bloating that doesn't respond to standard dietary advice and is frequently misdiagnosed as IBS. Detected through a lactulose or glucose breath test, not a blood test.
Test: SIBO breath test
Frequently Undiagnosed
Coeliac Disease
Coeliac disease is an autoimmune condition where gluten triggers an immune response that damages the gut lining — causing bloating, diarrhoea, fatigue, anaemia, and nutrient malabsorption. Critically, it affects around 1 in 100 people in the UK but around 500,000 people remain undiagnosed. A blood test — anti-tissue transglutaminase (tTG-IgA) antibodies — is the standard first-line screen. Critically, you must be eating gluten at the time of testing for results to be accurate.
Test: tTG-IgA blood test
Overlooked Connection
Thyroid Dysfunction
An underactive thyroid slows everything down — including gut motility. Sluggish bowel movement allows food to ferment longer, producing more gas and causing bloating, constipation, and abdominal discomfort. Many people with hypothyroidism report significant improvement in digestive symptoms when thyroid function is corrected. Thyroid dysfunction affects 1 in 20 adults in the UK and is commonly missed — especially in women, where it is 6x more prevalent. A full thyroid panel is a crucial part of any unexplained bloating investigation.
Test: TSH, Free T3, Free T4
Hormonal Link
Oestrogen & the Gut-Hormone Axis
The gut and hormones are in constant two-way communication. Oestrogen affects gut motility, permeability, and the microbiome composition. Fluctuating oestrogen — in the premenstrual phase, perimenopause, and post-menopause — is a significant and under-recognised driver of bloating and IBS-like symptoms. Conversely, a disrupted gut microbiome (called dysbiosis) impairs oestrogen metabolism — a connection known as the "estrobolome." Testing hormones alongside gut markers gives the most complete picture for women experiencing cyclical or perimenopausal bloating.
Test: oestradiol, FSH, LH
Immune Reaction
Food Intolerances & IgG Reactions
Food intolerances — unlike allergies, which are immediate — produce delayed immune reactions (IgG-mediated) that can occur hours or even days after eating a trigger food. Common culprits include dairy, gluten, eggs, soy, and certain fruits and vegetables. The delay makes them extremely difficult to identify through trial and error alone. An IgG food sensitivity panel tests immune reactivity across 200+ foods simultaneously — providing a roadmap that removes guesswork. Note: IgG testing is privately available and clinically useful, though it remains debated among allergists.
Test: IgG food sensitivity panel
Stomach Bacteria
H. pylori Infection
Helicobacter pylori is a bacterium that colonises the stomach lining and disrupts normal acid production and digestion. It causes upper abdominal bloating, reflux, heartburn, nausea, and a feeling of heaviness after meals — symptoms that are frequently misattributed to stress or food choices. H. pylori affects around 40% of the global population, often acquired in childhood. It's detected via a simple blood antibody test, stool antigen test, or breath test — and is treated effectively with a short course of antibiotics.
Test: H. pylori blood or breath test
Malabsorption
Lactose & Fructose Malabsorption
Lactose intolerance — the inability to digest the sugar in dairy — affects around 65% of the world's population to some degree, with significant variation by ethnicity. Fructose malabsorption is similarly widespread. Both cause bloating, gas, cramping, and diarrhoea when the relevant sugars reach the large intestine undigested and are fermented by bacteria. Hydrogen breath tests can diagnose both conditions directly. A full-fat elimination trial can also be diagnostic — but testing removes ambiguity entirely.
Test: lactose/fructose breath test

When bloating warrants urgent medical attention

Most bloating is functional and benign — but certain patterns require prompt GP investigation. See your doctor urgently if bloating is accompanied by: unexplained weight loss, blood in stools, persistent vomiting, difficulty swallowing, a palpable abdominal lump, or if bloating is new and persistent in someone over 50. A 2024 UCL study found that blood tests — particularly FBC, liver function, and inflammatory markers — significantly improve early cancer detection in people presenting with bloating. Don't ignore persistent bloating that doesn't have an obvious dietary cause.


Why Bloating Is Often a Hormone Problem — Not Just a Food Problem

This is the connection most people — and many healthcare providers — miss entirely. The gut and the endocrine (hormone) system are in constant two-way dialogue. Hormones regulate gut motility, gut barrier integrity, and microbiome composition. And the gut, in turn, metabolises and recycles hormones. When this system is disrupted, the result is often bloating, digestive distress, and unexplained gut symptoms that don't respond to dietary changes alone.

