Help! I’ve Got Diarrhoea – What’s Going On?

By Lucy Sugars, Nutritional Therapist

If you’re dealing with frequent or unpredictable diarrhoea, you’re not alone. I work with many clients who experience gut issues — and I know how disruptive it can be to everyday life. The good news is, there are many possible causes we can explore and support naturally.

🚨 First Things First

If diarrhoea is new, persistent, or comes with other symptoms like bleeding, weight loss or fever, please speak to your GP first. It’s important to rule out serious causes such as:

Inflammatory bowel disease (IBD)

Coeliac disease

Bacterial or viral infections

Colon cancer

Acute diarrhoea may require medication or hospital treatment to avoid dehydration. Once you’ve ruled out more serious issues, nutrition and lifestyle support can make a huge difference.

💩 What Causes Diarrhoea?
Here are the most common contributors I see in clinic — some obvious, others less so:

1. Infections (Bacterial, Viral, or Parasitic)
Norovirus, Salmonella, E. coli and parasites like Giardia can all cause sudden, intense diarrhoea. In many cases, rest, fluids, and time are enough. But some infections may require antibiotics or anti-parasitic treatment.

2. Coeliac Disease
An autoimmune condition where gluten damages the small intestine, affecting nutrient absorption. Diarrhoea, bloating, and fatigue are common symptoms. It affects 1 in 100 people and is often misdiagnosed as IBS. Proper diagnosis and a lifelong gluten-free diet are essential.

3. Non-Coeliac Gluten Sensitivity
Even if you don’t have Coeliac disease, gluten may still be triggering symptoms. Some people are fine with small amounts; others feel better avoiding it entirely. During a trial elimination, opt for whole foods like rice, quinoa, potatoes and avoid over-processed gluten-free swaps.

4. Lactose Intolerance
Lactose is the sugar in milk. If you lack enough of the enzyme lactase, dairy can lead to bloating, gas and diarrhoea. Try lactose-free options first — if that helps, dairy may be part of the issue.

5. Non-IgE Mediated Food Reactions
These are delayed immune responses to foods that don’t involve classic allergy pathways. Common triggers include:

Wheat

Eggs

Milk

Soy

Citrus fruits

Tomatoes

Shellfish

Nuts

Kiwi, avocado, and coconut
A detailed food and symptom diary — and sometimes an elimination diet — can help identify triggers.

6. FODMAPs
These fermentable carbs are found in foods like onions, garlic, apples, lentils, and wheat. They can pull water into the bowel and cause fermentation, bloating and diarrhoea — especially in people with IBS. A low FODMAP diet, guided by a professional, can help identify your triggers.

7. SIBO (Small Intestinal Bacterial Overgrowth)
When bacteria overgrow in the small intestine, they can cause gas, bloating, diarrhoea, or constipation. A tailored plan of diet, supplements, and possibly testing is often required.

8. High Doses of Magnesium or Vitamin C
Supplements like magnesium citrate or ascorbic acid (vitamin C) can cause diarrhoea at high doses. If you’re experiencing loose stools and taking supplements, it’s worth reviewing the type and dosage with a practitioner.

9. Sugar Alcohols
Found in sugar-free gum, protein bars, and low-carb products, sugar alcohols like xylitol, sorbitol, erythritol and mannitol can trigger diarrhoea — especially in large amounts.

10. Alcohol
Alcohol irritates the gut. Red wine, beer and cider are common triggers, especially in excess. If diarrhoea strikes after drinking, try removing alcohol first before cutting out foods unnecessarily.

11. Gums and Additives in Processed Foods
Additives like xanthan gum, guar gum, carrageenan, and acacia gum are common in processed and gluten-free foods. Some sensitive individuals find these ingredients upset their digestion.

12. Stress
The gut and brain are closely connected. Ongoing stress can trigger or worsen diarrhoea by activating the sympathetic nervous system (your “fight or flight” response). Stress may also:

• Alter gut bacteria
• Slow digestion
• Reduce stomach acid

Mind-body strategies like breathwork, meditation, yoga, or adaptogenic herbs can all support your nervous system and gut health.

✅ Final Thoughts
There’s no one-size-fits-all reason for diarrhoea. The causes are varied — from food sensitivities to gut infections and stress.

If you’re struggling with digestive symptoms and want to get to the root cause, I can help. Together we’ll look at your diet, health history, possible triggers, and create a clear plan to move forward.

👉 Book an appointment or get in touch for personalised support.