• All
• False (10)
• Not proven (13)
• Partly true (5)
• True (1)

• False

  “A urine mycotoxin test shows whether I have mould poisoning.”

  Mycotoxins are also found in the urine of healthy people because they come from food. There are no levels above which they make you ill. The US CDC warns against these tests.

  Evidence in the chapter: Mould: mycotoxins in food and damp in the home Copy link

• False

  “A probiotic is a probiotic; what matters is lots of bacteria.”

  The effect depends on the strain. In IBS, individual strains helped in meta-analyses, other strains of the same species did not. Many products only name the species.

  Evidence in the chapter: Spore-forming bacteria: Bacillus and co. as probiotics Copy link

• False

  “A low DAO value in the blood proves histamine intolerance.”

  In studies the blood test does not reliably separate affected people from healthy ones. A food diary, a low-histamine trial phase and ruling out other causes tell you more.

  Evidence in the chapter: Histamine intolerance: much searched, little proven Copy link

• False

  “Candida in the stool means a fungal infection of the gut.”

  In many people Candida is part of the normal gut flora in small numbers. Finding it in stool alone is not a result that needs treatment.

  Evidence in the chapter: Fungi in the gut: what is true about Candida Copy link

• False

  “Spore probiotics settle permanently in the gut.”

  Spores germinate in the gut, become briefly active and then move on. After stopping, they disappear within days.

  Evidence in the chapter: Spore-forming bacteria: Bacillus and co. as probiotics Copy link

• False

  “Fasting detoxes the gut, and symptoms during fasting show that toxins are being eliminated.”

  False. Fasting markedly changes the gut microbiota and metabolism, but there is no evidence of “detoxification”. Headache, dizziness or nausea during fasting usually have simple causes such as lack of fluid and salt, caffeine withdrawal or low blood sugar.

  Evidence in the chapter: Longer fasting: water fasting, therapeutic fasting and fasting-mimicking Copy link

• False

  “Certain plants or fibres work like “natural Ozempic”.”

  False. Fibre stimulates the body's own GLP-1 via gut bacteria, but only briefly and weakly. For berberine, weight loss in studies averaged less than one kilogram; for the drug semaglutide it was around 15 per cent of body weight.

  Evidence in the chapter: GLP-1 from the gut: what bacteria do and what “natural Ozempic” cannot do Copy link

• False

  “A liver and gallbladder flush with olive oil washes out gallstones.”

  False. The greenish “stones” afterwards consist of fatty acids, a kind of soap made from the oil itself. Real gallstones are not flushed out this way, and if stones are present, the cleanse can trigger a colic.

  Evidence in the chapter: Pressure under the right ribs: bile, liver and gallstones Copy link

• False

  “If an all-meat diet ends the bloating, the gut is healed.”

  False. Without carbohydrates and fibre, gut bacteria have less to ferment, so less gas is produced. At the same time, butyrate producers decline. This is symptom control by starving the bacteria, not healing, and long-term data are missing.

  Evidence in the chapter: Carnivore and keto: less gas, but at what cost? Copy link

• False

  “If you have diverticula, you must avoid nuts, seeds and popcorn.”

  False. In a study of more than 47,000 men, those who often ate nuts or popcorn tended to have diverticulitis less often. That seeds get stuck in diverticula and trigger inflammation is not supported by evidence.

  Evidence in the chapter: Diverticula, haemorrhoids and fissures: what can go wrong at the end of the gut Copy link

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