Hormones that directly affect gut function and bloating

Thyroid hormones (T3/T4)
High — regulate gut motility directly
Oestrogen (cyclical changes)
High — affects motility & permeability
Progesterone
High — slows gut motility (luteal phase)
Cortisol (chronic stress)
High — impairs gut barrier integrity
Insulin (blood sugar dysregulation)
Moderate-high — drives dysbiosis
Testosterone (men & women)
Moderate — affects gut microbiome diversity

Testing hormones alongside gut markers — particularly thyroid, oestrogen, and cortisol — is essential for understanding bloating that has a cyclical pattern, worsens with stress, or doesn't respond to dietary interventions alone.

The premenstrual week is a particularly common time for bloating — driven by the progesterone surge that slows gut motility, combined with oestrogen fluctuations that alter water retention and gut sensitivity. Perimenopause brings similar disruption, as declining oestrogen dysregulates the microbiome and increases gut permeability. Testing hormones at these life stages, alongside gut markers, often reveals patterns that dietary changes alone could never address.


What to Test — and What Each One Reveals

Bloating investigation is not one-size-fits-all. The right tests depend on your symptoms, their timing, their triggers, and your health history. Here's a comprehensive overview of the testing landscape — from standard blood tests to specialist gut panels.

Blood tests — the essential starting point

Blood Test

Full Blood Count + CRP

A full blood count looks for anaemia (common in coeliac and IBD), elevated white cell count (infection or inflammation), and platelet abnormalities. High-sensitivity CRP or ESR flags systemic inflammation — helping distinguish functional bloating (IBS) from inflammatory bowel disease. The 2024 UCL study found these markers significantly improved early cancer detection in people with bloating.

Detects: Anaemia, infection, inflammation, IBD vs IBS

Blood Test

Coeliac Screen (tTG-IgA)

Anti-tissue transglutaminase IgA antibodies are the standard first-line test for coeliac disease. Total IgA should always be measured alongside it — IgA deficiency (present in ~2% of the population) produces a false-negative result. Must be performed while eating gluten — a gluten-free diet before testing will give a normal result even in coeliac disease.

Detects: Coeliac disease — affects ~1% of UK population, 500,000 undiagnosed

Blood Test

Thyroid Panel (TSH, Free T3, Free T4, Anti-TPO)

A full thyroid panel is essential for anyone with unexplained bloating and constipation — particularly women. Subclinical hypothyroidism (TSH elevated within "normal" range) significantly slows gut motility. Anti-TPO catches Hashimoto's, which can be present even with a normal TSH and contributes to gut symptoms through immune activation.

Detects: Hypothyroidism, Hashimoto's — both cause bloating via slow gut transit

Blood Test

Hormone Panel

For women with cyclical bloating, perimenopausal symptoms, or bloating that worsens premenstrually — oestradiol, progesterone, FSH, and LH give context. For all genders, cortisol and DHEA-S reveal whether chronic stress is driving gut barrier dysfunction and dysbiosis. Blood sugar (HbA1c) reveals whether insulin dysregulation is contributing to microbiome imbalance.

Detects: Hormonal bloating drivers — cyclical, perimenopausal, stress-related

Stool & breath tests — when blood tests don't give the full picture

Stool Test

Comprehensive Gut Microbiome Panel

A comprehensive stool analysis maps the types and relative abundance of bacteria, fungi, and other microorganisms in the gut. It can identify dysbiosis (imbalanced microbiome), overgrowth of specific harmful bacteria like Klebsiella or Proteobacteria, Candida yeast overgrowth, parasites, and markers of gut inflammation (calprotectin) and digestion (pancreatic elastase). This is the most comprehensive gut health investigation available outside of colonoscopy.

Detects: Dysbiosis, Candida, parasites, gut inflammation, digestive enzyme deficiency

Breath Test

SIBO Breath Test (Lactulose or Glucose)

Measures hydrogen and methane gases exhaled after drinking a sugar solution — gases produced only by bacteria fermenting carbohydrates in the small intestine. A positive result confirms SIBO — bacterial overgrowth in the small intestine — which causes severe, rapid-onset bloating after eating. Particularly useful when bloating occurs within 30–90 minutes of eating, or when symptoms haven't improved with dietary changes.

