Fibre is often overlooked in canine nutrition, yet it plays a crucial role in digestive health, weight management, and even disease prevention. While dogs are facultative carnivores, meaning they can digest both plant and animal matter, the right type and amount of fibre can significantly improve their overall well-being. This blog will explore the different types of fibre, their sources, optimal dietary levels, and how they impact dogs with specific health conditions.

What is Fibre?

Fibre is a type of carbohydrate found in plant-based foods that resists digestion in the small intestine. It moves into the colon, where it is either fermented by beneficial bacteria or passes through unchanged, impacting digestive function in various ways.

Soluble vs. Insoluble Fibre: What’s the Difference?

Fibre is generally classified into two categories: soluble and insoluble, both of which serve different purposes in a dog's diet.

Soluble Fibre dissolves in water, forming a gel-like substance in the gut. It is fermentable and serves as a prebiotic, feeding beneficial gut bacteria. This type of fibre helps regulate blood sugar, improves gut health, and aids in stool consistency.
Insoluble Fibre does not dissolve in water and passes through the digestive system largely intact. It adds bulk to stools, speeds up transit time in the intestines, and can assist with regular bowel movements.

Food Sources of Soluble and Insoluble Fibre

Understanding which foods provide which type of fibre can help in tailoring a diet to a dog’s needs.

Soluble Fibre Sources:
- Oats
- Apples (without seeds)
- Carrots
- Psyllium husk
- Sweet potatoes
- Flaxseeds
Insoluble Fibre Sources:
- Green beans
- Pumpkin
- Broccoli
- Celery
- Whole grains (such as brown rice and barley)
- Bran

How Much Fibre Do Dogs Need?

Fibre requirements for dogs vary based on age, breed, health conditions, and diet type. Fibre levels in commercial diets typically range from 2% to 5% on a dry matter basis (DMB), but therapeutic diets can contain significantly higher amounts.

Healthy Adult Dogs: 2-5% DMB
Dogs with Diabetes: 7-10% DMB (soluble fibre helps slow glucose absorption)
Dogs with Obesity: 8-17% DMB (increased insoluble fibre promotes satiety and weight loss)
Dogs with Colitis or IBD: 5-10% DMB (moderate fibre supports gut health without excessive fermentation)
Dogs with Chronic Diarrhoea: 7-10% DMB (soluble fibre aids in stool consistency)
Dogs with Constipation or Anal Gland Issues: 8-15% DMB (insoluble fibre promotes stool bulk and anal gland expression)

Why raw diets wont always help anal gland issues

A common myth in raw feeding communities is that raw vegetables help with anal gland problems. However, dogs lack the enzyme cellulase, meaning they cannot break down the cellulose walls of raw vegetables effectively. This means raw vegetables pass through undigested and do not contribute significantly to stool bulk.

To make plant matter digestible for dogs, it must be:

Pureed (breaking down the cell walls)
Lightly cooked or steamed (softens fibre for better digestibility)

Instead of raw vegetables, incorporating insoluble fibre sources like steamed sweet potato, ground flaxseeds, or psyllium husk is far more effective for improving anal gland health.

Benefits of Fibre for Dogs

1. Supports Digestive Health

Fibre can help regulate bowel movements, reducing both diarrhoea and constipation. Soluble fibre promotes a balanced gut microbiome, while insoluble fibre ensures regular stool passage.

2. Aids in Weight Management

High-fibre diets help dogs feel full longer, reducing calorie intake and promoting weight loss. A study published in The Journal of Veterinary Internal Medicine (Laflamme, 1997) found that dogs on a high-fibre diet showed significant weight loss compared to those on low-fibre diets.

3. Regulates Blood Sugar in Diabetic Dogs

Soluble fibre slows glucose absorption, helping stabilise blood sugar levels in diabetic dogs. A study in The American Journal of Veterinary Research (Nelson et al., 2000) demonstrated that high-fibre diets improved glycemic control in diabetic dogs.

4. Improves Anal Gland Health

A common cause of anal gland impaction is soft stools (or too small and too firm stools). Insoluble and soluble fibre helps create a firm, bulky stools that naturally express the anal glands, reducing the risk of blockages and infections.

5. Enhances Gut Microbiota and Immune Function

Prebiotic fibres (such as inulin and FOS) promote the growth of beneficial gut bacteria, which can strengthen the immune system and reduce inflammation.

Which Dogs Benefit from Higher Fibre Diets?

Obese Dogs

Fibre promotes satiety, reducing calorie intake. Dogs prone to obesity, such as Labradors and Beagles, benefit from diets with 8-12% fibre DMB.

Diabetic Dogs

Soluble fibre slows glucose absorption, making it crucial for diabetic dogs, particularly those on insulin therapy.

Dogs with Chronic Diarrhoea or Colitis

Soluble fibre (such as psyllium husk) helps create well-formed stools by absorbing excess water.

Dogs with Anal Gland Issues

Increasing insoluble and soluble fibre in the diet promotes firm (but not too firm) stools that are larger and help naturally express the anal glands.

Senior Dogs

Older dogs can experience slower digestion and constipation. Moderate fibre levels (5-8% DMB) can help maintain regularity.

Final Thoughts

Fibre plays a vital role in canine nutrition, but it must be tailored to each dog’s needs. While both soluble and insoluble fibre offer unique benefits, their sources and digestibility should be carefully considered. Instead of relying on raw vegetables for digestive health, incorporating cooked, pureed, or specific fibre-rich ingredients can provide better results.

If your dog has specific dietary needs, consult a professional canine nutritionist to create a balanced diet that optimally supports their health. Alternatively complete our FREE DIET ASSESSMENT here for your dog

References:

Laflamme, D. (1997). "Effect of diet composition on canine weight loss and maintenance." Journal of Veterinary Internal Medicine.
Nelson, R. W., et al. (2000). "Effects of dietary fibre on glycemic control in dogs with diabetes mellitus." American Journal of Veterinary Research.

The Importance of Fibre in a Dog’s Diet: Soluble vs. Insoluble Fibre & How It Affects Canine Health