Detects: Hydrogen SIBO, methane SIBO (now reclassified as IMO — intestinal methanogen overgrowth)

Breath Test

H. pylori Urea Breath Test

The gold standard for detecting active H. pylori infection. More accurate than blood antibody testing (which can remain positive even after successful treatment). The patient drinks a urea solution labelled with a carbon isotope — H. pylori breaks it down, releasing labelled CO2 that is detected in exhaled breath. Simple, non-invasive, and widely available privately.

Detects: Active H. pylori infection — upper bloating, reflux, heartburn

Blood Test

IgG Food Sensitivity Panel (200+ foods)

Measures IgG antibody reactions to a broad panel of foods — identifying delayed immune responses that can occur hours or days after eating a trigger. Particularly useful when symptoms are inconsistent, delayed, or difficult to link to specific meals despite careful food diaries. Provides a targeted starting point for an elimination and reintroduction protocol rather than blanket food avoidance.

Detects: Delayed food immune reactions — bloating, fatigue, brain fog, skin issues


A Practical, Test-Led Approach to Getting Your Gut Right

The most effective approach to chronic bloating is to test first, then treat. Removing foods you don't actually react to, taking supplements you don't need, or following protocols designed for a cause you don't have is both frustrating and unnecessary. Here's a structured approach.

1

Start with a blood panel — rule out the serious stuff first

Full blood count, CRP, coeliac screen (tTG-IgA + total IgA), thyroid panel (TSH, Free T3, Free T4, Anti-TPO), liver function, and vitamin panel (B12, folate, iron/ferritin, vitamin D). This rules out coeliac disease, thyroid dysfunction, inflammatory bowel disease, anaemia, and nutrient malabsorption — all of which cause bloating and are frequently missed.

2

For women — add a hormone panel

If bloating is cyclical, worsens premenstrually, or has changed around perimenopause — test oestradiol, progesterone, FSH, LH, and cortisol. The gut-hormone axis is real and frequently the missing piece for women who've had every gut test come back normal.

3

Consider a SIBO breath test if bloating is rapid and severe after eating

If you bloat within 30–90 minutes of eating — particularly after carbohydrates, fruit, or fermented foods — SIBO is a strong possibility. A lactulose breath test is the standard investigation. If confirmed, a specific SIBO protocol (often including antibiotics or herbal antimicrobials, followed by a rebalancing diet) is very different from standard IBS management.

4

Get a comprehensive microbiome test if dysbiosis is suspected

If blood tests are normal, SIBO has been ruled out, and bloating persists — a comprehensive stool analysis gives the broadest view of what's happening in your gut ecosystem. Identifying specific bacterial imbalances, Candida overgrowth, parasites, or low pancreatic enzyme output allows for genuinely targeted supplementation and dietary intervention.

5

Try an IgG food panel if triggers are delayed and hard to identify

If food diaries and elimination trials haven't given you clear answers — particularly when symptoms appear hours or a day after eating — an IgG food sensitivity panel can identify which foods your immune system is reacting to. Use the results to guide a structured elimination and reintroduction, not as a permanent ban list.

6

Support gut health while you investigate

Regardless of cause, these interventions have broad evidence for gut health and bloating reduction: adequate hydration with electrolytes (Oshun is ideal — it hydrates at a cellular level without artificial additives), a diverse whole-food diet rich in fibre, stress management (cortisol directly increases gut permeability), and avoiding NSAIDs and alcohol during investigations as both damage the gut lining.

You don't have to just live with bloating. You have to find out what's causing it. That starts with testing — not guessing.

Stop Guessing. Start Testing.

Chronic bloating has a cause — and most causes are findable with the right tests. At Boost & Glow, we can help you navigate blood testing, gut health panels, and targeted support to finally get answers.

Explore Boost & Glow → Support Gut Hydration With Oshun →

This blog is for informational purposes only and does not constitute medical advice. Persistent bloating — particularly if accompanied by unexplained weight loss, blood in stools, or new symptoms in people over 50 — should always be assessed by a GP. Always seek personalised medical advice before undertaking testing or making significant changes to your diet or supplement routine.

Related services

Private Blood Tests Book a Consultation IV Therapy & Treatments

0 comments

Leave a comment

Share this post: f 𝕏 in P